MS 在RS系統的路徑重新選擇機制

Abstract

Wimax (802.16e)是一種可以在城市範圍大小裡能夠提供眾多使用者，以及在這大範圍裡提供高速資料傳輸的技術。雖然有很好的科技來支援這個技術，仍然有許多問題需要去克服，像是如何延長手機電池的待機和使用時間，如何在高速移動中取得高速傳輸的平衡，以及如何提高覆蓋範圍，都是急待解決的問題。然而這些問題都可以藉著導入Relay Station來改善。導入Relay Station有兩個主要的好處：增加訊號覆蓋範圍和提高訊號傳輸量。但是隨著Relay Station數目的增加也使得Handover變的比以前來的更頻繁。而有些不必要的Handover會造成系統的額外負荷以致於訊號傳輸量並沒有提高，並且造成整個系統資源的浪費和效率的降低。在本篇論文中，一個新的路徑選擇機制將被導入Handover中來解決Ping-Pong Effect。經過簡單的模擬後，這個路徑選擇機制不但可以降低Ping-Pong Effect並且提高在Handover之後的SINR改善的量。

WiMAX (802.16e) is technically capable of offering city-wide broadband connections to a high number of mobile terminals and provides high speed transmission over large area. The technology has strong industrial support, however a number of challenges remain to be resolved. Major concerns include battery life for mobile terminals, balancing support for high velocity and high data-rate, and increasing area coverage. Relay Station technology is a promising approach to address these challenges. The two major benefits of Relay Station employment are coverage extension and throughput enhancement. As the number of Relay Stations increases, the handover scenarios happen much more often than that of non-RS system. The Ping-Pong effect increases the system loading and may not enhance the system throughput. Some unnecessary handovers also may result in the waste of resource and decreases the efficiency. In this thesis, a path reselection mechanism will be introduced to resolve the Ping-Pong effect and throughput issues. This method is implemented in the simulation whose result shows the Ping-Pong handover reduction and higher SINR improvement after handover by using this proposed path reselection mechanism.