## 3 LoRaWAN Networking  
With its star-of-stars network structure, LoRaWAN allows for secure bidirectional communication in both directions. Although LoRa/LoRaWAN technology offers many advantages in terms of low bit rate and power consumption, wide coverage, simplicity, the possibility of deploying a private network, security, and ease to manage due to its star-of-stars topology, recent studies have highlighted a number of potential issues with LoRa/LoRaWAN networks, particularly in terms of scalability in large-scale scenarios. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Property or** & **NB-IoT** & **SigFox** & **Telensa** & **Ingenu RPMA** & **LoRa** \\ \hline \multirow{2}{*}{Standard} & 3 GPP Release 13 & \multirow{2}{*}{SigFox and ETSI LTN} & \multirow{2}{*}{Telensa and ETSI} & \multirow{2}{*}{RPMA and IEEE 802.15.4 K} & \multirow{2}{*}{LoRa Alliance} \\  & & and 14 & & & \\ \hline \multirow{3}{*}{Frequency band} & Licensed & Sub-GHz ISM & \multirow{3}{*}{Sub-GHz ISM} & \multirow{3}{*}{Sub-GHz ISM} & \multirow{3}{*}{EU: 868 MHz} \\  & 7–900 MHz & EU: 868 MHz & & & \\  & US: 902 MHz & & & & \\  & & US: 915 MHz & & & \\  & & AS: 430 MHz & & & \\ \hline \multirow{3}{*}{Bandwidth} & 180 kHz & 100 or 600 Hz & \multirow{3}{*}{100 kHz} & \multirow{3}{*}{125,250,500 kHz} \\  & & DL:1.5 kHz & & & \\ \hline \multirow{3}{*}{Modulation} & DL: QPSK & UL: UNB DBPSK & \multirow{3}{*}{UNB 2-PSK} & UL: RPMA- & \multirow{3}{*}{CSS} \\  & \(\pi/2\)-BPSK, QPSK & DL: GFSK & & & \\  & & & DL: CDMA & & \\ \hline \multirow{3}{*}{MAC} & TDMA-based MAC & ALOHA MAC & n/a & TDMA-based MAC & LoRaWAN/ ALOHA- \\ \hline \multirow{3}{*}{Protocol ownership} & Standard & Proprietary & Standard & Proprietary & Partially proprietary \\ \hline \multirow{3}{*}{Data rate} & UL: 64 kbps & UL: 100 or 600 bps & UL: 62.5 bps & UL: 624 kbps & LoRa: 0.3–37.5 kbps, \\  & DL: 25 kbps & DL: 600 bps & DL: 500 bps & DL: 156 kbps & FSK: 50 kbps \\ \hline \multirow{3}{*}{Range} & Urban: 1.5 km & Urban: 3–10 km & Urban: 3 km & Urban: 15 km & Urban: 5 km \\  & Rural: 20–40 km & Rural: 30–50 km & Rural: 16 km (NLOS) & Rural: 48 km & Rural: 45 km \\ \hline \multirow{3}{*}{Link budget (dB)} & Urban: 189 & \multirow{3}{*}{13} & EU: 162 & EU: 161 & EU: 168 & EU: 151 \\  & & US: 146 & US: 149 & US: 180 & US: 171 \\ \hline \multirow{3}{*}{Max. Payload size (bytes)} & \multirow{3}{*}{13} & UL: 12 & \multirow{3}{*}{65k} & EU: 624 kbps & \multirow{3}{*}{250} \\  & & DL: 8 & & & \\ \hline Tx power (dBm) & 35 & 24 & 14 & 21 & 21 \\ \hline \multirow{3}{*}{Security} & \multirow{3}{*}{L2 security} & No or encryption at & \multirow{3}{*}{Yes} & AES 256 b & AES 128 b \\ \hline Interference & Low & Very high & Very high & Low & Very high \\ immunity & & & & & \\ \hline Adaptive data rate & No & No & No & Yes & Yes \\ \hline Localization & No & Yes (RSSI) & No & No & Yes (TDOA) \\ \hline Topology & Star & Star & Star or tree & Star or tree & Star-of-stars \\ \hline Energy consumption & Low & Very low & Low & High & Very low \\ \hline Link symmetry & No & No & No & No & Yes \\ \hline Allow private & No & No & No & Yes & Yes \\ \hline Over the air updates & No & No & Yes & Yes & Yes \\ \hline \multirow{3}{*}{Error Correction} & CRC & UL: CRC-16 & \multirow{3}{*}{Yes} & CRC & FEC and CRC-8/16 \\  & & DL: CRC-8 & & & \\ \hline \multirow{3}{*}{Channel or orthogonal signal} & \multirow{3}{*}{12 carrier} & \multirow{3}{*}{360} & \multirow{3}{*}{multiple} & EU: 10 & \multirow{3}{*}{US: UL 64+8, } \\  & & & & & \\  & & & & & \\ \hline Nodes per gateway & 52,000 & \textgreater{}1,000,000 & 5000 & 500,000 & \textgreater{}1,000,000 \\ \hline Cost & Moderate & Moderate & High & Low & Very low \\ \hline \hline \end{tabular}
\end{table} 
Table 1: LPWAN technology comparison. LoRaWAN is a cloud-based MAC layer networking protocol that is designed and maintained by the LoRa Alliance to define the upper layers of long-range wide-area networks with a LoRa physical layer.