NIST UWB-MIMO Channel Propagation Measurements in the 2-8 GHz Spectrum


SITE PURPOSE:                           (CONTENTS)
To provide a standardized platform to design and test wireless telecommunication systems using actual channel propagation measurements in the spatial and frequency domains. This site enables downloading 200 different channel measurements taken in the 2-8 GHz spectrum between a single-element transmitter (TX) and a uniform circular array (UCA) receiver (RX). The measurements were taken in four different buildings with diverse construction materials. The TX-RX distance spans from a few meters up to 45 meters in both line-of-sight and non line-of-sight conditions. The measurements can be used amongst other applications to:
  • test the robustness of coding schemes to the channel;
  • design Multiple-Input Multiple-Output (MIMO) systems based on spatial diversity;
  • devise algorithms to extract time-of-flight and/or angle-of-flight in location-system design;
  • model the spatial-temporal channel.

    Any transmitter signal has a temporal-domain representation x(t) or a frequency-domain representation X(f). When emitted from the TX-antenna, the wireless channel alters the signal as it propagates to the RX. As the channel response has respective representations h(t) and H(f), the receiver signal can be recovered through convolution y(t) = h(t) * x(t) in the temporal domain or multiplication Y(f) = H(f) · X(f) in the frequency domain.

    As a circular array antenna (radius = 24 cm) with 96 elements was used as a receiver, the measured channel frequency responses for all elements can be downloaded in a single data file (and readily converted to the channel temporal responses, if desired) by following the download instructions below. In each of the four buildings, there are 50 TX-sites with location indexed on a building map by numbers on colored squares. Each TX-site has a matching RX-site shown as a circle with matching color on the map. The line from the circle marks the first element at 0° and the arrow indicates the angle orientation. Sample data file / Diagram of UCA RX shows a sample data file and the diagram of the UCA. Each data file also provides the ground-truth distance, angle, and number of walls between the transmitter and the center of UCA receiver. The figures on the sidebar below show the temporal and frequency responses between the TX and the first element of the RX. Details of the measurement system and campaign can be found in the following publications:

  • IEEE ICC 2008 / EURASIP JWCN 2008 - Time-of-flight/angle-of-flight extraction in stand-alone location systems
  • IEEE TAP 2009 - UWB-MIMO spatial-temporal channel propagation model

    The closely spaced responses can be used to study the small-scale fading of the channel or to generate the spatial-temporal channel response h(t,θ) or equivalent H(f,θ) particularly useful in designing MIMO systems: the received response y(t,θ) = h(t,θ) * x(t) or Y(f,θ) = H(f,θ) · X(f) is then a function of angle as well.

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