差分空时编码系统中的多共道用户应用

通过分析和推导，指出在多用户差分空时分组编码系统中，发射端的多个共道用户采用同步编码和同步分组传输时，接收端无法在未知信道状态信息的情况下进行差分解码的结论．为了能够保持原有编码的差分解码的特性，提出了一种新型的多用户交错结构，利用多个共道用户所发射的数据在时间上的不同时延彼此交错，形成传输的非同步．此时的接收端可通过辗转迭代计算获得等效的无共道干扰传输结果，并通过差分计算进行解码处理．具有这种交错结构的系统能够在信道未知的情况下支持多个用户的同时传输，并且在接收端能够实现正确的解码工作．

The differential space-time block coding system with multiple co-channel users

After discussing the multi-user differential space-time block coding system, and analyzing the realizability of differential decoding method, we can draw the conclusion that the receiver can not decode the information of various users while the channel is unknown if multiple co-channel users in the system are synchronous. To solve this problem, a new kind of offset system structure is presented. The multiple co-channel users transmit signals nonsynchronously with different offset delays, and the receiver can iteratively subtract to get the equivalent nil-interference result, which can be disposed of with the differential method. While the multi-user system is constructed accordint to the new offset structure, the receiver can easily cancel the interference and decode the signal even if the channel state information is unknown.