Resource Allocation with Proportional Fairness in OFDMA-based DF Relay Networks

• Main Authors: Wei-chun Liao, 廖瑋鈞
• Other Authors: Wen-hsien Fang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/47317474247355323130

碩士 === 國立臺灣科技大學 === 電子工程系 === 100 === The orthogonal frequency division multiple access (OFDMA) sys- tems can offer high spectral efficiency and mitigate the problem of frequency-selective fadings, and have received lots of attention re- cently. Cooperative networks, meanwhile, can form a distributed antenna array and provide the spatial diversity gains to enhance the converge, better performance can be reached by combining their in- dividual advantages. In this thesis, we consider resource allocation with proportional fairness (PF) in the OFDMA-based decode-and-forward (DF) relay networks. In order to attain the fairness of the relay nodes, we pur- pose an algorithm which jointly consider relay selection and power allocation. Because the formulated primal problem is nondetermin- istic polynomial time-complete, we first make continuous relaxation, then solve the dual problem by dual decomposition method. The near optimal solution can then be found by the KKT condition. Moreover, we also take into consideration the subcarrier matching between the relay nodes to the source nodes and the relay nodes to the destination nodes to further enhance the overall performance. Since the algorithm proposed was iterative, it calls for lots for computational complexity. To alleviate this setback, we also first impose each user to have the minimum required data rate before proceeding the recursive. As such, the computational load can be substantially mitigated. Simulation results show that the proposed method provides both higher throughput and better fairness among relay nodes in comparison with previous algorithms.