CN112994764B - Position and transmitting-receiving precoding design method in HAP (Hap-assisted multi-pair) relay communication - Google Patents

Abstract

The invention provides a position and transmitting-receiving precoding design method in HAP auxiliary multi-pair relay communication, and the wireless transmission method mainly comprises the following steps: a user sends an uplink pilot signal to an HAP, and the HAP receives and carries out channel estimation on the uplink pilot signal sent by the user so as to acquire partial channel state information of the user; and the HAP calculates a receiving and transmitting precoding matrix by using the partial channel state information of the user, calculates the position of the HAP based on a maximized system and rate, and amplifies and transmits a signal to be transmitted by a transmitting end user to a target user. The method is simple to operate and practical in fitting, provides wide-range reliable communication for ground users, ensures quick and accurate information transfer between the ground users, and has important practical significance for the mobile relay auxiliary multi-antenna communication system.

Description

Location and Transceiver Precoding Design Method in HAP-assisted Multi-Pair Relay Communication

technical field

The invention belongs to the technical field of wireless communication, and in particular relates to a method for designing position and transceiving precoding in HAP-assisted multi-pair relay communication based on partial CSI.

Background technique

With the rapid development of wireless communication technology, the high altitude platform (HAP) communication system has received extensive attention in recent years and is an emerging wireless communication system. The HAP communication system mainly refers to a system that provides communication services for ground users by using HAP with a certain payload and an antenna, similar to a low-orbit satellite communication system. However, compared with low-orbit satellites, HAP has the advantages of fast movement, strong maneuverability and low implementation cost. It can move to potential ground users at any time, and better adapt to the communication environment through real-time dynamic adjustment, thereby effectively enhancing Local area communication quality. Therefore, HAP can still provide basic communication services even in the event of major natural disasters or in remote geographical areas.

In the mobile communication system, as a mobile relay, it is an important function of HAP to improve the connectivity of terrestrial wireless equipment, expand the network coverage, and ensure the communication quality of terrestrial users. However, when multiple pairs of users access, the HAP acts as a relay while amplifying and forwarding signals, and at the same time, it will cause certain interference to non-target users and reduce the communication quality of users. In order to ensure the transmission quality of the signal and improve the system performance, it is indeed necessary to propose a design method of position and transceiver precoding in HAP-assisted multi-pair relay communication to solve the above problems.

SUMMARY OF THE INVENTION

Purpose of the invention: The present invention proposes to provide a method for designing position and transceiving precoding in HAP-assisted multi-pair relay communication. In the case of limited transmission power, with the goal of "maximizing system rate", the optimal HAP design is designed. Position and Transceiver Precoding.

SUMMARY OF THE INVENTION The present invention proposes a method for designing position and transceiving precoding in HAP-assisted multi-pair relay communication, which specifically includes the following steps:

(1) Build a HAP-assisted multi-pair relay amplification and forwarding system, the system includes: a HAP equipped with multiple antennas, a plurality of single-antenna transmitting end users, and a plurality of single-antenna receiving end users;

(2) All single-antenna transmitting end users and single-antenna receiving end users send uplink pilot signals to HAP, and HAP receives and performs channel estimation on the uplink pilot signals sent by all users to obtain partial CSI of all users;

(3) According to step (2), the partial CSI of all users is obtained, HAP calculates the transceiving precoding matrix, and calculates the optimal parameters in the precoding matrix and the optimal position of the HAP based on the maximizing system and rate, and enlarges it to the target user And forward the signal to be transmitted by the user at the sending end.

Further, described step (2) realization process is as follows:

HAP has N antennas, the sender user set is S, and the target user set is D. There are K single-antenna users in S and D, respectively marked as (S ₁ , S ₂ , S ₃ ,...,S _K ) and (D ₁ , D ₂ , D ₃ , . . . , D _K ); in the first time slot, for any user S _k at the sender, send information to the HAP; in the second time slot, the HAP amplifies the information and forwards it to the target User D _k ; HAP uses the uplink pilot signals sent by all users to estimate the channel, and the obtained partial CSI is expressed as:

和

分别表示HAP与发送端第k个用户之间和第k个目标用户之间的估计信道，k∈[1,2,…,K]；

和

是信道中的视距成分，向量大小分别为N×1和1×N；R_k和T_k是N×N的确定性非负定矩阵，分别表示接收信号和发送信号在HAP天线间的空间相关性；

和

都表示N×1的复高斯随机向量，其元素都服从均值为0、方差为

的独立同分布，

和

为信道估计参数，表示信道估计的准确度，

∈表示属于；

表示矩阵的平方根运算；(·)^H表示矩阵的共轭转置运算；用户集S的部分CSI表示为

矩阵大小为N×K，用户集D的部分CSI表示为

矩阵大小为K×N。in,

and

Represent the estimated channels between the HAP and the kth user at the sender and between the kth target user, k∈[1,2,…,K];

and

is the line-of-sight component in the channel, and the vector sizes are N×1 and 1×N, respectively; R _k and T _k are N×N deterministic non-negative definite matrices, representing the space between the received signal and the transmitted signal respectively between the HAP antennas Correlation;

and

Both represent an N×1 complex Gaussian random vector, and its elements all obey the mean value of 0 and the variance of

independent and identically distributed,

and

is the channel estimation parameter, indicating the accuracy of the channel estimation,

∈ means belong to;

Represents the square root operation of the matrix; (·) ^H represents the conjugate transpose operation of the matrix; the partial CSI of the user set S is expressed as

The matrix size is N×K, and the partial CSI of user set D is expressed as

The matrix size is K×N.

Further, the transceiving precoding matrix described in step (3) is:

α_G和α_H为正则化参数；ζ表示满足高空无人平台中继功率约束的归一化参数；Among them, the matrix size of W is N×N,

α _G and α _H are the regularization parameters; ζ represents the normalization parameters that satisfy the relay power constraints of the high-altitude unmanned platform;

Among them, _PR represents the power at the relay of the high-altitude unmanned platform, p=NP _T , P _T represents the transmit power of the users in the user set S, σ ² represents the noise power in the link of the first time slot segment, and I _N represents N-order identity matrix, (·) ^-1 represents the inversion operation of the matrix, and tr(·) represents the trace operation of the matrix.

的计算过程如下：Further, the optimal regularization parameter described in step (3)

The calculation process is as follows:

1) Set the initial values of the regularization parameters α _G and α _H , and substitute them into R _sum ;

2) exhaustively enumerate the HAP position coordinates in the two-dimensional plane, and retain the position when R _sum obtains the maximum value;

3) Substitute the gained position in R _sum in step 2), utilize the interior point method to obtain the α _G that makes R _sum obtain the maximum value at this moment, and record the α _G at this moment;

4) Substitute α _G into R _sum , utilize the interior point method to obtain the α _H that makes R _sum obtain the maximum value at this time, and record the α _H at this time;

5) Substitute α _G and α _H obtained in 3) and 4) into R _sum , and repeat steps 2)-4) until the rate R _sum converges, and the optimal regularization parameter is obtained

Further, the HAP optimal position is calculated by the following formula:

为最优的正则化参数，γ_k表示第k个用户的信干噪比，

表示关于

和

的期望，x^opt和y^opt分别表示优化后HAP在水平方向和垂直方向的最优位置。where R _sum represents the system and rate of the HAP relay system,

is the optimal regularization parameter, γ _k represents the signal-to-interference-noise ratio of the kth user,

express about

and

, x ^opt and y ^opt represent the optimal position of the optimized HAP in the horizontal and vertical directions, respectively.

Beneficial effects: Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The method adopts HAP as relay-assisted communication, and designs the transceiver precoding matrix according to part of the CSI of the user, so that in the HAP-assisted relay communication system The communication quality of the user is guaranteed, which has important practical significance; 2. This method aims at maximizing the system and rate, and makes full use of the characteristics of HAP to jointly optimize its location and transceiving precoding matrix, which is suitable for the actual communication scene, and has a great advantage. strong practicality.

Description of drawings

Fig. 1 is the flow chart of the present invention;

FIG. 2 is a schematic diagram of a HAP-assisted multi-pair relay amplifying and forwarding system.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings.

The present invention proposes a method for designing position and transceiving precoding in HAP-assisted multi-pair relay communication. First, a user sends an uplink pilot signal to the HAP, and the HAP receives and performs channel estimation on the uplink pilot signal sent by the user to Obtain part of the channel state information of the user; secondly, using the part of the channel state information of the user, HAP calculates the transceiving precoding matrix and calculates its own position based on the maximized system and rate, and amplifies and forwards the signal to be transmitted by the transmitting end user to the target user, such as As shown in Figure 1, it specifically includes the following steps:

Step 1: Build a HAP-assisted multi-pair relay amplification and forwarding system, as shown in Figure 2, including: a HAP equipped with multiple antennas, multiple single-antenna transmitting end users, and multiple single-antenna receiving end users.

Step 2: All single-antenna transmitting end users and single-antenna receiving end users send uplink pilot signals to the HAP, and the HAP receives and performs channel estimation on the uplink pilot signals sent by all users to obtain partial CSI of all users.

HAP has N antennas, the sender user set is S, and the target user set is D. There are K single-antenna users in S and D, respectively marked as (S ₁ , S ₂ , S ₃ ,...,S _K ) and (D ₁ , D ₂ , D ₃ , . . . , D _K ); in the first time slot, for any user S _k at the sender, send information to the HAP; in the second time slot, the HAP amplifies the information and forwards it to the target User _Dk . HAP uses the uplink pilot signal sent by the user to estimate the channel, and the obtained partial CSI is expressed as:

和

分别表示HAP与发送端第k个用户之间和第k个目标用户之间的估计信道，k∈[1,2,…,K]；

和

是信道中的视距成分，向量大小分别为N×1和1×N；R_k和T_k是N×N的确定性非负定矩阵，分别表示接收信号和发送信号在HAP天线间的空间相关性；

和

都表示N×1的复高斯随机向量，其元素都服从均值为0、方差为

的独立同分布，

和

为信道估计参数，表示信道估计的准确度，

∈表示属于；

表示矩阵的平方根运算；(·)^H表示矩阵的共轭转置运算；用户集S的部分CSI表示为

矩阵大小为N×K，用户集D的部分CSI表示为

矩阵大小为K×N。in,

and

Represent the estimated channels between the HAP and the kth user at the sender and between the kth target user, k∈[1,2,…,K];

and

is the line-of-sight component in the channel, and the vector sizes are N×1 and 1×N, respectively; R _k and T _k are N×N deterministic non-negative definite matrices, representing the space between the received signal and the transmitted signal respectively between the HAP antennas Correlation;

and

Both represent an N×1 complex Gaussian random vector, and its elements all obey the mean value of 0 and the variance of

independent and identically distributed,

and

is the channel estimation parameter, indicating the accuracy of the channel estimation,

∈ means belong to;

Represents the square root operation of the matrix; (·) ^H represents the conjugate transpose operation of the matrix; the partial CSI of the user set S is expressed as

The matrix size is N×K, and the partial CSI of user set D is expressed as

The matrix size is K×N.

Step 3: According to the partial CSI of the user obtained in step 2, the HAP calculates the transceiving precoding matrix, and calculates the optimal parameters in the precoding matrix and the optimal position of the HAP based on the maximizing system and rate, and amplifies and forwards it to the target user. The signal to be transmitted by the user at the sending end.

HAP calculates the transceiver precoding matrix as:

α_G和α_H为正则化参数；ζ表示满足高空无人平台中继功率约束的归一化参数。Among them, the matrix size of W is N×N,

α _G and α _H are the regularization parameters; ζ represents the normalization parameters that satisfy the relay power constraints of the high-altitude unmanned platform.

Among them, _PR represents the power at the relay of the high-altitude unmanned platform, p=NP _T , P _T represents the transmit power of the users in the user set S, σ ² represents the noise power in the first time slot link, and I _N represents N Order identity matrix, (·) ^-1 represents the inversion operation of the matrix, and tr(·) represents the trace operation of the matrix.

The regularization parameters α _G , α _H and HAP positions are calculated by:

表示HAP中继系统的系统和速率，

为最优的正则化参数，γ_k表示第k个用户的信干噪比，

表示关于

和

的期望，x^opt和y^opt分别表示优化后HAP在水平方向和垂直方向的最优位置。in,

Indicates the system and rate of the HAP relay system,

is the optimal regularization parameter, γ _k represents the signal-to-interference-noise ratio of the kth user,

express about

and

, x ^opt and y ^opt represent the optimal position of the optimized HAP in the horizontal and vertical directions, respectively.

The specific calculation method is as follows:

S1. Set the initial values of the regularization parameters α _G and α _H , and substitute them into R _sum ;

S2, exhaustively enumerate the HAP position coordinates in the two-dimensional plane, and retain the position when R _sum obtains the maximum value;

S3, substitute the gained position in step S2 in R _sum , utilize the inner point to send out and find out the α _G that makes R _sum obtain the maximum value at this moment, and record the α _G at this moment;

S4. Substitute α _G into R _sum , and use the interior point method to obtain the α _H that makes R _sum obtain the maximum value at this time, and record the α _H at this time;

和HAP的最优位置(x^opt,y^opt)。S5. Substitute α _G and α _H obtained in S3 and S4 into R _sum , and repeat steps S2-S4 until the rate R _sum converges, and the optimal regularization parameter is obtained

and the optimal position of the HAP (x ^opt , y ^opt ).

To sum up, this method considers the design of location and precoding in the HAP-assisted multi-pair relay communication system, to ensure the communication quality of users, and to ensure that the system rate can be improved to the greatest extent. In addition, part of the CSI is used in the design process of this method, which is more practical. Therefore, this method has strong practical feasibility and can be applied to actual communication scenarios.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this, any person familiar with the technology can understand the transformation or replacement that comes to mind within the technical scope disclosed by the present invention, All should be included within the scope of the present invention. The HAP described in the present invention includes unmanned airships, unmanned aerial vehicles, manned aerial vehicles or other aerial objects carrying a certain payload. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (2)

1. a position in HAP-assisted multiple pairs of relay communications and a method for designing transceiver precoding, is characterized in that, comprises the following steps: (1) Build a HAP-assisted multi-pair relay amplification and forwarding system, the system includes: a HAP equipped with multiple antennas, a plurality of single-antenna transmitting end users, and a plurality of single-antenna receiving end users; (2) All single-antenna transmitting end users and single-antenna receiving end users send uplink pilot signals to HAP, and HAP receives and performs channel estimation on the uplink pilot signals sent by all users to obtain partial CSI of all users; (3) According to step (2), the partial CSI of all users is obtained, HAP calculates the transceiving precoding matrix, and calculates the optimal parameters in the precoding matrix and the optimal position of the HAP based on the maximizing system and rate, and enlarges it to the target user And forward the signal to be transmitted by the sender user; The HAP calculates the transceiver precoding matrix as:

Among them, the matrix size of W is N×N,

α _G and α _H are regularization parameters; ζ represents the normalization parameters that satisfy the relay power constraints of high-altitude unmanned platforms:

Among them, _PR represents the power at the relay of the high-altitude unmanned platform, p=NP _T , P _T represents the transmit power of the users in the user set S, σ ² represents the noise power in the first time slot link, and I _N represents N Order identity matrix, ( ) ^-1 represents the inversion operation of the matrix, and tr( ) represents the trace operation of the matrix; The regularization parameters α _G , α _H and HAP positions are calculated by:

in,

Indicates the system and rate of the HAP relay system,

is the optimal regularization parameter, γ _k represents the signal-to-interference-noise ratio of the kth user,

express about

and

, x ^opt and y ^opt represent the optimal positions of the optimized HAP in the horizontal and vertical directions, respectively; The optimal regularization parameter

The calculation process is as follows: S1. Set the initial values of the regularization parameters α _G and α _H , and substitute them into R _sum ; S2, exhaustively enumerate the HAP position coordinates in the two-dimensional plane, and retain the position when R _sum obtains the maximum value; S3, substitute the gained position in step S2 in R _sum , utilize the inner point to send out and find out the α _G that makes R _sum obtain the maximum value at this moment, and record the α _G at this moment; S4. Substitute α _G into R _sum , and use the interior point method to obtain the α _H that makes R _sum obtain the maximum value at this time, and record the α _H at this time; S5. Substitute α _G and α _H obtained in S3 and S4 into R _sum , and repeat steps S2-S4 until the rate R _sum converges, and the optimal regularization parameter is obtained

and the optimal position of the HAP (x ^opt , y ^opt ). 2. the position in the HAP-assisted multi-pair relay communication according to claim 1 and the sending and receiving precoding design method, it is characterized in that, described step (2) realization process is as follows: HAP has N antennas, the sender user set is S, and the target user set is D. There are K single-antenna users in S and D, respectively marked as (S ₁ , S ₂ , S ₃ ,...,S _K ) and (D ₁ , D ₂ , D ₃ , . . . , D _K ); in the first time slot, for any user S _k at the sender, send information to the HAP; in the second time slot, the HAP amplifies the information and forwards it to the target User D _k ; HAP uses the uplink pilot signals sent by all users to estimate the channel, and the obtained partial CSI is expressed as:

in,

and

Represent the estimated channel between the HAP and the kth user at the sender and between the kth target user, k∈[1, 2,…,K];

and

is the line-of-sight component in the channel, and the vector sizes are N×1 and 1×N, respectively; R _k and T _k are N×N deterministic non-negative definite matrices, representing the space between the received signal and the transmitted signal respectively between the HAP antennas Correlation;

and

Both represent an N×1 complex Gaussian random vector, and its elements all obey the mean value of 0 and the variance of

independent and identically distributed,

and

is the channel estimation parameter, indicating the accuracy of the channel estimation,

∈ means belong to;

Represents the square root operation of the matrix; (·) ^H represents the conjugate transpose operation of the matrix; the partial CSI of the user set S is expressed as

The matrix size is N×K, and the partial CSI of user set D is expressed as

The matrix size is K×N.

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