- This topic has 4 replies, 1 voice, and was last updated 10 years, 3 months ago by Tim.
2nd July 2009 at 15:33 #57707Tom FoxGuest
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.3rd July 2009 at 18:02 #57708PixGuest
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.
`ppix16th November 2009 at 05:36 #57709Muhammad AtifGuest
Thanks for your help.I want to know can you please tel me which standard deals with it which you have mentioned above .16th November 2009 at 13:54 #57710PixGuest
I have no idea. It’s certainly in the serie 44 or 45 of the 3GPP, look for BTS-BSC protocols (layer 3).
The Exorpixt.10th June 2010 at 08:42 #57711TimGuest
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?