What is the CSFB in LTE?

Circuit Switched Fallback
Circuit Switched Fallback (CSFB), with the help of a global system for mobile communication (GSM) or another circuit-switched network, delivers voice and SMS services to LTE devices. The necessity for a Circuit Switch FallBack for the packet-based all-IP network, LTE, which cannot support circuit-switched calls.

How CSFB works in LTE?

LTE MT CS Fallback Call Flow The LTE network will redirect the UE to UMTS network to complete the call. In response to this the UE sends the Extend Service Request message. In this message it mention the service type as “mobile terminating CS fallback”. Also, it sets that the CSFB request is accepted by the UE.

How CSFB is triggered?

Triggers of CSFB (When to perform CSFB) v) UE is capable of VoLTE, ims PDN is established and UE is registered in CSCF, but Network notifies ‘VoLTE not supported’ in NAS message.

What is extended service request in LTE?

LTE: Extended Service Request Ø The EXTENEDED SERVICE REQUEST message is sent by the UE to the network to initiate a “CS fallback or 1xCS fallback call” or respond to an “MT CS fallback or 1xCS fallback” request from the network.

What is a CS call?

Circuit switching (CS): It is used for voice communication which requires dedicated connection between calling and called party to take care of latency requirements of real time voice calls.

What is EPS fall back?

EPS Fallback is a mobility trigger for improving voice KPI (Key Performance Indicator) which enables 5G phones to use NGC (Next Generation Core) with New Radio for all data traffic while allowing phones to switch to LTE (Long Term Evolution) EPC (Evolved Packet Core) for voice calls.

Does LTE use packet switching?

The LTE standard supports only packet switching with its all-IP network. Voice calls in GSM, UMTS and CDMA2000 are circuit switched, so with the adoption of LTE, carriers will have to re-engineer their voice call network.

Does LTE use circuit switching?

In LTE (4G) the entire network uses packet switching and has no capability for circuit switched network support. As a result, the voice and SMS services must be moved over to a packet switched network when using the LTE (4G) network. In addition to this, CSD is no longer supported and GPRS data must be used instead.

When does CSFB trigger in idle in LTE?

There are several variations in CS Fallback. (NOTE : All of these are based on the assumption that VoLTE is not supported) i) Somebody make a voice call to you when you are in . (CSFB is triggered by Paging message)

Which is part of CSFB feature does UE support?

As indicated earlier, SMS delivery via CS Domain is also defined as part of the CSFB feature. UE can utilize this feature after it has successfully attached itself to the CS domain. It should be noted that EPS has the option to support only the SMS feature and not the CSFB feature which redirect the UE to another RAT.

Which is an advantage of CSFB over IMS VoLTE?

The big advantage CSFB is that in the initial phase operators did not need to roll out IMS VoLTE. The precondition is the UE is registered to the LTE network. We do not have any VoLTE service available. So when the UE will originate the call, the network will ask the UE to move to 3G to initiate the call.

Is there a CS fallback in LTE network?

LTE is an all-IP network with no CS support. To support voice communication operators have many options. Let’s check briefly about the above options for voice communication. VoLTE is the true solution for voice communication over the all-IP LTE network.

What is the CSFB in LTE? Circuit Switched Fallback Circuit Switched Fallback (CSFB), with the help of a global system for mobile communication (GSM) or another circuit-switched network, delivers voice and SMS services to LTE devices. The necessity for a Circuit Switch FallBack for the packet-based all-IP network, LTE, which cannot support circuit-switched calls. How…