Does SQI affect Rxqual ?

Hi Akefa,

rxqual represents the BIT ERROR RATE, not the lost TCH frames.
all the combinations are possible :

good rxqual / good SQI : good situation (normal)

bad rxqual / good SQI : the bit error rate is high (radio conditions are poor), but the encoding of radio allows to rebuild a good speech frame. This is further increased with hopping = ON.

bad rxqual / bad SQI : the protection of the radio is not enough to recompose a good speech frame

good rxqual / bad SQI : several possibilities :
1. the initial speech frame was poorly encoded (problem of TRX hardware, or MS hardware)
2. the received signal is poorly decoded (same as above : hardware problem)
3. too many handovers : handovers affect the SQI (I think ? it affects QVoice) but it for sure doesn’t affect the rxqual. A handover is a blank in the voice, not taken into account at bit level, but it has an impact on the voice (no speech frames are transmitted).
4. half rate : yes, that sounds like a possible case as well. the half rate “quality” is not great, even though all bits are correctly decoded. I suppose the same will happen with AMR.

Actually, do you know how the SQI is calculated ? i think it is explained in the TEMS’s Help.

Pix

hello akefa 🙂

the two main reasons for bad RXQUAL are : interference or bad coverage.

not only interference

in the two networks, the “perceived” quality for customers is the same. The RXQUAL gives an indication of the radio link quality. Keep in mind that between rxqual = 0 and 4, a typical subscriber cannot hear the difference. But a Radio Engineer can already detect a degradation from 0 to 4, and perform necessary corrective actions to prevent an impact on the voice.

On top of that, SQI belongs to Ericsson, and they only know how it is computed. Some networks uses the SQI to assess their network quality as perceived by the subscriber.

I hope that helps ? Let me know if you have comments on this, it is always great to hear different opinions on such matters.

Regards,
Pix

Dear akefa

SQI is composite measure of rxqual and other parameters…bad sqi cannot affect qual..as rx qual is only the measure of BER.

What i want to know is..I want to give away a presentation on Rxqual as well as on Timing advance..

can anyone help me on this regard.

Dear my question is that..

i dnt have that much knowledge regarding timing advance…can you tell me how can i describe timing advance in 5 mins..its theoretical as well as practical aspects.

Thanks

bad sqi depends that whether the two MS users are providing any any audio conversation..if nor u will always find bad sqi.

Also Rxqual is major factor for degrading SQI..

If you are having any issue…Feel free to ask..

Hi All,

Well as i told SQI is composite measure so it also includes the voice transactions b/w two MS. As some times qual is fine SQI is low this occurs with DTX. Sqi also includes DTX. When both the ms are not talking i mean no audio then SQI drops..

Well SQI is more useful in terms that tht the what the consumer is experiencing..

Oh Sorry for mistake!
I means Rxqual degrade is the main caused of SQL degrade