Matlab Simulation and Source Code Implementation of Bit Error Rate of Spread Spectrum Despread Communication System
1. Introduction
Spread spectrum despreading technology is a communication method based on direct spread spectrum technology, which has high anti-interference and confidentiality, and can realize time division multiplexing in multi-user communication, so it is widely used in military communication and field of satellite communications. This article will introduce the Matlab simulation and source code implementation of the bit error rate of the spread spectrum despread communication system.
2. Spread spectrum despreading principle
Spread spectrum despreading technology refers to spreading the signal to be sent by using a pseudo-random code at the sending end, and at the same time, using the same pseudo-random code to despread the received signal at the receiving end to restore the original signal. Among them, spread spectrum refers to using a high-speed code sequence to modulate the original signal into a broadband signal, and despreading refers to using the same high-speed code sequence at the receiving end as the sending end to restore the received broadband signal to the original signal.
Spread spectrum technology can convert a signal with a narrower bandwidth into a signal with a wider bandwidth to improve the anti-interference ability of the signal. The despreading technology can restore the transmitted broadband signal to the original signal, thereby improving the security of information transmission while ensuring the quality of information transmission.
3. System simulation and source code implementation
In Matlab, we can simulate the spread spectrum despread communication system to obtain performance indicators such as the bit error rate of the system. Here is the source code used in this article:
%定义初始参数
SNR_dB = 0:2:10;%信噪比范围
SNR = 10.^(SNR_dB/10);%将SNR转化为线性值
BER=zeros(length(SNR),1);
N=100000;%仿真发送的比特数量
n=64;%码元长度
m=4;%M序列的阶数
G=[1 1 1;1 0 1];%生成矩阵
p=[0 1 1];%初态
s=[1 0 0];%输入序列
%生成M序列
P=p;
for i=1:n*m-1
P(i+3)=mod(sum(G(:,1).*P(i:i+2)),2); %M序列
end
code=P(1:n);
%发送端
for k=1:length(SNR)
snr = SNR