top button
Flag Notify
    Connect to us
      Facebook Login
      Site Registration Why to Join

Facebook Login
Site Registration


+2 votes
posted Jul 15, 2018 by Pratap Kumar

Share this question
Facebook Share Button Twitter Share Button Google+ Share Button LinkedIn Share Button Multiple Social Share Button

1 Answer

+1 vote

Random Access Procedure can be initiated by PDCCH order, MAC layer or RRC layer.
MAC will provide the subframe & resources which need to be send for RACH procedure.
PRACH Configuration Index- available set of PRACH resources for the transmission of the Random Access Preamble
ra-PRACH-MaskIndex: Defines in which PRACHs within a system frame the MAC entity can transmit a Random Access Preamble.
Rach will work on Contention-based Random Access Procedure: there is no reserved ra-PreambleIndex and ra-PRACHMaskIndex for the UE. It randomly selects a RA preamble and PRACH resource from a pool defined by the eNB. Contention resolution is needed as multiple UEs in the cell could select the same ra-PreambleIndex and ra-PRACHMaskIndex
Non Contention based Random Access Procedure: UE has already assigned ra-PreambleIndex and ra-PRACHMaskIndex from the network.

answer Jul 17, 2018 by Mohit Mohan
Similar Questions
0 votes

Could any give more insight on this? How exactly Dual SIM mobile uses Modem stack and how attach will happen?

+1 vote

What will be the behaviour of LTE MAC,RLC & PDCP layer once ue data transmission stops & starts again after some time?

0 votes

At handover time target ENB will give rach preamble to UE. Is it necessary that target ENB is to be sink with source ENB. How UE will do contention free rach when both or not in sink? Is their any case Contention free rach will fail?

Contact Us
+91 9880187415
#280, 3rd floor, 5th Main
6th Sector, HSR Layout
Karnataka INDIA.