應用於IEEE802.16都會型網路下之可適性資源排程機制

在無線的通訊網路架構中的資源限制較有線的網路大，在無線通訊網路中的排程設計與網路資源管理和通訊排程有密切的關係，妥善分配資源的排程方式可以達到提升系統效能的目的並且滿足不同的QoS需求。IEEE802.16中，排程的機制是根據基地台的下行（Downlink）及上行（Uplink）排程器進行通道頻寬的分配，依照排程決定每個訊框的通道資源需要替哪些連線進行資料服務，將結果放入DL_MAP及UL_MAP訊息之中，並且透過DL_MAP和UL_MAP訊息，告知所有網路中的用戶端（SS）在此訊框中通道資源的分配情況，各用戶端依據分配情形進行相對應的Burst接收及傳送動作。在傳統的頻寬資源配置方式，通常是對已經在佇列內等待的封包作為分配依據，分配時間點只考慮排程器在完成計算DL_MAP及UL_MAP訊息之前，當此訊框頻寬未完全配置時，其餘時間系統是處於等待的情況。但封包的到達是一種連續的行為，所以在進行Burst傳送及接收時，封包還是陸陸續續地到達各連線佇列中，但這些封包卻不能即時的得到處理，需等待到下一個訊框。所以本論文提出了一個資源排程機制，在有限的網路資源中用來提升系統的效能，並且也能同時滿足各類型的QoS需求條件。

關鍵字

IEEE802.16 ；服務品質；資源；排程

並列摘要

Radio resource management issue in wireless network is much stricter than in backbone network. The scheduling scheme in wireless network and resource management is closely related, and proper scheduling method for allocating resources can achieve higher system performance and satisfy different QoS requirement. In IEEE802.16 system, the bandwidth is allocated by the Downlink & Uplink scheduler. All Subscriber Stations know when they should send or receive by DL_MAP and UP_MAP. For most existing schedulers, the bandwidth is allocated using the minimum reserved rate maximum sustained rate. If the allocated bandwidth of one queue has reached the maximum sustained rate, there will be no more bandwidth given to it. However, for some light loaded system, there may be some free slots left after the scheduler assigns slots to all packets in queue. Those packets arriving after the scheduling will wait until next frame although there are free slots available.So, we have proposed a resource scheduling scheme can achieve high system throughput and fulfill QoS requirements for all types of services.

並列關鍵字

IEEE802.16 ； Quality of Service (QoS) ； Resource ； Scheduling

參考文獻

[1] Ying Jun Zhang, Letaief, K.B., “An efficient resource-allocation scheme for spatial multiuser access in MIMO/OFDM systems,” IEEE Transactions on Communications , vol. 53, no. 1, pp. 107–116, Jan. 2005.

[9] Y. Ben-Shimol, I. Kitroser, Y. Dinitz, “Two-Dimensional Mapping for Wireless OFDMA Systems,” IEEE Transactions on Broadcasting, vol.52 , Issue:3 , pp. 388 – 396, 2006.

[10] T. Ohseki, M. Morita, T. Inoue, “Burst Construction and Packet Mapping Scheme for OFDMA Downlinks in IEEE 802.16 systems,” Proceedings of IEEE Global Telecommunications Conference, 2007. GLOBECOM '07, pp. 4307 – 4311, 2007.

[11] C. So-In, R. Jain, A.-K. Al Tamimi, “eOCSA: An Algorithm for Burst Mapping with Strict QoS Requirements in IEEE 802.16e Mobile WiMAX Networks,” Proceedings of 2nd IFIP Wireless Days (WD), pp. 1 – 5, 2009.

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應用於IEEE802.16都會型網路下之可適性資源排程機制

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