Patent ID: 8849263
Filing Date: 2014-09-30
Classification: H04W

Abstract:
1. A method for performing handover carried out by a terminal in a radio access system, wherein multiple femto base stations including a serving femto base station form a single group, the method comprising: transmitting a request message for requesting a seamless handover within the formed group to the serving femto base station; receiving a first command message from the serving femto base station, the first command message including transmission power information and dedicated uplink resource allocation information being commonly applied to the formed group; broadcasting a predetermined uplink signal, wherein transmission power indicated by the transmission power information through an uplink resource, which is indicated by the dedicated uplink resource allocation information, is applied to the predetermined uplink signal; receiving a second command message from the serving femto base station, the second command message including measurement results of the uplink signal measured by each of at least one femto base station included in the group; and performing network re-entry to a target base station among the at least one femto base station, wherein the multiple femto base stations included in the group correspond to Closed Subscriber Group (CSG) femto base stations or correspond to femto base stations belonging to the same Open Subscriber Group (OSG), and wherein the multiple femto base stations share context of the terminal, wherein the performing the network re-entry comprises: wherein the ranging response message includes a handover (HO) optimization field, the HO optimization field being set up to have a value indicating a process step that can be omitted from performing the network re-entry due to the sharing of the context of the terminal.