[veeresh]

hi, telecom engineer

i wanna to know in 1 trx how many frames are there.

2. what is concept of sddch & tch drop
3. confusing me with 26 0r 51 multi frames

[jood]

1)SDCCH.> signaling drop
TCH.> traffic channel drop.
2)multi frame of 51 frames for signaling channel.
multi frame of 26 frames for traffic channel.

[suvendu]

hi,
i have a confusion about the activities of MOBILE just after the switch on…
means what are the procedureit go through for
1. PLMN selection
2. Cell selection
GSM 3.22 rec says that MS will first select PLMN and then suitable cell though logically its right but howcome an MS will select PLMN before camping on a cell .
also their is a restriction of scanning 30 RF channel for GSM so which 30 channel it will select?
if u clarify this whole proccedure that will be great help for me.
regards
suvendu

[In-building solutions prsntatn]

Dear All,

Who ever wanted to know about In-building solutions in a GSM/ CDMA operators please refer to the below site. It gives you the best understanding.

http://www.rfcafe.com/references/articles/articles.htm

[jood]

Hi suvendu
Attempt to access the home PLMN(broadcasted at BCCH) are performed as specified
bellow:
1 The periodic attempts are only performed in automatic mode
when the MS is roaming in its home country.
2 After power on, a period of at least n minutes and at most T
minutes is elapsed before the first attempt is made.
3 The MS makes an attempt if it is on the visiting PLMN at
time T after the last attempt.
4 Periodic attempts are only to be performed by the MS while
in idle mode.
5 If the home PLMN is not found, the MS remains on the
visiting PLMN

[suvendu]

Dear mr Jood,
my confiusion is regarding the process by which a MS search for network just after switch on..
so pls tell me those process…
means when it will scan forBCCH etc

[jood]

This is an aproaching process:
#Scan 124 RF channels and measure
signal strength for 3-5 seconds
#Tune to the RF channel with the highest
received average signal strength
#Determine if it is a BCCH carrier by searching for frequency correction bursts.
#Is it a BCCH carrier? The MS shall attempt to synchronize to This carrier and read BCCH info
#Is it the wanted PLMN?
#Is the cell barred for access?
#Is C1 > 0?
#Camp on the cell
IF THE ONE OF THIS STAGES NOT ACCOMPLISHED THE MOBILE WILL TUNE AGAIN AT ANOTHER STRONGE FREQUENCY.

[koko]

what does common bcch means and what is their funtion?
How to use debugger command(ZDDS)?

[SUVENDU]

DEAR MR JOOD,
WHEATHER A CELL IS BARRED OR NOT AND C1>0 THESE TWO INFO FOR A SELECTED CELL CAN BE OBTAINED JUST READING THE BCCH INFO (SYS INFO TYPE1,TYPE2)ONLY.WHERE AS IF THAT MS HAS NO PRIOR KNOWLEDGE ABOUT PLMN THEN WANTED PLMN CAN BE SELECTED ONLY AFTER SENDING THE DTAP REQUEST MESSSEGE TO BTS …IF I AM WRON THEN HOW AN MS WILL KNWO WHICH ONE ITS WANTED PLMN?

IF YES THEN FOR A GIVEN AREA WHERE SAY THREE PLMNS ARE PRESENT AND IF ONE MS SWITCH ON IN A PLACE WHERE ALL ARE PRESENT AND LET ONE OF THE PLMN IS HPLMN THEN IF MS IS SWITCHED ON THEN IS IT POSSIBLE THAT IT FOUND FIRST TWO STRONGEST SIGNAL OF OTHER TWO PLMN AND WHEN THAT MS TRY TO ACCESS FIRST TWO ,BECAUSE OF THOSE PLMN DENIED TO ACCESS IT WILL TRY FOR 3RD ONE WHICH IS SAY HPLMN , ITS REQUEST IS ACCECEPTED.
IS THIS STATEMENT IS TRUE IF NOT PLS TEL ME THE CORRECT STEPS IN THIS SINARIO…

[jood]

Hi SUVENDU
YOU RIGHT ,BUT I think it depend on preferred algorithm by vendor, But the major issue is that the MS has ability to search first on the (last registered OR home registered) PLMN (MCC, MNC) & this is ( According to PLMN list stored on SIM), so it made some kind of priority to search first for HPLMN, no matter of where the PLMN detection stage on algorithm flowchart, if it not HPLMN it will rejected & searching cycle start again. & thus by some ranking after unavailability of HPLMN the MS trying to roam on the next ranked PLMN. (PLMNs with SS > -85 dBm in random order)according to the registered list on SIM.
But note that there is not cell selection & camping before (PLMN selection)
BR

[Boko]

Also the MS checks periodically for Home PLMN (Prefered PLMN)

[suvendu]

In a place where there is no HPLMN,if a SIM as has no list of preferred network( in case of our Network)then how an MS will ranked other PLMNs ?
(what is the significance of SS>-85dbm)
tell me whether list of registerde network is samen as list of preffered network?

[suvendu]

again i hard that their is a restriction about no of Rf channel to be search.. when this things come into play?
(i.e 30 rf channel for GSM
40 for DCS)
pls explain

[Vijay]

Hi
shekar.pk@gmail.com
Shekar i think this bit rate is cal. from BT(bandwidth time) product 0.3 in Gmsk.

[Vijay]

Hi M.Thyagarajan
Can u plz focus on the c/i ratio calculation in case of hopping trx??

[Author]

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