Major Airtel 4G issue: No internet while on voice call

[formfollowsfunction]

Airtel is using CSFB (circuit switched fall back) for voice calls.

When the mobile recieves a call, it switches to 3G/2G. LTE being a pure packet switched network cannot deal with calls except when using VoLTE and therefore fallback to 2G/3G is needed in absence of VoLTE.

Nice document by Ericsson detailing CSFB: Source


If it falls back to 3G, data can be used. If it falls back to 2G, data cannot be used.

In my case it does show on the phone that it has fallen back to 3G (the icon changes from LTE to 3G) as soon as I start a voice call when on LTE but internet actually doesn't work.

 

[x720]

Should not be happening. Issue with the sim card perhaps?

 

[formfollowsfunction]

Should not be happening. Issue with the sim card perhaps?

Did that too 🙁 replaced with a new Sim and still the same issue

 

[formfollowsfunction]

Interesting Article. This particular line was of special interest in this scenario:
“We have found technical evidence showing that operators are loading high-end data customers on an exclusive network. The telecom regulator has been requested to monitor the network regularly,” a top official in the Telecom Commission, the policy-making arm of the communications ministry, told HT.

An official in the Telecom Enforcement, Resource and Monitoring (TERM) Cells alleged that Airtel was offering 4G operations using Bharti Infratel’s towers and not through Indus towers, which carries its majority of voice and 3G data traffic.

Telecom regulator frets that 4G may go the call drop way

 

[x720]

Shouldn't cause an issue for you. While 4G might be served from a Bharti Infra site, if an indus 3G site is nearby, it will fall back to that!

 

[kanagadeepan]

Even with NO indus tower in sight, it will NOT be a problem.. If Airtel is using its own tower for 4G, why NOT for 3G also in the same tower?? Fallback is very important for 4G operators who are using legacy tech for voice calls...

 

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[dilipr]

Voice call quality is very bad... The other person won't be able to hear anything...