co-DRR: 在無線區域網路上整合上傳與下傳排程的頻寬管理

Abstract

在有線網路瓶頸連線上已經存在許多有效利用頻寬資源的分配方式。隨著無線網路環境快速的演進，有效分配目前無線區域網路IEEE 802.11標準環境下的頻寬是一個值得探討的議題。但目前針對無線頻寬管理議題的討論多為最佳化多媒體資料傳輸、單獨上傳或下傳的頻寬管理或是與IEEE 802.11標凖不相容的頻寬管理方式。因此我們提出一個利用deficit round robin (DRR)和distributed-DRR (DDRR)演算法整合上下傳的頻寬流量計算且相容於IEEE 802.11標準的頻寬管理機制以保障每一個使用者獲得的頻寬。並使用PCF mode機制，利用非競爭時期來補足競爭時期所造成的不公平現象。從模擬的結果可以看出，在多台機器(100台)或是高位元錯誤率(0.0001)的測試環境下，分配給每位使用者的上下傳的頻寬量不但能達到長期的公平性，且延展性極佳。

Bandwidth management over wired bottleneck links has been an effective method to utilize network resources. For the rapidly emerging Wireless Local Area Network (WLAN) with IEEE 802.11 standard, bandwidth management over the bottlenecked WLAN becomes a new issue. Most possible existing solutions only exclusively focus on optimizing multimedia traffic, pure downlink/uplink fairness, or are incompatible with IEEE 802.11. This study proposes a cooperative deficit round robin (co-DRR), an IEEE 802.11-compatible host-based fair scheduling algorithm based on the deficit round robin (DRR) and distributed-DRR (DDRR) schemes, cooperating the uplink and downlink quantum calculations. With the PCF mode, utilize the contention-free period to complement the unfairness of contention period. With 100 mobile hosts or 0.0001 high bit error rate, simulation results show uplink and downlink bandwidth allocated for hosts not only achieves long-term fairness (CoV< 0.01) but also scales well.