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BCCH Failure

Viewing 15 posts - 46 through 60 (of 84 total)
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• #36658
M.Thyagarajan
Guest

Hey ,

you are confusing between what ts0 is and what i have mentioned , the time slots are mapped into the multiframe structure that both the MS and the BTS understand.You have to go to the frame structure of GSM to understand this better.

Obviously we will have sets of channels for BCCH and TCH the BCCH should not be in Hopping.

These are steps that are called related to RF Desigh based on these results you will choose the number and the location of the sites to be planned then we do the survey and go forward in this /

#36659
sam
Guest

thanks mr.thyagarajan. one more clarification: In one of the document relating GSM planning i found one question as follow:
Calculate number of site required to cover 1,000 sqkm area, assuming each site has 3-sect cell each covering 3km?

Soln was given as follow:
Coverage per site= k * 3^2=17.55
where k=1.95
Total number sites=1000/17.55=57app

I didnt understood what is k here and is this sol correct. if correct pls let me know what are parameters assumed in this sol.

#36660
M.Thyagarajan
Guest

The formula mentioned is the theortical way to caliculate the coverage area of a site , but this is not the way to plan for sites as the coverage area depends on the level u want to acheive and the cluter of the area ok.

#36661
jood
Guest

hi sam
assume that the coverage area of cell have radious =R
& the distance between site to site is= D
& the number of sites youcan put on all your freq=(reuse pattern)
Reuse pattern may be 4 sites, 3, or 7 sites as you like.so the num of site in reuse pattern is K or (reuse factor). which allow you to reuse the freqs in another pattern. so you plan small reuse or large.
D= squ Root(3KR).

#36662
M.Thyagarajan
Guest

hey sam and jood,

the formula that jood mention here is for the site to site distance to avoid any interference as u can see d proportional to reuse pattern , if the reuse is less the distance has to be reduced ,.

But u must have capacity of the site under consideration to i,e u might have a D very large but the sites would get congested ,

For me it has to be a compromise of capacity + coverage range u should max erl per sq Km of the site to get the best quality of network

#36663
jood
Guest

hi M.Thyagarajan & sam
Notice that the reuse pattern is affected by how much capacity you would like to offer according to your limmited freq spectrum.
# small reuse=>> high capacity & high interference risk(need to use some interference compat technics)
# large reuse=>> low capacity & low interference.
…The three main issues to define reuse pattern is (CAPACITY, COVERAGE & ANTENNA HEIGHT).

#36664
sam
Guest

thanks to jood & M.T who took out there time to answer my question.

#36665
sam
Guest

Is there anyway to know what are the equipments,modules,digital cards,make, connection diagram used in BTS.Pls let me know if there is any website for this

How many TRX we can have in 1 BTS/BSC considering hardware in BTS, like which card supports how many TRX and how many cards we can have(min & Max).

#36666
jood
Guest

Hi sam
generally:
BTS contain three main level (as cards).
1) Antenna coupling level, diff name for it from diff vendor(ANT or CDU……) but mainly it contain (tx combiner+duplexer tx/rx+ rx spliter+ rx,tx filter+ LNA+VSWR detection)
2) TRX level (coder & decoder+channel coding & decoding + VSWR supervission + modulation schame (GMSK or 8PSK)and each trx contain 8Ts)each module is integrated with differ feature(HR,FR,EFR,FH,diversity & some ciphering algorithm)& also handling radio signaling link protocol.
3) Base station function level (it mainly performed by central prosesing unit(SUMA or DXU ….as the vendor define)SO it Generating the clock (internal or syncoronise with external clock), Hndling A-bis TX, Ensuring O&M, Handling OML,Qmux(transimission protocol..& some else control function as the vendor.
# the configuration of TRX may extended up to 12/12/12 for each sectors.

#36667
sam
Guest

thanks a lot jood. ur explanation was really beautiful.

Are document relating each level available on net?
regards,
sam.

#36668
monem
Guest

Hi JD
It is important to dimension the OL subcell so it will be
congested before the UL cell since traffic can “spill
over” from the OL subcell to the UL subcell.
if the SCLD active
you should adjust LOL+ LOLHYST & TAOL+ TAOLHYST.
then you should fine tune the SCLDUL & SCLDLL which they can inhipit the HO from OL to UL when there is congestion.

#36669
jood
Guest

Hi sam
declare your Email to send you what I can(according to my vendor).
BUT,,About suppoting web??? I dont know …. you can browse for them.

#36670
sam
Guest

hi jood,

thanks a lot for ur effort. my email id is sammy123t@yahoo.com.

regards,
sam

#36671
…….
Guest

Hi JD
It is important to dimension the OL subcell so it will be
congested before the UL cell since traffic can “spill
over” from the OL subcell to the UL subcell.
if the SCLD active
you should adjust LOL+ LOLHYST & TAOL+ TAOLHYST.
then you should fine tune the SCLDUL & SCLDLL which they can inhipit the HO from OL to UL when there is congestion.

#36672
sam
Guest