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EiRP & Rx Level Strenght

Viewing 15 posts - 1 through 15 (of 20 total)
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  • #49498 Reply
    Ziya Akhundov
    Guest

    Hi, All
    I would like to know about diversity of these parameters. When we calculate EiRP of Site it be 45dbm, 50dbm and etc. And also Rx Signal Level are measured by dbm. For example in the same cell EiRP is 46dbm and average signal level (RxLevel) is -38dbm. Who can explain difference of these parameters??? 🙂
    Thanks

    #49499 Reply
    Pix
    Guest

    Hello Ziya

    The difference is due to the propagation of the radio waves. Apply this formula :

    EIRP – Path Loss

    And you should find your “-38dBm”

    with Path loss =
    20.log(d) + 20xlog(f) + 32.44

    with d : distance in km
    f : frequency in MHz (900 MHz)

    Regards,
    Xabvier

    #49500 Reply
    emre igrek
    Guest

    with Path loss =
    20.log(d) + 20xlog(f) + 32.44

    Xlog ?

    #49501 Reply
    pix
    Guest

    “x” means “multiplied by”

    FYI, these are log10.

    The whole formula is in wikipedia (search “free space loss”)

    regards,

    #49502 Reply
    Asa
    Guest

    Hi Ziya,

    EiRP(dBm)=AntenaPower+AntennaGain, it should be constant in any area served by a given cell,
    RxLevel=EiRP-Path Loss,it depends on the distance from an antenna+environment terrains.

    #49503 Reply
    Ziya Akhundov
    Guest

    Hi, All
    Very thanks for your explain.
    And also I have a question. I work in telecommunication company and I have a big problem with other departments that I found an abnormal situation in BTS room. 1/2′ cables was rounded (two times) on BTS. I think it is very big signal loss, but they say me that it is standart. I would like to prove it is not right, so I need some documents about this problem. Please help me about this situation. Thanks

    #49504 Reply
    pix
    Guest

    ziya,

    you can refer to the vendor’s catalogue of those cables. Normally each cable is defined by a certain set of “physical charasteristics”, such as attenuation dB/m, weight, thickness, etc.
    One of those characteristic is the “minimum bending radius”

    Definition of the bending radius here : en.wikipedia.org/wiki/Bend_radius

    In your case (double circle), you should use the “minimum radius for repeated bends”.

    If you cannot find you cable vendor’s catalogue, you can refer to RFS catalogue (online) :
    www dot rfsworld.com/index.php?p=289&l=1&mode=hierarchy

    for 1/2″ : min radius repeated bends = 125mm (corrugated) or 32 mm (superflexible). Basically, even with the roughest 1/2″ jumper, you can do narrow circles of min. 25cm diameter (corrugated) or 7cm (superflexible).

    Regards,

    #49505 Reply
    Ziya Akhundov
    Guest

    Hi, All
    How can explain me what is RLT (Radio Link Timeout) ? Thanks a lot…

    #49506 Reply
    pix
    Guest

    radiolink timeout is a mechanism in the BTS and in the MS.

    Let’s look at the BTS side :

    Every time the BTS receives a good SACCH frame that can be decoded, the radiolink counter remains at its maximum value (if already at max value) or it is incremented by +1.

    Every time the BTS receives a SACCH frame that cannot be decoded (probably because of poor radio conditions, degrading the signal), the RL counter is decreased by -2.

    Initially the value of the RL counter = 18 (parameter RADIO LINK TIMEOUT BS).

    Once the value reaches 0, the call is dropped (radio resource is dropped, message sent to the BSC).

    At MS side, it is the same, except that when it reaches 0, the MS decides to release the call by itself. Therefore, it doesn’t send a message to the BTS.

    Regards,

    #49507 Reply
    Ziya Akhundov
    Guest

    Hi, Pix. Thanks a lot for your explains. I have another question. Can you explain a large form of Cell Priority? Thanks: regards
    Ziya

    #49508 Reply
    pix
    Guest

    cell priority sounds a bit vague, this term is not used in alcatel systems so i’m not sure what it refers to.

    #49509 Reply
    Ziya Akhundov
    Guest

    Ok, thanks Pix. But I have another question.How many subscribers can use EDGE at the same time in the same timslots? (For example I have a static TRX for EDGE)

    #49510 Reply
    pix
    Guest

    hello zuya,

    the answer to your question depends on the value you set to the parameter that controls it.

    max value : 6 TBF per PDCH in UL and 10 TBF per PDCH in DL.

    Parameter name : MAX UL TBF PER PDCH and MAX DL TF PER PDCH. Default values are almost the max values : operators perfer to reduce the throughput per user but allow more users to be connected at the ame time. Quantity over Quality…

    #49511 Reply
    Ziya Akhundov
    Guest

    Hi, Pix. Thanks for your explain.
    I would like to ask that in the maximum TA (Timing Advance-I think it is 35km)can I talk on the phone if signal level is (-80dbm)???
    Is it possible?
    Regards:

    #49512 Reply
    pix
    Guest

    well, yes, if rxlev is good and TA is within 35km, then it should be possible. Assuming there are no interference (good rxqual), of course.

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