Listen channel randomization for faster Wi-Fi direct device discovery

Wi-Fi Direct, now part of Android smartphones, makes it possible for Wi-Fi devices to communicate directly without passing through an access point. Before starting actual data exchange, two devices should apparently find each other through a device discovery process, called find phase. After identifying the limitation of the legacy find phase, incurring long discovery delay, we propose a simple and efficient scheme, called Listen Channel Randomization (LCR), in order to expedite device discovery. Both the legacy find phase and LCR are evaluated with our elaborate Markov model and ns-3 simulations for comprehensive comparisons. Moreover, we have implemented a prototype of LCR in Android smartphone. Our experimental results reveal that LCR can significantly reduce the device discovery delay, yielding up to 72% delay reduction compared to the legacy find phase.