GA Optimized Multi - objective Function of Subcarrier, Bit and Power Allocation for Downlink OFDMA Cellular Systems

In this paper we present a technique for resource allocation in orthogonal Frequency Division Multiple Access (OFDMA) systems with a proportional rate constraint which is topical in 4G. This technique deals with compensation between the transmitted rate maximization and power minimization. For this target we suggest a multi-objective problem that is controlled by compensation factor. This strategy is very useful for both maximum throughput applications and power saving one that is because the objective of these two strategies are taken in utility function through compensation factor. Two techniques have been combined for optimization for subcarrier allocation. The first efficiently chooses subcarrier allocation providing subgroups of tones for users. A second objective maximizes the rate which allocated per each subcarrier. A genetic algorithm (GA) is used to optimize a Pareto surface of power allocation and continuous rate. Through the simulated results we have rate between 6 to 8 bit/sec/Hz according to compensation factor, channel environment and power constraint