CN111030795A - Transmission method for time-reversed wireless energy-carrying communication system under non-ideal channel - Google Patents

Abstract

The invention discloses a transmission method for a time-reversed wireless energy-carrying communication system under a non-ideal channel. In the method, the time-reversal characteristics are fully considered for the reliability of a multi-user multi-transmit single-receive wireless energy-carrying communication system under non-ideal channel state information. The efficiency of the system is enhanced by using the time-reversal space-time focusing characteristics, and the optimization problem is planned under the condition of non-ideal CSI through the energy-rate closed expression containing the channel estimation error. The method can improve the energy harvesting efficiency under the condition of ensuring a certain information reachability rate, and improve the reliability and effectiveness of the system compared with the traditional MISO‑SWIPT.

Description

Transmission method for time-reversed wireless energy-carrying communication system under non-ideal channel

technical field

The present invention relates to the field of communication technologies, and in particular, to a transmission method for a time-reversed wireless energy-carrying communication system under a non-ideal channel.

Background technique

With the continuous evolution of communication technology, green communication and the Internet of Everything have become the main development trends of future communication networks. Massive devices, including mobile phones, sensors, and household appliances, are connected to communication networks for functions such as remote control, data collection, and data exchange. Low-cost and low-power devices are also typical devices for future communications, and such devices will be more and more widely used in the fields of Internet of Things (Internet of Things, IoT) and Wireless Sensor Network (WSN). However, the energy required for the operation of such devices often comes from pre-charged batteries, and it is difficult to charge or replace the device batteries due to cost, size, and application scenarios. Therefore, it is a feasible and efficient solution to obtain energy from the radio frequency signal in the environment to charge each device, and at the same time realize the safe reception of information and data. This also laid the foundation for the concept of wireless energy-carrying communication.

In a Simultaneous Wireless Information and Power Transfer (SWIPT) system, an EH path is usually used for energy collection, and an ID path is used for information transmission. At present, the received RF signal power can be used for energy collection and information transmission in two ways: time allocation scheme and power division scheme. Time sharing (TS) scheme provides each path with alternate time intervals. For the radio frequency signal, the Power Splitter (PS) scheme simultaneously provides the radio frequency signal to each path according to the power split ratio.

However, the transmission schemes of the existing wireless energy-carrying communication systems are all based on the ideal channel assumption, that is, the transmitter can obtain accurate channel state information, and then realize the effective collection of energy and information by optimizing power division. However, in practice, due to the influence of channel estimation errors and other factors, and the state of the wireless channel changes from time to time, it is very difficult to extract the ideal channel state information (Channel State Information, CSI) that can fully match the channel. Therefore, there are the following problems in the current scheme: First, the influence of more realistic non-ideal channels on the SWIPT system is generally ignored; second, the existing scheme generally ignores the influence of various interferences on multi-users. This will lead to relaxation of the QoS constraints of the quality of service of the SWIPT system, so that the transmission of the SWIPT system may not achieve the expected effect.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a transmission method for a time-reversed wireless energy-carrying communication system under a non-ideal channel.

The technical scheme adopted in the present invention is:

A transmission method for a time-reversed wireless energy-carrying communication system under a non-ideal channel, comprising the following steps:

S1: the user terminal sends a sounding pilot signal to the base station;

S2: the base station estimates the channel gain of the corresponding user terminal according to the received signal;

S3: Calculate the optimal transmit power pk of the base station sending data to the _kth user terminal under the non-ideal channel by solving the first problem model, the first problem model is:

stC1:R _k ≥R _k ^*

C2:E _k ≥E _k ^*

C4: 0≤p _k ≤p _peak

且k∈{1,2…K}

and k∈{1,2…K}

表示非理想信道下第k个用户终端的信道增益，

表示第k个用户终端的天线噪声，

表示系统噪声，R_k ^*表示预先设置的第k个时隙对应的用户终端的最小信息可达速率阈值，E_k ^*表示预先设置的第k个时隙对应的用户终端的最低接收能量阈值，R_k表示第k个时隙对应的用户终端在非理想信道下的实际信息可达速率，E_k表示第k个时隙对应的用户终端在非理想信道下的实际能量值，P表示预先设置的基站的最大发射功率，

表示第k个用户终端在非理性信道下接收到的符号间干扰功率，

表示k个用户终端在非理想信道下接收到的码间干扰功率，表示通信过程中偏向信息传输的加权因子，p_peak表示每个时隙的峰值功率，0＜β＜1，R_k、E_k、

以及

均通过含有信道估计误差的表达式计算得到；Among them, P1 represents the objective function to be solved in the first problem model, C1, C2, C3, C4 and C5 represent the constraints of the objective function P1 in the first problem model, and p _k represents the base station in the kth time slot is the transmit power of sending data to the corresponding kth user terminal, α _k represents the non-negative model variable corresponding to the kth user terminal, K represents the number of user terminals,

represents the channel gain of the kth user terminal under the non-ideal channel,

represents the antenna noise of the kth user terminal,

represents the system noise, R _k ^* represents the preset minimum information reachable rate threshold of the user terminal corresponding to the k th time slot, E _k ^* represents the preset minimum receiving energy threshold of the user terminal corresponding to the k th time slot, R _k represents the actual information reachable rate of the user terminal corresponding to the kth time slot in the non-ideal channel, E _k represents the actual energy value of the user terminal corresponding to the kth time slot in the non-ideal channel, P represents the preset the maximum transmit power of the base station,

represents the intersymbol interference power received by the kth user terminal under the irrational channel,

Represents the inter-symbol interference power received by k user terminals in a non-ideal channel, represents the weighting factor biased towards information transmission in the communication process, p _peak represents the peak power of each time slot, 0<β<1, R _k , E _k ,

as well as

are calculated by expressions containing channel estimation errors;

S4: the base station sets the transmit power of the kth time slot to p _k , and sends the information data subjected to time reversal processing to the corresponding user terminal based on the transmit power;

S5: After receiving the information data, the user terminal transmits β times the signal power to the signal decoder, and transmits 1-β times the signal power to the energy collector.

Further, in step S3, the transmit power pk of the _kth time slot of the base station is calculated by converting the first problem model into a second problem model, and the second problem model is:

stC6:R _k ≥R _k ^*

C7:E _k ≥E _k ^*

C9: 0≤p _k ≤p _peak

且k∈{1,2…K}

and k∈{1,2…K}

Wherein, P2 represents the objective function to be solved in the second problem model, C6, C7, C8, C9 and C10 represent the constraints of the objective function P2 in the second problem model, q _k represents a non-negative intermediate variable, q _k =α _k p _k .

Further, in step S3, the objective function P2 is solved by using the CVX convex optimization toolbox to obtain the objective solution p _k .

Further, the user terminal is a single-antenna user terminal.

R_k以及E_k分别通过以下公式计算得到：further,

R _k and E _k are calculated by the following formulas respectively:

in,

表示第k个用户终端在非理想信道下的接收功率，

表示能量转化效率，L表示多径总条数，M表示基站的发射天线总数，ψ表示预先设置的信道误差，p'_k表示用户终端k的发射功率，

表示基站天线x与用户终端y之间的噪声功率，

表示基站天线i与用户终端j之间第r条多径的高斯白噪声，

represents the received power of the kth user terminal under the non-ideal channel,

represents the energy conversion efficiency, L represents the total number of multipaths, M represents the total number of transmit antennas of the base station, ψ represents the preset channel error, p' _k represents the transmit power of the user terminal k,

represents the noise power between the base station antenna x and the user terminal y,

represents the white Gaussian noise of the r-th multipath between the base station antenna i and the user terminal j,

表示基站天线m与基站天线m'之间的相关性矩阵，

表示用户终端k的传输天线与用户终端k'的传输天线之间的相关性矩阵，(R_U)_kk'表示用户终端k与用户终端k'之间的相关性矩阵。where, (x,y)∈{(m,l),(m',l),(m,k+1-l),(m,L+1-l)},(i,j,r) ∈{(m,k,L-1-l),(m,k,l),(m,k',l),(m',k',l')}, m,m'∈{1 ,2...M}, k,k'∈{1,2...K}, l,l'∈{1,2...L},

represents the correlation matrix between the base station antenna m and the base station antenna m',

represents the correlation matrix between the transmission antenna of the user terminal k and the transmission antenna of the user terminal k', and (R _U ) _kk' represents the correlation matrix between the user terminal k and the user terminal k'.

The transmission method of the time-reversed wireless energy-carrying communication system under the non-ideal channel provided by the present invention fully considers the influence of the time-reversal characteristics on the reliability and effectiveness of the multi-user multi-transmit single-receive wireless energy-carrying communication system under the non-ideal channel state information , the effectiveness of the system is enhanced by using the time-reversal space-time focusing characteristics, and the optimization problem is planned under the condition of non-ideal CSI through the energy-rate closed expression containing the channel estimation error. The method provided by the present invention can guarantee certain information. Compared with traditional MISO-SWIPT, the energy harvesting efficiency is improved under the condition of achievable rate, which improves the reliability and effectiveness of the system.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a schematic flowchart of a transmission method for a time-reversed wireless energy-carrying communication system under a non-ideal channel provided by the present embodiment;

2 is a system block diagram of a time-reversed wireless energy-carrying communication system provided by the present embodiment;

Figure 3 is a graph showing the relationship between SINR and SNR during the experiment. ;

Fig. 4 is the schematic diagram that the energy received by the energy collector of the user terminal varies with the transmission power of the base station during the experiment;

FIG. 5 is a schematic diagram illustrating the variation of the energy received by the energy harvester of the user terminal with the achievable information rate of the user terminal during the experiment.

Detailed ways

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, not for The invention is limited.

This embodiment provides a transmission method for a time-reversed wireless energy-carrying communication system under a non-ideal channel, as shown in FIG. 1, including the following steps:

S1: The user terminal sends a sounding pilot signal to the base station.

S2: The base station estimates the channel gain of the corresponding user terminal according to the received signal.

In order to ensure that the user terminal maximizes energy acquisition under the condition of a certain information reachability rate, a first problem model is preset.

S3: Calculate the optimal transmit power pk of the base station sending data to the _kth user terminal under the non-ideal channel by solving the first problem model. The first problem model is:

stC1:R _k ≥R _k ^*

C2:E _k ≥E _k ^*

C4: 0≤p _k ≤p _peak

且k∈{1,2…K}

and k∈{1,2…K}

表示非理想信道下第k个用户终端的信道增益，

表示第k个用户终端的天线噪声，

表示系统噪声，R_k ^*表示预先设置的第k个时隙对应的用户终端的最小信息可达速率阈值，E_k ^*表示预先设置的第k个时隙对应的用户终端的最低接收能量阈值，R_k表示第k个时隙对应的用户终端在非理想信道下的实际信息可达速率，E_k表示第k个时隙对应的用户终端在非理想信道下的实际能量值，P表示预先设置的基站的最大发射功率，

表示第k个用户终端在非理性信道下接收到的符号间干扰功率，

表示k个用户终端在非理想信道下接收到的码间干扰功率，表示通信过程中偏向信息传输的加权因子，p_peak表示每个时隙的峰值功率，0＜β＜1，R_k、E_k、

以及

均通过含有信道估计误差的表达式计算得到。Among them, P1 represents the objective function to be solved in the first problem model, C1, C2, C3, C4 and C5 represent the constraints of the objective function P1 in the first problem model, p _k represents the base station in the kth time slot corresponding to the The transmit power of data sent by k user terminals, α _k represents the non-negative model variable corresponding to the kth user terminal, K represents the number of user terminals,

represents the channel gain of the kth user terminal under the non-ideal channel,

represents the antenna noise of the kth user terminal,

represents the system noise, R _k ^* represents the preset minimum information reachable rate threshold of the user terminal corresponding to the k th time slot, E _k ^* represents the preset minimum receiving energy threshold of the user terminal corresponding to the k th time slot, R _k represents the actual information reachable rate of the user terminal corresponding to the kth time slot in the non-ideal channel, E _k represents the actual energy value of the user terminal corresponding to the kth time slot in the non-ideal channel, P represents the preset the maximum transmit power of the base station,

represents the intersymbol interference power received by the kth user terminal under the irrational channel,

Represents the inter-symbol interference power received by k user terminals in a non-ideal channel, represents the weighting factor biased towards information transmission in the communication process, p _peak represents the peak power of each time slot, 0<β<1, R _k , E _k ,

as well as

Both are calculated by expressions containing channel estimation errors.

The first problem model is a non-convex optimization problem. In the calculation process, the non-convex optimization problem can be transformed into a convex optimization problem by introducing a non-negative variable q _k to ensure its continuity, where q _k =α _k p _k (k =1,...,k), that is, in step S3, the first problem model can be transformed into a second problem model to calculate the transmit power p _k of the kth time slot of the base station, where the second problem model is :

stC6:R _k ≥R _k ^*

C7:E _k ≥E _k ^*

C9: 0≤p _k ≤p _peak

且k∈{1,2…K}

and k∈{1,2…K}

Among them, P2 represents the objective function to be solved in the second problem model, C6, C7, C8, C9 and C10 represent the constraints of the objective function P2 in the second problem model, q _k represents a non-negative intermediate variable, q _k =α _k p _k .

In step S3, the objective function P2 can be solved by the CVX convex optimization toolbox to obtain the objective solution p _k . It should be noted that step S3 in this embodiment may be performed by the base station, that is, the base station may calculate p _k , but in other embodiments, p _k may also be calculated by a specially set computing terminal, and the computing terminal After the _pk is calculated, the _pk is sent to the base station for the base station to set the transmit power.

S4: The base station sets the transmit power of the kth time slot to p _k , and sends the information data subjected to time reversal processing to the corresponding user terminal based on the transmit power.

Due to the space-time focusing characteristic of TR (Time Reversal, time inversion), the transmitted signal of the base station can gather most of the useful signal power in a very short time interval, and form a cluster at the target.

S5: After receiving the information data, the user terminal transmits β times the signal power to the signal decoder, and transmits 1-β times the signal power to the energy collector.

The user terminal in this embodiment may adopt a PS receiver.

For the system block diagram of the time-reversed wireless energy-carrying communication system provided in this embodiment, see FIG. 2 . In FIG. 2 , after receiving the TR-modulated signal power sent by the base station, the user terminal transmits the β part of the signal power. To the signal receiver (ie, the signal decoder), the 1-beta portion of the signal power is passed to the energy receiver (ie, the energy harvester).

It should be noted that, preferably, the user terminal in this embodiment is a single-antenna user terminal.

It is assumed that the transmitting end (base station) in this embodiment adopts M transmitting antennas, and the legitimate receiving end (user terminal side) adopts K receiving antennas, that is, there are K user terminals in the system, and each user terminal is a single-antenna user In the terminal, the channel impulse response (CIR) between the transmitting antenna m∈(1,M) of the transmitting end and the receiving antenna k∈(1,K) of the legitimate receiving end can be obtained by channel estimation. The CIR in this embodiment Can be written as:

和

分别是第l个抽头的振幅和延迟。CSI在时域内离散的矢量h_mk∈C^{L ×1}，特别的E[h_mk[l]]＝0，

E[·]表示信号期望。in,

and

are the amplitude and delay of the lth tap, respectively. CSI is a discrete vector h _mk ∈ ^{C L ×1} in the time domain, especially E[h _mk [l]]=0,

E[·] represents the signal expectation.

The signal received by a single-antenna user terminal can be written as:

h_mk∈C^L×1是引入系统的天线噪声

又由于h_mk是属于复数的向量集合，则对复信道h_m[l]进行复共轭和时序反转操作可以获得

因此，g_m每个抽头的值可以写作：Corresponding to the detailed explanation of each part in the above formula, where _sk and _sk' represent the symbols to be sent by the kth user and the k'th user respectively (E(|s| ² )=1). The multipath channel is modeled as a tapped delay line model, that is, it is assumed that h _mk ∈ ^{C L×1} is the channel state matrix E(|h _mk [l]| )=0,

h _mk ∈ ^{C L×1} is the antenna noise introduced into the system

And since h _mk is a vector set of complex numbers, the complex conjugation and timing inversion operations on the complex channel h _m [l] can be obtained.

Therefore, the value of each tap of g _m can be written as:

In order to achieve the target energy harvesting effect under the current non-ideal CSI conditions, the method provided in this embodiment makes use of the TR spatiotemporal focusing characteristic to make up for the technical disadvantage of SWIPT.

The wireless energy-carrying communication system provided in this embodiment is composed of a base station having M transmitting antennas and N single-antenna user terminals. In a multipath channel, the maximum length of the impulse response of each channel is L. In the information transmission stage, the sender first passes through the time inversion mirror to complete the time inversion process of the signal under non-ideal CSI conditions. The above process is analyzed as follows:

Since the real channel is an unknown parameter in practical applications, the effect of channel error estimation is modeled as follows:

和e_mk∈C^L×1分别表示估计通道和误差向量，它们相互独立分布且带有一个非负的误差因子ψ，可以发现具有以下特征：

and _emk ∈ ^{C L×1} represent the estimated channel and the error vector, respectively, which are distributed independently of each other and have a non-negative error factor ψ, which can be found to have the following characteristics:

E[|e _mk [l]| ² ]=ψE[||h _mk [l]| ² ]

表示的是含有发送功率p'_k的非理想信道TR预滤波向量，每个抽头的值定义为：Based on the TR technology of the non-ideal channel, combining the above two formulas, we can get

represents the non-ideal channel TR pre-filter vector with transmit power p' _k , and the value of each tap is defined as:

是h_mk[l]的在非理想信道条件下的共轭和时序反转操作。

is the conjugation and timing reversal operation of h _mk [l] under nonideal channel conditions.

Thus, the signal received by the kth user terminal is

The SINR expression of this system is:

The received power of each user terminal can be expressed as:

The power of ISI can be expressed as:

The power of inter-user interference can be expressed as:

The specific derivation process of SINR (Signal to Interference plus Noise Ratio, signal to interference plus noise ratio) can be obtained as follows

The method provided by this embodiment fully considers the influence of channel error on transmission, introduces channel error in the derivation process, and further derives each expression. The specific derivation of each part is as follows:

R_k以及E_k可以分别通过以下公式计算得到：Therefore, under the assumption of the multipath error channel and the correlation given above, the

R _k and E _k can be calculated by the following formulas respectively:

in,

表示第k个用户终端在非理想信道下的接收功率，

表示能量转化效率，L表示多径总条数，M表示基站的发射天线总数，ψ表示预先设置的信道误差，p'_k表示用户终端k的发射功率，

表示基站天线x与用户终端y之间的噪声功率，

表示基站天线i与用户终端j之间第r条多径的高斯白噪声，

represents the received power of the kth user terminal under the non-ideal channel,

represents the energy conversion efficiency, L represents the total number of multipaths, M represents the total number of transmit antennas of the base station, ψ represents the preset channel error, p' _k represents the transmit power of the user terminal k,

represents the noise power between the base station antenna x and the user terminal y,

represents the white Gaussian noise of the r-th multipath between the base station antenna i and the user terminal j,

表示基站天线m与基站天线m'之间的相关性矩阵，

表示用户终端k的传输天线与用户终端k'的传输天线之间的相关性矩阵，(R_U)_kk'表示用户终端k与用户终端k'之间的相关性矩阵。where, (x,y)∈{(m,l),(m',l),(m,k+1-l),(m,L+1-l)},(i,j,r) ∈{(m,k,L-1-l),(m,k,l),(m,k',l),(m',k',l')}, m,m'∈{1 ,2...M}, k,k'∈{1,2...K}, l,l'∈{1,2...L},

represents the correlation matrix between the base station antenna m and the base station antenna m',

represents the correlation matrix between the transmission antenna of the user terminal k and the transmission antenna of the user terminal k', and (R _U ) _kk' represents the correlation matrix between the user terminal k and the user terminal k'.

R_k以及E_k的计算公式都充分考虑了信道误差的影响，因此提高了系统的可靠性和有效性。above calculation

The calculation formulas of R _k and E _k fully consider the influence of the channel error, thus improving the reliability and effectiveness of the system.

In order to verify the effectiveness of the method provided in this embodiment, the theoretical derivation value of the transmission method of the TR-based wireless energy-carrying communication system under different conditions is simulated and verified, and the change trend of the system performance under these conditions is analyzed. The performance of the traditional wireless energy-carrying communication system transmission scheme is compared, and the impact of the robust scheme after adding TR and convex optimization on the system performance is studied. The parameters during the experiment are: when m=m', (R _T ) _mm' = 1, when m≠m', (R _T ) _mm' = ρ _T , ρ _T represents the mth antenna and the mth antenna 'The degree of correlation between the antennas, other common settings are the number of taps L=110, and the average transmit power of the base station p=1W.

The related experimental simulations were carried out.

Figure 3 shows the relationship between SINR and SNR under two conditions of ideal channel and non-ideal channel in the time inversion process. The channel error factor in Figure 3 is ψ=0.5, that is, the non-ideal channel in practical applications Under ideal channel conditions, the system will be weakened to a certain extent.

Fig. 4 shows the transmission method of the wireless energy-carrying communication system under the traditional ideal channel condition and the TR-based wireless portability under the non-ideal channel condition provided by the present embodiment when the correlation between the transmit antennas of the base station is 0 (the antennas are independent of each other). The simulation diagram of the transmission method of the energy communication system in the experimental process shows the schematic diagram of the energy received by the energy harvester of the user terminal changing with the transmission power of the user terminal. It can be seen from the figure that the simulation value is consistent with the theoretical value, and the verification The correctness of the theoretically derived value in this embodiment when the power division ratio β, the number of base station antennas, and the base station transmit power change. The specific change trend is as follows: when the transmission power of the base station increases, the energy received by the energy receiver of the user terminal also increases, but with the method provided in this embodiment, under any transmission power, the energy efficiency is better than the traditional The energy efficiency of the scheme confirms the effectiveness of the method provided in this example.

Figure 5 is obtained through simulation when the base station transmit antenna correlation is 0 (independent of each other), the power division ratio and the number of antennas change. There are two transmission schemes in the figure, one is the TR-based wireless energy-carrying communication system transmission method (non-ideal channel robustness method) provided in this embodiment, and the other is the traditional ideal channel wireless energy-carrying communication system Transmission method, it can be seen from the figure that when the power division ratio is small (the achievable information rate is small), the energy collected by the TR-based wireless energy-carrying communication system using the robust scheme is close to that of adding a certain number of antennas. The traditional scheme, and when the number of antennas is constant, the robust scheme can achieve greater information rate and collected energy than the traditional ideal channel wireless energy-carrying communication system transmission scheme. When the overall system performance needs to be considered from the two aspects of the achievable information rate and the collected energy, the size of the average rate-energy region in the robust scheme is close to a square box, and its area is larger than that of the traditional scheme. At this time, the system It can not only meet a certain reachable information rate, but also take into account the collection of a certain amount of energy. Compared with the traditional transmission method, the transmission method provided in this embodiment obviously improves the energy collection efficiency.

Aiming at the limitations of SWIPT-MISO power splitting and the assumption that the antennas are independent of each other, this paper combines TR with SWIPT-MISO under non-ideal channel conditions and uses a convex optimization algorithm to optimize its energy harvesting. A new TR-based SWIPT-MISO is proposed. MISO transfer method. With this method, PS receivers can be used, and the Kronecker model is introduced to derive the theoretical expression of the average rate-energy region under multipath channels, considering the correlation of the antennas. The simulation results show that when the method provided in this embodiment changes the number of transmitter antennas, the power split ratio and other conditions, the obtained theoretical value and the simulated value are always on the same curve, which verifies the derivation process of the method provided by this embodiment. In the subsequent performance comparison with the traditional SWIPT-MISO transmission scheme, it fully shows the improvement of the system performance by introducing the TR technology. This also shows from another aspect that the combination of TR and SWIPT-MISO can complement each other's advantages and achieve ideal results. The above-mentioned serial numbers of the embodiments of the present invention are only for description, and do not represent the advantages or disadvantages of the embodiments.

From the description of the above embodiments, those skilled in the art can clearly understand that the method of the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is better implementation. Based on this understanding, the technical solutions of the present invention can be embodied in the form of software products in essence or the parts that make contributions to the prior art, and the computer software products are stored in a storage medium (such as ROM/RAM, magnetic disk, CD), including several instructions to make a terminal (which may be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) execute the methods described in the various embodiments of the present invention.

The embodiments of the present invention have been described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are merely illustrative rather than restrictive. Under the inspiration of the present invention, without departing from the scope of protection of the present invention and the claims, many forms can be made, which all belong to the protection of the present invention.

Claims (5)

1. a transmission method for time inversion wireless energy-carrying communication system under a non-ideal channel, is characterized in that, comprises the steps: S1: the user terminal sends a sounding pilot signal to the base station; S2: the base station estimates the channel gain of the corresponding user terminal according to the received signal; S3: Calculate the optimal transmit power pk of the base station sending data to the _kth user terminal under the non-ideal channel by solving the first problem model, the first problem model is: P1:

stC1:R _k ≥R _k ^* C2:E _k ≥E _k ^* C3:

C4: 0≤p _k ≤p _peak C5:

and k∈{1,2…K} Among them, P1 represents the objective function to be solved in the first problem model, C1, C2, C3, C4 and C5 represent the constraints of the objective function P1 in the first problem model, and p _k represents the base station in the kth time slot is the transmit power of sending data to the corresponding kth user terminal, α _k represents the non-negative model variable corresponding to the kth user terminal, K represents the number of user terminals,

represents the channel gain of the kth user terminal under the non-ideal channel,

represents the antenna noise of the kth user terminal,

represents the system noise, R _k ^* represents the preset minimum information reachable rate threshold of the user terminal corresponding to the k th time slot, E _k ^* represents the preset minimum receiving energy threshold of the user terminal corresponding to the k th time slot, R _k represents the actual information reachable rate of the user terminal corresponding to the kth time slot in the non-ideal channel, E _k represents the actual energy value of the user terminal corresponding to the kth time slot in the non-ideal channel, P represents the preset the maximum transmit power of the base station,

represents the intersymbol interference power received by the kth user terminal under the irrational channel,

Represents the inter-symbol interference power received by k user terminals in a non-ideal channel, represents the weighting factor biased towards information transmission in the communication process, p _peak represents the peak power of each time slot, 0<β<1, R _k , E _k ,

as well as

are calculated by expressions containing channel estimation errors; S4: the base station sets the transmit power of the kth time slot to p _k , and sends the information data subjected to time reversal processing to the corresponding user terminal based on the transmit power; S5: After receiving the information data, the user terminal transmits β times the signal power to the signal decoder, and transmits 1-β times the signal power to the energy collector. 2. The transmission method of the time-reversed wireless energy-carrying communication system under a non-ideal channel as claimed in claim 1, wherein in step S3, the first problem model is converted into the second problem model to calculate the first problem of the base station. The transmit power pk of _k time slots, the second problem model is: P2:

stC6:R _k ≥R _k ^* C7:E _k ≥E _k ^* C8:

C9: 0≤p _k ≤p _peak C10:

and k∈{1,2…K} Wherein, P2 represents the objective function to be solved in the second problem model, C6, C7, C8, C9 and C10 represent the constraints of the objective function P2 in the second problem model, q _k represents a non-negative intermediate variable, q _k =α _k p _k . 3. The transmission method of the time-reversed wireless energy-carrying communication system under a non-ideal channel as claimed in claim 2, wherein in step S3, the objective function P2 is obtained by solving the objective function P2 through the CVX convex optimization toolbox to obtain the objective solution p _k . 4 . The transmission method for a time-reversed wireless energy-carrying communication system under a non-ideal channel according to claim 1 , wherein the user terminal is a single-antenna user terminal. 5 . 5. The transmission method of the time-reversed wireless energy-carrying communication system under a non-ideal channel according to any one of claims 1-4, wherein,

R _k and E _k are calculated by the following formulas respectively:

in,

represents the received power of the kth user terminal under the non-ideal channel,

represents the energy conversion efficiency, L represents the total number of multipaths, M represents the total number of transmit antennas of the base station, ψ represents the preset channel error, p' _k represents the transmit power of the user terminal k,

represents the noise power between the base station antenna x and the user terminal y,

represents the white Gaussian noise of the r-th multipath between the base station antenna i and the user terminal j, where, (x,y)∈{(m,l),(m',l),(m,k+1-l),(m,L+1-l)},(i,j,r) ∈{(m,k,L-1-l),(m,k,l),(m,k',l),(m',k',l')}, m,m'∈{1 ,2...M}, k,k'∈{1,2...K}, l,l'∈{1,2...L},

represents the correlation matrix between the base station antenna m and the base station antenna m',

represents the correlation matrix between the transmission antenna of the user terminal k and the transmission antenna of the user terminal k', and (R _U ) _kk' represents the correlation matrix between the user terminal k and the user terminal k'.

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