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Wireless IPTV issues and solutions

Wireless IPTV issues and solutions. Chen Zhifeng Electrical and Computer Engineering University of Florida. Outline. What is IPTV? IPTV application and protocols Wireless video technical considerations Coding issues for wireless video and solutions networking issues and solutions

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Wireless IPTV issues and solutions

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  1. Wireless IPTV issues and solutions Chen Zhifeng Electrical and Computer Engineering University of Florida

  2. Outline • What is IPTV? • IPTV application and protocols • Wireless video technical considerations • Coding issues for wireless video and solutions • networking issues and solutions • 802.11g Connectivity issues and solutions • System considerations

  3. What is IPTV? • Traditional TV distribution technologies: terrestrial, satellite and cable. --However, cable can be upgraded to two-way capability and can thus also carry IPTV. • Two kinds of Internet Protocol Television: a) IPTV --supplied by a broadband operator using a closed network infrastructure -- need a massive connectivity infrastructure upgrade -- User experience is bound to their living rooms and set-top boxes. b) Internet Television --delivery of TV content over the public Internet --anyone can create an endpoint and publish that on a global basis. --the publisher has a direct communication channel to the consumer

  4. IPTV application and protocols • live TV --real time a) multicasting -- application layer : Client/Server mode -- network layer: Internet Group Management Protocol (IGMP) version 2 --need support from multicast router b) P2P --emulate an IP multicast tree at the application layer --no need support from multicast router • Video on Demand --time shifted --use Real Time Streaming Protocol (RTSP) as the application layer --use Real-time Transport Protocol (RTP) and Real-time Transport Control Protocol (RTCP) as the transport protocol --Applications using RTP are less sensitive to packet loss, but typically very sensitive to delays, so UDP is a better choice than TCP for such applications.

  5. Wireless video technical consideration • Coding • H.264 • Networking • Application layer: RTSP • Transportation layer : RTP/RTCP/UDP/NAT/STUN • IP layer: Mobile IP • Connectivity • MAC layer: 802.11g/802.11e/802.11i/802.11n • Physical layer • System consideration -- Platform and CPU capability --Operation system and compiler environment

  6. Coding issues for wireless video • Why H.264? Network Abstraction Layer --The network-friendly design goal of H.264/AVC is addressed via the Network Abstraction Layer that has been developed to transport the coded video data over any existing and future networks including wireless systems. • Coding issues: --compression efficiency --Error-resilient mechanism --Channel rate Fluctuate issue --End-to-End Delay Control --Complexity

  7. H.264 coding for wireless channel

  8. Compression efficiency • Due to limited resources bandwidth and transmission power, compression efficiency is the main target for wireless video and multimedia applications. • H.264 solutions --Enhanced Motion compensation --Intra Prediction --Deblocking Filter --Context-Adaptive Variable Length Coding (CAVLC) and Context-Adaptive Binary Arithmetic Coding (CABAC)

  9. Error-resilient mechanism • Channel rate Fluctuate issue H.264 solution: --well-known temporal scalability • End-to-End Delay Control H.264 solution: --slice-structured coding --Flexible MB Ordering (FMO) --Data partitioning

  10. Complexity • low complexity integer transform and quantization • Still complexity issue: more complexity than H.263 and MPEG-4 Solution: fast algorithms to reduce the complexity of Motion Estimation --hexagon-based search (HBS) --Enhanced predictive zonal search (EPZS) --hybrid unsymmetricalcross multihexagon-grid search (UMHexagonS) --variable blocksize best motion detection (VBBMD)

  11. Networking issues • P2P issue: --Network Address Translators (NAT) protocol block the data transmitted directly between two clients under different private networks in many P2P (Peer to Peer) applications. --RTP uses a dynamic port range makes it difficult for it to traverse firewalls • Roaming Issue: roaming from one area to another with different IP subnet

  12. Transportation layer solutions • Solution for Cone NAT --STUN protocol --used by google talk • Solution for symmetric NAT --Traversal Using Relay NAT (TURN) --adopted in big enterprise network *STUN: Simple Traversal of User Datagram Protocol (UDP) Through Network Address Translators (NATs)

  13. IP layer solution --Mobile IP • Mobile IP --A mobile node can have two addresses: a permanent home address and a care-of address --A home agent (HA) stores information about mobile nodes whose permanent address is in the home agent's network. --A foreign agent (FA) stores information about mobile nodes visiting its network. Foreign agents also advertise care-of addresses, which are used by Mobile IP. • How to work: --Receive: packets are intercepted by the home agent, which then tunnels the packets to the mobile node's care-of address with a new IP header. The packets are decapsulated at the end of the tunnel to remove the added IP header and delivered to the mobile node. --Send: mobile node simply sends packets directly to the other communicating node through the foreign agent.

  14. Wireless vedio categories • Video over WAN (wide area network) • GSM network/3G network • Video over MAN (Metropolitan Area Network ) • WiMAX network • Video over LAN (local area network ) • WiFi network (course project focus on 802.11g) • Video over PAN (Personal area network) • Bluetooth/UWB network

  15. IPTV over WLAN

  16. 802.11g Connectivity issues and solutions • Quality of Service (QoS) issue: Delay/delay jitter/Packet loss --solution: prioritized access and scheduled access for WiFi Multimedia (WMM), presented in 802.11e • Security issue: --Solution: Wi-Fi Protected Access (WPA/WPA2) addressed by 802.11i • Bandwidth issue: although 802.11a/g achieve the maximum datarate at 54Mbps, their throughput are around 22Mbps. What’s more, the performance will drop-off while multi-users access at the same time --solution: Multiple In Multiple Out (MIMO) presented in 802.11n • Other issues should be considered: --Interference from other radio: Microwave, cordless phone, bluetooth, etc --Roaming between two APs. …

  17. System considerations • Platform and CPU capability • Intel xscale platform: Xscale CPU, high performance • TI PMP platform: ARM9+DSP architecture • Samsung platform: ARM9, relatively lower performance • Operation system and compiler environment • Embedded Linux: open source but limited resources for wireless multimedia • WinCE: not open source but plentiful board support package for wireless multimedia application

  18. REFERENCES • [1] L. Yang, K. Yu, J. Li, and S. Li, “An Effective Variable Block-Size Early Termination Algorithm for H.264 Video Coding,” in IEEE RANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY, VOL. 15, NO. 6, JUNE 2005 • [2] T. STOCKHAMMER, and T. WIEGAND, “H.264/AVC for Wireless Applications” • [3]A. Leon-Garcia, and I. Widjaja, “Communication Networks Fundamental Concepts and Key Architectures,” 2nd edition • [4] http://en.wikipedia.org/wiki/IPTV • [5]http://www.masternewmedia.org/2005/06/04/iptv_vs_internet_television_key.htm

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