蜂巢式個人通訊服務系統中通道借用指派策略之研究

Abstract

在蜂巢式行動通訊系統中，通道指派策略的優劣與否可由頻譜的使用效率 來決定，而頻譜的使用效率則可由發話阻塞機率及強迫通話中斷機率來衡 量。本篇論文將探討並評估在蜂巢式個人通訊服務系統中通道借用指派策 略的效能。首先，我們將通道借用指派策略設定為一種保護換手作用的方 法，同時提出一種近似的方法來分析此種系統的效能。並觀察出通道借用 指派策略對於換手作用的影響。我們也考慮通道借用策略同時使用在新來 呼叫及交手呼叫時的情形。而在通道借用指派策略中呼叫佇列及截止優先 權也在本篇論文的討論範圍中。我們的目的是分析通道借用指派策略的效 能，同時在一特定的系統效能評估標準下，找出新來呼叫的佇列長度、交 手呼叫的佇列長度及保護頻道數目的最佳組合。 In the cellular mobile communication system, whether a channel assignment strategy is good or not is determined by the utilization of spectrum. And the utilization of spectrum can be measured by the blocking probability and the forced termination probability. The thesis studies the performance of a channel borrowing assignment strategy for a cellular-based PCS system. First, we adopt the channel borrowing strategy as a protection scheme for handoff and propose an approximated method to analyze the system performance. The effect of the channel borrowing strategy on handoff is investigated. Ane we also consider the channel borrowing strategy for both new calls and handoff calls; the call queueing and cutoff priority used in the channel borrowing strategy are discussed. Our objective is to measure the performance of the channel borrowing strategy to determine the optimal combination of the queue lengths for both new and handoff calls and the number of guard channels given a specified system performance criterion.