Multiple Sender Distributed Video Streaming

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Multiple Sender Distributed Video Streaming
IEEE TRANSACTIONS ON MULTIMEDIA 2004

• Thinh Nguyen and Avideh Zakhor
• Presented by
• Huang Wendong

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Introduction

• Multiple sender distributed video streaming
• Multiple senders and single receiver
• Independent routes from senders to the receiver
• Achieve higher throughput, increase tolerance to
  packet loss and delay due to network congestion
• Three main components in the proposed work
• Rate allocation algorithm
• Packet partition algorithm
• Receiver-driven transport control

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System Overview
Packet Partition algorithm
Estimate available bandwidth
Control
ACK
Sender 1
Data
Estimate RTT
Receiver
Rate Allocation algorithm
Estimate RTT
Data
Sender 2
Estimate loss rate
Packet Partition algorithm
Control
ACK
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Receiver-driven Transport Control

• Receiver
• Calculate the optimal sending rate using RAA
  based on the RTTs and estimated loss rates
• Monitor variations of each sender and readjust
  rate distributions among senders accordingly
• Sender
• Estimate and send its round-trip time to the
  receiver
• Run distributed PPA upon receiving the control
  packets
• Control packet format
• Synchronization sequence number RTT sending
  rates

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Rate Allocation Algorithm

• Objective
• Minimize the irrecoverable loss under fixed FEC
• Be fair to existing TCP traffic
• Setup of RAA
• Packet loss model Two-state discrete Markov
  chain
• FEC scheme RS(n, k), n and k are fixed for the
  entire streaming process
• Bitstream model single description and single
  layer bitstream

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Rate Allocation Algorithm(2)

• Mathematical model
• Subject to
• P(m,i,N) denotes the probability that i packets
  are lost out of N packets sent by m
• is the interval between the successive
  transmitted FEC blocks in seconds

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Rate Allocation Algorithm(3)

• Implementation
• Search over all possible values of and
• For M senders, the exhaustive search has
  complexity
• of

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Packet Partition Algorithm

• Objectives
• Run in distributed fashion
• All packets are sent by one and only one sender
• To minimize the startup delay
• Mathematical model
• Where the playback time of k-th packet
  with respect to
• the estimated
  arrival time of the k-th packet sent by j
• To maximize the time difference between arrival
  and playback time of the k-th packet

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Packet Partition Algorithm(2)

• Distributed calculation
• Each sender effectively keeps track of all the
  values of
• for all senders
• No need to synchronize all the senders clocks to
  a global time

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Packet Partition Algorithm(3)

• The choice of the synchronization sequence number
  in the control packet
• The lag among the senders needs to be as little
  as possible
• The aggregate bit rate for all senders remains
  constant
• where is the estimated sequence
  number for the latest packet sender j has just
  sent, before receiving the control packet.

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Experiments Results

• Numerical Characteristics
• Two common scenarios X and Y are considered
• FEC configuration RS(30,27), RS(30,25),
  RS(30,23)
• irrecoverable loss probability change
  significantly among various schemes
• Optimal packet partition scheme
• As the average bad time of route B increases,
  more packets are sent by route A for all three
  levels of FEC protection
• At the same average bad time of route B, the
  number of packets sent on route A decreases with
  increased FEC level

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Experiments Results(2)

• Single sender vs. multiple senders
• Irrecoverable packet loss is significantly
  reduced in multiple sender scheme
• Optimal RAA is more effective with stronger
  FEC schemes
• Sensitivity Analysis of Optimal Sending Rate
• Sensitivity of loss probability to deviations
  form optimal sending rates
• In case of strong FEC protection,a slight
  variation in the sending rate around the optimal
  value results in a smaller change in
  irrecoverable probability

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Experiments Results(3)

• Internet Experimental Results Show
• Multiple sender scheme can effectively combat
  burst
• packet loss
• In most cases, PPA provides interleaved packets
  with
• small lags

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• Conclusions
• The proposed work can effectively reduce overall
  packet loss rate
• Further work
• Adopt adaptive FEC schemes
• Employ scalable bitstream to accommodate the
  additional data

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• Thank You !