Reconstruction of UWB Indoor Radio Wave Propagation
Within the "whyless.com" project a number of UWB indoor radio channel measurements have been performed inside the premises of IMST GmbH. The measurement bandwidth was 1 to 11 GHz [1].
The video clips below show the reconstruction of waves that propagate through an indoor environment (office room); the waves are reconstructed over an area of 30 cm x 150 cm at 1.5 m height above the floor, i.e., the clips show a two-dimensional cut through the three-dimensional waves.
The reconstruction is entirely based on measurements and illustrates the fact that several individual echoes, which are embedded in dense multipath, may be recognised and traced due to the high bandwidth. The bandwidth of 10 GHz corresponds to a temporal resolution of app. 100 ps, which in turn corresponds to a spatial resolution of app. 3 cm (the resolution is degraded somewhat due to the application of a frequency domain window for sidelobe reduction).
The displayed quantity is the modulus of the space-variant baseband impulse response of the radio channel, i.e. |S21(x,y,t)| of the twoport formed by the connectors of the Tx and Rx antenna, for positions (x, y) of the Rx antenna in the rectangular area under consideration. Consequently, the waves shown are waves of locally averaged e.m. fields, where "local average" corresponds to the mapping of field strengths to antenna connector signals as performed by the antennas. This gives an approximation of the underlying radio waves. Each clip shows the waves on a logarithmic (magnitude) and/or absolute scale.
Comments and questions are welcome.
| [1] | J. Kunisch and J. Pamp, “Measurement results and modeling aspects for the UWB radio channel,” Proc. IEEE UWBST 2002 Conf., Baltimore, May 2002. |
| Scenario |
File |
Description |
|
Office-LOS Measurement |
Large (absolute and magnitude) (mpeg1, 4.7 MB) 2D with floor plan (magnitude) 3D view into room (magnitude) (mpeg1, 4.7 MB) |
Tx and Rx in the same office room. Delay 9.5 ns: The wavefront corresponding to the direct path (direct path echo) arrives at the top left corner. 12.6 ns: The floor reflection echo (via Tx-floor-Rx path) arrives (top left corner). 14.2 ns: The ceiling reflection echo (via Tx-ceiling-Rx path) arrives (top left corner). 20.1 ns: A scattered back reflection echo(s) arrives (bottom left corner). 23.1 ns: Another back reflection arrives (bottom middle). |
| Office-NLOS Measurement |
Large (absolute and magnitude) (mpeg1, 6.5 MB) 2D with floor plan (magnitude) 3D view into room (magnitude) |
Tx and Rx in the same office room, line of sight obstructed
by two metal cabinets (standing side by side, total size of obstruction
1.78 x 0.42 x 1.96 m). Left hand side face standing at wall.
Delay 9.7 ns: An wavefront diffracted around the right hand side edges/face of the cabinet (via Tx, cabinet wall, Rx path) arrives (top right corner). 10.5 ns: A double wavefront arrives (presumably diffracted over top edges/face of the cabinet) (top left). 11.9 ns: A wavefront (presumably diffracted around left hand side edges/face of the cabinet) arrives (top left corner). 12.5 ns: A number of further wavefronts (presumably diffracted around cabinet) arrives (top right corner). 13.6 ns: A strong wavefront corresponding to propagation over the cabinet arrives; dense multipath signals follow. 25 ns: A single wall reflection wavefront (via Tx-wall-Rx path) arrives (top right corner) (cf. LOS case @ 15.6 ns). 27.8 ns: Another wavefront arrives from the same direction, (presumably via Tx-floor-wall-Rx path) (top right corner). 30.8 ns: Yet another wavefront from the same direction arrives (top right corner). |