Testbed to Study the Capture Effect: Can We Rely on this Effect in Modern Wi-Fi Networks

Abstract

In dense networks, interference is the main problem which causes throughput degradation. While it is often considered that fully or partially overlapping frame transmissions lead to collision and loss of both frames, in reality, sometimes at least one frame can survive if its receive power is higher than that of another frame by some predefined value. The ability of a device to receive the stronger frame if it comes later than the weaker one is called capture effect. For various devices, the capture effect is manifested in different ways. Specifically, we can distinguish preamble and frame body capture effects. The core contribution of the paper is an original testbed which can be used to study the capture effect for numerous off-the-shelf devices in massive experiments. With this testbed, we show that the majority of existing devices follow the standard and do not capture stronger frames during reception of the body of a weaker frame, which limits the performance of Wi-Fi networks in scenarios with hidden stations.