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Does SQI affect Rxqual ?

Viewing 15 posts - 1 through 15 (of 22 total)
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  • #49828 Reply
    akefa
    Guest

    Rxqual is the percentage of the lose of tch frame.

    CQI is a measure of the quality of the speech.

    It is logic that bad Rxqual will resuilt with bad CQI

    What about the opposite??
    In other words: does SQI affet the Rxqual?

    for example: In case of bad SQI (for ex. due to half rate or handover) does it resuilt with bad Rzqual?

    #49829 Reply
    Pix
    Guest

    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

    #49830 Reply
    akefa
    Guest

    Dear Pix, thanx for your nice answer and usefull details.

    That means….

    The bad Rxqual is resuilted in bad conditions in the air interface

    The the only reason of bad Rxqual is interference

    One more question:

    Two networks:
    Network A: SQI=30, Rxqual=0
    Network B: SQI=30, Rxqual=2

    Is the quality same for both customers of the two netowrk?

    If the answer is YES, I am wondring why engineers take the Rxqual (not the SQI) in the benchmarking ?!

    #49831 Reply
    pix
    Guest

    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

    #49832 Reply
    sam
    Guest

    what is the industry standard value for SQI

    #49833 Reply
    Ahsan
    Guest

    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.

    #49834 Reply
    pix
    Guest

    ahsan

    what is your question actually?

    #49835 Reply
    Ahsan
    Guest

    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

    #49836 Reply
    krishnan
    Guest

    Please tell me the reasons for BAD SQI

    #49837 Reply
    Ahsan
    Guest

    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..

    #49838 Reply
    uji
    Guest

    in tems sqi is directly proportional to fer.
    during hard handovers there is a loss of frame which effects sqi badly.
    rx qual is directly proportional to ber.

    #49839 Reply
    Ahsan
    Guest

    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..

    #49840 Reply
    Phantom
    Guest

    Conclusion;
    SQI is the main effect to SQL degrade . In normally but not always ,SQI will be bad if Rxqual is going bad ( trig 5-6 )
    for more cleared , have you ever see SQI while mobile hold with HalfRate TRX ? that you can see SQI will be half (15) of (30) that means the voice quality degraded 50% and users can perceive.

    #49841 Reply
    Phantom
    Guest

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

    #49842 Reply
    Partha
    Guest

    Whats the main relation between the two actually?

Viewing 15 posts - 1 through 15 (of 22 total)
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