Hi,
At first you have to calculate the TS no. for E1
1. TS needed for BCCH
2. TS needed for SDCCH/site
3. TS needed for TCH/site
4. TS needed for PDCH/site
5. TS needed for LAPD/site
6. TS needed for EDGE rate/site (eg. if you use MCS3-MCS6, then you need at least 2 TS)
7. Multiplex mode (4:1 0r 2:1)
Divide by the 31 (i think you know it)
You will get the E1 number/site.
Thanks