WCDMA UE measurments RSCP and Ec/No

[Mctest]

Hello!Does anybody have detail info on Ec/No calculation in the UE receiver?As it's known Ec/No=CPICH_RSCP/RSSI. How to measure total signal level (RSSI)- it's clear.But how to measure "code power" I mean signal level after despreading?Any detailed information is appreciated.

[s52d]

Hello!Does anybody have detail info on Ec/No calculation in the UE receiver?As it's known Ec/No=CPICH_RSCP/RSSI. How to measure total signal level (RSSI)- it's clear.But how to measure "code power" I mean signal level after despreading?Any detailed information is appreciated.

for example: measure BOTH after despreading. Total received power before filtering,
CPICH_RSCP after filtering.

BR
s52d

[stanislavangel777]

for example: measure BOTH after despreading. Total received power before filtering,
CPICH_RSCP after filtering.

BR
s52d

Hi, S52d !

So, Can I write ? :

Ec/No = CPICH_RSCP / Total_RSCP

Thanks a lot, s52d !!!

[D33T0X]

In dBm is: RSSI=RSCP+EcNo.

[stanislavangel777]

In dBm is: RSSI=RSCP+EcNo.

Hi, D33T0X !

As I understand RSSI is just full RSCP for UARFCH. I can't understand how EcNo influence to RSSI. It's just result of descrembling ? It's the quality of received code.

Thank you for answer,D33T0X !

[Mctest]

for example: measure BOTH after despreading. Total received power before filtering,
CPICH_RSCP after filtering.

BR
s52d

Are you sure that RSSI after despreading?Lets say that despreading=descrambling+dechannelization.If I'm not mistaken CPICH_RSCP is after descrambling and after dechannelization with sf256 all zero.And the question is how to measure level of the digitized signal?I need details!

[stanislavangel777]

Are you sure that RSSI after despreading?Lets say that despreading=descrambling+dechannelization.If I'm not mistaken CPICH_RSCP is after descrambling and after dechannelization with sf256 all zero.And the question is how to measure level of the digitized signal?I need details!

Hello, Mctest !

RSSI is Rx level before descrembling. It's just RxLev of UARFCH.

CPICH_RSCP is Rx level after descrembling.

CPICH_Ec/No is result of filtering after dechanalization.

BLER is block error rate after dechanalization and decoding.

Am I right ?

[Mctest]

Hello, Mctest !

RSSI is Rx level before descrembling. It's just RxLev of UARFCH.

CPICH_RSCP is Rx level after descrembling.

CPICH_Ec/No is result of filtering after dechanalization.

BLER is block error rate after dechanalization and decoding.

Am I right ?

I'm not sure about CPICH_RSCP because it is Received Signal Code Power of the Pilot Channel only.Pilot channel you can get only after dechannelization.

[D33T0X]

It's simple - try my equation on a measurement you have and see if it works :)... RSSI = Received Signal Strength Indicator = Received Signal Code Power (the power of the pilot) + Ec/No (the purity of the signal).

[Mctest]

It's simple - try my equation on a measurement you have and see if it works :)... RSSI = Received Signal Strength Indicator = Received Signal Code Power (the power of the pilot) + Ec/No (the purity of the signal).

Yeah!It is also clear.Because I think that UE measures RSSI and RSCP,then simple division RSCP/RSSI.But the question is how to measure?Especially after despreading. May be by detecting missed zeros after despreading?

[navarubakanth]

It's simple - try my equation on a measurement you have and see if it works :)... RSSI = Received Signal Strength Indicator = Received Signal Code Power (the power of the pilot) + Ec/No (the purity of the signal).

Ec/No = RSCP / RSSI, so in dBm RSCP = (Ec/Io) + RSSI, not RSSI = (Ec/Io) + RSCP

[navarubakanth]

In dBm is: RSSI=RSCP+EcNo.


Ec/No = RSCP / RSSI, so in dBm RSCP = (Ec/Io) + RSSI, not RSSI = (Ec/Io) + RSCP

[blaster949]

As Ec/Io is negative so yes

RSCP= RSSI + Ec/Io

In other words RSCP is LESS than RSSI and the difference is Ec/Io

[Mctest]

As Ec/Io is negative so yes

RSCP= RSSI + Ec/Io

In other words RSCP is LESS than RSSI and the difference is Ec/Io

Thanks!What is about measurement points?

[navarubakanth]

As Ec/Io is negative so yes

RSCP= RSSI + Ec/Io

In other words RSCP is LESS than RSSI and the difference is Ec/Io

Dear bro,

Even Ec/Io is negative or not (but it's always negative otherwise that is not a CDMA based technology) by simple mathematics you can show RSCP = RSSI + Ec/Io;

Ec/Io = RSCP/ RSSI

cross multiply it;

RSCP = (Ec/Io) X RSSI

In dBm,

RSCP = Ec/Io + RSSI (multiplication will become as addition in log)

Thanks

P.S : Don't put unwanted comments without look deeper

This was your first reply...
***************
RSCP is always LESS than RSSI, not greater.

RSCP= RSSI - Ec/Io. You need to go back and learn UMTS.
***************

[navarubakanth]

Thanks!What is about measurement points?

What do you mean by measurement points bro? This is valid always....

[Mctest]

What do you mean by measurement points bro? This is valid always....

I mean where does ue measure RSCP and Ec/No,Is this after demodulation,after multiplication with SC,after multiplication with CC.Someone told us that it is after filtering.What kind of filtering?Digital filtering in Root Raised Cosine filter or after analog filtering?We have 2 pages discussion about how to add or to substract two values and nothing about how to measure level of the digitized signal ("code power").

[s52d]

We have 2 pages discussion about how to add or to substract two values and nothing about how to measure level of the digitized signal ("code power").

After D/A you might try to measure voltage (either peak or rms value) and adjust amplifier gain ...
If you know max amplitude, then it is not so complicated to know power - if you know power,
you are just a logarithm away from EcNo.
Beside Automatic Gain Control, rest is all done in DSP software.


BR
s52d

[Mctest]

After D/A you might try to measure voltage (either peak or rms value) and adjust amplifier gain ...
If you know max amplitude, then it is not so complicated to know power - if you know power,
you are just a logarithm away from EcNo.
Beside Automatic Gain Control, rest is all done in DSP software.


BR
s52d
Thanks!But it would be great to have some kind of documentation with AGC block and DSP details.

[blaster949]

Hi navarubakanth
Sorry for my understanding.
On another note, can anyone please clarify the DIFFERENCE between
SINR and Ec/Nt? with regards to HSDPA

[s52d]

Thanks!But it would be great to have some kind of documentation with AGC block and DSP details.

Yes. I do not recall seeing any book on the topic. Harry Holma has quite lengthy terminal description in his (and others) latest book on LTE. But not to this level of details.
Maybe some general book on DSPs? Maybe even on IS-95 system?

On the other hand, I wonder how terminal TX is done.
In my mind, extreme linearity even with very low TX levels is connected with high battery power consuption. With 16QAM on top ...

BR
s52d

[Mctest]

Hi navarubakanth
Sorry for my understanding.
On another note, can anyone please clarify the DIFFERENCE between
SINR and Ec/Nt? with regards to HSDPA

Simulation of the SINR with planning tool is used for capacity/throughput predictions.
Ec/No it's ue's measurement of the quality of the pilot channel.