Continuous Wireless Link Rates for Internet of Things

Internet of Things has stringent requirements on the wireless network throughput for timely transmission of the big data being produced. In order to maximize the throughput over dynamic fluctuations of wireless channel quality, current wireless systems adapt the link rate to the instantaneous channel condition, but fail to fully utilize the channel capacity due to the discrete choices of available link rates and the gap between these rates. Instead, in this paper we present vMod, a lightweight and practical solution towards maximum wireless network throughput by redesigning the wireless link rates from discrete to continuous. The key idea of vMod is to modulate a fractional number of data bits into each symbol by employing the Variable-Length Code (VLC), which is able to statistically yield any link rate. We implemented vMod on software-defined radio platforms. Experiment results demonstrate that under highly dynamic wireless network conditions, vMod greatly improves the WiFi throughput by 30% over a single narrowband link, but incurs only negligible overhead.