Patent ID: 8542654

Claim:
A method comprising: a) transmitting, by a base station, at least one control message to a wireless device in a plurality of wireless devices, said at least one control message: i) configured to cause in said wireless device: (1) configuration of a plurality of cells comprising at least one secondary cell; and (2) assignment of each of said at least one secondary cell to a cell group in a plurality of cell groups, said plurality of cell groups comprising: (a) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising a primary cell, uplink transmissions by said wireless device in said primary cell group employing a first synchronization signal transmitted on said primary cell; and (b) at least one secondary cell group, a first secondary cell group in said at least one secondary cell group comprising a second subset of said at least one secondary cell, uplink transmissions in said secondary cell group employing a second synchronization signal on an activated secondary cell in said first secondary cell group as a secondary timing reference; and ii) comprising a plurality of dedicated parameters specific to said wireless device, said plurality of dedicated parameters comprising a sequence of at least one first information element, each of said at least one first information element comprising: a first cell group index of a first secondary cell group and a first time alignment timer for said first secondary cell group, wherein for each of said at least one secondary cell: (1) if said plurality of dedicated parameters comprise a cell group index for said secondary cell, assigning said secondary cell to one of said at least one secondary cell group identified by said cell group index; and (2) otherwise, assigning said secondary cell to said primary cell group; b) receiving, by said base station, a random access preamble on random access resources of a secondary cell in said secondary cell group; and c) transmitting a random access response comprising a timing advance command for said secondary cell group.