What is CSFB call flow?
What is CSFB call flow?
LTE to 3G UMTS CSFB call flow Describes the complete flow of circuit switched fallback from an LTE network to UMTS. You can click on most messages in the flow to reveal full details about individual messages.
What is difference between CSFB and VoLTE?
CSFB vs VoLTE CSFB (Circuit Switch Fallback) is a technology that supports voice and SMS services in 4G networks using the 2G/3G systems. VoLTE (Voice over LTE), on the other hand, means that a call is made through a 4G network (Making calls over IP).
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 LTE call flow?
With Long Term Evolution (LTE) comes a myriad of new and exciting attributes. One of these is the LTE call flow itself. In fact, call flow and signaling is unique for LTE, and is driven by 3GPP standards. Call flow is how signaling and sessions are created across an LTE network.
Why is CSFB required?
LTE is an all-IP technology and therefore cannot transport switched services such as voice or SMS, so CSFB is needed. When an LTE device is used to make or receive a voice call or SMS, the device “falls back” to the 3G or 2G network to complete the call or to deliver the SMS text message.
Is LTE packet switched or circuit switched?
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.
What is X2 handover in LTE?
eNodeBs in LTE are interconnected with the X2 interface. If two eNodeBs are served by the same MME, handover from the source to the target eNodeB will take place over the X2 interface.
What is LTE service request?
A Service Request is a procedure an UE executes when it is in Idle mode and needs to establish the bearers to send data or it needs to send signaling to the MME. The UE Triggered Service Request procedure is outlined in Figure 17.8.
What happens when a user performs a voice call from an LTE 4g network volte?
2.4. This message is forwarded to the UE, which is still connected to the LTE network. If the user accepts the call, it sends an SRM (Service Request Message) to the MME. The then MME notifies the eNodeB to transfer the UE for the legacy network, and the eNodeB then decide the best network for the UE to make the call.
How does LTE call work?
The phone remains in the 4G/LTE network during voice calls. You can use 4G/LTE data services, such as web surfing and tethering, while simultaneously making and receiving calls. When calling over LTE, you don’t use extra data but call minutes. You pay for the voice call service, not the data you use.
What is call flow in Telecom?
Call flow describes the process by which a network routes a call to a mobile device. Even LTE devices still use 3G networks for most voice calls. 3G call flow is different in a GSM network than in a CDMA network.
How does CSFB work with LTE?
At CSFB scheme, whenever there is a demand for a new voice call, the LTE user is ‘backed’ for a CS legacy network, assuming that this provides an overlapping coverage. In other words, with CSFB, a voice call is never active in LTE, but in legacy networks.
What’s in a CSFB call flow?
Summary call flow that focuses on the interactions between 4G and 3G networks for establishing a circuit switched call. MME interactions in a CSFB call. MME interactions with MSC-VLR are covered as well. MSC role in LTE to 3G circuit switched fallback. eNodeB interactions in a CSFB call flow.
What is the fallback call flow in LTE Mt CS?
LTE MT CS Fallback Call Flow In case of MT call, our UE is registered and is in LTE network. It receives a CS service notification EPS mobility management message for an incoming call. The LTE network will redirect the UE to UMTS network to complete the call.
What is CS service notification message in LTE?
The LTE network will redirect the UE to UMTS network to complete the call. CS Service Notification message: This message is sent by the network when a paging request with CS call indicator was received via SGs for a UE, and a NAS signalling connection is already established for the UE.
