Random subcarrier allocation with supermodular game in cognitive heterogeneous networks

Cognitive heterogeneous networks (HetNets) have been recently introduced as a promising solution to meet the user demand for higher data rate. Due to the physical coexistence of microcells, femtocells and the lack of available spectrum, there is a need for techniques that allows users to share the same spectrum while maintaining required performance level for each user by adopting interference mitigation techniques. In this paper, we focus on resource allocation algorithm for orthogonal frequency-division multiple access (OFDMA) cognitive networks using game theory. In particular, we consider supermodular game theory, where given the problem meets specific requirement, the game has two significant features; it has at least one pure Nash Equilibrium (NE) and its best responses are monotonically increasing. Our objective is that each femtocell user selects a specific number of subcarriers determined by its needs. In comparison where at each iteration of the game, the femtocell user search all the subcarriers to maximize its payoff, our algorithm is based on selecting the subcarriers randomly and checks only those subcarriers that achieve higher payoff. Our results show that our algorithm reaches NE and can provide lower feedback compared to the sweeping-all subcarriers.