Wireless communication method based on OFDM (Orthogonal Frequency Division Multiplexing) and related device

Abstract

The invention discloses an OFDM (Orthogonal Frequency Division Multiplexing)-based wireless communication method and a related device, and the method comprises the steps: constructing a system energy efficiency optimization problem by taking the minimum system energy efficiency as a target on the premise of guaranteeing the system information rate and the communication quality; solving the system energy efficiency optimization problem to obtain a first-stage power optimal allocation strategy and a second-stage power optimal allocation strategy; according to the optimal power allocation strategy at the first stage and the optimal power allocation strategy at the second stage, wireless communication is carried out by adopting a wireless energy-carrying communication technology, and the method and the related device can solve the problem of low system energy efficiency in the wireless energy-carrying communication technology.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology and relates to a wireless communication method and related devices based on OFDM. Background Technology

[0002] In recent years, with the rapid development of IoT technology, the interconnection of everything is gradually becoming a reality. The number of IoT nodes, such as sensors and other wireless access devices, has exploded. While facilitating human production and daily life, this has also led to a surge in system energy consumption. Furthermore, these wireless access devices rely on internal batteries for power, and the limited battery capacity restricts the lifespan of IoT nodes. Therefore, reducing system energy consumption and addressing the energy constraints of wireless access devices has become an urgent problem. Radio frequency (RF) energy harvesting can convert collected RF signals into electrical energy, thereby enabling wireless energy transmission. Utilizing the characteristic that RF signals can carry energy while transmitting information, wireless energy-carrying communication technology has been proposed by researchers. This technology can harvest energy while demodulating information, and the harvested energy can power the system, thus improving system energy efficiency and solving the energy constraints of wireless access devices. However, it also suffers from reduced system energy efficiency. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an OFDM-based wireless communication method and related apparatus, which can solve the problem of low system energy efficiency in wireless energy-carrying communication technology.

[0004] To achieve the above objectives, this invention discloses an OFDM-based wireless communication method, comprising: Under the premise of ensuring system information rate and communication quality, and with the goal of minimizing system energy efficiency, a system energy efficiency optimization problem is constructed. Solving the energy efficiency optimization problem of the system yields the optimal power allocation strategy for the first stage. and the optimal power allocation strategy in the second stage ; According to the first-stage optimal power allocation strategy and the optimal power allocation strategy in the second stage Wireless communication is achieved using wireless power-carrying communication technology.

[0005] Furthermore, the system energy efficiency optimization problem is as follows:

[0006]

[0007]

[0008]

[0009]

[0010]

[0011] (10) in, Indicates system energy efficiency. This represents the power allocated on the i-th subcarrier in the second phase. This represents the signal-to-interference-plus-noise ratio (SIR) at the receiver of the i-th subcarrier in the second stage. This indicates the energy conversion efficiency of the PS receiver at the relay node. This represents the path loss factor between the transmitter and the relay node. This represents the power allocated on the i-th subcarrier in the first phase. This represents the signal-to-interference-plus-noise ratio (SINR) at the receiver of the i-th subcarrier in the first stage, where n is the number of subcarriers and W is the subcarrier bandwidth. This is the power division factor.

[0012] Furthermore, the system energy efficiency for: (9) in, The total power consumption of the system, This represents the total information transmission rate in the communication system.

[0013] Furthermore, the total power consumption of the system for: (8).

[0014] Furthermore, the total information transmission rate in the communication system for: (7).

[0015] Furthermore, the information reception rate of the relay node Represented as: (1).

[0016] Furthermore, the information reception rate at the receiver end for: (4).

[0017] This invention discloses an OFDM-based wireless communication system, including... The module is used to construct a system energy efficiency optimization problem with the goal of minimizing system energy efficiency, while ensuring system information rate and communication quality. The solution module is used to solve the system energy efficiency optimization problem and obtain the first-stage optimal power allocation strategy. and the optimal power allocation strategy in the second stage ; The communication module is used to implement the first-stage power optimal allocation strategy. and the optimal power allocation strategy in the second stage Wireless communication is achieved using wireless power-carrying communication technology.

[0018] The present invention discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the OFDM-based wireless communication method.

[0019] The present invention discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the OFDM-based wireless communication method.

[0020] The present invention has the following beneficial effects: In practical operation, the OFDM-based wireless communication method and related devices described in this invention, while ensuring system information rate and communication quality, aim at minimizing system energy efficiency, construct a system energy efficiency optimization problem, solve the system energy efficiency optimization problem, and obtain the first-stage optimal power allocation strategy. and the optimal power allocation strategy in the second stage This solves the problem of low system energy efficiency in wireless power-carrying communication technology. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a diagram of the relay cooperative transmission time slot model in this invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this invention generally indicates that the preceding and following objects have an "or" relationship.

[0027] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0028] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0030] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0031] Example 1 refer to Figure 1 and Figure 2 The OFDM-based wireless communication method of the present invention includes the following steps: An OFDM wireless communication system includes a transmitter, a relay node, and a receiver. The relay node includes a receiving antenna, a power divider, an energy harvester, and a demodulator. The transmitter is equipped with a transmitting antenna, and the receiver is equipped with a receiving antenna. The receiving antenna of the relay node is connected to the transmitting antenna of the transmitter, and the receiving antenna of the receiver is connected to the transmitting antenna of the relay node. The transmission process of this system is generally divided into two stages. In the first stage, the relay node uses wireless power-carrying communication technology to simultaneously demodulate the signal sent by the transmitter and harvest energy. When the relay node receives the signal sent from the transmitter, it receives a signal with a mean of 0 and a variance of... In addition to the effects of additive white Gaussian noise, relay nodes also receive interference signals in the same frequency band, with a variance of... Power divider according to , The power split ratio divides the signal into two power streams (0 < 0). <1), and then sent to the energy harvester and the information demodulator for processing respectively. During signal processing, the information demodulator generates a signal with a mean of 0 and a variance of . The noise is defined as the ratio of the interference signal to the noise processed by this signal, which is called the interference-to-noise ratio (INR). In the second stage, the relay node uses the energy collected in the first stage to decode and forward the information to the receiver. Assume that at the receiving end, the receiver will also receive a signal with a variance of... Co-channel interference signal, mean 0, variance is Additive white Gaussian noise and the noise generated during signal processing have a mean of 0 and a variance of 0. Signal processing noise. Furthermore, the total bandwidth of the OFDM system is B Hz, the number of subcarriers is n, and the subcarrier bandwidth is W. It is assumed that the downlink channel gain can be obtained through feedback.

[0032] like Figure 2 As shown, the total transmission period in this invention is T, and the first and second stages are equal, both being T / 2. Specifically, in the first stage, the relay node divides the received signal into two power streams according to a preset power division ratio, and then sends them to the information demodulator and energy harvester for information demodulation and energy harvesting, respectively. Then, in the second stage, the relay node uses the energy collected in the first stage to forward the demodulated information to the receiver.

[0033] In the first phase, relay nodes utilize wireless power-carrying communication technology for information demodulation and energy harvesting. First, consider the information rate; the information reception rate of the relay nodes... Represented as: (1) in, This indicates the transmitter's power allocation strategy in the first phase. This represents the power allocated on the i-th subcarrier in the first phase. Represents the signal-to-interference-plus-noise ratio (SIR) at the receiver of the i-th subcarrier in the first stage, where, (2) in, This represents the path loss factor between the transmitter and the relay node, as well as the energy collected by the relay node. Represented as: (3) Equation (3) indicates that the relay node can harvest energy from transmitter signals, co-channel interference signals, and noise signals, where, (0 < <1) indicates the energy conversion efficiency of the PS receiver at the relay node.

[0034] In the second phase, the relay nodes utilize the energy collected by the relay nodes in the first phase. The information is decoded and forwarded to the receiver. Based on Shannon's channel capacity formula, the information reception rate at the receiver is... Represented as: (4) in, This indicates the transmitter's power allocation strategy in the second phase. This represents the power allocated on the i-th subcarrier in the second phase. This represents the signal-to-interference-plus-noise ratio (SIR) at the receiver of the i-th subcarrier in the second stage, where... (5) in, This represents the path loss factor between the relay node and the receiver.

[0035] The achievable rate of the system from the transmitter to the receiver is the smaller of the rates obtained in the two stages. The achievable rate Represented as: (6) For ease of mathematical calculation, equation (6) is transformed to show the total information transmission rate in this communication system. for: (7) The total system power consumption includes the sum of the energy consumption in the first and second stages. The first stage includes the sum of subcarrier power consumption from the transmitter to the relay node, and the second stage includes the sum of carrier power consumption from the relay node to the receiver. Additionally, the total system power consumption includes fixed system power consumption. The energy collected by the relay node in the first stage can power the system, thereby improving system energy efficiency. In summary, the total system power consumption is obtained. for: (8) Based on the above analysis, the system information transmission rate and total system power consumption were obtained. According to the definition of energy efficiency, which is the ratio of the system's total information rate to its energy consumption, the system energy efficiency is obtained. The expression is: (9) Optimizing system energy efficiency presupposes ensuring communication quality; that is, minimizing system energy consumption while meeting a minimum information rate and guaranteeing communication quality. Before optimizing the objective, several constraints of the system must be satisfied. Therefore, the system energy efficiency optimization problem can be described as follows:

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[0037]

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[0039]

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[0041] (10) Among these constraints, C1 and C2 indicate that, from the perspective of system information rate, the system information rate should meet the minimum system information rate requirement to ensure communication quality. Constraint C3 indicates that the energy collected by the relay node in the first stage must be greater than or equal to the energy consumed in forwarding information to the receiver in the second stage; that is, the energy for information forwarding in the second stage comes from the energy collected by the relay node in the first stage. Constraint C4 indicates that the system's power consumption should be less than or equal to the system's total power limit. The system's power consumption includes the signal transmission power in the first stage and the fixed power loss of the circuit. Indicates the total power limit of the system. This represents the fixed power loss of the circuit. Constraints C5 and C6 represent the limitations on signal power and power division factor, respectively.

[0042] Similar to the method used in equation (8), a parameter q is introduced to transform the original fractional objective function into an equivalent subtractive objective function, making it easier to solve. Both have the same optimal solution. Therefore, the OP1 problem can be transformed into the following equivalent problem:

[0043] (11) OP2 remains a nonconvex optimization problem. However, when the number of subcarriers in the system is sufficiently large and the time-division conditions are met, the problem can be solved by Lagrange dual decomposition. To obtain the maximum energy efficiency of the system, the Lagrange dual method and the Dinkelbach method can be used. The Lagrange equation for OP2 is:

[0044]

[0045]

[0046] (12) The Lagrange dual function of OP2 is: (13) Since the variables are nonnegative dual variables, the original expression can be transformed into the following problem:

[0047] (14) The subgradients of each dual variable are as follows: (15) (16) (17) (18) Optimal dual variable Iterative updates obtained through the ellipsoid method Together they form the subgradient vector.

[0048] The problem is divided into an inner maximization problem and an outer minimization problem using Lagrange dual decomposition. The inner maximization problem, with the help of the given Lagrange multipliers in the outer layer, addresses the power segmentation ratio... Given before each iteration The value for power , The optimal values ​​are then obtained through the KKT conditions; while the minimization problem of the outer layer mainly relies on the Lagrange multiplier update solution, thus realizing a complete algorithm iteration.

[0049] First, to solve the optimal power allocation strategy for the first stage. Rewrite equation (12) above only with Relevant formulas:

[0050] (19) In equation (19), for Taking the partial derivative, we get: (20) Using the KKT conditions, we make equation (20) equal to 0, and obtain the optimal subcarrier power allocation in the first stage as follows: *for: (twenty one) (twenty two) This yields the optimal power allocation on the subcarriers in the first stage.

[0051] Similarly, to solve for the optimal power allocation strategy in the second stage... Rewrite equation (12) only with Relevant formulas:

[0052] (twenty three) In equation (23) Taking the partial derivative, we get: (twenty four) Using the KKT conditions, we can make equation (24) equal to 0 and obtain the optimal subcarrier power in the second stage. *for: (25) in, (26) This yields the optimal power allocation strategy on the subcarriers in the second stage.

[0053] Thus, the optimal subcarrier power allocation strategy for the transmitter to the relay node in the first stage and the optimal subcarrier power allocation strategy for the relay node to the receiver in the second stage are obtained, given before each iteration. Finding the value of completes the solution to the inner maximization problem.

[0054] Example 2 The OFDM-based wireless communication system of the present invention includes The module is used to construct a system energy efficiency optimization problem with the goal of minimizing system energy efficiency, while ensuring system information rate and communication quality. The solution module is used to solve the system energy efficiency optimization problem and obtain the first-stage optimal power allocation strategy. and the optimal power allocation strategy in the second stage ; The communication module is used to implement the first-stage power optimal allocation strategy. and the optimal power allocation strategy in the second stage Wireless communication is achieved using wireless power-carrying communication technology.

[0055] The module division in this embodiment is illustrative and represents only one logical functional division. In actual implementation, other division methods may be used. Furthermore, the functional modules in each embodiment of this application can be integrated into a single processor, exist as separate physical entities, or be integrated into a single module. The integrated modules described above can be implemented in hardware or as software functional modules.

[0056] Example 3 A computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the OFDM-based wireless communication method, for example including: constructing a system energy efficiency optimization problem with the objective of minimizing system energy efficiency while ensuring system information rate and communication quality; solving the system energy efficiency optimization problem to obtain a first-stage optimal power allocation strategy. and the optimal power allocation strategy in the second stage According to the first-stage optimal power allocation strategy and the optimal power allocation strategy in the second stage Wireless communication is achieved using wireless power-carrying communication technology. The memory may include main memory, such as high-speed random access memory (RAM), or non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which can be an industry-standard architecture bus, a peripheral component interconnection standard bus, or an extended industry-standard architecture bus. The bus can be categorized as an address bus, data bus, and control bus. The memory stores programs; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.

[0057] Example 4 A computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the OFDM-based wireless communication method, for example including: constructing a system energy efficiency optimization problem with the objective of minimizing system energy efficiency while ensuring system information rate and communication quality; solving the system energy efficiency optimization problem to obtain a first-stage optimal power allocation strategy. and the optimal power allocation strategy in the second stage According to the first-stage optimal power allocation strategy and the optimal power allocation strategy in the second stage Wireless communication is achieved using wireless power-carrying communication technology. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include random access memory (RAM) and / or cache memory, etc. The non-volatile memory may include read-only memory (ROM), hard disk, flash memory, optical disk, magnetic disk, etc.

[0058] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0059] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0060] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0061] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0062] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and disclosure of the invention. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0063] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

[0064] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A wireless communication method based on OFDM, characterized in that, include: Under the premise of ensuring system information rate and communication quality, and with the goal of minimizing system energy efficiency, a system energy efficiency optimization problem is constructed. Solving the energy efficiency optimization problem of the system yields the optimal power allocation strategy for the first stage. and the optimal power allocation strategy in the second stage ; According to the first-stage optimal power allocation strategy and the optimal power allocation strategy in the second stage Wireless communication is achieved using wireless power-carrying communication technology.

2. The OFDM-based wireless communication method according to claim 1, characterized in that, The system energy efficiency optimization problem is as follows: （10） in, Indicates system energy efficiency. This represents the power allocated on the i-th subcarrier in the second phase. This represents the signal-to-interference-plus-noise ratio (SIR) at the receiver of the i-th subcarrier in the second stage. This indicates the energy conversion efficiency of the PS receiver at the relay node. This represents the path loss factor between the transmitter and the relay node. This represents the power allocated on the i-th subcarrier in the first phase. This represents the signal-to-interference-plus-noise ratio (SINR) at the receiver of the i-th subcarrier in the first stage, where n is the number of subcarriers and W is the subcarrier bandwidth. This is the power division factor.

3. The OFDM-based wireless communication method according to claim 2, characterized in that, The system energy efficiency for: （9） in, The total power consumption of the system, This represents the total information transmission rate in the communication system.

4. The OFDM-based wireless communication method according to claim 3, characterized in that, Total power consumption of the system for: （8）。 5. The OFDM-based wireless communication method according to claim 3, characterized in that, Total information transmission rate in a communication system for: （7）。 6. The OFDM-based wireless communication method according to claim 5, characterized in that, Information reception rate of relay nodes Represented as: （1）。 7. The OFDM-based wireless communication method according to claim 5, characterized in that, Information reception rate at the receiver end for: （4）。 8. A wireless communication system based on OFDM, characterized in that, include The module is used to construct a system energy efficiency optimization problem with the goal of minimizing system energy efficiency, while ensuring system information rate and communication quality. The solution module is used to solve the system energy efficiency optimization problem and obtain the first-stage optimal power allocation strategy. and the optimal power allocation strategy in the second stage ; The communication module is used to implement the first-stage power optimal allocation strategy. and the optimal power allocation strategy in the second stage Wireless communication is achieved using wireless power-carrying communication technology.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the OFDM-based wireless communication method as described in any one of claims 1-7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the OFDM-based wireless communication method as described in any one of claims 1-7.

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