M元扩频信号的一种差分检测方法

提出了一种M元扩频信号的差分检测方法,发端将输入的串行数据转换为并行数据,然后进行M元差分编码、M元扩频编码和载波调制。为了降低了组合相关干扰和选码的难度,发端使用了修正的循环扩频码进行M元扩频。这种扩频码是在原型扩频码的基础上分别添加循环前缀和循环后缀后得到的。接收端利用一个SAWTDL器件对接收信号进行相关检测,根据M元扩频码的编码规则,SAWTDL器件输出的自相关峰之间的间隔包含了发送的数据信息,接收机通过对相邻自相关峰出现的时间间隔进行差分译码,即可恢复出数据信息。该方法只需要一个SAWTDL器件就可实现对M元扩频信号的相关检测,简化了接收机的结构。论文对系统的误码性能和数据传输能力进行了分析,仿真结果与理论分析的结论一致。

A Differential Detection Method for M-ary Spread Spectrum Signal

A differential detection method is proposed for M-ary spread spectrum signal process.The serial input data is converted into parallel data before M-ary differential encoding,M-ary spread spectrum modulation and carrier modulation.The influence of combination-correlation interference and the selection difficulty of M-ary spreading codes can be decreased by employing the presented Modified Cyclic Spreading Codes(MCSC).The MCSC is composed of three parts: cyclic prefix,the prototype spreading code and its cyclic postfix.The proposed receiver can achieve M-ary de-spread spectrum with only one chip SAWTDL device,which reduces the complexity of receiver effectively.Based on the coding rule,the interval between neighboring autocorrelation peaks loads the transmitted information which can be restored by M-ary differential decoding.The BER performances and data transmission capability of the system are analyzed.The conclusion drawn from computer simulation is identical with the theoretical analysis.