再生量子化中継伝送における量子化しきい値の最適化に関する一検討

This paper investigates optimizations of threshold values involved in quantization of log likelihood ratio (LLR), which is derived at relay node in decode-quantize-and-forward (DQF) relaying. In order to carry out exact decoding for LLR compress encoder of DQF relaying, we explicitly define an equivalent LLR transfer signal model. Under the definition, we propose an efficient approximation, which drastically reduces computational efforts for decoding. After carefully inspecting impacts of the quantization threshold, decode-adaptive quantize-and-forward (DAQF) that adaptively selects optimal threshold according to channel states is proposed. Finally, we validate the proposed system by computer simulations.