Subcarrier-And-Bit Allocation in Multiclass Multiuser Single-Cell OFDMA Systems Using an Ant Colony Optimization Based Evolutionary Algorithm

In this paper, for the first time, an Ant Colony Optimization (ACO) based algorithm is used to solve the bit and subcarrier resource allocation problem of single-cell OFDMA systems. It results in a directed multigraph if the vertexes are used to represent the subcarrier and each path corresponds to a possible chosen modulation index of a specific user. Earlier studies which applied evolutionary algorithms (EAs) focused on single-class service, with no guarantee on individual QoS requirement in terms of bit rate and bit-error-rate performance. The proposed ACO guarantees the required minimum bit rate for all users while minimizes the total power consumption at the base station (BS). Simulation results show that comparing to other classes of EAs such as the Genetic algorithm, and the extended version of water-filling algorithm to support QoS traffic, ACO can obtain better solutions more often. We also observe that the performance is significantly better when the minimum demand bit rates for users are higher. Comparing to earlier developed GA, our proposed ACO algorithm also converges much faster but it needs more memory space to implement the ACO algorithm.