Patent ID: 11889372
Assignee: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method of operation of a wireless communication device to perform handover from a source cell to a target cell in a wireless communication system, comprising:
performing a beam tracking procedure for one or more neighbor cells to provide, for each neighbor cell, a list of tracked beams for the neighbor cell;
receiving a handover command from a source radio access node that instructs the wireless communication device to perform a handover from a source cell served by the source radio access node to a target cell served by a target radio access node, wherein the target cell is one of the one or more neighbor cells for which the beam tracking procedure is performed;
selecting a beam of the target cell from the list of tracked beams for the target cell based on random access resource configuration and/or a quality threshold; and
performing random access on the selected beam;, wherein selecting the beam of the target cell from the list of tracked beams for the target cell comprises:
determining that there are no dedicated random access channel resources allocated for contention-free random access for the best beam in the list of tracked beams for the target cell; and
upon determining that there are no dedicated random access channel resources allocated for contention-free random access for the best beam in the list of tracked beams for the target cell:
determining a difference between a quality of the best beam in the list of tracked beams for the target cell and a quality of a k-th best beam in the list of tracked beams for the target cell, the k-th best beam being a beam for which dedicated random access channel resources are allocated; and
determining whether the difference is less than a threshold, where the selected beam of the target cell is the k-th best beam if the difference is less than the threshold.