應用於影像通訊之細胞漏失恢復系統的設計與製作

Abstract

在寬頻整合服務數位網路中，非同步傳輸模式被視為最有希望的傳輸技術 。由於影像處理及網路的快速發展，影像資訊將在未來電信系統佔重要部 份。由於影像處理及網路的快速發展，影像資訊將在未來電信系統佔重要 部份。為了要整合影像到非同步傳輸模式網路中，我們設計了非同步傳輸 模式適應層,非同步傳輸模式層的電路以及細胞漏失恢復系統。細胞漏失 是影響影像服務品質的重要因素。以往的設計以細胞為處理的單位，但是 由於繞線使得它不太實際。我們以字為處理的單位，可以至少節省百分之 四十的面積。我們提出了環狀佇列以及多重管線的結構以符合高速的要求 。也提出一演算法以偵測細胞漏失及誤傳的情形。結果顯示我們的雛型系 統可以容忍連續四個細胞漏失及誤傳的情形。我們的演算法的錯誤決定機 率也比傳統小很多。 In the Broadband Integrated Services Digital Network (B-ISDN), asynchronous transfer mode (ATM) are expected to be the most promising transfer technology. Due to the rapid evolution in the area of image processing and networking, video information will be an important part of tomorrow's telecommunication system. In order to integrate video into ATM networks, we design ATM Adaptation Layer (AAL), ATM layer circuits and cell loss recovery system. Cell loss is a critical factor which will degrade the quality of video service. Conventional designs use cell-wise processing but it is impractical to implement because of routing overhead. Our work,by using word-wise processing, have saved at least 40% area for implementation. We also propose cyclic queue and multi-pipeline structures to meet high speed requirement and propose an algorithm to detect cell loss and mis-insertion conditions. Results indicate that our prototype system can tolerate four consecutive cell loss and mis-insertion conditions.The probability of erroneous decision for our algorithm is much less than conventional ones.