Patent ID: 7333441

Claim:
A method for controlling packet switched data traffic in digital cellular communication systems, in which a cell reselection is forced, said cell reselection being controlled by network control units of mobile stations engaged in packet switched calls and identified in a search step in which the control units evaluate path loss levels of signals relevant to communication of the mobile stations engaged in these calls with both a base station of a respective serving cell and base stations of a plurality of cells contiguous to a serving cell, said method comprising the steps of: a) jointly determining, for each one of the mobile stations in a involved cell, at least a first and a second parameter related to path loss for both communication with the base station of the serving cell and communication with the base stations of said plurality of contiguous cells; b) including mobile stations for which both of said parameters indicate a degradation of communication with the base station of the serving cell and a good quality of communication with a base station of at least a contiguous cell, into a list candidates mobile stations to receive a reselection command from said control units; c) associating, with each candidate station in said list, an identity of one or more contiguous cells identified as possible target cell or cells for the station in step b); and d) forcing a reselection of a candidate mobile station towards one of the contiguous cells which supports packet switched service and has an occupation level of radio resources involved in packet switched traffic not higher than a first threshold, set by a network operator and typical of the cell; wherein the search is enabled in a cell by either: reaching or exceeding in the cell a second threshold, higher than the first threshold of occupation of radio resources invoked in packet switched traffic, the second threshold being set by the network operator and being specific for each cell; or a specific request to release a given mount of radio resources, supplied by a radio resources control unit and due to quality-of-service requirements, for a cell candidate to accept a mobile station that shall establish a new packet switched call.