QoS optimization for multimedia transmission over cognitive radio networks using multicarrier modulation

Cognitive radio (CR), has recently emerged as a promising technology to enhance the spectrum utilization while providing a height Quality of Service (QoS) for users. One of the basic features of cognitive radio is the ability to adapt to a changing RF environment. The adaptation for a cognitive radio means finding the best transmissions parameters that enable the secondary users to communicate with a certain QoS taking in consideration their environment and the priority of the user´ needs. The optimization of the radio resource allocation among users has been previously studied using genetic algorithms (GA) by scoring a subset of objectives. In this paper, we exploit the firefly algorithm (FF) proposed in 2008 to optimize the communication quality of secondary users in a multicarrier multimedia application. The fitness function has been formulated as a multi-objective problem and in the context of multimedia transmission investigated herein; the highest weighting has been given to the data throughput. The other investigated objectives in this problem were the minimization of bit error rate and the minimization of power consummation. According to our best knowledge, this approach has not been yet presented neither for the general CR case nor for the multicarrier CR case. The performance of our algorithm is compared to the GA in the figure below in terms of the best fitness value, where it can be seen that the convergence rate and the value of the fitness function have been improved, which is viable in multimedia applications.