| 主权项 |
1. A method comprising:
a) transmitting, by a base station in a plurality of base stations, at least one first control message to a wireless device, said at least one first control message configured to cause in said wireless device:
i) configuration of a plurality of cells comprising a primary cell and at least one secondary cell; andii) 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:
(1) a primary cell group comprising a first subset of said plurality of cells, said first subset comprising said primary cell, uplink transmissions by said wireless device in said primary cell group employing a first synchronization signal transmitted on said primary cell as a primary timing reference; and(2) a secondary cell group comprising a second subset of said at least one secondary cell, said second subset comprising a reference secondary cell, uplink transmissions in said secondary cell group employing a second synchronization signal on said reference secondary cell as a secondary timing reference; and b) transmitting, by said base station, a plurality of timing advance commands to said wireless device, each of said plurality of timing advance commands comprising:
i) a time adjustment value; andii) an index identifying a cell group; and wherein: i) frames and subframes transmission timing for downlink carriers in said primary cell group and downlink carriers in said secondary cell group are substantially time aligned with each other; ii) frames and subframes transmission timing for downlink carriers in said primary cell group and downlink carriers in said secondary cell group of said base station are substantially time aligned with frames and subframes transmission timing of downlink carriers of other base stations in said plurality of base stations; iii) frames and subframes transmission timing for uplink carriers in said primary cell group of said wireless device are substantially time aligned with each other; iv) frames and subframes transmission timing for uplink carriers in said secondary cell group of said wireless device are substantially time aligned with each other; v) frames and subframes transmission timing for uplink carriers in said primary cell group and in said secondary cell group of said wireless device employ:
(1) different synchronization signals as a timing reference; and(2) different timing advance commands; and vi) said plurality of timing advance commands are configured to cause said wireless device to adjust timing of uplink signal transmissions in uplink carriers of said primary cell group and said secondary cell group such that said base station receives said uplink signal transmissions in substantial alignment with frames and subframes of said base station; and wherein frame and subframe timings are substantially aligned when said frame and subframe timings are aligned within an accuracy limit. |
