隨著無線網路技術日漸成熟，越來越多有關即時資料及應用的傳送在無線網路環境上，如隨選視訊、視訊會議等。在下一代的高速無線網路中，如何對及時多媒體應用能提供服務品質(QoS)的保證將是一個重要的議題。雖然對於如何提供服務品質保證的議題在有線網路中已經早已存在了，但這項工作由於因無線網路的頻寬缺乏、具行動性、及具高錯誤率等特性，造成了在提供服務品質保證時的一個挑戰。
對於如何減少行動台在做交遞換手(handoff)時因對方的可用頻寬不足而造成通訊中斷是非常重要的。允入控制機制便是對於如何保證即時且連續的多媒體傳輸的服務品質是一個關鍵。在本論文中，我們將提出一套新的允入控制機制於無線網路。此機制整合了頻寬保留與重置策略，且將更有效地達成降低新連線或交遞換手時的失敗機率並同時提升了頻寬的使用率。此外，在我們所提出的演算法中，在做資源配置時是同時也有考量到多重類別(multi-class)與公平性的觀點。
並在經過許多的模擬實驗結果顯示：我們提出的機制在提供多媒體服務品質保證上的效果是優於之前別人所提出的方法。

With the maturity of wireless network technologies, more and more real-time data and applications, such as video on demand, video teleconferencing, are being transmitted on the wireless environment. In the next generation high-speed wireless networks, the important issue is how to provide quality-of-service (QoS) guarantees as they are expected to support multimedia applications. Although the QoS provisioning problem arises in wireline network as well, scarcity of bandwidth, mobility of hosts, high bit error rate, etc., provisioning a challenging task in wireless network.
It is important to reduce the dropping rate caused by lack of available bandwidth in the handoff target cell. Call admission control is a key component for real-time, continuous media connections to guarantee QoS for these applications. In this thesis, we proposed a new call admission control scheme in wireless network. The scheme is integration bandwidth reservation and reallocation strategy and more effective to reach that decrease the handoff call dropping probability (CDP), new call blocking probability (CBP) and increase the bandwidth utilization (BU). Furthermore, our scheme also considered aspects of multi-class and fairness when the system allocated resource to calls. Extensive simulation results show that our scheme outperforms the best previously known schemes to provide QoS guarantees for multimedia traffic.

中文摘要…………………………………………………………..2
Abstract…………………………………………………………3
Chapter 1 ：Introduction…………………………………………………….6
Chapter 2 ： Related Work………………………………………………………….10
2.1 Strategies for Handoff Detection…………………………………………..10
2.1.1 Mobile-Controlled Handoff……………………………………….11
2.1.2 Network-Controlled Handoff……………………………………..11
2.1.3 Mobile-Assisted Handoff……………………………………...….11
2.2 Strategies for Channel Assignment…………….………………………….13
2.2.1 Non-prioritized scheme…………………………………………13
2.2.2 The Reserved Channel Scheme…………………………………14
2.2.3 Queuing Priority Scheme…………………………………………15
2.2.4 Sub-rating Scheme………………………………………………..16
Chapter 3 ： Relevant Literature Discussion……………………………………….17
3.1 Bandwidth Reservation Based CAC………………………………………18
3.1.1 Fixed Reservation Strategy……………………………………..18
3.1.2 Adaptive Reservation Strategy………………………………….20
3.2 Bandwidth Reallocation Based CAC……………………………………...27
Chapter 4 ： Proposed Method…………………………………………………….29
4.1 Designing Issue…………………………………………………………….29
4.2 Bandwidth Reservation strategy…………………………………………..32
4.3 Bandwidth Reallocation Strategy…………………………………………37
4.4 Admission control scheme………………………………………………...41
Chapter 5 ： Simulation Results and Discussion……………………………………44
Chapter 6 ： Conclusion…………………………………………………………….52
Reference …….………………………………………………………………………54

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