Beamwidth Scaling in Wireless Networks with Outage Constraints

Trung-Anh DO  Won-Yong SHIN  

IEICE TRANSACTIONS on Communications   Vol.E98-B   No.11   pp.2202-2211
Publication Date: 2015/11/01
Online ISSN: 1745-1345
Type of Manuscript: PAPER
Category: Fundamental Theories for Communications
beamwidth scaling,  directional antenna,  outage constraint,  scaling law,  transmission capacity,  wireless network,  

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This paper analyzes the impact of directional antennas in improving the transmission capacity, defined as the maximum allowable spatial node density of successful transmissions multiplied by their data rate with a given outage constraint, in wireless networks. We consider the case where the gain Gm for the mainlobe of beamwidth can scale at an arbitrarily large rate. Under the beamwidth scaling model, the transmission capacity is analyzed for all path-loss attenuation regimes for the following two network configurations. In dense networks, in which the spatial node density increases with the antenna gain Gm, the transmission capacity scales as Gm4/α, where α denotes the path-loss exponent. On the other hand, in extended networks of fixed node density, the transmission capacity scales logarithmically in Gm. For comparison, we also show an ideal antenna model where there is no sidelobe beam. In addition, computer simulations are performed, which show trends consistent with our analytical behaviors. Our analysis sheds light on a new understanding of the fundamental limit of outage-constrained ad hoc networks operating in the directional mode.