Huawei HSDPA affecting EcNo quality

[kentck86]

Hi Experts,

Can anyone tell me or share me any document which related to HSDPA users affecting EcNo quality at cell? Whats the reason causing this, how many HSDPA users are likely to affect on the EcNo quality? Any calculation for this or any idea to prevent HSDPA users from affecting the EcNo quality?

thank you

[LoganTom96]

Basically, EcNo in the cell is more depend on how much power using by traffic (HSDPA or R99) in the cell rather than the number of HSDPA user.
(Off course, more HSDPA user would probably require more power in general, but not totally linear relationship as it depending on the activity and the CQI)

Don't forget that the EcNo is CPICH EcNo, thus, while the CPICH power don't change, the more power used for traffic will definitely cause lower CPICH EcNo.
Let me put some example here:
Assume no inter-cell interference/no noise at all and assume 40 W BTS power and 4 W CPICH and common channel 4 W:
Without traffic: CPICH EcNo = -3 dB
With traffic consuming all the remaining power: CPICH EcNo = -10 dB

There's no way to prevent the HSDPA user to impact the EcNo, what we usually do is to make sure small inter-cell interference as possible (overshooting) then if the EcNo getting wrose than the dimensioning criteria, it means coverage reduced, we have to expand, i.e. more cell/ more frequency.

[kentck86]

Basically, EcNo in the cell is more depend on how much power using by traffic (HSDPA or R99) in the cell rather than the number of HSDPA user.
(Off course, more HSDPA user would probably require more power in general, but not totally linear relationship as it depending on the activity and the CQI)

Don't forget that the EcNo is CPICH EcNo, thus, while the CPICH power don't change, the more power used for traffic will definitely cause lower CPICH EcNo.
Let me put some example here:
Assume no inter-cell interference/no noise at all and assume 40 W BTS power and 4 W CPICH and common channel 4 W:
Without traffic: CPICH EcNo = -3 dB
With traffic consuming all the remaining power: CPICH EcNo = -10 dB

There's no way to prevent the HSDPA user to impact the EcNo, what we usually do is to make sure small inter-cell interference as possible (overshooting) then if the EcNo getting wrose than the dimensioning criteria, it means coverage reduced, we have to expand, i.e. more cell/ more frequency.


Hi LoganTom96,

Appreciate your details explanation, it would be much appreciated if there is calculation on the power consumption per services?

thank you

[LoganTom96]

In live network the power consumption per R99 service varies on time depending on the activity factor of the RB type and also the power control at that moment(and off course the parameter setting, i.e. min, max power, reference bit rate and etc.)
For simulation/dimensioning purpose, the planner may use some fixed value for power of each RB, the fixed value calculated from some assumption but I don't have detail about this.

[tremalnike]

Guys, look here http://www.finetopix.com/showthread.php?31624-CQI-Ec-No-RSSI-amp-RSCP-Explained . Answer is in the attached document .