Ericsson RBS2000 GPRS » History » Revision 2
Revision 1 (laforge, 06/25/2016 02:11 PM) → Revision 2/9 (laforge, 06/25/2016 02:46 PM)
h1. Ericsson RBS2000 GPRS This page collects some information regarding Ericsson RBS2000 GPRS support. The fundamental difference between what we do so far (PCU co-located with BTS) and this architecture is that the PCU is co-located with the BSC! In order to have (E)GPRS support using RBS2000, we need to solve the following parts: * configuration / activation of timeslots using OML2000 / RSL? * ensuring that GPRS related SI, particularly SI13 are broadcast via BCCH * implementation of PCU TRAU frame format and converter between osmo-pcu PHY interface and them ** 16k sub-slot and 64k slot formats ** associated PCU SYNC protocol ** all various coding schemes * paging coordination between BSC and PCU h2. PDCH timeslot configuration It seems that in OM2000 all TCH (/F, /H, PDCH) are configued with a Combination "8", and no differentiation is made The actual activation of the channel is expected via RSL. So it's analogous to a RSL CHAN ACT for TCH/H or TCH/F, but we also do this for a PDCH. In order to do so, we send a RSL CHAN ACT with Channel Number 0b11000 + the timeslot number. Deactivation works the same way. h2. GPRS RACH requests The BSC must identify the GPRS RACH requests (similar to osmo-bts currently) and pass them into the PCU. This could be done using the same pcu socket interface that already exists. h2. GPRS paging Thre's a RSL "Packet Paging Indication IE" (IEI = 0xF3) that the BSC can include when sending a paging request to the BTS. It's currently not clear what this is used for and why it is required. h2. TRAU frames
