| abstract |
For accomplishing an interference-free handover in a cellular communication system which has at least one base station per cell, which base station is controlled by a base station controller which controls one or more base stations, and which base station controller, with the base station or stations under its control, forms a base station system, the respective service areas of respective base stations under different base station controllers at the border or borders of two or more base station systems are caused to at least partly overlap. As a terminal equipment moves from one base station system to another, handover of the terminal equipment from one base station to another is carried out so that as the terminal equipment moves into a cell served by all of two or more base stations which belong to areas of different base station controllers, the terminal equipment carries out a soft handover from an existing base station to a new base station, and, as it further moves towards a respective cell border, it carries out a hard handover from the previously serving base station the previously serving base station system to a respective base station of the newly serving base station system, the service area of which at least partly overlaps with that of the previously serving base station. |