WO2009026741A1 - Method and device for distributed precoding - Google Patents

Abstract

A method is used for precoding a coded signal in wireless relay network. Firstly, the network device obtains the corresponding information of channel between a plurality of source devices which are combined for relay and a destination device, according to the corresponding information of channel and based on the predetermined rule, determines the precoding coefficient of each coded symbol of the coded signals for a plurality of transmitting antennae, and informs the corresponding precoding coefficient to the corresponding source device. The plurality of source devices perform weighting processing based on transmitting antenna for the corresponding coded symbol of the coded signals using the precoding coefficient, to generate the weighted coded signals to be transmitted, and transmit them through the plurality of transmitting antennae respectively. Since the distributed precoding is introduced on the basis of the distributed coded signals, the space diversity is utilized sufficiently, and according to the dynamical transmission characteristic of channel, the precoding coefficient is adjusted dynamically, so that the signal noise ratio of received signal is maximum, and the data transmission efficiency in multi-step relay network is increased.

Description

 Method and apparatus for distributed precoding

 The present invention relates to a wireless communication relay network, and more particularly to a method and apparatus for relay precoding of distributed coded signals in a relay station, a base station, and a mobile station of a wireless communication relay network. Background technique

 Currently, in wireless multi-hop relay networks, the best solution for joint relay is the Distributed Space Time Block Code (STBC), because distributed space-time block codes do not need to be moved. The station makes any changes, and the physical layer of the base station does not need to be adjusted.

 However, the existing distributed space-time block code scheme is not mature enough, and the antenna selection is still not optimized enough, and the performance is not optimal. Even with the simplest antenna selection, existing distributed space-time block code schemes cannot automatically switch from distributed space-time block codes to local space-time block codes, or automatically switch from local space-time block codes to distributed Space time block code.

 In some cases, distributed space-time block codes may be optimal. However, due to the imbalance of path loss and received power due to the difference in channel transmission coefficients, in some cases, the distributed space-time block code does not provide better performance than the local space-time block code. Therefore, Joint relay, fixed use of distributed space-time block code is unreasonable.

 In addition, taking the most widely used Alamouti code in a wireless communication system as an example, a space-time block code based on an Alamouti code uses a dual-band transmit antenna, and each transmit antenna is located in one relay station, which means that at most two relay stations participate. Joint relaying to obtain spatial diversity gain, but in fact, in order to obtain higher diversity gain, it is hoped that more relay stations can participate in joint relay. Summary of the invention

Aiming at the disadvantages of joint space-based block code based joint relay in the existing wireless multi-hop relay station network, the present invention proposes a technical solution for precoding the encoded signal. First, The network device obtains channel corresponding information between the plurality of source devices to the target device by the joint relay, based on the corresponding information of the channel and based on the signal to noise ratio maximization criterion of the received signal of the target device, and before and after the precoding operation in the plurality of source devices And a criterion for maintaining a total transmit power of each of the coded symbols in the coded signal, determining a precoding coefficient of each of the coded symbols in the plurality of transmit antennas, and notifying the corresponding source device of the corresponding precoding coefficients. The source device performs a weighting process based on the transmit antenna on the corresponding coded symbols in the encoded signal by using the precoding coefficients to generate a weighted coded signal to be transmitted, and respectively transmits the signals through multiple transmit antennas. The coded signal here includes a space time coded signal or a space frequency coded signal.

 According to a first aspect of the present invention, a method for controlling distributed precoding of coded signals to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network is provided, wherein Each of the source devices includes one or more transmit antennas, and the target device includes one or more receive antennas, wherein the method includes the following steps: a. acquiring multiple roots of the multiple source devices Transmitting antenna to channel corresponding information of a plurality of channels between one or more receiving antennas of said target device; b. determining said encoded signal for a corresponding source device based on said channel corresponding information and based on a predetermined rule a precoding coefficient on each of the one or more transmit antennas of each of the coded symbols; c. providing a precoding coefficient for each of the coded symbols on the one or more transmit antennas for the respective source device And for performing distributed precoding on the encoded signal.

 According to a second aspect of the present invention, a method for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network is provided And the method includes the following steps: i. acquiring precoding coefficients of each of the encoded symbols on one or more transmit antennas of the source device; ii. using the precoding coefficient pairs The coded symbols are subjected to transmit antenna based precoding processing to generate precoded coded signals to be transmitted, which are respectively transmitted via one or more transmit antennas.

According to a third aspect of the present invention, a pre-coded control code apparatus for controlling distributed precoding of coded signals to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network is provided Each of the source devices includes one or more transmit antennas, and the target device includes one or more receive antennas, where The precoding control device includes a first obtaining device, a determining device, and a providing device. The first obtaining device is configured to acquire channel corresponding information of multiple channels between multiple transmit antennas of the multiple source devices to one or more transmit antennas of the target device; Determining channel corresponding information, and determining, according to a predetermined rule, a precoding coefficient of each coded symbol on the one or more transmit antennas of the coded signal for the corresponding source device; providing means for the corresponding source device Precoding coefficients for each of the encoded symbols on one or more of the transmit antennas are provided for distributed precoding of the encoded signals.

 According to a fourth aspect of the present invention, there is provided a precoding apparatus for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network And characterized in that the precoding apparatus comprises a second obtaining means and a precoding processing means. The second obtaining means is configured to acquire precoding coefficients of each of the encoded symbols on one or more transmitting antennas of the source device; the precoding processing device is configured to use the precoding coefficient to correspond to the corresponding The coded symbols are subjected to transmit antenna based precoding processing to generate precoded coded signals to be transmitted, which are respectively transmitted via one or more transmit antennas.

 The invention adopts distributed precoding on the basis of the distributed coded signal, fully utilizes spatial diversity, and dynamically adjusts the precoding coefficient according to the dynamic transmission characteristic of the channel, so that the signal to noise ratio of the received signal is maximized. Improve the efficiency of data transmission in multi-hop relay networks. DRAWINGS

 Other features, objects, and advantages of the present invention will become apparent from the Detailed Description of Description In the drawings, identical and similar reference numerals indicate the same or similar device or method steps.

 1 is a schematic diagram of downlink data transmission of a wireless relay network according to an embodiment of the present invention;

2 is a schematic diagram of data transmission of a downlink between two relay stations and a mobile station in FIG. 1; 3 is a schematic diagram of uplink data transmission of a wireless relay network according to an embodiment of the present invention;

 4 is a schematic diagram showing the topology of a multi-hop wireless relay network according to an embodiment of the present invention;

 5 is a flowchart of distributed precoding for controlling a coded signal to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network according to an embodiment of the present invention;

 6 is a flow chart for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network according to an embodiment of the present invention;

 7 is a structure of a precoding control apparatus 10 for controlling distributed precoding of coded signals to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network according to an embodiment of the present invention. Block diagram

 8 is a diagram of a precoding apparatus 20 for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network, in accordance with an embodiment of the present invention. Structure diagram. detailed description

 1 shows a schematic diagram of downlink data transmission of a wireless relay network in accordance with an embodiment of the present invention. Figure 1 includes a base station 1, a relay station 2, a relay station 2, and a mobile station 3. The distributed precoding process in the joint relay of the present invention will be described in detail below by taking the downlink data transmission shown in Fig. 1 as an example.

 First, the base station 1 transmits a signal transmitted to the mobile station 3 to the relay station 2 and the relay station 2, and after receiving the signal transmitted from the base station to the mobile station 3, the base station 1 performs space-time coding on the signal to obtain each The space-time code to be transmitted is grouped; then, the transmission of each symbol on each of the transmitting antennas is controlled according to a precoding coefficient obtained in advance, that is, a precoding coefficient of each symbol in each of the transmitting antennas in the space-time block code.

Hereinafter, the relay station 2 and the relay station 2 each have two transmitting antennas, the mobile station 3 has one receiving antenna, and the space time block code uses an Alamouti code as an example. Referring to FIG. 2, each group of Alamouti The process of determining the precoding coefficients of each symbol in the code on each of the transmitting antennas is described in detail.

The relay station 2 and the relay station 2, after receiving the signal ^ and the signal transmitted by the base station, perform Alamouti encoding on the following form:

Set as the precoding coefficient vector of the first line symbol, W ₂ is the precoding coefficient vector of the second line symbol, where =(^' ) , H w ₂₂ ) , _Wii , _Wi2 , _W21 , _W22 are respectively ^χ 2 . The precoding coefficient vector on each transmitting antenna, since the relay station 2 and the relay station 2 have four transmitting antennas, Wu, W ₁₂ , W ₂₁ , and W ₂₂ are complex vectors having four elements, each element respectively The precoding coefficient on each transmit antenna of the corresponding symbol, where "*," is the conjugate operation. Using W _n , W ₁₂ to precode the first line of the formula (1), ^X 2 is processed in the first At a time, the second line symbol ^-x ; is precoded by W ₂₁ and W ₂₂ , and then transmitted on each of the transmitting antennas at the second moment.

The signal transmitted by the receiving station of the mobile station 3 by the relay station 2 and the relay station 2 at the first moment can be written as follows:

The signal transmitted by the receiving station of the mobile station 3 by the relay station 2 and the relay station 2 at the second moment can be written as follows:

among them, ! ^, h ₂ , h ₃ and h ₄ are the channel transmission coefficients of the four channels of the four transmitting antennas of the relay station 2 and the relay station 2 to one receiving antenna of the mobile station 2, respectively, and the noise received by n1 and n2 respectively. Let it be additive white Gaussian noise.

, 于是，公式（2)和（3)可以被重写为公式（4)It is assumed that the channel is quasi-static, that is, the channel transmission coefficient remains unchanged at the first moment and the second moment (this is a basic premise common to the existing space-time block code), so that ^{w =} ( ^w i W , the first moment) And the channel transmission matrix at the second moment can be expressed as

, then, equations (2) and (3) can be rewritten as formula (4)

H, W _N

 (4)

2J, H ₂ W ₂₁ H, W,

Considering that the receiver of the mobile station 3 is not affected by the precoding, the signal ^T ) is identifiable to the mobile station 3. Therefore, the precoded equivalent channel transmission matrix must have the same form as the uncoded channel transmission matrix. Equation (5) is the expression of the signal received by the mobile station 3 when the joint relay uses the antenna A1 in the relay station 2 and the antenna A3 in the relay station 2 to transmit the distributed space-time code when the pre-coding is not performed:

, 2j

 Equation (6) is obtained according to the formula (5) and the constraint that the transmission power of each symbol before and after precoding is constant.

|Η ν _{11 :} = -(H ₂ W ₂₂ )*

， IH ₂ W ₂₁

,

II w„ ||= 1, l|W ₁₂ ||=1, (6)

2 ₁ 1|= 1, ₂₂ IN l

 According to the formula (6), an optimal precoding coefficient design scheme can be obtained, and the formula (7) gives a formula for solving the precoding coefficient when the signal to noise ratio of the received signal in the mobile station 3 is the largest. Since the noise is assumed to be additive white Gaussian noise, the noise power is constant.

Max(| Η,λΥ, +IH,W ₁₂ n

H _x W _n ^-(U ₂ W ₂₂ )

St H ₂ W ₂₁ =(H,W ₁₂ )*

II W _N ||=1, W] ₂ 1|= 1,

II W, =1, liw ₂₂ ||=i (7) According to formula ( 7 ), the optimal joint time-based block code based on space-time block code can be solved, including local space-time block code and distributed space-time grouping. code.

 1 0 0 0 1 0 0

W, = _w _o , according to formula ( 2 ) and formula ( 3 ), ¹ ~ 0 0 0 1 and 2 - L. Q i indicates a distributed space time block code, and

Indicated is a local space time block code. List all possible distributed and local spacetimes a precoding coefficient vector corresponding to the block code, and constituting a set (8) according to the following method for maximizing the signal to noise ratio of the signal received by the receiver, combined with the channel transmission coefficient, a distributed precoding method for the joint relay The selection is made, that is, the optimal precoding coefficient vector is selected from the Q _w in the set.

Maxd H^ r + | H,W ₁₂ | ² )

^Wei2 w ( 8 ) If the amplitude value of the channel transmission coefficient is only known when determining the precoding coefficient, the phase of the visible channel transmission coefficient is zero, and can also be distributed in space-time coding and local according to formula (8). The optimal selection is made in space-time coding, that is, the optimal precoding coefficient vector is selected from the Q _w in the set.

 As can be seen from the above analysis process, the distributed space time block code can be regarded as a special case of the present invention, and it is obvious that it is not necessarily optimal. Therefore, after distributed precoding (or called joint precoding), joint relay can achieve higher performance.

 The above is a detailed description of the precoding coefficient determining process of the present invention in which the relay station 2 and the relay station 2 respectively have two transmitting antennas and the mobile station 3 has one receiving antenna as an example. For the case where the mobile station 3 has multiple receiving antennas, combining multiple signals received by the plurality of receiving antennas (for example, maximum ratio combining) into one receiving signal can be equivalent to one receiving antenna, and also according to the same. The precoding coefficient process described above determines the precoding coefficients of the respective symbols in the space time block code on the respective transmission lines. For the case where there are more relay stations and more transmitting antennas, the precoding coefficients of the respective symbols in the space time block code on the respective transmission lines are also determined according to the above-described precoding coefficient process.

 Although the present invention has been described above by taking the downlink data transmission of the two-hop wireless relay network shown in Fig. 1, that is, the relay station 2 and the relay station 2, jointly relaying data to the mobile station 3 as an example. It should be understood by those skilled in the art that the present invention is not limited thereto. In the network topology shown in FIG. 1, if the mobile station 3 is within the coverage of the base station 1, the base station 1 can also participate in the joint relay. That is, the base station 1 can jointly relay data to the mobile station 3 together with the relay station 2 or the relay station 2.

It should be noted that the determination of the precoding coefficient may take a centralized determination manner or a distributed determination manner. Specifically, the manner of centralized determination means that: the precoding coefficient is determined by the base station 1 (or the relay station 2 or the relay station 2, or other network equipment), and then the base station 1 (the relay station 2 or the relay station 2, or other network equipment) Relay station 2 and relay station ^{2. The} corresponding precoding coefficients are respectively notified to the relay station 2 and the relay station 2, respectively. The manner of distributed determination means that both the relay station 2 and the relay station 2 acquire the channel transmission coefficients between the relay station 2 and the relay station 2 and the mobile station 3 (obtained from the base station 1, or acquired from the mobile station 3, or the relay station 2) And the relay station 2, mutually notifying each other of the channel transmission coefficient between it and the mobile station 3), and then calculating the precoding coefficients, respectively.

 In actual use, the base station 1 usually determines the precoding coefficient and notifies the relay station 2 and the relay station 2 in consideration of the simplicity and cost of the relay station. In view of the instability of the radio channel, the base station 1 can determine the precoding coefficients periodically or non-periodically, and inform the relay station 2 and the relay station 2 so that the signals received by the mobile station 3 are always optimal.

 Specifically, the precoding coefficient may be determined by the base station 1 according to the channel transmission coefficient between the relay station 2 and the relay station 2, and the mobile station 3, or the precoding coefficient may be determined by a dedicated network device; of course, the relay station 2 or the relay station may also be used. 2, to determine. In actual use, the precoding coefficient is usually determined by the base station 1 in consideration of the simplicity and cost of the relay station.

 Specifically, the downlink channel transmission coefficient between the relay station 2 and the relay station 2 and the mobile station 3 can be measured by the mobile station 3, and fed back to the base station 1 via the relay station 2 and the relay station 2. For the time division duplex system, the channel transmission coefficients of the uplink channel and the downlink channel are approximately the same, and the uplink channel transmission coefficients between the uplink channel and the mobile station 3 can also be measured by the relay station 2 and the relay station 2, and fed back to the base station 1.

 For uplink data transmission, the relay station 2 and the relay station 2 jointly relay data to the base station 1. Preferably, if the mobile station 3 supports the function of joint relay, the mobile station 3 can also participate in joint relay, as shown in FIG. Show.

 As described above, in the uplink data transmission, the determination of the precoding coefficient can be determined in a centralized manner, or a distributed determination manner can be adopted. For example, the precoding coefficient may be determined by the base station 1 according to the channel transmission coefficient between the relay station 2 and the relay station 2, and the base station 1, or the precoding coefficient may be determined by a dedicated network device; of course, the relay station 2 and the relay station 2 may also be used. To determine their respective precoding coefficients. The precoding coefficient can also be determined by the mobile station 3 if the mobile station 3 participates in the joint relay.

In actual use, the precoding coefficients are usually determined by the base station 1 in consideration of the simplicity and cost of the relay station and the mobile station. Considering the instability of the radio channel, the base station 1 can determine the precoding coefficients periodically or non-periodically, and notifies the relay station 2 and the relay station 2, so that The signal received by base station 1 is always optimal.

 Specifically, the uplink channel transmission coefficients between the relay station 2 and the relay station 2 and the base station 1 can be measured by the base station 1. For the time division duplex system, the channel transmission coefficients of the uplink channel and the downlink channel are approximately the same, and the downlink channel transmission coefficients between the uplink channel and the base station 1 can also be measured by the relay station 2 and the relay station 2, and fed back to the base station 1.

 It will be understood by those skilled in the art that the present invention is not limited to the two-hop wireless relay network shown in FIG. 1 and FIG. 3, and is applicable to a three-hop or more-hop wireless relay network, for example, as shown in FIG. Jump wireless relay network.

 In addition, it should be noted that although the present invention has been described above by taking a space time block code as an example, those skilled in the art should understand that the present invention is equally applicable to other space time coded signals according to the teachings of the present application; The present invention is also applicable to a space-frequency coded signal, and the different frequencies of the space-frequency coded signal can be understood as corresponding to different times of space-time coding.

 Figure 5 illustrates a flow diagram for distributed precoding of coded signals to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network in accordance with an embodiment of the present invention.

 In Fig. 1, the relay station 2 and the relay station 2 jointly relay the signals to the mobile station 3, that is, the relay station 2 and the relay station 2, which are source devices, and the mobile station 3 is the target device. The relay station 2 and the relay station 2 respectively have two transmitting antennas, and the mobile station 3 has one receiving antenna; the base station 1 is a network device, that is, the base station 1 is responsible for determining the precoding coefficient, that is, each coded symbol in the encoded signal is in each transmitting antenna. The weighting factor on it. Here, the coded signal includes a space time coded signal or a space frequency coded signal.

 Referring to Fig. 5, and in conjunction with Fig. 1, the base station 1 controls the relay station 2 and the relay station 2, and the process of performing distributed precoding on the coded signals to be jointly relayed to the mobile station 3 will be described in detail.

First, in step S11, the base station 1 acquires channel corresponding information of four channels between one of the four transmit antennas of the relay station 2 and the relay station ² to the mobile station 3. For example, the corresponding information of the channel is a channel transmission coefficient, and the channel corresponding information of the four channels is four channel transmission coefficients. hh ₂ , h ₃ and h4. If the mobile station 3 has M (M is a positive integer) root receiving antenna, then four transmitting antennas of the relay station 2 and the relay station 2 to the mobile station There are 4 XM channel transmission coefficients between the M receiving antennas of 3.

 Specifically, the base station 1 acquires channel coefficients between four receiving antennas of the relay station 2 and the relay station 2 to a receiving antenna between the mobile station 3: one is that after the mobile station 3 performs channel estimation, Transmitted to the base station 1; one is that after the mobile station 3 performs channel estimation, the channel transmission coefficient between the channel and the relay station 2 is transmitted to the relay station 2, and the channel transmission coefficient between the channel and the relay station 2 is transmitted to the relay station 2, The channel transmission coefficients are transmitted to the base station 1 by the relay station 2 and the relay station 2'. For the time division duplex system, the uplink and downlink channel symmetry may also be estimated by the relay station 2 and the relay station 2, respectively, and the channel transmission coefficient with the mobile station 3, and transmitted to the base station 1.

Then, in step S12, the base station 1 determines precoding coefficients of each of the coded symbols on the four transmit antennas based on the acquired channel corresponding information and a predetermined rule. Here, the predetermined rule includes: the precoding coefficient is determined such that the signal to noise ratio of the signal received by the mobile station 3 is the largest and the relay station 2 and the relay station 2 maintain the total transmission power of each coded symbol in the coded signal before and after the medium precoding operation constant. Taking the relay station 2 and the relay station ^{2 as the example} , using the Alamouti code and the channel corresponding information as the channel transmission coefficient, the base station 1 can determine the precoding coefficient of each symbol in each group of Alamouti codes on the four transmitting antennas according to the formula (7). .

 Finally, in step S13, the base station 1 transmits the precoding coefficients of the respective code symbols on the transmit antennas A1 and A2 in the coded signal to the relay station 2, and the precoding coefficients of the respective code symbols in the coded signals on the transmit antennas A3 and A4. It is sent to the relay station 2, for the relay station 2 and the relay station 2, to perform distributed precoding on the encoded signal.

 It should be noted that the process of determining the precoding coefficient of the present invention is described by taking the channel transmission coefficient as an example. Actually, it may also be based only on the amplitude value of the channel transmission coefficient (in this case, the phase of the visible channel transmission coefficient is zero. ) to determine the precoding coefficient.

 In addition, it should be noted that the determination of the precoding coefficients in the foregoing embodiment adopts a centralized determination manner, and the base station 1 collectively determines the precoding of each coded symbol in the encoded signal on the transmitting antennas of the relay station 2 and the relay station 2. The coefficients, of course, the precoding coefficients can also be determined centrally by the relay station 2 or the relay station 2, or the mobile station 3.

Alternatively, the determination of the precoding coefficient may also take a distributed determination manner, for example, The relay station 2 and the relay station 2 respectively acquire channel corresponding information between their four antennas A1, A2, A3 and A4 to the mobile station 3, and then the relay station 2 determines each coded symbol in the encoded signal in its antenna Al according to the channel corresponding information. The precoding coefficient on A2, the relay station 2, determines the precoding coefficient of each coded symbol in the coded signal on its antennas A3, A4 according to the channel corresponding information.

 The base station 1 can also participate in the joint relay, that is, the base station 1 can jointly relay the signal to the mobile station 3 together with the relay station 2 or the relay station 2; or the base station 1 and the relay station 2 and the relay station 2 jointly relay the signal to the mobile station 3, At this time, the process of determining the distributed precoding coefficient is the same as above, and a centralized determination manner or a distributed determination manner may be adopted.

 6 shows a flow diagram for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network, in accordance with an embodiment of the present invention.

 It is assumed that in Fig. 1, the relay station 2 and the relay station 2 jointly relay the signals to the mobile station 3, that is, the relay station 2 and the relay station 2, which are source devices, and the mobile station 3 is the target device. The relay station 2 and the relay station 2 respectively have two transmitting antennas, and the mobile station 3 has one receiving antenna; the base station 1 is a network device, that is, the base station 1 is responsible for determining the precoding coefficient, that is, each coded symbol in the encoded signal is in each transmitting antenna. Precoding coefficient on. Here, the coded signal includes a space time coded signal or a space frequency coded signal.

 The flow of precoding the coded signals to be relayed to the mobile station 3 with the relay station 2 in the relay station 2 will be described in detail below with reference to Fig. 6, in conjunction with Fig. 1.

 First, in step S21, the relay station 2 acquires precoding coefficients on the two transmitting antennas of the relay station 2 of each of the coded signals to be jointly relayed to the mobile station 3 with the relay station 2.

 Specifically, there are two ways in which the relay station 2 acquires precoding coefficients. The first way is to get it from other network devices. For example, if the precoding coefficient is determined by the base station 1 or the relay station 2, or the mobile station 3, the relay station 2 obtains the above precoding coefficients from the base station 1 or the relay station 2, or the mobile station 3.

The second way is that the relay station 2 itself determines the above precoding coefficients. Specifically, the relay station 2 acquires one of the four transmitting antennas of the relay station 2 and the relay station 2 to the mobile station 3. The channel corresponding information of the four channels between the antennas is received, and the precoding coefficients are determined according to the corresponding information of the channel and a predetermined rule.

 Specifically, there are various ways in which the relay station 2 acquires channel corresponding information between the four transmitting antennas of the relay station 2 and the relay station 2 to one receiving antenna of the mobile station 3. The first method is that the mobile station 3 performs channel estimation to obtain channel corresponding information between the relay station 2 and the relay station 2, and then transmits the information to the relay station 2. The second way is: after the mobile station 3 performs channel estimation, the channel information between the mobile station 3 and the relay station 2 is transmitted to the relay station 2, and the channel information between the mobile station 3 and the relay station 2 is transmitted to the relay station 2, and then the relay station 2 And the relay station 2 transmits the channel corresponding information to the base station 1. Then, the base station 1 transmits the channel corresponding information between the relay station 2 and the mobile station 3 to the relay station 2, and transmits the channel corresponding information between the relay station 2 and the mobile station 3 to the relay station 2.

 Further, for the time division duplex system, the uplink and downlink channels are symmetric, and the relay station 2 and the relay station 2 can also estimate the channel corresponding information between them and the mobile station 3, respectively, and transmit them to the base station 1. Then, the base station 1 transmits the channel corresponding information between the relay station 2 and the mobile station 3 to the relay station 2, and transmits the channel corresponding information between the relay station 2 and the mobile station 3 to the relay station.

 If the precoding coefficients are in a centralized determination manner, the relay station 2 also determines the precoding coefficients of the respective code symbols in the coded signals on the two transmitting antennas of the relay station 2, and supplies them to the relay station 2.

 Then, in step S22, the relay station 2 performs a pre-coding process based on the transmit antenna on the corresponding coded symbols in the coded signal by using the pre-coding coefficients to generate a pre-coded coded signal to be transmitted, which is respectively performed via two transmit antennas. send.

当然， 中继站 2与中继站 2，一起联合中继信号至移动站 3是本领 域的技术人员应知晓的常识， 本发明这里不再赘述。 Taking the symbol ^x d to be transmitted in the first line of the formula (1), it is assumed that the precoding coefficients of the symbol ^χ ι, determined according to the formula (7) on the quadruple transmitting antenna of the relay station 2 and the relay station 2 are respectively Wn - G^, 1/2, 1/2, 1/2) ^T , Wi ₂ = , 0, 0, , After weighting, the signals to be transmitted on the antennas A1 and Α2 of the relay station 2 are: 1 ₁ The signals to be transmitted on antennas A3 and Α4 of relay station 2 are:

Of course, the relay station 2 and the relay station 2, together with the relay signal to the mobile station 3, are common knowledge that those skilled in the art should know, and the present invention will not be repeated here.

 Preferably, the relay station 2 also acquires channel corresponding information of two channels between its two transmitting antennas to one receiving antenna of the mobile station 3, and transmits the channel corresponding information to the base station 1. Here, the channel corresponding information includes a channel transmission coefficient or an amplitude value of a channel transmission coefficient.

 Specifically, the manner in which the relay station 2 acquires the channel corresponding information is as follows: The relay station 2 receives the channel corresponding information estimated by the mobile station 3 transmitted by the mobile station 3, and transmits it to the base station 1. For the time division duplex system, in the case where the uplink and downlink channels are symmetrical, the relay station 2 can also estimate the channel corresponding information of the mobile station 3 to its two transmitting antennas, and send it to the base station 1.

 In the above, a specific embodiment of the present invention has been described in detail by taking the source device as the relay station 2 and the relay station 2, and the target device as the mobile station 3. It should be noted that the present invention is not limited thereto, and multiple source devices and target devices have multiple combinations: multiple source devices include multiple relay stations, target devices include relay stations or mobile stations or base stations; multiple source devices include one base station. And one or more relay stations, the target device includes a relay station or a mobile station; the plurality of source devices include one mobile station and one or more relay stations, and the target device includes a relay station or a base station. For example, Figure 4 shows a schematic diagram of a network topology in which the source device is two or three relay stations and the target device is a relay station.

7 illustrates a precoding control apparatus 10 for controlling distributed precoding of coded signals to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network according to an embodiment of the present invention. Block diagram of the structure. The precoding control device 10 includes a first obtaining device 11, a determining device 12, and a providing device 13. Preferably, the first obtaining device 11 further comprises a first receiving device 111. Those skilled in the art in accordance with the teachings herein, should understand that only the first obtaining means 11 wherein the determining means providing means 13 and I ² is the apparatus necessary for the present invention embodiment, a first receiving means 111 is optional device.

It is assumed that in FIG. 1, the relay station 2 and the relay station 2 jointly relay signals to the mobile station ³ , that is, the relay station 2 and the relay station 2, which are source devices, and the mobile station 3 is a target device. The relay station 2 and the relay station 2 respectively have two transmitting antennas, and the mobile station 3 has one receiving antenna; the base station 1 is a network device, that is, the base station 1 is responsible for determining the precoding coefficient, that is, each coded symbol in the encoded signal is transmitted every time. The weighting factor on the antenna. The coded signal here includes a space time coded signal Or a space frequency coded signal.

The process of performing distributed precoding of the coded signals to be jointly relayed to the mobile station 3 will be described in detail below with reference to FIG. ⁷ in conjunction with FIG. 1 for the precoding control apparatus 10 in the base station 1 to control the relay station 2 and the relay station 2.

First, the first acquisition means 11 acquires channel corresponding information of four channels between one of the four transmitting antennas of the relay station 2 and the relay station 2 to the one of the receiving stations. For example, the channel corresponding information is a channel transmission coefficient, and the channel corresponding information of the four channels is four channel transmission coefficients, h ₂ , h _{3 ,} and h ₄ . If the mobile station 3 has M (M is a positive integer) root receiving antenna, there are 4 XM channel transmission coefficients between the four transmitting antennas of the relay station 2 and the relay station 2, and the M receiving antennas of the mobile station 3.

 Specifically, the first obtaining means 11 acquires channel coefficients between the four transmitting antennas of the relay station 2 and the relay station 2 to a receiving antenna between the mobile station 3 in a plurality of ways: One is that the mobile station 3 performs channel After estimation, it is sent to the first acquisition device 11; one is the channel transmission coefficient between the channel transmission coefficient between the mobile station 3 and the relay station 2, and the channel transmission coefficient between the mobile station 3 and the relay station 2, and the relay station 2 It is transmitted to the relay station 2, and the relay station 2 and the relay station 2 transmit the channel transmission coefficients to the first acquisition means 11. For the time division duplex system, the uplink and downlink channels are symmetric, and the channel transmission coefficients between the mobile station 3 and the relay station 2 can be estimated by the relay station 2 and the relay station 2, respectively, and sent to the first acquisition device 11.

Then, the determining means 12 determines the precoding coefficients of each of the encoded symbols on the four transmitting antennas based on the acquired channel corresponding information and a predetermined rule. Here, the predetermined rule includes: the precoding coefficient is determined such that the signal to noise ratio of the signal received by the mobile station 3 is the largest and the relay station 2 and the relay station 2 maintain the total transmission power of each coded symbol in the coded signal before and after the medium precoding operation constant. Taking the relay station 2 and the relay station 2, using the Alamouti code and the corresponding information of the channel as the channel transmission coefficient, the base station 1 can provide each of the code symbols in the device coded signal according to the formula (7): "on the transmitting antennas A1 and A2. The precoding coefficient on the transmitting relay station 2 transmits the precoding coefficients of the respective encoded symbols in the encoded signal on the transmitting antennas A3 and A4 to the relay station 2 for relaying Station 2 and relay station 2 perform distributed precoding on the encoded signal.

 It should be noted that the process of determining the precoding coefficient of the present invention is described by taking the channel transmission coefficient as an example. Actually, it may also be based only on the amplitude value of the channel transmission coefficient (in this case, the phase of the visible channel transmission coefficient is zero. ) to determine the precoding coefficient.

 In addition, it should be noted that the determination of the precoding coefficients in the foregoing embodiment adopts a centralized determination manner, and the base station 1 collectively determines the precoding of each coded symbol in the encoded signal on the transmitting antennas of the relay station 2 and the relay station 2. The coefficients, of course, the precoding coefficients can also be determined centrally by the relay station 2 or the relay station 2, or the mobile station 3.

 Alternatively, the determination of the precoding coefficient may also take a distributed determination manner, for example, the relay station 2 and the relay station 2 respectively acquire the channel correspondence between their quadruple antennas A1, A2, A3 and A4 to the mobile station 3. Information, then the relay station 2 determines the precoding coefficients of each of the encoded symbols on its antennas A1, A2 according to the channel corresponding information, and the relay station 2 determines, according to the channel corresponding information, each coded symbol in the encoded signal at its antennas A3, A4 Precoding coefficient on.

 The base station 1 can also participate in the joint relay, that is, the base station 1 can jointly relay the signal to the mobile station 3 together with the relay station 2 or the relay station 2; or the base station 1 and the relay station 2 and the relay station 2 jointly transmit the relay signal to the mobile station 3, At this time, the process of determining the distributed precoding coefficient is the same as above, and a centralized determination manner or a distributed determination manner may be adopted.

8 illustrates a precoding apparatus for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network, in accordance with an embodiment of the present invention. 20 structural block diagram. The precoding apparatus 20 includes a second obtaining means 21, a precoding processing means 22, a third obtaining means ^23, and a second transmitting means 24. For the sake of brevity, the optional sub-devices of many preferred embodiments are shown in FIG. 8, and those skilled in the art will understand from the teachings of the present application that only the second obtaining means 21 and the pre-encoding processing means 22 are understood. It is a device necessary for the implementation of the invention, and other sub-devices are optional devices.

It is assumed that in FIG. 1, the relay station 2 and the relay station 2 jointly relay signals to the mobile station 3, that is, the relay station 2 and the relay station 2, which are source devices, and the mobile station 3 is a target device. The relay station 2 and the relay station 2 respectively have two transmitting antennas, and the mobile station 3 has one receiving antenna; 2007/002594

1 is a network device, that is, the base station 1 is responsible for determining the precoding coefficient, that is, the precoding coefficient of each coded symbol in the encoded signal on each of the transmitting antennas. Here, the coded signal includes a space time coded signal or a space frequency coded signal.

 The process of precoding the coded signals to be jointly relayed to the mobile station 3 with the relay station 2 by the precoding apparatus 20 in the relay station 2 will be described in detail below with reference to FIG.

 First, the second obtaining means 21 acquires a precoding coefficient with respect to the two transmitting antennas of the relay station 2 of each of the coded signals to be jointly relayed to the mobile station 3 with the relay station 2.

 Specifically, the second obtaining means 21 obtains two types of precoding coefficients in two ways. The first way is that the second obtaining means 21 acquires from other network devices. For example, if the precoding coefficient is determined by the base station 1 or the relay station 2, or the mobile station 3, the relay station 2 acquires the above precoding coefficients from the base station 1 or the relay station 2' or the mobile station 3.

 The second way is that the second obtaining means 21 itself determines the above-described precoding coefficient. Specifically, the second obtaining means 21 acquires channel corresponding information of four channels between four receiving antennas of the relay station 2 and the relay station 2, and a receiving antenna between the mobile station 3, and according to the channel corresponding information and reservation Rule, determine the above precoding coefficient.

Specifically, the second obtaining means 21 acquires a plurality of ways of channel corresponding information between the four transmitting antennas of the relay station 2 and the relay station 2 to one receiving antenna of the mobile station 3. The first way is that the mobile station 3 performs channel estimation to obtain channel corresponding information between the relay station ² and the relay station T, and then transmits the information to the second acquisition device 21. The second way is: after the mobile station 3 performs channel estimation, the channel information between the mobile station 3 and the relay station 2 is sent to the second acquiring device 21, and the channel information between the mobile station 3 and the relay station 2 is transmitted to the relay station 2, and the relay station 2. The channel corresponding information between the mobile station 3 and the mobile station 3 is transmitted to the base station 1. Then, the base station 1 transmits the channel corresponding information between the relay station 2 and the mobile station 3 to the second acquisition means 21.

Further, for the time division duplex system, the uplink and downlink channels are symmetrical, and the second acquisition means 21 can also estimate the channel corresponding information between the relay station 2 and the mobile station 3. The relay station 2 estimates the channel corresponding information between it and the mobile station 3 and transmits it to the base station 1. Then, the base station 1 will The relay station 2, the channel corresponding information between the mobile station 3 and the mobile station 3 is sent to the second obtaining means 21. If the precoding coefficient is determined in a centralized manner, the second obtaining means 21 further determines that each of the encoded symbols in the encoded signal is at the relay station 2, The precoding coefficients on the two transmit antennas are provided to the relay station 2, .

 Then, the precoding processing means 22 performs a precoding process based on the transmit antenna on the corresponding coded symbols in the coded signal by using the precoding coefficients to generate a precoded coded signal to be transmitted, which are respectively transmitted via two transmit antennas.

Pre-coding on the equation (1) the symbols ^{χ ι} first row to be transmitted, ^[chi] 2 example, assume that the symbol is determined according to the formula (7), ^χ 2 at the relay station 2 and the relay station 2, the four transmit antennas The coefficients are W _n = (l/2, 1/2, 1/2, 1/2) ^T , Wi ₂ = (― , 0, 0, ) ^τ , then the weighting process, the antenna A1 of the relay station 2, The signals to be transmitted on Α2 are: The signals to be transmitted on antennas A3 and Α4 of relay station 2 are:

 Of course, the relay station 2 and the relay station 2, together with the relay signal to the mobile station 3, are common knowledge that those skilled in the art should know, and the present invention will not be described herein.

 Preferably, the third obtaining means 23 also acquires channel corresponding information of two channels between its two transmitting antennas to one receiving antenna of the mobile station 3, and transmits the channel corresponding information to the base station 1 by the second transmitting means 24. . Here, the channel corresponding information includes a channel transmission coefficient or an amplitude value of a channel transmission coefficient.

 Specifically, the manner in which the third acquisition means 23 acquires the channel corresponding information is as follows: The third acquisition means 23 acquires the channel corresponding information estimated by the mobile station 3 transmitted by the mobile station 3, and transmits it to the base station 1 by the second transmitting means 24. For the time division duplex system, in the case where the uplink and downlink channels are symmetrical, the third obtaining means 24 can also estimate the channel corresponding information of the mobile station 3 to its two transmitting antennas, and transmit it to the base station 1 by the second transmitting means 24.

The specific embodiment of the present invention has been described in detail above by taking the source device as the relay station 2 and the relay station 2, and the target device as the mobile station 3. It should be noted that the present invention is not limited thereto, and multiple source devices and target devices have multiple combinations: multiple source devices include multiple relay stations, target devices include relay stations or mobile stations or base stations; multiple source device packages A base station and one or more relay stations, the target device includes a relay station or a mobile station; the plurality of source devices include one mobile station and one or more relay stations, and the target device includes a relay station or a base station. For example, FIG. 4 shows a schematic diagram of a network topology in which the source device is two or three relay stations and the target device is a relay station.

 The specific embodiments of the present invention have been described above. It is to be understood that the invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the appended claims.

Claims

Claims 1 . A method for controlling distributed precoding of coded signals to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network, wherein each of the source devices includes one or A plurality of transmit antennas, the target device comprising one or more receive antennas, wherein the method comprises the steps of:  Obtaining channel corresponding information of multiple channels between multiple transmit antennas of the plurality of source devices to one or more receive antennas of the target device;  And determining, according to the channel corresponding information, a precoding coefficient of each of the encoded symbols on the one or more transmit antennas of the encoded signal according to a predetermined rule;  c providing, for the respective source device, precoding coefficients for each of the coded symbols on one or more of the transmit antennas for distributed precoding of the coded signals.  2. The method according to claim 1, wherein the step a comprises the following steps:  - receiving the plurality of channel corresponding information transmitted by the target device.  The method according to claim 1 or 2, wherein the step a further comprises the following steps:  - receiving the plurality of channel corresponding information respectively transmitted by the plurality of source devices. The method according to any one of claims 1 to 3, wherein the network device is one of the source network devices, wherein the step b further comprises:  Determining, according to the channel corresponding information, a precoding coefficient for each of the encoded symbols on the one or more transmit antennas of the coded signal based on the predetermined rule;  The step c further includes:  - providing the network device with precoding coefficients for each of the coded symbols on one or more of the transmit antennas for distributed precoding of the coded signals. The method according to any one of claims 1 to 4, characterized in that The predetermined rule includes: the precoding coefficient is determined such that a signal to noise ratio of a transmission signal received by the target device from the plurality of source devices is maximized and the precoding operation is performed before and after the plurality of source devices The total transmit power of each coded symbol in the encoded signal remains unchanged.  The method according to any one of claims 1 to 5, wherein the network device comprises a base station or a relay station or a mobile station,  The plurality of source devices and target devices include any one of the following combinations: - the plurality of source devices includes a plurality of relay stations, and the target devices include a relay station or a mobile station or a base station;  - said plurality of source devices comprising a base station and one or more relay stations, said target device comprising a relay station or a mobile station;  - The plurality of source devices comprise a mobile station and one or more relay stations, the target device comprising a relay station or a base station.  The method according to any one of claims 1 to 6, wherein the encoded signal comprises a space time coded signal or a space frequency coded signal.  8. A method for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network, the method comprising the steps of:  i. acquiring precoding coefficients of each of the encoded symbols on one or more transmit antennas of the source device;  Ii. performing a pre-coding process based on the transmit antenna on the corresponding coded symbols by using the pre-coding coefficients to generate a pre-coded coded signal to be transmitted, which are respectively transmitted via one or more transmit antennas.  9. The method of claim 8 wherein said step i further comprises: precoding coefficients on one or more transmit antennas of the source device. 10. The method according to claim 9, further comprising the steps of: - acquiring one or more transmit antennas of the source device to a channel between one or more receive antennas of the target device Channel corresponding information; - transmitting the channel corresponding information to the network device. ,  The method according to any one of claims 8 to 10, wherein the plurality of source devices and target devices comprise any one of the following combinations:  The plurality of source devices comprising a plurality of relay stations, the target devices comprising relay stations or mobile stations or base stations;  - said plurality of source devices comprising a base station and one or more relay stations, said target device comprising a relay station or a mobile station;  - The plurality of source devices comprise a mobile station and one or more relay stations, the target device comprising a relay station or a base station.  The method according to any one of claims 8 to 11, wherein the coded signal comprises a space time coded signal or a space frequency coded signal.  13. A pre-programmed control code device for controlling distributed precoding of coded signals to be jointly relayed to a target device by a plurality of source devices in a network device of a wireless relay network, wherein each of the source devices The one or more receiving antennas are included, the target device includes one or more receiving antennas, and the precoding control device includes: a first acquiring device, configured to acquire multiple transmissions of the multiple source devices Channel corresponding information of a plurality of channels between the antenna and one or more receiving antennas of the target device; determining means for determining, according to the channel corresponding information, the corresponding source device according to the predetermined rule a precoding coefficient of each of the coded symbols on one or more of the transmit antennas;  And means for providing, for the corresponding source device, precoding coefficients of the each code symbol on the one or more transmit antennas thereof for distributed precoding of the coded signal.  The pre-coding control device according to claim 13, wherein the first obtaining device comprises:  And a first receiving device, configured to receive the multiple channel corresponding information sent by the target device. The pre-coding control device according to claim 13 or 14, wherein the first receiving device is further configured to: - receiving the plurality of channel corresponding information respectively transmitted by the plurality of source devices. The pre-coding control device according to any one of claims 13 to 15, wherein the network device is one of the source network devices, and the determining device is further configured to:  Determining, according to the channel corresponding information, a precoding coefficient for each of the encoded symbols on the one or more transmit antennas of the coded signal based on the predetermined rule;  Wherein, the providing device is further configured to:  - providing the network device with precoding coefficients for each of the coded symbols on one or more of the transmit antennas for distributed precoding of the coded signals.  The precoding control apparatus according to any one of claims 13 to 16, wherein the predetermined rule comprises: the precoding coefficient is determined such that the target device receives the plurality of The signal to noise ratio of the transmission signals of the source devices is the largest and the total transmission power of each of the coded signals in the coded signals before and after the precoding operation in the plurality of source devices remains unchanged.  The precoding control apparatus according to any one of claims 13 to 17, wherein the network device comprises a base station or a relay station or a mobile station,  The plurality of source devices and target devices include any one of the following combinations: - the plurality of source devices includes a plurality of relay stations, and the target devices include a relay station or a mobile station or a base station;  - said plurality of source devices comprising a base station and one or more relay stations, said target device comprising a relay station or a mobile station;  - The plurality of source devices comprise a mobile station and one or more relay stations, the target device comprising a relay station or a base station.  The precoding control apparatus according to any one of claims 13 to 18, wherein the coded signal comprises a space time coded signal or a space frequency coded signal. 20. A precoding apparatus for precoding a coded signal to be jointly relayed to a target device with another one or more source devices in a source device of a wireless relay network, characterized in that the precoding device include: a second obtaining means, configured to acquire a precoding coefficient of each coded symbol in the encoded signal on one or more transmit antennas of the source device;  a precoding processing apparatus, configured to perform, by using the precoding coefficient, a transmit antenna based precoding process on the corresponding coded symbol, to generate a precoded coded signal to be transmitted, and respectively send the signal through one or more transmit antennas .  The pre-encoding device according to claim 20, wherein the second obtaining device is further configured to:  - obtaining precoding coefficients for each of the encoded symbols from a network device on one or more transmit antennas of the source device.  The precoding apparatus according to claim 21, further comprising: third acquiring means, configured to acquire one or more receiving antennas of the source device to the one or more receiving devices of the target device Channel corresponding information of the channel between the antennas;  And a second sending device, configured to send the channel corresponding information to the network device. The precoding apparatus according to any one of claims 20 to 22, wherein the plurality of source devices and target devices comprise any one of the following combinations:  - the plurality of source devices comprise a plurality of relay stations, the target devices comprising relay stations or mobile stations or base stations;  - said plurality of source devices comprising a base station and one or more relay stations, said target device comprising a relay station or a mobile station;  - The plurality of source devices comprise a mobile station and one or more relay stations, the target device comprising a relay station or a base station.  The precoding apparatus according to any one of claims 20 to 23, wherein the coded signal comprises a space time coded signal or a space frequency coded signal.  A network device in a wireless communication network, characterized by comprising the precoding control device according to any one of claims 13 to 19 and/or according to any one of claims 20 to 24. Precoding device.  26. The network device of claim 25, the network device comprising a base station or a relay station or a mobile station.