Klaus Witrisal

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The need for low-complexity devices with low-power consumption motivates the application of suboptimal noncoherent ultra-wideband (UWB) receivers. This article provides an overview of the state of the art of recent research activities in this field. It introduces energy detection and autocorrelation receiver front ends with a focus on architectures that(More)
A discrete-time equivalent system model is derived for differential and transmitted reference (TR) ultra-wideband (UWB) impulse radio (IR) systems, operating under heavy intersymbol-interference (ISI) caused by multipath propagation. In the systems discussed, data is transmitted using differential modulation on a frame-level, i.e., among UWB pulses.(More)
The application of a fractionally sampled autocorrelation receiver (AcR) is proposed for the demodulation of transmitted-reference (TR) signals, to simplify synchronization and suppress nonlinear intra-symbol-interference and inter-symbol-interference (ISI) by means of linear weighting. A system model is presented for the TR system and its statistical(More)
In transmitted reference ultra-wideband (TR-UWB) systems and differential transmitted reference (DTR-UWB) systems, the performance is, besides to noise, determined by interference among pulses due to the dispersive multipath radio channel (interframe interference). The multiple access interference is also heavily influenced by multipath propagation. As a(More)
The autocorrelation receiver (AcR) is a suboptimum, low-complexity receiver architecture particularly suited to ultra-wideband (UWB) communication systems. As the bit rate increases, interference among pulses due to multipath propagation causes serious impairments of the AcR’s performance. To mitigate this effect, we propose an appropriate design of the(More)
Location awareness is one of the most important requirements for many future wireless applications. Multipathassisted indoor navigation and tracking (MINT) is a possible concept to enable robust and accurate localization of an agent in indoor environments. Using a-priori knowledge of a floor plan of the environment and the position of the physical anchors,(More)
Multipath propagation is one of the key problems for indoor localization systems. Strong multipath components can cause range estimates to anchor nodes to be severely biased. If a floor plan is available, reflected signal paths can be used effectively by mapping them to virtual anchors. We show how to make use of the rich localization information provided(More)
Ultra Wideband (UWB) impulse radio is an emerging technology, used in high speed, high precision, short range wireless communication systems. Transmitting ultra-short information bearing impulses in the order of nano-seconds, a huge bandwidth is used, which allows high data rate applications. This thesis focuses on transmitted reference (TR) UWB, and aims(More)