Method for performing random access and terminal for performing same
摘要
說明書
A method of including information capable of identifying UE includes two types of methods. If the UE has already had a valid cell ID allocated thereto in a corresponding cell before performing random access, the UE transmits its own cell ID through an UL grant. In contrast, if a valid cell ID has not been allocated to the UE prior to a random access process, the UE transmits data including its own unique ID (e.g., an S-TMSI or a random ID). In general, the unique ID is longer than a cell ID. If the UE has transmitted the data through the UL grant, the UE starts a timer for a contention resolution (contention resolution timer).
After the UE receives the random access response and transmits the data including its own ID through the allocated UL grant, the UE waits for an instruction from the eNodeB for a contention resolution (S840). That is, the UE attempts to receive a PDCCH in order to receive a specific message. Two types of methods can be proposed as a method of receiving a PDCCH. If its own ID transmitted through the UL grant as described above is a cell ID, the UE can attempt to receive a PDCCH using its own cell ID. In this case, if the UE receives a PDCCH through its own cell ID before the contention resolution timer expires, the UE determines that the random access has been normally performed and terminates the random access. If the ID transmitted through the UL grant is a unique ID, the UE attempts to receive a PDCCH using a temporary C-RNTI included in the random access response. In this case, if the UE has received a PDCCH through a temporary cell ID before the contention resolution timer expires, the UE checks data transferred through a PDSCH indicated by the PDCCH. If its own unique ID is included in the data, the UE can determine that the random access has been normally performed and terminate the random access.
