Had enough of CSFB call set up delays, delays in returning to LTE after voice call termination, additional signalling due to routing/location/tracking area updates?
Time to deploy VoLTE!
Here is my checklist to get things started..
1. An IMS network
2. UEs that support VoLTE
3. Support for QCI 1 (voice) and 5 (IMS signalling)
4. Support of QoS on your LTE network to prioritise QCI 1 & 5 and pre-empt other QCIs if needed
5. Semi-persistent scheduling so you don't run out of PDCCH capacity
6. Support for RoHC
7. A dropped call rate on LTE equal or better than the CS dropped call rate on the legacy network
8. Support for RRC Re-establishment (intra & inter eNodeB) to help with the above
10. Support for TTI bundling to improve cell edge performance
11. If your LTE coverage is not as good as the legacy network then SRVCC support to handover calls from LTE VoLTE to the legacy CS domain
12. Upgrade legacy MSCs to connect to IMS
13. Upgrade legacy MSCs to connect to MME via Sv interface
14. UE battery life in LTE equal or better than 3G
Easy :)
Hi, not related to this particular post, but just want to say that I found your blog very recently, and it is super useful. Thanks.
ReplyDeleteAfter 12 & 13, definitely a few more with "make sure your existing service layer system xyz is upgraded to be IMS capable".
ReplyDeleteThis is keeping me in work at for the year or two....
You can add to the list:
ReplyDelete* A PCRF with rx interface to the CSCF.
* Gx interface between PGW and PCRF
* Dedicated bearers creation support with GBR end to end.
Dudi
You don't just need "support" for VoLTE in handsets, but also all the other media-engine paraphernalia like acoustic echo-cancellation & packet-loss concealment. Also ideally some clever Skype-type user interface approach to cover up for (inevitable) audio deficiencies.
ReplyDeleteFor any form of VoIP, "cure" for packet loss in software/codecs is at least as important as "prevention" in the network. QoS is only part of the answer.