On the Effect of User Mobility in Mobile Radio Systems With Distributed DCA

In this paper, the impact of user mobility and the handover process on the performance of interference adaptive (IA) dynamic channel allocation (DCA) schemes is investigated. Among the hundreds of papers that can be found in the literature dealing with DCA (IEEE Pers. Commun., vol. 3, no. 3, p. 10, Jun. 1996), only very few analyze their performance by taking into proper consideration all the aspects related to user mobility: the speed of mobiles, the handover process, the radio channel fluctuations, and the forced terminations. The results we show in this paper have been achieved by means of a simulation tool that takes propagation, mobility, handover, power control, directed retry (DR), interference, traffic, and channel allocation into account. Moreover, some simplified analytical descriptions are given to discuss the behavior of the blocking probability when varying the speed of users. We compare the performance of well-known totally distributed IA-DCA schemes (least interference algorithm and least interference and threshold algorithm) (IEEE J. Sel. Areas Commun., vol. 14, no. 5, p. 698, May 1996) to that of a partially distributed algorithm. The comparison to fixed channel allocation is also considered, and the role of DR is emphasized. To emphasize the role played by the speed of the terminals, two different mobility models are considered; the numerical results show that the satisfaction probability changes when taking user mobility into account, whereas the blocking probability is scarcely affected by the mobile speed; the latter statement is compared to previous results from the literature, and it is in good agreement.