 Station Identifier [4] or in case the UE was never previously attached to the network, random value) from message 3 contents based on which the UEs can identify the correct message 4. Several UEs can select the same random access resource, that is, use the same RA-RNTI, and select randomly the same random access preamble and therefore several UEs can receive random access response that is not intended for them and send message 3. Then finally only message 4 reception (the contention resolution part of it) can identify the correct UE for which the random access response was intended to and for which the RRC connection is being setup. Message 4 uses adaptive HARQ and the HARQ feedback is sent only by the UE which identifies its own UE identity, used in message 3, from LTE Small Cell Optimization contention resolution message. If coincidentally any other UE chose the same RA-RNTI and the same preamble, it would now understand that there was a collision and it would start the random access process from the beginning by transmitting a new preamble with increased transmission power (i.e. PREAMBLE_TRANSMISSION_COUNTER is incremented by 1). The UE for which message 4 was intended to responds with HARQ acknowledgement (in case correct decoding of the whole message 4) and stops the contention resolution timer and prepares to send message 5. While the contention resolution timer is still running in the UE (started when message 3 was transmitted) and the UE receives negative acknowledgement for transmitted messag 3, the UE will retransmit message 3 and restart the contention resolution timer at each retransmission of message 3. After transmission (or retransmission) of message 3, the UE monitors the PDCCH resources identified by temporary C-RNTI (given in the random access response message) for message 4 capacity grant until the expiry of contention resolution timer. If the contention resolution timer expires, contention resolution is considered unsuccessful and the UE is expected to start the random access procedure from t