CPC H04W 74/0833 (2013.01) [H04W 74/04 (2013.01); H04W 74/0891 (2013.01); H04W 76/27 (2018.02)] | 10 Claims |
1. A method of performing a random access procedure, the method being performed by a user equipment (UE) and comprising:
transmitting, as a response to a first random access response (RAR), a message3 (Msg3) for a contention-based random access comprising a first media access control protocol data unit (MAC PDU), wherein the first MAC PDU comprises a cell-radio network temporary identifier MAC control element (C-RNTI MAC-CE) and a radio resource control (RRC) message for a handover completion, and the first MAC PDU is stored in a Msg3 buffer;
if the Msg 3 is transmitted, determining whether contention resolution for the contention-based random access is considered successful; and
in case that the contention resolution for the contention-based random access is considered not successful, performing a contention-free random access procedure,
wherein the performing of the contention-free random access procedure comprises:
transmitting a contention-free random access preamble;
receiving a second RAR corresponding to the contention-free random access preamble;
in case that a size of UL resource allocation in the second RAR does not match with a size of the first MAC PDU obtained from the Msg3 buffer, obtaining a second MAC PDU including at least one MAC subprotocol data unit (MAC subPDU), wherein the at least one MAC subPDU includes the RRC message for the handover completion which is comprised in the first MAC PDU obtained from the Msg3 buffer; and
transmitting the second MAC PDU.
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