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Interference on Idle TCH

Viewing 15 posts - 1 through 15 (of 31 total)
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  • #49271 Reply
    Arpan
    Guest

    we generally use stat “Interference on Idle TCH”.. this intf. is uplink or downlink??? how it is calculated???

    #49272 Reply
    Tomar
    Guest

    Hi Arpan,
    This measurement provides the average number of idle TCHs within each interference
    band during the granularity period.
    This measurement is provided in BTS.
    If there is huge amount of higher value there are probably also strong Co- Channels interferences (some type of HW failure, wrong MAIO,…).
    BR
    Tomar

    #49273 Reply
    Arpan
    Guest

    Hi TOMAR

    Thanks for ur Reply..

    Regards
    Arpan

    #49274 Reply
    Gito Prastomo
    Guest

    Hi Arpan,

    Interference on Idle TCH is on Uplink.

    #49275 Reply
    IOI more than 12
    Guest

    IF VALUE CAME MORE THAN 12 THAN WHAT WILL BE THE STEP TO SOLVE THIS (ioi)

    #49276 Reply
    mehrdad
    Guest

    Hi Guys,
    I have a question.
    UL Interference means we have another signal level with same frequency of desired TRX that recieved in Uplink.
    This is my question:
    if RF hopping be active in non-BCCH TRX’s, how the network measures the UL interference? Which frequency will be used for calculating interference? all MA List or not? is my question clear?

    #49277 Reply
    Gito Prastomo
    Guest

    Hi,this is measure on idle tch,not on dedicated,so it is measured on anchor frequency not on Mal list.

    #49278 Reply
    Tomar
    Guest

    Hi All,
    Both, synthesizer hopping and baseband hopping influences this measurement.
    The result is an averaged value of all carriers included in the hopping sequence.
    BR
    Tomar

    #49279 Reply
    Mehrdad
    Guest

    Hi Gito and Tomar,
    Thanks for your reply.
    Gito i think Tomar is saying right.
    Tomar have you any documents that shows UL interference measures on average of all MA freq. list?

    #49280 Reply
    pix
    Guest

    Mehrdad,

    There are 2 different things :

    1. The interference during dedicated mode are detected thanks to :
    – poor RXQUAL (based on Bit Error Rate of current TCH)
    – strong RXLEV
    There is no measure of the actual C/I, even though there is 1 idle timeslot in the 26-TCH multiframe. Note that in the measurement result message on SACCH UL, there is no field for C/I value.

    2. The BTS can measure the UL interference on Idle TCH : when one TS is not busy for CS or PS, the BTS listens to the noise during this timeslot. This is performed on all TRX’s (as far as i recall).

    Regards,

    #49281 Reply
    mehrdad
    Guest

    Hi pix,
    thanks for your reply.the first one is ok.
    i want to check UL intereference from oss. our bss is nokia.i have oss reports that tell me hopping TRXs have intereference (Report 196). you told me the BTS listens to the noise during this timeslots but in which bandwidth? bts have filters, i don’t know the bandwidth of these filters for detecting the level of noise. measuring the level of noise is in 200khz that we define for trx or in whole MA list BW?

    I think BTS listens in BW of all MA list frequencies for each idle time slots and then averages the interference for that time slot. for example if MA list be 84 to 100, BTS listen to frequncy 84 and measures the level of signal in this band then listen to frequency 85 and calculate the level of signal in this freq. band and so on. is it right?

    #49282 Reply
    pix
    Guest

    yes, the BTS listens to the frequencies currently used by their TRX in that TDMA frame.

    it’s very simple indeed : the “empty” UL timeslots of the TRX are measured by the BTS. If the timeslot is using frequency 120, then the BTS will hear the noise on frequency 120.

    At the end of the hour, the indicator shows the average RXLEV of the noise heard on the TS of this TRX.

    Regards,

    #49283 Reply
    TNS
    Guest

    Hi, Pix.

    You said:
    “…
    If the timeslot is using frequency 120, then the BTS will hear the noise on frequency 120…”

    If we haven’t FH at all it’s Ok…

    If we have a SFH with 15 freqs in the FHS, it’s not possible to say which is the freq to be listen to in idle mode.
    In other hand it’s not possible to tune the RX oscilator 15 times per TS to listen all freqs in the FHS…
    So for me it is interesting to know, how the SUMA decides in which idle TS which freq from the FHS to be listen in?

    Pix, what is your opinion, is the idle listening usiful in case of BBH and SFH?

    #49284 Reply
    pix
    Guest

    hello TNS,

    in SFH or in BBH, all TS during one TDMA frame will be emitted and transmitted with the same frequency. At the next TDMA frame, they’ll us the next frequency in the freq list.

    For the BTS, it doesn’t matter which frequency it’ll have the chance to listen at a certain time. Over the hour, it is highly probable that it will have listen fairly to all the frequencies in the list.

    In the end, you get the average rxlev of all the freq. in the list. If BBH/SFH is activated on all cells in the area, the measurement is significant : what matters in terms of interference at network level is the average noise generated by a mix of all frequencies.

    well, that’s my opinion… what do you think ?

    regards,
    pix

    #49285 Reply
    Sierra
    Guest

    Hi all,

    Any body knows what are the causes of no service mode in drivetest idle-lock ? is it possible caused by co channel or adjacent channel interference ?

    Thanks

    BR,
    Sierra

Viewing 15 posts - 1 through 15 (of 31 total)
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