Dataset DOI: 10.5061/dryad.r7sqv9sr3

Description of the data and file structure

This dataset (Aerpaw_PawPrints_Packapalooza_Helikite.zip) contains cellular LTE measurements from an Android phone carried by a tethered HeliKite, over a duration of approximately one and a half hours, within the North Campus of NC State University. The Helikite eventually rose to an altitude of 120 meters.

RSRP, RSRQ, and RSSI values of public AT&T networks are shared, along with their physical cell ID. A GPS logger onboard the HeliKite recorded the latitude, longitude, and altitude. Radio and GPS measurements were recorded at one-second intervals and merged based on the timestamp.

Dataset Content:

The dataset is shared in the form of a zip file, named aerpaw_pawprints_packapalooaza_helikit.zip, containing the following folders:

• Logs: Contains the pawprints_4G.csv raw log file with the KPIs
• KMLs: Contains representative KML files, indicating variation in RSRP and RSRQ with location 
• Results: Contains .png images of the representative KMLs and some Matlab plots of variation in KPIs with time and altitude.

KPI Logs:
The Logs folder within the dataset contains timestamped 4G cellular KPIs in "pawprints_4G.csv". KPIs were logged at intervals of 1 second. KPIs of differtent AT&T cell towers, identified by their PCI, are logged in separate rows.

A column, named "is_connected", indicates whether the UAV was connected to the corresponding PCI at each row. Users of the dataset can filter using this row to analyze KPIs only for the connected cell or filter using the "pci" column to analyze a specific cell.

Each row contains the following KPIs:

• Timestamp of the measurement row:
  • Column name = timestamp. Units = milliseconds.
  • Unix timestamp of the measurement in milliseconds elapsed since the Unix epoch (Jan 1, 1970).
• Relative time since start of measurement:
  • Column name = rel_time. Units = seconds.

• Helikite longitude:
  • Column name = longitude. Units = degrees. 
• Helikite latitude
  • Column name = latitude. Units = degrees. 
• Helikite altitude above ground:
  • Column name = altitude. Units = meters. 
• Physical cell identity (PCI): 
  • Column name = pci. No units.
  • Indicates the physical layer cell identity of the cell.
• Cell Identity (CI): 
  • Column name = ci. No units.
  • Unique global identifier for a cell sector. 
• "Connected" flag:
  • Column name = is_connected. Units = 1 or 0.
  • An integer flag, which indicates if the UAV was connected to the corresponding PCI at the corresponding timestamp. 1 indicates connected. 0 indicates not connected. Users can filter on this field to only choose log rows corresponding to the connected PCI, e.g., to analyze the distribution of the connected RSRP.
• Tracking area code (TAC):
  • Column name = tac. No units
• EARFCN (E-UTRA Absolute Radio Frequency Channel Number):
  • Column name = earfcn. No units

• Received Signal Reference Power (RSRP): 
  • Column name = rsrp. Units = dBm.
• Received Signal Strength Indicator (RSSI): 
  • Column name = rssi. Units = dBm. 
• Reference Signal Received Quality (RSRQ):
  • Column name = rsrq. Units = dB. 
• Arbitrary Strength Unit (ASU):
  • Column name = asu. No units.
  • An integer mapping of signal strength from 0 to 97, as specified in 3GPP TS 27.007. Higher values indicate better signal strength. The value of 0 maps to RSRP below -140 dBm and the value of 97 maps to RSRP above -44 dBm. ASU = RSRP + 140 
• Timing advance (TA): 
  • Column name = ta. No units.
  • An instruction sent from base stations to cellular users, providing them with a specific timing offset, to ensure that the uplink signals arrive in time at the base station. Adjusted in relation to the distance of the user from the base station.

KMLs:

KML files for RSRP, and RSRQ are included for the connected cell, named packapalooza_rsrp.kml and packapalooza_rsrq.kml respectively. It is also possible to generate KMLs of KPIs per cell tower.

Representative Results:

PNG files showing the variation in RSRP, RSRQ, and LTE signal quality (as determined by RSRP and RSRQ thresholds) with UAV location are included in the ./Results folder. Details are as follows:

helikite_rsrp_rssi_vs_time.png: Variation in HeliKite RSRP and RSSI with time and altitude

helikite_rsrq _vs_time.png: Variation in HeliKite RSRQ and RSSI with time and altitude

helikite_rssi.png: Variation in HeliKite RSSI with its position, as visualized on Google Earth using a KML file.

helikite_rsrq.png: Variation in HeliKite RSRQ with its position, as visualized on Google Earth using a KML file.

helikite_rsrp.png: Variation in HeliKite RSRP with its position, as visualized on Google Earth using a KML file.

helikite_quality.png: Variation in HeliKite's received signal quality (calculated using LTE thresholds on RSRP and RSRQ) with its position, as visualized on Google Earth using a KML file.

Code/software

The KMLs can be opened with Google Earth. 

The .csv log files can be analyzed using MATLAB or the Python pandas library.