A couple of days ago I wrote about the slow startup time of UMTS during mobile web browsing when the air interface connection is in disconnected state. Looks like my idea of establishing radio bearers early for example when unlocking the phone is not necessary as a couple of enhancements are already foreseen to address this issue:
The first feature is the Cell- and URA-PCH Radio Resource Control (RRC) states. Already defined in the very early stages of the UMTS development they are still not used by most operators today. The major difference to going to RRC disconnected during a prolonged time of inactivity is that all logical radio bearers remain allocated and also the logical signaling link from the Radio Network Controller to the SGSN in the core network remains in place. So instead of going through the procedures for RRC establishment, authentication, ciphering, radio bearer setup and radio bearer reconfiguration for high speed, the mobile device simply goes back to Cell-FACH state by sending a data packet. And from there, a radio bearer reconfiguration takes the link back to the high speed channels.
So instead of over two seconds, the procedure takes from the disconnected state today, the time necessary to get out of Cell- or URA-PCH state to the high speed channel should be similar to the time it takes from Cell-FACH to high speed today, which is less than a second. That's very close to the times already achieved with the good old GPRS/EDGE air interface. There might be an impact on power consumption with the Cell- and URA-PCH states. However, like in idle state, only the paging channel needs to be observed so this is likely to be a small trade-off.
The second feature is the Enhanced Cell-FACH state that is part of the Continuous Packet Connectivity feature which I've reported on here, here and here. That should reduce the time even further as the radio connection doesn't have to make a detour over a dedicated channel.
All very nice, now it just has to come!