Coordinated Scheduling, Beamforming and Power Spectrum Adaptation in Wireless Cellular Networks

The mitigation of intercell interference is a central issue for future-generation wireless cellular networks where frequencies are reused aggressively and where hierarchical cellular structures heavily overlap. The paper examines the benefit of coordinating transmission strategies and resource allocation schemes across multiple access-points for interference mitigation. Two different wireless cellular architectures are studied: a multicell system where base-stations cooperate in their transmission strategies, and a mixed macrocell and femtocell/picocell deployment where macro and femto/pico basestations cooperate. For both scenarios, this paper proposes a joint proportionally fair scheduling, spatial multiplexing, and power spectrum adaptation algorithm that coordinates multiple basestations with an objective of optimizing the overall network utility. The proposed scheme optimizes the user schedule, transmit and receive beamforming vectors, and transmit power spectra jointly, while taking into consideration both the intercell and intracell interference and the fairness among the users. The proposed approach is shown to significantly improve the overall network throughput while maintaining fairness as compared to a conventional network design with fixed transmit power and percell zero-forcing beamforming. It goes toward the vision of a fully coordinated multicell network, whereby transmission strategies and resource allocation schemes (rather than transmit signals) are coordinated across the base-stations as a first step. EDICS: WIN-SYLO, WIN-RSMG