top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

LTE: When Contention Free RACH procedure will fail?

0 votes
1,509 views

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?

posted Jul 29, 2015 by anonymous

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

0 votes

On behalf of Venumadhav Josyula

Contention free RACH is designed such that enodeB accolate dedicated preambles for UEs such that there is absolutely not possibility of collisions. So it will never fail under decent radio conditions. So according to me it should will never fail ... :) faulty UE or enobeB does not guarantee it...

answer Jul 29, 2015 by Salil Agrawal
Their should be sink between two ENB's (source and target)? Is it needed?
commented Jul 29, 2015 by Manohar Venkat.ch
I am also facing the same problem...
Because in our case both Enbs are in sync with GPS but UE is still failing to do the contention free rach on the dedicated  preamble and prach config index given by source ENB, So what could be the possible reason for contention free rach failure???
commented Jul 29, 2015 by Ashish Barapatre
Similar Questions
+2 votes
LTE: How source eNodeB get to know when it has to trigger handover required message towards MME ?

I have basic handover related query. How source eNodeB get to know when it has to trigger handover required message ? I mean to ask, how a source eNodeB come to know the threshold values of RSRP or RSRQ or both (related to target eNodeB) , required to do a successful handover towards eNodeB ? Is it due to network planning ?

+1 vote
LTE: Why frequency offset is not considered for leaving and entering condition of event A6 ?

Unlike for A3 and A5 events, for A6 event frequency offset is not considered while evaluating entering and leaving condition. Can anyone please explain this particular case ?

+2 votes
LTE: How different threshold values are derived for different event like A1, A2, A3, A4 and A5 ?

I was going through the measurement configuration sends from eNodeB to UE in RRC Connection Reconfiguration message.
I saw that multiple events have been defined and are used. Couple of parameters are considered to detect entering and leaving condition of an event for example event A1. Now I have a question "Threshold and Hys values are same for all the cell or it may different". Does the standard define the value of all these parameters or network operator defines ? If network operator does then what are points to derive these values ?

+2 votes
Events A2 or A3 determine interfrequency and intrafrequency HO within LTE system...

is there any specific events in LTE that support only interfrequency and intrafrequency HO ... kindly specify in detail how

...