腓特比解碼器可適性路徑消去法

An Adaptive Implementation Of Trace Delete Method In Viterbi Decoders

高啟超(Chi-Chao Kao)

指導教授 ： 馬尚智

中原大學/工學院/電機工程研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500195

摘要

我們一般所知道的存活路徑(survivor path)儲存單元記憶體管理技術有三種，分別是記錄交換方式(register-exchange method----REM)、回溯追蹤方法(trace-back method----TBM)和路徑消去法（trace-delete method）。記錄交換方式是簡單的概念但不適當於超大積體電路‚因為須要要求很大的電力消耗及空間大的晶片位置。在超大積體電路中‚回溯追蹤方法是比較好的方法。尤其是用腓特比解碼 (viterbi decoding ----VD)‚比較會有大的約束長度和高的效能。為了達到高速功能‚回溯追蹤方法的暫存器是採用後進先出(LIFO)和必須使用多工讀取功能。這個多工的結果是建立在複雜的控制邏輯。第三種是路徑消去法。找到一些狀態並沒有與下一個狀態相連接，並且將進入這些狀態的路徑完全刪除，最後只有一個狀態存活。本論文要探討的是腓特比解碼器可適性路徑消去法，只要檢查到存活狀態只有一個的時候，馬上進行解碼動作，提升達成效率

關鍵字

回溯追溯法 ； 腓特比 ； 路徑消去法 ； 迴旋碼

並列摘要

The well known method for survivor path storage and decoding are the register-exchange method（REM）、the trace-back method（TBM）and the trace-delete method .The REM is conceptually simple，but it is not appropriate for VLSI implementation because it requires large power consumption and large chip area

The TBM is the preferred method in the VLSI implementation of Viterbi decoders（VD）having large constraint length and high performance. However‚the TBM requires last-in-first-out(LIFO) buffer and has to use multiple read operation for high speed operation. This multiple operation result in complex control logic. The third method is trace-delete method，only one state is survived at last stage and find the states that has no connection with the next states and deletes recursively the paths coming into these states. We proposed method － an adaptive implementation of trace deletion method in Viterbi decoders.An adaptive number of recursion can be achieved if the state existence signals are checked.

並列關鍵字

VITERBI ； TBM ； TDM

參考文獻

[1] Suk-Jin, Myeong Hwan Lee and Hyung-Jin Choi, “A New Surivor Memory Management Method In Viterbi Decoders : Trace-Delete Method and Its Implementation.”1996 IEEE

[2] Grand. Alliance HDTV System Specification,submitted to the ACATS technical subgroup, Fen.1994.

[3] Shang-Chih Ma, and Yao-Liang Chung, ”A Reduced-Complexity Implementaion of Trace Delete Method ”IEEE. Trans. Inform. ,Aug. 2004

[4] Suk-Jin, Myeong Hwan Lee and Hyung-Jin Choi, “A New Surivor Memory Management Method In Viterbi Decoders .”1996 IEEE

[5] ATSC Digital Television Standard, Advanced Television Systems Committee,Sept. 1995.