A study on adaptive real time video over LTE

Abstract: LTE, The next generation mobile network system by 3GPP, only allows IP-based
transport. Traditional telephony services such as voice and video real-time
communication will be provided through the use of IMS (IP Multimedia
Subsystem) Multimedia Telephony (MTSI) which imposes high demands on the
transport channel. In a packet switched network any intermediary node can act
like a congestion bottle neck leading to delay or packet loss. In this
scenario a fast end to end adaptation scheme at the media layer can play a
vital role to secure service performance by ensuring high quality throughout
the session, even in extreme conditions, and keeps the service alive
avoiding session termination.

This thesis report describes a study of perceived video quality improvement
using end to end congestion control depending on both “pre-warning” for
congestion and packet loss observed at receiver in IMS video telephony over
3GPP LTE system according to 3GPP TS 26.114 V7.0.0. In the process of
achieving the goal a new adaptation state machine was developed with
different strategies to address the early congestion notification and packet
losses. Simulations has been carried out with different adaptation schemes
to compare results and benefits of newly proposed scheme. This thesis shows
the effectiveness of early congestion notification for real-time video
transmission and reveals some important aspects of adaptation procedure
which need to be considered while designing adaptation for video traffic to
avoid the congestion in a LTE network. The results found in the study
suggest the inclusion of ECN for UDP traffic for future network like LTE.