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I am looking for information on the allocation of E1 timeslots for Abis.
I understand that TS0 is reserved for signalling. I understand that per TRX that two timeslots are reserved for voice/data and that each of these timeslots are composed of 16 kbit/s sub-channel. I understand that the remaining timeslots are allocated for signalling associated for the call(s) and for signalling associated with each cell (BCCH/RACH/FACH/PCH).
What is not clear to me is if these signalling timeslots are at 16 kbit/s or at 64 kbit/s?
Also, what is the relationship between the voice timeslots and the call signalling timeslots? Is it vendor specific? And what are typical relationships.
Thanks in advance,
Tom.
Hi Tom Fox,
Let’s call the “RSL” the logical channel for 1 TRX.
Let’s call the “TCH nibble” the 16kb/s sub-channel on the Abis.One TRX requires 8 TCH nibbles = 8 * 16 = 2 Abis timeslots. (because 1 Abis TS = 4 nibbles = 64kb/s)
Your question regarding the RSL:
1 TRX can require more or less signalling, depending if there are a lot of SDCCH traffic, or half rate traffic.
In normal conditions, 4 RSL are sharing 1 Abis timeslot (64kb/s). The sharing is not static : it is dynamic. Each RSL could sometimes use the full 64kb/s, if the 3 others are idle… (it’s an example)If RSL is highly loaded, you could decide to share only 2 RSL on the same TS.
So typical RSL usage is 16kb/s in average. Could be up to 32kb/s in special case.
Cheers,
`ppixHi Pix
Thanks for your help.I want to know can you please tel me which standard deals with it which you have mentioned above .Atif,
I have no idea. It’s certainly in the serie 44 or 45 of the 3GPP, look for BTS-BSC protocols (layer 3).
Cheers,
The Exorpixt.The explanation given is very good. My question is;
What is the loading for SDCCH traffic on RSL and that of TCHF/H? Is it quantifiable?
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