單載波 IEEE 802.15.3c 系統之基頻訊號處理與資料偵測技術

Abstract

近幾年來，室內個人無線網路通訊的趨勢走向於由高傳輸率所支援的高解析度視訊串流傳輸，而IEEE 802.15.3c 標準即是為了因應此類需求而制定的，其操作於60GHz免認證頻帶，並提供1.5 Gbps以上的傳輸速率。本論文針對此標準之單一載波模式的封包格式與60GHz下的通道環境特性，進一步設計其基頻接收機架構，其中包含符元時間估測、通道估測、以及資料偵測等部份。在符元時間估測部分，本文針對60GHz頻帶下特殊的通道分散特性，提出利用前置訊息中CES (cahnnel estimation sequence)部份與Golay code的相關運算做為偵測第一根響應的依據，以避免估測出錯誤的符元時間；而對於通道估測部分，本文提出利用不同CES的排列方式取得兩組估測通道並平均用以減輕雜訊對於估測準度上的影響，經過運算得知此方法可降低四分之一的雜訊能量；最後本文利用球面解碼演算法的概念提出一適用於單一載波系統的資料偵測方法，來降低系統因多重通道而產生的ISI效應，其解碼矩陣分割方式可以避免傳統球面解碼中QR分解的使用亦可利用球面解碼方式逐層將資料偵測出來，此資料偵測方法可適用於任何SCBT系統，並可得到較傳統MMSE頻域等化器高的BER效能表現。

In recent years, the trend of wireless personal network is to have higher and higher data rate to facilitate the high definition video stream transmission. The IEEE 802.15.3c standard was defined to support this kind of demands. It operates at the 60 GHz unlicensed band and provides high data rates of more than 1.5 Gbps. The baseband receiver structure has been designed in this thesis according to the frame format and the characteristics of the channel environment at 60GHz. Some effective methods for symbol timing estimation and channel estimation were proposed. For symbol timing detection, the special channel dispersion at 60GHz is focused in this thesis. A method to detect the first tap of channel impulse response within the region of the correlation between Golay code and CES (channel estimation sequence) part of preamble is also discussed. For the channel estimation, the method adopting the average of two estimated channel by differently arranged CES can suppress the noise effect upon the accuracy to estimate the channel. After computation, the noise power can be reduced by a quarter. Furthermore, a data detection algorithm for single carrier block transmission system was brought up, which utilizes the concept of sphere decoding to relieve the ISI effect. Its particular method to transform the original mathematical ISI equation can avoid the complicated QR decomposition and perform data detection by using the state-of-the-art sphere decoding technique. This method can be applied to any SCBT system and get better BER performance as compared with the traditional frequency-domain MMSE equalizer.