Uplink transmission method and apparatus in carrier aggregation system

摘要

The invention discloses an uplink transmission method and apparatus in a carrier aggregation system and relates to the field of radio communications so as to address the issue of how to perform uplink transmission in a secondary cell when a base station configures a user equipment additionally with the secondary cell. In the invention, a user equipment selects, under a preset reference carrier selection rule, one of downlink carriers corresponding to cells having already established downlink synchronization with a base station as a timing reference downlink carrier used by a secondary cell after the base station configures the user equipment additionally with the secondary cell; and the user equipment performs uplink transmission in the secondary cell according to downlink timing of the timing reference downlink carrier. With the invention, a timing reference downlink carrier used by an additionally configured secondary cell in uplink transmission can be determined and uplink transmission can be further preformed over the timing reference downlink carrier.

主权项

1. An uplink transmission method in a carrier aggregation system, comprising:
a user equipment selecting, under a preset reference carrier selection rule, one of downlink carriers corresponding to cells having already established downlink synchronization with a base station as a timing reference downlink carrier used by a secondary cell, after the base station configures the user equipment additionally with the secondary cell; and the user equipment performing uplink transmission in the secondary cell according to downlink timing of the timing reference downlink carriers; wherein, the selecting, under a preset reference carrier selection rule, one of downlink carriers corresponding to cells having already established downlink synchronization with a base station as a timing reference downlink carrier used by a secondary cell comprises: a user equipment selecting a timing reference downlink carrier used by a cell which is in a Timing Advance (TA) group to which the secondary cell belongs and has already established uplink synchronization with the base station as a timing reference downlink carrier used by the secondary cell; or the user equipment selecting a downlink component carrier corresponding to a cell the last to initiate a random access successfully in a TA group to which the secondary cell belongs as a timing reference downlink carrier used by the secondary cell; or the user equipment selecting a downlink component carrier corresponding to an active cell with the lowest number in a TA group to which the secondary cell belongs as a timing reference downlink carrier used by the secondary cell; or the user equipment selecting a downlink carrier corresponding to a primary cell as a timing reference downlink carrier used by the secondary cell; or the user equipment selecting a downlink carrier corresponding to the secondary cell as a timing reference downlink carrier used by the secondary cell; or the user equipment selecting a downlink carrier corresponding to a cell which is beyond a TA group to which the secondary cell belongs and has already established uplink synchronization with the base station as a timing reference downlink carrier used by the secondary cell; or the user equipment selecting a downlink carrier corresponding to a cell preconfigured by the base station as a timing reference downlink carrier used by the secondary cell.