Method and arrangement for saving radio resources

摘要

The present invention relates to an arrangement, a communication network node and a method of saving radio resources during handover in a communication network system comprising a plurality of communication network nodes (15a, 15b, 15c) communicating with one or more user equipments (18). Each network node (15a, 15b, 15c) is serving at least one cell (19) through and in which the user equipments (18) are moving. The method and arrangement is based on: collection of long term handover statistics (1); selective triggering of Multiple Cell Preparation (2); definition of a Secondary Target Cell List (3); exclusion from the Secondary Target Cell List of cells rarely used (4); preparation of the cells on the Secondary Target Cell List for handover (5).

主权项

1. A method of saving radio resources during handover of a user equipment between cells in a communication network system, wherein each cell is served by a respective communication network node, wherein said handover is made from a source cell to one of a plurality of target cells included in a neighbor cell list, and wherein the method comprises:
collecting long term handover statistics describing past handovers to one or more target cells included in the neighbor cell list; checking if a triggering condition is fulfilled for selectively triggering multiple target cells to prepare for the handoff; if the triggering condition is not fulfilled, preparing one primary target cell included in the neighbor cell list for the handover; and if the triggering condition is fulfilled:
defining, based on the long term handover statistics, a secondary target cell list that includes one or more secondary target cells to be prepared for the handoff, in case handoff to the primary target cell fails, adding a secondary target cell to the secondary target cell list if a cell addition condition is fulfilled and excluding a secondary target cell from the secondary target cell list if a cell exclusion condition is fulfilled, to thereby exclude secondary target cells that, as indicated by the long term handover statistics, are rarely used for handoff; andpreparing the secondary target cells included in the secondary target cell list for the handover by sending handover request messages to those secondary target cells.