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標題: IEEE 802.11e 混合協調功能通道控制存取之效能增強
Improving Performance in IEEE 802.11e HCF Channel Controlled Access
作者: 周磊
Chou, Lei
關鍵字: 802.11e;802.11;HCCA;admission control;混合協調功能通道控制存取;允入控制
出版社: 電機工程學系所
引用: [1]IEEE 802.11 WG, Reference number ISO/IEC 8802-11: 1999(E) IEEE Std 802.11, 1999 edition. International Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications,” 1999. [2]IEEE 802.11 WG, Draft Supplement to Standard for Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - “Part 11: Wireless Medium Access Control (MAC) and Physical Layer (PHY) specifications: Amendment: Medium Access Control (MAC) Quality of Service (QoS) Enhancements,” IEEE P802.11e/Draft 13.0, January, 2005. [3] Claudio Cicconetti, Giovanni Stea, Luciano Lenzini, Enzo Mingozzi, ”A Software Architecture for Simulating IEEE 802.11e HCCA” 3rd Internet Performance, Simulation, Monitoring and Measurement - IPS-MoMe 2005 - March 14-15, 2005 [4]Lu Yang, “P-HCCA: A New Scheme for Real-time Traffic with QoS in IEEE 802.11e Based Networks,” APAN (Asia-Pacific Advanced Network) Network Research Workshop 2004 [5]Javier del Prado Pavón and Sai Shankar N, “Impact of Frame Size, Number of Stations and Mobility on the Throughput Performance of IEEE 802.11e,” IEEE WCNC 2004, Georgia, USA [6]L. W. Lim, R. Malik, P. Y. Tan, C. Apichaichalermwongse, K. Ando and Y. Harada, “A QoS Scheduler for IEEE 802.11e WLANs,” IEEE CONSUMER COMMUNICATIONS AND NETWORKING CONFERENCE (CCNC), 2004 [7]Dennis Pong and Tim Moors, “Call Admission Control for IEEE 802.11 Contention Access Mechanism,” Proc. Globecom 2003, pp. 174-8, Dec. 1-5, 2003 [8]Yang Xian and Haizhon Li, “Local Data Control and Admission Control for QoS Support in Wireless Ad Hoc Networks,” IEEE. Transaction on Vehicular Technology (VT), 53(5):1558-1572, Sep 2004. [9]Grilo A., Macedo M., and Nunes M, “A Scheduling Algorithm for QoS Support in IEEE 802.11e Networks,” IEEE Wireless Communications, pp. 36-43, June 2003 [10]Dimitris Skyrianoglou, Nikos Passas and Apostolis Salkintzis, “Traffic Scheduling in IEEE 802.11e Networks Based on Actual Requirements,” Radio Network Management '04 (RNM ‘04), Athens on the 27th and 28th of May 2004. [11]Pierre Ansel, Qiang Ni, and Thierry Turletti. "FHCF: An Efficient Scheduling Scheme for IEEE 802.11e". Accepted to appear in ACM/Kluwer Journal on Mobile Networks and Applications (MONET), Special Issue on Modeling and Optimization in Wireless and Mobile Networks, 2005. [12] Claudio Cicconetti, Enzo Mingozzi, Giovanni Stea, “An Integrated Framework for Enabling Effective Data Collection and Statistical Analysis with ns2” Workshop on ns-2: the IP network simulator (WNS2) Pisa, Italy, October 10, 2006. Article No. 11 [13] The Network Simulator - ns-2 [14] Ns2HCCA Documentation -
無線區域網路技術的發展,增加了網際網路使用的便利性,此外多媒體資料的盛行,服務品質 (QoS) 的需求也愈顯現其重要性。然而,IEEE 802.11 MAC WLAN 傳輸協定,並無法保證傳送即時性多媒體資料時,無線區域網路所提供的服務品質。IEEE 802.11 Task Group E提出IEEE 802.11e QoS MAC 協定,用以確保多媒體應用的服務品質,其中混合式協調功能(Hybrid Coordination Function,HCF),包括了以輪詢為基礎的HCF通道存取機制(HCF Channel Controled Access,HCCA)和以分散競爭為基礎的增強式分散通道存取機制(Enhanced Distributed Channel Access,EDCA)。
在IEEE 802.11e 提供的HCCA允入控制範例中,使用了傳輸速度最小值做為參數值,但實際傳輸速度會因行動節點(Station,STA)與AP (Access Point) 距離的不同而有所差異,因而影響STA允入的數量。另外由於HCCA採用輪詢機制,較適合傳送有固定性傳輸速率(CBR) 的資料流,但在變動傳輸速率(VBR) 環境下的效能卻不太理想。
在本篇論文中,我們採用更精確計算傳輸速度演算法,改進原本的允入控制計算,增加STA的允入數量,同時採用動態延伸服務區間(Service Interval,SI)的策略,以使HCCA的架構對於變動傳輸速率的資料流有更好的適應性。藉由使用Network Simulation 2 (NS2)的模擬,我們也證實在頻寬與封包延遲、延遲抖動上都有相當程度的改善。

The development of the Wireless LAN technology has increased the convenience of the using internet. Besides, QoS (Quality of Service) demand emerges due to the popularity of multimedia traffic. However, it can not ensure the QoS offered in the Wireless LAN while transmission real-time multimedia data in existing IEEE 802.11 MAC Wireless LAN. IEEE 802.11 Task Group E bring up the IEEE 802.11e QoS MAC Protocol to ensure the QoS of the multimedia application. Hybrid Coordination Function (HCF) among this protocol comprehends HCF Channel Controlled Access (HCCA) based on polling and Enhanced Distributed Channel Access (EDCA) based on distributed contention.
The standard of HCCA admission control example as IEEE 802.11e offered, uses the Minimum Physical Rate as one of parameter value. But the Physical Rate will be changed according to the distance between mobile station and access point, and will affect stations to admit the amount. Besides, as a result of adopting polling scheme, HCCA suits to transmit the data flow in Constant Bit Rate (CBR), but it have a worse efficacy in Variable Bit Rate (VBR).
In this thesis, we take a more accurate transmission rate algorithm to amend the original admission control arithmetic, and increase the amount of stations to admit. At the same time, we take the tactic of dynamic extending Service Interval (SI) for making a better adjustability to VBR data flow in HCCA. By the simulation of Network Simulation 2 (NS2), we can prove a lot of improvement for Bandwidth, Package Delay and Delay Jitter.
其他識別: U0005-2108200716532200
Appears in Collections:電機工程學系所

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