T-1 1 0 .4 5 6 Next generation cellular netw orks Multim edia - - PowerPoint PPT Presentation

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T-1 1 0 .4 5 6 Next generation cellular netw orks

Multim edia Services in Mobile and W ireless

Helsinki University of Technology Telecommunication Software and Multimedia Laboratory Konstantin Moroz

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Overall structure

Introduction & motivation RTP monitoring agents and Streaming Agents Handover packet loss problem Server Selection and Request Streaming Services in Integrated Cellular/ WLAN Environments

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Introduction

Wireless environment:

Limited bandwidth & high bit error rate Moving device -> handoffs -> packet loss

Main goal is to reduce errors in the wireless networks Streaming services in heterogeneous networks

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Introduction & motivation RTP monitoring agents and Streaming Agents Handover packet loss problem Server Selection and Request Streaming Services in Integrated Cellular/ WLAN Environments

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RTP monitoring

Monitoring Agent, a new type of proxy Helps to determine if the loss took place in the wired or wireless segment

[ 1]

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Streaming Agent

Upgraded version of RTP agent Sends statistical and timely feedbacks to the sender Timely feedbacks are ACK/ NAK packets Usefulness of information (statistical/ timely feedbacks) Analysis of SA timely feedbacks Shaping point

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Introduction & motivation RTP monitoring agents and Streaming Agents Handover packet loss problem Server Selection and Request Streaming Services in Integrated Cellular/ WLAN Environments

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SA

[ 2]

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Available solutions:

Mobile IP Hierarchial mobile IPv6 Fasthandover Main problem: these solutions require considerable changes to the IP networks

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End-to-end approaches

• no change to the IP networks
• suffer from considerable packet loss during handover
• Trade-offs

[ 3]

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Soft IP handover

Main goal: not to change the existing IP network

minimizes packet losses during handover minimizes wireless errors

Techiques:

Multihoming Bicasting FEC

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Multihoming

more than one IP network interface -> single connection with multiple IP addresses soft handover between two different IPs priority

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Bicasting

• encode the data stream,
• split it with more diversity than the general bicasting
• and send same data down the both paths.
• Possible scenarious:
• both links have weak signal
• ne of the links has a better signal

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FEC (Forward Error Correction)

• In case the packet is lost on both links

[ 3] FRAGMENTATION AND FORWARD ERROR CORRECTION

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FEC cont.

• extend msg from k to n symbols, adding (n-k) redundant
• symbols. Up to (n-k) corrupted symbols within the

extended msg can be recovered. Examples:

• MMSP(Mobile Multimedia Streaming Protocol) was

implemented and it's performance measured. FEC's impact on the quality of MPEG-4 streaming applications was evaluated.[ 3]

• SCTP(Stream Control Transmission Protocol) also

multihoming used.

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Problems and disadvantages of the new solution:

double connection computational delay no security

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Introduction & motivation RTP monitoring agents and Streaming Agents Handover packet loss problem Server Selection and Request Streaming Services in Integrated Cellular/ WLAN Environments

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Mobility-Aware Server Selection and Request Routing in Mobile CDN Environments.

Problem

• new path with different characteristics
• QoS degradation in streaming media

Proposed solutions

keep track of host different methods

• SMIL (Synchronized Multimedia Integrated Language)

update [ 4]

• extended RTSP (Real Time Streaming Protocol) methods

[ 5]

• advanced techniques [ 6]

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SMIL update

[ 4]

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SMIL update Cont.

[ 4]

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Introduction & motivation RTP monitoring agents and Streaming Agents Handover packet loss problem Server Selection and Request Streaming Services in Integrated Cellular/ WLAN Environments

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Integrated Cellular/ WLAN Environments

Main idea: integration of WLAN & 3G technologies Advantage: fast access in hot-spot areas Two basic methods for integration

Tight coupling Loose coupling

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Tight coupling

• WLAN connected to GPRS core network.
• WLAN may either emulate a radio network controller

(RNC) or a SGSN(Serving GPRS Support Node).

• WLAN is like any other GPRS routing area in the system

Interworking unit (IWU) is needed to interface WLAN to the GPRS core network. Main advantages:

• mechanisms for mobility,
• QoS and security in the core network can be reused.
• Handover only takes place when the mobile user either

enters or leaves a hotspot area.

• IP address doesn't change during the handover, since

the client stays in the same GGSN.

• when the hotspot areas and cellular areas overlap, it is

up to user to choose the handover or not

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Loose coupling

• WLAN interfaces directly with the IP-PDN and has no

direct interface with the GPRS core network.

• WLAN and cellular network are two separate access

networks.

• Protocols for authentication, accounting and mobility

must be deployed.

• WLAN is like a visiting network to the UMTS/ GPRS core

network during handover a mobile user is given a new IP address.

• Seamless handover requires advanced mechanisms.
• Streaming in mobile and wireless environments is an
• pen research problem.[ 7]

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Tight vs Loose coupling

[ 7]

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Relevant work:

802.11 integrated into mobile phone

Elcotel research. Integration into Raptor smart phone [ 8] . Lower cost & higher data rates Viewed as complementary technology Challenges:

Module size, weight Power consumption Security issues-> additional software

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References

[ 1] T. Yoshimura, T. Ohya, T. Kawahara and M. Etoh, Rate and Robustness control with RTP monitoring agent for mobile multimedia streaming, Proc. IEEE Int. Conf. Communications(ICC 2002), April 2002. [ 2] G. Cheung and T. Yoshimura, Streaming Agent: A network proxy for media streaming in 3G wireless networks, Proc. IEEE Packet Video Workshop, April 2002. [ 3] H. Matsuoka, T. Yoshimura, and T. Ohya, A robust method for soft IP handover, IEEE Internet

• Comput. 18-24, (March/ April 2003)

[ 4] T. Yoshimura, Y. Yonemoto, T. Ohya, M. Etoh, and S. Wee, Mobile streaming media CDN enabled by dynamic SMIL, Proc. WWW2002, May 7-11, 2002, Honolulu. [ 5] M. Tariq and A. Takeshita, Management of cacheable streaming multimedia content in networks with mobile hosts, Proc. IEEE GLOBECOM2002, Nov. 17-22, 2002, Taipei, Taiwan. [ 6] M. Tariq, R. Jain, and T. Kawahara, Mobility aware server selection for mobile streaming multimedia content distribution networks. Proc. 8th Int. Workshop on Web Content Caching and Distribution, Hawthorne, NY, Sept. 29-Oct. 1, 2003. [ 7] V. K. Varma et al., Mobility management in integrated UMTS/ WLAN networks, Proc. IEEE ICC’03, May 2003, Vol. 2, pp. 1048-1053 [ 8] Master’s Thesis, Eduard Kuusmik, Wireless LAN integration into a mobile phone, Department of Signals and Systems Chalmers University of Technology Göteborg, Sweden, Conducted at Elcoteq Design Center Oy Salo, Finland, September 2004

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THANK YOU!