Resource-constrained medium access control protocol for wearable devices

This work introduces a customized medium access control protocol, referred to as DrxMAC, for resource-constrained radio devices. The protocol is based on a time-slotted communication scheme with a simple automated slot allocation based on device identities. DrxMAC deploys an in-slot listen-before-talk approach to maximize the slot usage when multiple devices share a slot. The objective of our protocol is to minimize the use of the memory footprint and battery consumption. Further, it should be scalable even without support of a network infrastructure. DrxMAC is evaluated with a testbed implementation on Nordic Semiconductor's nRF24LE1 radio system on a chip. This system is often used for low-latency, low-throughput communication in consumer electronics such as wearables, wireless keyboards, or game controllers. It has recently been used in a large roll-out of wearable beacon devices that enable new personalized applications in entertainment theme parks. Such theme parks are controlled environments and can serve as model environment for smart cities. We believe that introducing adhoc networking for the wearable devices (as enabled by DrxMAC) will open the path towards new applications not only for theme parks but related applications in smart cities. We argue that our customized protocol approach improves the coverage range of such wearables and outperforms existing state-of-art protocols in terms of resource and energy efficiency. We compare different configurations and existing standard protocols proposed for sensor networks and the Internet-of-Things, and analyze the performance of our DrxMAC testbed implementation with focus on packet delivery ratio and energy consumption.