RS-CC串接碼應用於無線通訊之效能分析

Performance analysis of RS-CC concatenated code in wireless communication

梁書潤(Shu-Jun Liang)

指導教授 ： 劉玉蓀

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00583

摘要

近年來RS-CC(Reed Solomon – Convolution Codes)串接碼(Concatenated code)被廣泛應用於無線通訊技術上，像是WiMAX 802.16d與DVB-T的規格均採用RS-CC串接碼與OFDM(Orthogonal Frequency-Division Multiple ; OFDM)調變技術。WiMAX的RS(Reed Solomon ; RS)碼支援縮短(shorten)與打洞(puncture)機制，解碼器則採用解錯誤與抹失(error and erasure)的功能，此系統共支援六種不同碼率的RS碼，RS碼更正能力有2、4、6與8個位元組四種。而DVB-T僅支援縮短機制，所以解碼器僅需要採用解錯誤(error-only)功能即可，此系統的RS編碼碼率固定為188/204，更正能力為8個位元組。論文中軟體實現的RS解碼器演算法同時支援WiMAX與DVB-T所要求的功能。而兩種系統的摺積解碼器皆採用硬式決策(Hard decision)維特比(Viterbi)演算法。本論文以WiMAX與DVB-T通道編碼系統加上AWGN與Rayleigh衰減通道，呈現其抗雜訊的效能。由於DVB-T系統必須判斷經過RS解碼後的封包是否為正確的封包，因此在本論文最後針對RS解碼器提出五種判斷封包解碼錯誤方式，以提供上層解讀封包的參考依據。

關鍵字

RS-CC串接碼 ； RS碼 ； 硬式決策 ； 維特比演算法

並列摘要

RS-CC concatenated codes has been widely used in many wireless communication technologies recently, such as WiMAX 802.16d and DVB-T standard. Both of them adopt RS-CC and OFDM technology as their channel coding and modulation. In WiMAX system, RS codes supports shorten and puncture function, so that decoder needs the ability to decode error and erasure. The RS codes for WiMAX system supports 6 different code rates, and it has 4 kind of correcting ability 2, 4, 6 and 8, respectively. However DVB-T only supports shorten function, so that decoder only needs the ability to decode error. The codes rate of RS codes in DVB-T system is fixed at 188/204, and it can correct 8 byte per pocket. In this paper, our RS decoder can achieve WiMAX and DVB-T system requiem. Convolutional decoder for WiMAX and DVB-T system both adopt hard-deccision viterbi algorithm. We present the performance of WiMAX and DVB-T channel coding system in AWGN and Rayleigh fading channel. Due to DVB-T PHY Layer has to judge whether the decoded packet is correct or not, therefore we proposed 5 error detection criterions in chapter 4, so that the upper Layer can use this message as their decoding reference.

並列關鍵字

RS-CC concatenated ； Reed-Solomen codes ； hard-decision ； Viterbi algorithm

參考文獻

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