Patent ID: 9144000
Filing Date: 2015-09-22
Classification: H04W

Abstract:
1. A cell specifying method in a cellular mobile communication system which includes a mobile station and base stations forming cells, and which operates in a first state in which the mobile station has not established a connection with a base station and in a second state in which the connection has been established with any of the base stations, the method comprising: storing, by the mobile station, cell selection history including one or more selection histories of the cells performed in accordance with first criteria for cell reselection in the first state and a serving time of the mobile station in the cell in the first state in time order; transmitting, by the mobile station, the cell selection history to a base station of a second cell when performing a handover from a first cell to the second cell in accordance with second criteria for handover in the second state; referring, by the base station of the second cell, to the transmitted cell selection history, and specifying a cell in which the first criteria and the second criteria are not aligned from among the first cell and the second cell based on the cell selection history, when it is determined that the mobile station has performed the handover from the first cell to the second cell in a predetermined period after a transition from the first state to the second state; and specifying, by the base station of the second cell, which one of the first cell and the second cell is said non-aligned cell, where the base station of the second cell specifies that said non-aligned cell is the first cell but not the second cell when determined that a first selection history just before the handover indicates that the serving time in the first cell in the first state is equal to or larger than a threshold value, based on the cell selection history, and where the base station of the second cell specifies that the non-aligned cell is the second cell but not the first cell when determined that the first selection history indicates that the serving time in the first cell in the first state is smaller than the threshold value and further a second selection history just before said first selection history indicates that the serving time in the second cell in the first state is equal to or larger than the threshold value, based on the cell selection history.