A GA-Based Optimization for Frequency-Selective Scheduling in Downlink OFDMA Systems With Cyclic-Delay Diversity
CDD (Cyclic-Delay Diversity) aided frequency-selective scheduling has been known as an effective technique to increase system capacity of the OFDMA (Orthogonal Frequency-Division Multiple Access) systems. By increasing the channels' frequency selectivity with cyclic delays, the merit of multi-user diversity can be exploited more effectively in the system. In this paper, the authors aim to optimize the design of the CDD-aided frequency-selective scheduling for downlink OFDMA systems. A Genetic Algorithm (GA)-based optimization is devised to obtain the cyclic-delay values which provides a higher system sum-rate than the multi-degree adaptive cyclic-delay diversity method and has a lower computational complexity than the exhaustive method with only a slight degradation in system sum-rate.