網路電話(Voice over IP, VoIP)提供網際網路使用者低成本的語音通訊服務，近年來已發展成為網際網路上一個相當重要的應用。行動隨意接取網路(Mobile Ad Hoc Access Network, MAHAN)乃藉由節點間多躍(Multi-hop)方式轉送以延伸網路服務涵蓋範圍，使網路電話服務不受存取點(Access Point, AP)的服務範圍或是通訊死角的限制。但是在網路電話的語音封包中，若網路協定的標頭長度比酬載長度還要大，將會造成頻寬使用效率不佳，使得在頻寬資源有限的MAHAN中使用網路電話服務將會大幅降低流通量(Throughput)。本論文研究網路電話服務應用於MAHAN環境下的頻寬效率問題。
本研究以SIP(Session Initiation Protocol)網路電話服務應用於MAHAN網路，設計一套多工與解多工機制(Multiplexing and De-Multiplexing, MDM)的方法，適用於行動隨意接取網路。當網路電話連線建立成功之後，語音封包中的IP/UDP標頭不會改變，所以將語音封包多工封裝後一起傳送，即可減少IP/UDP標頭重複的花費和多躍方式所花費的頻寬，進而改善網路電話的服務品質。我們根據封包的傳送路徑提出兩種選擇多工器與解多工器法則，一種是選擇正在進行會談的使用者，稱為MDM之會談使用者(MDM-Active User Only, MDM-AUO)，另一種選擇法則是依據邏輯拓墣分支點，稱為MDM之邏輯拓墣分支點(MDM-Cross Node Only, MDM-CNO)。假設IEEE 802.11b只使用11Mbps與5.5Mbps資料速率的MAHAN網路環境下提供網路電話服務，在考量封包遺失率1%與可容忍延遲時間為75ms的條件下，MDM-CNO機制比未使用MDM機制與MDM-AUO機制提升20%的會談數。

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