说明：  实现了一个直接扩频系统，使用BPSK作为调制解调方法。并比较白噪声AWGN及瑞利衰落(rayleigh fading)环境下，误码率的影响。
(There are two files in the zip folder. bpsk_spread.m and jakesmodel.m Steps for simulation: 1] Run jakesmodel.m first 2] Then run bpsk_spread.m . 3] Note that during the first run bpsk_spread.m has no rayleigh fading.This is because the corresponding code has been commented 4] The resulting performance is stored in BER_awgn. 5] Now uncomment the Rayleigh Fading code in bpsk_spread.m file. 6] Same time comment BER_awgn (line 112) and uncomment BER_ray variable. 7] Run the simulation. To compare the perfromances of the receiver using DSSS plot the BER_awgn and BER_ray >>semilogy([1:8],BER_awgn(1:8), g* ) hold on semilogy([1:8],BER_ray(1:8), -.b* ) hold on grid on )