Wake-Up-Receiver Concepts - Capabilities and Limitations

A promising idea for optimising the power consumption of mobile communication devices represents the usage of an additional ultra-low-power receiver unit, which is able to control the main transceiver in order to reduce the standby power consumption of the overall system. Such a Wake-Up-Receiver (WuRx) unit senses the medium and switches on the communication interfaces in case of an external request. Otherwise, all system components for the network communication are completely switched off. Especially in the domain of resource-limited and embedded devices, WuRx technologies enable novel communication paradigms. But on the application layer, not all scenarios allow the efficient usage of such WuRx technologies. Dependent on environmental parameters, technological limitations and conceptual requirements, different strategies are necessary to ensure energy-efficient system operation. In this article, we present a critical analysis of the capabilities and the conceptual limitations of WuRx approaches. Therefore, we identify critical parameters for WuRx concepts, which limit the efficiency in real world scenarios. Our goal is to classify sufficient fields of application. Furthermore we evaluate the influences of these parameters on the system behaviour. In addition, we introduce heterogeneous energy harvesting approaches as an efficient way for the system optimisation. The proposed technologies are capable to be integrated into small-sized wireless sensor platforms and prolong the system uptime significantly. The presented simulation results are focusing on actual smart metering scenarios and wireless sensor networks. Based on these measurements, we were able to apply further optimisation steps within the system configuration on the application layer. In this context, we focus on application-specific key issues, like the trade-off between measurement quality and quantity, the usage of data buffering approaches and QoS capabilities.