Relay-assisted D2D communication performance grade evaluation method under emergency condition

Abstract

A relay-assisted D2D communication performance grade evaluation method under an emergency condition belongs to the technical field of 5G communication, and comprises a relay-assisted D2D communication data acquisition method, a coverage grade evaluation method, a throughput grade evaluation method, a time delay grade evaluation method, an anti-interference grade evaluation method and a relay-assisted D2D communication performance comprehensive scoring method. According to the method, comprehensive, accurate and visual evaluation is carried out on the evaluation target performance from the five aspects of coverage, throughput, time delay, anti-interference capability and comprehensive performance, and the problems of single evaluation index and lack of pertinence in the prior art are solved.

Description

Technical Field

[0001] The present invention belongs to the field of 5G communication technology, and in particular relates to a method for evaluating the performance level of relay-assisted D2D communications under emergency conditions. Background Art

[0002] With the rapid development of mobile communication technology, wireless communication quality has become more and more reliable and efficient. However, in the event of major natural disasters or man-made emergencies, traditional communication infrastructure may be damaged or interrupted, resulting in the inability of communication networks to operate normally. In order to meet the needs of emergency communications, it is necessary to find a reliable and flexible communication method.

[0003] As one of the key technologies of 5G communication, D2D (Device-to-Device, also known as terminal direct communication) communication technology has the advantages of direct communication between devices, low latency and high reliability, providing a new solution for emergency communication. However, the coverage of basic D2D communication is limited and the communication distance is short, which cannot meet the communication needs of a large range. Therefore, relay-assisted D2D communication technology is introduced into the emergency communication network.

[0004] In order to fully understand the performance of relay-assisted D2D communication under emergency conditions, the coverage, throughput, latency and anti-interference ability of D2D relay communication are evaluated. Such an evaluation can provide a scientific basis for the planning and optimization of emergency communication networks, help establish a fast, reliable and stable communication network, and thus improve the efficiency of rescue work.

[0005] The current D2D communication performance evaluation methods mainly have the following problems:

[0006] (1) Lack of comprehensive performance indicators: Some evaluation methods may only focus on a single performance indicator and fail to fully consider the trade-offs and comprehensive effects between multiple performance indicators. This may result in the evaluation results not being able to fully reflect the comprehensive performance of D2D communications.

[0007] (2) Lack of specificity for special scenarios: Some evaluation methods may only be applicable to ideal conditions or common scenarios, and lack specificity for damaged or failed communication equipment, such as macro base stations and terminal equipment. This makes the evaluation results lack specificity for special scenarios. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide a method for evaluating the performance level of relay-assisted D2D communication under emergency conditions, which makes a comprehensive, accurate and intuitive evaluation of the evaluation target performance from five aspects: coverage, throughput, latency, anti-interference capability and comprehensive performance, and solves the problems of single evaluation indicators and lack of specificity in the prior art.

[0009] A method for evaluating the performance level of relay-assisted D2D communication under emergency conditions comprises the following steps:

[0010] Step 1: Obtain relay-assisted D2D communication data, including the macro base station coverage R BS , the distance R from the macro base station to the relay node BD , the base station's transmission power is P B , assuming that there are n users with D2D devices in the emergency communication area, and the distance from the i-th user to the relay node is D i , i = 1, 2, ···, n, the relay node transmission power is P, there are m cellular users within the coverage of the macro base station, and the distance from the jth cellular user to the relay node is D cj , j = 1, 2, ···, m, the average transmission power of m cellular users is The transmission and reception gain of the D2D device is G, and the channel gain of the communication within the coverage area of ​​the macro base station is G c , the path loss factor is α, and the wireless signal frequency f is 2400MHz, the loss factor of the kth layer obstacle material is a k The value is 0.463-0.464dB / cm. The communication mode between n users and the relay node is D2D communication. The uplink rate from the i-th user to the relay node is v ui , the average uplink rate from n users to the relay node is The downlink rate from the relay node to the i-th user is ν di , the average downlink rate from the relay node to n users is Channel utilization rate of relay node η D , the channel utilization rate of the macro base station η B , the transmission delay of the D2D device is t s , the propagation delay without penetrating the obstacle is t c , the queuing delay is t l , the processing delay is t d , the average delay from macro base station to cellular users within the coverage area of ​​macro base station is

[0011] Step 2: According to the relay node coverage radius and the distance from the macro base station to the relay node, establish the relay node coverage range evaluation index Z1, and define the relay node coverage range level W1 according to the size of Z1; according to the relay node throughput and the throughput of the macro base station, establish the relay node throughput evaluation index Z2, and define the relay node throughput level W2 according to the size of Z2; according to the communication delay and the average delay from the macro base station to the cellular users within the coverage range of the macro base station, establish the relay node delay evaluation index Z3, and define the relay node delay level W3 according to the size of Z3; according to the signal to noise ratio of the relay node and the signal to noise ratio of the jth cellular user, establish the relay node anti-interference evaluation index Z4, and define the relay node anti-interference level W4 according to the size of Z4;

[0012] Step 3: Calculate the relay node comprehensive score W according to the relay node coverage level W1, relay node throughput level W2, relay node delay level W3, and relay node anti-interference level W4 described in step 2:

[0013] W=λ1·W1+λ2·W2+λ3·W3+λ4·W4

[0014] Among them, λ1 is the weight of the relay node’s coverage level, λ2 is the weight of the relay node’s throughput level, λ3 is the weight of the relay node’s delay level, and λ4 is the weight of the relay node’s anti-interference level. The value range is (0,1), λ1+λ2+λ3+λ4=1, and the default value is When 0.125≤W<0.25, the performance of the relay node is regarded as level three, when 0.25<W≤0.5, the performance of the relay node is regarded as level two, and when 0.5<W≤1, the performance of the relay node is regarded as level one.

[0015] The coverage level W1 of the relay node in step 2 is defined as follows:

[0016] The path loss from the user to the relay node PLOSS includes the propagation loss of the wireless signal in the air P free and the propagation loss of wireless signals through obstacles P ruin , expressed as:

[0017] PLOSS=P free +P ruin

[0018] Wireless signal propagation loss in the air free It is expressed as:

[0019]

[0020] In the formula, c is the speed of light, and f is the frequency of the wireless signal;

[0021] The propagation loss of wireless signals penetrating obstacles P ruin for:

[0022]

[0023] In the formula, a k represents the loss factor of the k-th obstacle material, h k represents the thickness of the kth layer of obstacles, and N is the total number of penetrating obstacles;

[0024] The path loss PLOSS from the user to the relay node is reformulated as:

[0025]

[0026] By default, the relay node is located at the edge of the macro base station, and the coverage radius R of the relay node is expressed as:

[0027]

[0028] The relay node coverage evaluation index Z1 is:

[0029]

[0030] According to the size of Z1, the coverage level W1 of the relay node is defined as:

[0031]

[0032] The relay node throughput level W2 evaluation method described in step 2 is:

[0033] The average uplink rate from n users to the relay node is Affected by obstacles, the average uplink rate is reduced. After passing through the obstacles, the average uplink rate of n users to the relay node is for:

[0034]

[0035] Relay node throughput w D Equal to the sum of the uplink throughput and the downlink throughput:

[0036]

[0037] The average uplink and downlink rates of the macro base station are the same as the average downlink rate from the relay node to n users. The throughput of the macro base station is w B for:

[0038]

[0039] The relay node throughput evaluation index Z2 is defined as:

[0040]

[0041] According to the size of Z2, the relay node throughput level W2 is defined as:

[0042]

[0043] The relay node delay level W3 evaluation method in step 2 is:

[0044] The transmission delay of the D2D device is t s , the propagation delay without penetrating the obstacle is t c , the queuing delay is t l , processing delay t d , the propagation delay after penetrating obstacles will become larger to t c ′:

[0045]

[0046] Communication delay t D for:

[0047]

[0048] The average delay from macro base station to cellular users within the coverage area of ​​macro base station is The relay node delay evaluation index Z3 is defined as:

[0049]

[0050] According to the size of Z3, the relay node delay level W3 is defined as:

[0051]

[0052] The evaluation method of the relay node anti-interference level W4 in step 2 is:

[0053] Considering that the communication between the relay node and the macro base station is interfered by the cellular users, the distances from the jth cellular user to the relay node, the other m-1 cellular users and the base station are D cj , L cj and D Bj , the signal to interference and noise ratio SINR1 of the relay node is:

[0054]

[0055] Among them, σ 2 is the power of Gaussian white noise;

[0056] The signal-to-interference-to-noise ratio SINR2 of the jth cellular user is:

[0057]

[0058] The anti-interference index Z4 of the relay node is defined as:

[0059]

[0060] According to the size of Z4, the anti-interference level W4 of the relay node is defined as:

[0061]

[0062] Through the above-mentioned design scheme, the present invention can bring the following beneficial effects: a method for evaluating the performance level of relay-assisted D2D communication under emergency conditions, which takes into account the key indicators of coverage, throughput, latency, and anti-interference of relay nodes, and can evaluate the performance of relay nodes more comprehensively and finely, providing a scientific basis for the planning and optimization of emergency communication networks. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The present invention is further described below with reference to the accompanying drawings and specific embodiments:

[0064] Figure 1 The figure is a flow chart of a method for evaluating the performance level of relay-assisted D2D communication under emergency conditions. DETAILED DESCRIPTION

[0065] The present invention is further described below using the accompanying drawings and specific embodiments;

[0066] like Figure 1 As shown, a method for evaluating the performance level of relay-assisted D2D communication under emergency conditions includes a method for obtaining relay-assisted D2D communication data, a method for evaluating coverage level, a method for evaluating throughput level, a method for evaluating latency level, a method for evaluating anti-interference level, and a method for comprehensively scoring relay-assisted D2D communication performance. The specific contents are as follows:

[0067] (1) Relay-assisted D2D communication data acquisition method;

[0068] The data obtained through query and actual measurement include the coverage range R of the macro base station BS , the distance R from the macro base station to the relay node BD , the base station's transmission power is P B , assuming that there are n users with D2D devices in the emergency communication area, and the distance from the i-th user to the relay node is D i , i = 1, 2, ···, n, the relay node transmission power is P, there are m cellular users, and the distance from the jth cellular user to the relay node is D cj , j = 1, 2, ···, m, the average transmission power of m cellular users is The transmission and reception gain of the D2D device is G, and the channel gain of the communication within the coverage area of ​​the macro base station is G c , the path loss factor is α, and the wireless signal frequency f is 2400MHz, the loss factor of the kth layer obstacle material is a k The value can be between 0.463-0.464dB / cm. The communication mode between n users and the relay node is D2D communication. The uplink rate from the i-th user to the relay node is v ui , the average uplink rate from n users to the relay node is The downlink rate from the relay node to the i-th user is ν di , the average downlink rate from the relay node to n users is Channel utilization rate of relay node η D , the channel utilization rate of the macro base station η B , the transmission delay of the D2D device is t s , the propagation delay without penetrating the obstacle is t c , the queuing delay is t l , the processing delay is t d , the average delay from macro base station to cellular users within the coverage area of ​​macro base station is

[0069] (2) Coverage level assessment method;

[0070] The path loss from the user to the relay node PLOSS includes the propagation loss of the wireless signal in the air P free and the propagation loss of wireless signals through obstacles P ruin , which can be expressed as:

[0071] PLOSS=P free +P ruin (1)

[0073] Among them, the wireless signal propagation loss in the air is P free It can be expressed as:

[0074]

[0075] Where c is the speed of light and f is the frequency of the wireless signal;

[0076] The propagation loss of wireless signals penetrating obstacles P ruin for:

[0077]

[0078] Among them, a k Indicates the loss factor of the k-th obstacle material. The default loss factor is 0.464dB / cm and can be adjusted according to specific circumstances. kIndicates the thickness of the kth layer of obstacles. The default thickness is 26cm, which can be adjusted according to the specific situation. N is the total number of obstacles that penetrate;

[0079] Therefore, formula (1) can be expressed as:

[0080]

[0081] By default, the relay node is located at the edge of the macro base station, and the coverage radius R of the relay node can be expressed as:

[0082]

[0083] The relay node coverage evaluation index Z1 is defined as:

[0084]

[0085] According to the size of Z1, the coverage level W1 of the relay node is defined as:

[0086]

[0087] (3) Throughput level evaluation method;

[0088] The average uplink rate from n users to the relay node is Due to the influence of obstacles, the average uplink rate will be reduced. After passing through the obstacles, the average uplink rate of n users to the relay node is for:

[0089]

[0090] Relay node throughput w D It is equal to the sum of the uplink throughput and the downlink throughput, that is:

[0091]

[0092] By default, when the average uplink and downlink rates of the macro base station are the same as the average downlink rate from the relay node to n users, the throughput of the macro base station is w B for:

[0093]

[0094] The relay node throughput evaluation index Z2 is defined as:

[0095]

[0096] According to the size of Z2, the relay node throughput level W2 is defined as:

[0097]

[0098] (4) Delay level assessment method;

[0099] Communication delay includes transmission delay, propagation delay, queuing delay and processing delay. Transmission delay refers to the time required for a data packet to be sent from the user to the completion of transmission. Propagation delay depends on the propagation speed and transmission distance of the signal in the transmission medium. Queuing delay refers to the time a data packet waits for transmission in the network. Processing delay refers to the time required for a data packet to be processed in a network node.

[0100] Assume that the transmission delay of the D2D device is t s , the propagation delay without penetrating the obstacle is t c , the queuing delay is t l , processing delay t d , due to the propagation delay of penetrating obstacles, it will become larger to t c ′:

[0101]

[0102] Therefore, the communication delay t D for:

[0103] t D =t c ′+t l +t s +t d (14)

[0104] Considering that the average delay from macro base station to cellular users within the coverage area of ​​macro base station is The relay node delay evaluation index Z3 is defined as:

[0105]

[0106] According to the size of Z3, the relay node delay level W3 is defined as:

[0107]

[0108] (5) Anti-interference level evaluation method;

[0109] Since the relay node and cellular users communicate with the macro base station at the same time, the downlink resources of the relay node are reused with the uplink and downlink resources of ordinary cellular users. Therefore, the communication between the relay node and the macro base station is bound to be interfered by the cellular users. The distances from the jth cellular user to the relay node, the other m-1 cellular users and the base station are D cj , L cj and D Bj , the signal to interference and noise ratio SINR1 of the relay node is:

[0110]

[0111] Among them, σ 2 is the power of Gaussian white noise;

[0112] The signal-to-interference-to-noise ratio SINR2 of the jth cellular user is:

[0113]

[0114] The anti-interference index Z4 of the relay node is defined as:

[0115]

[0116] According to the size of Z4, the anti-interference level W4 of the relay node is defined as:

[0117]

[0118] (6) Comprehensive scoring method for relay-assisted D2D communication performance;

[0119] According to the relay node coverage level W1, relay node throughput level W2, relay node delay level W3, and relay node anti-interference level W4, calculate the relay node comprehensive score W:

[0120] W=λ1·W1+λ2·W2+λ3·W3+λ4·W4 (21)

[0121] Among them, λ1 is the weight of the relay node's coverage level, λ2 is the weight of the relay node's throughput level, λ3 is the weight of the relay node's delay level, and λ4 is the weight of the relay node's anti-interference level. Each weight can be adjusted according to the specific situation. The value range is (0,1), λ1+λ2+λ3+λ4=1, and the default is When 0.125≤W<0.25, the performance of the relay node is regarded as level three, when 0.25<W≤0.5, the performance of the relay node is regarded as level two, and when 0.5<W≤1, the performance of the relay node is regarded as level one.

[0122] The software program involved in the present invention is compiled based on mobile communication, network and computer processing technologies, which are technologies familiar to those skilled in the art.

[0123] The specific embodiments of the present invention are merely examples for clear explanation and are not limitations on the implementation methods. For ordinary technicians in the field, other different forms of changes or modifications can be made based on the above description. There is no need to list all the implementation methods here, and the obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for evaluating the performance level of relay-assisted D2D communication under emergency conditions, characterized by: The following steps are included: Step 1: Obtain relay-assisted D2D communication data, including the macro base station coverage R BS , the distance R from the macro base station to the relay node BD , the base station's transmission power is P B , assuming that there are n users with D2D devices in the emergency communication area, and the distance from the i-th user to the relay node is D i , i = 1, 2, ···, n, the relay node transmission power is P, there are m cellular users within the coverage of the macro base station, and the distance from the jth cellular user to the relay node is D cj , j = 1, 2, ···, m, the average transmission power of m cellular users is The transmission and reception gain of the D2D device is G, and the channel gain of the communication within the coverage area of ​​the macro base station is G c , the path loss factor is α, and the wireless signal frequency f is 2400MHz, the loss factor of the kth layer obstacle material is a k The value is 0.463-0.464dB / cm. The communication mode between n users and the relay node is D2D communication. The uplink rate from the i-th user to the relay node is v ui , the average uplink rate from n users to the relay node is The downlink rate from the relay node to the i-th user is ν di , the average downlink rate from the relay node to n users is Channel utilization rate of relay node η D , the channel utilization rate of the macro base station η B , the transmission delay of the D2D device is t s , the propagation delay without penetrating the obstacle is t c , the queuing delay is t l , the processing delay is t d , the average delay from macro base station to cellular users within the coverage area of ​​macro base station is Step 2: According to the relay node coverage radius and the distance from the macro base station to the relay node, establish the relay node coverage range evaluation index Z1, and define the relay node coverage range level W1 according to the size of Z1; according to the relay node throughput and the throughput of the macro base station, establish the relay node throughput evaluation index Z2, and define the relay node throughput level W2 according to the size of Z2; according to the communication delay and the average delay from the macro base station to the cellular users within the coverage range of the macro base station, establish the relay node delay evaluation index Z3, and define the relay node delay level W3 according to the size of Z3; according to the signal to noise ratio of the relay node and the signal to noise ratio of the jth cellular user, establish the relay node anti-interference evaluation index Z4, and define the relay node anti-interference level W4 according to the size of Z4; Step 3: Calculate the comprehensive score W of the relay node according to the coverage level W1, the throughput level W2, the delay level W3, and the anti-interference level W4 of the relay node in step 2: W=λ1·W1+λ2·W2+λ3·W3+λ4·W4 Among them, λ1 is the weight of the relay node’s coverage level, λ2 is the weight of the relay node’s throughput level, λ3 is the weight of the relay node’s delay level, and λ4 is the weight of the relay node’s anti-interference level. The value range is (0,1), λ1+λ2+λ3+λ4=1, and the default value is When 0.125≤W<0.25, the performance of the relay node is regarded as level three, when 0.25<W≤0.5, the performance of the relay node is regarded as level two, and when 0.5<W≤1, the performance of the relay node is regarded as level one.

2. According to the method for evaluating the performance level of relay-assisted D2D communication under emergency conditions in claim 1, it is characterized by: The coverage level W1 of the relay node in step 2 is defined as follows: The path loss from the user to the relay node PLOSS includes the propagation loss of the wireless signal in the air P free and the propagation loss of wireless signals through obstacles P ruin , expressed as: PLOSS=P free +P ruin Wireless signal propagation loss in the air free It is expressed as: In the formula, c is the speed of light, and f is the frequency of the wireless signal; The propagation loss of wireless signals penetrating obstacles P ruin for: In the formula, a k represents the loss factor of the k-th obstacle material, h k represents the thickness of the kth layer of obstacles, and N is the total number of penetrating obstacles; The path loss PLOSS from the user to the relay node is reformulated as: By default, the relay node is located at the edge of the macro base station, and the coverage radius R of the relay node is expressed as: The relay node coverage evaluation index Z1 is: According to the size of Z1, the coverage level W1 of the relay node is defined as:

3. The method for evaluating the performance level of relay-assisted D2D communication under emergency conditions according to claim 1 is characterized in that: The relay node throughput level W2 evaluation method described in step 2 is: The average uplink rate from n users to the relay node is Affected by obstacles, the average uplink rate is reduced. After passing through the obstacles, the average uplink rate of n users to the relay node is for: Relay node throughput w D Equal to the sum of the uplink throughput and the downlink throughput: The average uplink and downlink rates of the macro base station are the same as the average downlink rate from the relay node to n users. The throughput of the macro base station is w B for: The relay node throughput evaluation index Z2 is defined as: According to the size of Z2, the relay node throughput level W2 is defined as:

4. The method for evaluating the performance level of relay-assisted D2D communication under emergency conditions according to claim 1 is characterized in that: The relay node delay level W3 evaluation method in step 2 is: The transmission delay of the D2D device is t s , the propagation delay without penetrating the obstacle is t c , the queuing delay is t l , processing delay t d , the propagation delay after penetrating obstacles will become larger to t c ′: Communication delay t D for: t D =t c ′+t l +t s +t d The average delay from macro base station to cellular users within the coverage area of ​​macro base station is The relay node delay evaluation index Z3 is defined as: According to the size of Z3, the relay node delay level W3 is defined as:

5. The method for evaluating the performance level of relay-assisted D2D communication under emergency conditions according to claim 1 is characterized in that: The relay node anti-interference level W4 evaluation method described in step 2 is: Considering that the communication between the relay node and the macro base station is interfered by the cellular users, the distances from the jth cellular user to the relay node, the other m-1 cellular users and the base station are D cj , L cj and D Bj , the signal to interference and noise ratio SINR1 of the relay node is: Among them, σ 2 is the power of Gaussian white noise; The signal-to-interference-to-noise ratio SINR2 of the jth cellular user is: The anti-interference index Z4 of the relay node is defined as: According to the size of Z4, the anti-interference level W4 of the relay node is defined as:

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