應用於行動影音之錯誤回復傳輸機制

An Error Recovery Transmission Mechanism for Mobile Multimedia

周業凱(Yeh-Kai Chou) ； 施啟煌(Chi-Huang Shih) ； 沈志聖(Chih-Sheng Shen)

《電腦與通訊》 155期 (2014/02) Pp. 5-12

摘要

本論文提出一個在無線與行動網路中調適品質的傳輸機制，乃採用子區塊結構的跨封包傳輸方法，目的在於解決行動網路影音品質不良的問題，現有的通道編碼技術雖已針對行動網路的資料傳輸具保護作用，然而在有限的頻寬限制條件下面對多種網路傳輸現象，包括網路壅塞與訊號錯誤等所導致的綜合性問題：資料回復效能不佳以及頻寬使用效率低落仍是通道編碼的主要缺陷之一。經由實驗分析，相較於現有的技術，所提方法能以子區塊的編解碼結構，動態適應於無線傳輸過程裡小資料量的訊號錯誤而達成較佳的頻寬使用效率，加以跨封包的傳輸模式能夠具備以下兩個特色以增進資料回復的效能：（1）不受網路可容許封包長度限制的影響；（2）可同時回復封包遺失與訊號錯誤此兩種主要的傳輸問題。

關鍵字

跨封包(Cross-packet) ； 通道編碼(Channel Coding) ； 向前糾錯碼(Forward Error Correction ； FEC) ； 錯誤回復(Error Recovery) ； 行動影音(Mobile Multimedia)

並列摘要

This paper presents a cross-packet channel coding mechanism using sub-block structure in wireless and mobile networks. In such a wireless transmission environment, challenges arise when the traditional channel coding mechanisms need to deal with both network congestion and signal errors under the limited bandwidth constraint. Therefore, the proposed mechanism aims at solving the corresponding problems of poor data recovery efficiency and low bandwidth utilization. Compared with the traditional mechanisms, the experimental results demonstrate that the proposed mechanism can achieve better bandwidth utilization by means of using sub-block coding structure to combat with small amount of transmission errors. Furthermore, the data recovery performance can be improved based on two following facts about the cross-packet transmission: (1) the channel coding capacity is beyond a single packet and (2) both congestion loss and transmission errors can be recovered.