Header menu link for other important links
X
Adaptive FEC-based packet loss resilience scheme for supporting voice communication over ad hoc wireless networks
Published in
2008
Volume: 7
   
Issue: 10
Pages: 1184 - 1199
Abstract
Providing real-time voice support over multihop ad hoc wireless networks (AWNs) is a challenging task. The standard retransmission-based strategies proposed in the literature are poorly matched to voice applications because of timeliness and large overheads involved in transmitting small-sized voice packets. To make a voice application feasible over AWNs, the perceived voice quality must be improved while not significantly increasing the packet overhead. We suggest packet-level media-dependent adaptive forward error correction (FEC) at the application layer in tandem with multipath transport for improving the voice quality. Since adaptive FEC masks packet losses in the network, at the medium access control (MAC) layer, we avoid retransmissions (hence, no acknowledgments) in order to reduce the control overhead and end-to-end delay. Further, we exploit the combined strengths of layered coding and multiple description (MD) coding for supporting error-resilient voice communication in AWNs. We propose an efficient packetlzation scheme in which the important substream of the voice stream is protected adaptively with FEC depending on the loss rate present In the network and is transmitted over two maximally node-disjoint paths. The less Important substream of the voice stream is encoded into two descriptions, which are then transmitted over two maximally node-disjoint paths. The performance of our scheme (packet-level media-dependent adaptive FEC scheme) is evaluated In terms of two parameters: residual packet loss rate (RPLR, packet loss rate after FEC recovery) and average burst length (ABL, average length of consecutive packet losses after FEC recovery) of voice data after FEC recovery. The sets of equations leading to the analytical formulation of both RPLR and ABL are first given for a renewal error process. The values of both these parameters depend on FEC-Offset (r, the distance between original voice frame and piggybacked redundant voice frame) and loss rate present in the network. Then, these parameters are computed for a Gilbert-Elliott (GE) two-state Markov error model and compared with experimental data. Our scheme adaptively selects the FEC-Offset (it chooses 7' that minimizes RPLR and ABL as much as possible) based on the loss rate feedback obtained from the destination. The proposed scheme achieves significant gains in terms of reduced frame loss rate (FLR), reduced control overhead, and minimum end-to-end delay and almost doubles the perceived voice quality compared to the existing approaches. © 2008 IEEE.
About the journal
JournalIEEE Transactions on Mobile Computing
ISSN15361233
Open AccessNo
Concepts (54)
  •  related image
    AD-HOC WIRELESS NETWORKS
  •  related image
    ADAPTIVE FEC
  •  related image
    ADAPTIVE FORWARD ERROR CORRECTION
  •  related image
    Analytical formulation
  •  related image
    Application layer
  •  related image
    BURST LENGTH
  •  related image
    CHALLENGING TASK
  •  related image
    CONTROL OVERHEAD
  •  related image
    End-to-end delay
  •  related image
    ERROR MODELING
  •  related image
    ERROR PROCESS
  •  related image
    ERROR-RESILIENT
  •  related image
    Experimental data
  •  related image
    FRAME LOSSES
  •  related image
    LAYERED CODING
  •  related image
    Loss rates
  •  related image
    MEDIUM ACCESS CONTROL LAYERS
  •  related image
    MULTIHOP AD HOC
  •  related image
    Multimedia
  •  related image
    MULTIPATH TRANSPORT
  •  related image
    MULTIPATH TRANSPORTS
  •  related image
    MULTIPLE DESCRIPTION CODING
  •  related image
    NODE-DISJOINT PATHS
  •  related image
    PACKET LOSS RATE
  •  related image
    PACKET LOSS RESILIENCE
  •  related image
    PACKET OVERHEAD
  •  related image
    PACKETIZATION SCHEME
  •  related image
    Real-time voice
  •  related image
    RETRANSMISSION
  •  related image
    Retransmissions
  •  related image
    SUB STREAMS
  •  related image
    Two-state
  •  related image
    Voice applications
  •  related image
    VOICE DATA
  •  related image
    VOICE FRAME
  •  related image
    VOICE PACKETS
  •  related image
    Voice quality
  •  related image
    VOICE STREAMS
  •  related image
    Ad hoc networks
  •  related image
    Adaptive control systems
  •  related image
    Computer system recovery
  •  related image
    Error correction
  •  related image
    Forward error correction
  •  related image
    Germanium
  •  related image
    Image coding
  •  related image
    Iterative decoding
  •  related image
    Medium access control
  •  related image
    Packet loss
  •  related image
    Packet networks
  •  related image
    Programming theory
  •  related image
    Standards
  •  related image
    Telecommunication networks
  •  related image
    Troposphere
  •  related image
    Access control