Ant colony optimization based dynamic subcarrier, bit and power allocation for OFDMA-based relay networks

Abstract

Due to the performance improvement by flexible resource allocation approaches, the employment of Relay Stations (RSs) and the Orthogonal Frequency Division Multiple Access (OFDMA) have been extensively considered as a capable technique for future cellular infrastructure. The downlink of a cell is taken into consideration in an OFDMA based relay network. In the cell, a Base Station (BS) and fixed Relay Stations (RSs) are deployed. Multiple Subscriber Stations (SS) are positioned in the cell. A SS is served either by a direct or a two hop connection. A connection between BS and SS is present in a direct connection. In a two hop connection, a connection exists between BS and RS and between RS and SS. An approach for resource allocation is presented which dynamically assigns subcarriers, bits and power to the existing links depending on instant channel state information. This paper focuses on minimizing the power required for the transmissions of the BS and the RSs through an efficient optimization technique. Ant Colony Optimization (ACO) technique is formulated for providing the optimized results. The performance evaluation of the proposed ACO based resource allocation technique suggests that the essential power required is lower than the power required by other existing resource allocation techniques in a defined scenario of a relay network.