写一段OFDM插入导频的matlab代码

以下是OFDM插入导频的MATLAB代码：

% OFDM插入导频
clc;
clear all;
close all;

% 参数设置
N = 64; % 子载波数
cp_len = 16; % 循环前缀长度
data_len = N - cp_len; % 数据长度
num_ofdm_symbols = 10; % OFDM符号数
pilot_spacing = 4; % 导频间隔
pilot_seq = [1 1 -1 1]; % 导频序列

% 生成随机数据
data = randi([ 1], data_len*num_ofdm_symbols, 1);

% 将数据分成OFDM符号
data_ofdm = reshape(data, data_len, num_ofdm_symbols);

% 生成导频序列
pilot = zeros(N, num_ofdm_symbols);
for i = 1:num_ofdm_symbols
pilot_idx = 1:pilot_spacing:N;
pilot(pilot_idx, i) = pilot_seq.';
end

% 将数据和导频合并
ofdm_symbols = zeros(N, num_ofdm_symbols);
ofdm_symbols(1+cp_len:end, :) = data_ofdm;
ofdm_symbols(pilot_idx, :) = pilot(pilot_idx, :);

% IFFT变换
ofdm_time = ifft(ofdm_symbols, N);

% 添加循环前缀
ofdm_cp = [ofdm_time(end-cp_len+1:end, :); ofdm_time];

% 绘制OFDM符号
figure;
plot(real(ofdm_cp(:, 1)));
title('OFDM符号');

% 信道传输
ofdm_rx = ofdm_cp;

% 移除循环前缀
ofdm_rx = ofdm_rx(cp_len+1:end, :);

% FFT变换
ofdm_rx_fft = fft(ofdm_rx, N);

% 提取导频
pilot_rx = ofdm_rx_fft(pilot_idx, :);

% 估计信道
h_est = pilot_rx./pilot;

% 去除导频
ofdm_rx_fft(pilot_idx, :) = [];

% 解调数据
data_rx = reshape(ofdm_rx_fft, data_len*num_ofdm_symbols, 1);

% 比特错误率
ber = sum(xor(data, data_rx))/length(data);
fprintf('比特错误率: %f\n', ber);