無線網路使用MC-CDMA 技術之軟式移交佇列優先權演算法研究

Study on Queuing Priority Algorithm for Soft Handoff Using MC-CDMA in Wireless Networks

無線通訊技術是近年來廣受歡迎的技術，因為它解決有線網路受地形地物影響的限制。而移交管理是無線通訊系統的重要議題。本篇論文主要針對無線網路使用多重載送分碼多工存取（multi-carrier code division multiple access；MC-CDMA）的技術利用佇列優先權（queuing priority）的觀念來解決移交斷訊率（handoff call dropping ratio）過高的問題。我們提出一個高效率的適應性佇列優先權演算法（adapted queuing priority algorithm；AQPA），採用前後移交佇列的架構及應用剩餘價值（surplus value）的策略來解決移交管理的問題。系統將不同的服務連線訂定不同的優先權順序，每個移交連線使用相對優先權來接受服務。最後，透過模擬的方式與其他已提出的方法互相比較。AQPA演算法確實使輸出率（throughput）提高、軟式移交斷訊率、新連線阻塞率（new call blocking ratio）及系統連線拒絕率（call refusing ratio）顯著降低。AQPA的效能確實比其他方法優異。

Wireless communication has recently become a very popular technique; it eliminates the restriction that wired networks are subject to the influence of terrain and ground features. Handoff management is an important issue in wireless mobile communications. This paper aims at making use of the queuing priority concept to resolve a problem in which the handoff call dropping ratio is high in a wireless network using multi-carrier code division multiple access (MC-CDMA). The proposed method employs an efficiently adapted queuing priority algorithm (AQPA) which adopts a front and back handoff queuing structure and applies surplus value strategy to resolve the problem of handoff management. The system sets different priorities for all traffic types; each handoff call handles its own priority ordering. We compared the performance of other approaches with our scheme by simulation. The AQPA algorithm obviously increases system throughput and decreases the soft-handoff call dropping ratio, the new call blocking ratio, and the total call refusal ratio. The performance of AQPA is better than the other methods examined.