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Coded Wireless Video Broadcast / Multicast: A Cross-layer Framework With Protections To Harvest The True Potential of 4G Access Networks

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Title: Coded Wireless Video Broadcast / Multicast: A Cross-layer Framework With Protections To Harvest The True Potential of 4G Access Networks


1
Coded Wireless Video Broadcast / Multicast A
Cross-layer Framework With Protections
To Harvest The True Potential of 4G Access
Networks
James She, Ph.D. Research Fellow, Computer
Laboratory Presentation _at_ The Chinese
University of Hong Kong, Hong Kong Jan 2011
1
2
Outline
  • Introduction Background
  • A Preliminary Cross-layer Design
  • Coded Wireless Video Broadcast/Multicast
  • An Information-theoretical Bound of Expected
    Distortion
  • Conclusion Future Work

2
3
4G/Broadband Wireless Access and 1-to-many/all
Video Applications
4
Wireless Broadcast/Multicast and Problems
In a single-hop wireless network
  • efficient use of spectrum
  • higher system scalability
  • 2. Error Control
  • Retransmission
  • ? Not efficient or scalable

4
5
Research Objectives
  • Limitations of Existing Cross Layer Designs
    (CLDs)
  • Many for unicast are not applicable
  • Some for multicast/broadcast using
    erasure/network codings
  • Some statistical number of receivers within a
    multi/broadcast group
  • Multi-hop wired/wireless infrastructure
  • Research Objectives
  • Practical and generic cross-layer frameworks
    (advanced source channel coding) for single-hop
    network
  • Fundamental understanding of the proposed
    frameworks, using information theory
  • Possible implementations

5
6
Outline
  • Introduction Background
  • A Preliminary Cross-layer Design
  • Coded Wireless Video Broadcast/Multicast
  • An Information-theoretical Bound of Expected
    Distortion
  • Conclusion Future Work

6
7
A preliminary cross-layer design -
Superposition Coded Multicast
  • Layered Channel (Superposition coding)
  • Multi-resolution modulated (layered)
  • broadcast signals
  • Scalable Video Source (MPEG4/ H.264AVC)
  • Bitstream with successive refinable layers

8
Superposition Coded Multicast (SCM)
Base station
2 quality layers (base enhancement)
Receiver(s)
Novelty exploits the layered properties in
scalable source and multi-resolution channel
?BS only broadcasts/multicasts a single type of
radio signals that contains all
layers ?decodable by receivers at various
channel levels for multiple rate of video
delivery.
9
Simulation Results
  • Compare achievable video qualities (PSNR)
  • Normal Multicast vs. SCM
  • PS Normal uses the rate everyone supports

poor receiver (low SNR avg.)
good receiver (high SNR avg.)
Conclusion Higher video quality regardless of
the avg. channel SNR of a receiver!
9
10
SCM Summary
  • Two critical components identified
  • Scalable video (source)
  • Multi-resolution modulation (channel)
  • Resolved multi-user channel diversity video
    quality improvement.

10
11
Outline
  • Introduction Background
  • A Preliminary Cross-layer Design
  • Coded Wireless Video Broadcast/Multicast
  • An Information-theoretical Bound of Distortion
    Bound
  • Conclusion Future Works

11
12
Proposed - Coded Wireless Video
Broadcast/Multicast
  • Deal with error control multi-user channel
    diversity
  • Introduced protections to each successive layer
    at the source
  • Achievable by modifying the Multiple Description
    Coding based on Reed Solomon RS(N, K) 18

Note For any layer l, a smaller Kl value, the
higher robustness to tolerate fading duration for
that layer.
  • Each MDC/protected packet (with multiple layers
    of bitstreams) is sent through SCM as a
    multi-resolution modulated signal

18 P. A. Chou, H. J. Wang, and V. N.
Padmanabhan, Layered multiple description
coding, Proc. PV 13th Int. Packet Video
Workshop, Nantes, France, Apr. 2003.
12
13
System Model And Error Control Advantages
13
14
A Quick Video (000051-000205)
15
Formulations For Analysis
Performance/video quality measurement Total
received/recovered bitstreams, Tm, of a GoF by a
receiver m.
  • Prob. of receiving/recovering a layer l by
    receiver m
  • (i.e., receiving at least Kl partial packets of
    layer l by
  • receiver m)
  • With the layers dependency, the amount of
    received/
  • recovered bitstreams of a layer l in a GoF

layer l
Total received/recovered bitstream of a GoF
15
16
Optimized Experimental Results
  • Compare layered broadcast w/o protection (e.g.,
    SCM) and the proposed one
  • 2 layers w/ optimized (searched) parameters
  • 2 different standard video sequences (Foreman
    and Paris)

Note SS-1 lowest SNR avg. SS-10 highest SNR
avg.
(Foreman)
  • Coded Wireless Video Broadcast/Multicast
  • better video quality even in a poorer channel
  • smaller quality difference between receivers
    with highest and lowest SNR avg.

16
17
poor receiver
good receiver
Layered sourcechannel (SCM)
Layered sourcechannel with protection
18
Summary
  • Novelties
  • Introduced protections on successive layers over
    layered broadcast
  • Utilized partial MDC (protected) packets (never
    discussed in wired infrastructure)
  • Modified existing MDC for practical
    implementation
  • An analytical model for analysis and
    optimization.
  • ? Resolved both multi-user channel diversity and
    error control problems which are not possible in
    all previous and recent works 1-4
  • 1 Chris T. K. Ng et al., Recursive Power
    Allocation in Gaussian Layered Broadcast Coding
    with Successive Refinement, IEEE Intl. Conf. on
    Comm. (ICC), Jun 2427, 2007, Glasgow, Scotland,
    pp. 889896.
  • 2 C. Tian et al., Successive Refinement Via
    Broadcast Optimizing Expected Distortion of a
    Gaussian Source Over a Gaussian Fading Channel,
    IEEE Trans. on Information Theory, vol. 54, no 7,
    pp.2903-2918, Jul. 2008.
  • 3 Y. S. Chan et al., An End-to-End Embedded
    Approach for Multicast/Broadcast of Scalable
    Video over Multiuser CDMA Wireless Networks,
    IEEE Trans. on Multimedia, vol. 9, no. 3, pp.
    655-667, Apr. 2007.
  • 4 Murali R. Chari et al., FLO Physical Layer
    An Overview, IEEE Trans. on Broadcasting, vol.
    53, no. 3, pp. 145-160, Mar. 2007

18
19
Outline
  • Introduction Background
  • A Preliminary Cross-layer Design
  • Coded Wireless Video Broadcast/Multicast
  • An Information-theoretical Bound of Expected
    Distortion
  • Conclusion Future Works

19
20
Informaton-theoretical Bound of Expected
Distortion
  • Did you realize that we send less video data?
    Costs of protections
  • If / when the proposed framework is better than a
    similar layered broadcast WITHOUT protections?
  • The expected distortion without layers 3
  • where each source symbol is sent by a
    channel symbol under symbol error, perr.


3 X. Yu and En-hui Yang, Optimal quantization
for noisy channels with random index assignment",
Proc. of the 2008 IEEE Intern. Symp. Inform.
Theory, Toronto, Canada, July 6-11, 2008.
20
21
Bound of Expected Distortion

protected layered source symbols, Vi
x(i)
  • Each Vi ? a layered channel symbol, x(i), for
    each coded broad/multicast transmission
  • A receiver collects n channel symbols, x(1), ...
    ..., x(n) over n channel symbol durations.
  • Each x(i) is decoded into up to layer l
    with prob. upon the receivers
    instantaneous
  • channel condition.

21
22
Bound of Expected Distortion
After n channel symbol durations (or n
transmissions),
kL kl k1
  • The Bound of Expected Distortion
  • Applicable to a system without protection (i.e.,
    kl n)
  • The discreteness (i.e., binomial CDF terms) can
    be approximated by a normal CDF to determine
    optimal k values for optimization.

22
23
Numerical Anylysis -1
Fixed symbol error at layer 2
(a) higher pM,1 (k15, k22) (b)
lower pM,1 (k114, k22)
Fixed symbol error at layer 1
  1. higher pM,2 (k118, k21) (b) lower
    pM,2 (k118, k23)

23
24
Numerical Anlysis - 2
Expected distortions of two systems (with and
without protections) under various pM,1 in layer
1 and pM,2 in layer 2.
25
Simulation Comparisons
Layered broadcast without and with protections
under optimized parameters
Fixed lower, pM,2, in layer 2
Fixed higher, pM,2, in layer 2
Systems with their optimized configurations .
25
26
Summary of Expected Distortion
  • Novelties
  • A general closed-form formula for the bound of
    expected distortion
  • Generic to any (n, k) protection code and any
    number of layers (source/channel), useful for a
    new coding design
  • More accurate analysis/optimization, instead of
    using simply using throughput/bitstream amount.

27
Outline
  • Introduction Background
  • A Preliminary Cross-layer Design
  • Coded Wireless Video Broadcast/Multicast
  • An Information-theoretical Bound of Expected
    Distortion
  • Conclusion Future Works

27
28
Contributions
  • 1st framework using protections for tackling
    multi-user diversity and error control.
  • 1st realization through existing codings, as well
    as the associated analytical and optimization
    models.
  • 1st information-theoretical distortion bound for
    comparisons, and optimization through a simple
    search.
  • Advanced the fields by introducing a new design
    dimension protections, for cross-layer designs
    that was unapparent in the past literature.
  • LESS is MORE sometimes!

28
29
Future Work
  • Extend into cooperative communications under
    multi-BSs wireless networks (e.g.,
    optical-wireless hybrid network) by considering
    space-time coding
  • Promising results from preliminary investigations
    in EPON-WiMAX access networks

Final Remark a cross-layer design with
protections is shown to be useful in cooperative
networks for better video broadcast/multicast
29
30
On-gogin Research and Industrial Collaborations
  • WiMAX/LTE BS system and
  • cooperative broadcasting networks
  • (prototype and research)
  • SPC chipset and software-defined radio platform
    (research)

Electrical Computer Engineering
(Taiwan)
(Italy)
  • New scalable source coding with protection
    (research)

(Saudi Arabia)
Electrical Computer Engineering
(Ottawa)
  • Coded MIMO Broadcast/Multicast
  • (research)
  • WiFi platform (prototype)

Electrical Electronic Engineering
31
Acknowledgement
Prof. Pin-Han Ho, University of Waterloo Prof.
En-hui Yang, University of Waterloo Dr. Xiang Yu,
Research-In-Motion

Sponsors
IPMG
Collaborators
31
32
Collaborations and students
  • Looking for like-minded researchers and
    organizations/industries for collaborations and
    funs!
  • Looking for smart, creative and entrepreneurial
    students to join me as my research interns.
  • Email james.she_at_cl.cam.ac.uk
  • Web http//www.cl.cam.ac.uk/js864

32
33
The End
THANK YOU
33
34
Selected Publication From This Research
SCM 1 J. She, et al., IPTV over WiMAX Key
Success Factors, Challenges and Solutions, IEEE
Communications Magazine, vol. 45, no. 8,
pp.87-93, Aug. 2007. (Top 50 most accessed
article in IEEE Xplore 2008, and cited in
Wikipedia under MobileTV) Coded Wireless Video
Broadcast/Multicast 2 J. She, et al., A
Cross-Layer Design Framework for Robust IPTV
Services over IEEE 802.16 Networks, IEEE Journal
of Selected Areas on Communications (JSAC), vol.
27, no. 2, Feb. 2009, pp. 235-245. 3 J. She, et
al., A Framework of Cross-Layer Superposition
Coded Multicast for Robust IPTV Services over
WiMAX, Proceedings of the IEEE Wireless
Communication and Networking Conference, pp.
3139-3144, Mar. 2008, Las Vegas, Nevada, USA.
(Nominated for the Best Student Paper
Award) Expected Distortion Comparison 4 J.
She, et al., Distortion Comparisons For
Protected Successive Refined Over Broadcast
Channel , submitted to Trans. Multimedia, Jul.
2010. L-SPC 5 J. She, et al., Logical
Superposition Coded Modulation, submitted to
Trans. Wireless Communication, Nov. 2010.
34
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