Energy efficient resource allocation in OFDMA networks using ant-colony optimization

A novel technique for jointly allocating sub-carriers, modulation and coding scheme (MCS) and transmit power in an orthogonal frequency division multiple access (OFDMA) cellular network using ant-colony optimization technique is proposed. Different combinations of user indices, MCS indices and subcarrier indices form the nodes in the graph. Each possible assignment of the above resources is a path in the graph. Resource allocation is carried out by mimicking the behavior of ants, that the ants are likely to choose the path identified as a shortest path, which is indicated by a relatively higher density of pheromone left on the path compared to other possible paths. Likewise, the combination of resource allocation that satisfies the requested data rate with least energy consumption is preferentially allocated and therefore attains a high `pheromone´ level. As such, the aforesaid allocation is preferentially selected by an evolved nodeB (eNB). Also, the simulation results show 6 and 1.4 times increase in throughput, 15% increase in satisfied users and 17% decrease in transmit power when the proposed approach is compared against full chunk reuse system with link adaptation, chosen as a benchmark.