無線區域網路中以多重輪詢為基礎的排程演算法

Abstract

為了在無線區域網路中提供即時性串流更佳的服務品質，IEEE 802.11e 標準制定團隊，提供了混合協調功能(HCF, Hybrid coordination Function)，其中一種非競爭的存取模式HCCA(HCF Controlled Channel Access)中使用輪詢(Polling)的機制的，如何在這機制下設定一個好的排程演算法來決定每個工作站的服務間隔(Service Interval)和每次可以得到的傳送機會(TXOP)就是一個重要的課題。 這篇文章提出三種多重輪詢的方法，配合回報的機制，精確地分配傳送機會(TXOP)給每個工作站以符合其需要。無論是對於固定位元速率(CBR)或是變動位元速率(VBR)的串流，皆能更加有效地提升系統的效能。

For QoS (Quality of Service) requirements of real-time traffic on WLAN, IEEE 802.11 Task Group E provides HCF (Hybrid Coordination Function),which consists an contention-free access mode named HCCA(HCF control channel access) adopting polling mechanism. How to set a good schedule algorithm to decide the service interval and the TXOP duration of STAs is an important issue. In this paper we present three multipolling algorithms, with the response mechanism, allocate the TXOP duration of STAs accurately for the real requirement. The algorithm provides better the performance of CBR and VBR traffic.