CrossTrace: Cross-Layer Measurement for IEEE 802.11 Wireless Testbeds

In this paper, we introduce and evaluate Cross Trace, a framework for performing cross-layer measurements in IEEE 802.11 based wireless networks. Cross Trace allows tracing of parameters at MAC-, routing and transport layer in a controlled environment and in a repeatable manner. Possible areas of application include network performance analysis and protocol optimization. Using Cross Trace, we conduct a comprehensive measurement study in a miniaturized testbed, in which we analyze the behavior of the IEEE 802.11 MAC-layer with respect to signal strength and bit error rate. We derive the delivery probability and bit error rate dependent on signal strength and MAC-layer data rate with and without interfering background traffic. We show that even moderate background traffic can significantly degrade network performance.