EDGE Low DL Throughput

Thanks Master optimizer 😉
the problem occur all cell( ALU B9 )but sometime data thr > 180 kbit/s (static test)

MAX MCS = 9
GPRS HIGH LOAD = 80%
cell in the BTS = 3
MAX TBF PER SPDCH (UL & DL)= 5
MAX PDCH PER TBF = 5
Why only 2 Extra timeslots ? = no budget for 2 abis 🙁

could u pls recommend parameter setting and extra ts

Cheers,
KB

KB, no problem 🙂
if you can’t work on your Abis capacity.. mmm…

BTS config = 4/4/4 ?
that’s (i assume) 3 BCCH + 6 SDCCH
so you have 9 bonus nibbles + 8 extra nibbles… that’s a total of 14 extra nibbles.

Imagine: one MS, with 4 PDCH at MCS-9. It will use 4 x 4.5 nibbles = 18 nibbles.

it will use its 4 basic nibbles + 12 extra nibbles.

All extra nibbles are used up by only one MS !!!
Since they are a lot of GPRS signallings (Attach, PDP context, RA update), many MS’s will require capacity… And therefore there won’t be enough even for the one MS that needs 4PDCH at MCS 9.

Conclusion: you must add extra TS. If you can’t, then the ONLY solution is to reduce TCH capacity. You can do it this way:

MAX PDCH HIGH LOAD = 5 … 7 … 8
GPRS HIGH LOAD = 85% … 90%

Start with values at the left, then try the values at the right. Check if you have improvements, step by step. Check your TCH congestion.

If your BTS is 4/4/4, you should have more than 2 extra abis nibbles left… I cant remember exactly, but it should be 5 or 6, no ?

Finally, check your GPRS indicators. You can see how much Abis nibbles are busy or free, how many PDCH are allocated in the cell, at busy hour, etc. They will really help you to understand what is limiting your TBF throughput.

Krish,
ooooch… i’m sorry, it’s really hard to explain it on a forum.

I can only tell you that the names of those parameters are quite self-explanatory. And unfortunately, if you don’t understand them, it means you need some fundamentals trainings about GPRS Alcatel. I’m not being arrogant (for once ?), because it’s really a difficult topic.

That’s why 3G is so successful. GPRS was too complicated to understand :))

If we got 2 abis,the current extra ts = 2 .Avg TRX/cell in urban = 5.could u pls recommend no.of extra ts for hi-speed throughput

Thank you in advance
cheers,

KB

Hi pix,

thanks for ur reply.

hey i want to understand only this term if u can

(1) dl edge and gprs thrput per tbf like value 75,200,121= it indicates data volume or speed?

(2) tbf success ratio per tbf= it indicates per ms ?

Thanks Master

at here have team plan for low Throughput 😉

could u pls explain 4.5 nibbles at MCS9

Hi guys, gone through this but I need to get more understanding. What if i have a case of 2cells i.e 4/4 Trx on cells 1 & 2. With (1BCCH + 2SDCCH) on Trx1 of Cell 1 and (1BCCH + 1SDCCH) on Trx1 of Cell2. How many Basic, Bonus and Extra Nibbles do I require? Also what are the total Number of Abis TS on [Basic, Bonus & Extra Nibbles]?