- This topic has 19 replies, 1 voice, and was last updated 13 years, 9 months ago by Logic Thinker.
20th June 2007 at 11:27 #47885akefaGuest
Is it right to say that the floors from the 7th and above are hard to be covered by GSM without problems? Is right the only way is indoor cell?20th June 2007 at 16:06 #47886nutanGuest
this is very good question but indoor cell is not the solution because first of all it depends on the terrane. definitly more than 3 or 4 sites will be serving to the higher floors with good coverage.so if u put indoor cell it will not be the dominant one. the only solution is to optimize all the serving sites and make one site dominant to that floor.20th June 2007 at 17:26 #47887pixGuest
yes, the problem in higher floors is not the rxlev, but rather the interferences : multiple sites will be received up there, it is almost certain that they will interfere with each other (since the frequency planning can’t take into account this situation : it will put too much constraints on finding a good frequency planning!)
putting an indoor site is a good solution only if you ensure the indoor cell is uing a clean frequency. Best way : provide a frequency band dedicated for indoor cells.
regards21st June 2007 at 09:15 #47888nutanGuest
you are right but if we provide a frequency band to indoor cell then it will be too dificult to plan. if we have 10 such high rise buildings in a same area then how can we give different frequency band for every building?
we have limited number of freqencies so better we optimize the sites in such a way to decrease the interference.21st June 2007 at 11:48 #47889PixGuest
No, you define one frequency band for all the micro cells. For instance 4 frequencies that will be used only by micro cells.
One micro cell in one building will not interfere with another micro cell in another building..
But as said earlier : it’s all up to you and your network design… there is not one solution for all networks 🙂
Regards,21st June 2007 at 21:38 #47890akefaGuest
one of the main problems in the high places is the bcch interferenc that may make the MS’s seem to be switched off while the rxlev is within -50’s db !
as nutan said the indoor will solve the case only if it is the dominant. How many db differnce needed?
I think Pix idea regarding specifying a certain band for the indoor has no effect unless those indoor sites are the dominants in their places. Am I wrong?22nd June 2007 at 07:45 #47891PixGuest
When you are having an indoor site, you increase its cell reselect offset so it becomes the best server in the area.22nd June 2007 at 08:24 #47892akefaGuest
Good mornning Pix
Why dont an engineer increase the offset of one of the main serving sites. Isnt it more economic solution than installation of a new indoor site? Especially when we have alot of high buildings
best regards22nd June 2007 at 10:47 #47893nutanGuest
The indoor cell idea by Pix is confusing.if we place the indoor cell with a freqency band which has a Rx lev in 50’s or 60’s dbm. There are already some serving sites to that area which have good Rxlev in 60’s. Whats the guarenty that the MS will always latch to the indoor cell? If the MS is near the window or the open area in that building it may latch to the others sites and it might cause call drop or other problems.Indoor cells are good to implement in those buildings where there is coverage problem.22nd June 2007 at 10:50 #47894nutanGuest
can you please tell which offset you are talking about.
there are different kind of offset values.22nd June 2007 at 11:47 #47895PixGuest
increasing the CRO of one outdoor cell is good idea, but :
1. it means you’ll increase this outdoor cell’s coverage everywhere, not only in the building.
2. you need clean frequencies in this outdoor cell, in the higher floors.
Read the start of the thread : we have good coverage in higher floors, but probably interferences… my message was referring to the past messages. By itself, it sure sounds confusing 🙂 Sorry about that 🙂
Regards,22nd June 2007 at 20:02 #47896ADGuest
i think Cro solution is typically made for the indoor cells. The penalty time inhibits the fast moving vehicles to camp on the micro cells whereas the stationary users can camp on the micro cell.
Usually we donot change the parameters of a macxro cell because it is going to affect a larger area.22nd June 2007 at 20:34 #47897akefaGuest
Do you mean that an indoor macro in the 7th floor and above will affect outside?!
Outdoor cells will have line of sight (LOS) path to the high places and this is why they are strong but indoor cells in the high building will not affect outside.
BR23rd June 2007 at 06:44 #47898IBSGuest
IF U GETTTING GOOD COVERAGE SAY -50dbm ON HIGH RISE BUILIND THEN U CAN GO WITH BOOSTER SITE-WHICH MEANS ONE KIND OF IBS-REPEATER THAT MENAS U USE SOME SIGNAL FRM THE NEARBY STRONGEST SERVER SITE,IT CAN HELP U REDUCE UR PROBLEM BUT IT IS IN LIMITED AREA ONLY SO IF IT IS BIG PREMISES OR BIG AREA OF THE OFFICE U SHOULD GO FOR THE NEW SITE OF INDOOR BUILIND SITE WITH TIEGHT FREQ PLANNING.24th June 2007 at 09:24 #47899nutanGuest
I dont know why everyone is giving different kind of solution.
Lets go for futher discussion practically.
for example in 8rth floor the serving sites are
A- rxlev- -55dbm(average)
B- rxlev- -62dbm
C- rxlev- -68dbm
D- rxlev- -75dbm
E- rxlev- -50dbm
indoor site with dedicated frequency band- -45dbm.
now please tell me you r user in 8rth floor. to which cell or sector your mobile will latch and why? Will it always latch with the indoor one? What difference it will make if i give different values of C1 and C2 to every site or sector or what value i should give to indoor cell?