说明：  此函数用于IS-95前向链路系统的仿真，包括扩频调制，匹配滤波，RAKE接收等相关通信模块。仿真环境: 加性高斯白噪声信道.
(This function is used to forward link IS-95 system simulation, including the spread spectrum modulation, matched filter, RAKE receiver, and other related communication module. Simulation environment: additive white Gaussian noise channel.)