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English (United Kingdom)

Adaptive beam-centric admission control for WCDMA multicell/multiservice scenarios with non-uniform traffic

Year: 2009
Type of Publication: Article
Journal: Journal of Wireless Personal Communications Volume: 58
Pages: 369-389
The goal of the study presented in this paper is the accurate performance evaluation of adaptive beam-centric admission control (AC) for wideband code-division multiple access (WCDMA) multicell networks with non-uniform traffic requirements. Each NodeB employs antenna arrays (AAs), used either to form fixed grids of beams (FGoBs), or to steer and shape multiple beams towards directions of increased traffic, in an adaptive manner. The adaptive beam-centric AC maximizes the cell throughput in a multirate/multicell environment by grouping as many users as possible under a common beam formed by the AA, taking into account their spatial distribution and overall interference. Due to the increased complexity of the Monte Carlo (MC) simulations, a novel grid-enabled problem solving environment has been developed in order to reduce execution times considerably and make feasible full scale extensive simulations of complex operational scenarios (up to 4 tiers of cells, multiple beams per cell, non-uniform traffic distributions with different spatial characteristics). Results show that the network with the adaptive beam-centric AC can achieve significantly higher throughput per beam in multirate/multicell environments with hotspots. In particular, it is shown that the throughput per beam gain depends exponentially on the number of hotspots per cell and their angular width, and gains up to 200/350/700% can be achieved with 1/2/3 hotspots, respectively. Moreover, it is shown that the adaptive beamcentric AC provides significant reduction in interbeam handovers, which leads to more available resources in downlink, reduced signaling requirements and easier network planning.