WO2012174967A1

WO2012174967A1 - Coordinated multipoint transmission method, system, terminal device, and base station device

Info

Publication number: WO2012174967A1
Application number: PCT/CN2012/075897
Authority: WO
Inventors: 贺抗生; 黄双红; 王文焕; 刘敏
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-20
Filing date: 2012-05-22
Publication date: 2012-12-27
Also published as: CN102843715A; CN102843715B

Abstract

The technical problem to be solved by embodiments of the present invention is to provide a coordinated multipoint transmission method, system, terminal device, and base station device. The method comprises: a terminal device performing measurement, and sending a measurement result to a base station; the base station estimating, according to the measurement result sent by the terminal device, a channel quality indication (CQI) value of a data stream transmitted by each measured cell when the measured cell coordinates with other measured cells, and selecting, according to the CQI value of each measured cell, a measured cell coordinating to send service data to the terminal device. The method and system can realize multi-stream coordinated transmission.

Description

Multipoint coordinated transmission method, system, terminal device and base station device

Technical field

The present invention belongs to the field of wireless communications, and in particular, to a multipoint coordinated transmission method, system, terminal device and base station device.

Background technique

In order to improve the throughput of the system and solve the problem of interference at the cell edge, the long-term evolution advance (LTE-Advance) considers the introduction of Coordinated multipoint transmission (CoMP) and has carried out extensive discuss.

The multi-point cooperation technology can be divided into two types: joint processing (JP), Coordinated Scheduling (CS) or Coordinated Beamforming (CB). For JP, data can be obtained for each node in the collaborative set, and JP can be further divided into Joint Transmission (JT) and Dynamic Cell Switching (DCS); for CS/CB The data is only available in the serving cell, and the data is transmitted by the serving cell, but the scheduling of the user and the determination of the beam are jointly determined by the plurality of cells in the cooperative set according to the conditions of the channel.

Among the CoMP transmission schemes currently under discussion, the JP transmission methods are mainly divided into two categories, related cooperative transmission schemes and non-correlated cooperative transmission schemes. The related cooperative transmission scheme is divided into a global precoding scheme, a phase correction plus precoding scheme, and a BF (Beamforming) based precoding scheme; the uncorrelated cooperative transmission scheme is further divided into independent precoding schemes, based on The transmission scheme of the Space Frequency Block Code (SFBC), the transmission scheme based on Cyclic Delay Diversity (CDD), and the transmission scheme based on SFN (Single Frequency Network).

The MIMO system constructs parallel spatial channels. Through these parallel spatial channels, independent spatial channels can be characterized by rank. The number of data layers transmitted by the MIMO channel cannot be greater than the channel rank. The rank can be used to determine the number of layers of data transmission. For users at the cell edge, the rank of the channel tends to be higher than the channel condition. Smaller, when transmitting in a single cell, the application scenario of multi-antenna (MIMO) is mainly a single-layer transmission with rank 1, while if multiple coordination points (ie, coordinated cells) participate in cooperative transmission, or participate in cooperative user terminals ( UE, user equipment) is not limited to users at the edge of the cell, and may increase the Signal to Interference pus Noise Ratio (SINR) and the number of conditions of the channel, so that the channel rank is 2 or the number of ranks is more. In the case of the current discussion, the scheme is mainly based on the single layer transmission with rank equal to 1, and no detailed solution is given for the scene with rank greater than 1.

In addition, in the case of single cell transmission, the data of the user terminal is transmitted by a single base station, and the distance between each antenna and the user terminal is generally considered to be the same, so the time difference between the data of each antenna reaching the user is small, negligible, and will not be It has a big impact on the performance of the user. For the cell edge, in the case of multi-point cooperation, the distance from different cells to the UE may be very different, and the delay of data of different cells reaching the target UE may be very different, and this delay may even exceed the loop in the OFDM symbol. The length of the prefix (Cyclic prefix, CP for short), which causes interference between OFDM symbols. The problem of different arrival delays in small intervals has been studied in depth. In fact, this problem actually causes JT's advantages to be difficult to play, requiring important research and analysis and effective solutions. In the current multi-point collaboration scheme, no specific solutions are given for the adverse effects of the delay problem. Summary of the invention

The technical problem to be solved by the embodiments of the present invention is to provide a multipoint coordinated transmission method, system, terminal device, and base station device, which can implement multi-stream cooperative transmission.

To solve the above technical problem, an embodiment of the present invention provides a multipoint coordinated transmission method, including:

The terminal device performs measurement, and sends the measurement result to the base station;

The base station predicts, according to the measurement result sent by the terminal device, the channel quality indicator (CQI) value of the data stream transmitted by the measurement cell when each measurement cell cooperates with other measurement cells, and selects a collaboration according to the CQI value of each measurement cell. A measurement cell that transmits service data to the terminal device.

Optionally, the measuring, by the terminal device, includes: The terminal device measures the following: the power of the neighboring cell leaking to the terminal, the power of the serving cell to the terminal, and the sum of the interference power and the noise power outside the measured cell set;

The terminal device sends the measurement result to the base station, including:

The terminal device transmits the sum and the measurement result to the base station; or

a ₌ A.

The terminal device sends ^ as a measurement result to the base station, 'w. The power of the neighboring cell leaks to the terminal and the power of the serving cell to the local terminal, where the measured is the sum of the interference power and the noise power outside the cell set, and i represents the index of the cell.

Optionally, the content measured by the terminal device further includes: a delay of each measurement cell to the local service serving cell, where the terminal device sends the time delay to the base station;

After determining, by the base station, the measurement cell that sends the service data to the terminal device, the base station acquires a compensation factor corresponding to the delay of each neighboring cell in the measurement cell that sends the service data to the terminal device, where the compensation factor is used. Each measurement cell that transmits service data to the terminal device compensates the service data in the frequency domain when transmitting the service data to the terminal device.

Optionally, after measuring the delay of each neighboring cell to the serving cell of the terminal, the terminal device sends the time-quantified value to the base station.

Optionally, the compensating the service data in the frequency domain includes: multiplying the service data to be transmitted, ^{2 π ω} , where: ω is a compensation factor.

Optionally, the step of the base station predicting, by each base station, the CQI value of the data stream transmitted by the measurement cell when the measurement cell cooperates with other measurement cells includes:

The base station uses the following formula to calculate the CQI corresponding to the data stream respectively transmitted by the two measurement cells when the measurement cell m cooperates with the measurement cell η:

COI = ~ ^ ~ = ^ COI = ~ ^ ~ = _{Γ 1}

· " Ρ _Π ^{+ Ν} . ' ^M P _M ^{+ N} . where ^L denotes the CQI of the data stream transmitted by the cell m in the case where the measurement cell m cooperates with the measurement cell n, and ^C2 " indicates that the measurement cell m cooperates with the measurement cell n The CQI of the data stream transmitted by the lower cell n.

Optionally,

The base station calculates the measurement cell m by using the following formula, and the measurement cell n is in agreement with the measurement cell 1 When doing so, the CQI corresponding to the separately transmitted data stream:

CQI QOI = ~ ^ ^ = _ ^ _ f

"■"P _{1 +} N. - a _{1 +} \ , VTM P^ + N, + «„+ l , where the measurement cell, the measurement cell and the measurement cell Z cooperate to measure the cell and the measurement cell” The CQI of the transmitted data stream, ^C2 represents the measured CQI of the data stream transmitted by the cell Z when the measurement cell, the measurement cell, and the measurement cell Z cooperate.

Optionally, the step of selecting, by the base station, the measurement cell that sends the service data to the terminal device according to the CQI value of each measurement cell includes:

The base station selects the measurement cell corresponding to the optimal set of CQI values as the measurement cell that transmits the service data to the terminal device according to the calculated CQI value.

Optionally, when the measured cell that sends the service data to the terminal device includes the current serving cell, the current serving cell is configured to transmit the control channel and the service data of the terminal to the terminal device, where The neighboring cell in the measurement cell that transmits the service data to the terminal device is used to transmit the service data of the terminal to the terminal device;

When the measured cell that sends the service data to the terminal device does not include the current serving cell, the current serving cell is configured to transmit the control channel of the terminal to the terminal device, and the selected cooperation is sent to the terminal device. The neighboring cell in the measurement cell of the service data is used to transmit the service data of the terminal to the terminal device.

Optionally, the current serving cell and the neighboring cell in the measurement cell that the cooperation to send the service data to the terminal device use the same or different number of antennas when transmitting data to the terminal device.

To solve the above technical problem, an embodiment of the present invention further provides a multipoint coordinated transmission system, including a measurement module, and a coordinated cell selection module, where:

The measurement module is located at the terminal device, configured to perform measurement, and send the measurement result to the coordinated cell selection module;

The coordinated cell selection module is located at the base station, and is configured to, according to the measurement result sent by the terminal, predict, by each measurement cell, a channel quality indicator (CQI) value of the data stream transmitted by the measurement cell when cooperating with other measurement cells, according to The CQI value of each measurement cell is selected to cooperate with the terminal. A measurement cell that is ready to send traffic data.

In order to solve the above technical problem, an embodiment of the present invention further provides a terminal device for implementing coordinated multi-point transmission, including a measuring unit and a feedback unit, where:

The measuring unit is configured to measure the following: the power of the neighboring cell leaking to the terminal, the power of the serving cell to the terminal, and the sum of the interference power and the noise power outside the measured cell set; the feedback unit is set to The measurement result is sent to the base station.

To solve the above technical problem, an embodiment of the present invention further provides a base station apparatus for implementing coordinated multi-point transmission, including a receiving unit, a calculating unit, and a coordinated cell selecting unit:

The receiving unit is configured to receive a measurement result sent by the terminal;

The calculating unit is configured to predict a channel quality indicator (CQI) value of the data stream transmitted by the measurement cell when each measurement cell cooperates with other measurement cells;

The coordinated cell selection unit is configured to select a measurement cell that cooperatively transmits service data to the terminal device according to a CQI value of each measurement cell.

The technical solution of the embodiment of the present invention can implement coordinated transmission to the user terminal under the complicated channel condition of the cell edge, improve the data transmission rate of the cell edge user, and determine the optimal coordinated cell by simple feedback of the user terminal. The CQI of each data stream transmitted to the user terminal is calculated. In addition, the user terminal measures the delay of each measurement cell and feeds back to the base station, so that different coordinated cells can perform frequency domain compensation according to the delay, which can effectively overcome the disadvantages caused by different delays of each coordinated cell. Impact, improve the performance of the community edge to participate in collaborative users. BRIEF abstract

1 is a schematic structural diagram of a system according to an embodiment of the present invention;

2 is a schematic structural diagram of a terminal device according to an embodiment of the present invention; 3 is a schematic structural diagram of a base station apparatus according to an embodiment of the present invention;

4 is a flow chart of an embodiment of the present invention;

Figure 5 is a schematic view of an application example 1 of the present invention;

Figure 6 is a schematic view of an application example 2 of the present invention;

Fig. 7 is a schematic view showing an application example 3 of the present invention. Preferred embodiment of the invention

The embodiment of the present invention provides a cell cooperative transmission method including:

The base station predicts, according to the measurement result sent by the terminal, the CQI (Channel Quality Indicator) value of the data stream transmitted by the cell when the measurement cell cooperates with other measurement cells, and selects the cooperation direction according to the CQI value of each measurement cell. The terminal device transmits a measurement cell of service data.

The measured cell in which the selected cooperation transmits the service data to the terminal device may be recorded in the cell cooperation set of the terminal, and these measurement cells are referred to as coordinated cells. The selected measurement cell will collaborate to transmit data to the terminal.

Optionally, the terminal device may further calculate a delay of each measurement cell (the measurement cell includes a neighboring cell and a serving cell) to the local serving cell (i denotes an index of the measurement cell), and send the delay information to the base station. After determining the measurement cell that sends the service data to the terminal device, the base station acquires a compensation factor ω corresponding to the delay of each neighboring cell in the measurement cell that transmits the service data to the terminal device, and the compensation factor is used for each collaboration. The measurement cell that transmits the service data to the terminal device compensates the service data in the frequency domain when transmitting the service data to the terminal device (mainly, the neighboring cell in the measurement cell compensates the service data). That is, the neighboring cells in the measurement cell that jointly transmit the service data to the terminal device transmit the service data to the terminal, and use the compensation factor to compensate the service data in the frequency domain. The following methods can be used to compensate: multiply the service data to be transmitted by ( ^{π ω} , each cooperative cell can offset the adverse effects caused by the delay by compensating the service data in the frequency domain. In order to reduce the feedback content, the terminal can time The quantized value is sent to the base station.

The terminal may measure the following periodically or non-periodically: the neighboring cell leaks to the terminal Power, the power of the serving cell to the terminal, and the sum of the interference power and the noise power outside the measured cell set.

The terminal device transmits the sum as a measurement result to the base station; or the terminal device transmits the ^ as a measurement result to the base station, ' ^Ν

The power of the neighboring cell leaks to the terminal and the power of the serving cell to the local terminal, where the measured is the sum of the interference power and the noise power outside the cell set, and i represents the index of the cell.

When the terminal will be A and ^N. When transmitting as a measurement result to the base station, the base station can be based on ^ and ^N. Calculation

CQI; When the terminal transmits the measurement result to the base station, the base station can directly calculate the CQI according to the α of each cell, and the terminal only transmits α to reduce the feedback amount.

The base station can select any one of the following two ways to predict the CQI value of the data stream transmitted by the measurement cell when each measurement cell cooperates with other measurement cells.

method one

The base station only calculates the CQI when any two cells cooperate. The base station calculates the CQI corresponding to the data stream respectively transmitted by the two measurement cells when the measurement cell m cooperates with the measurement cell η as follows:

If the measurement result sent by the terminal includes and , the base station calculates the CQI using the following formula:

P _n + Nτ ₀ , ^c Q ^J _n , P _m + N ₀

If the measurement result sent by the terminal includes, the base station calculates the CQI using the following formula: a _n + 1 a _m + 1

Wherein Cg / ^ m represents the CQI transmission in the case of cell-cell and cell n _m collaboration data stream, ^C2 "represents the CQI transmission data n the case of cell-cell and cell n m collaboration stream., And ^ ^^^" For a group of CQIs, the measurement cell corresponding to the group of CQIs includes a cell m and a cell n.

Way two

The base station calculates the CQI when any two and any three cells cooperate. The base station uses the formula in the first method to calculate the CQI when any two cells cooperate. In addition, the base station calculates and measures the following manner. The CQI corresponding to the data stream respectively transmitted by the measurement cell n and the measurement cell n when cooperating with the measurement cell 1: If the measurement result sent by the terminal includes the sum, the base station calculates the CQI by using the following formula:

p + p p,

CQI _mn , i = _n , , _r , CQI leg =

Pt + N ₀ - P _m + P _n + N ₀

If the measurement result sent by the terminal includes, the base station calculates the CQI using the following formula:

Α +1 c _m + _n + \

Wherein, the CQI (the same data stream transmitted by the measurement cell ^m and the measurement cell) of the data stream jointly transmitted by the measurement cell, the measurement cell and the measurement cell/measurement cell in the measurement cell/collaboration case is the same, indicating that the measurement cell is The measurement cell "measures the CQI of the data stream transmitted by the cell Z in the case of measurement cell cooperation. ^CQI ^' and e^', TM is a group of CQIs, and the measurement cells corresponding to the group CQI include cell m, cell n, and cell 1.

The base station selects, according to the CQI value of each measurement cell, a measurement cell corresponding to an optimal set of CQI values as a measurement cell that cooperatively transmits service data to the terminal device. For example, the base station determines the optimal group according to the calculated ", CQI, _C2, and _C2; (^ is and ^, the base station selects the measurement cells m, n, and 1 as a measure of cooperatively transmitting service data to the terminal device. If the base station receives the delay sent by the terminal, the frequency domain compensation factor corresponding to the delay of the cell to the terminal corresponding to the CQI of the set of values is calculated and ^ω "and.

After selecting the coordinated cell, the serving cell of the terminal uses the service data, the downlink resource allocation mode of the terminal, the downlink resource allocation, the logical port information of the demodulation pilot used, the modulation and coding scheme, and the CRNTI (Cell Radio Network) corresponding to the terminal. Temporary Identifier, information such as the frequency domain compensation factor corresponding to the coordinated transmission point, is sent to other coordinated cells except the serving cell.

If the selected coordinated cell includes the current serving cell, the current serving cell is configured to transmit the control channel and service data of the terminal to the terminal device, where the neighboring cell in the selected coordinated cell is used to transmit the terminal to the terminal device. Business data;

If the selected cell does not include the current serving cell, the current serving cell is used to transmit the control channel of the terminal to the terminal device, and the neighboring cell in the selected coordinated cell is used to set the terminal to the terminal. The service data of the terminal is transmitted. For example, a neighboring cell in the coordinated cell performs coding, modulation, mapping, and frequency domain compensation on the service data according to the information sent by the serving cell, and generates a demodulation pilot sequence and a mapping according to the demodulation pilot logical port information sent by the serving cell. . The user terminal detects the control channel and parses the service data according to the indication of the control channel. For the user terminal, it does not know which cooperation point the service data is sent by, and the transmission of the service data is transparent to the user terminal.

The number of antennas used by the current serving cell and the neighboring cell in the coordinated cell when transmitting data to the terminal device is the same or different.

The system for implementing the above method is shown in FIG. 1, and includes a measurement module 101 and a coordinated cell selection module 102, where:

The measurement module 101 is located at the terminal device, configured to perform measurement, and send the measurement result to the coordinated cell selection module;

The coordinated cell selection module 102 is located at the base station, and is configured to: according to the measurement result sent by the terminal, predict, when each measurement cell cooperates with other measurement cells, the CQI value of the data stream transmitted by the measurement cell, according to each measurement cell The CQI value selects a measurement cell that cooperates to transmit service data to the terminal device.

The measurement module 101 is configured to measure the following: the power leaked by the neighboring cell to the terminal, the power of the serving cell to the terminal, and the sum of the interference power and the noise power outside the measured cell set;

The measurement module 101 is configured to send the measurement result to the coordinated cell selection module in the following manner:

And the measuring module 101 transmits a measurement result as to the coordinated cell selection module; terminal or present the measuring module 101 ^ cooperative transmission cell as the measurement result to the selection ^module, 'Ν wherein the leakage for the adjacent cell The power and the power of the serving cell to the local terminal, the measured interference power and the noise power outside the cell set, i represents the index of the cell. Optionally, the coordinated cell selection module 102 is configured to predict the CQI value of the data stream transmitted by the measurement cell when each measurement cell cooperates with other measurement cells in the following manner:

The coordinated cell selection module 102 calculates, by using the following formula, the CQI corresponding to the data stream respectively transmitted by the two measurement cells when the measurement cell m cooperates with the measurement cell n:

P a

_{_{P n + N 0 «" +}} l, "P m + N 0 + i, where CG ^ represents the CQI m transmission cell case of cell _m and cell n collaboration data stream, ^C2" denotes a cell m and cell n Collaboration The CQI of the data stream transmitted by cell n.

Alternatively, in addition to the CQI of the two-cell cooperation calculated above, the following formula is used to calculate the CQI corresponding to the data stream respectively transmitted by the measurement cell m and the measurement cell n when cooperating with the measurement cell 1:

P +P a + P, a,

^ +No a _{l +} l , P _m +P _n +N ₀ a _m + a _n +l ^ where CQI _mnJ denotes measurement cell ^m , measurement cell "measurement cell m and measurement cell in case of measurement cell Z cooperation" The CQI of the jointly transmitted data stream, e^''TM represents the CQI of the measurement cell TM, the measurement cell" and the measurement cell coordinated measurement of the data stream transmitted by the cell.

The coordinated cell selection module 102 selects a measurement cell corresponding to an optimal set of CQI values as a measurement cell that transmits service data to the terminal device in cooperation.

The terminal device implementing the above method, as shown in FIG. 2, includes a measuring unit 201 and a feedback unit 202, where:

The measuring unit 201 is configured to measure the following: the power of the neighboring cell leaking to the terminal, the power of the serving cell to the terminal, and the sum of the interference power and the noise power outside the measured cell set; the feedback unit 202 is set to The measurement result is sent to the base station.

Optionally, the measuring unit 201 is further configured to measure a time delay of each measurement cell to the local serving cell; the feedback unit 202 is further configured to send the time delay obtained by the measuring unit to the base station.

Optionally, the measuring unit 201 is further arranged to quantize the measured time delay.

Optionally, the feedback unit 202 is configured to send the measurement result to the base station in the following manner: the feedback unit 202 sends the sum as a measurement result to the base station; or The feedback unit 202 transmits a measurement result to the base station, ^N o; wherein the power leaked to the terminal of the present serving cell and each neighboring cell according to the power terminal, the interference power measurement cell set outside And the sum of the noise powers, i represents the index of the cell.

As shown in FIG. 3, the base station apparatus implementing the above method includes a receiving unit 301, a calculating unit 302, and a coordinated cell selecting unit 303:

The receiving unit 301 is configured to receive the measurement result sent by the terminal;

The calculating unit 302 is configured to predict a channel quality indicator (CQI) value of the data stream transmitted by the measurement cell when each measurement cell cooperates with other measurement cells;

The coordinated cell selection unit 303 is configured to select a measurement cell that cooperatively transmits service data to the terminal device according to a CQI value of each measurement cell.

Optionally, the calculating unit 302 may only calculate the CQI when any two cells cooperate, and in addition, the calculating unit may also calculate the CQI when any three cells cooperate. The specific formula is as described above, and will not be described here. The coordinated cell selection unit selects a measurement cell corresponding to the optimal set of CQI values as a measurement cell that cooperatively transmits service data to the terminal device according to the CQI value calculated by the calculation unit.

Optionally, the receiving unit 301 is further configured to receive a delay of each measurement cell to the serving cell of the terminal;

The apparatus further includes a compensation factor determining unit 304 configured to: after the coordinated cell selection unit determines a measurement cell that cooperatively transmits the service data to the terminal device, acquire each phase in the measurement cell that cooperates to transmit the service data to the terminal device. A compensation factor corresponding to the delay of the neighboring cell, where the compensation factor is used by each measurement cell that transmits the service data to the terminal device to compensate the service data in the frequency domain when transmitting the service data to the terminal.

In order to make the objects, the technical solutions and the advantages of the present invention more clearly, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that in the absence of conflict, this application The features of the embodiments and the embodiments may be arbitrarily combined with each other.

FIG. 4 is a flowchart of a multi-point cooperative transmission scheme according to an embodiment of the present invention. As shown in FIG. 4, the transmission scheme includes the following steps:

Step S401: The user terminal periodically or aperiodically measures the channel condition of each possible coordinated cell to the local terminal at a predetermined time, and the measurement may be performed by using a CSI-RS, and the measured content includes that each neighboring cell leaks to the terminal. Power and service d, the power from the zone to the terminal (i indicates the cell index), the sum of interference and noise outside the measurement set, the delay from the cell in each measurement set to the terminal relative to the primary serving cell, and Calculate the feedback coefficient based on the calculated sum

And wherein the feedback of the user terminal to the base station may be periodic or non-periodic, and may be configured by the base station;

Step S403: The base station receives the information fed back by the user terminal, and calculates the CQI in the cooperation situation of each cell according to the feedback. For the coordinated cells m and n, the cell cooperates in the case of cooperation.

CQi^ _n =^- CQI _nm =-

. (^^^^ and ^" , where a +l and 3 community associations

P _m +P„ a _m + a„ The CQI values CQI _mnJ and CQ where CQI^ :

Step S404: The base station determines, according to the calculated CQI value, a group of optimal C2/^ and Cg/^ or _C2 and _C2 ^, and the cells corresponding to the optimal CQI of the group (such as cells m and n, Alternatively, n, /) as the optimal transmission point, and calculates a compensation factor based on the cell delay feedback terminal (e.g., a cooperating cell is a cell _∞, n, I, n is calculated based on the cell corresponding to each of three cell delay , / corresponding frequency domain compensation factor, ^ω _ωι ); frequency domain transform for delay can obtain frequency domain compensation factor, a correspondence table of delay and compensation factor can be preset, and the frequency domain corresponding to delay is obtained by looking up the table Compensation factor.

Step S405: According to the coordinated cell selected in step S404, the primary serving cell uses the cell, the cell, the transmitted cell, the downlink resource allocation mode, the downlink resource allocation, the logical port information of the demodulation pilot used by the terminal, and the modulation and coding. Solution, terminal CRNTI, collaboration point Information such as a corresponding frequency domain compensation factor is sent to the cooperative cell m, n , /;

Step S406: The primary serving cell transmits the control channel of the terminal, and the coordinated transmission point encodes, modulates, maps, and compensates the service data according to the information sent by the primary serving cell, according to the demodulation pilot logical port sent by the primary serving cell. Information generating demodulation pilot sequences and mapping;

The primary serving cell may serve as a transmission point for the service data, or may not transmit only the control channel as a transmission point of the service data. When the primary serving cell serves as the transmission point of the service data, the primary serving cell does not need to perform frequency domain compensation, and the compensation factor of the primary serving cell in the frequency domain may be considered to be zero. The user terminal detects the control channel and parses the service data according to the indication of the control channel. For the user terminal, it does not know which cooperation point the service data is sent by, and the transmission of the service data is transparent to the user terminal, and each coordinated transmission is performed. The number of antenna ports of the point may be the same or different.

Application example 1

As shown in FIG. 5, for the target terminal, three cells are considered to be measured, and the primary serving cell is Cell#0 (for the sake of simplicity, the cell with the cell ID n is described as Cell#n), and other measurements are performed. The cells are Cell#l and Cell#2. The implementation steps are as follows:

The first step, the target terminal measurement to obtain a primary serving cell including a measurement cell including a power terminal to the present ^Ρ. , and the sum of interference and noise of the cell outside the measurement set, and the delay of Cell#1 and Cell#2 to the terminal relative to the primary serving cell Cell#0;

Ρ ₀ Ρ _λ Ρ _{2 In the} second step, the target terminal calculates the feedback coefficient ".," ι , "2 , where ° N., ¹ N., ² N., calculates the delay ^ corresponding to the quantized index value;

In the third step, the target terminal feeds back the index value of ".," ² and the delay quantized to the base station; in the fourth step, the primary serving cell Cell#0 receives the feedback from the target terminal "., "1," ² and After the quantized index value, the CQI in the case of cell cooperation is calculated, and ^{C2 is} obtained, i, ^CQI , ^CQI ° ² , ^CQI ^ , ^CQI ^ , ^CQI " , and CQI under the cooperation of three cells: CQI _{m 2} , CQI _{2 m} , CQI , CQI _l02 , CQI _no , CQI _on ; The primary serving cell Cell #0 selects a set of optimal CQI values, and uses the optimal group of CQI corresponding cells as the coordinated cell, as shown in the figure. 5, choose The optimal transmission points are Cell#l and Cell#2, and the frequency domain compensation factors corresponding to Cell#l and Cell#2 are calculated from the feedback delay index;

In the fifth step, the primary serving cell Cell#0 uses the service data TBI (transport block 1), the TBI corresponding modulation and coding scheme (obtained), the resource allocated by the TBI, and the logic of the demodulation pilot used for transmitting the TBI. Port information (for example, Port7), the CRNTI of the frequency domain compensation factor terminal is sent to Cell#1; Cell#0 is the modulation coding scheme corresponding to the service data TB2, TB2 (according to ^3⁄4^), the resource condition allocated by TB2, Transmitting the logical port information of the demodulation pilot used by TB2 (for example, Port8), and transmitting the CRNTI of the frequency domain compensation factor terminal to Cell#2; this step is suitable for Intra-eNB (inter-base station cooperation) and inter-eNB (inter-base station) Collaboration) In both cases, for intra-eNB, data and other information can be sent directly by Cell#0 and Cell#2. For inter-eNB, data and other information can be transmitted through X2 port or extended. The X2 port is sent to Cell#l and Cell#2.

In the sixth step, the primary serving cell Cell#0 transmits a control channel to the terminal, and Cell#1 maps the DM-RS according to the DM-RS (demodulation pilot) logical port information sent by Cell#0, Cell#l According to the TBI modulation and coding scheme sent by Cell#0, the terminal CRNTI performs modulation and coding scrambling frequency domain compensation mapping on the TBI, and the data in the frequency domain compensation of the TBI precoded data is S; Cell#2 according to Cell #0 sent DM-RS logical port information, mapping DM-RS, Cell#2 is based on the modulation and coding scheme of TB2 sent by Cell#0, and the terminal CRNTI performs modulation and coding scrambling frequency domain compensation mapping on TB2. For the data of the TB2 pre-coded data frequency domain, the user terminal detects the control channel and parses the service data according to the indication of the control channel. For the user terminal, it does not know which cooperation point the service data is sent by. The transmission of the service data is transparent to the user terminal. In this embodiment, the number of antennas of Cell#0, Cell#1, and Cell#2 may be the same or different.

Application example 2

The difference from the previous application example is that the primary serving cell Cell#0 is selected as the service data transmission point. As shown in FIG. 6, the selected optimal transmission point is Cell#0 and Cell#1, and the primary serving cell Cell#0. Transmitted to the terminal control channel, Cell#l maps the DM-RS according to the DM-RS logical port information sent by Cell#0, and Cell#1 transmits the TBI modulation and coding scheme according to Cell#0, The terminal CRNTI performs modulation and coding scrambling frequency domain compensation mapping on the TBI. For the TBI precoded data, the frequency domain compensated data is S* ^eJ2 , the primary serving cell Cell#0 transmits TB2, and the TB2 is precoded. The data, because transmitted by the primary serving cell, does not require frequency domain compensation.

Application example 3

The difference from the application example 1 is that: the primary serving cell Cell#0 and Cell#1, Cell#2 are all selected as the service data transmission point, and as shown in FIG. 7, the primary serving cell Cell#0 is transmitted to the terminal control channel, the main The serving cell Cell#0 and Cell#1 transmit the data of the TBI, and the data after the TBI is precoded in the primary serving cell does not need to perform frequency domain compensation; for the TBI precoded data transmitted by Cell#1, after frequency domain compensation The data is S ^ ² "\ Cell #2 for transmitting TB2 data. For TB2 precoded data, the frequency domain compensated data is ^s w .

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. Embodiments of the invention are not limited to any specific form of combination of hardware and software.

It is a matter of course that the invention may be embodied in various other forms and modifications without departing from the spirit and scope of the invention.

Industrial applicability

The foregoing technical solution can implement coordinated transmission to the user terminal under the complicated channel condition of the cell edge, improve the data transmission rate of the cell edge user, and can determine the optimal coordinated cell by simple feedback of the user terminal, and calculate and transmit the data to The CQI of each data stream of the user terminal. In addition, the user terminal measures the delay of each measurement cell and feeds back to the base station to enable different cooperation. The cell can perform frequency domain compensation according to the delay, which can effectively overcome the adverse effects caused by different delays of each coordinated cell, and improve the performance of the d and the edge of the zone participating in the coordinated user.

Claims

Claim

1. A multipoint coordinated transmission method, comprising:

2. The method of claim 1 wherein:

The step of the terminal device performing measurement includes:

The terminal device measures the following: the power of the neighboring cell leaking to the terminal, the power of the serving cell to the terminal, and the sum of the interference power and the noise power outside the measured cell set;

The step of the terminal device transmitting the measurement result to the base station includes:

Sending, by the terminal device, the sum to the base station as a measurement result; or sending, by the terminal device, a measurement result to the base station, ' ^Ν

3. The method of claim 2, further comprising:

The content measured by the terminal device further includes: a delay of each measurement cell to the serving cell of the terminal, where the terminal device sends the delay to the base station;

4. The method of claim 3, wherein:

After measuring the delay of each neighboring cell to the serving cell of the terminal, the terminal device sends the time-quantized value to the base station.

5. The method of claim 3, wherein:

The step of compensating the service data in the frequency domain comprises: multiplying the service data to be transmitted by ( ^πω , where: ω is a compensation factor.

6. The method of claim 2, wherein:

The step of the base station predicting that each measurement cell cooperates with other measurement cells to measure the CQI value of the data stream transmitted by the cell includes:

p P a

CQI = ~ ~ = ^m CQI = ~ ~ = "

P „+N ₀ «„+1 , P _m +N ₀ +1 , where CQI of the data stream transmitted by the cell m in the case where the measurement cell m cooperates with the measurement cell n, ^C2 " indicates that the cell m cooperates with the measurement cell n The CQI of the data stream transmitted by the cell n is measured.

7. The method of claim 6 wherein:

The base station calculates the CQI corresponding to the data stream transmitted by the measurement cell m and the measurement cell n when cooperating with the measurement cell 1 by using the following formula:

Ρι+Ν ₀ a _l+ l , P _m +P _n +N ₀ a _m +a _n +l^ where CQI _mnJ denotes measurement cell ^m , measurement cell "measurement cell m and measurement cell in case of measurement cell Z cooperation" The CQI of the jointly transmitted data stream, e^''TM represents the CQI of the measurement cell TM, the measurement cell" and the measurement cell coordinated measurement of the data stream transmitted by the cell.

8. The method of claim 6 or 7, wherein:

The step of the base station selecting, according to the CQI value of each measurement cell, the measurement cell that jointly sends the service data to the terminal device includes:

9. The method of claim 1 wherein:

When the measured cell that transmits the service data to the terminal device includes the current serving cell, the current serving cell is configured to transmit the control channel of the terminal to the terminal device. The service data, the selected neighboring cell in the measurement cell that sends the service data to the terminal device, is used to transmit the service data of the terminal to the terminal device;

10. The method of claim 9 wherein:

The neighboring cell in the measurement cell in which the current serving cell and the cooperative transmitting the service data to the terminal device use the same or different number of antennas when transmitting data to the terminal device.

11. A multipoint coordinated transmission system, comprising a measurement module, and a coordinated cell selection module, wherein:

The measurement module is located in the terminal device, and the measurement module is configured to: perform measurement and send the measurement result to the coordinated cell selection module;

The coordinated cell selection module is located at the base station, and the coordinated cell selection module is configured to: according to the measurement result sent by the terminal, predict, by each measurement cell, the channel quality of the data stream transmitted by the measurement cell when cooperating with other measurement cells Instructing (CQI) value, selecting a measurement cell that cooperatively transmits service data to the terminal device according to a CQI value of each measurement cell.

12. The system of claim 11 wherein:

The measurement module is configured to measure the following: the power leaked by the neighboring cell to the terminal, the power of the serving cell to the terminal, and the sum of the interference power and the noise power outside the measured cell set; the measurement module is set to发送 Send the measurement results to the collaborative cell selection module in the following manner:

The measurement module will be and ^N. The measurement result is sent to the coordinated cell selection module; or the measurement module sends the measurement result to the coordinated cell selection module, ' ^N o; wherein, the neighboring cell leaks power to the terminal and the serving cell to The power of the terminal, where the measurement is the sum of the interference power and the noise power outside the cell set, and i represents the index of the cell.

13. The system of claim 12, wherein:

The coordinated cell selection module is configured to predict a CQI value of the data stream transmitted by the measurement cell when each measurement cell cooperates with other measurement cells in the following manner:

The coordinated cell selection module calculates, by using the following formula, the CQI corresponding to the data stream respectively transmitted by the two measurement cells when the measurement cell m cooperates with the measurement cell n:

p P a

CQI = ~ ~ = ^m CQI = ~ ~ = "

P„+ N ₀ «„+1 , P _m + N ₀ +1 , where the measurement CQI of the data stream transmitted by the cell m is measured when the measurement cell m cooperates with the measurement cell n, and the ^CQI represents the measurement cell m and the measurement cell. The CQI of the data stream transmitted by the cell n is measured in the case of n cooperation.

14. The system of claim 13 wherein:

The coordinated cell selection module calculates the CQI corresponding to the data stream respectively transmitted by the measurement cell m and the measurement cell n when the measurement cell n cooperates with the measurement cell 1 by using the following formula:

Ρι +Ν ₀ a _{l +} l , P _m +P _n +N ₀ a _m + a _n +l ^ where CQI _mnJ represents measurement cell ^m , measurement cell" and measurement cell Z cooperation measurement cell m and measurement cell "CQI of the jointly transmitted data stream, e^''TM indicates the measured cell TM, the measurement cell" and the measured CQI of the data stream transmitted by the cell in the case of measurement cell cooperation.

15. A terminal device for implementing coordinated multi-point transmission, comprising a measuring unit and a feedback unit, wherein:

16. Apparatus according to claim 15 wherein:

The measuring unit is further configured to measure a delay of each measurement cell to the serving cell of the terminal; the feedback unit is further configured to send the time delay obtained by the measuring unit to the base station.

17. Apparatus according to claim 16 wherein:

The measuring unit is further arranged to quantify the measured time delay.

18. Apparatus according to claim 16 or 17, wherein: The feedback unit is set in the following manner to the measurement result to the base station: the feedback unit to the base station and transmits a measurement result as ^N o; or the feedback unit sends a measurement result to the base station, ^ ^1. ;

19. A base station apparatus for implementing coordinated multi-point transmission, comprising a receiving unit, a calculating unit, and a cooperative cell selecting unit:

20. Apparatus according to claim 19 wherein:

The measurement results received by the receiving unit include:

^{Ρ φ ^Ν,} or ";

The power consumption of each neighboring cell leaking to the terminal and the power of the service cell to the local terminal, where the measured is the sum of the interference power and the noise power outside the cell set; the 'W. ; i represents the index of the cell.

21. Apparatus according to claim 20 wherein:

The computing unit is configured to predict, in the following manner, the CQI value of the data stream transmitted by the measurement cell when each measurement cell cooperates with other measurement cells:

The calculating unit calculates, by using the following formula, the CQI corresponding to the data stream respectively transmitted by the two measurement cells when the measurement cell m cooperates with the measurement cell n:

a p a P a

COI = ^m - COI = ~ ^ ~ = - " Pn + N ₀ α„+1 , ― P _m + N ₀ " _m +l, where ^c 2^« denotes the measurement cell When the m cooperates with the measurement cell n, the ^CQI of the data stream transmitted by the cell m is measured, and ^CQI indicates that the measurement cell m and the measurement cell n cooperate to measure the CQI of the data stream transmitted by the cell n.

22. Apparatus according to claim 21 wherein:

The calculating unit uses the following formula to calculate the CQI corresponding to the data stream that the measurement cell m and the measurement cell n respectively transmit when cooperating with the measurement cell 1:

_m + a _n + l _? wherein CQI _m "! represents the CQI of the data stream jointly transmitted by the measurement cell ^m , the measurement cell and the measurement cell Z and the measurement cell Z, and the e^''TM represents the measurement The cell TM, the measurement cell, and the measurement cell cooperate to measure the CQI of the data stream transmitted by the cell.

23. Apparatus according to any of claims 19-22, wherein:

The receiving unit is further configured to receive a delay of each measurement cell to the serving cell of the terminal; the device further includes a compensation factor determining unit: the compensation factor determining unit is configured to: determine, in the coordinated cell selecting unit, a collaboration direction After the measurement device that the terminal device sends the service data, obtains a compensation factor corresponding to the delay of each neighboring cell in the measurement cell that sends the service data to the terminal device, where the compensation factor is used for each collaboration to send the service to the terminal device. The measurement cell of the data compensates the service data in the frequency domain when transmitting the service data to the terminal.

24. Apparatus according to claim 21 or 22, wherein:

The coordinated cell selection unit is configured to: select, according to the CQI value of each measurement cell, a measurement cell that cooperatively sends service data to the terminal device in the following manner: according to the calculated CQI value, select an optimal group of CQI values corresponding to The measurement cell serves as a measurement cell that cooperates to transmit service data to the terminal device.