# Sigfox and LoRaWAN Datasets for Fingerprint Localization in Large Urban and Rural Areas
## 2 Low Power Wide Area Networks
### Sigfox  
Sigfox is a proprietary technology which operates on 868 MHz in Europe and on 902 MHz in the US. Because it uses an Ultra-Narrow Bandwidth (UNB) modulation technique which is called Differential Binary Phase Shift Keying (DBPSK), numerous devices can communicate over ranges up to 10 to 50 km with low power consumption, low-cost hardware setup and easy implementation [9]. However, this modulation technique has a few downsides as well. Due to the narrow bandwidth, the maximum uplink throughput that can be achieved is only 100 bps. Also, regional regulations impose a limited duty cycle of 1%, i.e., 36 s per hour and six seconds per message [12]. Therefore, the daily limit for a Sigfox device equals 140 uplink messages (twelve bytes each) and four downlink messages (eight bytes each). Downlink messages are modulated with Gaussian Frequency Shift Keying (GFSK) and have to be requested by the end-device itself, direct communication between user and device is not possible. To improve the likelihood of successful reception, messages can be sent multiple times (three by default) on random frequency channels. Due to the Sigfox network architecture, messages from a single end-device are received by multiple base stations.  
Since Sigfox uses UNB modulation, timing methods for localization are not a suitable option [13]. Therefore, several other localization methods have been researched. Firstly, Sigfox Geolocation is built on probabilistic distance calculation using RSSI measurements. If a message is received by three or more base stations, the location of the transmitter can be estimated via triangulation. For a location accuracy below 500 m, Sigfox advises to use Sigfox Geolocation as a complementary method to other positioning systems such as WiFi localization or GPS. Secondly, [PERSON] et al demonstrated RSSI fingerprinting as a feasible approach [14]. By providing their Sigfox nodes with GPS modules, the researchers were able to apply fingerprinting to subdivide a large region into classes. Within these classes, location estimation is improved by distance estimation between end-devices and GPS nodes within the same class. However, the radius of a class was limited to 200 m to minimize the location error, as errors of over 60 m were measured for classes with a larger radius. This approach would demand many GPS nodes, which impedes scalability. Lastly, [PERSON] et al implemented a WiFi fingerprinting method in a large urban area [15]. A mobile device was carried around in the city of Antwerp, Belgium while sniffing for WiFi BSSIDs. Every 10 minutes, the device simulated a Sigfox message containing the two BSSIDs with the highest RSSI, which were compared to open source WiFi BSSID databases to obtain a location estimate. This approach led to estimation errors of 23 m to 45 m. However, the Sigfox transmissions had to be dedicated for localization purposes, whereas other methods benefit from the physical characteristics of the Sigfox communication link.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline  & **Sigfox** & **LoRaWAN** & **NB-IoT** \\ \hline \multirow{2}{*}{**Band**} & EU: 868 MHz & EU: 433 and 868 MHz & \multirow{2}{*}{Cellular (LTE)} \\  & US: 902 MHz & US: 915 MHz & \\ \hline \multirow{2}{*}{**Bandwidth**} & 100 Hz & 125–500 kHz & 180 kHz \\ \hline \multirow{2}{*}{**Modulation**} & UL: UNB DBPSK & \multirow{2}{*}{LoRa} & \multirow{2}{*}{BPSK/QPSK} \\  & DL: GPSK & & \\ \hline \multirow{2}{*}{**Data rate**} & UL: 100 bps & \multirow{2}{*}{300 bps–37.5 kbps} & UL: 20 kbps \\  & DL: 600 bps & & DL: 250 bps \\ \hline \multirow{2}{*}{**Max. payload**} & UL: 12 bytes & \multirow{2}{*}{250 bytes} & \multirow{2}{*}{125 bytes} \\  & DL: 8 bytes & & \\ \hline \multirow{2}{*}{**MAC**} & Unslotted ALOHA & \multirow{2}{*}{LoRaWAN} & UL: SC-FDMA \\  & & & DL: OFDMA \\ \hline \multirow{2}{*}{**Topology**} & Star & Star & Cellular network \\ \hline \hline \end{tabular}
\end{table}
Table 1: An overview of three main Low Power Wide Area Network (LPWAN) standards.