Nokia HSDPA High BTS Failures

[mitch_jones02]

Hi,
Would like to ask everyone if you experienced already Nokia sites with very high BTS failures. This problem occurs during busy hour and when HSDPA attempts > approx 6000/hour.
Please note that
- Nokia RU40
- BB util and R99 CE is low around 40%
- HSDPA users is also low and below 240 (WBTS)
- HSUPA users is also low and below 240 (WBTS)
- T'put steps were okay, set to 18.
- HSDPA PS: 6 HSUPA PS: 10 R99CE: 768
- HW: FSMF+FBBA
- Iub: some sites were highly utilized (>70%), some were low.

[dtvt2]

Hi friend
- Pls check how many local cell group are there
- Try ping test with MTU 1500 at peak hour

[mitch_jones02]

Thanks friend. We've tried already activating 2 local cell group for some sites with high users but still no improvement.
For sites with low users, there's only 1 LCG since WBTS users is around 100 only.

Will try ping test during BH.

[william.dg08]

Hi, check the control plane capacity. Use the following counter:

M5004C1 / PEAK RL SETUPS PER SECOND
Description: Peak radio link setup messages handled per second, where handled means setups
that are not rejected because of congestion.

There are some limitations, for control plane
56 RL/s (2FSME)
22 RL/s (1 FSMD)
70 RL/s (FSMF + 2xFBBA)

W./

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[william.dg08]

By the way, for more detail about CAPACITY, check the following doc:
"Managing WCDMA RAN and Flexi Direct Capacity"
Issue 03I
Approval Date 2014-09-19
127 pag.

This doc appear in Information Browser Library RU40 (new NOKIA NED )

W./

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[mitch_jones02]

hi william, actually i've also checked that one and Average RL setup message queuing time, it's normal.
One thing i've noticed is that BTS failures occurs when HSDPA attempts reaches around 6000 per cell per hour.

Nway, i will double check again Peak RL setups to verify.

[mitch_jones02]

hi i've check peak RL setups, max is only 10 for two sites (FSMF+FBBA).
any other idea?

[dtvt2]

which transmission type do you use? IP or ATM

[mitch_jones02]

Transmission type is IP.
BTW, we're encountering BFD link failure for those sites with high Iub utilization. And that BFD link failures pertains to Iub capacity already (for upgrade).

[Lamboy]

Hi there,
have u checked Congestion control frame from 067?
if there are a lot loss appear, escalate to transport team.

BR//