Patent ID: 8644129

Claim:
A method comprising: a) receiving, by a wireless device, at least one radio resource control (RRC) message from a base station, said at least one RRC message: i) causing configuration of a plurality of carriers comprising a first carrier and at least one second carrier; and ii) comprising a carrier group index for a second carrier in said at least one second carrier, said carrier group index identifying a carrier group, said carrier group being one of a plurality of carrier groups, said plurality of carrier groups comprising: (1) a first carrier group comprising a first subset of said plurality of carriers, said first subset comprising said first carrier, uplink transmissions by said wireless device in said first carrier group employing a first synchronization signal transmitted on said first carrier as a first timing reference; and (2) a second carrier group comprising a second subset of said at least one second carrier; b) receiving, by said wireless device from said base station, a control command causing said wireless device to initiate a random access procedure; c) transmitting to said base station a second random access preamble on said second carrier; d) if no second random access response corresponding to said second random access preamble is received within a random access response window and if a second counter of said second random access preamble transmissions is below a second predefined value, repeating (c) and (d); and e) if said second counter reaches said second predefined value without receiving said second random access response, said wireless device: i) completing said random access procedure; and ii) keeping an RRC connection with said base station active.