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Channel Measurement and Modelling

Channel measurement and modeling are both important scientific disciplines for wireless systems in order to well optimize the design parameters of transmitters and receivers. DSV’s expertise in channel measurement and modeling mainly covers UWB wireless systems for communication and localization. While narrowband channels are often modeled as frequency flat, wideband and UWB channels are typically frequency selective; moreover, opposite to wide band antennas, UWB antennas need also to be modeled as frequency selective since the bandwidth is of similar range as the carrier frequency causing the antenna radiation pattern to vary significantly over frequency. Especially this latter property makes UWB measurement and modeling a rather unique and time-consuming challenge; for instance, beside the classical channel parameters like carrier frequency, bandwidth and delay spread, antennas are characterized by several parameters and functions, like the antenna radiation pattern, the directional gain, the polarization, the matching circuit – all of them are now varying with frequency meaning that a full new dimension to the measurement and modeling of UWB channels has to be investigated. Last but not least, DSV additionally focuses on multiple antennas, meaning that also frequency selective coupling between the antenna elements has to be considered for UWB-MIMO wireless systems.

For those reasons, DSV scientists developed a new UWB-MIMO measurement and modeling methodology: starting with an UWB-MIMO measurement system consisting of 4 independent transmit and 4 receive chains and a maximum transmit bandwidth of 5.8 GHz, a comprehensive mathematical framework for the deterministic description of the UWB-MIMO channel including all relevant antenna parameters and functions has been derived. Moreover, a commercial ray tracing software has been adapted to our modelling needs for communication related scientific challenges. Opposite to that, an UWB-MIMO ray tracer has been self-developed for localization related scientific challenges, since the exact modeling of the direct path between transmitter and receiver is of utmost relevance for the reliable performance evaluation of localization methods.

In the future, DSV will focus on extending its UWB-MIMO expertise to EB-MIMO systems.