| 主权项 |
1. A method comprising:
a) receiving, by a base station from a wireless device, a buffer status report on a first cell in a plurality of cells, said buffer status report indicating an amount of data available for transmission in at least one uplink buffer of said wireless device, said first cell being assigned by said base station to a primary cell group; b) transmitting, by said base station to said wireless device, a control command for transmission of a random access preamble by said wireless device on a secondary cell in said plurality of cells if said base station determines:
i) based on said buffer status report, that radio resources of said secondary cell are required for transmission of a portion of said data in addition to radio resources on said primary cell group; andii) that said secondary cell requires a first uplink timing that is different from a second uplink timing of said primary cell group; c) receiving, by said base station from said wireless device, said random access preamble on said secondary cell, said secondary cell being assigned to a secondary cell group, wherein transmission timing of said random access preamble is determined based, at least in part, on a first synchronization signal transmitted by said base station on said secondary cell group; d) transmitting, by said base station to said wireless device, a random access response on a primary cell of said primary cell group, said random access response comprising a timing advance command for said secondary cell group; and e) transmitting, by said base station to said wireless device, at least one control packet comprising transport format information and resource allocation information for transmission of a plurality of packets of said data on said secondary cell. |
