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MeasuredCIRDataSet

Measured Channel Impulse Response Data Set

This site provides access to over 9300 measured channel impulse responses in a 44-node wireless network. Multiple measurements are provided for each of the 44*43=1892 pairwise links between the nodes. The data is freely available for non-commercial use.

Example

An example of the measured channel impulse responses is shown in Figure 1.


Figure 1: Example channel impulse response measured on link from Tx at location 1 and Rx at location 16.


Measurement Campaign

The measurement transmitter was a 40 MHz chip rate DS-SS signal generator. The center frequency was 2.443 GHz. The receiver was a software radio (Sigtek model ST-515) designed to receive the signal, cross-correlate it with the known transmitted signal, and thus have a high-bandwidth estimate of the (complex) channel impulse response.

The transmitter and receiver were closely synchronized, to within 1-2 nanoseconds of each other, using GPS and rubidium oscillators, and extensive re-calibration. The data thus allows you to know the actual propagation delay of the RF signal.

The measurement campaign consisted of 44 node locations, as shown in Figure 2. The measurements were conducted in a standard office area, as shown in Figure 3.


Figure 2: Map of node locations used in the campaign on top of the cubicle map.

Figure 3: Measurement area photo.


By moving the transmitter and receiver between node locations 1-44, we measured every link in the network.

Details are provided in reference [1].

Download Data

Data is saved in Matlab .mat format (using Matlab 6.5). There are two .mat files provided.

  • savedSig.mat: This file contains three variables:
    • savedSig
    • savedStartTime_ns
    • delta_t
  • deviceLocs.mat: This file contains one variable:
    • deviceLocs.mat

We also provide an example Matlab script useful as an example of how to access and plot the CIR data:

  • Plot_Sig_From_Meas.m

These three files are contained in one .zip file.

Download All Files

Data Format

In general, savedSig is a 2-D Matlab cell array. Element savedSig{i,j} accesses the measurements for link with transmitter at i and receiver at j, where i and j are between 1 and 44. The measurements themselves are stored in a matrix, with each row representing one CIR. There are typically five rows in the matrix, although sometimes fewer.

To save space, only the non-noise part of the CIR measurement is provided. Matlab cell array savedStartTime_ns{i,j}(k) provides the delay of the first sample of the kth measured CIR of link (i,j). The sampling period is delta_t.

The script Plot_Sig_From_Meas.m contains more detailed descriptions of the data.

Applications

The data set was used in [2] to test a temporal link signature-based location distinction algorithm. It can be used for TOA and RSS measurements [1], as well as to test other time-synchronization algorithms.

Restrictions

The data set is not for commercial use. Please cite the appropriate references, and acknowledge Motorola Labs, Florida Communications Research Lab, and the University of Utah, when using the data set in published work.

References

  1. N. Patwari, A. O. Hero, M. Perkins, N. S. Correal, R. J. O'Dea, Relative Location Estimation in Wireless Sensor Networks, IEEE Transactions on Signal Processing, vol. 51, no. 8, August 2003, pp. 2137-2148.
  2. N. Patwari and S. K. Kasera, Robust Location Distinction using Temporal Link Signatures, in Proc. of 13th Int. Conf. on Mobile Computing and Networking (Mobicom-07), pages 111-122, Montreal, QC, Sept 12, 2007.
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Page last modified on September 14, 2007, at 06:12 AM MST