Group handover scheme using adjusted delay for multi-access networks

In this paper, we propose a group handover scheme in multi-access networks, which utilizes adjusted delay to prevent handover blockings caused by a group handover. In the group handover, a lot of users try to initiate a handover at the same time, which causes network congestion and increases the probability that the handover would be blocked. In our proposed scheme, to prevent these problems of a group handover, each user which participates in the group handover, optimally selects an access point(AP) based on the remaining resources of the AP, and each user initiates a handover after adjusted delay to prevent network congestion. To find an optimal AP selection strategy, we formulate an optimization problem whose objective is to minimize handover blocking probability, and derive an optimal solution by using the Karush-Kuhn-Tucker (KKT) condition. Through performance analysis and simulation results, we show that our proposed scheme can reduce handover blocking probability in a group handover compared to a conventional scheme and keep handover blocking probability to be less than the maximum allowable value of handover blocking probability.