Research for applying M-ary amplitude and phase shift keying modulation to mobile communications

考虑到接收信号之间的自相关性，将多符号差分检测（MSDD）应用于任意幅度和相移键控调制。该检测方案对16APSK和32APSK的SER性能优于以往文献中的常规方法。为了降低接收端的计算复杂度和计算量，提出了一种快速计算方法，并将其应用于该检测方案中使用m算法的树路径搜索。结果表明，在一种实用的接收机结构下，接收到的待估计信号的序列长度可以选择相当大的范围，并且在较快的衰落信道中，也不会出现误差底，且具有最佳环比的理想相干检测性能。最后，我们提出了使用多符号差分检测度量的串行级联编码M-ary差分幅度和相移键控（MDAPSK）的迭代解码。在发射机中，在涡轮编码器中使用串行串联卷积码，编码器的输出用差分星正交调幅调制。在接收端，turbo译码器对软输出MSDD （SO-MSDD）进行迭代译码。为了在turbo编码器和解码器中使用随机交织器，我们近似了MSDD的决策度量。此外，为了使符号之间的可靠性相等，这里使用滑动MSDD。考虑接收序列的自相关性，采用快速计算算法（FCA）得到MSDD的决策度量。计算机仿真结果表明，在瑞利衰落信道中，随着观测序列长度的增大，该系统的误码率性能更接近于无差分编码的理想相干检测。

Multiple-symbol differential detection (MSDD) considering the auto-correlation among the received signals is applied to M-ary amplitude and phase shift keying modulation. The SER performances of 16APSK and 32APSK with this detection scheme show better than that of the conventional methods in the past literature. To reduce the complexity and the computational efforts in the receiver, a fast calculation method is proposed and it is applied to tree path search using M-algorithm in this detection scheme. As the result, the sequence length of received signals to be estimated can be chosen quite large under a practicable receiver structure, and we confirm that the SER performance shows almost the same as that of the ideal coherent detection with the optimum ring ratio and error floor is not appeared even for relatively fast fading channels.Lastly, we propose iterative decoding for serial concatenation coded M-ary differential amplitude and phase shift keying (MDAPSK) using multiple-symbol differential detection metric. In the transmitter, serial concatenated convolutinal code is used in a turbo encoder, and the output of the encoder is modulated with the differential star quadrature amplitude modulation. In the receiver, the turbo decoder takes iterative decoding to the output of Soft Output MSDD (SO-MSDD). To use random-interleaver in turbo encoder and decoder, we approximate the decision metric of the MSDD. Moreover, to make reliability among symbols equal, sliding MSDD is used here. And the fast calculation algorithm (FCA) is used to get the decision metric of the MSDD considering the autocorrelation of a received sequence. Through computer simulations, it is confirmed that the bit error rate performance of this system is closer to that of the ideal coherent detection without differential encoding as the length of an observed sequence becomes larger over Rayleieh fading channels.