WO2022016856A1

WO2022016856A1 - Cooperative receiving method and system based on air interface information fusion

Info

Publication number: WO2022016856A1
Application number: PCT/CN2021/076436
Authority: WO
Inventors: 刘安; 刘冠颖; 赵民建
Original assignee: 浙江大学
Priority date: 2020-07-21
Filing date: 2021-02-10
Publication date: 2022-01-27

Abstract

Disclosed in the present invention are a cooperative receiving method and system based on air interface information fusion: removing the phase rotation of a channel to a first channel coding signal to obtain a second channel coding signal; selecting cooperative receivers in a set signal-to-noise ratio range of the second channel coding signal and controlling same to calculate a log likelihood ratio; by means of an air interface information fusion method, transmitting the log likelihood ratio information of (Q-1) cooperative receivers to the remaining cooperative receiver; controlling the remaining cooperative receiver to integrate the log likelihood ratio information of Q cooperative receivers and, on the basis of the integrated log likelihood ratio information, decoding the first channel coding signal to obtain a decoding result. The present invention can greatly reduce cooperative decoding latency, reduce the bit error rate, support more receivers to implement cooperation, and increase the system scalability.

Description

Method and system for cooperative reception based on air interface information fusion

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority of the Chinese patent application number "202011157897.0", which was filed by Zhejiang University on October 26, 2020, with the invention titled "Method and System for Collaborative Reception Based on Air Interface Information Fusion".

This application claims the priority of the Chinese Patent Application No. "202010702911.4", which was submitted by Zhejiang University on July 21, 2020, with the title of "A Method and System for Collaborative Reception Based on Air Interface Information Fusion".

technical field

The present invention relates to the technical field of wireless communication, and in particular, to a cooperative receiving method and system based on air interface information fusion.

Background technique

In recent years, cooperative communication technology has become one of the hot research fields of wireless communication. Cooperative reception technology improves wireless network capacity and bit error rate performance by combining received signals from multiple receivers in a wireless network to form a virtual antenna array to increase diversity and power gain, thereby increasing the likelihood of successfully decoding noisy transmissions potential. Cooperative reception may also result in increased communication range, increased data rate and/or reduced transmit power.

The existing cooperative reception technologies can be roughly divided into the following categories:

a. Each receiver broadcasts its received signal on the local area network, and then performs maximum ratio combining at the fusion center to achieve diversity gain. However, this method has extremely high requirements on the throughput of the network, and it is difficult for the actual network to meet its requirements.

b. Some or all nodes among the receivers simply exchange hard decision information, and each receiver performs decoding and demodulation according to itself and the received hard decision information. Although this method has lower requirements on the throughput of the network, the exchange of hard-decision information may lead to a certain loss of the final decoding performance.

c. Each receiver in the receive cluster demodulates the transmission locally and generates a log-likelihood ratio. All receiving nodes (or a subset of nodes with better channel quality) quantize their log-likelihood ratios and broadcast all their quantized values over the network to other receiving nodes in the cluster. Each receiving node then combines the information received over the network with its local unquantized log-likelihood ratio and passes these results to its local block decoder for decoding. If any receiving node successfully decodes the message, it forwards the decoded message over the network to other receiving nodes in the cluster. Each receiving node will transmit the log-likelihood ratio value through the network, in order to avoid inter-node interference, each node needs to allocate orthogonal radio resources. In this method, when the number of receivers is large, the calculation latency will be greatly increased, so that the problem of poor network scalability will occur.

It can be seen from this that the current cooperative reception technology has defects such as high bit error rate, prolonged interaction time, and poor network scalability.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

To this end, an object of the present invention is to propose a cooperative receiving method based on air interface information fusion. Air interface fusion and fusion receivers use the log-likelihood ratio information of air interface fusion to decode four parts, which can greatly reduce the cooperative decoding delay, reduce the bit error rate, support more receivers to cooperate, and improve the scalability of the system .

Another object of the present invention is to propose a cooperative receiving system based on air interface information fusion.

In order to achieve the above object, an embodiment of the present invention proposes a cooperative receiving method based on air interface information fusion, which includes the following steps: simultaneously sending a first channel coded signal to N cooperative receivers, where N is a set constant; Rotate the phase of the first channel-coded signal to obtain a second channel-coded signal; calculate the signal-to-noise ratio of the second channel-coded signal of the N cooperative receivers, and select Q from the N cooperative receivers In the cooperative receivers within the set signal-to-noise ratio range, the log-likelihood ratio is calculated according to the second channel coded signals of the Q cooperative receivers, where Q is a positive integer, Q≤N; from the Q cooperative receivers randomly select a cooperative receiver in the machine as a fusion receiver, and transmit the log-likelihood ratios of the remaining (Q-1) cooperative receivers to the fusion receiver by means of air interface information fusion; control the The fusion receiver integrates the log-likelihood ratio information of the Q cooperative receivers, and decodes the first channel coded signal according to the integrated log-likelihood ratio information to obtain a decoding result; Broadcast to (N-1) cooperative receivers other than the fusion receiver.

The cooperative receiving method based on air interface information fusion according to the embodiment of the present invention obtains the second channel coded signal by eliminating the phase rotation of the first channel coded signal by the channel; , control the calculation of the log-likelihood ratio, and transmit the log-likelihood ratio information of (Q-1) cooperative receivers to the remaining cooperative receivers by means of air interface information fusion; control the remaining cooperative receivers The cooperative receiver integrates the log-likelihood ratio information of the Q cooperative receivers, and decodes the first channel coded signal according to the integrated log-likelihood ratio information to obtain a decoding result; thus, the cooperative decoding time can be greatly reduced. Delay, reduce the bit error rate, support more receivers to cooperate, and improve the scalability of the system.

In addition, the cooperative receiving method based on air interface information fusion according to the foregoing embodiments of the present invention may also have the following additional technical features:

Further, in an embodiment of the present invention, the canceling the phase rotation of the first channel coded signal by the channel to obtain the second channel coded signal includes: sending a pilot signal to the N cooperative receivers; Estimate the channel according to the pilot signal by using the least square method or the minimum mean square error method, and calculate the signal-to-noise ratio of the pilot signal according to the channel estimation result; send the first signal to the N cooperative receivers Channel coded signal; use the signal-to-noise ratio of the pilot signal to cancel the phase rotation of the first channel coded signal to obtain the second channel coded signal.

Further, in an embodiment of the present invention, the second channel coded signal is:

Y _i [m,l]＝|h _i [m]|X[m,l]+W _i [m,l],

Wherein, Y _i [m, l] is expressed as the m-th block of the i-th receiver cooperating second channel encoded signal in the l-th transmission symbol, h _i [m] is expressed as the first channel encoded signal The forward link complex channel through which the mth block signal in the ith cooperative receiver passes through, X[m,l] is represented as the lth block signal in the mth block signal of the first channel coded signal There are k transmission symbols in the m-th block signal of the first channel coded signal, and the k transmission symbols are represented by a set as X={x ₁ , . . . , x _k }, X[m ,l] is selected from the set X with equal probability, W _i [m,l] is expressed as the baseband matching of the lth transmitted symbol in the mth block signal of the second channel coded signal by the ith cooperative receiver The noise generated after filtering, W _i [m,l] follows a complex Gaussian distribution _{with mean 0 and variance N 0.}

Further, in an embodiment of the present invention, the calculation formula of the signal-to-noise ratio of the second channel-coded signal is:

Wherein, ρ _i represents the signal-to-noise ratio of the mth block signal in the second channel coded signal of the ith cooperative receiver, and h _i [m] represents the mth block signal in the first channel coded signal the forward link complex channel passed to the i-th cooperative receiver,

is the noise variance generated by the i-th cooperative receiver, X[m,l] is the l-th transmitted symbol in the m-th block signal of the first channel-coded signal, and E _{s is the first channel-coded signal.} The average energy of each transmitted symbol in the mth block of the channel coded signal, E(·) represents the mean value, and k represents the number of transmitted symbols in the mth block of the first channel coded signal.

Further, in an embodiment of the present invention, the calculation formula of the log-likelihood ratio is:

in,

It is expressed as the log-likelihood ratio of the transmitted symbol x _k calculated by the ith cooperative receiver according to the second channel coded signal Y _i _{[m,l], where x l} is the transmitted symbol set X={x ₁ , ..., x _k } in the l-th transmitted symbol, p _Y/X (Y _i [m,l])=x _l |X[m,l]=x _{k is} expressed as m a first block of the first channel coded signal under the condition of the k-th symbol, the receiver obtains the i-th collaboration probability of a symbol in the first set of demodulated symbol l, P _i represents the probability of error.

Further, in an embodiment of the present invention, the method of transmitting the log-likelihood ratios of the remaining (Q-1) cooperative receivers to the fusion receiver by means of air interface information fusion includes: A normalized signal obtained by multiplying the log-likelihood ratio of the (Q-1) cooperative receivers by a normalization factor b, and the normalized signal is repeatedly sent to the fusion receiver Z times, Z is to set a constant; the fusion receiver receives the normalized signal through the normalization factor a to obtain a received signal, and the received signal is expressed as:

in,

Denotes that the zth received signal of the fusion receiver is the sum of the log-likelihood ratios of the (Q-1) cooperative receivers with respect to the kth transmitted symbol,

is the channel coefficient between the i-th user and the fusion receiver, n ^z is the white Gaussian noise generated by the fusion receiver,

represents the log-likelihood ratio of the i-th cooperative receiver with respect to the transmitted symbol x _{k, normalization factor}

and a ^z according to the received signal of Z times

The sum of the smallest received signal in and the log-likelihood ratio values of the (Q-1) receivers for the kth transmitted symbol

The mean square error of the joint design.

Further, in an embodiment of the present invention, the controlling the fusion receiver to integrate the log-likelihood ratio information of the Q cooperative receivers includes: controlling the fusion receiver to integrate the Z times received signals Merge to obtain final log-likelihood ratio information, the final log-likelihood ratio information is:

Compare the final log-likelihood ratio information r _k to the log-likelihood ratio of the fusion receiver

Add up to obtain the integrated log-likelihood ratio information about the k-th symbol in the transmitted symbol set X={x ₁ ,...,x _{k }}

Further, in an embodiment of the present invention, the decoding of the first channel-coded signal according to the integrated log-likelihood ratio information to obtain a decoding result includes: determining a set of transmitted symbols X={x ₁ , ..., x _k} for each transmission symbol the number of air interface is performed after the fusion maximum likelihood ratio information; determined according to the logarithmic likelihood ratio of the maximum value of the first information signal corresponding to the channel coding The position sequence number of the l-th transmitted symbol in the m-th block signal in the set X; that is:

Where k ^* is the position sequence number of the lth transmitted symbol in the mth block signal of the first channel coded signal in the transmission set X; the decoding result obtained by the fusion receiver determined according to the position sequence number is: :

in,

is represented as the transmitted symbol of the k- ^th position sequence number in the transmitted symbol set X.

In order to achieve the above object, another embodiment of the present invention proposes a cooperative receiving system based on air interface information fusion, including: a transmitter for simultaneously sending a first channel coded signal to N cooperative receivers, where N is a setting constant; the cooperative receiver is used to eliminate the phase rotation of the channel to the first channel coded signal to obtain the second channel coded signal; the log-likelihood ratio calculation module is used to calculate the second channel coded signal of the N cooperative receivers The signal-to-noise ratio of the channel-coded signal, select Q cooperative receivers within the set signal-to-noise ratio range from the N cooperative receivers, and calculate the log-likelihood according to the second channel-coded signal of the Q cooperative receivers ratio, where Q is a positive integer, Q≤N; the air interface information fusion transmission module is used to arbitrarily select a cooperative receiver from the Q cooperative receivers as a fusion receiver, and use the air interface information fusion method to fuse the remaining The log-likelihood ratios of the (Q-1) cooperative receivers are transmitted to the fusion receiver; an information integration module is used to control the fusion receiver to integrate the log-likelihoods of the Q cooperative receivers ratio information; a decoding module for decoding the first channel coded signal according to the integrated log-likelihood ratio information to obtain a decoding result; a propagation module for broadcasting the decoding result to the fusion receiver (N-1) cooperative receivers other than the machine.

The cooperative receiving system based on air interface information fusion according to the embodiment of the present invention obtains the second channel coded signal by eliminating the phase rotation of the channel to the first channel coded signal; the selection is within the range of the set signal-to-noise ratio of the second channel coded signal. , control the calculation of the log-likelihood ratio, and transmit the log-likelihood ratio information of (Q-1) cooperative receivers to the remaining cooperative receivers by means of air interface information fusion; control the remaining cooperative receivers The cooperative receiver integrates the log-likelihood ratio information of the Q cooperative receivers, and decodes the first channel coded signal according to the integrated log-likelihood ratio information to obtain a decoding result; thus, the cooperative decoding time can be greatly reduced. Delay, reduce the bit error rate, support more receivers to cooperate, and improve the scalability of the system.

In addition, the cooperative receiving system based on air interface information fusion according to the foregoing embodiments of the present invention may also have the following additional technical features:

Further, in an embodiment of the present invention, the air interface information fusion transmission module includes: a normalized information transmission module, configured to multiply the log-likelihood ratios of the (Q-1) cooperative receivers by The normalized signal obtained by the normalization factor b is repeatedly sent to the fusion receiver Z times, and Z is a set constant; the normalization information receiving module is used to pass the fusion receiver through the normalization factor a. The normalized signal is received to obtain a received signal.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a flowchart of a cooperative receiving method based on air interface information fusion according to an embodiment of the present invention;

2 is a schematic structural diagram of a cooperative receiving system based on air interface information fusion according to an embodiment of the present invention;

FIG. 3 is a relationship diagram of a transmitter and a cooperative receiver in a cooperative receiving system based on air interface information fusion according to an embodiment of the present invention.

detailed description

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

The purpose of the present invention is to provide a cooperative receiving method and system based on air interface information fusion, so as to support more cooperative receivers to cooperate with each other, reduce the bit error rate and decoding delay, and improve the scalability of the system.

The method and system for cooperative reception based on air interface information fusion proposed according to the embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a flowchart of a cooperative reception method based on air interface information fusion according to an embodiment of the present invention.

As shown in Figure 1, the cooperative receiving method and system based on air interface information fusion includes the following steps:

In step S101, the first channel coding signal is simultaneously sent to N cooperative receivers, where N is a set constant.

Among them, N cooperative receivers are receiving clusters.

In step S102, the phase rotation of the channel to the first channel coded signal is eliminated to obtain the second channel coded signal.

Specifically, step S102 includes:

Step S21, sending pilot signals to N cooperative receivers;

Step S22, using the least square method or the minimum mean square error method to estimate the channel according to the pilot signal, and calculate the signal-to-noise ratio of the pilot signal according to the channel estimation result;

Step S23, sending the first channel coding signal to the N cooperative receivers;

Step S24, cancel the phase rotation of the first channel coded signal by using the signal-to-noise ratio of the pilot signal to obtain the second channel coded signal.

By eliminating the phase rotation of the channel to the first channel coded signal, it can ensure that the signal received by the cooperative receiver is completely consistent with the signal sent by the transmitter, and then the log-likelihood of the received signal of the cooperative receiver can be used to compare the signal sent by the transmitter. When the signal is decoded, the accuracy of the decoding result can be improved and the bit error rate can be reduced.

In one embodiment of the present invention, the second channel coded signal is represented as:

Y _i [m,l]＝|h _i [m]|X[m,l]+W _i [m,l]

Wherein, Y _i [m,l] represents the l-th transmitted symbol in the m-th block of the second channel-coded signal of the i-th cooperative receiver, and hi [m] represents the m- _{th symbol in the first channel-coded signal} The forward link complex channel that the block signal passes through when it reaches the i-th cooperative receiver, X[m,l] represents the l-th transmitted symbol in the m-th block signal of the first channel-coded signal, the first channel-coded signal There are k transmitted symbols in the mth block of the signal, and the k transmitted symbols are represented by sets as X={x ₁ ,...,x _k }, and X[m,l] is selected from the set X with equal probability, W _i [m,l] represents the noise generated by the ith cooperative receiver performing baseband matched filtering on the lth transmitted symbol in the mth block signal of the second channel coded signal, and W _i [m,l] obeys A complex Gaussian distribution with a mean value of 0 and a variance of N ₀ _{, namely W i} [m,l]～CN(0,N ₀ ).

In step S103, the signal-to-noise ratios of the second channel coded signals of the N cooperative receivers are calculated, and Q cooperative receivers within the set signal-to-noise ratio range are selected from the N cooperative receivers, and according to the Q cooperative receivers The log-likelihood ratio is calculated from the second channel coded signal of the engine, where Q is a positive integer, and Q≤N.

In an embodiment of the present invention, the calculation formula of the signal-to-noise ratio of the second channel coded signal is:

Wherein, ρ _i represents the SNR of the m-th block of the second channel signal i-th coded signal receiver in the cooperative, h _i [m] is expressed as the m-th signal block a first channel encoded signal to the i-th The forward link complex channel traversed by the cooperative receiver,

is the noise variance generated by the i-th cooperative receiver, X[m,l] is the l-th transmitted symbol in the m-th block signal of the _{first channel-coded signal, and E s} is the m-th signal of the first channel-coded signal. The average energy of each transmitted symbol in the block signal, E(·) represents the mean value, and k represents the number of transmitted symbols in the mth block signal of the first channel-coded signal.

The formula for calculating the log-likelihood ratio is:

in,

It is expressed as the log-likelihood ratio of the transmitted symbol x _k calculated by the ith cooperative receiver according to the second channel coded signal Y _i _{[m,l], where x l} is the transmitted symbol set X={x ₁ , . . . ., x _k } in the l-th transmitted symbol, p _Y/X (Y _i [m,l])=x _l |X[m,l]=x _k indicates that what is sent by the transmitter is the first channel code Under the condition of the k-th symbol in the m-th block of the signal, the probability of obtaining the l-th symbol in the symbol set after demodulation by the i-th cooperative receiver, p _i represents the error probability,

υ is the setting constant.

Error probability p ⁱ related to the channel transition probability. For example, for having

BPSK modulation method,

for having

QPSK modulation method,

in,

erfc(β)=1-erf(β), erf is the cumulative function of standard normal distribution, namely:

By calculating the log-likelihood ratio of the cooperative receivers within the set signal-to-noise ratio range, the time required for all cooperative receivers to calculate the log-likelihood ratio can be shortened and the delay can be reduced; The range of SNR can reduce the influence of cooperative receivers with low SNR, and use the log-likelihood ratio of cooperative receivers with high SNR to perform decoding, which can improve the accuracy of decoding and reduce the bit error rate.

In step S104, randomly select one cooperative receiver from the Q cooperative receivers as a fusion receiver, and transmit the log-likelihood ratios of the remaining (Q-1) cooperative receivers by means of air interface information fusion. to the fusion receiver.

Specifically, step S104 includes:

In step S41, the normalized signal obtained by multiplying the log-likelihood ratios of the (Q-1) cooperative receivers by the normalization factor b is repeatedly sent to the fusion receiver Z times, where Z is a set constant;

Step S42, the fusion receiver receives the normalized signal through the normalization factor a to obtain the received signal; the received signal is expressed as:

in,

The zth received signal of the fusion receiver is expressed as the sum of the log-likelihood ratios of the (Q-1) cooperative receivers about the kth transmitted symbol,

is the channel coefficient between the ith user and the fusion receiver, n ^z is the white Gaussian noise generated by the fusion receiver,

and a ^z according to the received signal of Z times

The mean square error of the joint design,

P' is the peak power limit of each (Q-1) cooperative receiver. Without loss of generality, in the zth transmission, the channels traversed by (Q-1) cooperative receivers

That is, it can always be guaranteed that the users are sorted according to their channel strengths, and that the channel strengths passed by the (Q-1) cooperative receivers increase sequentially during the zth retransmission. To achieve a smaller MSE, the normalization factor

and the optimal coefficients of ^{a z can be designed as}

Due to the sum of the log-likelihood ratios of the (Q-1) cooperative receivers received by the fusion receiver for the zth time with respect to the kth transmitted symbol

There is noise, and the received signal is further reduced by combining after repeated transmission

and the sum of the log-likelihood ratio values of the (Q-1) cooperative receivers for the kth transmitted symbol

The mean square error between the two can improve the signal-to-noise ratio of the received signal of the fusion receiver, thereby reducing the influence of noise when the received signal is subsequently used for decoding, improving the accuracy of decoding, and reducing the bit error rate.

The cooperative receiver uses the log-likelihood ratio of the superposition characteristic of the wireless channel to directly perform air interface information fusion. The fusion receiver only needs to decode according to the sum of the log-likelihood ratios of Q receivers, without paying attention to each receiver. It can avoid that each cooperative receiver needs to broadcast its log-likelihood ratio to other receivers in a time-sharing manner. When the number of cooperative receivers increases and the channel conditions are poor, the LLR transmission delay will be greatly increased. The defects of low LLR transmission efficiency between cooperative receivers, large cooperative decoding delay, and poor system scalability will occur. The transmission efficiency of log-likelihood ratio is improved, the cooperative decoding delay is reduced, and the scalability of the system is improved.

In step S105, the fusion receiver is controlled to integrate the log-likelihood ratio information of the Q cooperative receivers, and decode the first channel coded signal according to the integrated log-likelihood ratio information to obtain a decoding result.

Specifically, step S105 includes:

Step S51, control the fusion receiver to combine the received signals of the Z times to obtain the final log-likelihood ratio information

Step S52, compare the final log-likelihood ratio information r _k with the log-likelihood ratio of the fusion receiver

Step S53, determine the maximum value of log-likelihood ratio information after air interface fusion for each transmitted symbol in the set of transmitted symbols X={x ₁ ,...,x _{k }, and the log-likelihood ratio information after air interface fusion} for

Step S54, according to the maximum value of the log-likelihood ratio information, determine the position sequence number of the lth transmission symbol in the set X corresponding to the mth block signal of the first channel-coded signal; namely:

Wherein k ^* is the position sequence number of the lth transmission symbol in the transmission set X in the mth block signal of the first channel coded signal;

In step S55, the decoding result obtained by the fusion receiver is determined according to the position sequence number as:

in

Expressed as a transmission symbol set X position of the first k ^* number of transmission symbol.

It should be noted that the transmitted symbol corresponding to the maximum value of the log-likelihood ratio information is the most likely symbol transmitted by the transmitter, and decoding is implemented.

In step S106, the decoding result is broadcast to (N-1) cooperative receivers other than the fusion receiver.

According to the cooperative receiving method based on air interface information fusion proposed in the embodiment of the present invention, by processing the signal sent by the transmitter and eliminating the phase rotation of the transmitted signal by the channel, the signal received by the cooperative receiver and the signal sent by the transmitter can be guaranteed. When the signal sent by the transmitter is decoded by using the log-likelihood ratio of the received signal of the cooperative receiver, the accuracy of the decoding result can be improved and the bit error rate can be reduced; It can shorten the time that all cooperative receivers need to calculate the log-likelihood ratio, and reduce the delay; the log-likelihood ratio of the cooperative receiver is used for air interface fusion and the fusion receiver utilizes the log-likelihood ratio. The log-likelihood ratio information of air interface fusion is decoded, that is, the log-likelihood ratio of the wireless channel is used to directly fuse the air interface information. Decoding without paying attention to the LLR of each receiver can avoid the need for each cooperative receiver to broadcast its own log-likelihood ratio to other receivers in time division. When the number of cooperative receivers increases and the channel conditions are poor, LLR transmission The delay will be greatly increased, resulting in the defects of low LLR transmission efficiency between cooperative receivers, large cooperative decoding delay, and poor system scalability. Extend and improve the scalability of the system.

Next, a cooperative receiving system based on air interface information fusion proposed according to an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a schematic structural diagram of a cooperative receiving system based on air interface information fusion according to an embodiment of the present invention.

As shown in FIG. 2 , the cooperative receiving system based on air interface information fusion includes: a transmitter 100 , a cooperative receiver 200 , a log-likelihood ratio calculation module 300 , an air interface information fusion transmission module 400 , an information integration module 500 , and a decoding module 600 and propagation module 700.

The transmitter 100 is used to send the first channel coded signal to N cooperative receivers at the same time, and N is a set constant; the cooperative receiver 200 is used to cancel the phase rotation of the first channel coded signal by the channel to obtain the second channel code signal; the log-likelihood ratio calculation module 300 is used to calculate the signal-to-noise ratio of the second channel-coded signal of the N cooperative receivers, and select Q cooperative receivers within the set signal-to-noise ratio range from the N cooperative receivers machine, calculates the log-likelihood ratio according to the second channel coded signals of the Q cooperative receivers, wherein Q is a positive integer, Q≤N; the air interface information fusion transmission module 400 is used to arbitrarily select one from the Q cooperative receivers The cooperative receiver acts as a fusion receiver, and transmits the log-likelihood ratios of the remaining (Q-1) cooperative receivers to the fusion receiver by means of air interface information fusion; the information integration module 500 is used to control the fusion receiver Integrate the log-likelihood ratio information of the Q cooperative receivers; the decoding module 600 is used to decode the first channel coded signal according to the integrated log-likelihood ratio information to obtain a decoding result; the propagation module 700 is used to decode the decoding The results are broadcast to (N-1) cooperative receivers other than the fused receiver.

It can be understood that the system 10 in this embodiment of the present invention sends the first encoded signal through the transmitter, the cooperative receiver calculates the log-likelihood ratio, the cooperative receiver performs air interface fusion on the log-likelihood ratio, and the fusion receiver uses air interface fusion. It can greatly reduce the cooperative decoding delay, reduce the bit error rate, support more receivers to cooperate, and improve the scalability of the system. The relationship between the transmitter and the cooperative receiver in the cooperative receiving system based on air interface information fusion is shown in FIG. 3 .

Further, in an embodiment of the present invention, the air interface information fusion transmission module includes: a normalized information sending module and a normalized information receiving module.

The normalized information sending module is used to multiply the normalized signals obtained by multiplying the log-likelihood ratios of the (Q-1) cooperative receivers by the normalization factor b, and repeatedly send them to the fusion receiver Z times, Z is a set constant; the normalization information receiving module is used to receive the normalized signal by the fusion receiver through the normalization factor a to obtain the received signal.

It should be noted that the foregoing explanation of the embodiment of the cooperative receiving method based on air interface information fusion is also applicable to the cooperative receiving system based on air interface information fusion in this embodiment, and details are not repeated here.

According to the cooperative receiving system based on air interface information fusion proposed in the embodiment of the present invention, by processing the signal sent by the transmitter and eliminating the phase rotation of the transmitted signal by the channel, the signal received by the cooperative receiver and the signal sent by the transmitter can be guaranteed. When the signal sent by the transmitter is decoded by using the log-likelihood ratio of the received signal of the cooperative receiver, the accuracy of the decoding result can be improved and the bit error rate can be reduced; It can shorten the time that all cooperative receivers need to calculate the log-likelihood ratio, and reduce the delay; the log-likelihood ratio of the cooperative receiver is used for air interface fusion and the fusion receiver utilizes the log-likelihood ratio. The log-likelihood ratio information of air interface fusion is decoded, that is, the log-likelihood ratio of the wireless channel is used to directly fuse the air interface information. Decoding without paying attention to the LLR of each receiver can avoid the need for each cooperative receiver to broadcast its own log-likelihood ratio to other receivers in time division. When the number of cooperative receivers increases and the channel conditions are poor, LLR transmission The delay will be greatly increased, resulting in the defects of low LLR transmission efficiency between cooperative receivers, large cooperative decoding delay, and poor system scalability. Extend and improve the scalability of the system.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims

A cooperative receiving method based on air interface information fusion, is characterized in that, comprises the following steps:

Simultaneously send the first channel coding signal to N cooperative receivers, where N is a set constant;

canceling the phase rotation of the channel to the first channel coded signal to obtain a second channel coded signal;

Calculate the signal-to-noise ratio of the second channel coded signal of the N cooperative receivers, select Q cooperative receivers within the range of the set signal-to-noise ratio from the N cooperative receivers, according to the Q cooperative receivers Calculate the log-likelihood ratio of the second channel-coded signal of , where Q is a positive integer, and Q≤N;

A cooperative receiver is arbitrarily selected from the Q cooperative receivers as a fusion receiver, and the log-likelihood ratios of the remaining (Q-1) cooperative receivers are transmitted to the fusion receiver;

Controlling the fusion receiver to integrate the log-likelihood ratio information of the Q cooperative receivers, and decoding the first channel-coded signal according to the integrated log-likelihood ratio information to obtain a decoding result;

The decoding result is broadcast to (N-1) cooperative receivers other than the fusion receiver.
The method according to claim 1, wherein the phase rotation of the first channel coded signal by the canceling channel to obtain the second channel coded signal comprises:

sending pilot signals to the N cooperative receivers;

Estimate the channel according to the pilot signal by using the least square method or the minimum mean square error method, and calculate the signal-to-noise ratio of the pilot signal according to the channel estimation result;

sending the first channel-coded signal to the N cooperative receivers;

Using the signal-to-noise ratio of the pilot signal to cancel the phase rotation of the first channel coded signal, the second channel coded signal is obtained.
The method according to claim 2, wherein the second channel coded signal is:

Y i [m,l]＝|h i [m]|X[m,l]+W i [m,l],

Wherein, Y i [m, l] is expressed as the m-th block of the i-th receiver cooperating second channel encoded signal in the l-th transmission symbol, h i [m] is expressed as the first channel encoded signal The forward link complex channel through which the mth block signal in the ith cooperative receiver passes through, X[m,l] is represented as the lth block signal in the mth block signal of the first channel coded signal There are k transmission symbols in the m-th block signal of the first channel coded signal, and the k transmission symbols are represented by a set as X={x 1 , . . . , x k }, X[m ,l] is selected from the set X with equal probability, W i [m,l] is expressed as the baseband matching of the lth transmitted symbol in the mth block signal of the second channel coded signal by the ith cooperative receiver The noise generated after filtering, W i [m,l] follows a complex Gaussian distribution with mean 0 and variance N 0.
The method according to any one of claims 1 to 3, wherein the calculation formula of the signal-to-noise ratio of the second channel-coded signal is:

Wherein, ρ i represents the signal-to-noise ratio of the mth block signal in the second channel coded signal of the ith cooperative receiver, and h i [m] represents the mth block signal in the first channel coded signal the forward link complex channel passed to the i-th cooperative receiver,
is the noise variance generated by the i-th cooperative receiver, X[m,l] is the l-th transmitted symbol in the m-th block signal of the first channel-coded signal, and E s is the first channel-coded signal. The average energy of each transmitted symbol in the mth block of the channel coded signal, E(·) represents the mean value, and k represents the number of transmitted symbols in the mth block of the first channel coded signal.
The method according to any one of claims 1 to 4, wherein the calculation formula of the log-likelihood ratio is:

in,
It is expressed as the log-likelihood ratio of the transmitted symbol x k calculated by the ith cooperative receiver according to the second channel coded signal Y i [m,l], where x l is the transmitted symbol set X={x 1 , ..., x k } in the l-th transmitted symbol, p Y/X (Y i [m,l])=x l |X[m,l]=x k is expressed as m a first block of the first channel coded signal under the condition of the k-th symbol, the receiver obtains the i-th collaboration probability of a symbol in the first set of demodulated symbol l, P i represents the probability of error.
The method according to any one of claims 1 to 5, wherein the log-likelihood ratios of the remaining (Q-1) cooperative receivers are transmitted to the Fusion receiver, including:

A normalized signal obtained by multiplying the log-likelihood ratio of the (Q-1) cooperative receivers by a normalization factor b, and repeating the normalized signal to the fusion receiver Z times, Z is the setting constant;

The fusion receiver receives the normalized signal through the normalization factor a to obtain a received signal, and the received signal is expressed as:

in,
Denotes that the zth received signal of the fusion receiver is the sum of the log-likelihood ratios of the (Q-1) cooperative receivers with respect to the kth transmitted symbol,
is the channel coefficient between the i-th user and the fusion receiver, n z is the white Gaussian noise generated by the fusion receiver,
represents the log-likelihood ratio of the i-th cooperative receiver with respect to the transmitted symbol x k, normalization factor
and a z according to the received signal of Z times
The sum of the smallest received signal in and the log-likelihood ratio values of the (Q-1) receivers for the kth transmitted symbol
The mean square error of the joint design.
The method according to claim 6, wherein the controlling the fusion receiver to integrate the log-likelihood ratio information of the Q cooperative receivers comprises:

The fusion receiver is controlled to combine the Z received signals to obtain final log-likelihood ratio information, where the final log-likelihood ratio information is:

Compare the final log-likelihood ratio information r k to the log-likelihood ratio of the fusion receiver
Add up to obtain the integrated log-likelihood ratio information about the k-th symbol in the transmitted symbol set X={x 1 ,...,x k }
The method according to any one of claims 1 to 7, wherein the decoding the first channel-coded signal according to the integrated log-likelihood ratio information to obtain a decoding result, comprising:

Determine the maximum value of the log-likelihood ratio information after air interface fusion is performed on each transmitted symbol in the transmitted symbol set X={x 1 ,...,x k };

According to the maximum value of the log-likelihood ratio information, the position sequence number of the l-th transmitted symbol in the m-th block signal corresponding to the first channel-coded signal is determined in the set X; that is:
Wherein k * is the position sequence number of the lth transmitted symbol in the mth block signal of the first channel coded signal in the transmission set X;

The decoding result obtained by determining the fusion receiver according to the position sequence number is:
in,
is represented as the transmitted symbol of the k- th position sequence number in the transmitted symbol set X.
A cooperative receiving system based on air interface information fusion, characterized in that it includes:

a transmitter, used for simultaneously sending the first channel coding signal to N cooperative receivers, where N is a set constant;

a cooperative receiver, configured to cancel the phase rotation of the channel to the first channel coded signal to obtain a second channel coded signal;

The log-likelihood ratio calculation module is used to calculate the signal-to-noise ratio of the second channel coded signal of the N cooperative receivers, and select Q from the N cooperative receivers within the range of the set signal-to-noise ratio. a cooperative receiver, calculating a log-likelihood ratio according to the second channel coded signals of the Q cooperative receivers, where Q is a positive integer, and Q≤N;

The air interface information fusion transmission module is used to arbitrarily select a cooperative receiver from the Q cooperative receivers as a fusion receiver, and combine the pairs of the remaining (Q-1) cooperative receivers by means of air interface information fusion. transmitting the digital likelihood ratio to the fusion receiver;

an information integration module, configured to control the fusion receiver to integrate the log-likelihood ratio information of the Q cooperative receivers;

a decoding module, configured to decode the first channel coded signal according to the integrated log-likelihood ratio information to obtain a decoding result;

A propagation module, configured to broadcast the decoding result to (N-1) cooperative receivers other than the fusion receiver.
The system according to claim 9, wherein the air interface information fusion transmission module comprises:

The normalization information sending module is used to multiply the normalized signal obtained by multiplying the log-likelihood ratio of the (Q-1) cooperative receivers by the normalization factor b, and repeatedly send it to the fusion receiver Z times, Z is the setting constant;

The normalization information receiving module is used for receiving the normalized signal by the fusion receiver through the normalization factor a to obtain the received signal.