KR20140017341A - Apparatus and method for transmitting control information in wireless communication system - Google Patents

Abstract

The present disclosure discloses an apparatus and method for transmitting control information in a wireless communication system. In this specification, the UE triggers transmission of IDC assistance information based on an IDC triggering condition, transmits IDC assistance information including TDM-based DRX operation related information to a source base station, and the source base station based on the IDC assistance information. DRX receiving and receiving an RRC connection reset message including the selected IDC solution, performing measurement and reporting the measurement result without the influence of IDC interference to the source base station, and DRX recommended by the source base station based on the measurement result And receiving a handover command including a configuration from the source base station, wherein the DRX configuration is a DRX configuration configured by applying a wrap-around DRX start offset value transmitted in the handover request. According to the present specification, the DRX operation may be performed when the DRX period is a non-argument of the total system frame number regarding the coexistence interference in the device, and the updated DRX offset value may be transmitted during the handover process.

Description

Apparatus and method for transmitting control information in a wireless communication system {APPARATUS AND METHOD FOR TRANSMITTING CONTROL INFORMATION IN WIRELESS COMMUNICATION SYSTEM}

The present invention relates to a wireless communication system, and more particularly, to an apparatus and method for transmitting control information in a wireless communication system.

Wireless communication systems generally use one bandwidth for data transmission. For example, a second-generation wireless communication system uses a bandwidth of 200 KHz to 1.25 MHz, and a third-generation wireless communication system uses a bandwidth of 5 MHz to 10 MHz. To support increasing transmission capacity, the recent 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) or IEEE 802.16m continues to expand its bandwidth to 20 MHz or more. Increasing the bandwidth to increase the transmission capacity is essential, but supporting large bandwidths even at low levels of required services can result in large power consumption.

Accordingly, a multiple component carrier system has emerged, which defines a carrier having one bandwidth and a center frequency and enables transmission and / or reception of data over a wide band through a plurality of carriers. By using one or more carriers, it is possible to support narrowband and broadband at the same time. For example, if one carrier corresponds to a bandwidth of 5 MHz, it can support a maximum bandwidth of 20 MHz by using four carriers.

Today's ubiquitous access network allows users to connect to different networks in different regions and maintain connectivity anywhere. Conventionally, when one terminal communicates with one network system, a user carries different devices supporting each network system. However, in recent years, as the functions of a single terminal have been advanced and complicated, communication with multiple network systems can be performed simultaneously with only a single terminal, and user convenience has been increased.

However, in the case where one terminal communicates simultaneously on multiple network system bands, in-device coexistence interference may occur. In-device coexistence interference refers to interference when transmission in one frequency band interferes with reception in another frequency band in the same terminal. For example, in-device coexistence interference may be performed between a Bluetooth system band and an 802.16 system band when one terminal simultaneously supports a Bluetooth system and an 802.16 system. In-device co-existence interference can occur mainly when the spacing between frequency band boundaries of heterogeneous network systems is not wide enough.

In DRX, which is a TDM operation among IDC-controlled operations, the DRX cycle may require a period other than an argument of 10240 ms, which is a length of 10 subframes (eg, 60 ms). In this case, since the DRX cycle is not a factor of 10240 ms, a problem occurs that the DRX offset changes in a situation in which the system subframe recurs. Another new type of DRX cycle driving algorithm is needed for this problem.

An object of the present invention is to provide an apparatus and method for transmitting control information in consideration of occurrence of coexistence interference in a device.

Another object of the present invention is to provide an apparatus and method for performing handover by transmitting control information about coexistence interference in a device.

Another technical problem of the present invention is to provide an apparatus and method for performing a DRX operation by transmitting control information about coexistence interference in a device.

Another technical problem of the present invention is to provide an apparatus and method for updating a set DRX offset for preventing in-device coexistence interference.

Another technical problem of the present invention is to provide an apparatus and method for calculating a DRX offset according to a wrap-around number starting from a set DRX offset in consideration of a multiple relationship between a DRX cycle and a system subframe.

Another technical problem of the present invention is to provide an apparatus and method for controlling the transmission of UE assistance information by checking the adequacy of a DRX offset.

Another technical problem of the present invention is to provide an apparatus and method for providing a DRX operation of a terminal using an H / O procedure in an IDC environment.

Another technical problem of the present invention is to provide an apparatus and method for updating a DRX offset between a source base station and a target base station to support a DRX operation of a terminal.

Another technical problem of the present invention is to provide an apparatus and method for transmitting and receiving information for updating a DRX offset between a source base station and a target base station to support a DRX operation of a terminal.

According to an aspect of the present invention, a terminal for transmitting control information in a wireless communication system includes a triggering unit for triggering transmission of IDC assistance information based on an IDC triggering condition; A transmitter for transmitting IDC assistance information including information related to TDM-based DRX operation to a source base station; A receiver configured to receive an RRC connection reconfiguration message including an IDC solution selected by the source base station based on the IDC assistance information; And a measurement unit configured to perform measurement and report a measurement result from which the influence of IDC interference has been removed, to the source base station, wherein the reception unit receives a handover command including a DRX setting recommended by the source base station based on the measurement result. The DRX setting received from a source base station is a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted in a handover request.

According to another aspect of the present invention, a method for transmitting control information by a terminal in a wireless communication system includes: triggering transmission of IDC assistance information based on an IDC triggering condition; Transmitting IDC assistance information including TDM-based DRX operation related information to a source base station; Receiving, by a source base station, an RRC connection reconfiguration message including an IDC solution selected based on the IDC assistance information; Performing the measurement and reporting the measurement result to which the influence of IDC interference has been removed to the source base station; And receiving a handover command from the source base station including a DRX setting recommended by the source base station based on the measurement result, wherein the DRX setting is a wrap-around DRX start offset transmitted at the handover request. Characterized in that it is a DRX configuration configured by applying a value (wrap_arounded_drxStartOffset).

According to another aspect of the present invention, a base station for transmitting control information in a wireless communication system includes a receiving unit for receiving IDC support information or measurement results from the terminal; An IDC solver that selects the most appropriate IDC solution based on the IDC assistance information; A transmitter for including the IDC solution in an RRC connection reconfiguration message and transmitting it to the terminal; And a handover decision unit which performs a handover decision to a target base station based on the measurement result; The transmitter transmits a handover request to the target base station through an X2 interface, and the handover request includes a wrap-around DRX start offset value determined based on a DRX start offset value of a system frame before wrap-around. do.

According to another aspect of the present invention, a method for transmitting control information in a base station in a wireless communication system includes receiving IDC assistance information or a measurement result from a terminal; Selecting the most appropriate IDC solution based on the IDC assistance information;

Including the IDC solution in an RRC connection reconfiguration message and transmitting it to the terminal; Performing a handover decision to a target base station based on the measurement result; And transmitting a handover request to the target base station through an X2 interface, wherein the handover request is a wrap-around DRX start offset value determined based on a DRX start offset value of a system frame before wrap-around Characterized in that it comprises a.

According to the present invention, the DRX operation may be performed when the DRX cycle is a non-argument of the total system frame number regarding the coexistence interference in the device, and the updated DRX offset value may be transmitted during the handover process.

1 illustrates a wireless communication system to which an embodiment of the present invention is applied.
2 is an explanatory diagram for explaining in-device coexistence interference applied to the present invention.
3 shows an example of in-device coexistence interference from an ISM transmitter to an LTE receiver according to the present invention.
4 shows an example in which an ISM band and an LTE band are divided on a frequency band.
5 is an explanatory diagram illustrating an example of mitigating in-device coexistence interference using an FDM scheme according to the present invention.
6 is an explanatory diagram showing another example of mitigating in-device coexistence interference using an FDM scheme according to the present invention.
7 and 8 are explanatory diagrams showing an example of mitigating in-device coexistence interference using a power control scheme according to the present invention.
9 is an explanatory diagram showing an example of mitigating in-device coexistence interference by using a TDM scheme applied to the present invention.
10 shows transmission / reception timings on the time axis of the LTE band and the ISM band which controlled in-device coexistence interference according to the TDM scheme.
11 illustrates another example of mitigating in-device coexistence interference by using a TDM scheme according to the present invention.
12 is a diagram illustrating another example of mitigating in-device coexistence interference using a TDM scheme applied to the present invention.
FIG. 13 is a diagram illustrating another example of mitigating in-device coexistence interference by using a TDM scheme applied to the present invention.
14 and 15 show an example of a DRX operation applied to the present invention.
FIG. 16 is a diagram illustrating a case where a terminal receives an interference signal in a device according to the present invention.
17 is a diagram illustrating an example of a DRX operation to which the present invention is applied.
18 is a flowchart illustrating an example of a DRX operation according to the present invention.
19 is a diagram illustrating an example of a method of obtaining a measured value with the IDC influence removed according to the present invention.
20 is a flowchart illustrating another example of a DRX operation according to the present invention.
21 is a flowchart illustrating still another example of a DRX operation according to the present invention.
22 is a flowchart illustrating an example of an operation of a terminal performing a DRX operation according to the present invention.
23 is a flowchart illustrating an example of an operation of a base station performing a DRX operation according to the present invention.
24 is an example of a block diagram illustrating a terminal and a base station performing a DRX operation according to the present invention.

Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. It should be noted that, in adding reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible even if they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.

In describing the components of the present specification, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. If a component is described as being "connected", "coupled" or "connected" to another component, that component may be directly connected or connected to that other component, but there is another component between each component. It will be understood that may be "connected", "coupled" or "connected".

1 illustrates a wireless communication system to which an embodiment of the present invention is applied.

Referring to FIG. 1, a wireless communication system is widely deployed to provide various communication services such as voice and packet data, and includes a user equipment (UE), a base station 20 (evolved NodeB, eNB), and a WLAN access point. (Wireless LAN Access Point: AP, 30), GPS (Global Positioning System, 40) satellite. Herein, the wireless LAN access point (or wireless LAN) is a device supporting IEEE (Institute of Electrical and Electronics Engineers) 802.11 technology, and IEEE 802.11 can be mixed with a WiFi system.

The terminal 10 may be located within the coverage of multiple networks such as cellular networks, wireless LANs, broadcast networks, satellite systems, and the like. The terminal 10 has a plurality of wireless transceivers for accessing various networks and various services regardless of time and place. For example, a smart phone has a Long Term Evolution (LTE), WiFi, Bluetooth (BT) transceiver and a GPS receiver. As such, the design of the terminal 10 is becoming more complex in order to integrate more and more transceivers into one and the same terminal 10 while maintaining good performance. As a result, in-device coexistence interference (IDC interference) is more likely to occur.

Hereinafter, downlink (DL) means communication from the base station 20 to the terminal 10, and uplink (UL) means communication from the terminal 10 to the base station 20. In downlink, the transmitter may be part of the base station 20 and the receiver may be part of the terminal 10. In addition, in uplink, the transmitter may be part of the terminal 10 and the receiver may be part of the base station 20.

The terminal 10 may be fixed or mobile and may be referred to by other terms such as a Mobile Station (MS), a User Terminal (UT), a Subscriber Station (SS), a Mobile Terminal (MT) . The base station 20 is a fixed station that communicates with the terminal 10 and includes a base station (BS), a base transceiver system (BTS), an access point, a femto base station (Femto BS) (relay).

There are no restrictions on multiple access schemes applied to wireless communication systems. (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier-FDMA , OFDM-CDMA, and the like.

2 is an explanatory diagram for explaining in-device coexistence interference applied to the present invention.

Referring to FIG. 2, the terminal 10 includes an LTE RF 11, a GPS RF 12, and a Bluetooth / WiFi RF 13. Transmit and receive antennas 14, 15, and 16 are connected to each radio frequency (RF). That is, several kinds of RFs are closely mounted in one device platform. Here, the transmit power of one RF may be much greater than the receive power level to another RF receiver. If the frequency spacing between RFs is not sufficient and the filtering technique is not supported, then a transmission signal of one RF may cause significant interference to a receiver of another RF in the device. For example, "A" of FIG. 2 is an example of a path in which the transmission signal of the LTE RF 11 causes in-device coexistence interference with respect to the GPS RF 12 and the Bluetooth / WiFi RF 23, and the "B". Is an example of a path in which a transmission signal of the Bluetooth / WiFi RF 23 causes in-device coexistence interference with respect to the LTE RF 21.

3 illustrates an example of in-device coexistence interference from an ISM (Industrial, Scientific and Medical) transmitter to an LTE receiver according to the present invention. ISM transmitter refers to a transmitter that transmits in the ISB band, a band that can be freely used without a license in the industrial sciences and medical field.

Referring to FIG. 3, it can be seen that the band of the signal received at the LTE receiver overlaps the band of the transmission signal of the ISM transmitter. In this case, in-device coexistence interference may occur. In particular, when receiving a signal through the LTE receiver in the frequency bands F1 to F3, F2 and F3 indicates that the unacceptable interference occurs in the LTE receiver due to the ISM transmitter. Here, F1 to F3 may be frequency bands belonging to one band. However, F1 exists in a band outside the region affected by In-Device Coexistence (IDC), and F2 and F3 belong to the region affected by IDC. That is, within one band, the degree of coexistence interference problem may vary between frequency bands according to the characteristics of a band filter.

4 shows an example in which an ISM band and an LTE band are divided on a frequency band.

Referring to FIG. 4, band 40, band 7, and band 38 are LTE bands. Band 40 occupies 2300-2400 MHz band in TDD (Time Division Duplexing) mode, uplink occupies 2500-2570 MHz band, and downlink occupies 2620-2690 MHz in FDD mode. Band 38 occupies 2570-2620 MHz band in TDD mode. Meanwhile, the ISM band is used as a Wi-Fi channel and a Bluetooth channel and occupies 2400 to 2483.5 MHz. Here, the situation in which coexistence interference occurs in the device is shown in Table 1 below.

Interference band Form of interference Band 40 ISM Tx-> LTE TDD DL Rx Band 40 LTE TDD UL Tx-> ISM Rx Band 7 LTE FDD UL Tx-> ISM Rx Band 7/13/14 LTE FDD UL Tx-> GPS Rx

Referring to Table 1, the notation 'a-b' in the form of interference indicates a situation in which transmitter a causes coexistence interference in a device to receiver b. In band 40, the ISM transmitter causes in-device co-existence interference to the downlink TDD receiver (LTE DL TDD Rx) of the LTE band. A filtering scheme can mitigate some of the coexistence interference in the device, but it is not enough. In addition to the filtering scheme, the application of frequency division multiplex (FDM) scheme can more effectively mitigate in-device coexistence interference.

5 is an explanatory diagram illustrating an example of mitigating in-device coexistence interference using an FDM scheme according to the present invention.

Referring to FIG. 5, the LTE band may be moved in the arrow direction (to the left in the frequency band axis) so that the LTE band does not overlap with the ISM band. This results in handover of the terminal from the ISM band. However, this requires a method in which legacy measurement or new signaling accurately triggers a mobility procedure or radio link failure (RLF) procedure. Alternatively, there may be a method of avoiding a problem in the LTE band with the ISM through filtering or resource allocation. Alternatively, when LTE carrier aggregation is used, overlapping interference may be avoided through a procedure of reconfiguring a set of carriers to be used.

6 is an explanatory diagram showing another example of mitigating in-device coexistence interference using an FDM scheme according to the present invention.

Referring to FIG. 6, the ISM band may be reduced and moved in the direction of the arrow (to the right in the frequency axis) to be separated from the LTE band. In this way, backward compatibility problems may occur. In the case of Bluetooth, the backward compatibility problem may be solved to some extent due to the adaptive frequency hopping mechanism. However, in the case of Wi-Fi, the backward compatibility problem is solved. This can be difficult.

7 and 8 are explanatory diagrams showing an example of mitigating in-device coexistence interference using a power control (PC) scheme according to the present invention.

Referring to FIG. 7, the terminal may lower the transmission power of the LTE signal to a certain level to avoid in-device coexistence interference to improve reception quality of the ISM band. Referring to FIG. 8, the terminal may uniformly transmit the transmission power of the ISM band. By lowering the level, the reception quality of the LTE signal can be improved by avoiding in-device coexistence interference.

9 is an explanatory diagram illustrating an example of mitigating in-device coexistence interference by using a time division multiplexing (TDM) method applied to the present invention.

Referring to FIG. 9, if the reception time of the LTE signal is changed so as not to overlap with the transmission time in the ISM band, in-device coexistence interference may be avoided. For example, if a signal of the ISM band is transmitted at t ₀ , the LTE signal is received at t ₁ .

10 shows transmission / reception timings on the time axis of the LTE band and the ISM band which controlled in-device coexistence interference according to the TDM scheme.

Referring to FIG. 10, it can be seen that in-device coexistence interference can be avoided by the TDM scheme as shown in FIG. 9 without moving between the LTE band and the ISM band.

11 illustrates another example of mitigating in-device coexistence interference by using a TDM scheme according to the present invention.

Referring to FIG. 11, as a TDM scheme based on discontinuous reception (DRX), a pattern periodicity section is a scheduled period section and an unscheduled period section. Splitting can avoid in-device coexistence interference. The UE prevents LTE from transmitting within the unscheduled period to avoid mutual interference between the LTE and the ISM, but the main LTE transmission such as random access or hybrid automatic repeat request (HARQ) retransmission is scheduled. Even within a defined period of time may be allowed. The UE prevents the transmission of the ISM within the scheduled period and allows the transmission of the LTE to avoid mutual interference between the LTE and the ISM. As with the unscheduled period, the main transmission of the ISM band such as Beacon or Wi-Fi may be allowed within the scheduled period. LTE transmission may be prevented to protect the main transmission of the ISM band. In addition, special signaling may be added to protect the main transmission of the ISM band such as a beacon. For example, information on a period of the beacon signaling and a subframe offset may be added. In this case, the subframe offset number and the system frame number may be determined based on "0". The system frame refers to 10 subframes, and the system frame number is one of "0" to "1023" in units of radio frames in the LTE system. Since one radio frame consists of 10 subframes, the UE can know the exact frame position in the system through the subframe offset number and the system frame number.

12 is a diagram illustrating another example of mitigating in-device coexistence interference using a TDM scheme applied to the present invention.

Referring to FIG. 12, as an autonomously denial method to which the TDM scheme is applied, LTE transmission is arbitrarily rejected to protect ISM reception when in-device coexistence interference occurs. In FIG. 12, a checkmarked part means that transmission or reception is approved, and an X-marked part (X) means that transmission or reception is denied. Even if the LTE UL transmission is granted from the base station, the terminal may not perform the LTE UL transmission by denying the grant to protect the ISM reception. Similarly, ISM transmission can be rejected to protect LTE reception. By reducing the ISM transmission power level, reception quality in LTE can be improved.

FIG. 13 is a diagram illustrating another example of mitigating in-device coexistence interference by using a TDM scheme applied to the present invention.

Referring to FIG. 13, as a partial autonomously denial scheme using a TDM scheme, when downlinking ISM transmission in preparation for difficulty in LTE reception of a terminal due to occurrence of IDC interference, a physical downlink (PDCCH) It is a method of partially rejecting ISM transmission of a subframe based on a control channel).

When the UE receives the PDCCH region of LTE, in principle, the UE rejects ISM transmission. However, if there is no downlink resource allocation in the subframe region indicated by the PDCCH based on the PDCCH region, there is no need to deny ISM transmission for the subframe region and the ISM transmission is allowed. Here, the PDCCH region means a region in which a resource region including control information such as resource allocation or grant information and a region necessary for decoding the control information are added together. In case of LTE, it means the sum of the number of OFDM symbols used for PDCCH transmission transmitted by a Physical Control Format Indicator Channel (PCFICH) and the size of a region required for decoding the PDCCH in the UE. In this case, the size of the region required for decoding the PDCCH may vary depending on the implementation of the UE, but may not be larger than one subframe.

Referring to FIG. 13, ISM transmission may be rejected in each of the PDCCH regions 1300, 1310, 1320, 1330, 1340, 1350, 1360, and 1370. In addition, the UE is a non-PDCCH region (non-PDCCH, 1305, 1315, 1325, 1335, 1345, 1355) which is a subframe indicated by the PDCCH regions 1300, 1310, 1320, 1330, 1340, 1350, 1360, and 1370, respectively. It is determined whether downlink resource allocation exists at 1365 and 1375. Downlink resource allocation exists in the non-PDCCH regions 1315, 1335, 1345, and 1355, but no downlink resource allocation exists in the non-PDCCH regions 1305, 1325, 1365, and 1375. Thus, only some non-PDCCH regions 1315, 1335, 1345, and 1355 partially reject ISM transmissions. ISM transmission is allowed for the other non-PDCCH regions 1305, 1325, 1365, and 1375.

14 and 15 show an example of a DRX operation applied to the present invention.

Referring to FIG. 14, a DRX cycle (DRX cycle) 1400 refers to a cycle in which a DRX operation is performed. As an example, there is a long DRX cycle applied in a range between 10 subframes and 2560 subframes. Another example is a short DRX cycle applied in a range of 2 subframes to 640 subframes. At this time, the DRX cycle is applied only while the DRX short cycle timer (drxShortCycleTimer) is operated, and the same long DRX cycle is applied to the range outside the DRX short cycle timer. Here, in the DRX short cycle timer, one short DRX cycle becomes a basic unit. That is, if the length of the short DRX cycle is 10, the time becomes "10 * drxShortCycleTimer". At this time, the length of the short DRX cycle is 1 to 16.

Active time (1405) means the total time that the terminal wakes up and receives the PDCCH. Activity time means the time that the on-duration timer (1415) of the terminal is running, or DRX inactivity timer (drx-InactivityTimer, 1420), DRX retransmission timer (drx-RetransmissionTimer, 1425) or MAC contention It may be a time further including a time that a timer such as a resolution timer (mac-ContentionResolutionTimer) 1430 is running. The start time of the duration timer 1415 is also referred to as the DRX start offset.

The non-active time 1410 refers to a time other than the active time 1405 of the DRX cycle 1400. The terminal does not receive the PDCCH.

The timer unit of the DRX timer, such as the duration timer 1415, the DRX inactivity timer 1420, or the DRX retransmission timer 1425, is a PDCCH-subframe (psf). That is, DRX timers are signaled or operated on a PDCCH-subframe basis. Here, the PDCCH-subframe means a subframe including the PDCCH. For example, in a TDD configuration, DL subframes and Downlink Pilot Time Slot (DwPTS) subframes correspond to PDCCH-subframes. A subframe configured but not suspended for a relay node (RN) corresponds to a PDCCH-subframe.

The start time of the duration timer 1415, that is, the DRX start offset drxStartOffset may be determined to satisfy the following equations (1) and (2). The DRX start offset value may be determined to satisfy the following Equation 1 when the long DRX period is used and to satisfy the following Equation 2 when the short DRX period is used.

Where SFN is a system frame number, subframe number is a subframe number (a value between 0 and 9) in a radio frame, longDRX-Cycle is a long DRX cycle, shortDRX-Cycle is a short DRX cycle and modulo is the remainder of the operation.

Since the DRX start offset value is determined based on a long DRX cycle, when a short DRX cycle is used, the result of performing the remaining operation (modulo operation) can be used as an offset for the DRX operation point.

Referring to FIG. 15, while the duration interval 1515 of the DRX cycle 1500 is operating, the DRX command MAC CE becomes an active time 1505 unless a DRX command MAC control element 1550 is received. Receiving command MAC CE 1550, duration timer 1515 stops, resulting in non-activity time 1510. The length of the duration period 1515 may be psf1 to psf200, that is, one PDCCH-subframe to 200 PDCCH-subframes.

The DRX inactivity timer starts when it receives a PDCCH indicating a new transmission and stops when it receives a DRX command MAC CE.

The DRX retransmission timer starts if data decoding in a corresponding HARQ procedure is not successfully performed within a HARQ round trip time (RTT). When the PDCCH containing the grant message is received for the process, the DRX retransmission timer stops.

FIG. 16 is a diagram illustrating a case where a terminal receives an interference signal in a device according to the present invention. It is classified into seven cases based on the frequency of interference and the strength or power.

Referring to FIG. 16, when the seven cases are classified into four patterns based on the frequency of the interference, case 1 and case 2 are continuous, case 3 and case 4 are frequent, case 5 and Case 6 are sparse, and Case 7 is a pattern of none.

When the seven cases are classified into three patterns based on the intensity of the interference, Case 1, Case 3, and Case 5 are very strong, Case 2, Case 4, and Case 6 are sufficiently weak, Case 7 is a pattern of none.

For example, the case where the terminal determines that the IDC is in progress (on-going IDC, hereinafter called IDC in progress) may be Case 1 and Case 3. The cases are at least a case where the interference is continuous or frequent and is very strong.

On the other hand, a condition that does not correspond to the IDC process but the in-device co-existence interference occurs and the possibility that the in-device co-existence interference is changed to the ongoing state is defined as "the presence of potential in-device co-existence interference" (hereinafter referred to as potential IDC) Is called).

For example, the terminal may determine that case 2, case 4, case 5, and case 6 of FIG. 16 are potential IDC generation. As another example, the terminal may determine that only case 5 having a strong strength is capable of generating potential IDC. Handover, RRC setting / resetting, etc. are not impossible in the potential IDC possible frequency band, and the UE may perform measurement.

As another example, the case where it is determined that the IDC is in progress may be cases 1, 2, 3 and case 4. The cases are cases where interference is continuous or frequent. This is the case where the strength of the interference is not taken into account.

Meanwhile, according to the definition of the above embodiment, cases 5 and 6 may be defined as "in the presence of potential in-device coexistence interference".

As another example, whether IDC is in progress may include interference between IDC and cells (for example, interference of co-channel serving and non-serving cells of the same channel and adjacent channel interference). ), Etc.) and thermal noise can be considered. In other words, IDC, inter-cell interference, adjacent channel interference, and thermal noise may be defined as the IDC in progress for a strong and frequent case. For example, in the case of considering only IDC in FIG. 16, even in case 2 or case 4, IDC may be in progress when cell-to-cell interference, adjacent channel interference, thermal noise, etc. are considerably large.

Now, in accordance with the present invention, a method and apparatus for transmitting control information for controlling in-device coexistence interference will be described. Hereinafter, an operation of reducing, avoiding, or removing interference is collectively referred to as interference control, interference coordination, or interference solution.

However, the DRX operation according to the present invention is not necessarily used to control in-device coexistence interference, but may be applied to an operation other than controlling the in-device coexistence interference.

The present invention can be applied when the DRX period is not a factor of the total system subframe number 10240. This is because the UE may need a period (for example, 60 ms) that is not an argument of the total system subframe number 10240. In this case, we will call the period non-argument.

For example, if the offset of the DRX start time of the IDC control operation generated due to the Bluetooth voice transmission is not fixed, the terminal is affected by IDC interference. For example, in the TDD configuration 6, when the LTE and Bluetooth operate in the slave mode (when the scheduling grant is performed without performing scheduling by itself, the DRX pattern is fixed). When an IDC problem occurs during voice traffic operation, a DRX cycle of 60 ms may be required. 60 ms is a non-argument period because it is not a factor of the total system subframe number 10240.

As another example, when WiFi transmits and receives a beacon (sink channel), in order to protect the transmission of the beacon, the LTE side should be transmitted in a 102ms period, which is a non-acquisition period because 102ms is not an argument of the total system subframe number 10240. .

17 is a diagram illustrating an example of a DRX operation to which the present invention is applied.

Referring to FIG. 17, the total system subframe number is 1024 * 10 = 10240 since the total system subframe number is "the maximum value of the System Frame Number (SFN * 10)". Therefore, wrap-around is applied every 10240 ms for the system subframe. That is, it is determined that 10240 ms has elapsed to 0 ms.

If the DRX cycle is 60ms, since 60 is not a factor of 10240, 40ms remain at the end after the DRX cycle is repeated (that is, 10240 = 60 * 17 + 40). If the DRX offset is 20ms, 20ms remain in the last part after the DRX cycle is repeated, and if wrap-around is performed, the DRX cycle ends at 40 (10220 + 60-10240) ms. This is equivalent to 40ms of DRX start offset after wrap-around application.

At this time, as the DRX start offset value is changed, the application time of the DRX cycle is changed based on the wrap-around.

If the application of the DRX cycle is to be maintained, the DRX cycle itself should be changed at the wrap-around time. For example, if the DRX start offset is to be maintained at 20 ms in FIG. 17, the DRX cycle at the wrap-around time point should be changed to 40 ms.

Accordingly, an enhanced DRX operation for performing DRX by appropriately changing the DRX start offset value for determining the start time of the DRX duration timer according to the present invention will be described.

As an example of the present invention, Equation 1 and Equation 2, which are conditions for determining the DRX start offset value associated with driving the DRX duration interval, are changed to Equation 3 to Equation 6 for enhanced DRX operation. That is, the DRX start offset value is calculated or updated based on Equations 3 to 6.

Equations 3 and 4 are applied when the long DRX cycle is determined to be divided by a short DRX cycle, and the following Equations 5 and 6 determine that the long DRX cycle is divided by a short DRX cycle. If it does not apply.

When the long DRX period is determined to be divided by the short DRX period, the DRX start offset value may be determined to satisfy the following Equation 3 when the long DRX period is used and to satisfy the following Equation 4 when the short DRX period is used. .

Here, wrap_arounded_drxStartOffset (k) is a wrap-around DRX start offset value indicating the start time of the DRX duration timer to which the k-th wrap-around is applied. K is also an integer and n is an integer. In addition, wrap_arounded_drxStartOfsset (0) is drxStartOffset which is the initial operation time of the duration timer.

The second equation in equations (3) and (4 in the wherein clause) is an equation that calculates the updated DRX start offset in every round, and the first equation is the duration at which the DRX cycle begins with the updated DRX start offset in the second equation. Calculate the start time of the interval timer.

That is, the position of (SFN * 10) + subframe number that satisfies the first expression indicates the start time of the duration timer in the corresponding round.

For example, if the previous wrap-around DRX start offset value (that is, the k-1th wrap-around DRX start offset value) is 20 and the DRX period is 60, the difference between 10240 and 20 is the DRX period, The value divided by 60 is 20. That is, 40 is insufficient in the DRX period, and the DRX operation is performed until the 20th subframe after the kth wraparound. Therefore, the kth wrap-around DRX start offset value is 40.

According to the present invention, the terminal or the base station (source base station or target base station) may determine the DRX start offset value to satisfy the equation (3) and the equation (4). In this case, although the DRX cycle is not a factor of 10240 (where 10240 is the total system subframe number), the UE and the base station may know the updated DRX start offset value every 10240 ms.

For example, suppose that the DRX duration timer is started and the terminal and the base station perform the DRX operation with the DRX start offset value as wrap_arounded_drxStartOffset (3) while the system frame is wrapped around the third frame. Since the DRX cycle is a non-argument cycle rather than an argument of 10240, the DRX start offset value will be changed to a wrap-arounded_drxStartOffset (4) which is different from before because the fourth wrap-around is applied later. In this case, the terminal and the base station may calculate (or update) a wrap-arounded_drxStartOffset (4) value, which is a DRX start offset value newly applied based on Equation 3 or Equation 4, respectively. That is, the terminal and the base station do not need to transfer the DRX start offset values with each wrap-around.

This is because Equations 3 and 4 are equations that are determined such that the wrap-around DRX start offset is recalculated so that the DRX cycle remains unchanged even after wrap-around. That is, the k-th wrap-around DRX start offset may be calculated by the terminal and the base station by itself based on the DRX start offset value when k-1.

Equations 3 and 4 are established when the long DRX cycle is an integer multiple of the short DRX cycle. Otherwise, the DRX offset determined based on the long DRX cycle does not apply to the short DRX cycle.

Therefore, as an example according to the present invention, the long DRX cycle and the short DRX cycle for the DRX operation may be determined such that the long DRX cycle is an integer multiple of the short DRX cycle.

On the other hand, when it is determined that the long DRX cycle is not divided by the short DRX cycle, the DRX start offset value satisfies Equation 5 when the long DRX cycle is used, and satisfies Equation 6 when the short DRX cycle is used. Can be determined.

When the DRX start offset value is determined to satisfy Equation 5 and Equation 6, the long DRX cycle is determined not to be divided by the short DRX cycle, and although the DRX cycle is not a factor of 10240, the UE and the base station are performed every 10240 ms. Can compute (or update) a new DRX start offset value by itself.

18 is a flowchart illustrating an example of a DRX operation according to the present invention. The start time (DRX start offset value) of the DRX duration interval timer determined to satisfy Equations 3 to 6 is applied. If the base station performing the DRX operation is changed from the source base station to the target base station due to the handover, the target base station can also calculate the DRX start offset value.

Referring to FIG. 18, the terminal performs IDC assistance information triggering (hereinafter referred to as IDC triggering) based on the IDC triggering condition (S1800). That is, it triggers the transmission of IDC assistance information. IDC triggering is performed when a situation in which coexistence interference occurs in a terminal device causes severe performance degradation or when a serious performance degradation is expected to occur soon (for example, within several hundred ms). The frequency at which deterioration or severe degradation is expected to occur soon is called an unusable frequency.

 For example, IDC triggering may be performed based on IDC on-going IDC of the terminal according to the determination within the terminal. That is, the IDC triggering condition may be whether IDC is in progress as described above with reference to FIG. 16, and a determination criterion may be based on a determination inside the terminal.

As another example, IDC triggering may be performed according to an internal implementation of the terminal as to whether or not the communication may be experienced by the IDC situation. In this case, the IDC triggering condition according to the internal determination of the UE may be set based on a test case, IDC interference strength and activity, a packet error rate, or a measurement result. Here, IDC activity refers to an indicator of how often IDC occurs in time. For example, IDC activity may be defined as a ratio of a subframe in which IDC does not occur and a subframe in which IDC occurs. As an example, there is a method of obtaining an average value based on each subframe weight.

Following step S1800, the terminal transmits IDC assistance information to the source base station (S1805). IDC assistance information is also called IDC indication information. In this case, the IDC assistance information may be transmitted together with a measurement result measured by the terminal.

The IDC support information may include unusable frequency band information for an FDM-based IDC solution or may include TDM pattern information for a TDM-based IDC solution. In particular, it may include information for DRX operation.

The IDC assistance information may include unusable frequency band information. The unusable frequency band may mean an IDC ongoing frequency band or may include a potential IDC capable frequency band as well as an IDC ongoing frequency band. .

For example, the IDC assistant information may include all EARFCN values of an unusable frequency band.

As another example, the IDC assistance information may include all EARFCN values of the unusable frequency band in the total frequency band set by the measurement report.

As another example, the IDC support information may include an EARFCN corresponding to the minimum threshold value, and based on this, a frequency band larger than the minimum threshold value within a band (operating band) in which the EARFCN is included is included. It may indicate that the frequency is unavailable. Alternatively, the IDC assistant information may include an EARFCN corresponding to the maximum boundary value, and indicate that a frequency band smaller than the maximum boundary value is an unusable frequency in a band (operation band) in which the corresponding EARFCN is included. can do. In this case, it is determined whether the EARFCN included in the IDC support information is the maximum boundary value or the minimum boundary value, or an indicator (boundary type indicator) indicating whether the EARFCN is the maximum boundary value or the minimum boundary value is the IDC support information. The type of the boundary value may be implicitly determined based on the number of operating bands to which the EARFCN belonging to or transmitted further included in the IDC support information.

As another example, the IDC assistance information may include an EARFCN corresponding to a boundary value of an unusable frequency band within the total frequency band determined by the measurement setup. The boundary value may be a maximum boundary value or a minimum boundary value in a band including the corresponding EARFCN value.

As another example, the IDC support information includes an EARFCN, and the EARFCN may indicate that an operating band region in which the EARFCN exists is an unusable frequency band.

As another example, when there are a plurality of operating bands affected by the frequency band indicated by the EARFCN, the IDC assistance information may indicate that all of the plurality of operating bands are unavailable frequency bands.

As another example, only the frequency bands related to the frequency bands set by the measurement setup among the IDC ongoing frequency bands may be signaled. For example, the EARFCN value of the frequency set by the measurement setup is 1,2,3,4,5, the EARFCN value of the IDC ongoing frequency band is less than or equal to 3 (ie, the maximum threshold value is 3), and is greater than 10 If greater than or equal to (ie, minimum boundary value is 10), only the maximum boundary value 3 may be signaled by the terminal. This is because the minimum threshold value 10 is outside the current measurement set frequency band (1, 2, 3, 4, 5), and the threshold value can be determined only within the frequency set by the measurement setting. As another example, all EARFCN values (1, 2, 3) of the frequency band set by the measurement setup among the IDC ongoing frequency bands may be signaled.

The IDC assistance information may include TDM pattern information. Values related to DRX parameters for performing a DRX operation may be recommended and transmitted through the TDM pattern information. For example, DRX period, DRX activity interval values may be transmitted, or DRX period, duration interval timer, DRX subframe offset, DRX start offset values may be transmitted. The unit of the DRX period, the DRX subframe offset, and the DRX start offset may be a subframe, a duration timer may also be given in subframe units, and the duration timer may be given in PDCCH-subframe units.

In addition, the IDC assistance information may include DRX pattern information or HARQ based reservation bitmap pattern information. In this case, the DRX pattern may include a DRX period and a scheduled period value, and may further include a DRX start offset value. Here, the DRX start offset value may indicate a time point at which the duration timer of the DRX cycle operates. The DRX start offset value is determined based on the system frame number (SFN) 0 and the subframe number 0, and may be in a subframe (or system frame) unit.

For example, the DRX start offset value may mean a time offset between WLAN and LTE for protection of periodic beacon transmission in a wireless local area network (WLAN).

In addition, the HARQ based reservation bitmap pattern refers to subframes in which LTE transmission and reception are allowed in consideration of transmission timings of LTE HARQ processes.

Meanwhile, the TDM pattern information may be information that is equally applied to all unusable frequency bands per terminal.

As another example, the TDM pattern information may be information that is equally applied to a serving frequency for which one UE receives a service.

As another example, the TDM pattern information may include one TDM pattern information applied to the serving frequency and one TDM pattern information applied to the non-serving frequency. However, the TDM pattern for the non-serving frequency may be selectively transmitted according to the determination of the terminal (or base station).

As another example, TDM pattern information may be independently recommended and transmitted for each of frequency bands defined in an unusable frequency band. For example, if the measured EARFCN value of the set frequency is 1,2,3,4,5 and the maximum boundary value of the EARFCN value of the frequency affected by IDC is 3, the EARFCN value of the unusable frequency band is 1,2 , 3, and DRX parameters are signaled for each unusable frequency band. Additional signaling is also possible to represent the relationship between each unusable frequency band and the TDM pattern (or DRX parameter) for the corresponding signaling. For example, signaling indicating the number of EARFCN values of the unusable frequency band may be added, and the total number of TDM patterns may be known through the number of EARFCN values of the unusable frequency band. In signaling indicating the number of EARFCN values of the unusable frequency band, the TDM pattern may be mapped in order of increasing EARFCN value of the unusable frequency band. For example, when 2, 3, 6, and 7 are signaled as EARFCN values of an unusable frequency band and four TDM patterns are signaled (pattern 1, pattern 2, pattern 3, and pattern 4), the TDM pattern is signaled. In order, they may be mapped to EARFCN values 2, 3, 6, and 7, respectively. That is, TDM pattern 1 is mapped to EARFCN value 2, TDM pattern 2 is mapped to EARFCN value 3, TDM pattern 3 is mapped to EARFCN value 6, and TDM pattern 4 is mapped to EARFCN value 7. Alternatively, in signaling indicating the number of EARFCN values of the unusable frequency band, each of the EARFCN values of the unusable frequency band and the TDM pattern may be directly mapped. That is, when the TDM pattern is signaled, the EARFCN value mapped to each TDM pattern is simultaneously signaled. If an unusable frequency band is directly expressed as an EARFCN value, a TDM pattern may be paired to each EARFCN value to be simultaneously signaled. If an unusable frequency band is represented by a threshold, additional signaling for each of the EARFCN values is possible.

On the other hand, the IDC assistance information may include information about the type and type of another communication system capable of generating IDC in the terminal. The type information of the other communication system may be at least one of WLAN, BT or GNSS. The type information of another communication system may be at least one of a voice communication type, a streaming service type such as a multimedia VOD, or an offload type. The scope of the present invention is not limited thereto, and may include the type and type information of various communication systems.

After the step S1805, the base station selects the most appropriate IDC solution (IDC solution, or IDC coordination scheme) based on the IDC assistance information received from the terminal and transmits it to the terminal by including it in the RRC connection reconfiguration message. (S1810). In this case, when the measurement result is not received together with the IDC assistance information, the TDM IDC operation may be selected (selected or determined) as the IDC solution.

If the TDM IDC operation is configured, an enhanced DRX operation based on Equations 3 to 6 may be performed at the UE and the base station, and the DRX start offset value is calculated based on Equations 3 to 6 It may be a wrapped-around DRX start offset (wrap_arounded_drxStartoffset).

The terminal performs the measurement and reports the measurement result to the base station (S1815). In this case, the transmitted measurement report is a measurement result in which the influence of IDC interference is removed. The specific IDC interference effect may be removed according to the implementation of the terminal.

19 is a diagram illustrating an example of a method of obtaining a measured value with the IDC influence removed according to the present invention.

Referring to FIG. 19, IDC is generated due to ISM transmission for LTE DL reception of a terminal. The IDC generation interval 1900 is measurement samples that are removed in a filtering process in which the UE derives a measurement result from all measurement samples. The UE calculates a measurement value based on the remaining measurement samples except for the IDC generation interval 1900.

The measured value can be calculated using Equation 7 below.

Referring to Equation 7, M _n is the most recent measurement sample, F _n is the measurement to be reported by the measurement report, F _{n -1} is the measurement reported by the previous measurement report, and a is 1 / 2 (k / 4), where k is the filter coefficient used for filtering.

The measurement sample is a measurement value in units of subframes, and is a variable required to derive the measurement result to be reported by the measurement report.

Or, the measurement sample means a measurement value for the subframe selected by the rule defined in the wireless system among the measurement values for all the subframes received by the terminal.

The measurement sample may be obtained at the physical layer of the terminal, and filtering may be performed at an upper layer of the terminal, for example, a radio resource control (RRC) layer.

The measurement sample may be acquired continuously every subframe, but may be obtained discontinuously as long as the capacity of the terminal or a condition defined by the system is satisfied. That is, another measurement sample may be obtained after a predetermined interval of time after one measurement sample is obtained. In this case, measurement samples are not obtained for some subframes. The spacing section may be periodic or aperiodic.

For example, in order to obtain a measurement sample having no IDC influence on the IDC generation interval 1900, an autonomously denial may be performed for a communication system generating IDC interference in the terminal. For example, for measurement of the LTE band, the measurement sample is arbitrarily rejected for ISM transmission.

Similar to an arbitrary rejection scheme, it is also possible to reduce the ISM transmit power. By significantly reducing the transmit power, the impact of IDC can be reduced.

As another example, in order to obtain a measurement sample having no IDC influence on the IDC generation interval 1900, there is a method of measuring the IDC interference strength in the terminal for the measurement samples having the IDC influence and calculating it in consideration of this. That is, only IDC interference magnitudes are removed from IDC-affected measurement samples.

First, a measurement sample having an influence of IDC in a serving cell or a neighbor cell obtained based on RSRQ is conceptually expressed by Equation 8 below.

Where S is the strength of the received signal through the serving cell, I is the strength of the interference signal (e.g., inter-cell interference) acting on the system, N is the strength of the noise (e.g., thermal noise), I 'is the strength of IDC. The measurement sample refers to a relative ratio of IDC and inter-cell interference of the received signal.

According to the present invention, a method of eliminating IDC interference in a measurement sample is as follows.

In this case, the I 'value can be obtained by different methods according to the implementation in the terminal, and by removing the I' value, a measurement sample without the influence of I 'can be obtained.

As another example, in order to obtain a measurement sample having no IDC influence on the IDC generation interval 1900, when average number of IDC influenced samples is smaller than a predetermined reference value, the influence of the IDC influenced measurement samples may be determined by average filtering alone. Can be removed. In this case, a measurement sample having no IDC influence may be obtained according to Equation 8.

On the other hand, following step S1815, the source base station performs a handover decision based on the measurement report (S1820). For example, it may be determined to perform a handover to a target base station operating in an unusable frequency domain under the influence of IDC interference.

Following step S1820, the source base station transmits a handover request to the target base station (S1825). In this case, the handover request message may be transmitted from the source base station to the target base station, and the handover request message may include a TDM pattern. The handover request message may be transmitted through an X2 interface (or S1 interface).

According to an embodiment of the present invention, the TDM pattern is updated DRX start offset information (wrap-around DRX start offset) at the source base station so that the enhanced DRX operation is seamlessly applied during the handover procedure according to the present invention. Value). The source base station may be a wrap-around DRX start offset value calculated based on Equations 3 to 6.

That is, the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) calculated by the source base station at the time when the handover request message is transmitted is included in the handover request message and transmitted to the target base station. Through Equations 3 to 6, the last updated wrap-around DRX start offset value is transmitted through the application of several wrap-arounds.

In another embodiment of the present invention, the absolute time measured at the source base station at the time when the handover request message is transmitted is included in the handover request message along with the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) to be transmitted to the target base station. Can be. The measured absolute time may be used as information for estimating a state variation of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the target base station. For example, the measured absolute time may be in the form of "AM12: 00: 00".

If the time synchronization between the source base station and the target base station (eg, subframe synchronization) is not correct, the synchronization may be performed based on the measured absolute time.

If a delay occurs in a network and a subframe loss occurs, the delayed portion may be adjusted based on the measured absolute time.

The target base station may determine a time gap between the source base station and the target base station based on the measured absolute time. A wrap-around DRX start offset may be adjusted based on the time gap.

Subsequently to step S1825, the target base station transmits a handover request acknowledgement to the source base station in order to accept the handover request (S1830). In this case, the handover request confirmation message may be transmitted from the target base station to the source base station. The handover request confirmation message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the handover request confirmation message may include a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated by a target base station in relation to an enhanced DRX operation. Based on Equations 3 to 6, the DRX start offset value wrapped around the target base station may be updated again.

In another embodiment of the present invention, the absolute time measured at the target base station (or the absolute time measured at the source base station) at the time when the handover request confirmation message is transmitted is the wrap-around DRX start offset value (wrap_arounded_drxStartOffset). ) May be included in the handover request confirmation message and delivered to the source base station. The measured absolute time may be used as information for estimating the state transition of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the source base station.

In another embodiment of the present invention, the handover request confirmation message may not include an information element for enhanced DRX operation.

Following step S1830, the source base station transmits a handover command to the terminal (S1835). The handover command may be transmitted through an RRC connection reconfiguration, and an RRC connection reconfiguration message may be transmitted from a source base station to a terminal. A DRX pattern recommended by the source base station is transmitted through the handover command.

According to an embodiment of the present invention, the handover command may include a DRX configuration configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted at the handover request (S1825).

According to another embodiment of the present invention, when the source base station receives the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated at the target base station through the handover request confirmation, the handover command is the recomputed wrap-around. It may include a DRX configuration configured by applying the specified DRX start offset value (wrap_arounded_drxStartOffset).

According to another embodiment of the present invention, when the source base station receives an absolute time and a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) that is recalculated at the target base station through the handover request confirmation, the handover command may transmit corresponding information. And a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated at the source base station.

After step S1835, the terminal connected to the target base station performs an enhanced DRX operation based on the handover command (S1840). The DRX operation may be performed in the unusable frequency domain due to the influence of IDC interference, and the DRX operation may be performed based on the DRX configuration received through the handover command. The DRX operation is not necessarily performed based on the DRX configuration recommended by the source base station, and the DRX operation may be performed based on the DRX configuration set by the terminal or the updated DRX configuration by the terminal.

The UE may perform a DRX operation based on the DRX setting included in the handover command, wherein the DRX setting is based on a wrap-around DRX start offset value calculated based on Equations 3 to 6 The wrap-around DRX start offset may be a value calculated at the source base station or a value calculated at the target base station again.

Subsequently to step S1840, if the UE determines that the wrap-around DRX start offset value received through the DRX setting when receiving the handover command is an offset value unsuitable for TDM IDC operation (eg, DRX operation). In case, the terminal transmits IDC assistance information to the target base station (S1845).

For example, a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) may be distorted due to delay in handover, asynchronous system frames between the source base station and the target base station, and at this time, wrap-around DRX start offset value may be inappropriate for TDM IDC operation.

As another example, if the DRX start offset value updated through the wrap-around and the DRX start offset value received through the handover command are not synchronized, the terminal may transmit additional IDC assistance information to the target base station.

The IDC assistance information may be transmitted through an RRC connection reset (for example, through an RRC connection reset message), or transmitted in the form of IDC support information used in S1805 after an RRC connection reset is finished, or random access (random). access) may be included in the RRC connection reset complete message transmitted in the procedure (for example, may be transmitted in the form of an information element of the RRC connection reset message).

The target base station may recalculate a wrap-around DRX start offset value based on Equation 3 to Equation 6 through the IDC assistant information. If the DRX configuration is reconfigured based on this, the UE may perform a DRX operation based on the DRX configuration.

20 is a flowchart illustrating another example of a DRX operation according to the present invention. The start time (DRX start offset value) of the DRX duration interval timer determined to satisfy Equations 3 to 6 is applied.

Referring to FIG. 20, the terminal performs IDC assistance information triggering (hereinafter referred to as IDC triggering) based on the IDC triggering condition (S2000). That is, it triggers the transmission of IDC assistance information. IDC triggering is performed when coexistence interference in a terminal device occurs and a performance degradation due to interference inside the terminal is severe, or when a serious performance degradation is expected to occur soon (for example, within several hundred ms). The frequency at which deterioration or severe degradation is expected to occur soon is called an unusable frequency.

 For example, IDC triggering may be performed based on whether IDC is in progress in the terminal according to the determination within the terminal. As another example, IDC triggering may be performed according to an internal determination of the UE as to whether or not the communication may be experienced by the IDC situation.

After step S2000, the terminal transmits IDC assistance information to the source base station (S2005). IDC assistance information is also called IDC indication information. In this case, the IDC assistance information may be transmitted together with the measurement result measured by the terminal.

The IDC support information may include unusable frequency band information for the FDM-based IDC solution or may include TDM pattern information for the TDM-based IDC solution. In particular, it may include DRX related information for DRX operation.

The IDC assistance information may include TDM pattern information. Values related to DRX parameters for performing a DRX operation may be recommended and transmitted through the TDM pattern information. For example, DRX period, DRX activity interval values may be transmitted, or DRX period, duration interval timer, DRX subframe offset, DRX start offset values may be transmitted. The unit of the DRX period, the DRX start offset, and the DRX subframe offset may be a subframe, a duration timer may also be given in subframe units, and the duration timer may be given in PDCCH-subframe units.

In addition, the IDC assistance information may include DRX pattern information or HARQ based reservation bitmap pattern information as information for correct DRX operation for IDC. In this case, the DRX pattern may include a DRX cycle and a scheduled cycle value, and may further include a DRX start offset value. Here, the DRX start offset value may mean a time point at which the duration timer of the DRX cycle operates. The DRX start offset value is determined based on the system frame number (SFN) 0 and the subframe number 0, and may be in a subframe (or system frame) unit. For example, the DRX start offset value may mean a time offset between WLAN and LTE for protection of periodic beacon transmission in the WLAN. In addition, the HARQ based reservation bitmap pattern refers to subframes in which LTE transmission and reception are allowed in consideration of transmission timings of LTE HARQ processes.

For example, the TDM pattern information may be information that is equally applied to all unusable frequency bands per one terminal.

As another example, the TDM pattern information may be information that is equally applied to a serving frequency for which one UE receives a service.

As another example, the TDM pattern information may include one TDM pattern information applied to the serving frequency and one TDM pattern information applied to the non-serving frequency. However, the TDM pattern for the non-serving frequency may be selectively transmitted according to the determination of the terminal (or base station).

As another example, TDM pattern information may be independently recommended and transmitted for each of frequency bands defined in an unusable frequency band.

On the other hand, the IDC assistance information may include information about the type and type of another communication system capable of generating IDC in the terminal. The type information of the other communication system may be at least one of WLAN, BT or GNSS. The type information of another communication system may be at least one of a voice communication type, a streaming service type such as a multimedia VOD, or an offload type. The scope of the present invention is not limited thereto, and may include the type and type information of various communication systems.

After the step S2005, the source base station selects the most appropriate IDC solution (or IDC adjustment method) based on the IDC assistance information received from the terminal and transmits it to the terminal by including it in the RRC connection reconfiguration message (S2010). In this case, when the measurement result is not received together with the IDC support information, a TDM IDC operation may be selected (or determined) and transmitted to the IDC solution.

If the TDM IDC operation is configured, the enhanced DRX operation may be performed in the terminal and the base station according to the present invention based on Equation 3 to Equation 6, and the DRX start offset value is represented by Equation 3 to Equation 6 below. It may be a wrap-around DRX start offset (wrap_arounded_drxStartoffset) calculated based on.

The terminal performs the measurement and reports the measurement result to the base station (S2015). In this case, the transmitted measurement report is a measurement result in which the influence of IDC interference is removed. The specific IDC interference effect may be removed according to the implementation of the terminal.

On the other hand, after step S2015, the source base station performs a handover decision based on the measurement report (S2020). For example, a handover may be determined to a target base station operating in an unusable frequency domain under the influence of IDC interference.

Following step S2020, the source base station transmits a handover request to the target base station (S2025). In this case, the handover request message may be transmitted from the source base station to the target base station, and the handover request message may include a TDM pattern. The handover request message may be transmitted through an X2 interface (or S1 interface).

Following step S2025, the target base station transmits a handover request confirmation to the source base station in order to accept the handover request (S2030). In this case, the handover request confirmation message may be transmitted from the target base station to the source base station. The handover request confirmation message may be transmitted through an X2 interface (or S1 interface).

Following step S2030, the source base station transmits a handover command to the terminal (S2035). The handover command may be transmitted through an RRC connection reconfiguration, and an RRC connection reconfiguration message may be transmitted from a source base station to a terminal. The DRX pattern recommended by the source base station is transmitted through the handover command.

According to an embodiment of the present invention, the handover command may include updated DRX start offset information (wrap-around DRX start offset value). This may be a wrap-around DRX start offset value calculated based on Equations 3 to 6.

That is, the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) calculated by the source base station at the time when the handover command is transmitted is included in the handover command and transmitted to the terminal. Through Equations 3 to 6, the last updated wrap-around DRX start offset value is transmitted through the application of several wrap-arounds.

According to another embodiment of the present invention, the absolute time measured by the source base station at the time when the handover command is transmitted may be included in the handover command together with the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) and transmitted to the terminal. The measured absolute time may be used as information for estimating a state transition of a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) in the terminal. For example, the measured absolute time may be in the form of "AM12: 00: 00".

If the time synchronization between the source base station and the terminal (eg, subframe synchronization) is not correct, the synchronization may be performed based on the measured absolute time.

If a delay occurs in a network and subframe loss occurs, the delayed portion may be adjusted based on the measured absolute time.

The terminal may determine a time gap between the source base station and the terminal based on the measured absolute time. A wrap-around DRX start offset may be adjusted based on the time gap.

Subsequent to step S2035, the UE must be IDC regardless of whether the wrap-around DRX start offset value received through the DRX configuration is suitable for performing a TDM IDC operation (eg, a DRX operation) if the handover command is received. The assistance information is transmitted to the target base station (S2040). That is, during the handover or after the end of the handover, the terminal necessarily transmits the wrap-around DRX start offset value to the target base station once again.

The IDC assistance information may be transmitted through an RRC connection reset (eg, through an RRC connection reset message), or transmitted in the form of IDC support information used in S2005 after an RRC connection reset is finished, or in a random access procedure. It may be included in the transmitted RRC connection reconfiguration complete message (for example, may be transmitted in the form of an information element of the RRC connection reestablishment message).

The target base station may recalculate a wrap-around DRX start offset value based on Equation 3 to Equation 6 through the IDC assistant information. If the DRX configuration is reconfigured based on this, the terminal may perform a DRX operation based on the DRX configuration (S2045).

21 is a flowchart illustrating still another example of a DRX operation according to the present invention. An embodiment in which DRX operation is applied in an enhanced diversity data application (EDDA).

Referring to FIG. 21, the base station transmits an RRC connection reconfiguration to the terminal (S2100). In the RRC connection reconfiguration, a TDM IDC operation may be transmitted or an EDDA operation may be transmitted. The RRC connection reestablishment message may be an EDDA message or may include related information elements.

If the TDM IDC operation or the EDDA operation is configured, the DRX start offset value may be a wrap-around DRX start offset calculated by the terminal or the base station based on Equation 3 to Equation 6.

The terminal performs the measurement and reports the measurement result to the base station (S2105). In this case, the transmitted measurement report may be a measurement result in which the influence of the IDC interference is removed, and specific removal of the influence of the IDC interference may depend on the implementation of the terminal.

On the other hand, following step S2105, the source base station performs a handover decision based on the measurement report (S2110). For example, a handover may be determined to a target base station operating in an unusable frequency domain under the influence of IDC interference.

Following step S2110, the source base station transmits a handover request to the target base station (S2115). In this case, the handover request message may be transmitted from the source base station to the target base station, and the handover request message may include a TDM pattern. The handover request message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the TDM pattern may include updated DRX start offset information (wrap-around DRX start offset value) in order to seamlessly apply the enhanced DRX operation during the handover procedure according to the present invention. have. It may be a wrap-around DRX start offset value calculated based on Equations 3 to 6.

That is, the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) calculated by the source base station at the time when the handover request message is transmitted is included in the handover request message and transmitted to the target base station. Through Equations 3 to 6, the last updated wrap-around DRX start offset value is transmitted through the application of several wrap-arounds.

In another embodiment of the present invention, the absolute time measured at the source base station at the time when the handover request message is transmitted is included in the handover request message along with the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) to be transmitted to the target base station. Can be. The measured absolute time may be used as information for estimating a state variation of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the target base station. For example, the measured absolute time may be in the form of "AM12: 00: 00".

If the time synchronization between the source base station and the target base station (eg, subframe synchronization) is not correct, the synchronization may be performed based on the measured absolute time.

If a delay occurs in a network and subframe loss occurs, the delayed portion may be adjusted based on the measured absolute time.

The target base station may determine a time gap between the source base station and the target base station based on the measured absolute time. A wrap-around DRX start offset may be adjusted based on the time gap.

Following step S2115, the target base station transmits a handover request confirmation to the source base station in order to accept the handover request (S2120). In this case, the handover request confirmation message may be transmitted from the target base station to the source base station. The handover request confirmation message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the handover request confirmation message may include a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated by a target base station in relation to an enhanced DRX operation. Based on Equations 3 to 6, the DRX start offset value wrapped around the target base station may be updated again.

In another embodiment of the present invention, the absolute time measured by the target base station at the time when the handover request confirmation message is transmitted is included in the handover request confirmation message together with the re-calculated wrap-around DRX start offset value (wrap_arounded_drxStartOffset). It may be included and delivered to the source base station. The measured absolute time may be used as information for estimating the state transition of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the source base station.

In another embodiment of the present invention, the handover request confirmation message may not include an information element for enhanced DRX operation.

Following step S2120, the source base station transmits a handover command to the terminal (S2125). The handover command may be transmitted through an RRC connection reconfiguration, and an RRC connection reconfiguration message may be transmitted from a source base station to a terminal. The handover command transmits a DRX configuration, such as a DRX pattern recommended by the source base station.

According to an embodiment of the present invention, the handover command may include updated DRX start offset information (wrap-around DRX start offset value). It may be a wrap-around DRX start offset value calculated at the source base station based on Equation 3 to Equation 6.

That is, the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) calculated by the source base station at the time when the handover command is transmitted is included in the handover command and transmitted to the terminal. Through Equations 3 to 6, the last updated wrap-around DRX start offset value is transmitted through the application of several wrap-arounds.

According to another embodiment of the present invention, the absolute time measured by the source base station at the time when the handover command is transmitted may be included in the handover command together with the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) and transmitted to the terminal. The measured absolute time may be used as information for estimating a state transition of a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) in the terminal. For example, the measured absolute time may be in the form of "AM12: 00: 00".

If the time synchronization between the source base station and the terminal (eg, subframe synchronization) is not correct, the synchronization may be performed based on the measured absolute time.

If a delay occurs in a network and subframe loss occurs, the delayed portion may be adjusted based on the measured absolute time.

The terminal may determine a time gap between the source base station and the terminal based on the measured absolute time. A wrap-around DRX start offset may be adjusted based on the time gap.

Following step S2125, the terminal may perform a DRX operation on a target base station based on the DRX setting (S2130).

Subsequently to step S2130, if the handover command receives the wrap-around DRX start offset value received through the DRX setting, the UE is said to be an offset value that is not suitable for TDM IDC operation (eg, DRX operation) or EDDA operation. If this is determined, the terminal transmits a new message to the target base station (S2130). The new message may be an IDC assistant information message or an EDDA message.

For example, a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) may be distorted due to delay in handover, asynchronous system frames between the source base station and the target base station, and at this time, wrap-around DRX start The offset value may not be suitable for TDM IDC operation.

For another example, if the DRX start offset value updated through the wrap-around and the DRX start offset value received through the handover command do not match, the terminal may transmit a new message to the target base station.

The new message may be transmitted through an RRC connection reset (for example, through an RRC connection reset message), in the form of IDC support information after an RRC connection reset is finished, or an RRC connection reset transmitted in a random access procedure. It may be included in the completion message and transmitted (for example, may be transmitted in the form of an information element of the RRC connection reestablishment message).

22 is a flowchart illustrating an example of an operation of a terminal performing a DRX operation according to the present invention.

Referring to FIG. 22, the terminal performs IDC assistance information triggering (hereinafter referred to as IDC triggering) based on the IDC triggering condition (S2200). That is, it triggers the transmission of IDC assistance information. IDC triggering is performed when coexistence interference in a terminal device occurs and a performance degradation due to interference inside the terminal is severe, or when a serious performance degradation is expected to occur soon (for example, within several hundred ms).

For example, IDC triggering may be performed based on IDC on-going IDC of the terminal according to the determination within the terminal. That is, the IDC triggering condition may be whether IDC is in progress as described above with reference to FIG. 16, and a determination criterion may be based on a determination inside the terminal.

As another example, IDC triggering may be performed according to an internal implementation of the terminal as to whether or not the communication may be experienced by the IDC situation.

Following step S2200, the terminal transmits IDC assistance information to the source base station (S2205). In this case, the IDC assistance information may be transmitted together with the measurement result measured by the terminal.

The IDC support information may include unusable frequency band information for the FDM-based IDC solution or may include TDM pattern information for the TDM-based IDC solution. In particular, it may include DRX related information for the DRX operation according to the present invention.

The IDC assistance information may include TDM pattern information. Values related to DRX parameters for performing a DRX operation may be recommended and transmitted through the TDM pattern information. For example, the DRX period, the DRX activity interval values may be transmitted, or the DRX period, the duration interval timer, the DRX subframe offset value, and the DRX period start offset value may be transmitted. The unit of the DRX period and the DRX subframe offset and the DRX period start offset may be a subframe, a duration timer may also be given in subframe units, and the duration timer may be given in PDCCH-subframe units.

In addition, the IDC assistance information may include DRX pattern information or HARQ based reservation bitmap pattern information as information for correct DRX operation for IDC. In this case, the DRX pattern may include a DRX cycle and a scheduled cycle value, and may further include a DRX start offset value. Here, the DRX start offset value may mean a time point at which the duration timer of the DRX cycle operates. The DRX start offset value is determined based on the system frame number (SFN) 0 and the subframe number 0, and may be in a subframe (or system frame) unit. For example, the DRX start offset value may mean a time offset between WLAN and LTE for protection of periodic beacon transmission in the WLAN. In addition, the HARQ based reservation bitmap pattern refers to subframes in which LTE transmission and reception are allowed in consideration of transmission timings of LTE HARQ processes.

For example, the TDM pattern information may be information that is equally applied to all unusable frequency bands per one terminal.

As another example, the TDM pattern information may be information that is equally applied to a serving frequency for which one UE receives a service.

As another example, the TDM pattern information may include one TDM pattern information applied to the serving frequency and one TDM pattern information applied to the non-serving frequency. However, the TDM pattern for the non-serving frequency may be selectively transmitted according to the determination of the terminal (or base station).

As another example, TDM pattern information may be independently recommended and transmitted for each of frequency bands defined in an unusable frequency band.

On the other hand, the IDC assistance information may include information about the type and type of another communication system capable of generating IDC in the terminal. The type information of the other communication system may be at least one of WLAN, BT or GNSS. The type information of another communication system may be at least one of a voice communication type, a streaming service type such as a multimedia VOD, or an offload type. The scope of the present invention is not limited thereto, and may include the type and type information of various communication systems.

Subsequently to step S2205, the terminal receives an RRC connection reconfiguration message including an IDC solution selected by the base station based on the IDC assistance information (S2210). In this case, when the measurement result is not received together with the IDC assistant information, a TDM IDC operation may be transmitted to the IDC solution.

If the TDM IDC operation is configured, the enhanced DRX operation may be performed in the terminal and the base station according to the present invention based on Equation 3 to Equation 6, and the DRX start offset value is represented by Equation 3 to Equation 6 below. It may be a wrap-around DRX start offset (wrap_arounded_drxStartoffset) calculated based on.

The terminal performs the measurement and reports the measurement result to the base station (S2215). In this case, the transmitted measurement report is a measurement result in which the influence of IDC interference is removed. The specific IDC interference effect may be removed according to the implementation of the terminal.

Subsequently to step S2215, the terminal receives a handover command from the source base station (S2220). The handover command may be transmitted through an RRC connection reconfiguration, and an RRC connection reconfiguration message may be transmitted from a source base station to a terminal. The DRX pattern recommended by the source base station is transmitted through the handover command.

According to an embodiment of the present invention, the handover command may include a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted when a handover request is made.

According to another embodiment of the present invention, when the source base station receives the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated at the target base station through the handover request confirmation, the handover command is the recomputed wrap-around It may include a DRX configuration configured by applying the specified DRX start offset value (wrap_arounded_drxStartOffset).

After step S2220, the terminal connected to the target base station performs an enhanced DRX operation based on the handover command (S2225). The target base station may also perform a DRX operation operating in the unusable frequency domain under the influence of IDC interference, and the DRX operation may be performed based on the DRX configuration received through the handover command. The DRX operation is not necessarily performed based on the DRX configuration recommended by the source base station through the handover command, and the DRX operation may be performed based on the DRX configuration set by the UE or the updated DRX configuration by the UE.

The UE may perform a DRX operation based on the DRX setting included in the handover command, wherein the DRX setting may be a wrap-around DRX start offset value calculated based on Equations 3 to 6, and The wrap-around DRX start offset may be a value calculated at the source base station or a value calculated at the target base station again.

Subsequently to step S2225, if the UE determines that the wrap-around DRX start offset value received through the DRX setting when receiving the handover command is an offset value unsuitable for performing a TDM IDC operation (eg, a DRX operation). In case, the terminal transmits the IDC assistance information to the target base station (S2230).

For example, a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) may be distorted due to delay in handover, asynchronous system frames between the source base station and the target base station, and at this time, wrap-around DRX start offset value may be inappropriate for TDM IDC operation.

For another example, if the DRX start offset value updated through the wrap-around and the DRX start offset value received through the handover command do not match, the terminal may transmit additional IDC assistance information to the target base station. .

The IDC assistance information may be transmitted through an RRC connection reset (for example, through an RRC connection reset message), or transmitted in the form of IDC support information used in S2205 after the RRC connection reset is finished, or random access (random). access) may be included in the RRC connection reset complete message transmitted in the procedure (for example, may be transmitted in the form of an information element of the RRC connection reset message).

The target base station may recalculate a wrap-around DRX start offset value based on Equation 3 to Equation 6 through the IDC assistant information. If the DRX configuration is reconfigured based on this, the UE may perform a DRX operation based on the DRX configuration.

23 is a flowchart illustrating an example of an operation of a base station performing a DRX operation according to the present invention. It corresponds to the operation of the source base station in performing the handover from the source base station to the target base station.

Referring to FIG. 23, the source base station receives IDC assistance information from the terminal (S2300). In this case, the IDC assistance information may be transmitted together with the measurement result measured by the terminal.

The IDC support information may include unusable frequency band information for the FDM-based IDC solution or may include TDM pattern information for the TDM-based IDC solution. In particular, it may include DRX related information for the DRX operation according to the present invention.

The IDC assistance information may include TDM pattern information. Values related to DRX parameters for performing a DRX operation may be recommended and transmitted through the TDM pattern information. For example, the DRX period, the DRX activity interval values may be transmitted, or the DRX period, the duration interval timer, the DRX subframe offset value, and the DRX period start offset values may be transmitted. The unit of the DRX period, the DRX period start offset value, and the DRX subframe offset may be a subframe, a duration timer may also be given in subframe units, and the duration timer may be given in PDCCH-subframe units.

In addition, the IDC assistance information may include DRX pattern information or HARQ based reservation bitmap pattern information as information for correct DRX operation for IDC. In this case, the DRX pattern may include a DRX cycle and a scheduled cycle value, and may further include a DRX start offset value. Here, the DRX start offset value may mean a time point at which the duration timer of the DRX cycle operates. The DRX start offset value is determined based on the system frame number (SFN) 0 and the subframe number 0, and may be in a subframe (or system frame) unit. For example, the DRX start offset value may mean a time offset between WLAN and LTE for protection of periodic beacon transmission in the WLAN. In addition, the HARQ based reservation bitmap pattern refers to subframes in which LTE transmission and reception are allowed in consideration of transmission timings of LTE HARQ processes.

For example, the TDM pattern information may be information that is equally applied to all unusable frequency bands per one terminal.

As another example, the TDM pattern information may be information that is equally applied to a serving frequency for which one UE receives a service.

As another example, the TDM pattern information may include one TDM pattern information applied to the serving frequency and one TDM pattern information applied to the non-serving frequency. However, the TDM pattern for the non-serving frequency may be selectively transmitted according to the determination of the terminal (or base station).

As another example, TDM pattern information may be independently recommended and transmitted for each of frequency bands defined in an unusable frequency band.

On the other hand, the IDC assistance information may include information about the type and type of another communication system capable of generating IDC in the terminal. The type information of the other communication system may be at least one of WLAN, BT or GNSS. The type information of another communication system may be at least one of a voice communication type, a streaming service type such as a multimedia VOD, or an offload type. The scope of the present invention is not limited thereto, and may include the type and type information of various communication systems.

After the step S2300, the source base station selects the most appropriate IDC solution (or IDC control method) based on the IDC support information received from the terminal and transmits it to the terminal by including it in the RRC connection reconfiguration message (S2305).

In this case, when the measurement result is not received together with the IDC assistant information, a TDM IDC operation may be transmitted to the IDC solution.

If the TDM IDC operation is configured, the enhanced DRX operation may be performed in the terminal and the base station according to the present invention based on Equation 3 to Equation 6, and the DRX start offset value is represented by Equation 3 to Equation 6 below. It may be a wrap-around DRX start offset (wrap_arounded_drxStartoffset) calculated based on.

Subsequently to step S2305, the source base station receives a result of the terminal performing the measurement from the terminal (S2310). In this case, the transmitted measurement report is a measurement result in which the influence of IDC interference is removed. The specific IDC interference effect may be removed according to the implementation of the terminal.

On the other hand, after step S2310, the source base station performs a handover decision based on the measurement report (S2315). For example, a handover may be determined to a target base station operating in an unusable frequency domain under the influence of IDC interference.

Following step S2315, the source base station transmits a handover request to the target base station (S2320). In this case, the handover request message may be transmitted from the source base station to the target base station, and the handover request message may include a TDM pattern. The handover request message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the TDM pattern may include updated DRX start offset information (wrap-around DRX start offset value) in order to seamlessly apply the enhanced DRX operation during the handover procedure according to the present invention. have. It may be a wrap-around DRX start offset value calculated based on Equations 3 to 6.

That is, the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) calculated by the source base station at the time when the handover request message is transmitted is included in the handover request message and transmitted to the target base station. Through Equations 3 to 6, the last updated wrap-around DRX start offset value is transmitted through the application of several wrap-arounds.

In another embodiment of the present invention, the absolute time measured at the source base station at the time when the handover request message is transmitted is included in the handover request message along with the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) to be transmitted to the target base station. Can be. The measured absolute time may be used as information for estimating a state variation of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the target base station. For example, the measured absolute time may be in the form of "AM12: 00: 00".

If the time synchronization between the source base station and the target base station (eg, subframe synchronization) is not correct, the synchronization may be performed based on the measured absolute time.

If a delay occurs in a network and subframe loss occurs, the delayed portion may be adjusted based on the measured absolute time.

The target base station may determine a time gap between the source base station and the target base station based on the measured absolute time. A wrap-around DRX start offset may be adjusted based on the time gap.

Following step S2320, the source base station receives a handover request confirmation from the target base station to accept the handover request (S2325). In this case, the handover request confirmation message may be transmitted from the target base station to the source base station. The handover request confirmation message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the handover request confirmation message may include a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated by a target base station in relation to an enhanced DRX operation. Based on Equations 3 to 6, the DRX start offset value wrapped around the target base station may be updated again.

In another embodiment of the present invention, the absolute time measured by the target base station at the time when the handover request confirmation message is transmitted is included in the handover request confirmation message together with the re-calculated wrap-around DRX start offset value (wrap_arounded_drxStartOffset). It may be included and delivered to the source base station. The measured absolute time may be used as information for estimating the state transition of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the source base station.

In another embodiment of the present invention, the handover request confirmation message may not include an information element for enhanced DRX operation.

Following step S2325, the source base station transmits a handover command to the terminal (S2330). The handover command may be transmitted through an RRC connection reconfiguration, and an RRC connection reconfiguration message may be transmitted from a source base station to a terminal. The DRX pattern recommended by the source base station is transmitted through the handover command.

According to an embodiment of the present invention, the handover command may include a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted at the handover request (S2320).

According to another embodiment of the present invention, when the source base station receives the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated at the target base station through the handover request confirmation, the handover command is the recomputed wrap-around It may include a DRX configuration configured by applying the specified DRX start offset value (wrap_arounded_drxStartOffset).

24 is an example of a block diagram illustrating a terminal and a base station performing a DRX operation according to the present invention.

Referring to FIG. 24, the terminal 2400 includes a receiver 2405, a triggering unit 2410, a DRX performing unit 2415 or a measuring unit 2420, and a transmitting unit 2425.

The triggering unit 2410 performs IDC assistant information triggering (hereinafter referred to as IDC triggering) based on the IDC triggering condition. That is, it triggers the transmission of IDC assistance information. IDC triggering is performed when a coexistence interference in the device occurs and a performance degradation caused by the interference is severe in the terminal 2400, or when a serious performance degradation is expected to occur soon (for example, within several hundred ms). .

For example, the IDC triggering may be performed based on whether IDC is on-going IDC of the terminal 2400 according to the determination in the terminal 2400. As another example, IDC triggering may be performed according to an implementation inside the terminal 2400 as to whether or not the communication may be experienced by the IDC situation.

The transmitter 2425 transmits IDC assistance information to the source base station 2430. In this case, the IDC assistant information may be transmitted together with the measured measurement result. The IDC support information may include unusable frequency band information for the FDM-based IDC solution or may include TDM pattern information for the TDM-based IDC solution. In particular, it may include DRX related information for the DRX operation according to the present invention. The IDC assistance information may include TDM pattern information. Values related to DRX parameters for performing a DRX operation may be recommended and transmitted through the TDM pattern information. For example, DRX period, DRX activity interval, DRX period start offset values may be transmitted, or DRX period, duration interval timer, and DRX subframe offset values may be transmitted. The unit of the DRX period, the DRX subframe offset, and the DRX start offset value may be a subframe, a duration timer may also be given in subframe units, and the duration timer may be given in units of PDCCH-subframes. In addition, the IDC assistance information may include DRX pattern information or HARQ based reservation bitmap pattern information as information for correct DRX operation for IDC. In this case, the DRX pattern may include a DRX cycle and a scheduled cycle value, and may further include a DRX start offset value. Here, the DRX start offset value may mean a time point at which the duration timer of the DRX cycle operates. The DRX start offset value is determined based on the system frame number (SFN) 0 and the subframe number 0, and may be in a subframe (or system frame) unit. For example, the DRX start offset value may mean a time offset between WLAN and LTE for protection of periodic beacon transmission in the WLAN. In addition, the HARQ based reservation bitmap pattern refers to subframes in which LTE transmission and reception are allowed in consideration of transmission timings of LTE HARQ processes.

The receiver 2405 receives an RRC connection reconfiguration message including an IDC solution selected by the source base station 2430 based on IDC assistance information. In this case, when the measurement result is not received together with the IDC assistant information, a TDM IDC operation may be transmitted to the IDC solution.

The measurement unit 2420 performs the measurement and reports the measurement result to the source base station 2430. In this case, the transmitted measurement report is a measurement result in which the influence of IDC interference is removed. The specific IDC interference effects may be removed according to the implementation of the terminal 2400.

The receiver 2405 receives a handover command from the source base station 2430. The handover command may be transmitted through an RRC connection reconfiguration, and an RRC connection reconfiguration message may be transmitted from the source base station 2430 to the terminal 2400. The DRX pattern recommended by the source base station 2430 is transmitted through the handover command.

According to an embodiment of the present invention, the handover command may include a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted when a handover request is made.

According to another embodiment of the present invention, when the source base station 2430 receives the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated by the target base station 2460 through the handover request confirmation, the handover command may be used. It may include a DRX setting configured by applying the recalculated wrap-around DRX start offset value (wrap_arounded_drxStartOffset).

The DRX execution unit 2415 performs an enhanced DRX operation based on the handover command after being connected to the target base station 2460. The DRX operation may be performed based on the DRX configuration received through the handover command. The DRX operation is not necessarily performed based on the DRX setting recommended by the source base station 2430 through the handover command, but is based on the DRX setting set by the UE 2400 or the DRX setting updated by the UE 2400. DRX operations may be performed.

The DRX execution unit 2415 may perform a DRX operation based on the DRX setting included in the handover command, wherein the DRX setting is a wrap-around DRX calculated based on Equations 3 to 6 It may be a start offset value, and the wrap-around DRX start offset may be a value calculated at the source base station 2430 or a value calculated at the target base station 2460 again.

If it is determined that the wrap-around DRX start offset value received through the DRX setting when receiving the handover command is an offset value that is not suitable for the TDM IDC operation (eg, the DRX operation), the transmitter 2425. Transmits IDC assistance information to the target base station 2460. For example, a wrap-around DRX start offset value may be distorted due to a delay in handover, asynchronous system frames between the source base station 2430 and the target base station 2460, and the wrap-around may occur. DRX start offset value may be inappropriate for TDM IDC operation. For another example, when the DRX start offset value updated by the UE 2400 through wrap-around and the DRX start offset value received through the handover command do not match, the transmitter 2425 may transmit a target base station 2460. ) Can send additional IDC support information. The IDC assistance information may be transmitted through an RRC connection reset (for example, through an RRC connection reset message), in the form of IDC support information used after an RRC connection reset is finished, or random access. It may be included in the RRC connection reset complete message transmitted in the procedure (for example, may be transmitted in the form of an information element of the RRC connection reset message). The target base station 2460 may recalculate a wrap-around DRX start offset value based on Equations 3 to 6 through the IDC assistant information.

If the DRX setting is reconfigured based on this, the DRX execution unit 2415 may perform a DRX operation based on the DRX setting.

The base station may be a source base station 2430 or a target base station 2460.

The source base station 2430 includes a receiver 2435, an IDC resolver 2440, a handover determiner 2445, and a transmitter 2450.

The receiver 2435 receives IDC assistance information from the terminal 2400. In this case, the IDC assistance information may be transmitted together with the measurement result measured by the terminal 2400. The IDC support information may include unusable frequency band information for the FDM-based IDC solution or may include TDM pattern information for the TDM-based IDC solution. In particular, it may include DRX related information for the DRX operation according to the present invention. The IDC assistance information may include TDM pattern information. Values related to DRX parameters for performing a DRX operation may be recommended and transmitted through the TDM pattern information. For example, the DRX period, the DRX activity interval values may be transmitted, or the DRX period, the duration interval timer, the DRX subframe offset value, and the DRX period start offset values may be transmitted. The unit of the DRX period, the DRX period start offset value, and the DRX subframe offset may be a subframe, a duration timer may also be given in subframe units, and the duration timer may be given in PDCCH-subframe units. In addition, the IDC assistance information may include DRX pattern information or HARQ based reservation bitmap pattern information as information for correct DRX operation for IDC. In this case, the DRX pattern may include a DRX cycle and a scheduled cycle value, and may further include a DRX start offset value. Here, the DRX start offset value may mean a time point at which the duration timer of the DRX cycle operates. The DRX start offset value is determined based on the system frame number (SFN) 0 and the subframe number 0, and may be in a subframe (or system frame) unit. For example, the DRX start offset value may mean a time offset between WLAN and LTE for protection of periodic beacon transmission in the WLAN. In addition, the HARQ based reservation bitmap pattern refers to subframes in which LTE transmission and reception are allowed in consideration of transmission timings of LTE HARQ processes.

The IDC resolution unit 2440 selects the most appropriate IDC solution (or IDC control method) based on the IDC support information received from the terminal 2400, and the transmission unit 2450 sends an RRC connection reconfiguration message to the IDC solution. Included in the transmission to the terminal 2400. In this case, when the measurement result is not received together with the IDC assistant information, a TDM IDC operation may be transmitted to the IDC solution.

The receiver 2435 receives a result of the measurement performed by the terminal 2400 from the terminal 2400. In this case, the transmitted measurement report is a measurement result in which the influence of IDC interference is removed. The specific IDC interference effect may be removed according to the implementation of the terminal.

The handover decision unit 2445 performs a handover decision based on the measurement report. For example, a handover may be determined to the target base station 2460 operating in the unusable frequency domain due to the influence of IDC interference.

The transmitter 2450 transmits a handover request to the target base station 2460. In this case, the handover request message may be transmitted from the source base station 2430 to the target base station 2460, and the handover request message may include a TDM pattern. The handover request message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the TDM pattern may include updated DRX start offset information (wrap-around DRX start offset value) in order to seamlessly apply the enhanced DRX operation during the handover procedure according to the present invention. have. It may be a wrap-around DRX start offset value calculated based on Equations 3 to 6.

That is, when the handover request message is transmitted, the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) calculated by the source base station 2430 is included in the handover request message and transmitted to the target base station 2460. Through Equations 3 to 6, the last updated wrap-around DRX start offset value is transmitted through the application of several wrap-arounds.

In another embodiment of the present invention, the absolute time measured by the source base station 2430 at the time when the handover request message is transmitted is included in the handover request message together with the wrap-around DRX start offset value (wrap_arounded_drxStartOffset). May be sent to 2460. The measured absolute time may be used as information for estimating a state variation of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the target base station. For example, the measured absolute time may be in the form of "AM12: 00: 00".

The receiver 2435 receives a handover request confirmation from the target base station 2460 to accept the handover request. In this case, the handover request confirmation message may be transmitted from the target base station 2460 to the source base station 2430. The handover request confirmation message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the handover request confirmation message may include a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated by the target base station 2460 in relation to the enhanced DRX operation. Based on Equations 3 to 6, the DRX start offset value wrap-around at the target base station 2460 may be updated again.

In another embodiment of the present invention, the absolute time measured by the target base station 2460 at the time when the handover request confirmation message is transmitted is the handover request together with the re-calculated wrap-around DRX start offset value (wrap_arounded_drxStartOffset). It may be included in the confirmation message and delivered to the source base station 2430. The measured absolute time may be used as information for estimating the state transition of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the source base station 2430.

In another embodiment of the present invention, the handover request confirmation message may not include an information element for enhanced DRX operation.

The transmitter 2450 transmits a handover command to the terminal 2400. The handover command may be transmitted through an RRC connection reconfiguration, and an RRC connection reconfiguration message may be transmitted from the source base station 2430 to the terminal 2400. The DRX pattern recommended by the source base station 2430 is transmitted through the handover command.

According to an embodiment of the present invention, the handover command may include a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted when a handover request is made.

According to another embodiment of the present invention, when the source base station 2430 receives the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) recalculated by the target base station 2460 through the handover request confirmation, the handover command may be used. It may include a DRX setting configured by applying the recalculated wrap-around DRX start offset value (wrap_arounded_drxStartOffset).

The target base station 2460 includes a receiver 2465, a controller 2470, and a transmitter 2475.

The receiver 2465 receives a handover request from the source base station 2430. In this case, the handover request message may be transmitted from the source base station 2430 to the target base station 2460, and the handover request message may include a TDM pattern. The handover request message may be transmitted through an X2 interface (or S1 interface).

In one embodiment of the present invention, the TDM pattern may include updated DRX start offset information (wrap-around DRX start offset value) in order to seamlessly apply the enhanced DRX operation during the handover procedure according to the present invention. have. It may be a wrap-around DRX start offset value calculated based on Equations 3 to 6.

That is, when the handover request message is transmitted, the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) calculated by the source base station 2430 is included in the handover request message and transmitted to the target base station 2460. Through Equations 3 to 6, the last updated wrap-around DRX start offset value is transmitted through the application of several wrap-arounds.

In another embodiment of the present invention, the absolute time measured by the source base station 2430 at the time when the handover request message is transmitted is included in the handover request message together with the wrap-around DRX start offset value (wrap_arounded_drxStartOffset). May be sent to 2460. The measured absolute time may be used as information for estimating a state variation of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the target base station 2460. For example, the measured absolute time may be in the form of "AM12: 00: 00".

The controller 2470 may determine a time gap between the source base station 2430 and the target base station 2460 based on the measured absolute time. A wrap-around DRX start offset may be adjusted based on the time gap.

The transmitter 2475 transmits a handover request confirmation to the source base station 2430 in order to accept the handover request. In this case, the handover request confirmation message may be transmitted from the target base station 2460 to the source base station 2430. The handover request confirmation message may be transmitted through an X2 interface (or S1 interface).

According to an embodiment of the present invention, the controller 2470 recalculates the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) in relation to the enhanced DRX operation, and the transmitter 2475 responds to the handover request confirmation message. A recalculated wrap-around DRX start offset value may be included and transmitted.

The controller 2470 may update the wrap-around DRX start offset value based on Equations 3 to 6 again.

According to another embodiment of the present invention, the absolute time measured by the controller 2470 at the time when a handover request confirmation message is transmitted is confirmed with the re-calculated wrap-around DRX start offset value (wrap_arounded_drxStartOffset). Included in the message may be delivered to the source base station 2430. The measured absolute time may be used as information for estimating the state transition of the wrap-around DRX start offset value (wrap_arounded_drxStartOffset) at the source base station 2430.

In another embodiment of the present invention, the handover request confirmation message may not include an information element for enhanced DRX operation.

If the UE 2400 determines that the wrap-around DRX start offset value received through the DRX configuration when receiving the handover command is an offset value unsuitable for performing the TDM IDC operation (eg, the DRX operation), The receiver 2465 receives IDC support information from the terminal 2400. For example, a wrap-around DRX start offset value may be distorted due to a delay in handover, asynchronous system frames between the source base station 2430 and the target base station 2460, and the wrap-around may occur. DRX start offset value may be inappropriate for TDM IDC operation. For another example, when the DRX start offset value updated by the UE 2400 through wrap-around and the DRX start offset value received through the handover command do not match, the transmitter 2425 may transmit a target base station 2460. ) Can send additional IDC support information. The IDC assistance information may be transmitted through an RRC connection reset (for example, through an RRC connection reset message), in the form of IDC support information used after an RRC connection reset is finished, or random access. It may be included in the RRC connection reset complete message transmitted in the procedure (for example, may be transmitted in the form of an information element of the RRC connection reset message). The target base station 2460 may recalculate a wrap-around DRX start offset value based on Equations 3 to 6 through the IDC assistant information.

When the DRX setting is reconfigured based on this, the transmitter 2475 may transmit data to the terminal 2400 to allow the terminal 2400 to perform a DRX operation.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (12)

In a terminal for transmitting control information in a wireless communication system,
A triggering unit for triggering transmission of IDC assistance information based on an IDC triggering condition;
A transmitter for transmitting IDC assistance information including information related to TDM-based DRX operation to a source base station;
A receiver configured to receive an RRC connection reconfiguration message including an IDC solution selected by the source base station based on the IDC assistance information; And
A measurement unit for performing the measurement and reporting the measurement result to which the influence of IDC interference has been removed to the source base station,
The receiving unit receives a handover command from the source base station including a DRX setting recommended by the source base station based on the measurement result,
The DRX setting is a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted in a handover request. The method of claim 1,
And a DRX performer configured to perform a DRX operation based on the handover command after being connected to a target base station. 3. The method of claim 2,
The DRX execution unit,
And a DRX operation based on a wrap-around DRX start offset value determined based on a DRX start offset value of a system frame before wrap-around. The method of claim 3, wherein
The wrap-around DRX start offset is a value calculated at the source base station or a value recalculated at the target base station. 5. The method of claim 4,
If it is determined that the wrap-around DRX start offset value received through the DRX setting when receiving the handover command is inappropriate to perform a DRX operation,
The transmitter
And transmitting IDC assistant information to the target base station. The method of claim 5, wherein
The receiver may further comprise:
Receive the wrap-around DRX start offset value recalculated by the target base station through the IDC assistance information,
The DRX execution unit,
And reconfiguring a DRX setting based on the recalculated wrap-around DRX start offset value, and performing a DRX operation based on the reconfigured DRX setting. In a method for transmitting control information by a terminal in a wireless communication system,
Triggering transmission of IDC assistance information based on the IDC triggering condition;
Transmitting IDC assistance information including TDM-based DRX operation related information to a source base station;
Receiving, by a source base station, an RRC connection reconfiguration message including an IDC solution selected based on the IDC assistance information;
Performing the measurement and reporting the measurement result to which the influence of IDC interference has been removed to the source base station; And
Receiving a handover command from the source base station including a DRX setting recommended by the source base station based on the measurement result,
The DRX setting is a DRX setting configured by applying a wrap-around DRX start offset value (wrap_arounded_drxStartOffset) transmitted in a handover request. In the base station for transmitting control information in a wireless communication system,
Receiving unit for receiving the IDC support information or measurement results from the terminal;
An IDC solver that selects the most appropriate IDC solution based on the IDC assistance information;
A transmitter for including the IDC solution in an RRC connection reconfiguration message and transmitting it to the terminal; And
A handover decision unit for performing a handover decision to a target base station based on the measurement result;
The transmitter transmits a handover request to the target base station through an X2 interface or an S1 interface.
The base station comprising a wrap-around DRX start offset value determined based on a DRX start offset value of a system frame before wrap-around; The method of claim 8,
The transmitter
And the absolute time measured by the source base station at the time point when the handover request is transmitted is included in the handover request and transmitted to the target base station. The method of claim 8,
The receiving unit
Receive a handover request confirmation from the target base station to accept the handover request,
The handover request acknowledgment includes a wrap-around DRX start offset value recalculated by the target base station or an absolute time measured by the target base station. The method of claim 8,
The transmitter further transmits a handover command to the terminal.
Wherein the handover command includes a DRX configuration configured by applying a wrap-around DRX start offset value transmitted in the handover request. In a method for transmitting control information from a base station in a wireless communication system,
Receiving IDC assistance information or a measurement result from the terminal;
Selecting the most appropriate IDC solution based on the IDC assistance information;
Including the IDC solution in an RRC connection reconfiguration message and transmitting it to the terminal;
Performing a handover decision to a target base station based on the measurement result; And
Transmitting a handover request to the target base station through an X2 interface or an S1 interface,
The handover request includes a wrap-around DRX start offset value determined based on a DRX start offset value of a system frame before wrap-around.

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