CN113923745B - Communication relay selection method and communication method of electric power communication system - Google Patents

Abstract

The invention discloses a communication relay selection method of a power communication system, which includes acquiring real-time parameters of the power communication system in an area to be analyzed; taking the distance between a target D2D terminal and a base station as the diameter, and taking the distance between the target D2D terminal and the base station as the diameter The midpoint of the connecting line segment is the center of the circle to construct a relay selection area; judge whether there are relay nodes in the relay selection area; divide several concentric circles in the relay selection area and obtain several sub-areas; select A sub-area where there are relay nodes; select a relay node for signal relay, and complete the communication relay selection of the power communication system. The invention also discloses a communication method including the communication relay selection method of the power communication system. The invention greatly reduces the complexity of the system and the overall cost of the system, and has better performance in the reliability and safety of signal transmission, and has wider application range and better practicability.

Description

Communication relay selection method and communication method of electric power communication system

technical field

The invention belongs to the technical field of power grid communication, and in particular relates to a method for selecting a communication relay in a power communication system and a communication method thereof.

Background technique

With the development of economy and technology and the improvement of people's living standards, electric energy has been widely used in people's production and life, bringing endless convenience to people's production and life. Therefore, ensuring a stable and reliable supply of electric energy has become one of the most important tasks of the power system.

The power communication system is an important part of the power system. The efficient operation of typical power services (such as distribution network automation, power consumption information collection, distributed power supply, precise load control, power emergency communication, etc.) is inseparable from the support of power communication systems. At this stage, the communication bearer network for electric power services is generally composed of a wired optical fiber private network and an eLTE power wireless private network; with the application and promotion of the fifth generation mobile communication technology (5G), the electric power communication network will also be compatible with the 5G network.

Device to Device (D2D) technology is one of the key technologies of 5G, which enables a terminal to directly exchange data with neighboring devices without going through a base station. D2D technology can significantly improve spectrum utilization, increase network capacity, and reduce signaling overhead between terminals and base stations. Therefore, the power communication system will inevitably have more and more communication terminals connected to the 5G network.

However, most of the power communication terminals connected to the 5G network are in fixed positions, such as distribution network automation distributed terminals, household power consumption information collection terminals, power transmission and transformation status monitoring terminals, etc., and the coverage of 5G base stations is limited, so there must be some 5G base stations cover power communication terminals at the edge. These power communication terminals will not be able to directly establish contact with the base station or the reliability of data transmission with the base station will not be guaranteed when the wireless environment is relatively harsh. At this time, a relay link can be established with the help of D2D communication technology to improve the communication quality of the power communication terminal, thereby ensuring the reliable transmission of power data.

At present, the commonly used D2D relay selection methods mainly include the following: 1) Relay selection method based on channel quality: D2D terminal detects the channel quality of each D2D communication link of relay terminal, and selects the relay terminal with the highest channel quality; 2) Relay selection method based on D2D neighbor terminal list: each D2D terminal pre-builds a neighbor terminal list for D2D communication, and D2D terminal dynamically updates the neighbor terminal according to a predetermined strategy. The priority ordering of the terminal list, when D2D relay communication is required, the D2D terminal selects the terminal with the highest priority in the list as the relay terminal; 3) Dynamic D2D relay selection method based on relative speed: consider the potential relay terminal The direction of future movement between the two and the relative speed with the D2D terminal, and the terminal with the highest contact stability with the D2D terminal is selected as the relay terminal to improve the stability of relay selection; 4) Network coding-assisted multi-pair D2D communication relay selection method: Jointly consider the relay location, communication content, remaining energy and system capacity, and use this as the basis for relay selection; 5) Optimal relay selection strategy based on Q-learning method: update D2D users with the help of Q-learning algorithm in reinforcement learning The correct Q table, after many iterations, the Q table converges; and according to the Q table, select the best relay.

However, the above-mentioned relay selection methods are all based on the assumption that the D2D terminal can obtain as many accurate information of the relay terminal as possible; therefore, the above-mentioned methods all have relatively large feedback overhead and relatively complex system complexity. Moreover, in the actual network environment, due to estimation errors or feedback limitations, D2D terminals are often unable to obtain accurate terminal location and related status information. Therefore, the above-mentioned relay selection methods have problems such as poor practicability and limited scope of application. .

Contents of the invention

One of the objectives of the present invention is to provide a communication relay selection method for a power communication system with low system complexity, low overall system overhead, wide application range and good practicability.

The second object of the present invention is to provide a communication method including the communication relay selection method of the power communication system.

The communication relay selection method of the power communication system provided by the present invention includes the following steps:

S1. Obtain real-time parameters of the power communication system in the area to be analyzed;

S2. Taking the distance between the target D2D terminal and the base station as the diameter, and taking the midpoint of the line segment between the target D2D terminal and the base station as the center, construct a relay selection area;

S3. Determine whether there is a relay node in the relay selection area constructed in step S2:

If there is no relay node, the target D2D terminal communicates directly with the base station, and the algorithm ends;

If there is a relay node, proceed to the next step;

S4. In the relay selection area constructed in step S2, take the midpoint of the line segment between the target D2D terminal and the base station as the center of the circle, and divide several concentric circles, thereby dividing the relay selection area constructed in step S2 into several sub-regions;

S5. Among the several sub-areas divided in step S4, select a sub-area in which relay nodes exist;

S6. In the sub-area selected in step S5, select a relay node for signal relay, thereby completing the communication relay selection of the electric power communication system.

In the relay selection area constructed in step S2 described in step S4, the midpoint of the line segment between the target D2D terminal and the base station is used as the center point to divide several concentric circles, so that the relay selection area constructed in step S2 Divide into several sub-areas, specifically including the following steps:

A. In the relay selection area, set the relay node closest to the center of the circle as the best relay node;

B. When the best relay node selected in step A is used for relay transmission, the following formula is used to calculate the best communication reliability gain ε _best :

λ_r为区域A内单位面积的平均中继数量，|A|为区域A的面积；/>

表示在中继选择区域中存在k个中继节点时，选择最佳中继节点进行中继传输时可获得的可靠性增益，且/>

R为中继选择区域的半径，d_s为坐标(x_s,y_s)与坐标(x_d,y_d)之间的距离，μ为中间变量，且

Γ_s为D2D终端所需的SIR门限值，α为一般幂律路径损耗模型的损耗指数，η_th为非D2D终端接收信号的干扰门限值，λ_s为D2D终端的密度，λ_p为基站密度，d_p为非D2D终端与对应的通信基站的距离，Γ_p为中继选择区域中其他非D2D终端的SIR门限值；In the formula, Pr(N(A)=k) is the Poisson probability that there are k relays in area A, and the calculation formula of Pr(N(A)=k) is

λ _r is the average number of relays per unit area in area A, |A| is the area of area A; />

Indicates the reliability gain that can be obtained when selecting the best relay node for relay transmission when there are k relay nodes in the relay selection area, and />

R is the radius of the relay selection area, d _s is the distance between coordinates (x _s , y _s ) and coordinates (x _d , y _d ), μ is an intermediate variable, and

Γ _s is the SIR threshold value required by D2D terminals, α is the loss exponent of the general power-law path loss model, η _th is the interference threshold value of non-D2D terminals receiving signals, λ _s is the density of D2D terminals, λ _p is Base station density, d _p is the distance between the non-D2D terminal and the corresponding communication base station, Γ _p is the SIR threshold value of other non-D2D terminals in the relay selection area;

C. Use the following formula to calculate the communication reliability gain ε _region (L):

λ_r为区域A内单位面积的平均中继数量，|A|为区域A的面积；/>

为在中继选择区域中存在k个中继节点时，采用本发明方法选择中继节点进行中继传输时可获得的可靠性增益，且

In the formula, Pr(N(A)=k) is the Poisson probability that there are k relays in area A, and the calculation formula of Pr(N(A)=k) is

λ _r is the average number of relays per unit area in area A, |A| is the area of area A; />

When there are k relay nodes in the relay selection area, the reliability gain that can be obtained when the method of the present invention is used to select the relay node for relay transmission, and

为组合数公式/>

i代表第i个圆环；Ψ(x)为单个第n最佳中继的可靠性增益计算函数，且/>

j代表中继选择区域内第n最佳中继节点向外延伸的第j个中继节点，γ(A,B)为不完全伽马函数；m is the number of relay nodes in the ring that is closest to the center of the circle and there are relay nodes; n indicates that the relay node selected when selecting a relay node for transmission is the nth closest to the center of the circle among all relay nodes Relay node; L is the index number of divided concentric circles;

For the combination number formula />

i represents the i-th ring; Ψ(x) is the reliability gain calculation function of a single n-th best relay, and />

j represents the jth relay node extending outward from the nth best relay node in the relay selection area, and γ(A, B) is an incomplete gamma function;

D. Set the ratio β between the available communication reliability gain ε _region (L) and the best communication reliability gain ε _best , and use the formula ε _region (L) = β · ε _best to obtain the divided The exponent L of the concentric circles;

E. According to the number L of divided concentric circles obtained in step D, finally divide the relay selection area into 2 ^L concentric circles with equal adjacent areas.

In step S5, among the several sub-regions divided in step S4, selecting a sub-region in which relay nodes exist, specifically includes the following steps:

Among the several sub-regions divided in step S4, the sub-region closest to the center of the circle and having relay nodes is selected.

In the sub-area selected in step S5 described in step S6, selecting a relay node for signal relay specifically includes the following steps:

In the sub-area selected in step S5, if there is only one relay node, then directly select the relay node for signal relay;

In the sub-area selected in step S5, if there are several relay nodes, randomly select a relay node among the several relay nodes to perform signal relay.

The present invention also discloses a communication method including the communication relay selection method of the power communication system, which also includes the following steps:

S7. Perform data transmission in the power communication system according to the relay node selected in step S6, thereby completing data communication in the power communication system.

The communication relay selection method and communication method of the power communication system provided by the present invention do not need to obtain accurate relay terminal location and other information, but only need to select an optimal relay node in the defined area To assist D2D terminals in communication and data transmission; therefore, the present invention greatly reduces the complexity of the system and the overall overhead of the system, and has better performance in terms of reliability and security of signal transmission, and has a wider scope of application , better practicality.

Description of drawings

FIG. 1 is a schematic flow chart of the relay selection method of the present invention.

FIG. 2 is a schematic flow chart of the communication method of the present invention.

Detailed ways

As shown in Figure 1, it is a schematic flow chart of the relay selection method of the present invention: the communication relay selection method of the power communication system provided by the present invention includes the following steps:

S1. Obtain real-time parameters of the power communication system in the area to be analyzed;

S2. Taking the distance between the target D2D terminal and the base station as the diameter, and taking the midpoint of the line segment between the target D2D terminal and the base station as the center, construct a relay selection area;

为圆心，以/>

为半径作圆，并作为中继选择区域；其中

d_s为坐标(x_s,y_s)与坐标(x_d,y_d)之间的距离；During specific implementation, when a D2D terminal with coordinates (x _s , y _s ) communicates with a base station with coordinates (x _d , y _d ), the coordinates will be

as the center of the circle, with />

Draw a circle for the radius and select the area as a trunk; where

d _s is the distance between coordinates (x _s , y _s ) and coordinates (x _d , y _d );

S3. Determine whether there is a relay node in the relay selection area constructed in step S2:

If there is no relay node, the target D2D terminal communicates directly with the base station, and the algorithm ends;

If there is a relay node, proceed to the next step;

S4. In the relay selection area constructed in step S2, take the midpoint of the line segment between the target D2D terminal and the base station as the center of the circle, and divide several concentric circles, thereby dividing the relay selection area constructed in step S2 into several sub-regions; specifically, the following steps are included:

A. In the relay selection area, set the relay node closest to the center of the circle as the best relay node;

B. When the best relay node selected in step A is used for relay transmission, the following formula is used to calculate the best communication reliability gain ε _best :

λ_r为区域A内单位面积的平均中继数量，|A|为区域A的面积；/>

表示在中继选择区域中存在k个中继节点时，选择最佳中继节点进行中继传输时可获得的可靠性增益，且/>

R为中继选择区域的半径，d_s为坐标(x_s,y_s)与坐标(x_d,y_d)之间的距离，μ为中间变量，且

Γ_s为D2D终端所需的SIR门限值，α为一般幂律路径损耗模型的损耗指数，η_th为非D2D终端接收信号的干扰门限值，λ_s为D2D终端的密度，λ_p为基站密度，d_p为非D2D终端与对应的通信基站的距离，Γ_p为中继选择区域中其他非D2D终端的SIR门限值；In the formula, Pr(N(A)=k) is the Poisson probability that there are k relays in area A, and the calculation formula of Pr(N(A)=k) is

λ _r is the average number of relays per unit area in area A, |A| is the area of area A; />

Indicates the reliability gain that can be obtained when selecting the best relay node for relay transmission when there are k relay nodes in the relay selection area, and />

R is the radius of the relay selection area, d _s is the distance between coordinates (x _s , y _s ) and coordinates (x _d , y _d ), μ is an intermediate variable, and

Γ _s is the SIR threshold value required by D2D terminals, α is the loss exponent of the general power-law path loss model, η _th is the interference threshold value of non-D2D terminals receiving signals, λ _s is the density of D2D terminals, λ _p is Base station density, d _p is the distance between the non-D2D terminal and the corresponding communication base station, Γ _p is the SIR threshold value of other non-D2D terminals in the relay selection area;

C. Use the following formula to calculate the communication reliability gain ε _region (L):

λ_r为区域A内单位面积的平均中继数量，|A|为区域A的面积；/>

为在中继选择区域中存在k个中继节点时，采用本发明方法选择中继节点进行中继传输时可获得的可靠性增益，且In the formula, Pr(N(A)=k) is the Poisson probability that there are k relays in area A, and the calculation formula of Pr(N(A)=k) is

λ _r is the average number of relays per unit area in area A, |A| is the area of area A; />

When there are k relay nodes in the relay selection area, the reliability gain that can be obtained when the method of the present invention is used to select the relay node for relay transmission, and

为组合数公式/>

i代表第i个圆环；Ψ(x)为单个第n最佳中继的可靠性增益计算函数，且/>

j代表中继选择区域内第n最佳中继节点向外延伸的第j个中继节点，γ(A,B)为不完全伽马函数；m is the number of relay nodes in the ring that is closest to the center of the circle and there are relay nodes; n indicates that the relay node selected when selecting a relay node for transmission is the nth closest to the center of the circle among all relay nodes Relay node; L is the index number of divided concentric circles;

For the combination number formula />

i represents the i-th ring; Ψ(x) is the reliability gain calculation function of a single n-th best relay, and />

j represents the jth relay node extending outward from the nth best relay node in the relay selection area, and γ(A, B) is an incomplete gamma function;

D. Set the ratio β between the available communication reliability gain ε _region (L) and the best communication reliability gain ε _best , and use the formula ε _region (L) = β · ε _best to obtain the divided The exponent L of the concentric circles;

E. According to the index quantity L of the divided concentric circles obtained in step D, the relay selection area is finally divided into 2 ^L concentric circles with equal areas of adjacent rings;

During specific implementation, it has been verified that when L takes an empirical value of 2, 90% reliability gain of the best relay can be obtained;

S5. Among the several sub-regions divided in step S4, select a sub-region in which relay nodes exist; specifically include the following steps:

Among the several sub-regions divided in step S4, select the sub-region closest to the center of the circle and having relay nodes;

S6. In the sub-area selected in step S5, select a relay node to carry out signal relay, thereby completing the communication relay selection of the power communication system; specifically include the following steps:

In the sub-area selected in step S5, if there is only one relay node, then directly select the relay node for signal relay;

In the sub-area selected in step S5, if there are several relay nodes, randomly select a relay node among the several relay nodes to perform signal relay.

As shown in Figure 2, it is a schematic flow chart of the communication method of the present invention: the communication method provided by the present invention that includes the communication relay selection method of the power communication system also includes the following steps:

S7. Perform data transmission in the power communication system according to the relay node selected in step S6, thereby completing data communication in the power communication system.

Claims (4)

1. A communication relay selection method of an electric power communication system includes the following steps:

s1, acquiring real-time parameters of a power communication system in an area to be analyzed;

s2, constructing a relay selection area by taking the distance between the target D2D terminal and the base station as the diameter and taking the midpoint of a line segment of a connecting line between the target D2D terminal and the base station as the center of a circle;

s3, judging whether a relay node exists in the relay selection area constructed in the step S2:

if the relay node does not exist, the target D2D terminal directly communicates with the base station, and the algorithm is ended;

if the relay node exists, continuing to carry out the subsequent steps;

s4, in the relay selection area constructed in the step S2, dividing a plurality of concentric circles by taking the midpoint of a line segment of a connecting line between the target D2D terminal and the base station as a circle center, so that the relay selection area constructed in the step S2 is divided into a plurality of sub-areas; the method specifically comprises the following steps:

A. setting a relay node closest to a circle center as an optimal relay node in a relay selection area;

B. and C, when the best relay node selected in the step A is used for relay transmission, calculating the best communication reliability gain epsilon by adopting the following formula _best ：

Where Pr (N (a) =k) is Poisson probability that there are k relays in the region a, and the calculation formula of Pr (N (a) =k) is

λ _r The average relay number of unit area in the area A is shown, and the I A I is the area of the area A; />

Indicating the reliability gain obtainable when selecting the best relay node for relay transmission when there are k relay nodes in the relay selection area, and +.>

R is the radius of the relay selection area, d _s For D2D terminal coordinates (x _s ,y _s ) Coordinate with base station (x _d ,y _d ) The distance between them, μ is an intermediate variable, and +.>

Γ _s For the SIR threshold required for D2D terminals, α is the loss index, η of the general power law path loss model _th Interference threshold value lambda for receiving signal of non-D2D terminal _s For the density of D2D terminals lambda _p For the base station density d _p Is the distance Γ between the non-D2D terminal and the corresponding communication base station _p Selecting SIR threshold values of other non-D2D terminals in the area for the relay;

C. the communication reliability gain epsilon is calculated by the following formula _region (L)：

Where Pr (N (a) =k) is Poisson probability that there are k relays in the region a, and the calculation formula of Pr (N (a) =k) is

λ _r The average relay number of unit area in the area A is shown, and the I A I is the area of the area A; />

When k relay nodes exist in the relay selection area, the method of the invention is adopted to select the reliability gain which can be obtained when the relay nodes perform relay transmission, and

m is the number of relay nodes in the ring closest to the center of the circle and having the relay nodes; n represents that the selected relay node is the nth closest to the center of the circle in all the relay nodes when the relay nodes are selected for transmissionIs a relay node of (a); l is the index number of the divided concentric circles; />

For the combination number formula->

i represents the ith ring; ψ (x) is the reliability gain calculation function of the single nth best relay, and +.>

j represents a j-th relay node extending outwards from an n-th best relay node in the relay selection area, and gamma (A, B) is an incomplete gamma function;

D. setting an acquirable communication reliability gain epsilon _region (L) gain ε of reliability of communication with optimum _best Beta ratio between them and through the formula epsilon _region (L)＝β·ε _best Reversely pushing to obtain the index L of the divided concentric circles;

E. and D, dividing the relay selection area into 2 according to the index L of the divided concentric circles obtained in the step D ^L Concentric circles with equal areas of adjacent circular rings;

s5, selecting one subarea with the relay node from a plurality of subareas divided in the step S4;

s6, selecting one relay node to relay signals in the subarea selected in the step S5, so that communication relay selection of the power communication system is completed.

2. The communication relay selection method of the power communication system according to claim 1, wherein in the plurality of sub-areas divided in step S4 in step S5, one sub-area having a relay node is selected, and specifically comprising the steps of:

and selecting a subarea which is closest to the center of a circle and has a relay node from a plurality of subareas divided in the step S4.

3. The communication relay selection method of the power communication system according to claim 2, wherein in the sub-area selected in step S5, in step S6, a relay node is selected to relay signals, and the method specifically comprises the following steps:

in the sub-area selected in the step S5, if only one relay node exists, the relay node is directly selected for signal relay;

in the sub-area selected in step S5, if there are several relay nodes, randomly selecting one relay node from the several relay nodes to relay the signal.

4. A communication method including the communication relay selection method of the power communication system according to any one of claims 1 to 3, characterized by further comprising the steps of:

s7, carrying out data transmission of the power communication system according to the relay node selected in the step S6, thereby completing data communication of the power communication system.

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