A high performance resource allocation algorithm using channel conditions in downlink of OFDMA networks

Abstract

Modern wireless and mobile cellular networks like Wireless LANs, sensor networks and mobile wireless cellular networks are using Orthogonal Frequency Division Multiple Access (OFDMA) as the access scheme. In Orthogonal Frequency Division Multiple Access based networks, the resources like bandwidth and power have to be properly allocated to optimize the performance of the wireless networks. Factors like signal-to-noise ratio, inter cell interference, distance from the mobile node to the base station, user mobility will affect the performance of the network. Various algorithms have been implemented to optimize the resource allocation in OFDMA based wireless cellular networks. Margin adaptive algorithms tend to optimize the transmit power constrained by network throughput. Rate adaptive algorithms tend to optimize the bandwidth constrained by transmit power. The feedback information including channel-quality-information, frequency used helps in resource allocation. In this paper, a simple and fast algorithm for resource allocation is proposed which will favor the nodes with better channel quality over the nodes with poor channel quality. The proposed method calculates the median of the channel quality information and nodes with better channel quality are favored comparing to the nodes with poor channel quality. While this improves performance, the fairness will be affected. To overcome this, the algorithm provides a provision to favor fairness over throughput. The algorithm performance is evaluated under different channel conditions and found to improve the performance by up to 30% over existing algorithms.