- This topic has 11 replies, 1 voice, and was last updated 12 years, 2 months ago by TNS.
17th January 2009 at 04:16 #55413MKTGuest
This is a unique problem
A BTS site …new one.
Doesn’t have any coverage at all.17th January 2009 at 04:18 #55414MKTGuest
Even all the TRX has been replaced
The BTS is ERICSSON 2964.17th January 2009 at 04:18 #55415MKTGuest
We don’t have any coverage.
Any coverage means NO COVERAGE AT ALL.
It is not like poor coverage or like that, strictly no coverage at all.17th January 2009 at 04:19 #55416MKTGuest
If you have NOKIA handset then you
Are well latched with the cell and the Rxlevels are around -48dBm to -55dBm.
But with Sony Ericsson handsets and Samsung/ Motorola handsets it doesn’t work at all.
Any clue?????17th January 2009 at 07:12 #55417PixGuest
Take 2 days off.
Re-do your tests.
You know, magic doesn’t happen that often in GSM.
Or maybe it’s an evil plan from Nokia, to sell the only handsets that can hear ghosts waves 🙂27th January 2009 at 10:47 #55418OzzieGuest
it’S FunnY PiX 😉27th January 2009 at 15:44 #55419EMGuest
that was really funny27th January 2009 at 19:04 #55420PixGuest
Stop giggling, kids 🙂 MKT has become the first RF “ghostbuster” !
Who you gonna call ??
“… Ghost busters !!”28th January 2009 at 05:08 #55421MKTGuest
Well friends …
I am not kidding here.
I will return back to all of you,
give me some time.
Regards.28th January 2009 at 06:26 #55422MKTGuest
Just see this….
A BTS-1 with LA1 has neighbors (BA list) which a MS1 Continuously monitors and if needed a C2 (cell reselection) is performed.
Another BTS-2 with LA2 is in the BA list of BTS-1 of LA1.
Both BTS-1 and BTS-2 are situated on a Highway.
MS1= Sony Ericsson
The MS1 is in IDLE mode. MS1 is initially camped on BTS-1. The MS1 is moving towards BTS-2. A stage comes when the MS1 performs a cell reselection to BTS-2. Here just note that BTS-1 one is in the LA served by Ericsson MSC and the BTS-2 is in the LA served by Nokia MSC.
A new BTS-3 comes into the network just between BTS-1 and BTS-2 on the highway. The BTS-3 is of LA3. Unfortunately the RF planner did some mistake in defining the BTS-3 as the neighbors of BTS-1 and BTS-2.
With the above inputs, I request you all to give your comments on the scenario which I am describing here….
The MS1 is in the IDLE mode and it is camped on BTS-1 and is moving towards BTS-3. But since the BTS-3 is not in the BA list of BTS-1 no cell reselection was performed. The same happens in case if the MS is camped initially on BTS-2 and is moving towards BTS-3.
Why the MS2 is able to camp on BTS-3?
Assume that MS2 has higher Rx-sensitivity. While moving from BTS-1 to BTS-3 a stage comes when MS1 enters into No service Mode (SOS). While the MS2 is able to reselect a far BTS-4 having LA3. This BTS-4 has BA list which contains BTS-3 as its neighbor.
Isn’t it possible?
MKT28th January 2009 at 08:15 #55423PixGuest
The only way to know for sure is to analyze the traces of a drivetest.
If a MS enters in no coverage mode, you will certainly notice it… I don’t understand why this is a part of your assumption. It either happened or it didn’t.
Other possible scenarios are:
1./ MS2 goes out of coverage, look for the strongest cell in your band >> BTS 3 is selected (not “re” selected)
2./ In the BA list of BTS 1, there is a list of BCCH frequencies that should belong to the neighbor cells.
Therefore it might be possible that the BTS 3 has the same BCCH as one of the neighbors of BTS 1. MS 2 is being fooled, in a way (well, a MS isn’t fooled, ever, it’s just a machine).
3./ Then the difference between MS1 and MS2 can be the sensitivity, but also the processing speed of the results. Two different MS might have noticeable difference in this department, especially in idle mode. Perhaps MS 2 takes a decision 10 seconds after MS 1, so the radio conditions around have changed. MS 1 is already on BTS 1, but MS 2 is out of coverage.. well it’s just an example.
Pix7th February 2009 at 22:49 #55424TNSGuest
About 28 jan cases…
What if Cell3 has a BCCH from some band ( let say e-gsm ), which is supported by MS2, but not supported by MS1…?
Then MS1 will fly over Cell3 without notes it…
Because of the different LACs you have additional Cell Resel Hyst in C2 algorithm…
So you can fly over Cell3 with a combination of CRH value and MS different processing time ( MS1 slower than MS2 ).