SDCCH Drop and Block

[radio_network]

what's the cause for SDCCH drop and block. And what is the difference. How the stats are being pegged for this cause.
I am not able to define it clearly. Most often i m faced with this type of questions in interviews.
From my point of view cause for sdcch drop: BCCH inter and block: LAc border/planing
any more explanation pl.

[ghassen]

what's the cause for SDCCH drop and block. And what is the difference. How the stats are being pegged for this cause.
I am not able to define it clearly. Most often i m faced with this type of questions in interviews.
From my point of view cause for sdcch drop: BCCH inter and block: LAc border/planing
any more explanation pl.

check timer and other related parameter to SDCCH assignement that expire
T_MSRFPCI .....

[kais]

what's the cause for SDCCH drop and block. And what is the difference. How the stats are being pegged for this cause.
I am not able to define it clearly. Most often i m faced with this type of questions in interviews.
From my point of view cause for sdcch drop: BCCH inter and block: LAc border/planing
any more explanation pl.

SDCCH drop radio
Check if SDCCH dropped are coming from a radio problem.
Test if SDCCH dropped due to radio problem (SDCCH_drop_radio_ratio) represent more than 40% of all SDCCH dropped

1. SDCCH HO not activated
Check if handovers on SDCCH are activated.Test if handovers on SDCCH are DISABLE.
Activate handover on SDCCH and check for improvement. Reduce averaging window if necessary


2. TCH radio problem
Check if there is also TCH call drop coming from a radio (Call_drop_radio_rate) problem.
Test if call drop rate due to radio problem is higher than 3%.
A correlation may be made between the 2 problems, you should run a RNO diagnosis on TCH call drop for cell




if good apreciated : add thanks and reputation

[Khairul]

what's the cause for SDCCH drop and block. And what is the difference. How the stats are being pegged for this cause.
I am not able to define it clearly. Most often i m faced with this type of questions in interviews.
From my point of view cause for sdcch drop: BCCH inter and block: LAc border/planing
any more explanation pl.

Hello,
The cause of SDCCH drop are many, but the most common reason is due to RF reason during call setup and/or handover process. Other reason of drop is simply the Non RF related i.e the interfaces at Abis, A IF, transcoder, BSC, BTS and/or user action.
As of SDCCH Blocking, this is concerning the "accessibility" of MS compared to Drop literally means "retainability" thus check your dictionary to understand its differences.. caus of block is not enough channel to support user request.

Best regards,
Krule

[kais]

check timer and other related parameter to SDCCH assignement that expire
T_MSRFPCI .....

SDCCH drop HO case

Check if SDCCH dropped are coming from a handover problem.
Test if SDCCH dropped due to handover problem (SDCCH_drop_HO_ratio)represent more than 40% of all SDCCH dropped

1. TCH HO problem
Check if there is also TCH call drop coming from a handover problem.
Test if call drop rate due to handover problem (Call_drop_HO_rate) is higher than 3%.
Action:A correlation may be made between the 2 problems, you should run a RNO diagnosis on TCH call drop for cell


2. Standalone SDCCH HO problem

Check if there is no TCH call drop coming from a handover problem.

Action:Try to move SDCCH channels to a cleaner TRX-TS or disable handovers on SDCCH and check the impact on global SDCCH drop and particularly on SDCCH drop radio


add reputation if appreciated

[kais]

is there any comment

[lamhd_bk]

some reason for blocking or dropping SDDCH :

-increase in traffic requery expansion of SDDCH resource
-cell coverage too large, too many platom RACH
-poor location area border planing ( too many LA update )
-inapproriate to set timer in BSS database
-interference, causing SDDCH holding time to increase
- antena too hight
- HW problem...

some time in the A-bit interface have a broblem but I don't know about it, so i think that , if everyone have some experence in this interface, pls share us

[hakimgsm]

Dear all
Some docs are available in the following link: http://www.4shared.com/dir/19448940/...e/sharing.html

Thanks

[Shakeel_15]

Hi,

SDCCH Blocking and SD Drops is a common probem you face during the optimization process. But you can optimize it by making some checklists.

Ok Lets start.

.... First Check SDCCH Blocking, if exisits then add a TS for this.
........Also you can use dynamic SDs by tracing the SDCCH and TCH blocking trend.
.....Next the important thing that you have to check the SDCCH Distribution on a cell if all SDCCHs are defined on a single radio you have to homogeniously distribute them on radios and it will oprtimizing the signalling load and you will see good improvement in SDCCH Drops and also in many cases SDCCH mean holding time.
.....You also have to check the faulty radio if SDCCH are defined on that radio you have to shift them to other radio and also you have to replace the faulty trx.
.....You also have to check intereference to avoid consective TCH and SDCCH drops.
.....Also your abis link should be stable.
.....And please dont enable SDCCH Handover for this type of cases.
......Sometimes your BCCH radio degraded and you feel low RACH success rate and high SD Drop (SD on BCCH) rate you have to swap this with a good one or check if its ok with hard or soft reset.

Try it..

BR

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what's the cause for SDCCH drop and block. And what is the difference. How the stats are being pegged for this cause.
I am not able to define it clearly. Most often i m faced with this type of questions in interviews.
From my point of view cause for sdcch drop: BCCH inter and block: LAc border/planing
any more explanation pl.