適用於巨量天線系統之整合訊息傳遞偵測與極化碼解碼接收機

Abstract

本論文為一個面積1.34mm2 透過40nm 製程實作，針對四位元相位偏移調變(QPSK)之巨量天線系統軟式輸出訊息傳遞偵測器(Message passing detector, MPD) 與極化碼(Polar code) 解碼器進行設計。本研究提出的可靠符元干擾消除技術以及適應性變異數偵測降低了訊息傳遞偵測器百分之九十以上的複雜度，並提供軟式資訊輸出給錯誤更正碼(Error correction code, ECC) 解碼器使用。透過記憶體摺疊(Memory Folding) 節省將近一半的記憶體使用量。交錯式雙向傳遞雙級解碼架構也被提出來減少極化碼解碼流程的延遲時間。這個作品展示了第一顆整合訊息傳遞偵測器與極化解碼器的實作，在巨量天線系統情境下最高可以達到每秒7.61Gb 的吞吐量。為了達到通道容量最大化效果，必須的軟式輸出訊息傳遞偵測器也被提出。和過去的作品進行比較，在同樣的天線陣列下，本作品在提供軟式輸出的同時仍可以達到6.9 倍高的吞吐量。設計提出的雙向極化碼解碼器在相同的能量輸入下可以達到1.35 倍的輸出量。

A 1.34mm2 40nm CMOS soft-output message-passing detector and bidirectional polar decoder are designed for a QPSK massive MIMO system. The proposed reliable symbol interference cancellation technique and adaptive variance detection reduce the complexity of message passing detector (MPD) by more than 90% and generate soft log likelihood ratio (LLR) information for an ECC decoder. Exploiting a folded memory configuration saves half memory elements. An interleaved bidirectional propagation double column polar decoder is proposed to reduce the total latency of the whole decoding procedure. This work presents the first integration of an MPD and a polar decoder, delivering a throughput of 7.61Gb/s for massive MIMO systems. A soft-output MPD, which is essential to maximize channel capacity, is proposed. Compared to previous solutions, the proposed MPD achieves a 6.9 higher throughput with 49% less energy, despite the soft outputs. The proposed bidirectional polar decoder achieves a 1.35 increase in throughput with comparable energy inputs.