Energy-Efficient Opportunistic Interference Alignment

We introduce an energy-efficient distributed opportunistic interference alignment (OIA) scheme that greatly improves the sum-rates in multiple-cell uplink networks while reducing the transmit power consumption compared to the conventional OIA scheme. In the proposed scheme, each user employs optimal transmit vector design and power control strategy in the sense of minimizing the amount of generated interference to other-cell base stations while satisfying a given required signal quality. Our main result indicates that owing to the reduced interference level, the proposed OIA method attains larger sum-rates than those of OIA with no power control (i.e., with full transmit power) for almost all signal-to-noise ratio regions, thus resulting in improved energy efficiency.