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Hi everybody,
I am telecom technician and my boss told me that i have to implement Syn. Frequency hopping on our GSM network. Can anybody provide some files about FH?
Also I have a question, how must the TSC( Training Sequence Code) planned? any Idea?
Regardsyou dont have to plane TSC (defaut value)
Hi Colein,
Thanks for your quick response,
I am little confused with the term frequency load? In my network the max. BTSs is S888 and i have 11 frequencies for Synthesized frequency hopping therefore will it enough to use that number of frequencies or does it need more?
Regardsfor configuration 8/8/8 you need 3frequenceis BCCH, AND for hopping TCH you must use hopping frequency set more than your carriers on sector.
So to abtain acceptable result (9 frequency per sector plus one for BCCH => (9×3 + 3)= 30 freq.
BUT the more you use big hopping freq set,the better you get good signal quality.It depends on the reuse pattern you want to use.
If you go by 1*1 (1MAList for all your sectors), you need at lesat 44 frequencies for your hopping list.
If you go by 1*3 (1 MAList per sectors, 3 MAlist that are repeated on a site basis), you need 42 frequencies for your hopping list (14*3).Regards
hi yrrah
for 1*3 (1 MAList per sectors) it is good to use 14*3FHS, BUT 8*3 is also posible but the efficiency is low than 14*3 but accepted.Hi All,
Have you ever implement SFH for 4 sectors site and it has neighbor 3 sectors sites ? And how it performance.. ?
Thanks
santo
Hi areeba,
it depends on the number of hopping TRX you have.
If you want to avoid collison (co channel or adjacent channel), you need at least twice the number of hopping TRX. If you have less frequencies, you will face collision.
Your MAIO planning will be more difficult too.
If you have any info how to allocate 3*8MAlist if you have S888 sites, i would like to know.
I heard about a new planning strategy called “Ad Hoc” for SFH.
you allocate your frequencies list on a cell basis. The length of the MAList depends on the number of TRX you get.
I’m searching some informations about it, but it seems too hard to get anyone.Regards
yrrah
Yes in SFH its mandated to establish MAL twice or more than your TRX in sector.
BUT see that: the main idea of the hopping is to averaging the interference in all channel. SO as more as you add freq to MAL above the twice no of TRX per sector as you have better performance based on quality enhancement.
Cuz you deal here with (frequency selective fading). & any environment has a certain coherence fading (the BW between two frq which it high correlated for fading).
SO:
Rural: delay spread(low)===>coherence fading is high===>need large BW of MAL to deal with such fading seemed to be flat fading.
Urban: delay spread(medium)===>coherence is medium==>need medium MAL BW.
Dence urban: delay spread(high)-=>coherence is small==> need low BW MAL.
AND INDOOR: delay spread is tooo small==>coherence fading is tooo large (flat fading) ====> need tooooo large BW MAL to deal with such fading (not practical),For 8*3freq if you have S888 sites it will be:
MAlist= A(8), B(8), C(8).
SO you can use the following dimensioning:
SectorA ==> MAList(A+B)
SectorB ==>MAList(B+C)
SectorC ==>MAList(C+A)
But the orthognality performance with MAIO will be throug different algorithm.
BR…..Dear areeba,
can you explain why in indoor the delay spread is too small. On the other hand, what it is the diferent algorithm the for orthognality performance with MAIO?
the power delay profile of RX signal at in-door environment is too small compared with other environments
Colein,
How did you get 9 freq per sector plus 3 for BCCH? can you tell me those parameters? What I mean is what is the 9 freq and 3 frequencies.
thanks!!!
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