US Patent 9107206 Carrier grouping in multicarrier wireless networks

A base station transmits an RRC message to modify a first cell group index of a first cell. If the first cell is a primary cell, the RRC message reconfigures the primary cell as a secondary cell with an updated first cell group index and the RRC message comprises mobility control information. If the first cell is a secondary cell, the RRC message releases the secondary cell and adds the secondary cell with an updated first cell group index without employing mobility control information.