Power allocation scheme for mitigation of fiber temperature fluctuations in OCDMA networks based on firefly algorithm

In this paper, a power allocation scheme based on an evolutionary heuristic approach, namely Firefly Algorithm (FA) is proposed for the mitigation of fiber temperature fluctuations effects in the optical code division multiplexing access (OCDMA) networks. The temperature fluctuations degrade the 2-D wavelength-hopping time spreading optical codes by inducing a distortion on the autocorrelation of the received signal. The fiber temperature fluctuations are ordinarily hard to accurately determine and compensate due to the dynamic nature of the environmental temperature variation. In this context, power allocation (PA) policies constitute an efficient way to dynamically mitigate the effects of temperature variation with low cost and complexity of implementation. In this work, an FA input parameter optimization procedure has been conducted aiming to guarantee an efficient FA-based OCDMA power allocation algorithm regarding convergence velocity and quality of the solutions trade-off. The numerical results have demonstrated the effectiveness of the proposed FA power allocation scheme in mitigating the effects of fiber temperature fluctuations, as well as balancing the near-far effect (NFE) and multiple access interference (MAI). Moreover, the influence of the code parameters and the number of the nodes on the FA-based OCDMA power allocation scheme has been investigated. The comparison from both evolutionary heuristics FA and particle swarm optimization (PSO) power allocation schemes has indicated the faster convergence of FA-based scheme when the number of nodes K increases, while for both the complexity is similar, resulting in polynomial order O(K2). Moreover, the FA-based power allocation approach presents a smoother and monotonic convergence when compared with the more oscillatory behavior of the PSO-based power allocation procedure.