12/10/2006ConfidentialSlide 1 Video Streaming over UMTS: practical issues Stefan Rugel, Klaus Schäfer February 2008

12/10/2006ConfidentialSlide 2 Agenda 1.Scenarios for video streaming in mobile networks 2.Influences on Video Streaming Quality Problems Summary

12/10/2006ConfidentialSlide 3 Scenarios for (Video) Streaming in Mobile Networks Internet Mobile Network Mobile Operator & Partner mobile content, e.g videos: pay per video mobile content: pay per byte Increasing Bandwidth Increasing Streaming Capability More streaming content Mobile Internet

12/10/2006ConfidentialSlide 4 Scenarios for (Video) Streaming in Mobile Networks Dedicated mobile content provided by network operators, partners and independent mobile web sites. Content adapted to SW-platform, display and bandwidth. Growing streaming capability of handsets (display, UMTS, software) Mobile Internet: Limitations due to bandwidth and software interoperability. Mobile Devices: Notebooks with wireless access: Fixed-internet user experience limited by bandwidth.

12/10/2006ConfidentialSlide 5 Scenarios: Some types of Video Streaming File Format Player Availability on Mobile Devices Streaming Features Session Control / Transport.flv Adobe Flash Player Restricted Progressive Download, Restricted Media Control HTTP / TCP.wmv Windows Media Player Restricted Constant Bitrate, Bandwidth Adaption Media Control RTSP / TCP.3gpReal PlayerAvailable Contstant Bitrate, Media Control RTSP / RTP(UDP).rmReal PlayerAvailable Constant Bitrate, Bandwidth Adaption, Media Control RTSP / RTP (UDP) Without bandwidth constraints, progressive download is the best choice (simple, cheap) => todays internet dominated by Flash.

12/10/2006ConfidentialSlide 6 Scenarios: Video Streaming Bandwidth 0.1 Mbit/s kbit/s UMTS Bearer Mobile Content Open Internet HSDPA Quality Improvement? UMTS bearer (384 kbit/s) too low for open internet streaming. No changes by codec improvement

12/10/2006ConfidentialSlide 7 Influences on Video Streaming Quality wireless If: Quality limit regarding Bitrate, jitter / packet loss Proxies: Adapts content presentation to capabilities of mobile device, may improve protocol dynamics with regard to wireless access conditions. Firewall:May block RTP streams. Mobile Device: Quality of implementation is crucial for video quality. May compensate shortcomings of wireless access. Server:Special care with encoding and compression in order to meet conditions at wireless interface. Streaming Quality depends on many factors

12/10/2006ConfidentialSlide 8 Measuring of User perceived quality Network Traces, DPI Customer Experience only spot checks expensive Test Equipment Network wide Overview on Quality, network centric Quality view. Use Case Statistics

12/10/2006ConfidentialSlide 9 Measuring of User perceived quality (Core Network) Quality Statistics: RTCP Receiver Report (Packet Loss, Jitter). TCP Analysis Bandwidth measurement Open Internet: Statistic on Protocols used RTSP (Flash): User Behaviour statistics Open Internet: how many sessions do not get enough bandwidth?

12/10/2006ConfidentialSlide 10 Measuring of User perceived quality TCP graph core network of open internet streaming (windows media player) with UMTS bearer. Stream bitrate > throughput capacity  low (no) quality Automatisation & Statistics ! Slope: 384kbit/s transmitted bytes to mobile Acked bytes by mobile Receiver Window

12/10/2006ConfidentialSlide 11 Quality Model High minimum key frame rate: lower video quality at given bitrate Low minimum key frame rate: RLC packet loss impacts video quality Influence RLC mode, TCP / UDP transport? Optimum key frame rate parameter (MTU size) often determined experimentally.

12/10/2006ConfidentialSlide 12 Capacity and Video Streaming Quality Currently no issue: enough reserve. Dimensioning rules? Benefit of QoS?

12/10/2006ConfidentialSlide 13 QoS and Protocols: How long do we need RTSP/RTP Benefit of UDP, Effect of TCP Streaming Quality at capacity limit with TCP/UDP traffic mix

12/10/2006ConfidentialSlide 14 Video Streaming in Mobile Networks: Main Issues Good Video Streaming Performance in UMTS networks with dedicated mobile content. Open internet streaming only partly successful, improvements with HSDPA expected (will mobile networks keep up with fixed internet access then?) Quality of Service needed in higher loaded networks? Will RTSP/RTP survive? Definitions/Algorythms for network KPIs for end user streaming quality?

12/10/2006ConfidentialSlide 15 Thank you.