Distributed Power Allocations in Heterogeneous Networks with Dual Connectivity using Backhaul State Information

LTE release 12 proposes the use of dual connectivity in heterogeneous cellular networks, where a user equipment (UE) maintains parallel connections to a macro-cell node (base station) and to a low-tier node (pico base station or relay). In this paper, we propose a distributed multi-objective power control scheme where each UE independently adapts its transmit power on its dual connections, possibly of unequal bandwidth, with non-ideal backhaul links. In the proposed scheme, the UEs can dynamically switch their objectives between data rate maximization and transmit power minimization as the backhaul load varies. Given the coupling between interference and the backhaul load, we propose a low-overhead convergence mechanism which does not require explicit coordination between autonomous nodes and also derive a closed-form expression of the transmit power levels at equilibrium. We illustrate a higher aggregate end-to-end data rate and significant power saving for our scheme over when the optimization is implemented through a greedy algorithm or when UEs only perform waterfilling.