ALU Drop Radio

Dear Paul,
This is a generic problem and not only ALU Specific.As pointed out by Pix earlier aswell….the best solution is to prevent overshooting by Hard Optimization(tilt/azimuth steering) and confine the coverage of the cells to their logical footprint 🙂

paul,

choosing 43dBm will not force the MS to emit stronger (they cannot exceed 33dBm, physically), but it will strongly impact your C1 and C2 criterion for reselection.
So keep it at 33dBm.

My solutions below intend to improve the coverage, not reduce it. I didn’t say to downtilt, but “adjust” the tilt. Perhaps you need to uptilt, or perhaps to downtilt, in order to increase the coverage in that area 🙂

regards
pix

paul,

6am here 🙂 i live at the intersection of belfast, madrid & luxembourg… take a guess !

yes, to improve coverage the only way is hard optim. Unless you forgot to declare the neighboring relationship with the best server that covers this area..? That would be the only possibility.

now, wait… there is one “soft” way to improve coverage:
frequency diversity : activate hopping with more than 4 hopping channels spaced by more than 1MHz each, and that will reduce the effects of fast fading. That’s the theory, now i’ve never measured the effect myself. I used to activate FH in remote area to enhance coverage, but in such area there is not much fast fading. Anyway, it’s still better than doing nothing. I could say I tried 🙂
regards
pix

Dear Pix,

Thanks for your response 🙂

Related to hopping channel, I want to share about our frequency planning in my network.

Exmple, FLP GSM

FLP 1×3
For BCCH : 107 – 124
Guarband : 106
For TCH: 88 – 105
Sect-1 88 91 94 97 100 103
Sect-2 89 92 95 98 101 104
Sect-3 90 93 96 99 102 105
MAIO Sect 1 : 0 2 4
MAIO Sect 2 : 1 3 5
MAIO Sect 3 : 0 2 4

Those are my network FLP planning.

What do you think? Is that frequency allocation secure enough from interference (MAIO)?

Then, what your sugestion (Activate MAIO Hopping more than 4 …), i haven’t tried it, but what I’ve tried was like this :

Cell A Sector -1 :
Old setting of MAIO : 0 2 4
OLD MAlist : 88, 91, 94, 97, 100, 103
New MAIO : 4 6 8
New MAList :88, 91, 94, 97, 100, 103, 107, 113, 119, 122

And that’s working! 🙂 I didn’t add MAIO up to 4 or more than 4, but added MAlist and changed the MAIO period only.

In your suggestion, we added new MAIO or change the MAIO with hopping channel more than 4. So how should I arrange the MAIO without adding the MALIST? If we set MAIO 0,2,3,4, then the hopping channel is too close (impact on interference). Any Idea brother Pix? Well, what’s your suggestion towards my network FLP allocation?

I would be grateful to discuss it with you and all experts in this forum 🙂

Best Regards,

Paul

How do we recognize Fast fading is happening in any network?

aks,

fast fading, rayleigh fading… google it. It is the cancellation of phases of a signal that travelled through multiple paths.

ALU,

good geographic skills !
FH was not activated everywhere : in remote area, the operator used NH.
FH is well known for helping with frequency planning & interference, but less known for its coverage enhancement properties. So in remote areas, I do’nt blame anyone for not activating FH.
On top of that, FH on a cell with 2 TRX sounds useless:
either BBH over 2 frequencies
or SFH on 1 TRX. But then the BCCH TRX doesn’t get the frequency diversity.

what do you think ?
pix

hi alu,

dfh is just a smart name for SFH when there is a little amount of trx in the cell, right ?
but doing sfh in a 2trx cell means the bcch freq is not hopping… Applying the sfh would “only” bring better rxlev during a call on 2nd trx. Which is of course a good thing anyway since most calls will be allocated on 2nd trx 🙂

Now, going even further : it means you need to have the SDCCH on the 2nd TRX too, to fully benefit from FH during the call setup. And since you must have a SDCCH ts on 1st TRX too, it means you need 2 SDCCH ts on such cell. (not really a problem) and by default, it is the sdcch on the last trx that is used preferably.

cheers
pix