A 433 MHz wake-up-receiver has been designed and fabricated in 250 nm BiCMOS technology. In a novel approach, an off-chip switched SAW resonator accumulates energy from the radio wave and subsequently emits it as a voltage pulse. This mechanism delivers passive amplification and filtering of the input signal without additional power consumption. The integrated analog frontend evaluates the height of the voltage pulse in the context of on-off keying. The analog frontend circuitry draws 46 µA - 70 µA (meas.) from a 2.5 V supply. With a bitrate of 10 kbps, the energy per bit efficiency amounts to 17.4 nJ/bit without duty cycling. The active chip area measures 370 µm × 210 µm, In this implementation, a passive pulse voltage amplification of up to 24 dB and an input sensitivity of -78 dBm were measured. A detailed analysis of the switched SAW network in a realistic application shows that a passive voltage amplification of 32 dB is attainable. The functionality of the analog frontend has been verified by measurements.

In this paper we present the architectural design of the tiny scale very long instruction word (VLIW) soft-core processor TinyVLIW8. The processor is designed to achieve a minimal instruction execution time and design size. Although, the instruction repertoire is not large, it is dequate for control tasks, which require decision making that could not easily be implemented in an application specific integrated circuit (ASIC) and in which an extensive mathematical processing is not required. Especially in the area of embedded control tasks with real-time requirements an architecture using single-cycle instructions is key. We will illustrate an application of our TinyVLIW8 by presenting an design of a secure wake-up receiver for low power wireless sensor nodes. To the best of our knowledge, the presented soft-core processor is the smallest VLIW design with an average instruction execution time of one clock cycle only. The core consumes less than 6% of the logic cells of the smallest Altera Cyclone IV FPGA and can be used in a system-on-chip design as well.

The wireless Bluetooth standard, generally used for short range point-to-point communication between mobile devices, can in principle connect any number of stations into a multi-hop network. For this purpose a "scatternet" must be built up, which is a collection of small overlapping "piconets". Bluetooth technology is basically well-suited to some types of wireless sensor networks, but such deployment has been been limited due to the difficulty in setting up and maintaining a scatternet. We demonstrate the SFX algorithm, an extension of the earlier SHAPER procedure. The SFX algorithm builds up a scatternet by a decentralized procedure with the properties of self-organization, self-optimization, and self-healing. The procedure has been verified by deployment in a photovoltaic power plant.

Wireless sensor and actor networks based on Bluetooth technology require an algorithm to build up and maintain a Bluetooth scatternet. Although much research has been done, actual deployment is rare because a self-organizing and self-healing procedure suitable for actual Bluetooth nodes has not yet been developed. We present the SFX algorithm to build a scatternet tree with the required properties. The method was verified by simulations for up to 400 nodes and by field tests.