Smooth Video Handoff over Wireless Networks

1
Smooth Video Handoff over Wireless Networks

• Yi Pan and Tatsuya Suda
• ypan,suda_at_ics.uci.eduSchool of Information and
  Computer Science
• University of California, Irvine

2
Outline

• Motivation
• Proposed scheme
• Simulation and demo
• Conclusion

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Motivation

• Current handoff techniques
• Single mobile IP binding may cause packet loss
  during handoff
• Switching data transmission path is dangerous for
  active sessions
• Handoff causes transmission rate reduction
• Due to disparity of available bandwidth in
  different cells, the transmission rate in the
  previous cell may not be proper to avoid
  congestion in the new cell
• Network mobility support can not handle this
  problem

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Motivation

• Multimedia applications need a smooth handoff
  provides
• Reduced packet loss
• Continuous streaming
• Congestion avoidance in new cell
• Smooth adaptation of video quality to various
  bandwidth

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Our Proposal

• Use multiple paths to reach a single mobile node
• Assign different mobile IP addresses (COAs) to
  different paths reaching a single mobile node
• Exploit different amounts of bandwidth on
  multiple paths to a single mobile node
• To reduce or prevent a packet loss due to hand
  off
• To increase throughput for the mobile node

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Basic Ideas

• Preventing a packet loss due to handoff
• Sending a packet on multiple paths during handoff
  reduces loss
• When a packet is lost on one path due to handoff,
  the packet is still available on the other paths

COA1 is registered to Home Agent and
Corresponding Node and Path1 is used to send
packets to COA1
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Basic Ideas

• Preventing a loss due to handoff
• Sending a packet on multiple paths during handoff
  reduces loss
• When a packet is lost on one path due to handoff,
  the packet is still available on the other path

Path2 to COA2 and path1 to COA1 are both used to
multicast data packets to the mobile node
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Basic Ideas

• Preventing a loss due to handoff
• Sending a packet on multiple paths during handoff
  reduces loss
• When a packet is lost on one path due to handoff,
  the packet is still available on the other paths

While the mobile node moves out of the
transmission range of base station1, it loses
COA1 but the data packets are continuously
available through path2 to COA2
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Basic Ideas

• Exploit different amounts of bandwidth
• Multi layer video transmission on multiple paths
  during handoff

Data belong to Basic Layer
Data belong to Enhanced Layer
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Background Techniques

• Networking layer technique
• Multi-homing
• Mobile IP
• Transport layer technique
• TCP Friendly Rate Control (TFRC)
• Application layer technique
• Source Adaptive Multi-layer encoder

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Background Techniques

• Network layer technique
• Multi-homing
• One host gets multiple IP addresses
• Schemes to support multi-homing
• DHCP protocol in IPv4
• IPv6 address auto-configuration and multi-homing

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Background Techniques

• DHCP protocol in IPv4
• DHCP servers in the network can provide dynamic
  COA addresses for the mobile node
• By sending requests and getting COAs for multiple
  interfaces, the mobile node can acquire multiple
  COAs

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Background Techniques

• DHCP protocol in IPv4
• DHCP servers in the network can provide dynamic
  COA addresses for the mobile node
• By sending requests and getting COAs for multiple
  interfaces, the mobile node can acquire multiple
  COAs

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Background Techniques

• IPv6 address auto-configuration and multi-homing
• By suffixing the network prefix from the routers
  with hosts MAC address, multiple IPv6 COA
  addresses can be achieved

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Background Techniques

• Mobile IP
• Basic Mobile IP

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Background Techniques

• Mobile IP
• Basic Mobile IP

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Background Techniques

• Mobile IP
• Basic Mobile IP

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Background Techniques

• Mobile IP
• Options used
• Simultaneous binding (to support multi-homing)

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Background Techniques

• Route optimization

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Background Techniques

• Route optimization

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Background Techniques

• Route optimization

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Background Techniques

• Transport layer technique
• TCP Friendly Rate Control (TFRC)
• We use TFRC end-to-end rate control algorithm
  instead of TCP
• To avoid the high fluctuation of transmission
  rate resulting from the saw tooth shaped TCP
  window dynamics

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Background Techniques

• TFRC calculates the transmission rate using an
  equation below
• Packet loss rate p is calculated through a short
  history of observed packet loss, through a
  weighted averaging method

Nominal bandwidth
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Background Techniques

• Features of TFRC during congestion avoidance
  phase
• Fairness to TCP
• It achieves a long run throughput equal to the
  nominal bandwidth that a TCP session will occupy
  under the same congestion status
• Stable transmission rate
• It maintains a sustainable rate against
  intermittent packet around the nominal bandwidth.
  
• Thus, the fluctuation of transmission rate due to
  the saw-tooth shaped TCP window dynamics is
  largely reduced
• Quick reaction to congestion
• It reacts to persistent packet losses by forcing
  a reduction of transmission rate over several
  round trip time

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Background Techniques

• Application layer technique
• Source adaptive multi-layer encoder for stream
  media
• Multi-layer stream media
• Multiple encoding layers are applied in the
  encoder
• Base layer packets contain most critical data for
  the decoder
• Enhanced layer packets provide additional
  information to increase the quality of stream
  media

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Background Techniques

• Multi-Layered Video

Multi-Layer Encoder
Base layer
Raw Video
Enhancement layer
Base Enhancement Layers
Base Layer
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Technical Background

• Source adaptation multi-layer encoder
• Source adaptive multi-layer encoder takes ri, bi,
  ei as input parameters to video layer i
• ri is the transmission rate for video layer i
• bi is the buffered bits of video layer i to be
  sent to the network
• ei is the encoding error rate

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System Architecture

• Multi-path transport protocol design

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Components in the Architecture

• Path Management Module
• Exist in transport layer at both ends
• Keep a record of all available paths
• Assign rate control module for each available
  path
• Rate Control Module
• A pair of rate control modules exist at both ends
  for each available path
• Perform end-to-end feedback-based rate control on
  each path

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Components in the Architecture

• Multi-path Distributor
• Exist at the sender side
• Calculate and report the number of video layers
  and target encoding rates for video layers to the
  application (video encoder)
• Assign appropriate paths to each video layer and
  send the video packets through multiple paths

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Components in the Architecture

• Multi-path Collector
• Exist at the receiver side
• Receive video packets from multiple paths and
  reorder the buffered video streams
• Deliver the video streams to application (video
  decoder)

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Simulation Settings

• Simulation Scenario

Different Average background traffic volume in
different base stations are explored in simulation
Corresponding Node (source of video traffic)
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Simulation Settings

• Compared handoff schemes
• Single path schemes with single mobile IP
  binding
• No forwarding no local packet forwarding for
  mobile nodes is performed among base stations
• Basic Mobile IP technique
• Forwarding packets are relayed from the old base
  station to the new base station when the mobile
  node enters the new cell
• Represent network layer mobility enhancement
  techniques that repair the packet loss on a
  broken path for an active session
• Multi-path handoff scheme
• Handoff with multiple mobile IP bindings
• TFRC rate control is employed in all schemes to
  achieve smooth rate for stream media application

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Simulation Results

• Results and observations
• Video throughput when the mobile node moves from
  high bandwidth cell to low bandwidth cell

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Simulation Results

• Improved throughput

Multi-path handoff scheme keeps the video
throughput high but adjust the base video layer
to the lower rate
With different available bandwidth in the new cell
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Simulation Results

• Reduced packet loss

Multi-path handoff scheme keeps the packet loss
ratio low. Base layer is protected with
near-to-zero loss ratio
With different available bandwidth in the new cell
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Simulation Results

• Improved goodput
• With protection of base layer, the goodput is
  improved in terms of smooth video frame rate

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Video Demo

• Demo scenario

Received Video
Raw video at the sender
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Video Demo
Multi-path Handoff
Single path w/ Forwarding
Single path w/o Forwarding
Received video stream
Raw video at the sender
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Conclusion

• Contributions
• Integrate multi-layer encoding, multi-homed
  mobile nodes through a multi-path transport
  protocol
• Provide smooth end-to-end stream media handoff
  with wide range of bandwidth changes

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Conclusion

• Merits of multi-path handoff
• Less packet loss during handoff
• duplicated packets are transmitted through
  multiple paths during handoff
• Quality improvement
• Because more important data (e.g., base layer
  video) is transmitted over multiple paths during
  handoff
• Minimum deployment in network
• Only the end systems are needed

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• http//netresearch.ics.uci.edu/ypan/MPATH_strm
• Thank you!!!

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Supplementary Slides
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Related Works

• Stream Control Transport Protocol (SCTP)
• A protocol to delivery multiple data streams to a
  multi-homed host
• Multiple paths are not used for transmission
  simultaneously
• R. Stewart, Q. Xie, K. Morneault, C. Sharp, et
  al, Stream Control Transmission Protocol,
  RFC2960, Oct. 2000
• Multi-path TCP and p-TCP
• Send data packets on multiple paths in one TCP
  connection
• Packet loss is recovered through retransmission
• Window-based congestion control
• One congestion window for multiple paths
  (Multi-path TCP)
• One congestion window for each path (p-TCP)
• Multi-path TCP D. S. Phatak, Tom Goff, A Novel
  Mechanism for Data Streaming Across Multiple IP
  Links for Improving Throughput and Reliability in
  Mobile Environments, in Proceeding of
  Infocom02, Vol 2, Jun. 2002
• p-TCP Hung-Yun Hsieh and Raghupathy Sivakumar,
  A Transport Layer Approach for Achieving
  Aggregate Bandwidths on Multi-homed Mobile
  Hosts, in Proceedings of Mobicom02

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Related Works

• Proxy-based Video Streaming
• Using proxies to relay the video stream
• Switching proxies when user moves
• T. Yoshimura, Y. Yonemoto, T. Ohya, M. Etoh, and
  S. Wee, Mobile Streaming Media CDN enabled by
  Dynamic SMIL, in International World Wide Web
  Conference, May 2002