Transmission timing based on a secondary cell in a wireless device

摘要

A wireless device receives configuration parameters of cells grouped into timing advance groups (TAGs). The TAGs comprise a secondary TAG comprising licensed secondary cell(s) and unlicensed secondary cell(s). Activation command(s) to activate the licensed secondary cell(s) and the unlicensed secondary cell(s) are received. A first secondary cell in the secondary TAG is selected as a timing reference cell for the secondary TAG based on: the first secondary cell being an activated secondary cell, and the first secondary cell being a licensed secondary cell. uplink signals with transmission timing derived based on the first secondary cell as the timing reference cell are transmitted via the secondary TAG.