為了進一步支援無線網路上的服務品質(QoS)，IEEE 802.11e通訊協定目前正在制訂中。其提供兩種媒介存取方式，一為基礎的進階分散存取(EDCA)，另一種是建構在進階分散存取下的混合控制存取(HCCA)。802.11e中，藉由不同的訊框間隔(IFS)與競爭視窗(CW)相關參數的設定以區隔不同的存取等級(AC)。為了在802.11e網路下進一步的發展有效的服務品質管理機制，我們提出了一個數學模型以分析在進階分散存取網路下所使用的頻寬與媒體存取層所延遲的時間。在這個模型下，每個站台可以支援多個不同等級的資料流(聲音/影音與資料)。透過這個數學模型，允入控制與資源管理可以很容易實現，也可以支援不同應用程式的不同需求。 / For supporting Quality of Service (QoS) for wireless networks, the IEEE 802.11 Task Group E currently defines enhancements to the IEEE 802.11 MAC, called 802.11e. The IEEE 802.11e provides two mechanisms for the support of applications with QoS requirements, namely, Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA). EDCA mechanism defines four access categories (ACs) that provide support for the delivery of traffic with user priorities. Different AC uses various Inter-Frame Space (IFS) and Contention Window (CW) parameters. In order to further develop efficient QoS management for the IEEE 802.11e networks, we propose an analytical model to evaluate throughput and MAC delay of the basic access method of the IEEE 802.11e - EDCA. Our Markov chains consider the situation of different multimedia (voice/video and data) traffic flows in a mobile station. This is improved from previous work, and closer to real usage scenarios. The correctness of our analysis has been validated via simulation results. Throughout our model, call admission control (CAC) and resource management can be easily applied, and thus QoS for hybrid requirements is supported.
| Identifer | oai:union.ndltd.org:CHENGCHI/G0917530071 |
| Creators | 吳明儒, Wu,Ming-Ju |
| Publisher | 國立政治大學 |
| Source Sets | National Chengchi University Libraries |
| Language | 英文 |
| Detected Language | English |
| Type | text |
| Rights | Copyright © nccu library on behalf of the copyright holders |
Page generated in 0.0014 seconds