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View Full Version : What if BTS-BSC link down for bcch?



Mr_Piongly
2009-06-13, 11:51 PM
Hi all,

I am asking what happen if the link between BTS and BSC goes down (for example as in the case of hardware faults for microwave link ).

In this case the BTS:
1) continue to transmit the BCCH or
2) BTS stop the BCCH transmission

In the first case 1 above the users receive a signal (bcch) and could try to make a call that will be rejected (for sdcch block)?

In second case simply the users will not have coverage ( if we assume that there are not other useful cells in the area)

Who can explain what really happens ?

Thanks a lot

nnazzal
2009-06-29, 11:18 PM
The BTS will stop transmitting the BCCH in case of transmission line failure like Microwave or E1/T1 because the BTS apply the instruction coming from BSC, so the TS that handle the BCCH and/or TCH’s will have the regulations from BSC i.e. power control, DTX, …, and you can check the radio when the transmission link disconnected between BSC-BTS to check the BCCH, you will not find that BCCH in the air.

hassen
2009-06-29, 11:41 PM
hi
if the link between BTS and BSC goes down but bts still on yes you can receive bcch
but no traffic.

br hassen

nnazzal
2009-06-30, 02:18 AM
I have a question ;

where the Hop frequesncies stored, and how it is going with the scequence? is it inside the BTS of it is comming from the BSC algorithems?

for the BCCH, is it stored inside the BTS? if yes in which part of the BTS, in the TRU? i believe the BTS cannot know it's BCCH if the link with the BSC are disconnected, else you will find the BCCH in the drive test while the site is in NOOP status "Not Operational".

i am right?

hassen
2009-06-30, 02:25 AM
hi

you are right but if you restart bts and transmission link are down of course bts loses
its frequenies stored inside DXU.

br hassen

atese
2009-06-30, 03:48 AM
Hi.

in Nokia system the BCCH continues in broadcasting but the mobile can´t get access due to fail in all the transmission link.

I have notice that after this kind of fail, once the transmission is on, the outgoing HO failure increassed.

Any information about this fail in the handovers?

nnazzal
2009-06-30, 04:16 AM
In Ericsson BTS's while i am in a drive test i noteced that if we have transmission problems i.e. some sites have the link failed, no BCCH in the Drive test list, actually i believe that if the BTS failed to update the uplink measuremetns to the BSC it stops transmitting in the downlink.

if any one have a document to prove the status of the BTS while the transmission is off, please share.

Any way, please add me more reputation i have no enough reputation.

Thanks

atese
2009-06-30, 04:29 AM
Hi all,

I am asking what happen if the link between BTS and BSC goes down (for example as in the case of hardware faults for microwave link ).

In this case the BTS:
1) continue to transmit the BCCH or
2) BTS stop the BCCH transmission

In the first case 1 above the users receive a signal (bcch) and could try to make a call that will be rejected (for sdcch block)?

In second case simply the users will not have coverage ( if we assume that there are not other useful cells in the area)

Who can explain what really happens ?

Thanks a lot

Probably in ericsson there is a flag in the transmission, when this flag is interrumped the BTS noticed that the link is broken and turn it off the TRX´s.

I´ll check in my papers to confirm that and let you know

dexterhaba
2009-07-02, 06:01 PM
hi
if the link between BTS and BSC goes down but bts still on yes you can receive bcch
but no traffic.

br hassen

You can still recieve traffic in handover.:p