GSM vs UMTS Penetration

[tthach830]

I run a rural network with GSM and UMTS. Both on 1900.


To my surpise, GSM signal seems to be stronger than UMTS.

I don't have any empirical data;however, I just get lot of customer complaints saying they don't have service at home or service degraded after 1C/UMTS launched.

[dekili]

Is it on exact frequancy or 1900 and 2100? probelm might be that you have in the case of GSM complete power associated with usefull, users signal (TCH), while in UMTS total power is devided among several channels. UMTS should be weaker but it is compensated by better sensitivity. It is possible that there is high background noise. It could be possible that C/I and Ec/Io is bad. If you consider only propagation issues (propagation loss) it will not depend on technology used.

[tthach830]

It is on exactly 1900 band.

You are correct UMTS has higher sensitivity than GSM.
I think the GSM sensitivity is -110 and UMTS is -115 to -125 on the BTS/NodeB.

Do you know the path loss between the two technology.

[wolverine]

I think the most basic question should be, are both systems using the same Tx power?

[bengurion]

La diferencia puede deberse a diferentes factores de la GSM y UMTS :

.- Los tilt Eléctrico y mecánicos.
.- Potencia de salida de la celdas.
.- Interferencia.
.- pilot pollution o mala calidad del Ec/Io.
.- Potencia del canal piloto de UMTS (SC).
.- Modelos antenas.
.- Cantidad de trafico de UMTS, debido a que en celdas de alto trafico en UMTS puede producir que disminuya la cobertura.
.- Sensibilidad de las celdas.

[adewijaya]

The difference may be due to different factors of the GSM and UMTS:

.- The electrical and mechanical tilt.
.- Output of the cells.
.- Interference.
.- Pilot Pollution or poor quality of Ec / Io.
.- Power UMTS pilot channel (SC).
.- Models antennas.
.- Number of UMTS traffic because of high traffic in cells can result in a decrease UMTS coverage.
.- Sensitivity of the cells.

[dekili]

The difference may be due to different factors of the GSM and UMTS:

.- The electrical and mechanical tilt.
.- Output of the cells.
.- Interference.
.- Pilot Pollution or poor quality of Ec / Io.
.- Power UMTS pilot channel (SC).
.- Models antennas.
.- Number of UMTS traffic because of high traffic in cells can result in a decrease UMTS coverage.
.- Sensitivity of the cells.


True...
But this is the network in rural area thus traffic is low and cell breathing will not be seen. I assume that same antennas with same parameters are used since same frequency band is in question. It seems from initial message that signal strenhgt is the problem. It could be only the power of UMTS pilot channel...

[tthach830]

As per market std, we allow allocate 8% of maxtransmitpower to CPICH power. I haven't done a audit to see if the power match the GSM power. I believe they do match. I will get back to that.

We use the same antenna.

[bengurion]

As per market std, we allow allocate 8% of maxtransmitpower to CPICH power. I haven't done a audit to see if the power match the GSM power. I believe they do match. I will get back to that.

We use the same antenna.
you can vary the CPICH, but keep in mind that this will vary the coverage. The higher CPICH will have more coverage but less capacity

[Egorka]

A stupid question: You do not use those technologies on exactly the areas, do you?
Else they interfere each other, since they use the same band... BTW, what is the vendor?