Optimal power allocation for sum capacity of a slotted three-cell system

Substantial gains are realizable through basestation cooperation during assignment of transmission powers to users. While binary power assignment is optimal for sum capacity in a two-cell system, it does not hold true in general for multi-cell systems. In this paper, we study an optimal power allocation for sum capacity in a three-cell system. The proposed branching algorithm is of linear computational complexity, and provides a power assignment which achieves a sum capacity arbitrarily close to the theoretical value. This result provides the impetus for next generation wireless systems to enable basestations to perform joint power assignment across multiple cells.