A measurement study of channel dynamics in wireless mesh networks

Wireless channels are inherently time-varying due to many different factors, such as fading, shadowing, multipath effects, etc. In practice, it is too complicated to completely capture these factors in a single theoretical framework. Therefore, many simplified channel models have been proposed and widely used in theoretical analysis, protocol design and performance evaluation. However, recent studies show that these well-accepted channel models are inaccurate in practical wireless environments. In this paper, we carry out a measurement study of the wireless channels with the objective of characterizing the channel dynamics. Based on the measurement results from an indoor wireless mesh network testbed, we investigate the short and long term variations, temporal and spatial correlations, transition probability, and the asymmetric link quality of the wireless channels in the indoor environment. Some key issues for applying the measurement-based models in protocol design, performance evaluation and simulation are discussed.