US Patent 9949221 Devices for multi-cell communications

A User Equipment (UE) configured for multi-cell communications is disclosed. The UE includes a processor and instructions stored in memory that is in electronic communication with the processor. The UE determines a primary cell (PCell) with a corresponding PCell time alignment timer. The UE also determines a secondary cell (SCell) with a corresponding SCell time alignment timer. The UE further determines whether the PCell time alignment timer is expired. The UE additionally sets the SCell time alignment timer as expired if the PCell time alignment timer is expired.