基於最小功率的適應性資源配置演算法於正交分頻多工存取系統下效能改進

Performance Improvement of Adaptive Resource Allocation Algorithm Based on Minimum Power Criterion in OFDMA Systems

邱盈瑄(Ying-Hsuan Chiu)

指導教授 ： 呂振森

國立臺北科技大學/機電學院/電機工程系所/碩士(2010年)

摘要

基於最小功率的適應性資源配置演算法是在正交分頻多工存取系統下，限制每位使用者的比例速率及固定總傳輸功率條件下，先考量各使用者的傳輸速率比及遠近效應等兩種因素分配各使用者子載波數，再以最小傳輸功率為基礎來配置子載波給各使用者的適應性資源配置演算法。相較於其它適應性資源配置演算法，其具有高總傳輸容量的優點，但其複雜度在使用者人數增加時，會有偏高的趨勢。本論文主要針對此一演算法的複雜度做進一步改良，以通道中最小傳輸功率的平均為基礎設立一門檻值，去除掉情況較差的子載波，進而改進子載波配置速度。由電腦模擬顯示，此一改良式的適應性資源配置演算法和其他三種演算法比較，在不影響整體傳輸容量的情況下，能夠有效降低複雜度。

關鍵字

正交分頻多工存取、比例速率限制 ； 適應性資源配置 ； 子載波配置 ； 功率配置

並列摘要

The adaptive resource allocation algorithm based on minimum power criterion in OFDMA system is an algorithm with both proportional rate constraint and fixed total user’s power. First, the number of subcarriers for each user is determined by considering the factors of both proportional rate constraint and near-far effect. Then the subcarriers for each user are allocated based on minimum power criterion. Compared with other algorithms, this algorithm has high transmission capacity, but the complexity would increase when the number of users increases. This thesis mainly focuses on improving the complexity of this algorithm. We set up a threshold that based on the average of minimum transmission power for each subcarriers. Thus some subcarriers with lower SNR will be eliminated to improve the speed of subcarrier allocation. The computer simulation shows that our proposed algorithm, compared with other three algorithms, can efficiently reduce the complexity without influencing the capacity of transmission.

並列關鍵字

OFDMA ； proportional rate constraint ； adaptive resource allocation ； subcarrier allocation

參考文獻

1. H. Fujii and T. Asai, " Iterative equalization of multipath components whose delay exceeds GI for OFDM transmission," IEEE Vehicular Technology Conference, vol. 1, pp. 520-524, 2004.

4. S. Haykin, Communication Systems, Fourth Edition, Wiley, 2001.

5. L. Nuaymi, WiMAX Technology for Broadband Wireless Access, John Wiley & Sons, 2007.

6. W. Rhee and J. M. Cioffi , "Increase in capacity of multiuser OFDM system using dynamic subchannel allocation," IEEE Vehicular Technology Conference , vol. 2, pp. 1085-1089, 2000.

7. Z. Shen, J. G. Andrews and B. L. Evens, "Adaptive resource allocation in multiuser OFDM systems with proportional rate constraints," IEEE Transactions on Wireless Communication, vol. 4, no. 6, pp. 2726-2737, 2005.