Distributed energy synthesis cluster communication method based on reverse measurement

Abstract

The invention provides a distributed energy synthesis trunking communication method based on reverse measurement. The distributed energy synthesis trunking communication method comprises the following steps: any terminal of a receiving cluster sends a training signal to each terminal of a transmitting cluster; each terminal of the transmitting cluster receives the training signal and performs channel estimation according to the received training signal to obtain channel information between the transmitting cluster and the receiving cluster; the terminals of the transmitting cluster pre-compensate the transmitting signals according to the channel information and then transmit the transmitting signals to the terminals of the receiving cluster; and each terminal of the receiving cluster performs iterative combination according to the received signal to complete distributed energy synthesis cluster communication. By applying the technical scheme of the invention, the technical problems of insufficient communication distance and high implementation difficulty of the distributed energy synthesis trunking communication method in the prior art can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of trunking communication, and in particular, to a distributed energy synthesis trunking communication method based on reverse measurement. Background Art

[0002] Traditional means to improve trunking communication usually increase the transmission power of the RF front-end to exchange power for communication distance, or adopt the relay communication method to continuously receive and forward the transmitted signal through a relay system to complete the relay transmission of the signal. Increasing the transmission power will bring an increase in the size of the communication terminal, increasing the requirements for the payload. While adopting relay communication requires an additional relay terminal for data aggregation, and once damage or interference occurs, the communication link will be interrupted.

[0003] In recent years, a long-distance trunking communication method through distributed energy synthesis has been proposed. This method mainly studies how to effectively converge the transmitted signals of scattered terminals at the target point to achieve positive superposition of energy. However, currently, to implement distributed energy synthesis trunking communication, extremely high requirements are imposed on the system accuracy, and extremely high time synchronization accuracy, beam pointing accuracy, and ranging accuracy need to be ensured. This is also the main factor restricting the practical application of this technology. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] The present invention provides a distributed energy synthesis trunking communication method based on reverse measurement. The distributed energy synthesis trunking communication method includes: receiving training signals sent by any terminal of the receiving trunking to each terminal of the transmitting trunking; each terminal of the transmitting trunking receives the training signals and performs channel estimation according to the received training signals to obtain channel information between the transmitting trunking and the receiving trunking; each terminal of the transmitting trunking pre-compensates the transmitted signal according to the channel information and then transmits it to each terminal of the receiving trunking; each terminal of the receiving trunking performs iterative merging according to the received signals to complete distributed energy synthesis trunking communication.

[0006] Further, the training signals that can be transmitted over a long distance are periodically broadcast by the receiving terminal, or first, a long-distance signal transmission application is sent by the transmitting terminal, and then the training signals are sent by the receiving terminal.

[0007] Further, the channel information includes the amplitude and phase changes caused by the channel itself, and the time delay information introduced by the distance difference between the transmitting and receiving parties.

[0008] Further, the pre-compensation specifically includes: obtaining the steering vector W of the transmitted signal according to the channel information, is the channel phase of the nth channel, where n = 1, 2, … N, and N is the number of terminals in the transmitting cluster; according to S = WX, the signal S after beamforming with pre-compensation for the transmitting cluster terminals is obtained, and X = [X1, X2, … X n , …, X N T is the transmitted signal, and X n is the transmitted signal of the nth terminal in the transmitting cluster.

[0009] Furthermore, the iterative combining includes: first, using an iterative algorithm to perform weighted delay on the signals of each received cluster terminal, and then using a diversity combining algorithm to perform signal combining and receiving on the signals of each received cluster terminal after the weighted delay processing.

[0010] Furthermore, the iterative algorithm uses the SUMPLE algorithm.

[0011] Furthermore, the diversity combining algorithm uses the maximum ratio combining algorithm.

[0012] Applying the technical solution of the present invention provides a distributed energy synthesis cluster communication method based on reverse measurement. This distributed energy synthesis cluster communication method uses reverse measurement means, enabling the transmitting end cluster to estimate the channel state information and path delay through reverse training. Through the reciprocity of the channel, pre-compensation processing is completed at the transmitting end to achieve effective synthesis of signals at the receiving end. The communication method of the present invention does not need to measure the distance between transmitting terminals or from each transmitting terminal to the target node anymore, but estimates parameters through reverse training signals to perform equivalent distance difference compensation, thereby achieving effective energy superposition and effectively improving the signal-to-noise ratio gain. Compared with the prior art, the technical solution of the present invention can solve the technical problems of insufficient communication distance and high implementation difficulty in the distributed energy synthesis cluster communication method in the prior art. Description of the Drawings

[0013] The included drawings are used to provide a further understanding of the embodiments of the present invention. They form a part of the specification, are used to illustrate the embodiments of the present invention, and are used together with the text description to explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0014] Figure 1 Shows a schematic model diagram of a distributed energy synthesis cluster provided according to a specific embodiment of the present invention;

[0015] Figure 2 Shows a schematic diagram of reverse measurement provided according to a specific embodiment of the present invention;

[0016] ​Figure 3 The figure shows a schematic diagram of an iterative merging algorithm provided according to a specific embodiment of the present invention. Detailed implementation manners

[0017] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0018] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0019] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters indicate similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0020] According to a specific embodiment of the present invention, a distributed energy synthesis cluster communication method based on reverse measurement is provided. The distributed energy synthesis cluster communication method includes:

[0021] Receiving training signals sent by any terminal in the receiving cluster to each terminal in the transmitting cluster;

[0022] Each terminal in the transmitting cluster receives the training signals and performs channel estimation according to the received training signals to obtain channel information between the transmitting cluster and the receiving cluster;

[0023] Each terminal in the transmitting cluster pre - compensates the transmitted signal according to each channel information and then transmits it to each terminal in the receiving cluster;

[0024] Each terminal in the receiving cluster performs iterative combining according to the received signal to complete distributed energy - combining cluster communication.

[0025] Applying this configuration method provides a distributed energy - combining cluster communication method based on reverse measurement. This distributed energy - combining cluster communication method uses reverse measurement means, enabling the transmitting - end cluster to estimate the channel state information and path delay through reverse training. Through the reciprocity of the channel, pre - compensation processing is completed at the transmitting end to achieve effective signal synthesis at the receiving end. The communication method of the present invention does not need to measure the distance between transmitting terminals or from each transmitting terminal to the target node anymore. Instead, parameter estimation is performed through reverse training signals for equivalent distance - difference compensation, thereby achieving effective energy superposition and effectively improving the signal - to - noise ratio gain.

[0026] Further, in the present invention, first, any terminal in the receiving cluster sends a training signal to each terminal in the transmitting cluster.

[0027] As a specific embodiment of the present invention, as Figure 1 shown, for a transmitting cluster including N terminals and a receiving cluster including M terminals, the reverse - measurement schematic diagram is as shown in the appendix Figure 2 shown.

[0028] In this embodiment, let the training signal reversely sent by the m - th terminal in the receiving cluster be y′ m , then the training signal X′ received by the transmitting cluster can be expressed as X′ = H′y′ m +R, where X′ = [X′1,X′2,…X′ n ,…X′ N T , X′ n =H′ n y′ m +R n , X′ n is the training signal received by the n - th terminal in the transmitting cluster, H′ is the reverse multiplicative channel vector, H′ = [H′1,H′2,…H′ n ,…H′ N T , H′ n is the n - th reverse multiplicative channel information, R is the AWGN additive channel vector, R n is the n - th additive channel parameter, n = 1,2,…N, m = 1,2,…M.

[0029] ​​In the present invention, the receiving end can periodically broadcast low-speed information that can be transmitted over a long distance, or first send a long-distance signal transmission application from the transmitting end, and then the receiving end sends low-speed information, so as to realize that the receiving end cluster first sends low-speed training signals.

[0030] Further, after the receiving cluster sends training signals to each terminal of the transmitting cluster, the transmitting cluster performs channel estimation based on the received training signals to obtain channel state information. In the present invention, on the one hand, the channel state information includes the amplitude and phase changes caused by the channel itself, and on the other hand, it also includes the time delay information introduced by the distance difference between the transmitting and receiving parties.

[0031] As a specific embodiment of the present invention, it can be used to represent the channel estimation result, wherein, is the transmission amplitude of the nth channel, is the channel phase of the nth channel, is the time delay error introduced by the distance, is the time delay error introduced by the terminal system itself, is the phase error introduced by the change of channel characteristics. In the case where the channel changes slowly approximately, the phase error introduced by the change of channel characteristics can be ignored, then

[0032] After completing the channel parameter estimation, the reverse measurement process ends. So far, before the energy synthesis transmission at the cluster transmitting end, the prior information of the channel state has been obtained, so that the preprocessing of the transmitted signal can be completed at the transmitting end, which greatly simplifies the steps and process of traditional energy synthesis.

[0033] Further, in the present invention, after obtaining the channel information, each terminal of the transmitting cluster pre-compensates the transmitted signal according to each channel information and then transmits it to each terminal of the receiving cluster.

[0034] Under the condition that the channel state information changes smoothly, the estimated channel state information can be used for preprocessing, that is, pre-compensating the channel information and time delay information in advance, so as to ensure that after the cluster transmitting beam is preprocessed, the receiving end can receive the synthesized signal after distance compensation.

[0035] To enable the transmitted signal to be effectively superimposed at the receiving end, it is necessary to effectively compensate the phase of the signal at the transmitting end. As a specific embodiment of the present invention, pre-compensating the transmitted signal mainly includes compensating the wave path difference introduced by the different distances from each terminal of the transmitting cluster to the target position, and compensating the time delay difference Compensation is carried out.

[0036] According to the estimated channel information, assuming that the transmitting antenna powers are the same and only focusing on the influence brought by the phase, first for the transmitted signal X = [X1, X2, … X n , … X N T obtain the steering vector W, then the signal after pre-compensation and beamforming of the transmitting cluster terminals is S = WX. Among them, x n (t) is the original transmitted data of the nth transmitting terminal, t is the time, A n is the amplitude of the transmitted signal of the nth terminal, ω0 is the frequency of the transmitted signal, and φ0 is the initial phase of the transmitted signal. The terminals in the system have the same design. Assuming that the influence on the signal amplitude during the signal processing is not significant, it can be approximately considered that the transmitted amplitudes A n of each signal are a constant A, then there is A n = A.

[0037] Furthermore, in the present invention, each terminal in the receiving cluster performs iterative combining according to the received signal to complete communication.

[0038] As a specific embodiment of the present invention, after the signal S is transmitted through the channel, the combined energy signal received by the receiving cluster is Y = HWX + Q, Y = [Y1, Y2, … Y m , … Y M T , Q is the Gaussian white noise signal, H is the forward multiplicative channel vector. At this time, when the transceiver time is short enough, the forward and reverse multiplicative channel vectors change slowly and can be approximately considered unchanged here, H≈H′. Normalize and simplify the above combined energy, and the combined energy signal received by the mth terminal in the receiving cluster is Among them, Y m is the combined energy signal received by the mth receiver terminal; θ Δ is the phase estimation error. When the phase estimation error θ Δ is small enough, it can be considered that the signal obtains energy superposition; τ m is the time delay difference existing in the mth terminal of the receiving cluster.

[0039] Although there is still a time delay difference τ m among the cluster terminals in the receiving cluster due to the different relative positions of the receiving cluster terminals, each terminal in the receiving cluster can already completely receive the energy superposition signal of the transmitting cluster terminal, and the amplitude obtains an N-fold gain and the energy obtains an N 2 -fold gain.

[0040] ​​For the receiving cluster, the receiving end aggregation node needs to concentrate the received signals again, which is equivalent to performing a signal combination on each receiving terminal. However, since the formations of the terminals in the receiving cluster are different, the paths from them to the aggregation node are also different. To address this, the present invention adopts a method of secondary weighting. First, through an iterative algorithm, the signals of the terminals in each receiving cluster are weighted and delayed to solve the problem of delay error estimation and compensation caused by the path difference. Then, since the signal-to-noise ratios of the received signals are different, the present invention uses a diversity combination method to perform signal combination reception on the signals of the terminals in each receiving cluster after weighted delay processing, thus solving the problem of data reliability introduced by the different signal-to-noise ratios of each receiving terminal.

[0041] As a specific embodiment of the present invention, in the iterative algorithm, the SUMPLE algorithm, which can effectively handle the low signal-to-noise ratio environment, is adopted. One path of the main node is selected as the reference signal, and weighted iterative calculations are performed on the other paths of signals, so that the finally compensated phase error approaches the true compensation value as the number of iterations increases, thereby solving the phase error caused by the relative position error and completing the signal combination of multiple receiving antennas.

[0042] The SUMPLE algorithm is improved from the classic SIMPLE algorithm. Although its computational complexity is slightly higher than that of the SIMPLE algorithm, it still shows a proportional relationship with the number of antennas and can effectively synthesize weak signals.

[0043] Furthermore, considering that the signal-to-noise ratios of the signals received by the terminals in each receiving cluster are different, when performing signal combination, a combination algorithm is adopted to complete the secondary weighting of the signals. As a specific embodiment of the present invention, after estimating the signal-to-noise ratio of the received signals, the classic Maximum Ratio Combing (MRC) algorithm is used, and the combination weight is iteratively optimized with the maximization of the combined signal-to-noise ratio as the combination criterion.

[0044] The conditions for the terminals in the receiving cluster to perform iterative combination based on the received signals include:

[0045] (1) Each terminal in the receiving cluster is within the range of the distributed transmitting main beam;

[0046] (2) The transmitting cluster and the receiving cluster satisfy D r D t < kλR, where D t is the aperture size of the transmitting cluster, D r is the aperture size of the receiving cluster, k is the wave number, λ is the wavelength of the electromagnetic wave, and R is the transmission and reception distance.

[0047] In this way, an M-fold signal-to-noise ratio gain is obtained again at the aggregation node. So far, the distributed energy synthesis system of the present invention has obtained a total of N 2An M-fold signal-to-noise ratio gain, which also means that the communication distance between the transceiver clusters has been greatly improved.

[0048] The communication method of the present invention does not need to measure the distance between the transmitting terminals or the distance from each transmitting terminal to the target node anymore. Instead, parameter estimation is performed through the reverse training signal to perform equivalent distance difference compensation, so as to achieve effective energy superposition and effectively improve the signal-to-noise ratio gain. At the same time, since the distributed energy synthesis communication uses the energy superposition of each transmitting terminal, the damage of a small number of transmitting terminals only partially affects the energy synthesis effect of the transmitting cluster at the receiving terminal, causing a partial reduction in energy, rather than causing the terminals of the entire communication link, greatly improving the anti-damage ability of the cluster communication.

[0049] In summary, the present invention provides a distributed energy synthesis cluster communication method based on reverse measurement. The distributed energy synthesis cluster communication method uses the means of reverse measurement to enable the transmitting end cluster to estimate the channel state information and path delay through the method of reverse training, and through the reciprocity of the channel, pre-compensation processing is completed at the transmitting end to achieve effective synthesis of signals at the receiving end.

[0050] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A distributed energy synthesis cluster communication method based on reverse measurement, characterized in that, The described distributed energy synthesis cluster communication method includes: Receiving training signals sent by any terminal of the receiving cluster to each terminal of the transmitting cluster; Each terminal of the transmitting cluster receives the training signals and performs channel estimation based on the received training signals to obtain channel information between the transmitting cluster and the receiving cluster; Each terminal of the transmitting cluster pre-compensates the transmitted signals according to the channel information and then transmits them to each terminal of the receiving cluster; Each terminal of the receiving cluster performs iterative combining on the received signals to complete distributed energy synthesis cluster communication.

2. The distributed energy synthesis cluster communication method based on reverse measurement according to claim 1, characterized in that, The training signals that can be transmitted over a long distance are broadcast periodically by the receiving terminal, or the transmitting terminal first sends a long-distance signal transmission request, and then the receiving terminal sends the training signals.

3. The distributed energy synthesis cluster communication method based on reverse measurement according to claim 1 or 2, characterized in that, The channel information includes the amplitude and phase changes caused by the channel itself, as well as the delay information introduced by the distance difference between the transmitter and the receiver.

4. The distributed energy synthesis cluster communication method based on reverse measurement according to claims 1 to 3, characterized in that, The pre-compensation specifically includes: Obtain the steering vector W of the transmitted signal according to the channel information, is the channel phase of the nth channel, n = 1, 2, … N, and N is the number of terminals in the transmitting cluster; Obtain the signal S after beamforming with pre-compensation for the transmitting cluster terminals according to S = WX, where X = [X1, X2, … X n , …, X N T is the transmitted signal, and X n is the transmitted signal of the nth terminal in the transmitting cluster.​ 5. The distributed energy synthesis cluster communication method based on reverse measurement according to claim 1, characterized in that, The iterative combining includes: first, weighting and delaying the signals of each receiving cluster terminal using an iterative algorithm, and then performing signal combining and receiving on the signals of each receiving cluster terminal after the weighting and delaying process using a diversity combining algorithm.

6. The distributed energy synthesis cluster communication method based on reverse measurement according to claim 5, characterized in that, The iterative algorithm uses the SUMPLE algorithm.

7. The distributed energy synthesis cluster communication method based on reverse measurement according to claim 5, characterized in that, The diversity combining algorithm uses the maximum ratio combining algorithm.

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