WiMAX系統之雙層需求下的下行鏈路資源分配 演算法

Abstract

IEEE 802.16e 是一項著名的行動通訊規格，並使用正交分頻多工存取(OFDMA)作為實體層的傳輸方式。在OFDMA系統架構下，資源分配是很重要的部分。若能有效率分配二維資源(時間和頻率)給行動用戶就能提升通道使用率和資料傳輸量。本論文提出一個雙階級需求下的下行鏈路資源分配演算法，有3個主要的目的(1)考慮資源分配的單位為封包等級，(2)將需求分為兩種優先權資料。MUST資料為高優先權的資料;WISH資料為低優先權資料，(3)考慮需求使用的調變與編碼機制。我們將提出的演算法與雙階級需求對應演算法(2L-DMA)作比較，由模擬結果可知本論文提出的演算法可以提升21.9%的資料傳輸量，多服務6%~7%的高優先權資料，並減少約一半的資源分配所需的額外資訊。

IEEE 802.16e is a popular wireless communication technology, which use the OFDMA technology to achieve high data rate and reliability of physical layer (PHY) for wireless transmission. Resource allocation is an important part in the WiMAX system. It would improve channel utilization and throughput by allocating two-dimension (time and frequency) burst efficiently to each mobile user. In this thesis, we propose a downlink resource allocation algorithm for two-level request and it consists of three targets: (1) consider packet-level resource allocation; (2) classify urgent data as MUST data; classify non-urgent data as WISH data; and (3) consider MCS for each request. The goal of our proposed algorithm is to achieve high throughput, channel utilization, and reduce map overhead. We compare the performance of our proposed algorithm to 2L-DMA. Simulation results show that our proposed algorithm can enhance the throughput more 1.3Mbps than the throughput of 2L-DMA. Allocate the high priority data which is 6%-7% more than 2L-DMA. Besides, reduce almost half of the map overhead comparing to the one of 2L-DMA.