Patent ID: 9094910
Filing Date: 2015-07-28
Classification: H04W

Abstract:
1. A method utilized in a mobile device, the method comprising: starting a time alignment timer when receiving a time alignment message transmitted by a base station, wherein the time alignment timer is used for determining whether the mobile device is synchronized with the base station on uplink timing, and the time alignment message is utilized to update timing advance for the mobile device; ignoring at least a first control message, which comprises a downlink grant and at least one associated data message or comprises an uplink grant, sent from the base station by a communication unit and transmitted via a physical downlink control channel (PDCCH), by discarding the first control message after the time alignment timer expires without receiving the at least one associated data message or without transmitting data to the base station according to the uplink grant; and starting a random access procedure for obtaining uplink synchronization by transmitting a random access preamble to the base station, once a buffer status report is triggered to update a buffer status of the mobile device for the base station for precise uplink scheduling after the time alignment timer has expired or once the mobile device receives a second control message via the PDCCH comprising downlink data arrival information sent by the base station after the time alignment timer has expired.