摘要
本文首先介绍了连续相位调制CPM (ContinuousPhaseModulation)的分解模型[1] ,得到CPM调制可以分解为一个线性连续相位编码CPE (ContinuousPhaseEncoder)和无记忆调制的组合 ;接着基于CPM的错误事件和递归特性 ,推出了采用CPM扩频调制的TurboCDMA系统模型 ,这里CPM扩频调制作为递归内码 ,与外编码器及交织器级连构成Turbo迭代系统 ,该系统有明显的交织增益 .利用系统的迭代解调解扩和解码的特点 ,设计了软输入输出的接收机 ,接收机中解调器采用MAP(MaximumAPosterior)和SOVA(SoftOutputViterbiAlgorithm)算法 ,解码器采用MAP算法 .仿真结果表明CPM调制器作为内码形成级连迭代系统交织增益非常明显 .
This paper firstly proposes a decomposed model of CPM modulator which consists of a linear CPE and a memoryless modulator.Based on the error event analysis and recursive feature of CPM signal,a Turbo CDMA system with CPM spreading modulation is proposed,in which CPM modulator as a recursive inner coder can be used to concatenate with other outer coders and interleaver into a Turbo iterative system to improve the performance of CDMA system.With the use of iterative demodulation,despreading and decoding an iterative soft-input-soft-output (SISO) receiver is proposed in this paper,in which MAP and SOVA algorithms are implemented in the demodulator,respectively,and MAP algorithm is realized in the decoder.Simulations have shown CPM spreading modulator as an inner coding modulator can provide the interleaver gain explicitly.
出处
《电子学报》
EI
CAS
CSCD
北大核心
2002年第10期1466-1469,共4页
Acta Electronica Sinica
基金
香港城市大学项目基金 (No CityU 1 1 1 5/97E)
