Weighted Bandwidth–Power Product Optimization in Downlink Femtocell Networks

In order to develop a completely distributed resource allocation scheme to improve data rates and mitigate mutual interference across orthogonal frequency-division multiple access (OFDMA)-based femtocell networks, a space–bandwidth product (SBP) has been proposed as an effective measurement of network coverage. Intuitively, a femtocell minimizing its SBP tends to utilize subchannels experiencing less interference and will thus minimize its interference on other femtocells, which represents good self-organizing performance and enables a completely distributed resource allocation algorithm. However, for an OFDMA-based femtocell, most existing studies have applied the same weights on the bandwidth and the power without distinguishing the different significance on them. In this letter, we first formulate a weighted bandwidth–power product minimization problem for an OFDMA-based femtocell, applying different emphases on the consumed bandwidth and power while satisfying all users´ data rate requirements. Then, in this direction, we further reformulate and iteratively solve this nonconvex problem via the Successive Convex Approximation for Low-complExity (SCALE) approach. Simulation results show that our proposed algorithm converges to stable solutions in a finite number of iterations.