WO2008127038A1

WO2008127038A1 - Device and method for transmitting downlink scheduling control signalling in wireless communication system

Info

Publication number: WO2008127038A1
Application number: PCT/KR2008/002057
Authority: WO
Inventors: Ju-Ho Lee; Xiaoqiang Li; Yingyang Li; Yujian Zhang
Original assignee: Beijing Samsung Telecom R&D Center; Samsung Electronics Co Ltd
Current assignee: Beijing Samsung Telecom R&D Center; Samsung Electronics Co Ltd
Priority date: 2007-04-11
Filing date: 2008-04-11
Publication date: 2008-10-23
Anticipated expiration: 2009-10-11
Also published as: CN101287281A

Abstract

The present invention provides a method for transmitting downlink scheduling control signaling in a TDD system. In a TDD system, BS transmits the time domain resource information in downlink physical control channel to indicate which sub-frames among the residual ones in a scheduling period are used to transmit downlink data; BS transmits the downlink physical control channel. With the method, overhead can be effectively reduced in downlink physical control channel so that system spectrum utilization ratio is greatly improved. Complexity can be effectively reduced for UE in receiving downlink physical control channel so that the stand-by time of UE is increased. System time-frequency resource can be effectively utilized so that system spectrum utilization ratio is improved.

Description

DEVICE AND METHOD FOR TRANSMITTING DOWNLINK SCHEDULING CONTROL SIGNALLING IN WIRELESS COMMUNICATION SYSTEM

BACKGROUND OF THE INVENTION

FIELD OF INVENTION

The present invention relates to a wireless communication system, in particular to device and method for transmitting downlink scheduling control signaling in a wireless communication system.

DESCRIPTION OF PRIOR ART

Now, the 3^rd Generation Mobile Communication System Partnership Project (3 GPP) Standardization Organization has commenced on Long-term Evolution (LTE) to the existing system specification. Among numerous physical layer transmission techniques, both the downlink transmission technique based on OFDM (Orthogonal Frequency Division Multiplexing) and the uplink transmission technique based on SCFDMA (Single Carrier Frequency Division Multiple Access) are hot spot in research. In nature, OFDM is a kind of multi- carrier modulation communication technology. Its basic principle is to divide a high rate data stream into multiple low rate data streams to be transmitted on a group of orthogonal sub-carriers simultaneously. Because of the nature of multi- carrier, the OFDM technique bears superior performance in many aspects. SCFDMA is essentially a kind of single carrier transmission technology with a lower PAPR (Peak to Average Power Ratio). Therefore, the power amplifier of a mobile terminal can operate efficiently to enlarge cell coverage. Meanwhile, with the addition of Cyclic Prefix and frequency domain equilibrium, SCFDMA technique is lower in processing complexity.

Wireless communication systems can be divided in terms of duplex mode into frequency division duplex (FDD) and time division duplex (TDD). In FDD mode, two-way communication in a wireless system is implemented at two frequencies spaced by a distance so that the communication entity can simultaneously perform receiving and transmitting. In TDD mode, two-way communication in a wireless system is implemented at one same frequency so that the communication entity cannot simultaneously perform receiving and transmitting, i.e., the operations of receiving and transmitting are separated in time. Two different types of TDD frame structures exist in LTE, i.e., Generic TDD Frame Structure and Alternative TDD Frame Structure (A-TDD). The generic TDD frame structure is basically the same as the FDD frame structure, while the alternative TDD frame structure has its own special structure. In the following, description on these two types of frame structures will be given respectively.

According to the existing discussion results on LTE, the FDD and the generic TDD frame structure of downlink in an LTE system are illustrated in Figure 1. The radio resource in an LTE system refers to time and frequency resource that can be occupied by system or user equipment(UE), and it can be differentiated from each other by the unit of radio frame (101-103). The time duration of a radio frame is the same as that in a WCDMA system, i.e., 10ms. Each frame is subdivided into several slots (104-107).Currently it is assumed that each radio frame comprises 20 slots, each of which is 0.5ms long; each slot includes multiple OFDM symbols. According to the present assumptions, in an LTE system, the time duration of a valid OFDM symbol is about 66.7μs. There may be two kinds of CP time durations of OFDM symbol, that is, short CP time duration is about 4.8μs, while long CP time duration is about 16.7μs. The long CP slot is used in the case of multi-cell broadcast/multicast and the case that the cell radius is very long. The short CP slot (108) contains 7 OFDMA symbols, while the long CP slot (109) contains 6 OFDM symbols.

According to the present LTE discussion result, Figure 2 illustrates the frame structure of an LTE A-TDD system, a radio frame (201-203) is 10ms long; each frame is equally divided into two half-frames of 5ms(204, 205); and each half-frame includes seven slots (206-212) and three special fields, i.e., downlink pilot time slot (DwPTS) (213), guard period (GP) (214) and uplink pilot time slot (UpPTS) (215). Time slot 0 (206) and DwPTS in each half-frame are fixed for downlink transmission, and time slot 1 (207) and UpPTS in each half-frame are fixed for uplink transmission. Take the sample rate of 30.72MHz as an example, each slot (206-212) includes 20736 samples and has time of 0.625ms; DwPTS includes 2572 samples and has time of 83.7ms; GP includes 1536 samples and has time of 50ms; UpPTS includes 4340 samples and has time of 141.3ms. As the same as a FDD system, the valid OFDM symbol duration is about 66.7μs, and the CP time duration of an OFDM symbol can be in following two cases: short CP time duration is about 7.29μs, and long CP time duration is about 16.67μs. A short CP slot (216) includes 9 OFDM symbols and one time interval (TI) (218), while a long CP slot (217) includes 8 OFDM symbols and one TI (219). It is noted that the two TIs (218, 219) are different in time duration. According to the present discussion result, each slot is one sub- frame.

In the OFDM system, if user data is mapped to consecutive sub-carriers, the transmission mode is called the localized transmission mode. And if user data is mapped to discretely distributed sub-carriers, it is called the distributed transmission mode. Usually, no overlap will be caused to the sub-carriers for all the UEs in the same cell. This resource allocation method is called orthogonal resource allocation in frequency domain. The orthogonal resource allocation method in time domain is that a base station (BS) transmits data with different time slots or OFDM symbols for the UEs in the same cell. By combining the frequency-domain and time-domain resource allocation methods, downlink resource can be allocated to users in the form of 2D grid of time-domain and frequency-domain in the OFDM system.

In a communication system, BS implements resource allocation and controls reception and transmission of each UE by transmitting control signaling at each scheduling moment. In the present application, the control signaling for each UE is called downlink physical control channel. In the present LTE discussion, the downlink physical control channel can bear both downlink scheduling control signaling and uplink scheduling control signaling. Meanwhile, the downlink physical control channel can also transmit acknowledgement information (ACK/NACK) for uplink transmission data.

In the present discussion on A-TDD, Primary Synchronization Channel (hereafter referred to as P-SCH) is transmitted in DwPTS. P-SCH occupies the 72 central sub-carriers of the system bandwidth. For the residual sub-carriers in DwPTS, one of the current proposals is using them to transmit data.

In the present discussion on LTE, system broadcast information can be transmitted via Primary Broadcast Channel (hereafter referred to as P-BCH) and Dynamic Broadcast Channel (hereafter referred to as D-BCH). In addition, Secondary Broadcast Channel (hereafter referred to as S-BCH) may be defined to transmit broadcast information.

SUMMARY OF THE INVENTION

The object of the present invention is to provide device and method for transmitting downlink scheduling control signaling in a TDD system.

According to one aspect of the present invention, a method for transmitting downlink scheduling control signaling in a time division duplex (TDD) system, comprising: a) In the TDD system, transmitting, by a base station, time domain resource information in downlink physical control channel to indicate sub-frames used in downlink data transmission among residual sub-frames in a scheduling period; b) transmitting said downlink physical control channel by the base station.

According to another aspect of the present invention, a method for receiving control signaling by a user equipment(UE) in a time division duplex(TDD) system, comprising steps of: a) detecting downlink physical control channel by the UE in the TDD system; b) reading downlink data by the UE according to the information on sub- frames that are used for transmitting the downlink data among the residual sub- frame in a scheduling period and indicated by time domain resource information transmitted in the downlink physical control channel. According to another aspect of the present invention, a device for transmitting downlink scheduling control signaling by a base station in a time division duplex(TDD) system, the device comprises a transmitting part and further comprises: a scheduler module which determines how to allocate resource blocks to each user equipment(UE) according to CQI reported by the UE and the data service information of the UE; a control signaling generator module which generates one or more downlink physical control channels according to the allocation of the resource blocks, and transmits time domain resource information in each of the downlink physical control channel to indicate sub-frames used for downlink data transmission among the residual sub- frames in a scheduling period; said transmitting means transmits each of the downlink physical control channel into wireless channel.

According to another aspect of the present invention, a device for processing control signaling by a user equipment(UE) in a time division duplex(TDD) system, the device comprises a receiving part and further comprises: a physical channel de-multiplexer which de-multiplexes the received signal to obtain each downlink physical control channel and other physical channels; a control signaling processor which provides the physical channel demultiplexer with information on sub-frames that are used for downlink data transmission among the residual sub-frames in a scheduling period for downlink data transmission and indicated by time domain resource information transmitted in the downlink physical control channel; said receiving means receives RF signals transmitted from a base station, and transmits to the physical channel de-multiplexer after RF reception and AfD conversion.

According to another aspect of the present invention, a method for transmitting downlink scheduling control signaling in a time division duplex(TDD) system, comprising: a) in the TDD system, configuring, by a base station, to use two sub-frames per half-frame to transmit downlink physical control channel; b) transmitting said downlink physical control channel by the base station.

According to another aspect of the present invention, a method for receiving control signaling by a user equipment(UE) in a time division duplex(TDD) system, comprising: a) in the TDD system, when a base station configures to use two sub-frames per half-frame to transmit downlink physical control channel, receiving, by the UE, only downlink scheduling control signaling in one of said two sub-frames and only uplink scheduling control signaling in the other; b) receiving downlink data or transmitting uplink data by the UE according to the received downlink or uplink scheduling control signaling.

According to another aspect of the present invention, a method for receiving control signaling by a user equipment(UE) in a time division duplex(TDD) system, comprising: a) in the TDD system, when a base station configures to use two sub-frames per half-frame to transmit downlink physical control channel, in the sub-frame that does not transmit downlink scheduling control signaling separately, first detecting, by the UE, whether there is transmission of uplink scheduling control signaling, if yes, further detecting whether there is transmission of downlink scheduling signaling, if no uplink scheduling control signaling is transmitted, stopping detecting downlink physical control channel of the current sub- frame; in the sub-frame that do not transmit uplink scheduling control signaling separately, first detecting, by the UE, whether there is transmission of downlink scheduling control signaling, if yes, further detecting whether there is transmission of uplink scheduling signaling, if no downlink scheduling control signaling is transmitted, stopping detecting downlink physical control channel of the current sub-frame; b) receiving downlink data or transmitting uplink data by the UE according to the received downlink or uplink scheduling control signaling. According to another aspect of the present invention, a method for transmitting downlink scheduling control signaling in a time division duplex(TDD) system, comprising: a) in an alternative TDD frame structure, configuring, by a base station, part of time-frequency resource in downlink pilot time slot to transmit downlink physical control channel; b) transmitting said downlink physical control channel in said downlink pilot time slot by the base station.

With the first method proposed in the present invention, overhead can be effectively reduced in the downlink physical control channel so that system spectrum utilization ratio is greatly improved. With the second method proposed in the present invention, complexity can be effectively reduced for UE in receiving downlink physical control channel so that stand-by time of the UE is greatly extended. With the third method proposed in the present invention, system time-frequency resource can be effectively utilized so that system spectrum utilization ratio is greatly improved.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows the frame structures of downlink FDD and generic TDD in a LTE.

Figure 2 shows the frame structure of LTE A-TDD system.

Figure 3 shows an example of the allocation for uplink and downlink in a LTE A-TDD system.

Figure 4 shows an example of the allocation for uplink and downlink in a LTE generic TDD system.

Figure 5 shows a diagram of device for resource scheduling and control signaling transmitting by BS. .

Figure 6 shows a diagram of device for control signaling processing by UE.

Figure 7 is a schematic diagram of embodiment 1.

Figure 8 is an example of hardware block diagram of a transmitter in BS;.

Figure 9 is an example of hardware block diagram of a receiver in UE. Figure 10 is a schematic diagram of embodiment 2. Figure 11 is a schematic diagram of embodiment 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Three types of devices and methods for transmitting downlink scheduling control signaling in a TDD system are proposed in the present invention.

Method 1 : transmitting in downlink physical control channel time domain resource information indicating sub-frames used in data transmission among the residual scheduling period

This method comprises steps of: a) In the TDD system, transmitting, by a base station, time domain resource information in downlink physical control channel to indicate sub-frames used in downlink data transmission among residual sub-frames in a scheduling period; b) transmitting said downlink physical control channel by the base station.

In Step a) of this method, the scheduling period refers to the downlink time interval for which UE is scheduled. In a LTE A-TDD system, a scheduling period can be divided in two forms. One is to use a half-frame as a scheduling period, and the other is to use as start point of a scheduling period the first downlink sub- frame succeeding a uplink-to-downlink conversion point, and to use sub-frame 0 in the next half-frame as finish point of the scheduling period. Let's take Figure 3 as an example to explain the resource allocation for uplink and downlink. In Figure 3, sub-frame 0 (301), DwPTS (302), sub-frame 3 (307), sub-frame 4 (308), sub-frame 5 (309) and sub-frame 6 (310) are used to transmit downlink data, while UpPTS (304), sub-frame 1 (305) and sub-frame 2 (306) are used to transmit uplink data. The scheduling period of the above first form is shown as scheduling period 1 in Figure 3, including sub-frame 0, sub-frame 3, sub-frame 4, sub-frame 5 and sub-frame 6. The scheduling period of the above second form is show as scheduling period 2 in Figure 3, including sub-frame 3, sub-frame 4, sub-frame 5, sub-frame 6, and sub-frame 0 in the next half-frame. It is noticeable that DwPTS is not included in the above description, since DwPTS includes only one OFDM symbol. If it is used to transmit data, it can be considered as extension of sub- frame 0.

In this method, BS transmits the data of a corresponding UE in the sub- frame for the transmission of downlink physical control channel, and at the same time, uses time domain resource information in the downlink physical control channel to indicate sub-frames among the residual sub-frames in a scheduling period that are used in downlink data transmission. The length of the time domain resource information can be fixed (i.e., independent of the position of the sub- frame transmitted via the downlink physical control channel) or variable (i.e., related to the position of the sub-frame transmitted via the downlink physical control channel). The reason why the length of the time domain resource information can be variable is that within the scheduling period, UE's data is not transmitted before the transmission of the sub-frame transmitted over the downlink physical control channel. In this application, it should be noted that time domain resource information of fixed and variable lengths is on the premise of the resource allocation ratio for uplink and downlink.

The time domain resource information can be indicated in two approaches. One approach is to use Bitmap, i.e., to use one bit to indicate whether a sub-frame has any corresponding downlink data transmission. This approach is very flexible and can support the case where the downlink data is transmitted discontinuously within a scheduling period. The other approach is to indicate the number of used sub-frames. With this approach, it is required that downlink data of some UE be transmitted continuously within a scheduling period.

Since the length of the time domain resource information can be fixed or variable, and the indication can be implemented in two approaches of bitmap and number. The following description is made to the possible four combinations specifically. In the following description, suppose N downlink sub-frames exist in one scheduling period, denoted as DL_t,0 ≤ i ≤ N - l . For instance, in the example of resource allocation for uplink and downlink in the LTE A-TDD system in Figure 3, N = 5. Corresponding to scheduling period 1, DL₀ is sub- frame 0, DL_x is sub-frame 3, DL₂ is sub-frame 4, DZ₃ is sub-frame 5, and DL₄ is sub-frame 6. Corresponding to scheduling period 2, DL₀ is sub-frame 3, DL₁ is sub-frame 4, DL₂ is sub-frame 5, DL₃ is sub-frame 6, and DL₄ is sub- frame 0 in the next half-frame. Corresponding to the first scheduling period in the example of resource allocation for uplink and downlink in the LTE generic TDD system in Figure 3, DL₀ is sub-frame 0, DL₁ is sub-frame 1, DZ₂ is sub-frame 2; and corresponding to the second scheduling period in this case, DL₀ is sub- frame 5, DL_x is sub-frame 6, DL₂ is sub-frame 7. And suppose that UE detects the corresponding downlink physical control channel in DL _} ,0 < j ≤ N - 1.

Combination 1 : the length of the time domain resource information is fixed and bitmap is applied in indication. In this way, bitmap is adopted to indicate whether any data of UE corresponding to the downlink physical control channel is transmitted by sub-frames within the scheduling period except the sub-frames that are adopted to transmit the downlink physical control channel. And in this way, N - I bits are used to indicate whether UEs' downlink data is transmitted in DL₁ ,0 < / < N - 1, i ≠ j . For instance, DL₁ = 1 indicates that UE's downlink data is transmitted in DL₁ , and DL₁ = 0 indicates that no downlink data of UE is transmitted in DL₁. Of course, it is also possible to use DL₁ = 1 to indicate that no downlink data of UE is transmitted in DL₁ , and DL₁ = 0 is used to indicate that UE's downlink data is transmitted in DL₁. Note that in this case, information on DL₁ ,0 < / < j can be arbitrarily configured, since the transmission of UE's downlink data starts with DL₁ in the scheduling period.

Combination 2: the length of the time domain resource information is fixed and the number of sub-frames is applied in indication. In this way, the time domain resource information is the number of sub-frames (except those used to transmit the downlink physical control channel within the scheduling period) that

control channel. In this way, |^~log₂ N^~\ (where \x] means to ceiling operation on x ) bits are fixedly used to indicate whether the UE's downlink data is transmitted in DL₁, j < i ≤ N - \ . Suppose the value indicated by time-frequency resource is M . In this way, M = O indicates that no downlink data of the UE is transmitted in DL_nJ < i ≤ N - \ ; M = I indicates that the UE's downlink data is transmitted in DL_J+l ; M = 2 indicates that the UE's downlink data is transmitted in both

DL "7, _^+₁1 and DL '7, _^+2 ; and so on.

Combination 3: the length of the time domain resource information is variable and bitmap is applied in indication. In this way, bitmap of variable length is used to indicate whether any data of UE corresponding to the downlink physical control channel is transmitted in sub-frames within the scheduling period except those used to transmit the downlink physical control channel. In this way, N -j -l bits are used to indicate whether UEs' downlink data is transmitted in DL,,j < i ≤ N - 1 . For instance, DL₁ = X indicates that UE's downlink data is transmitted in DL₁ , and DL₁ = 0 indicates that no downlink data of UE is transmitted in DL₁. Of course, DL₁ = 1 can also be used to indicate that no downlink data of UE is transmitted in DL₁ , and DL₁ = 0 is used to indicate that UE's downlink data is transmitted in DL₁.

Combination 4: the length of the time domain resource information is variable and the number of sub-frames is applied in indication. In this way, the time domain resource information is the number of sub-frames (except those used to transmit the downlink physical control channel within the scheduling period) that are used to transmit data of the UE corresponding to the downlink physical control channel. In this way,

bits are used to indicate whether the

UE's downlink data is transmitted in DL_nJ < i ≤ N - I . Suppose the value indicated by time frequency resource is M . In this way, M = O indicates that no downlink data of the UE is transmitted in DL₁ ,j < i ≤ N - \ ; M = I indicates that UE's downlink data is transmitted in DL_j+l ; M = 2 indicates that UE's downlink data is transmitted in both DL_J+i and DL_j+2 ; and so on. The difference between this combination and combination 2 lies in that in combination 2, fixed bits are applied to indicate time domain resource information, while in this combination, the length of the time domain resource information is determined by the position where the downlink physical control channel is transmitted. Note that this method is not confined to correspondence to one same UE, or to whether the downlink data transmitted in different sub-frames within the same scheduling period is jointly encoded or individually encoded. Meanwhile, this method is not confined to whether these different sub-frames belong to the same HARQ process or different HARQ processes.

In this method, UE operates as follows: a) In a TDD system, UE detects downlink physical control channel. b) UE reads downlink data according to information on sub-frames which are used in downlink data transmission among the residual sub-frames in the scheduling period and are indicated by the time domain resource information transmitted in the downlink physical channel.

In Step a), UE first detects the downlink physical control channel. UE can detect the downlink physical control channels in all or part of downlink sub- frames (which can be configured by the network) within the scheduling period. Through D-BCH (or S-BCH), BS broadcasts the positions of sub-frames necessary to be specifically detected. Therefore, UE which takes this BS as its serving BS (Serving Node B) can detect the downlink physical control channel according to the configuration information. In addition, BS can separately configure the positions of downlink sub-frames to be detected by each UE through high level signaling.

In Step b), if UE detects that BS transmits downlink physical control channel to it in some sub-frame, it reads this downlink physical control channel and obtains the positions of the sub-frames used by the downlink data within the scheduling period according to the time domain resource information. Thus, UE can read corresponding downlink data.

Figure 5 shows the devices for BS in scheduling resources and transmitting control signaling. In this figure, the control signaling generator 502 in BS embodies the present invention. The scheduler module 501 in BS determines how to allocate resources to respective UEs according to CQI reported from UEs and the data service information on UEs. The control signaling generator 502 in BS generates one or more downlink physical control channels according to the status of resource allocation, and transmits the time domain resource information in each of the downlink physical control channels to indicate sub-frames which are used for the transmission of downlink data among the residual sub-frames within the scheduling period. Finally, BS transmits each of the downlink physical control channels in transmitting means 503. The detailed hardware block diagram of the transmitting means in BS is given in embodiments.

Figure 6 shows the devices for UE in processing control signaling. In this figure, the control signaling processor 603 in UE is embodies the present invention. The receiving means 601 receives RF signal sent from BS. After RF receiving and A/D conversion, the received signal is de-multiplexed in the physical channel de-multiplexer 602 to obtain respective downlink physical control channels and other physical channels. In the control signaling processor 603, UE obtains the information on sub-frames, which are used for the transmission of downlink data among the residual sub-frames within the scheduling period and indicated by the time domain resource information transmitted in the downlink physical control channel, and provides the information to the physical channel de-multiplexer 602, so that UE can read corresponding downlink data. The detailed hardware block diagram of receiving means in UE is given in the the following embodiments.

Method 2: BS configures to transmit downlink physical control channel in two sub-frames in each half-frame. This method includes: a) In a TDD system, BS configures to transmit downlink physical control channel in two sub-frames in each half-frame ; b) BS transmits the downlink physical control channel.

In this method, the positions of the two sub-frames can be fixed or configured by the network. If two fixed sub-frames are adopted, one approach is to transmitting the downlink physical control channel in sub-frame 0 and the first sub-frame succeeding an uplink-to-downlink conversion point. Take as an example the LTE A-TDD system illustrated in Figure 3, the downlink physical control channel is transmitted in sub-frame 0 (301) and sub-frame 3 (307). In the case of configuration by the network, BS broadcasts the positions of the two sub- frames in D-BCH (orS-BCH). Therefore, UE taking this BS as its serving Node B can detect the downlink physical control channel according to the configuration information. In addition, BS can separately notify each UE of the positions of the two sub-frames transmitting the downlink physical control channel through high level signaling.

Three configurations can be set for the type of the downlink physical control channel transmitted in the two sub-frames.

Configuration 1: no restrictions are set on the type of the downlink physical control channel transmitted in the two sub-frames, i.e., both the downlink scheduling control signaling and the uplink scheduling control signaling can be transmitted in the two sub-frames. Such manner offers maximum flexibility for BS in its scheduling.

Configuration 2: only downlink scheduling control signaling is transmitted in through one of the two sub-frames, while only uplink scheduling control signaling is transmitted in the other. For instance, given that the transmission of downlink physical control channels is in sub-frame 0 and the first sub-frame succeeding the uplink-to-downlink conversion point, one approach is to transmit uplink scheduling control signaling in sub-frame 0 and downlink scheduling control signaling in the first sub-frame succeeding the uplink-to-downlink conversion point. In this case, UE can perform corresponding detection in specific sub-frames only according to the type of the control signaling to be detected. For instance, in the above example, in sub-frame 0, UE needs to only detect the downlink physical control channel according to the possible format of the uplink scheduling control signaling; while in the first sub-frame succeeding the uplink- to-downlink conversion point, UE can detect downlink physical control channel only according to the possible format of the downlink scheduling control signaling. Configuration 3: downlink scheduling control signaling is not independently transmitted in one of the two sub-frames, and uplink scheduling control signaling is not independently transmitted in the other sub-frame. In this case, if both downlink scheduling control signaling and uplink scheduling control signaling exist in one half-frame for one UE, BS can select one of the two sub-frames to simultaneously transmit the two downlink physical control channels if the timing requirement is met; or, for the reason of timing, the two control signaling could not be transmitted simultaneously in the same sub-frame, BS transmits the downlink control signaling and the uplink control signaling in the two sub-frames, respectively. Here, the timing reason refers to the restriction on timing position that results from such factors as the processing time of BS or UE, and the frame structure of the TDD system. In the case that UE transmits only downlink scheduling control signaling or uplink scheduling control signaling in one half- frame, the transmission should be only performed in some specific sub-frame, and the sub-frame for the independent downlink scheduling control signaling is different from that for the independent uplink scheduling control signaling. For instance, given that both sub-frame 0 and the first sub-frame succeeding the uplink-to-downlink conversion point are used to transmit downlink physical control channel, the downlink scheduling control signaling is not independently transmitted in sub-frame 0, and the uplink scheduling control signaling is not independently transmitted in the first sub-frame succeeding the uplink-to- downlink conversion point. If both downlink scheduling control signaling and uplink scheduling control signaling are transmitted in one half-frame for one UE, BS can select one of the two sub- frames to simultaneously transmit the two downlink physical control channels if the timing requirement is met; if, for the reason of timing, the two types of control signaling could not be transmitted simultaneously in the same sub-frame, BS transmits the downlink control signaling in the first sub-frame succeeding the uplink-to-downlink conversion point and transmits the uplink control signaling in sub-frame 0. If only downlink scheduling control signaling exists in one half-frame for one UE, BS transmits the downlink control signaling in only the first sub-frame succeeding the uplink-to- downlink conversion point; and if only uplink scheduling control signaling exists in one half-frame for one UE, BS transmits the uplink control signaling in sub- frame 0. UE operates as follows. In the sub-frame which does not transmit independently the downlink scheduling control signaling, UE first detects whether any uplink scheduling control signaling is included in the transmission. If yes, UE further detects whether there is any transmission of downlink scheduling signaling; if not, UE stops detecting the downlink physical control channel of the current sub-frame. In the sub-frame which does not transmit independently the uplink scheduling control signaling, UE first detects whether there is any transmission of downlink scheduling control signaling. If yes, UE further detects whether there is any transmission of uplink scheduling signaling; if not, UE stops detecting downlink physical control channel of the current sub-frame.

Note that the downlink scheduling control signaling discussed above does not include the downlink transmitted ACK/NAK. There are two modes of transmission. One is to transmit ACK/NAK invariably in one of the two sub- frames. For example, both sub-frame 0 and the first sub-frame succeeding the uplink-to-downlink conversion point are adopted to transmit downlink physical control channels. ACK/NAK can be always transmitted in sub-frame 0. The other mode is to transmit ACK/NAK in arbitrary one of the two sub-frames. For each UE, however, which sub-frame is used by BS to transmit downlink ACK/NAK can be determined by the timing requirements or be configured by BS.

Method 3: use part of time-frequency resource in the downlink pilot time slot (DwPTS) to transmit downlink physical control channel

This method includes: a) In the alternative TDD frame structure, BS configures to transmit the downlink physical control channel with part of time-frequency resource in the downlink pilot time slot; b) BS transmits the downlink physical control channel in the downlink pilot time slot.

Since only 72 sub-carriers around the central frequency in the pilot in DwPTS are used to transmit P-SCH, some of the sub-carriers in DwPTS are used to transmit downlink physical control channel in the present invention. The transmitted downlink physical control channel includes the downlink scheduling control signaling, the uplink scheduling control signaling, and ACK/NACK information on the uplink transmission data.

BS configures in D-BCH (or S-BCH) that part of time-frequency resource in DwPTS is used to transmit downlink physical control channel. For instance, BS can configure all sub-carriers in DwPTS, except for the transmission of P-SCH, to transmit one or more of the three types of signaling, i.e., downlink scheduling control signaling, the uplink scheduling control signaling and the ACK/NACK to uplink data.

When UE learns about that transmission of downlink scheduling control signaling and uplink scheduling control signaling in DwPTS, it is necessary for UE to detect not only the downlink scheduling control signaling in downlink sub- frames, but also those in DwPTS. In the case that only ACK/NAK is transmitted in DwPTS, UE detects the transmission in DwPTS only when UE is configured by BS to receive ACK/NAK in DwPTS.

Embodiments

This section gives three embodiments of the present invention. To avoid the description to be redundant, detailed description of well-known functions or means is omitted.

The First Embodiment

This embodiment corresponds to the case that BS transmits the time domain resource information in the downlink physical control channel to indicate the sub- frames which are used to transmit data among the residual sub-frames within a scheduling period.

As shown in Figure 7, sub-frame 0 (701), DwPTS (702), sub-frame 3 (708), sub-frame 4 (709), sub-frame 5 (310) and sub-frame 6 (711) are adopted to transmit downlink data, and UpPTS (704), sub-frame 1 (705), sub-frame 2 (706) are adopted to transmit uplink data. According to the description above, the second type of scheduling period includes sub-frame 3, sub-frame 4, sub-frame 5, sub-frame 6 and sub-frame 0 (712) in the next half- frame. BS operates as follows. In this embodiment, suppose sub-frame 3 (707) is adopted by BS to transmit downlink physical control channel to some UE. The downlink physical control channel locates at the first several OFDM symbols in sub-frame 3. Given that BS adopts sub-frame 3, sub-frame 4 and sub-frame 5 to transmit downlink data to the UE. The above Combination 3 is adopted to transmit the time domain resource information, i.e., bitmap of variable length is used to indicate the time frequency resource information. Then in this embodiment, BS transmits 4-bit time frequency resource information to indicate whether data for the UE is transmitted in sub-frame 4, sub-frame 5, sub-frame 6 and sub-frame 0 in the next half-frame. In this embodiment, BS transmits "1100" to indicate that downlink data for the UE is transmitted in sub-frame 4 and sub- frame 5, and no data is transmitted in sub-frame 6 or sub-frame 0 in the next half- frame.

UE operates as follows. UE first detects the downlink physical control channel. In this embodiment, UE detects that BS has transmitted downlink physical control channel to it in sub-frame 3. UE reads the downlink physical control channel. Through the time domain resource information "1100", UE learns that BS has transmitted the UE's downlink data in sub-frame 4 and sub- frame 5. Therefore, UE knows that within this scheduling period, BS has transmitted downlink data to the UE in sub-frame 3, sub-frame 4 and sub-frame 5, so that UE can read corresponding downlink data.

Figure 8 shows the hardware block diagram of a transmitter in BS. As shown in this figure, BS generates one or more downlink physical control channels (801), and transmits time domain resource information in these channels to indicate the sub-frames which are adopted to transmit downlink data among the residual sub-frames in a scheduling period. Then, such operations as channel coding and interleaving (802) and rate matching (803) are performed to the signal, followed by QAM modulation (804), and the signal is input into multiplexer (809). For data (805) of current UE, BS performs channel coding and interleaving (806), rate matching (807) and QAM modulation (808), and then it inputs the processed signal into the multiplexer (809); the multiplexer (809) multiplexes the control information together with data. Then BS performs such operations as OFDM modulation (IFFT) (810), adding cyclic prefix (811), D/A conversion (812) to the multiplexed signal, and finally the signal is transmitted through the transmitter (813) and antenna (814).

Figure 9 shows an example of the hardware block diagram of UE receiver. UE receives signal from BS through antenna (901) and RF receiver (902). After A/D conversion (903), removal of cyclic prefix (904) and OFDM demodulation (FFT) (905), the received signal is input into de-multiplexer (906). UE first processes the downlink physical control channel output from the de-multiplexer (906), performs such operations as QAM demodulation (907), rate de-matching (908), de-interleaving and channel decoding (909) to obtain the positions of the sub-frames (which are adopted to transmit downlink data within the scheduling period) indicated by the time domain resource information in the decoded downlink physical control channel (910), so that UE can read data from corresponding time-frequency resource in the de-multiplexer (906), and then performs such operations as QAM demodulation (911), rate de-matching (912), de-interleaving and channel decoding (913) to obtain user data (914) finally.

The Second Embodiment

This embodiment corresponds to the case that BS transmits downlink physical control channel in two sub-frames in each half-frame, and further it transmits downlink scheduling control signaling not independently in one of the two sub-frames, and transmits uplink scheduling control signaling not independently in the other. Among all the following three examples, sub-frame 0, sub-frame 3, sub-frame 4, sub-frame 5 and sub-frame 6 are the downlink sub- frames, and sub-frame 1 and sub-frame 2 are the uplink sub-frames. In addition, BS uses sub-frame 0 and sub-frame 3 to transmit downlink physical control channel, and to transmit downlink scheduling control signaling not independently in sub-frame 0, to transmit uplink scheduling control signaling not independently in sub-frame 3. In example 1, BS adopts sub-frame 0 (1002) to transmit downlink physical control channel which contains some UE's uplink scheduling control signaling (1001), and the uplink scheduling control signaling indicates that UE transmits uplink data in sub-frame 2 (1004). UE first detects whether any uplink scheduling control signaling is transmitted in sub-frame 0. In this example, UE has detected the uplink scheduling controls signaling (1001) transmitted from BS, and further it goes on detecting whether there is any transmission of downlink scheduling control signaling and does not detect any corresponding downlink scheduling control signaling. Then, UE transmits uplink data in sub-frame 2.

In example 2, BS adopts sub-frame 3 (1014) to transmit downlink physical control channel which contains some UE's downlink scheduling control signaling (1013), and the downlink scheduling control signaling indicates that UE will receive downlink data in sub-frame 4 (1015) and sub-frame 5 (1016). UE first detects whether any downlink scheduling control signaling is transmitted in sub- frame 3. In this example, UE has detected the downlink scheduling controls signaling (1013) transmitted from BS, and further it goes on detecting whether there is any transmission of uplink scheduling control signaling and does not detect any corresponding uplink scheduling control signaling. Then, UE receives downlink data in sub-frame 4 and sub-frame 5.

In example 3, BS adopts sub-frame 0 (1021) to transmit downlink physical control channel which contains both uplink scheduling control signaling and downlink scheduling control signaling (1020) for some UE. The uplink scheduling control signaling indicates that UE will adopt sub-frame 2 (1023) to transmit uplink data; the downlink scheduling control signaling indicates that UE adopts sub-frame 3 (1024) and sub-frame 4 (1025) to receive downlink data. UE first detects whether any uplink scheduling control signaling is transmitted in sub- frame 0. In this example, UE has detected the uplink scheduling controls signaling transmitted from BS, and further it goes on detecting whether there is any transmission of downlink scheduling control signaling and has detected corresponding downlink scheduling control signaling. Then, UE transmits uplink data in sub-frame 2 and receives downlink data in sub-frame 3 and sub-frame 4. The Third Embodiment:

This embodiment corresponds to the case that BS transmits downlink physical control channel with part of time- frequency resources in DwPTS. In this embodiment, what is transmitted is downlink ACK/NAK.

As shown in Figure 11, BS configures that UE will detect ACK/NAK in DwPTS. Therefore, when UE transmits uplink data in sub-frame 2 (1101), it detects the transmitted ACK/NAK in DwPTS (1102). Note that the downlink ACK/NAK in Figure 11 refers to only ACK/NAK for the UE. Then, based on the information in ACK/NAK, UE determines whether it is necessary to retransmit data.

Claims

WHAT IS CLAIMED IS:

1. A method for transmitting downlink scheduling control signaling in a time division duplex (TDD) system, comprising: a) In the TDD system, transmitting, by a base station, time domain resource information in downlink physical control channel to indicate sub-frames used in downlink data transmission among residual sub-frames in a scheduling period; b) transmitting said downlink physical control channel by the base station.

2. The method according to Claim 1, wherein said scheduling period is a half-frame in a LTE A-TDD system.

3. The method according to Claim 1, wherein in a LTE A-TDD system, said scheduling period uses the first downlink sub-frame succeeding an uplink-to- downlink conversion point as start point, and sub-frame 0 of next half-frame as finish point.

4. The method according to Claim 1, wherein in a LTE generic TDD system, said scheduling period is consecutive downlink transmission interval in a radio frame.

5. The method according to Claim 1, wherein the base station transmits data of a corresponding user equipment(UE) in the sub-frame transmitting the downlink physical control channel.

6. The method according to Claim 1, wherein said time-frequency resource is transmitted in such manner that a bitmap is used to indicate whether the sub- frames within the scheduling period, excluding the sub-frame transmitting the downlink physical control channel, transmits data of UE corresponding to the downlink physical control channel.

7. The method according to Claim 6, wherein, given that one scheduling period contains N downlink sub-frames denoted as DL,,0 ≤ i ≤ N - 1 , and the

UE detects a corresponding downlink physical control channel in DL_j,0 ≤ j ≤ N - l , the time domain resource information uses N - \ bits to indicate whether the downlink data of the UE is further transmitted in DL,,0 ≤ i ≤ N - l,i ≠ j .

8. The method according to Claim 7, wherein DL₁ = 1 indicates that the downlink data of the UE is transmitted in DL₁ , and DL₁ = 0 indicates that no downlink data of the UE is transmitted in DL, .

9. The method according to Claim 7, wherein DZ₁ = 1 indicates that no down illiinnkk ddaattaa ooff tthhee UUEE iiss ttrraannssmmiitttteedd iinn DDlL₁ , and DL₁ = 0 indicates that the downlink data of the UE is transmitted in DL..

10. The method according to Claim 1, wherein said time-frequency resource is transmitted in such manner that information of fixed length is used to indicate the number of the sub-frames within the scheduling period that transmit data of the UE corresponding to the said downlink physical control channel, excluding the sub-frame transmitting the downlink physical control channel.

11. The method according to Claim 10, wherein given that one scheduling period contains N downlink sub-frames denoted as DL_t,0 ≤ i ≤ N - 1 , and the

UE detects a corresponding downlink physical control channel in DL_j,0 ≤ j ≤ N - l , the time domain resource information uses [log₂ JV] bits to indicate whether the downlink data of the UE is further transmitted in DL,,j < i ≤ N - \ .

12. The method according to Claim 11, wherein, given that the value indicated by the time-frequency resource is M , M = O indicates that no downlink data of the UE is in DL₁, j < i ≤ N - 1 ; M = X indicates that the downlink data of the UE is in DL_J+l ; M = 2 indicates that the downlink data of the UE is in both DL_J+i and DL_J+2 ; and so on.

13. The method according to Claim 1, wherein said time-frequency resource is transmitted in such manner that a bitmap of variable length is used to indicate whether the sub-frames within the scheduling period, excluding the sub-frame transmitting the downlink physical control channel, transmits data of UE corresponding to the downlink physical control channel.

14. The method according to Claim 13, wherein, given that one scheduling period contains N downlink sub-frames denoted as DL^O≤i≤N -1, and the

UE detects a corresponding downlink physical control channel in DL_jfi≤j ≤N -1, the time domain resource information uses N-j-l bits to indicate whether the downlink data of the UE is further transmitted in DL,,j<i≤N-l.

15. The method according to Claim 14, wherein DL₁ = 1 indicates that the downlink data of the UE is transmitted in DL₁ , and DL₁ = 0 indicates that no downlink data of the UE is transmitted in DL₁.

16. The method according to Claim 15, wherein DL₁ =1 indicates that no downlink data of the UE is transmitted in DL₁ , and DI₁ = 0 indicates that the downlink data of the UE is transmitted in DL₁.

17. The method according to Claim 1, wherein said time- frequency resource is transmitted in such manner that information of variable length is used to indicate the number of the sub-frames within the scheduling period that succeed the sub-frame transmitting the downlink physical control channel and transmit data of the UE corresponding to the said downlink physical control channel.

18. The method according to Claim 17, wherein given that one scheduling period contains N downlink sub-frames denoted as DL^O≤i≤N-l, and the

UE detects a corresponding downlink physical control channel in DL_j ,0 ≤j≤N-l, the time domain resource information uses |^~log₂(JV - j)^~] bits to indicate whether the downlink data of the UE is further transmitted in DL₍,j<i≤N-\.

19. The method according to Claim 18, wherein, given that the value indicated by the time-frequency resource is M , M = O indicates that no downlink data of the UE is in DL_n j <i≤N -1; M = X indicates that the downlink data of the UE is in DL_J+λ ; M = 2 indicates that the downlink data of the UE is in both DZ₇₊₁ and DL_J+2 ; and so on.

20. A method for receiving control signaling by a user equipment(UE) in a time division duplex(TDD) system, comprising steps of: a) detecting downlink physical control channel by the UE in the TDD system; b) reading downlink data by the UE according to the information on sub- frames that are used for transmitting the downlink data among the residual sub- frame in a scheduling period and indicated by time domain resource information transmitted in the downlink physical control channel.

21. A device for transmitting downlink scheduling control signaling by a base station in a time division duplex(TDD) system, the device comprises a transmitting part and further comprises: a scheduler module which determines how to allocate resource blocks to each user equipment(UE) according to CQI reported by the UE and the data service information of the UE; a control signaling generator module which generates one or more downlink physical control channels according to the allocation of the resource blocks, and transmits time domain resource information in each of the downlink physical control channel to indicate sub-frames used for downlink data transmission among the residual sub-frames in a scheduling period; said transmitting means transmits each of the downlink physical control channel into wireless channel.

22. A device for processing control signaling by a user equipment(UE) in a time division duplex(TDD) system, the device comprises a receiving part and further comprises: a physical channel de-multiplexer which de-multiplexes the received signal to obtain each downlink physical control channel and other physical channels; a control signaling processor which provides the physical channel demultiplexer with information on sub-frames that are used for downlink data transmission among the residual sub-frames in a scheduling period for downlink data transmission and indicated by time domain resource information transmitted in the downlink physical control channel; said receiving means receives RF signals transmitted from a base station, and transmits to the physical channel de-multiplexer after RF reception and A/D conversion.

23. A method for transmitting downlink scheduling control signaling in a time division duplex(TDD) system, comprising: a) in the TDD system, configuring, by a base station, to use two sub-frames per half-frame to transmit downlink physical control channel; b) transmitting said downlink physical control channel by the base station.

24. The method according to Claim 23, wherein the positions of said two sub-frames are fixed.

25. The method according to Claim 24, wherein said two sub-frames are sub-frame 0 and the first sub-frame succeeding an uplink-to-downlink conversion point, respectively.

26. The method according to Claim 23, wherein the positions of said two sub-frames are configured by network.

27. The method according to Claim 26, wherein the base station broadcasts the positions of said two sub-frames in D-BCH (or S-BCH).

28. The method according to Claim 26, wherein the base station separately informs each user equipment(UE) of the positions of said two sub-frames through high level signaling.

29. The method according to Claim 23, wherein each of said two sub-frames can transmit both downlink scheduling control signaling and uplink scheduling control signaling.

30. The method according to Claim 23, wherein one of said two sub-frames transmits only downlink scheduling control signaling, and the other transmits only uplink scheduling control signaling.

31. The method according to Claim 30, wherein when said two sub-frames are sub-frame 0 and the first sub-frame succeeding a uplink-to-downlink conversion point, respectively, sub-frame 0 transmits uplink scheduling control signaling, and the first sub-frame succeeding a uplink-to-downlink conversion point transmits downlink scheduling control signaling.

32. The method according to Claim 23, wherein one of said two sub-frames does not transmit downlink scheduling control signaling separately, and the other does not transmit uplink scheduling control signaling separately.

33. The method according to Claim 32, wherein when said two sub-frames are sub-frame 0 and the first sub-frame succeeding a uplink-to-downlink conversion point, respectively, sub-frame 0 does not transmit downlink scheduling control signaling separately, and the first sub-frame succeeding a uplink-to-downlink conversion point does not transmit uplink scheduling control signaling separately.

34. The method according to Claim 23, wherein ACK/NAK is always transmitted in the same one of said two sub-frames.

35. The method according to Claim 34, wherein ACK/NAK is always transmitted in sub-frame 0.

36. A method for receiving control signaling by a user equipment(UE) in a time division duplex(TDD) system, comprising: a) in the TDD system, when a base station configures to use two sub-frames per half-frame to transmit downlink physical control channel, receiving, by the UE, only downlink scheduling control signaling in one of said two sub-frames and only uplink scheduling control signaling in the other; b) receiving downlink data or transmitting uplink data by the UE according to the received downlink or uplink scheduling control signaling.

37. A method for receiving control signaling by a user equipment(UE) in a time division duplex(TDD) system, comprising: a) in the TDD system, when a base station configures to use two sub-frames per half-frame to transmit downlink physical control channel, in the sub-frame that does not transmit downlink scheduling control signaling separately, first detecting, by the UE, whether there is transmission of uplink scheduling control signaling, if yes, further detecting whether there is transmission of downlink scheduling signaling, if no uplink scheduling control signaling is transmitted, stopping detecting downlink physical control channel of the current sub-frame; in the sub-frame that do not transmit uplink scheduling control signaling separately, first detecting, by the UE, whether there is transmission of downlink scheduling control signaling, if yes, further detecting whether there is transmission of uplink scheduling signaling, if no downlink scheduling control signaling is transmitted, stopping detecting downlink physical control channel of the current sub-frame; b) receiving downlink data or transmitting uplink data by the UE according to the received downlink or uplink scheduling control signaling.

38. A method for transmitting downlink scheduling control signaling in a time division duplex(TDD) system, comprising: a) in an alternative TDD frame structure, configuring, by a base station, part of time-frequency resource in downlink pilot time slot to transmit downlink physical control channel; b) transmitting said downlink physical control channel in said downlink pilot time slot by the base station.

39. The method according to Claim 38, wherein said downlink physical control channel is downlink scheduling control signaling.

40. The method according to Claim 38, wherein said downlink physical control channel is uplink scheduling control signaling.

41. The method according to Claim 38, wherein said downlink physical control channel is acknowledgement information (ACK/NACK) for uplink transmission data.

42. The method according to Claim 38, wherein in D-BCH (or S-BCH), the base station configures part of time-frequency resource in DwPTS to transmit the downlink physical control channel.