Smooth Handoff with Multipath Transmission

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Smooth Handoff with Multipath Transmission

• Yi Pan, Tatsuya Suda
• ypan, suda_at_ics.uci.edu
• Net-research Group_at_UCI

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Motivation

• Current handoff techniques
• Single mobile IP binding may cause packet loss
  during handoff
• handoff causes transmission rate reduction
• Because disparity of available bandwidth in
  different cells make the congestion window in the
  previous cell invalid

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Basic Ideas

• 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 loss due to hand off
• To increases throughput to a single 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 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

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 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

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

• 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

Data belong to Basic Layer
Data belong to Enhanced Layer
Path2 to COA2 and path1 to COA1 are both used to
multicast data packets to the mobile node
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Preliminary Simulation

• 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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Preliminary Simulation

• 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
• Forwarding local packet forwarding service is
  enabled by fast mobile IP handoff protocol among
  base stations
• Multi-path handoff scheme
• Handoff with multiple mobile IP bindings

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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. The base layer video throughput
is adjusted to the lower rate available
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 to achieve smoother video frame rate

(a) Mobile node enters a new cell with a larger
amount of bandwidth
(b) Mobile node enters a new cell with a smaller
amount of bandwidth
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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
• Provide smooth end-to-end stream media handoff
  with wide range of bandwidth changes from cell to
  cell
• Merits of the proposed multi-path handoff scheme
• Less packet loss during handoff
• duplicated packets are transmitted through
  multiple paths during handoff
• Quality improvement
• More important data (e.g., base layer video) is
  protected through transmission over multiple
  paths during handoff
• Minimum deployment required
• Only needs the sender and the mobile node to
  participate in the proposed scheme