A multicell model of handover initiation in mobile cellular networks

In this paper, a model is provided for the analysis of handover initiation algorithms in cellular systems, which are based on the averages of signal s trength measurements and hysteresis. An extension of Vijayan's and Holtzman 's model is achieved, which accounts for: 1) the effects of the angular dir ection when a mobile terminal moves from a current to a target base station ; 2) the presence of more than two base stations; and 3) the effects of cro ss correlation of shadow fadings affecting the links between the mobile ter minal and the various base stations. The level crossing theory of Gaussian processes is used to derive algorithm performance. The results obtained fro m the model are in good agreement with those obtained from simulations. It is seen that the model tends to underestimate algorithm performance, thus y ielding a lower performance bound and guaranteeing an intrinsic design marg in. It is also seen that, for a typical trajectory of the mobile terminal f rom the current base station, the number of handovers might be noticeably i ncreased due to the presence of disturbant stations. Moreover, when cross c orrelation among shadow fadings is also accounted for, significant variatio ns are observed in both the number of handovers and handover delay. As a fi nal result, tradeoff curves are derived and presented for the most general case.