hello ,
after impleme ntation of the parameters RTW is decreased visibly from net act .
We have noted decreased amount of complaints.
BUT problem is not solved. On the other hand that clearly indicated that problem is UL interference.
Honestly my fear is that NSN algo inside hsupa scheduler does not work perfectly.
here is an answer form one of the NSN Rnd guys :
The issues with configuring PrxMaxTargetBTS with high values are:
- The Node B HSUPA scheduler will target PrxMaxTargetBTS so once there are a few HSUPA users in the cell, then the cell will experience high uplink interference increases and uplink coverage will shrink.
- The Node B HSUPA scheduler will become less accurate in terms of being able to target PrxMaxTargetBTS. High values of PrxMaxTargetBTS correspond to operating on the steep part of the exponential load curve. This makes it more difficult for the Node B to be accurate with its estimate of interference floor increases. The variance of the uplink interference floor will increase. The Node B may over-schedule during one instant, then under-schedule during the next instant. This may not be visible from the RNC due to the averaging of the PrxTotal measurements. UE may experience increases in their resource allocations, then decreases in their resource allocations as the Node B attempts to target PrxMaxTargetBTS.
SoThe issues with configuring PrxMaxTargetBTS with high values are:
- The Node B HSUPA scheduler will target PrxMaxTargetBTS so once there are a few HSUPA users in the cell, then the cell will experience high uplink interference increases and uplink coverage will shrink.
- The Node B HSUPA scheduler will become less accurate in terms of being able to target PrxMaxTargetBTS. High values of PrxMaxTargetBTS correspond to operating on the steep part of the exponential load curve. This makes it more difficult for the Node B to be accurate with its estimate of interference floor increases. The variance of the uplink interference floor will increase. The Node B may over-schedule during one instant, then under-schedule during the next instant. This may not be visible from the RNC due to the averaging of the PrxTotal measurements. UE may experience increases in their resource allocations, then decreases in their resource allocations as the Node B attempts to target PrxMaxTargetBTS.
So as a next step we will reduce parameter PrxMaxTargetBTS from 15 to 10 db . By that we will reduce hsupa throughput for 15% but expand congested cells in order to prevent UL interfernce.
Also 2 ms TTI range shell be shrinked by NSN.
This will also affect hsupa throughput but can prevent situations that 2 ms TTI can starve UL .
RNCHSPA- CPICHRSCPThreEDCH2MS WCEL 130 125 RNHSPA- CPICHEcNoThreEDCH2MS WCEL -10 -6
Anyway it is optimization capacity vs quallity.
Good thing is that in RU30 PIC&FDE could compensate throughput loss..hopefully!
keep you updated.
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