Patent ID: 8588169

Claim:
A method comprising: a) repeatedly transmitting, by a wireless device to a base station, a first random access preamble on a primary cell until: i) a first random access response corresponding to said first random access preamble is received from said base station; or ii) a first predetermined number of transmissions is reached; b) if said first predetermined number of transmissions is reached without receiving said first random access response: i) indicating a random access problem to a radio resource control layer in said wireless device; and ii) said radio resource control layer determining a radio link failure; c) receiving, by said wireless device, at least one control message from said base station, said at least one control message causing in said wireless device: i) configuration of a plurality of cells comprising said primary cell and at least one secondary cell, said plurality of cells employed for communication between said wireless device and said base station; and ii) 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 a secondary cell group comprising a subset of said at least one secondary cell; d) receiving, by said wireless device, a MAC activation command causing activation of a first secondary cell in said secondary cell group; e) receiving, by said wireless device from said base station and subsequent to receiving said MAC activation command, a control command causing said wireless device to transmit to said base station a second random access preamble on said first secondary cell; f) repeatedly transmitting, by said wireless device to said base station, said second random access preamble until: i) a second random access response corresponding to said second random access preamble is received from said base station on said primary cell; or ii) a second predetermined number of transmissions is reached; and g) if said second predetermined number of transmissions is reached without receiving said second random access response, said wireless device: i) stopping transmission of said second random access preamble to said base station; and ii) keeping a connection with said base station active.