1. A wireless device comprising:one or more processors; and
memory storing instructions that, when executed by the one or more processors, cause the wireless device to:
receive at least one message comprising configuration parameters of a plurality of cells grouped into a plurality of cell groups, wherein the plurality of cells comprises a plurality of downlink-uplink cells and at least one downlink-only cell, wherein:
each cell group of the plurality of cell groups comprises at least one of the plurality of downlink-uplink cells; and
each of the at least one downlink-only cell is assigned to a cell group comprising at least one of the plurality of downlink-uplink cells;
receive a timing advance command comprising a time adjustment value and an index of a first cell group of the plurality of cell groups; and
apply the timing advance command to uplink transmission timing of at least one downlink-uplink cell, of the plurality of downlink-uplink cells, associated with the first cell group.