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Hi Guys
I’m facing with big problem, I hope you will help me.I see strong interference in hopping channels (Huawei BTS). I checked all hopping parameters (MAL, HSN, BCCH, BSIC, MAIO) but cann’t find any abnormal thing. This problem happens on many sites, not only one sites.
I’m expecting for your helps,
TanksHello Ziko,
Could you please list, for the 6 cells of two neighbours BTS :
– Hopping frequencies for each TRX of each cell
– MAIO for each TS
– HSN for each TRX
– and also the BCCH frequencies.I hope that’s not too much trouble, but that’s the only way I can check your settings.
Hi Pix
for example, to the same place two sites are serving:
SiteA{1} MAL(25-41),HSN(42),MAIO(0.6.12),BCCH(16)
SiteA{2}
MAL(25-41),HSN(42),MAIO(2.8.14),BCCH(9)SiteA{3}
MAL(25-41),HSN(42),MAIO(4.10.16),BCCH(3)__________________________
SiteB{1} MAL(25-41),HSN(41),MAIO(0.6.12),BCCH(22)
SiteB{2}
MAL(25-41),HSN(41),MAIO(2.8.14),BCCH(3)SiteB{3}
MAL(25-41),HSN(41),MAIO(4.10.16),BCCH(11)Interference happens in Hopping Channels, not in BCCH channels. Please, I’m waiting for your quick reply
Thanks
ZikoHi,
Ok, the SFH parameters are perfect, so I assume you are experiencing “normal” interference.
Let’s see.RF LOAD = 3 / 17 (# TRXs / #hopping frq) = 17.6%
The threshold is 12%.
It means that your frequencies are way too much used !! There are plenty of collisions between cells : the probablity that 2 cells are using the same frq is just too high !
How to fix :
1/ add frequencies in the MA List
or
2/ remove some TRX in order to have only 2 hopping TRX per cell
or
3/ roll back to BBH and do your FP manually.Just for information, what is the average call drop rate in this area, at busy hour and daily average ?
Hi Pix,
1st question is about:
RF LOAD = 3 / 17 (# TRXs / #hopping frq) = 17.6%
Could you explain this formula?
2. Call Drop Rate is not more, but I mean bad quality. In hopping I think RxQuality can be (1-5). But in my sites’ quality amount is (5-7). also I feel in real time when I call (bad speach)
3. As well take into account that this sites are located in BSC borders (both of BSC sites have hopping)
Thanks in advance:
Ziyahttp://www.erlang.com/forum/erlang/thread.htx?thread=5388
2/ bad quality but no call drop ? i’m sure that if the quality gets better, the call drop will be even better.
3/ BSC border and voice quality are not correlated. There could be a slighlty longer delay before detecting a HO, but that would not decrease the rxqual so badly.
cheers,
pixThanks Pix,
What is cause of this problem?
There are 22 sites and devided to two part (2 BSCs). RxQuality is very bad in the BSC borders. These site have been drive tested and 4 drops occured due to bad quality in hopping channels. Neighbours are ok. HSNs are ok. MAIO ok. BCCH ok.But what is problem???
Thanks
ZiyaDear Ziko,
do you use downlink power control ?BR
dear Ziko,
with although respect i want to express my point of view. if you are sure that your every setting is perfect. pls check 2 other possibility.
1- make sure all your sites has the standard azimuth.
2- make sure that your cells doesnt have overshooting.bkz these options also could be the cause for increasing bad quality.
thanks,Hello,
I agree with Mohttat, I think it is a radio problem : your rf load is too high. It’s clear that this will cause a problem.
Why at bsc border ? It’s probably a coincidence.Of course, you can support your assumption (that it is NOT a radio problem) by sharing some qos data : CDR for each cell, TCH traffic per cell, and mention which cells are located at bsc border, among the list.
Hi,
Thannks a lot for yoyr commentsActually Azimuths are not standard, because we use 1×1 SFH.
Also we have some overshooting sites.
Maybe cause is this…
Thanks
ZikoHello Ziko,
Did you solve the problem?
What was the cause?
thanks
J.Hi Junior
Actually the problem has not been solved completely, but İ have activated DL Power Control. After that I can say it solved 40 %.
BR,
Ziko
