Mobile WiMAX系統之自適性通道容量規劃研究

網路由早期的有線網路演進到現在為人廣泛使用的無線網路，其服務可為電腦之間的無線傳輸以及手機之間的訊息溝通等應用，然而無線網路傳輸的服務已經由早期使用的文字傳輸型態，提昇到現今多媒體應用的服務等級，並且在WiMAX無線網路可同時支援高傳輸速率與高速移動的優勢之下，隨著多媒體應用環境的人口以及對於服務需求的快速成長，預估在短期內將會產生大量的WiMAX網路服務使用人口，在需要服務大量使用人口並且同時參雜多種不同服務類型(例如:通話、簡訊、影音)的情況下，如果沒有一套有效的機制來管理有限的系統容量資源，將會發生系統資源容量不敷使用的情況，因此系統需要一套有效的資源分配策略進行頻寬資源的管理與配置來滿足各種型態的服務流，同時藉由完備的資源管理策略也可以達到增加無線頻寬資源的使用效率的目標。在IEEE 802.16e標準中將各種不同的訊務歸類成五種不同QoS(Quality of Service)要求的服務類型來因應文字與多媒體資料流並存的網路環境，但對於資源管理方面卻並未具體描述其對於五種服務類型的通道配置方式以及資源管理方法，因此本研究著眼於包含多種QoS要求訊務的系統中提出一套適用於移動使用者的無線資源管理策略，考慮使用者使用在OFDMA實體層技術下，移動時所產生的換手(Handoff)與傳輸模式(Transmission Mode，TM)轉換事件對於QoS的影響，其目標為在有限的無線資源限制之下，滿足不同QoS要求的訊務並且有效提高整體容量資源利用率。管理策略中考慮了使用者的移動行為、傳輸的資料類型以及通道狀態等因素，並且利用自適性通道調變與編碼(AMC)對應的傳輸模式(TM)轉換技術、系統暫存(Buffer)語音資料保護頻道(Guard channel)等策略來達成最大化整體資源利用率的目標。最後透過數值分析與結果顯示本研究提出的無線資源管理策略不僅滿足了不同訊務QoS同時也將整體資源利用率大幅提升。

關鍵字

服務品質(QoS) ；全球微波互通存取介面(WiMAX) ；正交分頻多工存取(OFDMA) ；自適性調變與編碼(AMC) ；資源管理

並列摘要

In the recent year, wireless network is growing very fast. Wireless network can provide some application, such as computers transmit data and cell phone sending voice message. In the wireless service, the multimedia application requirements are increased rapidly. The WiMAX technology can take the advantage of high transmission rate and support high moving speed to provide the multimedia services to a large number of mobile subscribers (MS). In addition, the WiMAX technology also includes five types of service to satisfy the demand of huge number of mobile users. However, the wireless bandwidth resource (channel capacity) is limited. If the system want to provide great Quality of Service (QoS) content to a large number of users at the same time, then there must exist a complete management scheme to allocated the radio resource and promote the system resource utilization. However, IEEE 802.16 standard did not explicitly defined the detail of how to allocate radio resource for the five types of services. Consequently, in this paper, we proposed a radio source management scheme which can guarantee the QoS requirements and maximize the system resource utilization. Our research environment considered the OFDMA physical technology to discuss the influence of the QoS when the handoff and transmission mode (TM) even occur. Besides, we exploit adaptive modulation and coding (AMC) technology, system buffer and guard channel scheme to management the radio resource. The numerical results show that the proposed radio resource management scheme not only guaranteed the QoS (New call blocking probability and Call terminating probability) requirements but raised the system resource utilization.

並列關鍵字

Quality of service (QoS) ； Adaptive Modulation and Coding (AMC) ； Orthogonal Frequency Division Multiple Access (OFDMA) ； WiMAX ； Resource management

參考文獻

[22]. Jeffrey G. Andrews, Arunabha Ghosh, and Rias Muhamed, ” Fundamentals of WiMAX : Understanding Broadband Wireless Networking,” Chapter 3.22, Prentice Hall, 2007

[4]. Loutfi Nuaymi, WiMAX: Technology for Broadband Wireless Access, Wiley 2007.

[5]. Ali S. H., Lee K. D. and Leung V. C. M., “Dynamic resource allocation in OFDMA wireless metropolitan area networks,” IEEE Wireless Communications, vol. 14, no. 1, February 2007, pp. 6-13.

[6]. Lee K. D. and Leung V. C. M., “Capacity planning for group-mobile user in OFDMA wireless networks,” EURASIP Journal. Wireless Communications and Networking, vol. 2006, pp. 1-12.

[7]. Guerin R., “Queuing-blocking systems with two arrival streams and guarded channels,” IEEE Transaction on Communication, vol. 36, February 1988, pp. 153-163.

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Mobile WiMAX系統之自適性通道容量規劃研究

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