Real-time H.263+ video transmission on 802.11 wireless LANs

Wireless video services in packet-switched environments constitute a significant challenge. While radio channels present limited capacity high error rates and time-varying and asymmetric propagation properties, video applications are bandwidth-killing, error-sensitive and delay-intolerant. This situation forces wireless video systems to dynamically adapt to changes in the network resources. In the recent past there have been some papers investigating video transmission over wireless networks (H. Liu and M. El Zarki, 1997; N. Chan and P.T. Mathiopoulos, 2000), performance of the transfer protocols proposed in the IEEE 802.11 standard (H.S. Chhaya and S. Gupta, 1996; J. Weinmiller et al., 1997), and real time video communications in packet-switched infrastructure networks (P. Bahl, 1998). However, no previous experimental work on video conferencing systems for IEEE 802.11 Ad Hoc WLANs supporting IP multicast extensions has been reported so far. The paper describes Kinesis, an H.263+video transmission system for 802.11 network. Kinesis supports IP multicast extension and implements real time transport protocols to manage synchronization and QoS issues. We focus on the system architecture as a general communication framework for distributed and interactive audiovisual applications. Kinesis has been tested under different working conditions, performing H.263+ video sequences with excellent results.