Integration of the ultra-low power WiseMAC with the μ111 Real Time Operating System: a performance evaluation

Many communication solutions for low power wireless sensor networks (WSN) rely on monolithic implementations instead of Operating System (OS) features, properties and services. Such OS-less approach implements the timings, state-machines and functions into a single software including scheduling and synchronization. This means that porting a protocol on a new hardware requires the rewriting of major software parts and at least the low-level drivers and implies full re-testing. Using a low-resource, low footprint Real Time Operating System (RTOS) would instead allow for an easy and efficient implementation of applications, whose complexity is reduced by using the OS features and services who acts as a convenient abstraction layer. The general feeling is that, however, the presence of the OS would impact the performance of the wireless communication, in particular with respect to latency and power consumption. This paper describes the results obtained by integrating the μ111 RTOS with the ultra-low power Medium Access Control (MAC) protocol for Wireless Sensor Networks WiseMAC [1], [2], showing that the impact of the OS in terms of energy consumption and hardware resources utilization is minimal if not null.