Spectral and energy efficiency tradeoff in optical code division multiple access networks

A paradigm on the energy efficiency (EE) and spectral efficiency (SE) tradeoff named resource efficiency (RE) exploits the EE-SE equilibrium, which is formulated as Pareto optimal set based on two objectives balancing power consumption against occupied bandwidth. In optical code division multiple access (OCDMA) networks, the EE-SE tradeoff is discussed by formulating a multiobjective optimization problem, while solutions are compared by deploying the weighted sum (WS) and epsilon-Constraint (epsilon-C) scalarization procedures combined with nonlinear programming methods. The generalized RE optimization problem with QoS guarantees for the OCDMA networks is formulated considering that such methods result in the same Pareto boundaries. Theoretical results demonstrate that the obtained numerical optimized solutions are efficient due to the multiobjective characteristics of the optimization problem. Also, considering the numerical tests performed, it is noteworthy that the epsilon-C procedure found a greater diversity of solutions inside the Pareto front when compared with the WS method.