- This topic has 67 replies, 1 voice, and was last updated 14 years, 2 months ago by Pix.
5th January 2006 at 23:02 #43351t28Guest
i think, firstly you shoud determine what type of drop call is it : system, radio, HO – check counters
* maybe missing neighbour 🙂6th January 2006 at 02:29 #43352RizGuest
Hi we can use. ZERO command to see if any interference on trx TSs.(e.g I.lev 4).
Also we r using one report numbered 999. I don’t know whether it is custom made for us by the local Nokia vendor.
It tells us bts wise what’s the reason for drop call. Wheather it is trx failures, transcoder fails, failures at A-bis, failures at A interface….
Tk cr.6th January 2006 at 08:31 #43353madhuGuest
1)uplink quality are very weak if the combiner port is having problem, there are two combiner port pls check both the port for the output.
2)Check the type of Antenna used
Madhu6th January 2006 at 14:47 #43354MandyGuest
What do u mean by the measurement from BTS?
Can you tell more.
Izzit the DL from the BTS you refering to?
Tks,6th January 2006 at 15:04 #43355TagGuest
Thanks again for the advice,
Have run through the reports..
H.O,pwr budget all seem ok.
On for my UL quality which is very bad..
My ops team have check all the equipment and all are tested ok.
what we suspect now is external interference.
Any ways to confirm the external interference gor G900?
We have change a no of freqency however the problems is still there.
Thanks6th January 2006 at 15:39 #43356TagGuest
I have a similar report like urs however nothing much can be conclude from there.
As what u have mention,
failures at A-bis, failures at A interface,tch fail call,tch fail old,abis fail call,abis fail old,A if fail call,A if fail call.
Can u kindly explained the reason for the above counters.
cos in my report it does not really tell me much.
Thanks alot!!6th January 2006 at 19:13 #43357t28Guest
I mean, UL level which is measured by BTS and DL level, which is measured by MS and reported to BTS through measurement report…7th January 2006 at 06:37 #43358MadhuGuest
Pls check the CDMA interference.
and check out ur combiner whether it is for GSM and or EGSM
1)900 MHz band Uplink (MS transmitting and BS receiving) frequency range: 890 MHz ~ 915 MHz
Downlink (BS transmitting and MS receiving) frequency range: 935 MHz ~ 960 MHz
2)Extended 900 MHz band Uplink (MS transmitting and BS receiving) frequency range: 880 MHz ~ 915 MHz Downlink (BS transmitting and MS receiving) frequency range: 925 MHz ~ 960 MHz
CDMA also operates in 820-888MHz so there is very high chance of Interference.
CDMA downlink is were close to the uplink of the GSM frequecny so this can be one possible reason for the interference. In this case I suggest you to use BAND PASS FILTERS for the BTS and reduce the interference level.
Madhu7th January 2006 at 07:49 #43359Nitin KhGuest
Well thanks for the info
Its not the spectrum of CDMA which interferes sometimes ..Sometimes its the harmonics of the CDMA which may interfere..Although there always has to be a gaurd band between GSM & CDMA..But the harmonic(byproducts) have varying amplitude & frequency create the problem of interference. So, I personally think interference of CDMA on GSM uplink is irrespective of GSM/EGSM..
Need more discussion on this…7th January 2006 at 09:18 #43360TagGuest
For my network,
We are only using only GSM900/1800.
No CDMA/EGSM in our network.
For now we suspect on it is a illegal transmission third party.
Any advice on this.7th January 2006 at 09:42 #43361MadhuGuest
Ur right Nitin Kh Wht I meant for Mr.Tag is to check the same.
it is always possible for the third party transmission, so better ask your RF Engineer for Drive test using both ur n/w SIM and the competitor n/w SIM
Madhu7th January 2006 at 11:30 #43362Nitin KhGuest
Right Madhu, Illegal transmission is a probability..with the so much of frequency fuss7th January 2006 at 11:34 #43363Nitin KhGuest
Mr. Tag ,
Is it that you dont have any CDMA operator existing in the region you are working.??
Nitin7th January 2006 at 11:50 #43364t28Guest
tag, why don’t you change all frequencies from problematic sector to another sector of this site vice versa ?
it’s work for 10 minutes and you can confirm HW problem or not…
how many TDMAs are in ‘bad’ sector, is there FH ?8th January 2006 at 08:28 #43365TagGuest
Yup there is no CDMA operator in my region.
Ok for the hardware parts we ardy swar the freq and perform various test fron my ops team however there is no problems with the hardware portion.
So far we have 3 sector in our site.
Two of them are having drop call problems,whereas only one of the sector is normal.