Power allocation schemes for relay-based heterogeneous networks

We consider an interference limited heterogeneous cellular network, where co-channel macro and femto cells coexist. We focus on the downlink transmission, where a macro base station (MBS) communicates with a macro user equipment (MUE) via a macro relay station (MRS), whereas femto base stations (FBS) communicate with femto user equipments (FUE) directly. We propose centralized power allocation schemes to optimally allocate power among the MBS, MRS and FBSs. The power allocation schemes consider the difference in the significance of macro and femto networks by assigning different importance levels. Then, we discuss a distributed approach, where each cell can independently and separately optimize its own downlink transmission power. Numerical results indicate the effectiveness and performance of our schemes.