CRAWDAD utah/CIR

Measured CIR (Channel Impulse Response) Data Set.

This dataset contains over 9300 measured CIR (channel impulse responses) in a 44-node wireless network.

date/time of measurement start: 2001-03-03

date/time of measurement end: 2001-03-19

collection environment: We recorded 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. This data set was used in [patwari-signatures] to test a temporal link signature-based location distinction algorithm. It can be used for TOA and RSS measurements [patwari-relative], as well as to test other time-synchronization algorithms.

network configuration: 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.

data collection methodology: 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 [map of node locations]. The measurements were conducted in a standard office area. By moving the transmitter and receiver between node locations 1-44, we measured every link in the network.

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.

Traceset

matlab

Traceset of TCP transfers between a car traveling at speeds from 5 mph to 75 mph, and an 802.11b access point.

• file: savedSig.tar.gz
• measurement purpose: Motion Detection, Network Security
• methodology: Environment and System The measured environment, the Motorola Labs, Florida Communication Research Lab facility, is a typical modern office building, with partitioned cubicle offices, metal and wooden furniture, computers, and test and measurement equipment. There are further scatterers near the measurement area, including windows, doors, and cement support beams. There are 44 device locations, shown in [map of node locations], within a 14m by 13m rectangular area. The measurement system is comprised of a direct-sequence spread-spectrum (DS-SS) transmitter (TX) and receiver (RX) (Sigtek model ST-515). The TX outputs a plain DS-SS signal, specifically, an unmodulated pseudo-noise (PN) code signal with a 40 MHz chip rate and code length 1024. The center frequency is 2443 MHz, and the transmit power is 10 mW. The TX and RX are both battery-powered with equipment and batteries placed on carts. Both TX and RX antennas are 2.4 GHz sleeve dipole antennas at 1m height above the floor. The antennas are omnidirectional in the horizontal plane with gain of 1.1 dBi. Note that the cart, the receiver, and objects near to the antenna also affect the antenna pattern, which makes the effective antenna pattern non-omnidirectional. The RX is essentially a software radio which records I and Q samples at a rate of 120 MHz and downconverts them to baseband. - Measurement Collection The campaign measures the channel between each pair of the 44 device locations. There is only one TX and one RX, so one link is measured at a time, and between link measurements, the transmitter or receiver is moved. All 44x43 = 1892 TX and RX permutations are measured. At each permutation of TX and RX locations, the RX measures N = 5 link signatures, over a period of about 30 seconds. A total of 44x43x5=9460 measurements are recorded. Due to the large quantity and manual nature of the experiment, the measurements are completed over the course of eight days. - Radio Channel Dynamics These measurements could not be conducted during normal business hours, and as a result, the physical environment is relatively static. Due to the size of the TX and RX equipment (and the rechargeable marine batteries used to power them) the equipment carts would not comfortably fit into an occupied cubicle along side its occupant. Instead, the measurements were conducted after 6pm. While two or three people were typically working in the measurement environment, the activity level was low relative to daytime. Daytime measurements in a busy office will be an important for future measurement-based verification.
• hole: About 1% of the time, we notice that a link signature has a very low signal-to-noise ratio (SNR). Since measurements are made in the 2.4GHz ISM band, other wireless devices occasionally interfere. Whenever a high noise floor is measured for a link, that measurement is dropped, thus some links have fewer than 5 measurements.

mat Traces 

• savedSig.mat: Matlab trace of measured CIR (Channel Impulse Response) data.
• configuration: The download tarball contains two .mat files (savedSig.mat and deviceLocs.mat) and an example Matlab script (Plot_Sig_From_Meas.m) as an example of how to access and plot the CIR data. The file savedSig.mat is in Matlab .mat format (using Matlab 6.5) and contains three variables: - savedSig - savedStartTime_ns - delta_t
• format: Data is saved in Matlab .mat format (using Matlab 6.5). 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.

• deviceLocs.mat: Matlab trace of device location data.
• configuration: The download tarball contains two .mat files (savedSig.mat and deviceLocs.mat) and an example Matlab script (Plot_Sig_From_Meas.m) as an example of how to access and plot the CIR data. The file deviceLocs.mat is in Matlab .mat format (using Matlab 6.5) and contains one variable: - deviceLocs.mat
• format: Data is saved in Matlab .mat format (using Matlab 6.5). 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.