top button
Flag Notify
    Connect to us
      Facebook Login
      Site Registration

Facebook Login
Site Registration

Can someone share the call flow for SMS over LTE(IMS)?

+2 votes
Can someone share the call flow for SMS over LTE(IMS)?
posted Aug 20, 2015 by Sandeep Otari

Share this question
Facebook Share Button Twitter Share Button LinkedIn Share Button
I don't remember it exactly.

However you can find it on for sure with good explanation.

Peeyush Sharma

2 Answers

0 votes

There are two main ways by which SMS can be delivered over LTE system.
• SMS Over SGs: Here LTE UE device sends and retrieves CS(Circuit Switched) based SMS messages.
• SMS Over IP: Here LTE UE device sends and retrieves SIP PS(Packet Switched) based SMS messages.

SMS over SGs transfer the messages between MSC and MME and transports the messages over LTE system using SGs interface. In this type the LTE UE does not fall back to legacy cellular systems such as GSM or CDMA. Existing roaming conditions will be reused in this type of SMS over LTE.

In SMS over IP mode, SIP based SMSs are carried via IMS core element. In this type of SMS over LTE, SMS is to be transmitted is encapsulated in a SIP message in IP-SM-GW entity. This type need LTE UE having both IMS and SIP protocol stack as well as IP Short message gateway(IP-SM-GW), IMS core as well as HLR/HSS(home subscriber server) which supports SMS over IP with the help of home routing.


Hope this helps. Tried to find the Call flow but could not locate :(

answer Aug 20, 2015 by Salil Agrawal
0 votes

enter image description here

enter image description here

answer Oct 6, 2015 by Saravanan Saran
Similar Questions
+4 votes

Since SG-SMS messages are carried over the downlink NAS is it possible that a flood of SMS messages from the SMSC can deny services to users in the affected cells? The use case is associated with location-based SMS.

If a large number of SMS messages are sent to a targeted group of users within a cell is it possible that the NAS cannot serve requests to establish connections from the UEs? Is it possible to prioritize the information carried over the NAS or, failing that, to randomize the selection of which messages are sent so that SMS does not prevent other service requests from being processed?

0 votes

In Other Words VoLTE Call Established and No Dedicated Bearers established by NW, Is it Possible the call will be stable ? Can It use IMS Defaulr Bearers for the Call?

Contact Us
+91 9880187415
#280, 3rd floor, 5th Main
6th Sector, HSR Layout
Karnataka INDIA.