Power spectrum optimization for interference mitigation via iterative function evaluation

This paper proposes practical methods for and examines the benefit of dynamic power spectrum optimization for interference mitigation in wireless networks. The paper envisions a distributed antenna system, deployed as a means to increase the network capacity for areas with high data traffic demand. The network comprises several access nodes (AN), each serving a fixed set of remote radio units called remote terminals (RT). The RTs belonging to each AN are separated from each other using orthogonal frequency division multiple access (OFDMA) over a fixed bandwidth, where only one RT is active at each frequency tone. The system performance is thus limited by internode interference solely, and no intranode interference. This paper proposes methods for power spectrum optimization based on the idea of iterative function evaluation. The proposed methods provide a significant improvement of the overall network throughput, as compared to conventional wireless networks with fixed transmit power spectrum. The proposed methods are computationally feasible and fast in convergence. They can be implemented in a distributed fashion across all access nodes, with reasonable amount of internode information exchange. Some of the proposed methods can be further implemented asynchronously at each AN, which makes them amenable to practical utilization.