A Cooperative Resource Allocation Method and Device Based on Hybrid Multiple Access Technology in an Internet of Things System

Abstract

The present invention discloses a cooperative resource allocation method and device based on hybrid multiple access technology in an Internet of Things system. The system includes a base station, M hybrid relays, and M groups of Internet of Things terminals (each hybrid relay serves one group of terminals). The communication between the terminals and the base station is completed in three stages. First, the hybrid relays wirelessly broadcast energy to the terminals. Second, the terminals use the NOMA protocol to send data to the hybrid relays. Finally, the relays send data to the base station through the TDMA protocol. A cooperative resource allocation method based on hybrid multiple access technology of the present invention optimizes the transmission time and power allocation, improves the overall communication efficiency of the system, and optimizes the total transmission data volume of the system.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communication, and relates to a cooperative resource allocation method based on hybrid multiple access technology in an Internet of Things (IoT) system. Background Art

[0002] With the popularization of wireless communication services and the expansion of service types, the number of users and the amount of transmitted data in a communication system have increased significantly. A single multiple access method will not be able to adapt to such a large amount of data, and large-scale data transmission will inevitably lead to greater energy consumption. Hybrid multiple access technology is a technology in which orthogonal multiple access technology (OMA) and non-orthogonal multiple access technology (NOMA) coexist in the same device, and the access method is adaptively selected according to needs. It has been verified that the number of accesses of the hybrid multiple access mechanism is higher than that of a single multiple access mechanism, meeting the demand for an increasing number of users. Wireless energy transfer technology can increase the coverage area of existing IoT systems and enable IoT terminals to have a longer battery life, improving the energy efficiency of existing IoT systems.

[0003] Combining hybrid multiple access technology with relay technology can effectively increase the amount and efficiency of data transmission in an IoT system; while wireless energy transfer technology can make up for the energy consumption caused by the system's data processing volume. However, in the prior art, there is a lack of a method for allocating resources in an IoT system, resulting in energy waste and consumption and reducing the information transmission efficiency. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a cooperative resource allocation method and device based on hybrid multiple access technology in an IoT system. The wireless energy transfer technology can be used to reduce the energy burden of users for data transmission, and through the hybrid multiple access technology, an efficient transmission method in which multiple IoT terminals simultaneously transmit data to a hybrid relay and multiple hybrid relays simultaneously transmit data to a base station is realized, effectively improving the transmission efficiency of the system.

[0005] To achieve the above object, the present invention is implemented by the following technical solutions:

[0006] In a first aspect, the present invention provides a cooperative resource allocation method based on hybrid multiple access technology in an IoT system. Based on the IoT system, the IoT system includes multiple IoT terminals, multiple hybrid relays, and a base station; multiple hybrid relays are all connected to the base station, and one hybrid relay provides services for a group of terminals;

[0007] The process of data transmission from a terminal to the base station includes: downlink energy transfer of the hybrid relay, uplink information transfer from the terminal to the hybrid relay, and uplink information transfer from the relay to the base station;

[0008] In the downlink energy transmission phase of the hybrid relay, the hybrid relay simultaneously transmits wireless energy to all the terminal devices it serves; in the uplink information transmission phase from the terminal to the hybrid relay, the terminal uses the NOMA method to transmit data to the hybrid relay; in the uplink information transmission phase from the relay to the base station, the hybrid relay uses the TDMA method to transmit data to the base station.

[0009] The said cooperative resource allocation method includes the following steps:

[0010] Step 1: Establish an optimization problem model solved by the cooperative resource allocation method based on the hybrid multiple access technology in the Internet of Things system;

[0011] Step 2: Transform the said optimization problem model, and optimize and calculate the transmission time and power allocation for all combinations of hybrid relays and channels;

[0012] Step 3: Calculate the power for the hybrid relay to send data to the base station and the transmission power for the Internet of Things terminal to send data to the hybrid relay.

[0013] Furthermore, establishing an optimization problem model solved by the cooperative resource allocation method based on the hybrid multiple access technology in the Internet of Things system includes:

[0014] Establish an optimization problem model P1 solved by the cooperative resource allocation method based on the hybrid multiple access technology in the Internet of Things system:

[0015] P1:

[0016] Constraint C1:

[0017] Constraint C2: τ1 + ∑ m∈M (τ 2，m + τ 3，m ) ≤ 1

[0018] Constraint C3:

[0019] Constraint C4:

[0020] Constraint C5:

[0021] The objective of P1 is to maximize the total amount of data transmitted from all the Internet of Things terminal devices served by the hybrid relay to the base station. Among them, the amount of transmission data from the Internet of Things terminal to the relay and the amount of data transmitted from the relay to the base station are respectively and Since the Internet of Things terminal transmits data to the base station in the above two phases, the total data volume of the system is determined by the smaller data volume in the two-phase transmission.

[0022] The set of all hybrid relays in the system is M, and the set of IoT terminals responsible for the m-th hybrid relay is K m , and the set of all channels is N; τ1, τ 2，m and τ 3，m are respectively the time for all hybrid relays to transmit wireless energy to the IoT terminals they are responsible for, the time for the IoT terminals to send information to their affiliated hybrid relay m, and the time for the hybrid relay m to send data to the base station. p m，n , q m，n and b m，n，k respectively represent the power for the hybrid relay m to transmit energy to the terminal on channel n, the transmit power for the hybrid relay m to send the data collected from the terminal to the base station on channel n, and the transmit power for the k-th terminal responsible for the m-th hybrid relay on channel n; g m，n，k , h m，n，k and γ m，n respectively represent the channel gain on channel n between the m-th hybrid relay and the k-th terminal it is responsible for, the channel gain on channel n between the k-th terminal and its affiliated hybrid relay m, and the channel gain on channel n between the m-th hybrid relay and the base station; P m and E m respectively represent the peak transmit power limit and the total energy consumption limit of the hybrid relay m on each channel;

[0023] Constraint C1 means that the energy consumed by the k-th terminal device responsible for the m-th hybrid relay in the second transmission time slot is not greater than the energy it collects in the first time slot; Constraint C2 means that the sum of the three transmission time slots of each hybrid relay is not greater than the normalized 1; Constraint C3 means that each transmission time slot is a positive number; Constraint C4 means the total energy consumption constraint of each hybrid relay; Constraint C5 means that the transmit power of the hybrid relay is constrained and the transmit power of the IoT terminal device is a positive number.

[0024] Furthermore, transform the optimization problem model. For all combinations of hybrid relays and channels, optimize and calculate the transmission time and power allocation, including:

[0025] Step 2-1: Let the transmit power of all hybrid relays when transmitting energy to the terminal on all channels be its maximum value, that is

[0026] Step 2-2: Introduce an auxiliary variable e m，n，k =τ 2，m b m，n，k , and rewrite problem P1 as P2:

[0027] P2:

[0028] Constraint C6:

[0029] Constraint C7:

[0030] Constraint C8:

[0031] Constraint C2 and Constraint C3 remain unchanged.

[0032] Among them,

[0033] Step 2 - 3: Solve problem P2 using the Lagrange multiplier method, that is, introduce an auxiliary variable λ and search for its value using the bisection method. Specifically, let the initial value range of λ be [λ min , λ max , and repeat steps 2 - 4 to 2 - 10 until λ converges.

[0034] Step 2 - 4: Let

[0035] Step 2 - 5: For all hybrid relays m, solve the following problem to obtain the part of the Lagrangian dual function related to each relay:

[0036] P3:

[0037] Constraint C9:

[0038] Constraint C10: τ 1，m MP m +∑ n∈N u m，n ≤E m

[0039] Constraint C11:

[0040] Constraint C12: τ l，m ≥0, τ 2，m ≥0, τ 3，m ≥0

[0041] Among them, τ 1，m is the value of τ1 in the case of maximizing the part of the Lagrangian dual function related to hybrid relay m.

[0042] Step 2 - 6: To solve problem P3, introduce an auxiliary variable η to reconstruct problem P3 as follows:

[0043] P4:

[0044] Constraint C13:

[0045] Constraint C14:

[0046] Constraints C9 - C12 remain unchanged

[0047] Among them, Constraints C13 and C14 require that the value of the Lagrangian dual function related to each hybrid relay m is greater than the auxiliary variable η. Given the initial search interval [η min , η max , the bisection method is used to search for the value of η until it converges.

[0048] Step 2 - 7: The energy transfer time slot length τ1 is determined by the hybrid relay with the longest required time:

[0049] Step 2 - 8: Set the wireless energy transmission power of the m - th hybrid relay on the n - th channel to the maximum value of That is:

[0050] Step 2 - 9: If ∑ m∈M (τ 1，m + τ 2，m + τ 3，m ) > 1, then let λ min = λ, otherwise, let λ max = λ.

[0051] Step 2 - 10: If λ does not converge, return to execute Step 2 - 4; if it converges, end.

[0052] Furthermore, given the initial search interval [η min , η max , the steps of using the bisection method to search for the value of η until it converges include:

[0053] Step 2 - 6 - 1: Let

[0054] Step 2 - 6 - 2: Model Problem P5 to perform a feasibility test on Problem P4 for the given η:

[0055] P5:

[0056] Constraints C9, Constraints C11 - C14

[0057] Step 2 - 6 - 3: Let Constraint C9 hold with equality, that is Get the expression of τ 1，m of

[0058] Step 2-6-4: Substitute τ 1，m into problem P5 to obtain problem P6:

[0059] P6:

[0060] Constraint C15:

[0061] Constraint C16:

[0062] Constraint C17:

[0063] Constraint C18:

[0064] Constraint C19:

[0065] Constraint C20: τ 2，m ≥0, τ 3，m ≥0

[0066] Step 2-6-5: Solve problem P6 using the Lagrange multiplier method.

[0067] Step 2-6-6: Obtain the value of τ according to 1，m .

[0068] Step 2-6-7: When τ 1，m MP m + ∑ n∈N u m，n ≤ E m , let η min = η; otherwise, let η max = η.

[0069] Step 2-6-8: If η does not converge, return to execute Step 2-6-1; if it converges, continue to execute the next step.

[0070] Furthermore, in Step 2-6-5, solving problem P6 using the Lagrange multiplier method includes:

[0071] Step 2-6-5-1: Introduce Lagrange multipliers μ, v, {π k} and {ω k}, and initialize μ, v, {π k} and {ω k}.

[0072] Step 2-6-5-2: Rewrite problem P6 as problem P7 using the Lagrange multiplier method:

[0073] P7:

[0074] Constraints C19, Constraint C20

[0075] where, is the Lagrange dual function with respect to τ 2，m , τ 3，m , e m and u m .

[0076] Step 2-6-5-3: For each channel n of the hybrid relay m, given τ 2，m and τ 3，m , solve for the values of e m and u m according to the KKT conditions:

[0077]

[0078]

[0079]

[0080] Step 2-6-5-4: Given the values of e m and u m , obtain the expressions for τ 2，m , τ 3，m by taking the partial derivatives of the part of the Lagrange dual function related to τ 2，m , τ 3，m and setting the partial derivatives to zero:

[0081] The value of τ 2，m is obtained by binary search on the following equation:

[0082] The value of τ 3，m is obtained by binary search on the following equation:

[0083] Step 2-6-5-5: If the objective function of problem P7 does not converge, go back to Step 2-6-5-3.

[0084] Step 2-6-5-6: Update μ, v, {π k}, and {ω k}.

[0085] Step 2-6-5-7: If μ, v, {π k}, and {ω k} do not converge, then return to Step 2-6-5-3 until convergence.

[0086] Furthermore, calculate the power for the hybrid relay to send data to the base station and the transmission power for the IoT terminal to send data to the hybrid relay, including:

[0087] Set the transmission power for the hybrid relay to send the data collected from the terminals to the base station as: and the transmission power of the kth terminal responsible for the mth hybrid relay on channel n as:

[0088] In a second aspect, the present invention provides a cooperative resource allocation device based on hybrid multiple access technology in an IoT system. Based on the IoT system, the IoT system includes multiple IoT terminals, multiple hybrid relays, and a base station; multiple hybrid relays are all connected to the base station, and one hybrid relay provides services for a group of terminals;

[0089] The process of the terminal transmitting data to the base station includes: hybrid relay downlink energy transmission, terminal uplink information transmission to the hybrid relay, and relay uplink information transmission to the base station;

[0090] In the hybrid relay downlink energy transmission stage, the hybrid relay simultaneously transmits wireless energy to all terminal devices it serves; in the terminal uplink information transmission stage to the hybrid relay, the terminal uses the NOMA method to transmit data to the hybrid relay; in the relay uplink information transmission stage to the base station, the hybrid relay uses the TDMA method to transmit data to the base station.

[0091] The cooperative resource allocation device includes:

[0092] Modeling module: used to establish an optimization problem model solved by the cooperative resource allocation method based on hybrid multiple access technology in the IoT system;

[0093] Optimization module: used to transform the optimization problem model, and optimize and calculate the transmission time and power allocation for all combinations of hybrid relays and channels;

[0094] Output module: used to calculate the power for the hybrid relay to send data to the base station and the transmission power for the IoT terminal to send data to the hybrid relay.

[0095] Compared with the prior art, the beneficial effects achieved by the present invention:

[0096] 1. The present invention proposes a cooperative resource allocation method based on hybrid multiple access technology. IoT terminals communicate with the base station through relays. The uplink transmission process requires a total of three time slots. First, the hybrid relay broadcasts radio signals to the IoT terminals it is responsible for in a broadcast manner. The terminals extract energy from this signal and use it for signal transmission in the second time slot. TDMA is used among multiple terminals to transmit signals to the hybrid relay. NOMA is used among multiple hybrid relays to transmit superimposed signals to the base station in the third time slot.

[0097] 2. The cooperative resource allocation method based on hybrid multiple access technology proposed by the present invention proposes a new multi-terminal data transmission method, realizing the communication between a large number of IoT terminals and the base station with the help of relays in hybrid multiple access technology, and improving the communication efficiency of the system.

[0098] 3. The method for providing energy for terminals using wireless transmission proposed by the present invention can effectively reduce the energy consumption of terminals, and can effectively balance the information transmission in the uplink and the energy harvesting in the downlink, and maximize the corresponding information transmission rate according to the amount of harvested energy. Description of the Drawings

[0099] Figure 1 Cooperative resource allocation system model diagram based on hybrid multiple access technology;

[0100] Figure 2 Flowchart of the cooperative resource allocation algorithm based on hybrid multiple access technology;

[0101] Figure 3 Frame structure diagram of the cooperative resource allocation algorithm based on hybrid multiple access technology. Detailed Implementation Manner

[0102] The present invention will be further described below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and should not be used to limit the protection scope of the present invention.

[0103] Embodiment 1:

[0104] This embodiment provides a cooperative resource allocation method based on hybrid multiple access technology in an Internet of Things (IoT) system, which can be applied to a system consisting of one base station, M hybrid relays, and M groups of IoT terminals. A hybrid relay serves a group of terminals. Here, the hybrid relay is a repeater capable of providing hybrid multiple access technology, and the hybrid multiple access in the present invention is a combination of NOMA and TDMA technologies. The process of the terminals transmitting data to the base station is divided into three stages, namely, the hybrid relay transmitting downlink energy to the terminals, the terminals transmitting uplink information to the hybrid relay, and the relay transmitting uplink information to the base station. In the stage of the hybrid relay transmitting downlink energy to the terminals, the hybrid relay simultaneously transmits wireless energy to all the terminal devices it serves; in the stage of the terminals transmitting uplink information to the hybrid relay, the terminals use the NOMA method to transmit data to the hybrid relay; in the stage of the relay transmitting uplink information to the base station, the hybrid relay uses the TDMA method to transmit data to the base station. This method maximizes the total transmission data volume of the system by optimizing the transmission time and power allocation. The steps of the cooperative resource allocation method are as follows:

[0105] Step 1: Establish an optimization problem model solved by the cooperative resource allocation method based on hybrid multiple access technology in the IoT system;

[0106] Establish the optimization problem model P1 solved by the cooperative resource allocation method based on hybrid multiple access technology in the IoT system:

[0107] P1:

[0108] Constraint C1:

[0109] Constraint C2: τ1 + ∑ m∈M (τ 2，m +τ 3，m ) ≤ 1

[0110] Constraint C3:

[0111] Constraint C4:

[0112] Constraint C5:

[0113] The objective of P1 is to maximize the total amount of data transmitted from all the IoT terminal devices served by the hybrid relay to the base station. Among them, the amount of transmission data from the IoT terminal to the relay and the amount of data transmitted from the relay to the base station are respectively and Since the data transmission from the IoT terminal to the base station is divided into the above two stages, the total data volume of the system is determined by the smaller data volume in the two-stage transmission. The set of all hybrid relays in this system is M, and the set of IoT terminals responsible for the m-th hybrid relay is Km , the set of all channels is N; τ1, τ 2，m and τ 3，m are respectively the time for all hybrid relays to transmit wireless energy to the IoT terminals under their responsibility, the time for the IoT terminals to send information to their affiliated hybrid relay m, and the time for the hybrid relay m to send data to the base station. p m，n , q m，n and b m，n，k respectively represent the power for the hybrid relay m to transmit energy to the terminal on channel n, the transmit power for the hybrid relay m to send the data collected from the terminal to the base station on channel n, and the transmit power for the k-th terminal under the responsibility of the m-th hybrid relay on channel n; g m，n， k, h m，n，k and γ m，n respectively represent the channel gain on channel n between the m-th hybrid relay and the k-th terminal under its responsibility, the channel gain on channel n between the k-th terminal and its affiliated hybrid relay m, and the channel gain on channel n between the m-th hybrid relay and the base station; P m and E m respectively represent the peak transmit power limit and the total energy consumption limit of the hybrid relay m on each channel;

[0114] Constraint C1 means that the energy consumed by the k-th terminal device under the responsibility of the m-th hybrid relay in the second transmission time slot is not greater than the energy it collects in the first time slot; Constraint C2 means that the sum of the three transmission time slots of each hybrid relay is not greater than the normalization 1; Constraint C3 means that each transmission time slot is a positive number; Constraint C4 means the total energy consumption constraint of each hybrid relay; Constraint C5 means that the transmit power of the hybrid relay is constrained and the transmit power of the IoT terminal device is a positive number.

[0115] Step 2: Transform the optimization problem model described in Step 1. For all combinations of hybrid relays and channels, optimize and calculate the transmission time and power allocation;

[0116] Step 2-1: Let the transmit power of all hybrid relays when transmitting energy to the terminals on all channels be its maximum value, that is

[0117] Step 2-2: Introduce the auxiliary variable and rewrite problem P1 as P2:

[0118] P2:

[0119] Constraint C6:

[0120] Constraint C7:

[0121] Constraint C8:

[0122] Constraints C2 and C3 remain unchanged.

[0123] Among them,

[0124] Step 2-3: Solve problem P2 using the Lagrange multiplier method, that is, introduce an auxiliary variable λ and search for its value using the bisection method. Specifically, let the initial value range of λ be [λ min , λ max , and repeat steps 2-4 to 2-10 until λ converges.

[0125] Step 2-4: Let

[0126] Step 2-5: For all hybrid relays m, solve the following problem to obtain the part of the Lagrangian dual function related to each relay:

[0127] P3:

[0128] Constraint C9:

[0129] Constraint C10: τ 1，m MP m +∑ n∈N u m，n ≤ E m

[0130] Constraint C11:

[0131] Constraint C12: τ 1，m ≥ 0, τ 2，m ≥ 0, τ 3，m ≥ 0

[0132] Among them, τ 1，m is the value of τ1 when maximizing the part of the Lagrangian dual function related to hybrid relay m.

[0133] Step 2-6: To solve problem P3, introduce an auxiliary variable η to reconstruct problem P3 as follows:

[0134] P4:

[0135] Constraint C13:

[0136] Constraint C14:

[0137] Constraints C9 - C12 remain unchanged

[0138] Among them, constraints C13 and C14 require that the value of the Lagrangian dual function related to each hybrid relay m is greater than the auxiliary variable η. Given the initial search interval [η min , η max , the bisection method is used to search for the value of η until it converges. The specific steps are as follows:

[0139] Step 2 - 6 - 1: Let

[0140] Step 2 - 6 - 2: Model problem P5 to perform a feasibility test on problem P4 for the given η:

[0141] P5:

[0142] Constraints C9, C11 - C14

[0143] Step 2 - 6 - 3: Let the equality of constraint C9 hold, that is Obtain the expression of τ 1，m

[0144] Step 2 - 6 - 4: Substitute τ 1，m into problem P5 to obtain problem P6:

[0145] P6:

[0146] Constraint C15:

[0147] Constraint C16:

[0148] Constraint C17:

[0149] Constraint C18:

[0150] Constraint C19:

[0151] Constraint C20: τ 2，m ≥0, τ 3，m ≥0

[0152] Step 2 - 6 - 5: Use the Lagrange multiplier method to solve problem P6.

[0153] Step 2 - 6 - 6: According to Obtain the value of τ 1，m .

[0154] ​Step 2-6-7: When τ 1，m MP m +∑ n∈N u m，n ≤E m , let η min = η; otherwise, let η max = η.

[0155] Step 2-6-8: If η does not converge, return to execute Step 2-6-1; if it converges, continue to execute the next step.

[0156] Step 2-7: The energy transfer time slot length τ1 is determined by the hybrid relay with the longest required time:

[0157] Step 2-8: Set the wireless energy transmission power of the m-th hybrid relay on the n-th channel to be the maximum value of That is:

[0158] Step 2-9: If ∑ m∈M (τ 1，m +τ 2，m +τ 3，m ) > 1, let λ min = λ, otherwise, let λ max = λ.

[0159] Step 2-10: If λ does not converge, return to execute Step 2-4; if it converges, end.

[0160] Among them, the specific content of Step 2-6-5 is:

[0161] Step 2-6-5-1: Introduce Lagrange multipliers μ, v, {π k} and {ω k}, and initialize μ, v, {π k} and {ω k}.

[0162] Step 2-6-5-2: Use the Lagrange multiplier method to rewrite problem P6 as problem P7:

[0163] P7:

[0164] Constraint C19, Constraint C20

[0165] Among them, is about τ 2，m 、τ 3，m 、e mand u m The Lagrangian dual function of

[0166] Step 2-6-5-3: For each channel n of the hybrid relay m, given τ 2，m and τ 3，m , solve for e m and u m values according to the KKT conditions:

[0167]

[0168]

[0169]

[0170] Step 2-6-5-4: Given the values of e m and u m , by taking the partial derivatives of the part of the Lagrangian dual function related to τ 2，m and τ 3，m and setting the partial derivatives to zero, obtain the expressions for τ 2，m and τ 3，m :

[0171] The value of τ 2，m is obtained by binary search on the following formula:

[0172] The value of τ 3，m is obtained by binary search on the following formula:

[0173] Step 2-6-5-5: If the objective function of problem P7 does not converge, go back to step 2-6-5-3.

[0174] Step 2-6-5-6: Update μ, v, {π k} and {ω k} using the ellipsoid method.

[0175] Step 2-6-5-7: If μ, v, {π k} and {ω k} do not converge, then return to step 2-6-5-3.

[0176] Step 3: Calculate the power for the hybrid relay to send data to the base station and the transmission power for the IoT terminal to send data to the hybrid relay.

[0177] Set the transmit power for the hybrid relay to send the data collected from the terminal to the base station as: and the transmit power for the k-th terminal responsible for the m-th hybrid relay on channel n as:

[0178] Embodiment 2:

[0179] This embodiment provides a cooperative resource allocation device based on hybrid multiple access technology in an Internet of Things system. Based on the Internet of Things system, the Internet of Things system includes multiple Internet of Things terminals, multiple hybrid relays, and a base station; multiple hybrid relays are all connected to the base station, and one hybrid relay provides services for a group of terminals;

[0180] The process of data transmission from the terminal to the base station includes: downlink energy transmission by the hybrid relay, uplink information transmission from the terminal to the hybrid relay, and uplink information transmission from the relay to the base station;

[0181] In the downlink energy transmission stage of the hybrid relay, the hybrid relay simultaneously transmits wireless energy to all terminal devices it serves; in the uplink information transmission stage from the terminal to the hybrid relay, the terminal uses the NOMA method to transmit data to the hybrid relay; in the uplink information transmission stage from the relay to the base station, the hybrid relay uses the TDMA method to transmit data to the base station.

[0182] The cooperative resource allocation device includes:

[0183] Modeling module: used to establish an optimization problem model solved by the cooperative resource allocation method based on hybrid multiple access technology in the Internet of Things system;

[0184] Optimization module: used to transform the optimization problem model, and optimize and calculate the transmission time and power allocation for all combinations of hybrid relays and channels;

[0185] Output module: used to calculate the power for the hybrid relay to send data to the base station and the transmission power for the Internet of Things terminal to send data to the hybrid relay.

[0186] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented 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.

[0187] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a means for implementing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or a means for implementing the functions specified in one or more of the blocks.

[0188] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to operate in a specific manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction means that implements the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or a means for implementing the functions specified in one or more of the blocks.

[0189] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operational steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or a means for implementing the functions specified in one or more of the blocks.

[0190] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principles of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A cooperative resource allocation method based on hybrid multiple access technology in an Internet of Things system, characterized in that Based on the Internet of Things (IoT) system, the IoT system includes multiple IoT terminals, multiple hybrid relays, and a base station; multiple hybrid relays are all connected to the base station, and one hybrid relay provides services for a group of terminals; The process of data transmission from the terminal to the base station includes: downlink energy transmission by the hybrid relay, uplink information transmission from the terminal to the hybrid relay, and uplink information transmission from the relay to the base station; In the downlink energy transmission stage of the hybrid relay, the hybrid relay simultaneously transmits wireless energy to all terminal devices it serves; in the uplink information transmission stage from the terminal to the hybrid relay, the terminal uses the NOMA method to transmit data to the hybrid relay; in the uplink information transmission stage from the relay to the base station, the hybrid relay uses the TDMA method to transmit data to the base station; The cooperative resource allocation method includes the following steps: Step 1: Establish an optimization problem model solved by the cooperative resource allocation method based on the hybrid multiple access technology in the IoT system; Step 2: Transform the optimization problem model, and for all combinations of hybrid relays and channels, optimize and calculate the transmission time and power allocation; Step 3: Calculate the power for the hybrid relay to send data to the base station and the transmission power for the IoT terminal to send data to the hybrid relay; Establishing an optimization problem model solved by the cooperative resource allocation method based on the hybrid multiple access technology in the IoT system includes: Establish the optimization problem model P1 of the cooperative resource allocation method based on the hybrid multiple access technology in the IoT system: P1: Constraint C1: Constraint C2: Constraint C3: Constraint C4: Constraint C5: The objective of P1 is to maximize the total amount of data transmitted from all IoT terminal devices served by the hybrid relay to the base station, where the amount of transmission data from the IoT terminal to the relay and the amount of data transmitted from the relay to the base station are respectively and The set of all hybrid relays in the system is The set of IoT terminals responsible for the m-th hybrid relay is The set of all channels is τ1, τ 2,m and τ 3,m are respectively the time for all hybrid relays to transmit wireless energy to the IoT terminals they are responsible for, the time for the IoT terminals to send information to the m-th hybrid relay they belong to, and the time for the m-th hybrid relay to send data to the base station. p m,n 、q m,n and b m,n,k respectively represent the power of the m-th hybrid relay to transmit energy to the terminal on channel n, the transmit power of the m-th hybrid relay to send the data collected from the terminal to the base station on channel n, and the transmit power of the k-th terminal responsible for the m-th hybrid relay on channel n; g m,n,k 、h m,n,k and γ m,n respectively represent the channel gain on channel n between the m-th hybrid relay and the k-th terminal it is responsible for, the channel gain on channel n between the k-th terminal and the m-th hybrid relay it belongs to, and the channel gain on channel n between the m-th hybrid relay and the base station; P m and E m respectively represent the peak transmit power limit and the total energy consumption limit of the m-th hybrid relay on each channel; Constraint C1 means that the energy consumed by the k-th terminal device responsible for by the m-th hybrid relay in the second transmission time slot is not greater than the energy it collects in the first time slot; Constraint C2 means that the sum of the three transmission time slots of each hybrid relay is not greater than 1 after normalization; Constraint C3 means that each transmission time slot is a positive number; Constraint C4 means the total energy consumption constraint of each hybrid relay; Constraint C5 means that the transmission power of the hybrid relay is constrained and the transmission power of the IoT terminal device is a positive number; Transform the optimization problem model, and for all combinations of hybrid relays and channels, optimize and calculate the transmission time and power allocation, including: Step 2-1: Let the transmit power of all hybrid relays when transmitting energy to the terminal on all channels be its maximum value, i.e., Step 2-2: Introduce an auxiliary variable e m,n,k = τ 2,m b m,n,k , and rewrite problem P1 as P2: P2： Constraint C6: Constraint C7: Constraint C8: Constraints C2 and C3 remain unchanged; Among them, Step 2-3: Solve problem P2 using the Lagrange multiplier method, that is, introduce an auxiliary variable λ and search for its value using the bisection method; specifically, let the initial value range of λ be [λ min , λ max , repeat steps 2-4 to 2-10 until λ converges; Step 2-4: Let Step 2-5: For all hybrid relays m, solve the following problem to obtain the partial Lagrangian dual function related to each relay: P3： Constraint C9: Constraint C10: Constraint C11: Constraint C12: τ 1,m ≥0, τ 2,m ≥0, τ 3,m ≥0 where τ 1,m is the value of τ1 in the case of maximizing the part of the Lagrangian dual function related to the hybrid relay m; Step 2-6: To solve problem P3, introduce an auxiliary variable η to reconstruct problem P3 as follows: P4： Constraint C13: Constraint C14: Constraints C9 - C12 remain unchanged Among them, the constraints C13 and C14 require that the Lagrangian dual function value related to each hybrid relay m is greater than the auxiliary variable η; given the initial search interval [η min , η max of η, the bisection method is used to search for the value of η until it converges; Step 2-7: The energy transfer time slot length τ1 is determined by the hybrid relay with the longest required time: Step 2-8: Set the wireless energy transmission power of the m-th hybrid relay on the n-th channel to the maximum value of That is: Step 2-9: If then let λ min = λ, otherwise, let λ max = λ; Step 2-10: If λ does not converge, return to execute Step 2-4; if it converges, end.

2. The cooperative resource allocation method according to claim 1, wherein Given the initial search interval of η [η min , η max , the steps of using the bisection method to search for the value of η until it converges include: Step 2-6-1: Let Step 2-6-2: Model problem P5 to conduct a feasibility test on problem P4 for the given η: P5： Constraints C9, C11 - C14 Step 2-6-3: Make the equality of constraint C9 hold, that is Obtain the expression of τ 1,m ​ Step 2-6-4: Substitute τ 1,m into problem P5 to obtain problem P6: P6： Constraint C15: Constraint C16: Constraint C17: Constraint C18: Constraint C19: Constraint C20: τ 2,m ≥0, τ 3,m ≥0 Step 2-6-5: Use the Lagrange multiplier method to solve problem P6; Step 2-6-6: According to obtain the value of τ 1,m ; Step 2-6-7: When occurs, let η min = η; otherwise, let η max = η; Step 2-6-8: If η does not converge, return to execute Step 2-6-1.

3. The cooperative resource allocation method according to claim 2, wherein In Step 2-6-5, using the Lagrange multiplier method to solve problem P6 includes: Step 2-6-5-1: Introduce Lagrange multipliers μ, v, {π k}, and {ω k}, and initialize μ, v, {π k}, and {ω k}; Step 2-6-5-2: Use the Lagrange multiplier method to rewrite problem P6 as problem P7: P7： Constraints C19, C20 Among them, Regarding τ 2,m τ 3,m e m and u m is the Lagrangian dual function; Step 2-6-5-3: For each channel n of the hybrid relay m, given τ 2,m and τ 3,m , solve for the values of e m and u m according to the KTT condition: Step 2-6-5-4: Given e m and u m values, by taking the partial derivatives of the Lagrangian dual function with respect to the parts related to τ 2,m and τ 3,m and setting the partial derivatives to zero, the expressions for τ 2,m and τ 3,m are obtained: τ 2,m The value of is obtained by performing a binary search on the following formula: τ 3,m The value of is obtained by binary search for the following formula: Step 2-6-5-5: If the objective function of problem P7 does not converge, go back to Step 2-6-5-3; Step 2-6-5-6: Update μ, v, {π k}, and {ω k}; Step 2-6-5-7: If μ, v, {π k}, and {ω k} do not converge, then return to Step 2-6-5-3 until convergence is achieved.

4. The cooperative resource allocation method according to claim 1, wherein Calculate the power for the hybrid relay to send data to the base station and the transmission power for the IoT terminal to send data to the hybrid relay, including: Set the transmission power of the hybrid relay to send the data collected from the terminal to the base station as: And the transmission power of the k-th terminal responsible for the m-th hybrid relay on channel n is:

5. A cooperative resource allocation device based on hybrid multiple access technology in an Internet of Things system for performing the method according to claim 1, characterized in that, Based on the IoT system, the IoT system includes multiple IoT terminals, multiple hybrid relays, and a base station; multiple hybrid relays are all connected to the base station, and one hybrid relay provides services for a group of terminals; The process of data transmission from the terminal to the base station includes: downlink energy transmission of the hybrid relay, uplink information transmission from the terminal to the hybrid relay, and uplink information transmission from the relay to the base station; In the downlink energy transmission stage of the hybrid relay, the hybrid relay simultaneously transmits wireless energy to all terminal devices it serves; in the uplink information transmission stage from the terminal to the hybrid relay, the terminal uses the NOMA method to transmit data to the hybrid relay; in the uplink information transmission stage from the relay to the base station, the hybrid relay uses the TDMA method to transmit data to the base station; The cooperative resource allocation device includes: Modeling module: used to establish an optimization problem model solved by the cooperative resource allocation method based on the hybrid multiple access technology in the IoT system; Optimization module: used to transform the optimization problem model, and optimize and calculate the transmission time and power allocation for all combinations of hybrid relays and channels; Output module: used to calculate the power for the hybrid relay to send data to the base station and the transmission power for the IoT terminal to send data to the hybrid relay.

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