Energy efficiency design in MC-CDMA cooperative networks

Abstract

The energy efficiency (EE) maximization in multi-carrier code division multiple access (MC-CDMA)1 cooperative wireless networks is a NP-hard optimization problem of great interest for future networks systems as well as wireless sensor networks. This paper presents a game theoretic approach for EE maximization in MC-CDMA wireless cooperative networks considering receiver single-user or multi-user design, as well as distributed implementation approach in order to solve the EE design problem. Moreover, the iterative water-filling algorithm (IWFA) and the Verhulst distributed power control algorithm (V-DPCA) are employed to solve the inner loop of the proposed EE maximization algorithm. A study over the quasi-concavity of the utility function is presented while numerical results are offered to corroborate the mathematical model, as well as to verify the better performance of the IWFA over the V-DPCA. Indeed, the superiority of the IWFA over V-DPCA in terms of both EE and SE is evident. This may be explained through the fact that the IWFA optimizes the power allocation of each user through all sub-carriers at the same time, while Verhulst-based DPCA performs the power control on each sub-channel considering all users.