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Abstract-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 may heavily overlap. The paper examines the benefit of coordinating transmission strategies and resource allocation schemes across multiple cells for interference mitigation. For a multicell network serving multiple users per cell sectors and where both the base-stations and the remote users are equipped with multiple antennas, this paper proposes a joint proportionally fair scheduling, spatial multiplexing, and power spectrum adaptation method 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 system is shown to significantly improve the overall network throughput while maintaining fairness as compared to a conventional network with per-cell zero-forcing beamforming and with fixed transmit power spectrum. The proposed system 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 basestations as a first step. I. OVERVIEW A. IntroductionIntercell interference is a fundamental limiting factor in wireless cellular networks. A promising idea for the mitigation of intercell interference in future cellular networks is the coordination of multiple base-stations. In a fully coordinated multicell system, multiple antennas across multiple basestations can be thought of as forming a large antenna array, where intercell interference can be actively exploited. The realization of such a fully coordinated system, however, also requires high-capacity backhaul communication. As antennas from across multiple base-stations need to jointly transmit and receive signals for multiple mobile users, data streams of multiple users must be shared among multiple base-stations. This paper explores a different type of coordination where user transmission strategies and resource allocation schemes, rather than data signals, are coordinated across the basestations. The coordination of transmission strategies clearly requires much less backhaul communication, and is much easier to implement in a practical deployment. The goal of this paper is to show that by jointly setting the scheduling, power allocation, and beamforming strategies of multiple basestations and multiple mobile users within each cell, intercell interference can already be alleviated, and the overall performance of the network can already be improved significantly as compared to the current generation of wireless networks where cells operate independently.Resource management has been the focus of extensive studies for cellular networks in the past, but tr...

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An electrically tunable photonic crystal is developed utilizing crystalline colloidal arrays of high refractive index particles. Through modulation of the refractive index of the particle, and the applied electric field, both the bandwidth and position of the photonic bandgap could be tuned. Full color modulation with high optical quality is achieved, which paves a way to develop a novel reflective display.