生成一个基于优先级的csma/ca不同节点数量下平均时延的MATLAB代码

以下是一个基于优先级的CSMA/CA不同节点数量下平均时延的MATLAB代码：

clear;
clc;

% 设置仿真参数
numNodes = 10:10:100; %不同节点数量
numSimulations = 100; % 每种节点数量的仿真次数
cwMin = 15; % 最小竞争窗口大小
cwMax = 1023; % 最大竞争窗口大小
slotTime = 9e-6; % 描述单个时隙的时间
sifsTime = 16e-6; % 短间隙时间
preambleTime = 144e-6; % 预备时间
ackTime = 16e-6; % 应答时间
payloadSize = 1500 * 8; % 数据包大小
bitRate = 54e6; % 无线电信号传输速率
headerSize = 28 * 8; % 数据包头大小
dataRate = bitRate / (headerSize + payloadSize); % 数据传输速率
packetTime = (headerSize + payloadSize) / dataRate; % 数据包传输时间
numRetransmissions = 7; % 最大重传次数

% 初始化结果存储矩阵
averageDelay = zeros(length(numNodes), 1);
simulations = zeros(length(numNodes), 1);

% 仿真开始
for i = 1:length(numNodes)
    for j = 1:numSimulations
        % 初始化节点
        nodes = struct([]);
        for k = 1:numNodes(i)
            nodes(k).backoffCounter = randi([0 cwMin-1]);
            nodes(k).cw = cwMin;
            nodes(k).packet = struct([]);
            nodes(k).collision = 0;
            nodes(k).success = 0;
            nodes(k).delay = 0;
        end
        
        % 模拟单次传输
        while true
            % 寻找有数据包的节点
            nodesWithPackets = find(arrayfun(@(x) ~isempty(x.packet), nodes));
            if isempty(nodesWithPackets)
                break;
            end
            
            % 筛选出优先级最高的节点
            priorityNodes = nodes(nodesWithPackets);
            priorityNodes = priorityNodes([priorityNodes.packet]);
            if length(priorityNodes) > 1
                [~, idx] = max([priorityNodes.priority]);
                priorityNodes = priorityNodes(idx);
            end
            
            % 执行竞争
            for k = 1:numNodes(i)
                if ~isempty(nodes(k).packet)
                    continue;
                end
                
                if nodes(k).backoffCounter == 0
                    nodes(k).packet = struct('priority', randi([0 3]), 'retransmissions', 0);
                    nodes(k).packetArrivalTime = j * packetTime;
                else
                    nodes(k).backoffCounter = nodes(k).backoffCounter - 1;
                end
            end
            
            % 检测碰撞
            if sum([nodes.packet]) > 1
                for k = 1:numNodes(i)
                    if isempty(nodes(k).packet)
                        continue;
                    end
                    
                    if nodes(k).collision == 0 && nodes(k).success == 0
                        nodes(k).cw = min(2*nodes(k).cw, cwMax);
                        nodes(k).backoffCounter = randi([0 nodes(k).cw-1]);
                    end
                    nodes(k).collision = 1;
                    nodes(k).packet = [];
                end
            else
                % 筛选出发送成功的节点
                successfulNode = nodes([nodes.packet].success == 1);
                if length(successfulNode) > 1
                    [~, idx] = max([successfulNode.priority]);
                    successfulNode = successfulNode(idx);
                end
                
                % 更新延迟和成功标志
                for k = 1:numNodes(i)
                    if isempty(nodes(k).packet)
                        continue;
                    end
                    
                    if nodes(k).packet == successfulNode.packet
                        nodes(k).delay = j * packetTime - nodes(k).packetArrivalTime;
                        nodes(k).success = 1;
                    end
                    
                    nodes(k).packet = [];
                end
                
                % 重置节点参数
                for k = 1:numNodes(i)
                    if nodes(k).collision == 1
                        nodes(k).backoffCounter = randi([0 nodes(k).cw-1]);
                        nodes(k).collision = 0;
                    elseif nodes(k).success == 1
                        nodes(k).backoffCounter = randi([0 cwMin-1]);
                        nodes(k).cw = cwMin;
                        nodes(k).success = 0;
                    else
                        nodes(k).backoffCounter = nodes(k).backoffCounter - 1;
                    end
                end
            end
        end
        
        % 计算平均延迟
        successfulNodes = nodes([nodes.success]==1);
        if ~isempty(successfulNodes)
            simulations(i) = simulations(i) + 1;
            averageDelay(i) = averageDelay(i) + mean([successfulNodes.delay]);
        end
    end
end

% 绘制结果图表
averageDelay = averageDelay ./ simulations;
plot(numNodes, averageDelay);
xlabel('Number of nodes');
ylabel('Average delay (s)');
title('Priority-based CSMA/CA Performance');