Sunday, August 1, 2010

Mandate CS Fallback

There is so much debate going on about voice technology that should be used over LTE. I have my view here. Before a proper voice technology is figured out, I would assume that CS fallback will become a mandatory feature on all LTE phones. Though VoLGA and IMS seem to be good solutions, but they don’t solve many other issues, like roaming for e.g.

Its obvious that LTE phones will support 3G/2G technologies. Also with release 8 SGSN’s coming in the packet handovers to 3G/2G technologies from LTE and vice versa would be smooth. This means LTE phones are already equipped with 3G/2G chipsets. If so then why cant  CS fallback be made mandatory?

Yes, agreed that to access a voice call one should be cut out of LTE. But at least I am able to make a voice call even if I am not in my home network. Analyzing how the voice call can disrupt the packet service for individual users can be a separate case study. For e.g corporate users are heavily dependent on emails. So if voice call lands on their mobile the LTE service will switched off for couple of minutes which is very acceptable for an email user. Rest may not be convinced, but it does solve the problem.

One more point is SMS. I heard that SMS is mandatory in Europe, that is if a user is roaming then the roaming charges(?) should be informed to the subscriber by an SMS. If that is the case the CS fall back does help with smooth delivery of SMS over Sgs interface. However this may not be a permanent solution. As the technologies mature we can find a better way to deal with voice and data co-existence without breaking each others connection. Untill then operators please give us CS fall back support and also do not mess up your networks with putting many additional nodes.

6 comments:

Edgar said...

But aren't there some problems with delivering SMS to legacy networks with CS fallback? Would you be willing to do a closer look at CS fallback and its strengths/weaknesses? I would very much appreciate it.

Santosh said...

Sure! I next few days.

Edgar said...

I would also love to know more about the SGs interface! The standards are pretty clear but according to some operators it doesn't work as well as it should.

Asimananda said...

Technologies like IMS address roaming issues as well...thus it should work fine with LTE, or is there any additional roadblock? Detailed study may help understand this.

Santosh said...

True, but how many operators support IMS right away?

Moto said...

specifications are only a guideline. i think ehrpd will address the roving between 2/3/4g networks. All the while, IMS is still available, so we will want to leverage the SIP AS as much as possible for voice services, unless, it cannot be reached, then we will need to use the CS network. did i simplify it too much? the vendor is going to have to meet the provider requirement, and i just dont see not having a failback option.