使用csma/ca生成一个基于优先级的在不同节点数量下的平均能耗MATLAB代码
时间: 2023-12-03 20:47:13 浏览: 37
以下是一个基于优先级的CSMA/CA协议的MATLAB代码,能够计算在不同节点数量下的平均能耗。需要注意的是,此代码仅供参考,具体实现可能因应用场景的不同而有所调整。
```
% CSMA/CA protocol with priority-based approach
% Calculates average energy consumption for varying number of nodes
% Assumes random backoff and binary exponential backoff for contention
% Assumes fixed packet size and transmission range
% Assumes simple energy model where energy is proportional to transmission distance
clear all;
close all;
% Simulation parameters
numNodes = 10:10:100; % Varying number of nodes
txRange = 100; % Transmission range (m)
packetSize = 1000; % Packet size (bits)
dataRate = 1e6; % Data rate (bps)
slotTime = 50e-6; % Slot time (s)
sensingTime = 5e-6; % Sensing time (s)
CWmin = 16; % Minimum contention window size
CWmax = 1024; % Maximum contention window size
backoffMethod = 'binary exponential'; % Contention resolution method
priorityScheme = 'random'; % Priority scheme (random or fixed)
% Energy model parameters
E_elec = 50e-9; % Energy required to transmit/receive a bit (J/bit)
E_amp = 100e-12; % Energy required to amplify a signal (J/m^2)
% Loop over number of nodes
for n = 1:length(numNodes)
N = numNodes(n);
% Initialize simulation variables
t = 0; % Current time (s)
totalEnergy = 0; % Total energy consumed (J)
numPackets = 0; % Number of packets transmitted
numCollisions = 0; % Number of collisions
% Randomly distribute nodes within transmission range
nodes = rand(N,2)*txRange;
% Main simulation loop
while t < 1 % Simulation time (s)
% Check if any node has a packet to transmit
for i = 1:N
if rand < dataRate*packetSize*slotTime && nodes(i,3) == 0 % Node has a packet to transmit and is not currently transmitting
% Determine priority level
if strcmp(priorityScheme,'random')
priority = randi([1 10]); % Random priority level between 1 and 10
else
priority = mod(i,10) + 1; % Fixed priority level based on node index
end
% Calculate backoff time
if strcmp(backoffMethod,'random')
CW = CWmin + floor(rand*(CWmax-CWmin+1)); % Random backoff
else
CW = 2^mod(priority-1,5)*CWmin; % Binary exponential backoff
end
nodes(i,3) = CW*slotTime; % Set backoff timer for node
end
end
% Check if any node has finished transmitting
for i = 1:N
if nodes(i,3) == 0 && nodes(i,4) > 0 % Node has finished transmitting
nodes(i,4) = 0; % Reset transmission timer for node
end
end
% Check for collisions
for i = 1:N
if nodes(i,4) > 0 % Node is currently transmitting
for j = 1:N
if i ~= j && nodes(j,4) > 0 % Other node is also transmitting
if sqrt((nodes(i,1)-nodes(j,1))^2 + (nodes(i,2)-nodes(j,2))^2) <= txRange % Transmission overlap
nodes(i,4) = 0; % Abort transmission for node i
nodes(i,3) = 0; % Reset backoff timer for node i
numCollisions = numCollisions + 1; % Increment collision counter
break;
end
end
end
end
end
% Transmit packets
for i = 1:N
if nodes(i,3) == 0 && nodes(i,4) == 0 % Node is ready to transmit
for j = 1:N
if i ~= j % Other node in network
if sqrt((nodes(i,1)-nodes(j,1))^2 + (nodes(i,2)-nodes(j,2))^2) <= txRange % Transmission possible
% Determine priority level
if strcmp(priorityScheme,'random')
priority = randi([1 10]); % Random priority level between 1 and 10
else
priority = mod(i,10) + 1; % Fixed priority level based on node index
end
% Calculate energy consumption
distance = sqrt((nodes(i,1)-nodes(j,1))^2 + (nodes(i,2)-nodes(j,2))^2);
energy = E_elec*packetSize + E_amp*distance^2*packetSize;
totalEnergy = totalEnergy + energy;
numPackets = numPackets + 1;
% Set transmission timer for node i
nodes(i,4) = packetSize/dataRate;
% Break out of loop to avoid multiple transmissions
break;
end
end
end
end
end
% Update backoff timers
for i = 1:N
if nodes(i,3) > 0 % Node is currently backoff
nodes(i,3) = nodes(i,3) - slotTime; % Decrement backoff timer
end
end
% Update transmission timers
for i = 1:N
if nodes(i,4) > 0 % Node is currently transmitting
nodes(i,4) = nodes(i,4) - slotTime; % Decrement transmission timer
end
end
% Increment simulation time
t = t + slotTime;
end
% Calculate average energy consumption per packet
avgEnergyPerPacket(n) = totalEnergy/numPackets;
% Calculate packet loss rate
packetLossRate(n) = numCollisions/numPackets;
end
% Plot results
figure;
subplot(2,1,1);
plot(numNodes,avgEnergyPerPacket,'-o');
xlabel('Number of nodes');
ylabel('Average energy consumption per packet (J)');
title(sprintf('CSMA/CA with priority-based approach (method = %s)',backoffMethod));
subplot(2,1,2);
plot(numNodes,packetLossRate,'-o');
xlabel('Number of nodes');
ylabel('Packet loss rate');
```