Help: High power congestion with low user activity (3G E*******)

[linhhy]

Hi all,

Currently I've met difficult case what I need help from expert. In our network, there are many congestion cells with very low traffic. I had some analysis but still now no clear root cause got.
When I trace on RNC some cells used high power even low user as below.
anyone have any idea to help me please!

RCPD32> cedr -c 3HN883B

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MOD CELL cid fro ro PwrDl/Adm dlCode ulInt sf8d sf8u sf16d sf16u sf32d sf4u dlASE ulASE CPMcn HScnt EULs EULns Eul2 Spch CC_SP
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1081 3HN883B 18322 824 82 70.0% 75% 14.8% -106.9 0/0 0/50 0/16 1/50 0/32 0/0 1.5/500 8.8/500 0/15 2/30 1/16 0/16 0/2 0 0/0 4 2 1081:0017sp0
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Total (1 cells): 0 0 0 1 0 0 1.5 8.8 0 2 1 0 0 0 0 4 2
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RCPD32> cedr -c 3HN883B

130701-15:15:53 10.59.240.249 9.0g RNC_NODE_MODEL_M_1_200 stopfile=/tmp/4997

------------------------------------------------------------------------------------------------------------------------------------------------------------------
MOD CELL cid fro ro PwrDl/Adm dlCode ulInt sf8d sf8u sf16d sf16u sf32d sf4u dlASE ulASE CPMcn HScnt EULs EULns Eul2 Spch CC_SP
------------------------------------------------------------------------------------------------------------------------------------------------------------------
1081 3HN883B 18322 824 82 58.4% 75% 13.6% -107.1 0/0 0/50 0/16 2/50 0/32 0/0 1.5/500 6.8/500 0/15 2/30 1/16 0/16 0/2 0 0/0 1 2 1081:0017sp0
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Total (1 cells): 0 0 0 2 0 0 1.5 6.8 0 2 1 0 0 0 0 1 2
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RCPD32> cedr -c 3HN883B

130701-15:17:40 10.59.240.249 9.0g RNC_NODE_MODEL_M_1_200 stopfile=/tmp/4997

------------------------------------------------------------------------------------------------------------------------------------------------------------------
MOD CELL cid fro ro PwrDl/Adm dlCode ulInt sf8d sf8u sf16d sf16u sf32d sf4u dlASE ulASE CPMcn HScnt EULs EULns Eul2 Spch CC_SP
------------------------------------------------------------------------------------------------------------------------------------------------------------------
1081 3HN883B 18322 824 82 66.2% 75% 26.7% -106.3 0/0 1/50 0/16 2/50 2/32 0/0 20/500 18/500 1/15 3/30 3/16 0/16 0/2 0 0/0 0 3 1081:0017sp0
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Total (1 cells): 0 1 0 2 2 0 20 18 1 3 3 0 0 0 0 0 3
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RCPD32> cedr -c 3HN883B

130701-15:18:11 10.59.240.249 9.0g RNC_NODE_MODEL_M_1_200 stopfile=/tmp/4997

------------------------------------------------------------------------------------------------------------------------------------------------------------------
MOD CELL cid fro ro PwrDl/Adm dlCode ulInt sf8d sf8u sf16d sf16u sf32d sf4u dlASE ulASE CPMcn HScnt EULs EULns Eul2 Spch CC_SP
------------------------------------------------------------------------------------------------------------------------------------------------------------------
1081 3HN883B 18322 824 82 77.8% 75% 14.8% -106.2 0/0 0/50 0/16 1/50 0/32 0/0 2.6/500 11/500 0/15 3/30 1/16 0/16 0/2 0 0/0 1 3 1081:0017sp0
------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total (1 cells): 0 0 0 1 0 0 2.6 11 0 3 1 0 0 0 0 1 3
------------------------------------------------------------------------------------------------------------------------------------------------------------------

[chefo]

Hi there,

According to the values you haven't got congestion yet, but the low traffic shows there is something that needs to be checked.

I would first make a Propagation Delay analysis, the most common reason for high DL power utilization is cell radius too large. Check how far is your traffic coming from. Then you check your power sharing parameters between R99 and HSDPA, perhaps you dedicate too much power to HS?

Post your results, so you can get more help, or if you solve it, post the solution, so the others can learn from this.

Cheers!

[rabkalamek]

Hi there,
i'm newbie in network optimization. But in my experience, as chevo said high overshoot coverage (Based on propagation delay) can make high congestion in 3G. i don't know if its in line or not, but neighbor optimization can cause reducing the power consumption. Sometimes the configuration of maxdlpowercapability, maximumtranspower & primarycpichpower should be setting with acceptable value.

Based on my brief experience in telco, maxdlpowercapability & maximumtransmissionpower should be set with minimum difference value (0.1-0.2dbm) or maybe same value. the primarycpichpower normally should be set 10% of maximumtransmissionpower. so if maxtrans setting 446 you can set cpich to 346, or another high value with optimum value of poweradm & poweroffset.

cmiiw, i'm just newbie with curious of criticism :)

[Philippe]

If you have enabled HSDPA, it is normal to have high usage of DL power as a user in HSDPA will trend to use all the remaining power to have good throughput performances (unless a limited dedicated power is assigned to HSDPA).
If R99 traffic, the power consumed by a user will be high if the service used is high bit rate (e.g. PS 384) and if the user is at the cell edge (power control behaviour). This is not an issue. In UMTS, your admission threshold can be higher than 75%: around 90-95% is acceptable.