1. Contention Based Random Access
过程 1: RRC establishment or RRC reestablishment
CCCH logical channel (RRC establishment or RRC reestablishment)
过程 2: RRC handover on DCCH1 without the rach-ConfigDedicated configed
NONE- CCCH logical channel
过程 3: PDCCH order
NONE- CCCH logical channel
2. None-Contention Based Random Access
过程 4: RRC handover on DCCH1 with the rach-ConfigDedicated configed
NONE- CCCH logical channel (PDCCH order or RRC handover on DCCH1)
《过程描述》
过程 1: If CCCH logical channel (the CCCH SDU is included in Msg3)
- MAC initializes random access
- ENB sends random access response (with temporary-CRNTI and UL-Grant) to UE
- MAC sends the Msg3 with CCCH-SDU (with RRC connection establishment or reestablishment request message UEID: 5bytes ;Establishment cause: 1 byte) to ENB on the received temporary-CRNTI
- MAC starts contention resolution timer
- ENB sends RRC connection establishment or reestablishment response message with MAC control element (UE Contention Resolution Identity) to UE on DL-SCH on the temporary-CRNTI
- MAC matches the UE Contention Resolution Identitywith the CCCH-SDU (checking the UEID)
- If matches
a. Stop contention resolution timer
b. Set the temporary-CRNTI to the C-RNTI
c. Send the RRC connection establishment or reestablishment response message to RRC
d. Random Access procedure successfully completed
- Else
a. Random Access procedure failed
过程 2, 3, 4: If NONE- CCCH logical channel (the C-RNTI MAC control element is included in Msg3)
- MAC initializes random access
- ENB sends random access response (with temporary-CRNTI and UL-Grant) to UE
- if ra-PreambleIndex was explicitlysignalled and it was not 0 (handover with the rach-ConfigDedicated message configed) <过程 2>
a. MAC does not start contention resolution timer
b. MAC sends the ULdata (e.g. RRC Connection Reconfiguration Complete- handover complete message on DCCH1)by the assigned UL-Grant on the C-RNTI (not temporary-CRNTI)
c. The Random Access procedure successfully completed
NOTE: I think no Msg3 transmission in this procedure<过程 2>.
- Else (PDCCHorder or handover without the rach-ConfigDedicated message configed) < 过程 3, 4>
a. MAC sends the Msg3 with C-RNTI MAC control element (original C-RNTI for PDCCH or the assigned C-RNTI for handover) to ENB on the received temporary-CRNTI
b. MAC starts contention resolution timer
c. If ENB sends PDCCH notification on C-RNTI (the C-RNTI sent in the MAC control element , not temporary-CRNTI)
· stop mac-ContentionResolution Timer
· discard the Temporary C-RNTI (use the original C-RNTI or the assigned C-RNTI for handover)
· use the UL grant included in this notification for a new transmission
· Random Access procedure successfully completed
Else 《对应 c if》
If mac-ContentionResolution Timer expires
Random Access procedure failed