A method for allocating communication resources for spectrum sharing of NOMA for smart grid

Abstract

The application relates to a NOMA spectrum sharing communication resource allocation method for a smart grid, and belongs to the technical field of smart grid demand side communication network optimization, which comprises the following steps: constructing a power company cost and communication rate relationship function; quantifying the communication reliability requirements of a licensed network and a power communication network; performing power allocation of a relay node; and performing power proportion allocation of downlink NOMA. Under the premise of meeting the service quality of the licensed network, the non-cooperative relay cognitive NOMA technology is adopted, the transmission rate of the power communication network is improved, and the cost of the power company is reduced; under the constraint of meeting the service quality of the licensed network, the achievable rate of the power communication network is maximized, interference management and power allocation are performed by considering the same layer interference and NOMA self-interference, so that normal licensed network communication services are ensured and the cost of each power company is reduced.

Description

Technical Field

[0001] This invention relates to a NOMA spectrum sharing communication resource allocation method for smart grids, belonging to the field of smart grid demand-side communication network optimization technology. Background Technology

[0002] In recent years, the Internet of Things (IoT) has attracted widespread attention. Viewed as part of the future internet, the IoT will connect billions of smart communication devices. The future of the internet will consist of interconnected IoT devices, which will further expand the boundaries of the internet world by connecting physical entities and virtual components. Smart grids, as a cyber-physical system, integrate automated control and advanced communication technologies into the power grid infrastructure for energy management and demand response. The widely commercialized 5G networks and 5G-based IoT can undoubtedly provide a better infrastructure for demand response.

[0003] Demand Response Management (DRM) can narrow the gap between electricity supply and demand by dynamically influencing consumer demand. However, when large amounts of data are transmitted simultaneously through Data Aggregation Units (DAUs), packet loss can occur in densely populated data aggregation units due to spectrum and transmission rate limitations. Packet loss increases the volatility of predicted demand. Therefore, reducing packet loss can mitigate demand volatility and costs for power companies. Advanced communication technologies such as cooperative relay, cognitive radio, and non-orthogonal multiple access (NOMA) can be employed in communication networks to improve information transmission rates and expand spectrum resources, thereby reducing packet loss.

[0004] However, the individual application of these communication technologies cannot simultaneously and effectively improve both information transmission rate and spectral efficiency. Therefore, a communication resource allocation method that simultaneously considers information transmission rate and spectral efficiency is of paramount importance. Summary of the Invention

[0005] The purpose of this invention is to provide a NOMA spectrum sharing communication resource allocation method for smart grids, which quantifies the reliability requirements of licensed network communication under tolerable economic losses and communication interference. It allocates radio resources based on relay power and relay power allocation ratio, and maximizes the total rate of power communication network without affecting the reliability requirements of licensed network, thereby ensuring normal licensed network communication services and reducing costs for various power companies.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for allocating NOMA spectrum sharing communication resources for smart grids includes the following steps:

[0008] Step 1: Constructing the function relating power company costs to communication rates;

[0009] Step 2: Quantify the communication reliability requirements of the authorized network and the power communication network;

[0010] Step 3: Perform power allocation for relay nodes;

[0011] Step 4: Perform power ratio allocation for downlink NOMA.

[0012] A further improvement to the technical solution of this invention lies in the following: Step 1 includes the construction of the power company's cost function and the transmission rate function of the receiving end during data transmission, specifically:

[0013] The licensed network provides spectrum to the EPC network, and the relays in the EPC network transmit information for the licensed network, thus sharing spectrum resources. The base station sends information to licensed users through downlink transmission in the licensed network, and the control center periodically issues control commands to the gateway through the DAU in the downlink transmission. Assume that there is severe shadow interference, there is no direct connection between the DAU and the gateway, and there is also no direct connection between the base station and the licensed users. When the relay receives information, it constitutes an uplink NOMA system, and when the relay sends information, it constitutes a downlink NOMA system.

[0014] The principle of power allocation based on channel conditions is adopted, that is, high power is allocated to receivers with poor channel conditions and low power is allocated to receivers with good channel conditions. Therefore, two schemes are generated: SIC is implemented at the gateway and is called D-SIC scheme, and SIC is implemented at authorized users and is called B-SIC scheme.

[0015] The Taguchi loss function is introduced to describe the cost characteristics of utility companies. The cost of each utility company can be expressed as:

[0016]

[0017] In the formula, ξ represents the increase in variance due to the loss of a single data packet. χ represents the variance without packet loss, where χ is a constant. s Indicates a sampling period. This is the retention cost for power company i, R i This is the actual transmission rate of DAU i. It is the target transmission rate;

[0018] To improve spectrum utilization, NOMA technology is used to provide services to both the EPC network and the licensed network simultaneously. Assuming that each node has perfect channel state information, a decode-forward relay strategy consisting of two time slots is introduced. In the first time slot, the DAU broadcasts signals to the relay, and the base station also broadcasts signals to the relay. In the second time slot, the relay decodes the received signals and allocates different relay powers to the base station signals and DAU signals to form a mixed signal, which is then broadcast to licensed users and the gateway. SIC is then performed at the gateway and licensed users based on the signal power allocation.

[0019] In the first time slot, the uplink NOMA receiver relay prioritizes decoding the DAU signal, so the channel capacity of the base station signal and DAU signal received at the relay is:

[0020]

[0021] In the formula, g 1,r =|h BS,r | 2 This represents the channel gain from BS to relay i. W represents the channel gain from DAUi to relay i. i Let R be the bandwidth, N0 represent the variance of the Gaussian noise; i =C i ln2, R i For the actual receiving rate, C i Given the channel capacity, the reception rates of the base station signal and DAU signal received at the relay station are:

[0022]

[0023] In the second time slot, the downlink NOMA receiver performs SIC based on the channel condition power allocation principle; B represents the set of power communication networks implementing the B-SIC scheme, and D represents the set of power communication networks implementing the D-SIC scheme; the B-SIC scheme represents SIC at the licensed user, and the D-SIC scheme represents SIC at the gateway; when the B-SIC scheme is implemented, the receiving rates at the licensed user and the gateway are expressed as:

[0024]

[0025] In the formula, g 1,g,i β represents the channel gain from the base station to the gateway. i I1 represents the relay power allocation coefficient for authorized users when implementing the B-SIC scheme, and I1 represents interference. When implementing the D-SIC scheme, the receiving rates for authorized users and at the gateway are:

[0026]

[0027] In the formula, α i This represents the relay power allocation coefficient for authorized users when implementing the D-SIC scheme.

[0028] A further improvement to the technical solution of the present invention is that the specific steps of step 2 are as follows:

[0029] On the gateway side, due to interference from signals at the same layer and interference from other signals in the mixed signal, and considering that the single capacity of the relay to the gateway should be less than the transmission from the DAU to the relay in order to reliably decode the signal at the relay, if the single capacity of the relay auxiliary transmission is higher than the capacity of the DAU to the relay, the information cannot be fully transmitted; when implementing the B-SCI scheme, the receiving rate constraint of gateway i is:

[0030]

[0031] When implementing the D-SCI scheme, the receive rate constraint for gateway i is:

[0032]

[0033] In the formula, p j g represents the transmit power of DAU j. i,j p represents the channel gain from DAU j to gateway i. j r This represents the transmit power of relay j. This represents the channel gain from relay j to gateway i. This represents the channel gain from DAU j to relay i. This represents the channel gain from relay j to relay i;

[0034] Simplifying the above constraints by scaling them down, we obtain the rate constraint as follows:

[0035]

[0036] At the same time, the maximum transmission rate of the authorized network should exceed the target transmission rate, that is... Assuming the base station's transmit power in the first time slot is high enough to satisfy the condition for complete decoding of licensed network information at the relay point, the licensed network power constraint is obtained:

[0037]

[0038] The relay distributes power to each gateway, subject to the total power. The limitations are thus constrained:

[0039]

[0040] A further improvement of the technical solution of the present invention is that the relay power allocation in step 3 refers to the relay power allocation based on the degree of interference to the communication node.

[0041] A further improvement to the technical solution of the present invention is that step 3 specifically comprises:

[0042] The power company's goal is to achieve optimal relay allocation and minimize total cost. Therefore, we can derive the following sub-problem:

[0043]

[0044] in,

[0045]

[0046]

[0047] P represents the power vector from the relay to the gateway, which can be expressed as:

[0048] Since the objective function is non-convex, a logarithmic approximation is used to transform it into a convex function, and then variable transformation is employed. The subproblem will then be transformed into a convex function maximization problem for the new variable, resulting in the following sub-optimization problem:

[0049]

[0050] The above equation can be solved using the Lagrange duality algorithm to obtain p. i r* And iterate continuously to solve until p i r* convergence.

[0051] A further improvement to the technical solution of this invention lies in the fact that step 4 involves an optimal power ratio allocation, and the optimal power ratio allocation subproblem is expressed as:

[0052]

[0053] Among them, only β i ,α i The optimization variable is the objective function, which is convex. The constraints are linear, so this subproblem is a convex optimization problem. By using standard convex optimization tools, the global optimum of the convex problem can be obtained effectively.

[0054] Due to the adoption of the above technical solution, the technical effects achieved by this invention are as follows:

[0055] This invention, while meeting the Quality of Service (QoS) requirements of the authorized network, employs non-cooperative relay cognitive NOMA technology to improve the transmission rate of the power communication network and reduce the cost for power companies. Under the constraint of QoS requirements of the authorized network, it maximizes the achievable rate of the power communication network, considers in-layer interference and NOMA self-interference, and performs interference management and power allocation on the demand side of the smart grid. This ensures normal authorized network communication services and reduces costs for various power companies. This invention effectively solves the problems of low communication rates and spectrum shortages in the communication process of smart grid demand-side management. Attached Figure Description

[0056] Figure 1 This is a flowchart of the present invention;

[0057] Figure 2 This is a physical architecture diagram of the present invention. Detailed Implementation

[0058] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The described embodiments are merely some embodiments of the present invention, and not all embodiments. 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.

[0059] A method for allocating NOMA spectrum sharing communication resources for smart grids includes: constructing a function relating power company costs to communication rates; quantifying the communication reliability requirements of the licensed network and the power communication network; and allocating communication resources for the communication link between the DAU and the gateway. Figure 1 As shown, the specific steps include:

[0060] Step 1: Construct the function relating power company cost and communication rate, specifically including the construction of the power company cost function and the data transmission rate function at the receiving end during the data transmission process.

[0061] like Figure 2 As shown, the licensed network provides spectrum to the EPC network, and the relays in the EPC network transmit information for the licensed network, thus sharing spectrum resources. Furthermore, the base station sends information to licensed users via downlink transmission in the licensed network, and the control center periodically issues control commands to the gateway via the DAU in the downlink transmission. Assume severe shadowing interference, with no direct connection between the DAU and the gateway, and no direct connection between the base station and the licensed users. When the relay receives information, it constitutes an uplink NOMA system; when the relay transmits information, it constitutes a downlink NOMA system.

[0062] The principle of power allocation based on channel conditions is adopted, that is, the receiver with poor channel conditions is allocated high power and the receiver with good channel conditions is allocated low power, so as to ensure fairness and practicality. Therefore, two schemes have emerged: the SIC scheme is called D-SIC scheme when it is implemented at the gateway, and the SIC scheme is called B-SIC scheme when it is implemented at the authorized user.

[0063] The Taguchi loss function (TLF) is introduced to describe the cost characteristics of utility companies. The cost of each utility company can be expressed as:

[0064]

[0065] Where ξ represents the increase in variance due to the loss of a single data packet. χ represents the variance without packet loss, where χ is a constant. s Indicates a sampling period. This is the retention cost for power company i, R i This is the actual transmission rate of DAU i. It is the target transmission rate.

[0066] To improve spectrum utilization, NOMA technology is employed to provide services to both the EPC network and the licensed network simultaneously. It is assumed that each node has perfect channel state information. A decode-forward (DF) relay strategy consisting of two time slots is introduced. In the first time slot, the DAU broadcasts signals to the relay, and the base station also broadcasts signals to the relay. In the second time slot, the relay decodes the received signals and distributes the base station signal and DAU signal with different relay powers to form a mixed signal, which is then broadcast to licensed users and the gateway. SIC (Separate Interchange Component) is then performed at the gateway and licensed users based on the signal power distribution.

[0067] In the first time slot, the uplink NOMA receiver relay prioritizes decoding the DAU signal, so the channel capacity of the base station signal and DAU signal received at the relay is:

[0068]

[0069] In the formula, g 1,r =|h BS,r | 2 This represents the channel gain from BS to relay i. W represents the channel gain from DAU i to relay i. i Let R be the bandwidth, and N0 represent the variance of the Gaussian noise. For ease of subsequent derivation, let R be... i =C i ln2, R i For the actual receiving rate, C i Let be the channel capacity. Therefore, the reception rates of the base station signal and DAU signal received at the relay station are:

[0070]

[0071] In the second time slot, the downlink NOMA receiver performs SIC based on channel condition power allocation. B represents the set of power communication networks implementing the B-SIC scheme, and D represents the set of power communication networks implementing the D-SIC scheme. The B-SIC scheme represents SIC at the licensed user, and the D-SIC scheme represents SIC at the gateway. When the B-SIC scheme is implemented, the receive rates at the licensed user and the gateway are expressed as:

[0072]

[0073] In the formula, g 1,g,i β represents the channel gain from the base station to the gateway. i This represents the relay power allocation coefficient for authorized users when implementing the B-SIC scheme, with I1 representing interference. When implementing the D-SIC scheme, the receive rates for authorized users and at the gateway are:

[0074]

[0075] In the formula, α i This represents the relay power allocation coefficient for authorized users when implementing the D-SIC scheme.

[0076] Step 2: Quantify the communication reliability requirements of the authorized network and the power communication network, mainly to ensure the network service quality of the authorized network and to ensure that the relay can fully decode and forward information.

[0077] On the gateway side, due to interference from signals at the same layer and interference from other signals in the mixed signal, and considering that the single capacity of the relay to the gateway should be less than the transmission from the DAU to the relay in order to reliably decode the signal at the relay, if the single capacity of the relay auxiliary transmission is higher than the capacity of the DAU to the relay, the information cannot be fully transmitted. When implementing the B-SCI scheme, the receiving rate constraint of gateway i is:

[0078]

[0079] When implementing the D-SCI scheme, the receive rate constraint for gateway i is:

[0080]

[0081] In the formula, p j g represents the transmit power of DAU j. i,j p represents the channel gain from DAU j to gateway i. j r This represents the transmit power of relay j. This represents the channel gain from relay j to gateway i. This represents the channel gain from DAU j to relay i. This represents the channel gain from relay j to relay i.

[0082] Simplifying the above constraints by scaling them down, we obtain the rate constraint as follows:

[0083]

[0084] At the same time, the maximum transmission rate of the authorized network should exceed the target transmission rate, that is... Assuming the base station's transmit power in the first time slot is high enough to satisfy the condition for complete decoding of licensed network information at the relay point, the licensed network power constraint is obtained:

[0085]

[0086] The relay distributes power to each gateway, which is subject to the total power. The constraints are thus derived:

[0087]

[0088] In a two-layer network environment, the power line communication network provides relay forwarding services to the licensed network, ensuring the quality of service for the licensed network and thus securing spectrum usage rights from the licensed network. Assuming the two layers are densely distributed, interference will occur between the power line communication network and the licensed network, and there will also be in-layer interference between the power line communication networks themselves. Introducing NOMA technology improves relay forwarding efficiency and reduces mutual interference. Therefore, the radio resource management problem can be formulated as follows:

[0089]

[0090] Step 3: Perform power allocation for relay nodes

[0091] Relay power allocation refers to the allocation of relay power based on the degree of interference to communication nodes, which reduces interference in two-layer networks and lowers the costs for power companies.

[0092] The power company's goal is to achieve optimal relay allocation and minimize total cost. Therefore, the following sub-problem can be derived:

[0093]

[0094] in

[0095]

[0096]

[0097] P represents the power vector from the relay to the gateway, which can be expressed as:

[0098] Since the objective function is non-convex, a logarithmic approximation is used to transform it into a convex function, and then variable transformation is employed. The subproblem will then be transformed into a convex function maximization problem for the new variable, resulting in the following sub-optimization problem:

[0099]

[0100] The above equation can be solved using the Lagrange duality algorithm to obtain p. i r* And iterate continuously to solve until p i r* convergence.

[0101] Step 4: Perform power allocation for downlink NOMA

[0102] Downlink NOMA power allocation refers to increasing the communication rate of the power network and reducing the cost for the power company while ensuring the quality of communication services of the licensed network.

[0103] The optimal power ratio allocation subproblem can be expressed as:

[0104]

[0105] Please note that this subproblem only contains β. i ,α i The variables are optimization variables, and the objective function is convex. The constraints are linear, so this subproblem is a convex optimization problem. The global optimum of a convex problem can be efficiently obtained using standard convex optimization tools.

[0106] The optimal power allocation and power allocation coefficients are obtained by jointly iteratively solving the two subproblems.

[0107] The system disclosed in the embodiments is described in a relatively simple manner because it corresponds to the method disclosed in the embodiments. For relevant details, please refer to the method section.

[0108] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A NOMA spectrum sharing communication resource allocation method for smart grids, characterized in that, Includes the following steps: Step 1: Constructing the function relating power company costs to communication rates; Step 2: Quantify the communication reliability requirements of the authorized network and the power communication network; the specific steps of Step 2 are as follows: On the gateway side, due to interference from signals at the same layer and interference from other signals in the mixed signal, and considering that the single capacity of the relay to the gateway should be less than the transmission from the DAU to the relay in order to reliably decode the signal at the relay, if the single capacity of the relay auxiliary transmission is higher than the capacity of the DAU to the relay, the information cannot be fully transmitted; when SIC is implemented at the authorized user, which is called the B-SIC scheme, the receiving rate constraint of gateway i is: In the formula, This represents the channel gain from the base station to the gateway. For bandwidth, This represents the channel gain from DAUi to relay i. This represents the channel gain from BS to relay i. The variance of Gaussian noise is represented. This represents the relay power allocation factor for authorized users when implementing the B-SIC scheme. The transmit power of DAUj is represented. This represents the channel gain from DAU j to gateway i. This represents the transmit power of relay j. This represents the channel gain from relay j to gateway i. This represents the channel gain from DAU j to relay i. This represents the channel gain from relay j to relay i; When SIC is performed at the gateway, known as the D-SIC scheme, the receive rate constraint of gateway i is: In the formula, This represents the relay power allocation factor for authorized users when implementing the D-SIC scheme; When implementing the D-SCI scheme, the above constraints can be simplified to obtain the rate constraint condition as follows: Meanwhile, the maximum transmission rate of the authorized network should exceed the target transmission rate. Assuming that the base station's transmit power in the first time slot is large enough to meet the condition of completely decoding the authorized network information at the relay point, the authorized network power constraint is obtained: The relay distributes power to each gateway, subject to the total power. The limitations are thus constrained: ； Step 3: Perform power allocation for relay nodes; Step 3 specifically involves: The power company's goal is to achieve optimal relay allocation and minimize total cost. Therefore, we can derive the following sub-problem: in, P represents the power vector from the relay to the gateway, which can be expressed as: ; Since the objective function is non-convex, a logarithmic approximation is used to transform it into a convex function, and then variable transformation is employed. The subproblem will then be transformed into a convex function maximization problem for the new variable, resulting in the following sub-optimization problem: The above equation can be solved using the Lagrange duality algorithm. And continuously iterate to solve until convergence; Step 4: Perform downlink NOMA power allocation; Step 4 has an optimal power allocation, and the optimal power allocation subproblem is expressed as: Of these, only The optimization variable is the objective function, which is convex. The constraints are linear, so this subproblem is a convex optimization problem. By using standard convex optimization tools, the global optimal solution to the convex problem can be obtained effectively.

2. The NOMA spectrum sharing communication resource allocation method for smart grids according to claim 1, characterized in that: Step 1 includes constructing the power company's cost function and the data transmission rate function at the receiving end during the data transmission process, specifically: The licensed network provides spectrum to the EPC network, and the relays in the EPC network transmit information for the licensed network, thus sharing spectrum resources. The base station sends information to licensed users through downlink transmission in the licensed network, and the control center periodically issues control commands to the gateway through the DAU in the downlink transmission. Assume that there is severe shadow interference, there is no direct connection between the DAU and the gateway, and there is also no direct connection between the base station and the licensed users. When the relay receives information, it constitutes an uplink NOMA system, and when the relay sends information, it constitutes a downlink NOMA system. The principle of power allocation based on channel conditions is adopted, that is, high power is allocated to receivers with poor channel conditions and low power is allocated to receivers with good channel conditions. Therefore, two schemes are generated: SIC is implemented at the gateway and is called D-SIC scheme, and SIC is implemented at authorized users and is called B-SIC scheme. The Taguchi loss function is introduced to describe the cost characteristics of utility companies. The cost of each utility company can be expressed as: In the formula, This indicates the increase in variance due to the loss of a single data packet. This indicates the variance of no packet loss. It is a constant. Indicates a sampling period. It is the retention cost of power company i. This is the actual transmission rate of DAU i. It is the target transmission rate; To improve spectrum utilization, NOMA technology is used to provide services to both the EPC network and the licensed network simultaneously. Assuming that each node has perfect channel state information, a decode-forward relay strategy consisting of two time slots is introduced. In the first time slot, the DAU broadcasts signals to the relay, and the base station also broadcasts signals to the relay. In the second time slot, the relay decodes the received signals and allocates different relay powers to the base station signals and DAU signals to form a mixed signal, which is then broadcast to licensed users and the gateway. SIC is then performed at the gateway and licensed users based on the signal power allocation. In the first time slot, the uplink NOMA receiver relay prioritizes decoding the DAU signal, so the channel capacity of the base station signal and DAU signal received at the relay is: remember , This represents the actual receiving rate. Given the channel capacity, the reception rates of the base station signal and DAU signal received at the relay station are: In the second time slot, the receiver of downlink NOMA performs SIC based on the channel condition power allocation principle; This represents the set of power communication networks implementing the B-SIC scheme. This represents the set of power communication networks that implement the D-SIC scheme; The B-SIC scheme represents SIC at the authorized user's location, while the D-SIC scheme represents SIC at the gateway. When the B-SIC scheme is executed, the receiving rates at the authorized user and the gateway are expressed as follows: In the formula, This represents the channel gain from the base station to the gateway; when implementing the D-SIC scheme, the receive rates for licensed users and at the gateway are: In the formula, This represents the relay power allocation coefficient for authorized users when implementing the D-SIC scheme.

3. The NOMA spectrum sharing communication resource allocation method for smart grids according to claim 1, characterized in that: The relay power allocation in step 3 refers to the relay power allocation based on the degree of interference to the communication node.

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