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

将多符号差分检测(MSDD)技术应用于多进制幅度相移键控调制中，考虑了接收信号之间的自相关性。采用该检测方案的16APSK和32APSK的误码率性能优于以往文献中常用的检测方法。为了降低接收端的复杂度和计算量，提出了一种快速计算方法，并将其应用于基于M算法的树路径搜索中。结果表明，在一种实用的接收机结构下，可以选择较大的接收信号序列长度进行估计，并且在环比最优的情况下，其误码率性能与理想相干检测几乎相同，即使在相对较快的衰落信道中也不会出现误码平台。最后，提出了基于多符号差分检测度量的串行级联编码多进制差分幅相键控(MDAPSK)的迭代译码方案。在发射机中，Turbo编码器采用串行级联卷积码，编码器的输出采用差分星正交幅度调制。在接收端，Turbo译码对软输出MSDD(SO-MSDD)的输出进行迭代译码。为了在Turbo编解码器中使用随机交织器，我们对MSDD的判决度量进行了近似。此外，为了使符号之间的可靠性相等，这里使用了滑动MSDD。考虑到接收序列的自相关性，利用快速计算算法(FCA)得到MSDD的判决度量。通过计算机仿真，证实了在瑞利衰落信道下，随着观测序列长度的增大，该系统的误码率性能更接近无差分编码的理想相干检测系统。

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.