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題 名 | The Study of Channel Assignment in Microcellular Mobile Communication Networks |
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作 者 | 曾志成; | 書刊名 | 景文技術學院學報 |
卷 期 | 10:2 2000.04[民89.04] |
頁 次 | 頁153-164 |
分類號 | 448.82 |
關鍵詞 | 頻道; 呼叫; Channel assignment; Handoff; Guard channel; Preemptive; Non-preemptive; Dwell time; Cost function; |
語 文 | 英文(English) |
中文摘要 | 由於頻道數目之限制,面對日益增加的行動通信訊務量,如何使頻道的使用率提 高便成為一個重要的議題。本篇論文中,我們以七細胞的系統環境來考慮此一問題,並將交 遞區域定義成為一個矩形,且利用它來做為判斷鄰近細胞之一般呼叫是否會交遞至中心細胞 的準則, 並計算交遞呼叫的行動臺在交遞區域內的停留時間。 我們將非先佔式( non-preemptive )與先佔式( preemptive )頻道服務方法應用到雙佇列與單佇列模型中 而發展出四種頻道分配策略, 分別是: 雙佇列非先佔式方案( Double Queue with Non-preemptive Priority Scheme, DQNP ), 雙佇列先佔式方案( Double Queue with Preemptive Priority Scheme, DQP ), 單佇列非先佔式方案( Single Queue with Non-preemptive Priority Scheme, SQNP )及單佇列先佔式方案( Single Queue with Preemptive Priority Scheme, SQP )。本論文將原始呼叫分成緊急呼叫與一般呼叫,並分 別的考慮其對系統之影響。 因為緊急呼叫的特殊特性, 我們利用保護頻道之觀念,保留了 Ce 個頻道專供緊急呼叫使用,稱為緊急保護頻道。藉此來降低緊急呼叫之阻斷機率。 最後 ,我們將本研究的結果與 FIFO 方案比較,結果顯示,本研究所提之方案皆優於 FIFO 方案 ,其順序為 SQP、DQP、SQNP、DQNP 及 FIFO。因此,SQP 實屬一可行之頻率分配策略。 |
英文摘要 | A seven-cell microcellular mobile communication system is considered in this paper for the study of channel assignment strategies. In order to calculate the probability that a call generated in neighboring cells will be handed off to the target cell, the handoff region is defined as a rectangular between cell boundaries. Using this definition, the duration that handoff calls stay in this region, i.e. the dwell time, can be computed. Both the preemptive and non-preemptive service disciplines are employed in the double queue and the single queue models. The impacts of emergency calls on the system performance are also assessed by using guard channels. Performance measures of the above schemes are presented and compared with that of the FIFO scheme and the results show that the single queue with preemptive scheme is a better channel assignment strategy than the others. |
本系統中英文摘要資訊取自各篇刊載內容。