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yep… hsn = 6 or 40, it is pseudo random. so by definition, you can’t know what sequence of frequencies it will produce (random). But you know that HSN = 40 and HSN = 6 will be different. That’s all you need to know, operationally speaking, so there will be know collision.
Now, if you want to program your own BTS and your own frequency hopping module, yeah, you’ll need to know 🙂
Pix
Hi all,
Dear Yen you said :
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so, HSN =0, means cyclic hopping (no hopping, generally BCCH carrier)
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As i know cyclic hopping doesn’t mean no hopping but hopping between frequencies in the sequence with the same order each time. BCCH carrier should be a unique frequency and there is no hopping..!
Any one have more details plz
best regardsyes, you are absolutely right !
1- HSN = 0 means a cyclic repetition of the pool of frequencies
2- there is absolutely no SFH hopping on the TRX that carries the BCCH timeslot. (there can be BBH hopping, but in this case, HSN is not used)
Erkan,
Were you able to get an answer for your last question? If yes, can you please share with us?Borat
If HSN is the pseduo random sequence of TCH freq hopping, then what is the use of MAIO STEP?
MAIO is applied to same timeslot of different TRX (belonging to a same cell). For instance, each timeslot #3 will have a different MAIO, because they’re using the same HSN.
If all timeslot #3 have the same HSN (=sequence), they need to start their sequence at different frequencies, so they don’t run the same “pseuo random” sequence at the same moment. The MAIO will “offset” the sequence for each timeslot.
The “pseudo random” property means it will perform a sequence that looks random, but that in fact is not : the sequence of frequencies is fixed, and will keep repeating itself after one run.
Hi all .. I got a lil confusion on maio, can anyone please tell me when one trx has same MAIO then is it same for all 8 time slots of one trx.
yes it is same for all timeslots of that particular trx.
lotfi
i am agree with you
as i know about HSN AND HOPPING becase we have 2 channel group ,
channel group one which assign for BCCH carrier and hopping is off
and channel group two which assign fro TCH channel and hopping is on for thathello all,i am a beginer in GSM technology.can any please describe me the difference between Synthesized hopping and baseband hopping.
hello majba,
synthesized hopping :
all TRX except BCCH TRX will hop over a list of frequencies (= frequency hopping sequence). You can put as many frequencies as you want in the list (up to more than 30 usually).
Only the BCCH TRX requires a fixed frequency (bcch frequency that shouldn’t be included in the FHS !).baseband hopping :
All TRX can hop, but the list of frequencies is limited to the number of TRX in the cell. For instance, if you have 4 TRX, the amount of frequencies will be 4. Then, like a round robin mechanism, each TRX will use, for each TDMA frame, one of those four frequencies.
Only the 1st timeslot of the BCCH TRX cannot hop.
Each other timeslot can hop.
Everytime a timeslot uses the BCCH frequency, it cannot use dowlink power control.
Hope it helps,
Pix
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