Research
Robust Unicast and Multicast Video Communication over Wireless Ad Hoc
Networks
The objective of this project is to develop efficient techniques for reliable
video streaming over wireless ad-hoc networks. Wireless ad-hoc network is a
collection of wireless mobile nodes, which dynamically form a temporary network
without infrastructure. Possible applications of video streaming over ad-hoc
networks include: a quick set-up video conferencing in a place without wireless
infrastructure; transmitting video on the battlefield; search and rescue
operations after disaster. There are many challenges for supporting video
traffic over ad-hoc networks. Due to the mobility of wireless nodes, the
topology of ad-hoc network may change often. Thus the established connection
routes between sources and receivers are likely to be broken during the period
of the transmission, which may cause interruption, pause, or jerkiness in the
received video signal. Other factors that influence the quality include high
random packet loss caused by wireless channel errors and small capacity of
wireless network.
- Unicast case: We propose a cross-layer scheme to address the above
problems. In network layer, the routing protocol will establish multiple paths
between the source node and the destination for video applications to enhance
the robustness of the system, and increase the bandwidth for an end-to-end
connection. When one path is broken during the transmission, the routing
protocol can still use other paths to transmit video traffic, and use
alternative paths in the middle nodes to rescue the packets that are stuck in
the broken path. In application layer, the agents will monitor the state of
the paths and allocate video traffic adaptively.
- Muliticast case: Our proposed approach distributes multiple descriptions
coding video stream to different multicast trees to enhance the robustness of
video distribution. We propose a multicast routing protocol, which establishes
multiple disjoint multicast trees for video distribution. We will show the
feasibility of building multiple disjoint multicast trees in wireless ad hoc
networks. We will also analyze and study the influence of different video
coding schemes and different methods of distributing video stream among
disjoint multicast trees on quality of real-time multicast video streaming.
We will verify our results using both simulations and real experiments on an
experimental testbed.
Selected Publications:
- W. Wei, A. Zakhor, "Multiple Tree Video Multicast over Wireless
Ad Hoc Networks", to appear in IEEE Transactions on Circuits and Systems for Video Technology.
- W. Wei and A. Zakhor, "Path Selection For Multi-path Streaming in Wireless Ad Hoc Networks",
International Conference on Image Processing, Atlanta, Georgia, October 2006.
- A. Zakhor and W. Wei, "Multiple Tree Video Multicast Over Wireless Ad Hoc Networks",
International Conference on Image Processing, Atlanta, Georgia, October 2006.
- W. Wei and A. Zakhor, "Multipath
Unicast and Multicast Video Communication over Wireless Ad Hoc Networks"
in International Conference on Broadband Networks (Broadnets) 2004, San Jose,
CA, USA, Oct. 2004(invited), pp. 496 - 505.
- W. Wei and A. Zakhor, "Robust
Multipath Source Routing Protocol (RMPSR) for Video Communication over
Wireless Ad Hoc Networks" in International Conference on Multimedia and
Expo (ICME) 2004, Taipei, Taiwan, June 2004. (Simulation codes are here.)
- W. Wei and A. Zakhor, "Connectivity
for Multiple Multicast Trees in Ad Hoc Networks" in International Workshop
on Wireless Ad-hoc Networks (IWWAN), Oulu, Finland, June 2004.
- X. Zhang and W. Wei, "Blind
adaptive multiuser detection based on Kalman filtering", IEEE Transactions
on Signal Processing, Jan. 2002, Pages:87 - 95