結合相差編碼與籬柵編碼調變的碼搜尋

Code Searches for Trellis-Coded Modulation with Differential Encoding

呂柏宣(Bo-Shuan Lu)

指導教授 ： 魏瑞益

國立中央大學/資訊電機學院/通訊工程學系/碩士(2015年)

摘要

相差編碼是一個在傳送端的傳統技術，其可在接收端有簡單的非同調檢測器。另一方面，籬柵編碼調變是一種提供可靠數據傳輸的頻寬效益技術。在本論文中，我們在通道相位同調N為2個符號的情況下考慮籬柵編碼調變加相差編碼。此外，在多位元相位偏移調變訊號下，我們提出一種由相差編碼擴展的新籬柵編碼調變，稱為相差籬柵編碼調變。相差籬柵編碼調變是一種籬柵編碼調變加相差編碼，其籬柵圖上的狀態被定義在不同的狀態下會有不同的相差編碼。最後，我們提出一種相差編碼設計方式來完成非同調非災難性的相差籬柵編碼調變。

對於籬柵編碼調變加相差編碼以及相差籬柵編碼調變兩者，我們提出增加距離量和使用集合分割。此外，本論文將會分析集合分割、設計或搜尋到的籬柵碼以及它們的最小距離。在碼率為每一符號為2位元的情況下，我們皆找到對於籬柵編碼調變加相差編碼以及相差籬柵編碼調變兩者，比原始碼更好的新碼，其也具有較好的錯誤率。另外在碼率為每一符號為3位元的情況下，相差籬柵編碼調變使用十六位元振幅相位偏移調變會比十六位元相位偏移調變的相差籬柵編碼調變以及籬柵編碼調變加相差編碼兩者皆有更大的最小距離和更好的錯誤率。

關鍵字

相差編碼 ； 籬柵編碼調變 ； 非同調檢測 ； 碼搜尋

並列摘要

Differential encoding (DE) is a classical technique at the transmitter that allows simple noncoherent detection at the receiver. On the other hand, Trellis-coded modulation (TCM) is a bandwidth efficient technique which offers reliable data transmission. In this paper, we consider TCM with DE for channel phase coherence over N = 2 symbols. Besides the well-known TCM followed by DE (called TCM-DE) for MPSK signals, we propose a new trellis coding extension of DE, called differential trellis coded modulation (DTCM). DTCM is TCM with DE defined in states where distinct states may have distinct DE functions. We propose design methods of DE functions for noncoherently non-catastrophic DTCM.

For both TCM-DE using MPSK signals and DTCM, we propose additive distance measures and set partitioning. Based on the proposed set partitioning, trellis codes are designed or searched and their minimum distances are analyzed. For data rate 2 bits/symbol, the obtained new codes outperform the original codes for both TCM-DE and DTCM, and the new codes of TCM-DE and DTCM have similar bit error rate. For data rate 3 bits/symbol, DTCM using 16APSK (amplitude phase-shift keying) has better minimum distance and BER than both TCM-DE and DTCM using 16PSK.

並列關鍵字

Differential encoding ； Trellis-coded modulation ； Noncoherent detection ； Code Searches

參考文獻

[1] R. Y. Wei and J. A. Ritcey, “Differential trellis coded modulation with state dependent mappings,”Asilomar Conference on Signals, Systems, and Computers, CA, USA, Nov. 2014.

[2] G. Ungerboeck, “Channel coding with multilevel/phase signals,” IEEE Trans. Inform. Theory, vol. 28, pp. 55-67, Jan. 1982.

[3] G. Ungerboeck, “Trellis-coded modulation with redundant signal sets-Part I: Introduction,” IEEE Commun. Mag., vo1. 25, no. 2, pp. 5-11, Feb. 1987.

[4] G. Ungerboeck, “Trellis-coded modulation with redundant signal sets-Part II: State of the art,” IEEE Commun. Mag., vo1. 25, no. 2, pp. 12-21, Feb. 1987.

[5] R. Y. Wei, “Differential encoding by a look-up table for quadrature-amplitude modulation,” IEEE Trans. Commun., vol. 59,pp. 84-94, Jan. 2011.