KR101659692B1 - Method for System Interference-Aware Uplink Power Control in 3GPP LTE-A HetNet - Google Patents

Abstract

An uplink power control method and system based on interference recognition in a 3GPP LTE-A heterogeneous network environment is presented. A method of controlling uplink power based on interference recognition according to an embodiment of the present invention includes a step of initializing parameters of a closed loop power control (CL-PC) connected to a network by users, allocating a PRB to the users, Measuring an interference (IoT) due to a terminal for loop power control and open loop-power control, determining parameters of the open loop-power control, determining a transmit power set using parameters of the open loop- Determining a parameter of the transmit power control command using the transmit power control command value, reporting the power headroom according to the determined transmit power control command parameter, And the modulation and coding scheme based on the selected level of modulation using the reported power headroom. And calculating a dependency parameter of the technique.

Description

TECHNICAL FIELD [0001] The present invention relates to a 3GPP LTE-A heterogeneous network environment,

The present invention relates to an interference-aware uplink power control method and system for improving cell capacity in a 3GPP LTE-A HetNet environment.

In the 3GPP LTE-A uplink, orthogonality is provided by eliminating intra-cell interference by single carrier-frequency division multiple access (SC-FDMA).

The 3GPP LTE-A is designed to use an aggressive frequency reuse scheme for both the downlink and the uplink, which allows all cells in the network to use the same frequency band (frequency) to maximize spectral efficiency. band.

1 is a diagram illustrating a 3GPP LTE-A HetNet interference scenario according to an embodiment of the present invention.

Low-power, short-range, and low-cost base stations, called femto eNBs, in 3GPP LTE-A Heterogeneous Network (HetNet) Are installed by consumers with the cost-effective solutions to meet the increasing demand for traffic data.

In order to handle inter-cell interference in the uplink, it is necessary to minimize interference to other cells in the network, maximize the battery life of the mobile terminal, and provide appropriate transmission power of the signals required to achieve the required quality Fractional power control (FPC) is proposed for setting the power consumption.

[0003] As evolving from UMTS RAN (Universal Mobile Telecommunications System Radio Access Network) to LTE, most of the Radio Network Controller (RNC) functions are moved to eNBs, or LTE Base Stations (BSs) (Peer-to-peer) method over other eNBs.

The user (UE) transmission power in the 3GPP LTE-A FPC is determined as follows:

Where P _tx is the UE transmit power at the subframe I, P _max is the maximum allowable user transmit power at 23 dBm, M is the number of physical resource blocks (PRBs) allowed to the user And as more PRBs are allowed to the user, more UE transmission power is required. And, P ₀ is the target received power (target received power), α is a path loss compensation factor (pathloss compensation factor), PL is a path loss between the user and the user's serving base station (serving base station) (pathloss) , Δ MCS = Modulation and coding scheme (MCS) dependent parameter, f (i) represents a transmit power control (TPC) command.

A major challenge in the HetNet environment is the unplanned femtocell deployments according to the aggressive frequency reuse scheme, which is a significant inter-cell uplink in the network causing capacity degradation. Causing interference. We propose a power and spectral efficient uplink power control scheme to provide capacity improvement under networks with high uplink interference because these unplanned small cells make the network more dense and inter-cell interference problems become more serious .

In one aspect, the interference-based uplink power control method proposed by the present invention includes a step of initializing a closed loop-power control (CL-PC) parameter to which users are connected to a network and allocating a PRB Measuring an interference (IoT) due to the terminal for the closed-loop power control and open loop-power control, determining parameters of the open loop-power control, determining parameters of the open loop- Determining a parameter of a transmission power control command using the transmission power control command value, determining a parameter of the transmission power control command based on the determined transmission power control command parameter, Based on the modulation and coding technique level selection using the reported power headroom And calculating a dependent parameter of the modulation and coding scheme.

Wherein determining the parameters of the open loop-power control comprises: setting an initial parameter of the open loop-power control; determining an overload indicator received when the interference (IoT) through the terminal is higher than a predetermined threshold Determining whether the update period of the _{P0_CELL} value is a predetermined value if the update period of the _{P0_CELL} value is a predetermined value, determining whether the update period of the _{P0_CELL} value is a predetermined value, With the number of the received overload indices, and updating the P 0 - _CELL value according to the comparison result.

The step of updating the _{P0_CELL} value according to the comparison result decreases the cell performance value by the target received power when the upper limit number is smaller than the number of the received overload indices.

And updating the P 0 - _CELL value according to the comparison result, if the upper limit number is larger than the number of the received overload indices and the lower limit number is greater than the received overload indices, By the target received power.

Wherein determining the parameters of the open loop-power control comprises: setting an initial parameter of the open loop-power control, averaging the interference (IoT) due to the terminal, updating the update period of the _{P0_UE} value to a predetermined value is correct, if the step of determining, an update cycle of said P _{0_UE} value predetermined appropriate value, when calculating the P _{0_UE} value, an update cycle of said P _{0_UE} value is a predetermined value fit, interference with the terminal (IoT) with a predetermined threshold value.

_{Comparing the} interference (IoT) through the terminal with a predetermined threshold value when the update period of the _{P0_UE} value meets a predetermined value, comparing the interference (IoT) through the terminal with the predetermined threshold Transmitting the overload indicator to the interference cell; and not transmitting the overload indicator to the interference cell when the interference due to the terminal (IoT) is less than the predefined threshold.

Wherein determining the parameter of the transmit power control command using the transmit power control command value comprises: averaging the received SINR; confirming that the period of the transmit power control command has been updated; Calculating a difference between the SINRs, and determining the transmit power control command value according to a difference between the target SINR and the averaged received SINR.

Wherein calculating the dependent parameter of the modulation and coding scheme based on modulation and coding technique level selection using the reported power headroom includes averaging the received SINR, determining whether the dependent parameter of the modulation and coding scheme has been updated Determining an interference channel quality indication if the dependent parameter of the modulation and coding scheme has been updated; determining whether the reported power headroom is present; if the reported power headroom is present, Updating the interference channel quality indication according to the power headroom, and calculating dependent parameters of the modulation and coding technique based on the interference channel quality indication.

In another aspect, the interference-aware uplink power control system proposed by the present invention includes an initialization unit connected to a network and initializing a closed loop-power control (CL-PC) parameter, An interference measurement unit for measuring the interference (IoT) through the terminal for the closed-loop power control and the open loop-power control, an interference measurement unit for determining the parameters of the open- A parameter determination unit for determining a parameter of a transmission power control command using a value of a transmission power control command having a transmission power set using a parameter of the open loop power control, A transmitter for reporting an electric power headroom according to the received power headroom, And a calculation unit for calculating dependent parameters of the modulation and coding scheme based on the technique level selection.

Wherein the parameter determiner sets an initial parameter of the open loop power control and determines whether an overload indicator received when the interference (IoT) through the terminal is higher than a predetermined threshold is received, If the received, wherein when the update frequency of the P _{0_CELL} value predetermined correct value is determined, and the value wherein the update period of the P _{0_CELL} value predetermined, comparing the upper limit number, and the lower the number the number of the received overload indicator And updates the P 0 - _CELL value according to the comparison result.

The parameter determination section the open-loop update of the P ₀ value is determined to set the initial parameters of the power control, and to average the interference (IoT) through the terminal an update cycle of said P ₀ value meets a predetermined value, If the period is a predetermined value suitable to calculate the values P _0, and comparing the predetermined threshold and the interference (IoT) caused by the terminal.

Wherein the calculation unit averages the received SINR and determines whether the dependent parameter of the modulation and coding scheme has been updated to determine an interference channel quality indication when the dependent parameter of the modulation and coding scheme has been updated, And if there is the reported power headroom, updating the interference channel quality indication according to the reported power headroom and calculating a dependent parameter of the modulation and coding scheme based on the interference channel quality indication .

According to embodiments of the present invention, the user performance _{P0_UE} increases the transmission power of the intra-cell user while suppressing the transmission power of the users causing high interference to neighbor cells, and improves the user average performance of the cell edge users Lt; / RTI > can be reduced. The cell edge performance reduction can be minimized by maintaining the interference level at the threshold value due to the P 0 - _CELL value control based on the overload index. In addition, by using CL-PC, the fading effect is compensated to allow the uplink SINR to meet the target SINR determined by the OL-PC.

1 is a diagram illustrating a 3GPP LTE-A HetNet interference scenario according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an uplink power control method based on interference recognition according to an embodiment of the present invention. Referring to FIG.
FIG. 3 is a flowchart illustrating a process of determining parameters of an open loop-power control according to an embodiment of the present invention.
4 is a flowchart illustrating a process of determining a dependent parameter of a modulation and coding scheme according to an embodiment of the present invention.
5 is a flowchart illustrating a process of determining transmission power control command parameters according to an embodiment of the present invention.
6 is a diagram illustrating a configuration of an uplink power control system based on an interference recognition according to an embodiment of the present invention.

In the present invention, an interference-aware uplink power control scheme is proposed to improve cell capacity in a 3GPP LTE-A HetNet environment.

The proposed method uses incoming and outgoing interference to take HetNet's complex interference situation while setting open-loop power control (OL-PC) parameters.

Open-loop power control (OL-PC) parameters are obtained by compensating a channel change caused by a fading effect by applying closed-loop power control (CL-PC) Open-loop power control (OL-PC) receives an SINR to meet the target SINR set by the BS.

Open-loop power control (OL-PC) controls the power spectral density (PSD), which is the power allocated to each PRB, as follows.

The target received power may be calculated as the sum of cell-specific value and UE-specific value P 0 - _CELL and P ₀ - UE, respectively, as follows.

P ₀ is broadcasted to the user using system information block 2 (SIB 2). For example, the broadcasting period is {8, 16, 32, 64, 128, 256 , 512} radio frames. At this time, eight radio frames (80 ms) are selected as the SIB2 broadcasting period in order to change P ₀ dynamically.

Then, an uplink transmit power is set based on a downlink path loss estimate to compensate for the uplink path loss PL.

a is selected from a range of {0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}, wherein the values of 0 and 1 are no compensation and no compensation , While others are partial pathloss compensation factors in the FPC technique.

Closed-loop power control (CL-PC) is supported in the CL-PC, and the base station supports the user to control the power.

[Delta] _MCS is a value determined by the transport format selected by the base station for uplink transmission and is calculated as follows.

는 다른 MCS 레벨에 상응하여 제공된다. Where Bit Per Resource Element (BPRE) is calculated as O _CQI / N _RE , O _CQI is the number of CQI bits, and N _RE is the number of resource elements (REs). K _s is given by the parameter deltaMCS-Enabled provided as a higher layer of 1.25. And,

Are provided corresponding to different MCS levels.

f (i) is a transmit power control (TPC) command sent by the base station to the user to increase or decrease the transmit power based on a comparison of the received SINR and target SINR.

Where i represents the i < th > subframe, and the above equation represents four subframe delays from subframe i. δ _PUSCH is the TPC command value, which is defined as shown in Table 1.

<Table 1>

Then, the user reports a parameter called power headroom (PH), which is calculated as follows.

Therefore, the user can report to the base station how much transmission power is required in the previous subframe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a flowchart illustrating an uplink power control method based on interference recognition according to an embodiment of the present invention. Referring to FIG.

The proposed interference-aware uplink power control method includes a step 210 of users connected to a network and initializing a closed loop-power control (CL-PC) parameter, a step 220 of allocating a PRB to the users, Measuring (230) interference (IoT) through the terminal for the closed-loop power control and open loop-power control, determining (240) the parameters of the open loop-power control, (250) a transmission power control command value having a set transmission power using a parameter of the control, determining (260) a parameter of a transmission power control command using the transmission power control command value, (270) reporting power headroom in accordance with the parameters of the power control command, using the reported power headroom to determine the modulation and coding technique based on the modulation and coding technique level selection And a step 280 of calculating the dependent parameters of the tank and a coding scheme.

In step 210, the users UEs are connected to the network and the closed loop-power control (CL-PC) parameter can be initialized to zero. In other words, the RRC (Radio Resource Control) connection, the modulation and coding scheme dependent parameter? _MCS , and the transmission power control command parameter f (i) are initialized.

In step 220, a PRB may be assigned to the users. And allocates PRB = M to the user by using resource allocation schemes of 3GPP LTE-A.

In step 230, the interference (IoT) through the terminal is measured for the closed-loop power control and open loop-power control. (F) Measures the interference occurring in the eNB. The base station (BS) i measures the interference over thermal (IoT) through the terminal as follows.

IoT _{BS, i} is the interference through the terminal is the uplink interference level in the total band allocated to the base station (BS) i. Thereafter, IoT _{BS, i} is allocated using a higher layer filter.

Then, the base station compares the averaged IoT _{BS, i} with the threshold IoT expressed by IoT _TH . If IoT _{BS, i} is higher than IoT _TH , an overload indicator (OI) message is reported to neighboring cells, otherwise report.

In step 240, parameters of the open loop-power control are determined. The step of determining the parameters of the open loop-power control will be described in more detail with reference to Fig.

FIG. 3 is a flowchart illustrating a process of determining parameters of an open loop-power control according to an embodiment of the present invention.

3A is a flowchart illustrating a process of determining a _PoCELL value based on an outflow interference according to an embodiment of the present invention.

In step 310a, an initial parameter of open loop-power control is set. At this time, it sets the initial value of P _{O_CELL} _m, P _{O_CELL} _f, ΔP _0, N _D, N _U. At step 320a, N = 0 is initialized.

At step 330a, it is determined if the received overload indicator is received if the interference (IoT) through the terminal is higher than a predetermined threshold.

If the overload indicator has been received, then in step 340a, update to N = N + 1 and then to step 350a. If the overload indicator has not been received, the flow directly goes to step 350a.

In step 350a, it is determined based on the outflow interference of the interference (IoT) through the terminal whether the update period of the _{P0_CELL} value is a predetermined value. In one embodiment, it is determined whether the update period of the P 0 - _CELL value is 160 ms.

And if the update period of the P value _{0_CELL} predetermined value, in step (360a) compares the number (N) of the received overload indicators and the upper limit number (N _U). If the update period of the P 0 - _CELL value is not a predetermined value, the initialization is initialized to N = 0 again.

). If the lower limit number N _D is less than the number N of received overload indices, then in step 361a the cell performance value is decreased by the target received power as follows

).

If the upper limit number (N _U) is greater than the number (N) of the received overload indicator, and compares the number (N) of the received overload indicators and the lower limit of the number (N _D) in step (370a).

). 하한개수(N_D)가 상기 수신된 오버로드 지표의 수(N)보다 작은 경우에는 단계(372a)에서 상기 셀 성능 값을 유지 한다(

). If the lower limit number N _D is greater than the number N of received overload indices, then in step 371a the cell performance value is increased by the target received power

). If the lower limit number N _D is less than the number N of received overload indices, then in step 372a the cell performance value is maintained

).

In other words, the process of determining P _{0_Cell} based on the outflow interference counts the number of OI messages received by each cell during the update period of the specific time window of P _{0_Cell} , and the OI message received from N _U within a given time window In many cases, P _{0_Cell} is reduced by ΔP ₀ . On the other hand, if there are fewer OI messages received than N _{D in a} given time window, P _{0 - Cell} is increased by? P ₀ . If the OI message received over N _{D in a} given time window is larger, P ₀ remains constant. Here, ΔP ₀ is the amount of change in the target received power.

3B is a flowchart illustrating a process of determining a _{P0_UE} value based on an incoming interference according to an embodiment of the present invention.

In step 310b, an initial parameter of open loop-power control is set. For example, P _{O_CELL_min} = -7 dB and P _{O_CELL_max} = 8 dB are set, and IoT _TH is initialized.

At step 320b, the interference (IoT) through the terminal is averaged. IoT _{BS, i} and IoT _{UE, J} are averaged.

In step 330b, it is determined based on the input interference of the interference (IoT) through the terminal whether the update period of the _{P0_UE} value is a predetermined value. In one embodiment, it is determined whether the update period of the _{P0_UE} value is 80 ms.

If the update period of the _{P0_UE} value _satisfies a predetermined value, the _{P0_UE} value is calculated as follows in step 340b.

Here, P _{0_UE_max} and P _{0_UE_min} are set to 8 and -7 dB, respectively. PL _j is the pathloss between UE _j and the serving base station of UE _j , and PL _max is the representative pathloss for the cell edge user.

At this time, the value of? Is calculated as follows.

Here, IoT _{UE, j} is the uplink interference in the sub-band allocated to the user.

And, P if the update cycle is a predetermined value of _{0_UE} values match, and compares the interference (IoT), and the predetermined threshold _TH IoT through the terminal in step (350b).

If the interference (IoT) through the terminal is greater than the predetermined threshold IoT _TH , then in step 351b an overload indicator OI is transmitted to the interference cell.

If the interference (IoT) through the terminal is less than the predefined threshold IoT _TH , then in step 352b the overload indicator OI is not transmitted to the interference cell.

Referring again to FIG. 2, in step 250, a transmit power control command value having a transmit power set using parameters of open loop-power control is transmitted as follows.

In step 260, parameters of the transmit power control command are determined using the transmit power control command value. This will be described in more detail with reference to FIG.

5 is a flowchart illustrating a process of determining transmission power control command parameters according to an embodiment of the present invention.

The step of determining the parameters of the transmit power control command using the transmit power control command value first averages the received SINR (Rx SINR averaging), step 510.

In step 520, it is checked whether the period of the transmission power control command is updated.

If the period of the transmit power control command is updated, in step 530, the difference between the target SINR and the averaged received SINR is calculated as follows.

If the cycle of the transmit power control command has not been updated, the process moves again to step 510.

Then, the transmit power control command value according to the difference between the target SINR and the averaged received SINR is determined.

인지 판단한다.

인 경우, 전송 전력 제어 명령 값을

로 결정한다(541).In step 540,

.

, The transmit power control command value

(541).

이 아닌 경우, 단계(550)에서

인지 판단한다.

인 경우, 전송 전력 제어 명령 값을

로 결정한다(552).

, Then in step 550,

.

, The transmit power control command value

(552).

이 아닌 경우,

인지 판단한다.

인 경우, 전송 전력 제어 명령 값을

로 결정한다(562).

If not,

.

, The transmit power control command value

(562).

이 아닌 경우,

로 결정한다(570).

If not,

(570).

For example, determining the TPC command parameter f (i) averages the received SINR over 10ms. Thereafter, the base station calculates a difference ΔSINR that is the difference between the target SINR and the averaged received SINR.

The TPC value may be generated according to the following criterion.

If the received SINR does not meet the target SINR, the base station may send a positive TPC command value to the user to increase the transmit power. Otherwise, the base station may send a negative TPC command value to the user to reduce the transmit power.

Referring again to FIG. 2, in step 270, power headroom is reported according to the determined transmission power control command parameters (PH report).

Then, in step 280, the reported power headroom is used to calculate the dependent parameters of the modulation and coding scheme based on the modulation and coding scheme level selection. This will be described in more detail with reference to FIG.

4 is a flowchart illustrating a process of determining a dependent parameter of a modulation and coding scheme according to an embodiment of the present invention.

The step of calculating the dependent parameters of the modulation and coding scheme based on the modulation and coding technique level selection using the reported power headroom first averages the received SINR (Rx SINT averaging) in step 410.

In step 420, it is determined whether the dependent parameter of the modulation and coding scheme has been updated. If the dependent parameter of the modulation and coding scheme has been updated, then in step 430 an interference channel quality indication (I _CQI ) is determined. If the dependent parameter of the modulation and coding scheme has not been updated, the process moves to step 410 again.

Then, in step 440, it is determined whether there is a reported power headroom.

If the reported power headroom is present, update the interference channel quality indication according to the reported power headroom. If there is no reported power headroom, the process moves to step 471.

인지 판단한다.

인 경우, 단계(460)에서 간섭 채널 품질 표시

로 결정한다. At step 450

.

The interference channel quality indicator &lt; RTI ID = 0.0 &gt;

.

이 아닌 경우, 단계(470)에서

인지 판단한다.

인 경우, 단계(471)에서

를 유지한다.

이 아닌 경우에는 간섭 채널 품질 표시

로 결정한다.

, Then in step 470

.

, Then in step 471

Lt; / RTI &gt;

The interference channel quality indicator

.

At step 480, the dependent parameter &lt; RTI ID = 0.0 &gt; _MCS &lt; / RTI &gt; of the modulation and coding scheme is calculated as follows based on the interference channel quality indication I _CQI .

For example, the step of determining the MCS-dependent parameter [Delta] _MCS may be such that the received SINR is averaged over 10ms. The base station then determines the MCS level based on the averaged received SINR. Then, the user UE reports a negative PH, and the MCS level is determined to be one. At this time, the negative PH means that the UE transmission power is limited to the maximum. Therefore, the base station sends a negative offset to the user to reduce the transmission power of the user.

If no power headroom is reported, or if the reported power headroom value is zero, there is no change in the selected MCS level based on the received SINR.

If the user reports a positive PH, the MCS level generally selected based on the received SINR may be increased by one. At this time, the BS can consider that it is possible for the user to increase the transmission power of the user. If an appropriate MCS level for the data transmission is selected, then DELTA _MCS can be calculated.

6 is a diagram illustrating a configuration of an uplink power control system based on an interference recognition according to an embodiment of the present invention.

The interference recognition based uplink power control system may include an initialization unit 610, an allocation unit 620, an interference measurement unit 630, a parameter determination unit 640, a transmission unit 650, and a calculation unit 660 have. The initialization unit 610, the allocation unit 620, the interference measurement unit 630, the parameter determination unit 640, the transmission unit 650, and the calculation unit 660 perform the steps 210 to 280 of FIG. Lt; / RTI &gt;

The initialization unit 610 connects users to the network and initializes the closed loop-power control (CL-PC) parameter. Users UEs are connected to the network and the Closed Loop-Power Control (CL-PC) parameter can be initialized to zero. In other words, the RRC (Radio Resource Control) connection, the modulation and coding scheme dependent parameter? _MCS , and the transmission power control command parameter f (i) are initialized.

The allocator 620 allocates the PRB to the users. And allocates PRB = M to the user by using resource allocation schemes of 3GPP LTE-A.

The interference measurement unit 630 measures the interference (IoT) through the terminal for closed-loop power control and open loop-power control.

(F) Measures the interference occurring in the eNB. The base station (BS) i measures the interference over thermal (IoT) through the terminal as follows.

IoT _{BS, i} is the interference through the terminal is the uplink interference level in the total band allocated to the base station (BS) i. Thereafter, IoT _{BS, i} is allocated using a higher layer filter.

Then, the base station compares the averaged IoT _{BS, i} with the threshold IoT expressed by IoT _TH . If IoT _{BS, i} is higher than IoT _TH , an overload indicator (OI) message is reported to neighboring cells, otherwise report.

The parameter determiner 640 determines parameters of the open loop-power control and parameters of the transmit power control command using the transmit power control command value.

The parameter determiner 640 first sets an initial parameter of the open loop-power control, and determines whether the received overload indicator is received when the interference (IoT) through the terminal is higher than a predetermined threshold. When the overload indicator is received, it is determined based on the outflow interference of the interference (IoT) through the terminal whether the update period of the _PoCELL value is a predetermined value. If the update period of the _{P0_CELL} value is a predetermined value, the _{P0_CELL} value is updated according to the comparison result by comparing the number of users and the number of data with the number of the received overload indices.

Further, the parameter determiner 640 sets the initial parameters of the open loop-power control and averages the interference (IoT) through the terminal. If it is determined, based on the incoming interference of the interference (IoT) through the terminal an update cycle of P _{0_UE} value matches the predetermined value, the update period of the P _{0_UE} value is a predetermined value suitable to calculate the P _{0_UE} value . Then, the interference (IoT) through the terminal is compared with a predetermined threshold value.

 Transmitter 650 transmits the transmit power control command value having the set transmit power using the parameter of the open loop-power control, and reports the power headroom according to the determined transmit power control command parameter.

The calculation unit 660 calculates the dependent parameters of the modulation and coding scheme based on the modulation and coding scheme level selection using the reported power headroom.

The calculation unit 660 averages the received SINR and determines whether the dependent parameter of the modulation and coding scheme is updated. When the dependent parameter of the modulation and coding scheme is updated, an interference channel quality indication is determined. Thereafter, if there is the reported power headroom, then the interferer channel quality indicator is updated according to the reported power headroom. And calculates dependent parameters of the modulation and coding scheme based on the interference channel quality indication.

The proposed PHR-PERA efficiently utilizes limited bandwidth and power resources by allocating PRBs to users considering user power capacity. Additionally, the OL-PC is applied to improve the capacity of macros and femtocells by setting open-loop parameters based on the average received SINR and uplink interference caused by neighboring cells. By applying this proposed uplink power control scheme, cell capacity can be maximized despite severe interference conditions in 3GPP LTE-A HetNet environment. In addition, by using the OL-PC supported by the CL-PC based on the PHR and the received SINR, the user uplink SINR meets the target SINR requested by the base station using OL-PC only through compensation of the fading effect can do.

The apparatus described above may be implemented as a hardware component, a software component, and / or a combination of hardware components and software components. For example, the apparatus and components described in the embodiments may be implemented within a computer system, such as, for example, a processor, a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable array (FPA) A programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions. The processing device may execute an operating system (OS) and one or more software applications running on the operating system. The processing device may also access, store, manipulate, process, and generate data in response to execution of the software. For ease of understanding, the processing apparatus may be described as being used singly, but those skilled in the art will recognize that the processing apparatus may have a plurality of processing elements and / As shown in FIG. For example, the processing unit may comprise a plurality of processors or one processor and one controller. Other processing configurations are also possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of the foregoing, and may be configured to configure the processing device to operate as desired or to process it collectively or collectively Device can be commanded. The software and / or data may be in the form of any type of machine, component, physical device, virtual equipment, computer storage media, or device , Or may be permanently or temporarily embodied in a transmitted signal wave. The software may be distributed over a networked computer system and stored or executed in a distributed manner. The software and data may be stored on one or more computer readable recording media.

The method according to an embodiment may be implemented in the form of a program command that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions to be recorded on the medium may be those specially designed and configured for the embodiments or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. For example, it is to be understood that the techniques described may be performed in a different order than the described methods, and / or that components of the described systems, structures, devices, circuits, Lt; / RTI &gt; or equivalents, even if it is replaced or replaced.

Therefore, other implementations, other embodiments, and equivalents to the claims are also within the scope of the following claims.

Claims (12)

An interference-aware uplink power control method,
Users are connected to the network and initializing closed loop-power control (CL-PC) parameters;
Assigning PRBs to the users;
Measuring interference (IoT) due to the terminal for the closed-loop power control and open loop-power control;
Determining parameters of the open loop-power control;
Transmitting a transmit power control command value having a set transmit power using the parameters of the open loop-power control;
Determining a parameter of a transmission power control command using the transmission power control command value;
Reporting power headroom according to the determined transmission power control command parameters; And
Calculating a dependent parameter of the modulation and coding scheme based on the modulation and coding technique level selection using the reported power headroom,
Wherein the interference-aware uplink power control method comprises: The method according to claim 1,
Wherein determining the parameters of the open loop-power control comprises:
Setting an initial parameter of the open loop-power control;
Determining if a received overload indicator is received if the interference due to the terminal (IoT) is higher than a predetermined threshold;
Updating the number of overload indices and determining whether the update period of the cell related value among the target received power is a predetermined value when the overload indicator is received;
Comparing the number of the overload indicators with the predetermined number of overload indicators and the number of the overload indicators when the update period of the cell related value among the target received power is a predetermined value; And
Updating a cell-related value of the target received power according to the comparison result
Wherein the interference-aware uplink power control method comprises: 3. The method of claim 2,
The step of updating the cell-related value of the target received power according to the comparison result comprises:
The cell-related value of the target received power is higher than the count number of the received overload indicator upper limit to reducing power by ΔP ₀ Step
Wherein the uplink power control method is based on interference. 3. The method of claim 2,
The step of updating the cell-related value of the target received power according to the comparison result comprises:
If the received overload index number is smaller than the lower limit number, increasing the cell-related value of the target received power by the? P ₀ step power
Wherein the uplink power control method is based on interference. The method according to claim 1,
Wherein determining the parameters of the open loop-power control comprises:
Setting an initial parameter of the open loop-power control;
Averaging the interference (IoT) caused in the band assigned to the terminal;
Determining whether an update period of the user related value among the target received powers is a predetermined value;
Calculating a user-related value of the target received power if the update period of the user-related value of the target received power meets a predetermined value; And
Comparing the interference (IoT) caused in the band assigned to the terminal with a predetermined threshold value when the update period of the user related value of the target received power meets a predetermined value
Wherein the interference-aware uplink power control method comprises: 6. The method of claim 5,
Calculating a user-related value of the target received power using a value obtained by comparing an interference (IoT) caused by the terminal with a predetermined threshold value if the update period of the user-related value of the target received power meets a predetermined value ,
Wherein the interference-aware uplink power control method comprises: The method according to claim 1,
Wherein the determining the parameters of the transmit power control command using the transmit power control command value comprises:
Averaging the received SINR;
Confirming whether the period of the transmission power control command is updated;
Calculating a difference between a target SINR and the averaged received SINR; And
Determining a transmit power control command value according to a difference between a target SINR and the averaged received SINR
Wherein the interference-aware uplink power control method comprises: The method according to claim 1,
Wherein calculating the dependent parameters of the modulation and coding scheme based on modulation and coding technique level selection using the reported power headroom comprises:
Averaging the received SINR;
Determining whether the dependent parameter of the modulation and coding scheme has been updated;
Determining an interference channel quality indication if the dependent parameter of the modulation and coding technique is updated;
Checking if the reported power headroom is present;
Updating the interference channel quality indication according to the reported power headroom if the reported power headroom is present; And
Calculating a dependent parameter of the modulation and coding scheme based on the interference channel quality indication
Wherein the interference-aware uplink power control method comprises: An interference-aware uplink power control system,
An initialization unit to which users are connected to the network and initialize the closed loop-power control (CL-PC) parameter;
An allocation unit for allocating PRBs to the users;
An interference measurement unit for measuring interference (IoT) through the terminal for the closed-loop power control and open loop-power control;
A parameter determining unit that determines parameters of the open loop-power control and determines parameters of a transmit power control command using a transmit power control command value;
A transmission unit for transmitting a transmission power control command value having a transmission power set using the parameters of the open loop-power control, and reporting power headroom according to the determined transmission power control command parameter; And
A calculation section for calculating a dependent parameter of the modulation and coding scheme based on the modulation and coding scheme level selection using the reported power headroom,
Based on the received power control information. 10. The method of claim 9,
Wherein the parameter determination unit comprises:
Setting an initial parameter of the open loop-power control and determining whether an overload indicator received when the interference (IoT) through the terminal is higher than a predetermined threshold is received and, if the overload indicator is received, Determining whether the update period of the cell related value of the target received power is a predetermined value based on the outflow interference of the interference (IoT) through the terminal, and when the update period of the cell related value of the target received power is a predetermined value, Comparing the number of users and the number of data with the number of overload indications received and updating a cell-related value of the target received power according to the comparison result
Wherein the power control system comprises: 10. The method of claim 9,
Wherein the parameter determination unit comprises:
Determining an update period of the user-related value of the target received power according to a predetermined value, setting an initial parameter of the open loop-power control, averaging the interference (IoT) caused by the terminal, Calculating a user-related value of the target received power if the update period of the value meets a predetermined value, and comparing the interference (IoT) through the terminal with a predetermined threshold
Wherein the power control system comprises: 10. The method of claim 9,
The calculation unit may calculate,
Determining an interference channel quality indication when the dependent parameter of the modulation and coding scheme is updated by determining whether the dependent parameter of the modulation and coding scheme has been updated to average the received SINR and determining whether the reported power headroom is present Updating the interference channel quality indication according to the reported power headroom and calculating a dependent parameter of the modulation and coding scheme based on the interference channel quality indication if there is the reported power headroom
Wherein the power control system comprises:

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