蜂巢式通訊系統之資源配置方法

Abstract

近年來，由於行動用戶的急速增加，擴增蜂巢式行動通訊系統容量之需求極為殷切；如何有效利用極珍貴的無線頻道資源來提昇蜂巢式行動通訊系統的系統容量是一個非常重要的工程課題。在本論文中，我們對於蜂巢式通訊系統之資源配置策略做了廣泛的研究。其研究的課題包括了：階層式蜂巢架構(Hierarchical Cellular Structure)、優先權策略(Priority Strategy)、分工方法(Duplexing Scheme)與多工/多重擷取機制(Multiplexing/Multiple Access Mechanism)。我們首先研究階層式蜂巢行動通訊系統中之優先權頻道配置策略。階層式蜂巢架構是設計來獲得微蜂巢(Microcell)系統與巨蜂巢(Macrocell)系統的優點。在該系統中，我們研究了保護頻道(Guard Channel)與佇列策略(Queueing)對於系統效能的影響。再來，我們探討分工策略與多重擷取機制對系統效能的影響。可變分配的分工方法(Variable Partition Duplexing)被提出來使用在封包保護多重擷取(Packet Reservation Multiple Access, PRMA)之上。可變分配的多工方法是設計來利用電話交談活動中之訊務特性。延長保留時段(Enlarged Reservation Duration)的提出用來進一步增進PRMA系統的效能。最後，我們研究CDMA/TDD系統之資源分配方法對於以新到呼叫阻塞率和資料毀損率為參考基準的系統效能之影響。固定分配和動態分配的方法在文中被提出來用在CDMA/TDD之上，並且他們的系統效能在文中被比較分析。我們成功地分析了上述的資源配置方法，並且透過電腦模擬來檢驗這些分析方法的正當性。從這些數值結果顯示，我們所提的資源配置方法確實可以有效提昇蜂巢式行動通訊系統之系統效能。

Designing resource allocation schemes for cellular systems is one of important engineering issues for improving spectrum efficiency, because of tremendous growth of the mobile user population. In this dissertation, we study resource allocation schemes, including hierarchical cellular structure, priority strategies, duplexing scheme, and multiplexing/multiple access mechanism, for cellular communications systems. We first analyze a hierarchical cellular system with priority channel assignment schemes. Hierarchical cellular systems are designed to take the advantages of both microcell and macrocell systems. The effects of queueing schemes for new and handoff calls and guard channel scheme for handoff calls on the system performance are studied. And then, allocation schemes of duplexing scheme and multiplexing/multiple access mechanism are studied. Variable partition duplex scheme, which is designed to take the advantages of the nature of conversation activity, is proposed on packet reservation multiple access (PRMA). Enlarged reservation duration scheme is proposed to improve the PRMA system. Finally, we study the effects of ways to share the communication resource on the performance of CDMA/TDD systems in terms of outage probability and blocking probability. Dynamic and fixed allocated schemes are proposed for CDMA/TDD, and then their system performances are compaired and analyzed. We successfully analyze the above resource allocation schemes and verify the validity of these analyses by simulations. The numerical results show that our proposed resource allocation scuhemes indeed have some improvement on the performance of cellular communication systems.