Cross-scheduling for random access response

摘要

In a random access procedure, a downlink random access response indicates at least a timing advance and an explicit indication identifying one component carrier or cell (CC/Cell) of a plurality of component carriers or cells, or a group of CCs/Cells, to which the timing advance applies. The eNB or UE then operate their radio on the indicated one CC/Cell synchronous with the timing advance. In various embodiments the random access response may also indicate an uplink resource granted to the user equipment, which lies on that same one or group of CCs/Cells. The explicit indication may be a single bit indicating a timing advance group; a CC/Cell/group index whose presence in the response is indicated by a flag bit; a CC/Cell/group index in the response is known from the response's format whether it includes such an index, where the format indication can be via a bit in the response itself or RRC signaling or implicit from the RACH and cross-carrier scheduling being configured.

主权项

1. An apparatus, comprising:
at least one processor; and at least one memory including computer program code; in which the at least one memory and the computer program code are configured with the at least one processor to cause the apparatus at least to:
perform a random access procedure in carrier aggregation in which, upon reception of a transmission of a previously assigned preamble on one secondary cell of a plurality of component carriers or cells, a downlink random access response is sent and scheduled by a control channel addressed to a random access identifier on a primary component carrier or primary cell of a plurality of component carriers or cells;the random access response indicating a timing advance and identifying a group of component carriers or cells, to which the timing advance applies to all component carriers or cells within the group; and thereafteroperate a wireless radio on the identified group of component carriers or cells synchronous with the timing advance.