RACH SR for contention based is very bad while contention free SR is good

RAN
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Hi Experts.

In 5G NSA, what could be the reason of RACH SR for contention based is very bad while contention free SR is good?

Vendor is Samsung.

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Irrespective of vendors and technology among 4G or 5G, this is very first concept of Random access.
So two type Contention based and contention free.

Now your CBRA SR is poor and CFRA SR is good… simple meaning that your initial access is poor and your handover is good.

Analysis:

  1. 1st check high CBRA fail count in particular cells or site. I suspect there may be some sites which are contributing high fails due to over shooting issue. Optimization work will be require maybe start from RET.
  2. If not please check all golden parameters defined by samsung for random access group object type, just compare and correct those parameters as per golden database. Preamble , Ramp and window size and power parameters.

* I hope other expert from Samsung can insight more.

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Thanks!!

In my case, it’s indoor site and only 1 site is affected.

Golden parameters also were checked.

4

Update:

Problem solved!

RACH failures due to high attenuation on Uplink!

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