Resource Allocation for SC-FDMA Femtocell Networks

Abstract

We consider joint subcarrier and power allocation problem for uplink femtocell networks. The air interface is single carrier frequency division multiple access. We consider zero forcing and minimum mean square error frequency domain equalizers. To formulate the resource allocation problem, we derive a closed-form expression for the received signal-to-interference-plus-noise ratio. Since the cross-tier interference can deteriorate the macrocell data rate, we impose a temperature limit on the interference arising from femtousers to the macro-base station. This constraint protects the data rate of the macrousers. Moreover, we consider the quality of service requirement constraint for the high data rate femtousers, and the adjacency of the assigned subcarriers to a user. We divide the optimization procedure into two steps: the power allocation and the subcarrier assignment. In the first step, we use the dual problem to obtain the optimal powers. In the second step, we formulate the problem of subcarrier allocation as binary integer programming (BIP). The BIP problem is NP-hard and cannot be solved in polynomial time. To reduce the complexity, we propose a practical suboptimal algorithm for the subcarrier assignment, which is significantly simpler than the BIP approach.