Project proposal Multi-stream and multi-path audio transmission - PowerPoint PPT Presentation

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Project proposal Multi-stream and multi-path audio transmission

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Project proposal Multi-stream and multi-path audio transmission Outline Multi-stream audio transmission Multi-stream vs. FEC Rate and error control Multi-stream using ... – PowerPoint PPT presentation

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Date added: 16 July 2020
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Title: Project proposal Multi-stream and multi-path audio transmission


1
Project proposalMulti-stream and multi-path
audio transmission
2
Outline
  • Multi-stream audio transmission
  • Multi-stream vs. FEC
  • Rate and error control
  • Multi-stream using path diversity
  • Multi-path to improve QoS
  • Proposed work

3
Multi-stream audio transmission
  • The incentives
  • Best-effort services vs. strict QoS requirements
    of real-time speech communication, e.g. latency,
    loss, rate variation etc.
  • Low bandwidth of the voice stream
  • The scheme

s1
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5
s2
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5 6
of consecutive lost packet 1 2 3 n
Loss length after recovery (packet) 0 .5 1 n/2-.5
4
QoS improvement with multi-stream (1) loss
recovery
  • Loss recovery
  • With m streams, when having n consecutive lost
    packet, the loss after recovery is
    max(n/m1/m-1,0)
  • Stronger protection at the cost of higher data
    rate
  • Lower loss rate indicates delay reduction

loss
delay
5
QoS improvement with multi-stream (2) delay
reduction
  • Reduction of delay and playout rate variation

6
Multi-stream vs. FEC (1)
s1
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3
4
5
Multi-stream
s2
1 2
2 3
3 4
4 5
5 6
Delay0
FEC protected single-stream Bolot, 96
2
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4
1
1
2
3
Packet Loss
2
4
1
1
3
3
Reconstructed
2
3
4
1
Two copies of payload data Delay1 packet
of consecutive lost packet 1 2 3 n
Loss length after recovery (packet) 0 1 2 n-1
7
Multi-stream vs. FEC (2)
  • Both add redundancy for data protection
  • Pros of multi-stream
  • Introduces lower delay for loss recovery
  • Provides stronger protection
  • Cons of multi-stream
  • Overhead from packet header is higher
  • Smaller transmission interval

8
Joint rate and error-protection control for
multi-stream
  • What if network congestion?
  • Decreasing audio stream rate does not necessarily
    alleviate the problem
  • Add stronger protection against loss and delay
    variation without increasing the total rate
  • Solution use more streams with different speech
    codec
  • One more issue header compression

9
Multi-stream with path diversity
  • Packets from source to destination sent
    explicitly over different links to use path
    diversity
  • Previous work on path diversity
  • Internet path selection Savage, 99
  • One paper on reliable video comm. using MSE
    Apostolopoulos, VCIP 01
  • Network behavior averaged
  • Burst loss converted to isolated loss
  • Outage probability decreased

10
Multi-stream audio transmission using path
diversity
  • Path diversity for real-time speech
    communication reduced variation of network delay
    by selecting path
  • Can reduce playout delay and speech rate variation

R
1
Relay
Relay
2
Internet traffic
Internet traffic
S
The bottleneck
11
Path diversity to improve QoS
  • Loss recovery stronger protection than single
    path multi-stream
  • Reduction of delay and playout rate variation

12
Delay reduction (2)
  • Adaptive playout scheduling and speech scaling
    makes seamless switching between streams possible

13
Proposed work (1)
  • For single path multi-stream
  • Compare the performance of multi-stream and
    single-stream FEC at the same rate. Find the the
    packet loss/delay jitter behavior by ns
    simulation.
  • - Has to use ns simulator must compare the
    two schemes under the same traffic statistics.
    Experiments must be repeatable.
  • Study on the optimal rate and error control.

14
Proposed work (2)
  • For multi-path transmission
  • ns simulation based on reasonable network
    topology and traffic model.
  • - Network measurement in the real world is
    difficult. Relay server network, opt. path
    selection not available at present.
  • Design of the adaptive playout scheduling
    algorithm suitable for multi-stream.
  • Study the QoS improvement by using path diversity.
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