This paper analyzes different packetization strategies that significantly improve the quality of H.263 coded video transmission
in wireless local area networks (WLANs). We show that a considerable improvement can be obtained with the proper combination
of error concealment techniques and transmission unit (TU) sizes. Moreover, we present performance evaluation results on critical
system parameters for interactive video over Ad—Hoc WLANs, and propose a simple rule to specify TU sizes. We use
Kinesis, a novel system architecture for packet video, as a software measurement tool to analyze the effects of packetization policies,
distance, network offered load, and interference from co—located WLAN devices on overall video quality.
Kinesis supports IP multicast extensions, overcoming delay issues introduced by the complex retransmission schemes in the IEEE 802.11
MAC sublayer, which are not acceptable for real—time services. It implements real—time transport protocol functions to manage
synchronization and QoS, and performs software—only real—time H.263 video encoding.
In this paper we address most common Ad—Hoc WLAN configurations, and present experimental results on Packet Error Rates, Frame
Error Rates, frame delays and latency, and Peak Signal-to-Noise Ratio for well—known test video sequences.
This work has been supported in part by SeCyT, Universidad Nacional de Córdoba, and by a grant from the Agencia Córdoba Ciencia.