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justdream
2010-09-29, 03:39 AM
Freinds,

please I need any document about External Neighbors relations as I've to right a report about it
so any data, pics, hints will be highly appreciated

Thanks in advance :hug:

s52d
2010-09-29, 04:18 AM
Freinds,

please I need any document about External Neighbors relations as I've to right a report about it
so any data, pics, hints will be highly appreciated

Thanks in advance :hug:

Hi!
I guess it is about handovers between cell in one BSC/RNC to the cell in another BSC/RNC.
Main difference compared to internal handovers is signaling via several nodes: one or two
MSC/VLR are involved. (Ok, might be IuR)

You can expect sligtly lower performace as with "normal" handovers, mainly due to increased
delay introduced by more signaling. But not much different.
Depending on vendor and RAT, statistics might already be separated (internal/external) or
you have to do it based on target cell.

Any noticeable difference might indicate configuration or dimensioning problems.
Also: if you do not have large cities, and your BSC/RNC areas are properly selected,
there is very low number of external handovers, mainly is low usage area. In this case,
so not worry too much on performance.

BR
s52d

justdream
2010-09-29, 04:37 AM
I need some simple comments about, why we define the BCCH, Cell ID, LAC, BSIC of external cells in the target BSC?
what will be the status in case of wrong definition?

also I need urgently some pictures regarding this issue

s52d
2010-09-29, 05:03 AM
I need some simple comments about, why we define the BCCH, Cell ID, LAC, BSIC of external cells in the target BSC?
what will be the status in case of wrong definition?

also I need urgently some pictures regarding this issue

Hi!

On BSS:
When terminal reports third entry in BA list, say BCCH 42 and BSIC 73,
if it is strong enough, so it is time to make handover.

BSC looks into internal dB and finds out: this is external cell X1.
CGI is used to find signaling path to proper MSC/VLR and ask other BSC to prepare
for incomming handover. If all is OK, BSC receives handover command from the MSC,
and handover is started.

So, without CGI(including LAC and CID)/BCCH/BSIC cell can not be indentified.
If definitions are wrong, there will be no handovers. Or, maybe even worse,
handovers will go to wrong cell, and fail.

For more, please check around: there is a lot of good introduction level docs posted on WFA,
having more detailed description as well as pictures.
If you find description for your vendor, you can get also some performance counters and formulas.


BR
s52d

plannerguy
2010-09-29, 07:25 PM
Adding one more point ....

if you have wrong defnitions in TGTBTS then it may not allow to create the Neighbor Relations.

if your system is siemens take the dump and comapre the param in CREATE BTS AND TGTBTS.


Regards
Plannerguy