Small cell networks are regarded as a promising candidate to meet theexponential growth of mobile data traffic in cellular networks. With a densedeployment of access points, spatial reuse will be improved, and uniformcoverage can be provided. However, such performance gains cannot be achievedwithout effective intercell interference management. In this paper, a novelinterference coordination strategy, called user-centric intercell interferencenulling, is proposed for small cell networks. A main merit of the proposedstrategy is its ability to effectively identify and mitigate the dominantinterference for each user. Different from existing works, each user selectsthe coordinating base stations (BSs) based on the relative distance between thehome BS and the interfering BSs, called the interference nulling (IN) range,and thus interference nulling adapts to each user's own interference situation.By adopting a random spatial network model, we derive an approximate expressionof the successful transmission probability to the typical user, which is thenused to determine the optimal IN range. Simulation results shall confirm thetightness of the approximation, and demonstrate significant performance gains(about 35%-40%) of the proposed coordination strategy, compared with thenon-coordination case. Moreover, it is shown that the proposed strategyoutperforms other interference nulling methods. Finally, the effect ofimperfect channel state information (CSI) is investigated, where CSI is assumedto be obtained via limited feedback. It is shown that the proposed coordinationstrategy still provides significant performance gains even with a moderatenumber of feedback bits.
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