A Trace-Based Approach for Modelling Wireless Channel
Nguyen, G.T., Katz, R.H., Noble, B., Satyanarayanan, M.
The loss behavior of wireless networks has become the focus of many recent
research efforts. Although it is generally agreed that wireless communications
experience higher error rates than wireline, the nature of these lossy
links is not fully understood. This paper describes an effort to characterize
the loss behavior of the AT&T WaveLAN, a popular in-building wireless
interface. Using a trace-based approach, packet loss information is recorded,
analyzed, and validated. Our results indicate that Wave LAN experiences
an average packet error rate of 2 to 3 percent. Further analysis reveals
that these errors are not independent, making it hard to model them with
a simple two-state Markov chain. We derive another model based on the distributions
of the error and error-free length of the packet streams. For validation,
we modulate both the error models and the traces in a simulator. Simulations
based on traces yield an average TCP throughput of about 5 percent less
than simulations based our best error model.