## 2 LPWAN IoT Technologies
### LoRa  
LoRa is a modulation technology patented and acquired by Semtech Corporation in 2012 for wireless communications [30]. LoRa was created to operate on a sub-GHz frequency, specifically on unlicensed bands such as 915 MHz, 868 MHz, or 433 MHz, in ac  
Figure 6: AP coverage and scalability comparison of Ingenu-RPMA vs. LPWAN. cordance with the regional area regulations. LoRa is a physical layer based on chirp spread spectrum (CSS) modulation, which is not similar to other modulations used in other wireless networks [31]. LoRa was designed to be low-rate, low-power, and transmit with very a long-range in line-of-sight or rural area situations up to 10 or 20 km outdoors as a result of the higher sensitivity of LoRa CSS modulation enabling long-distance connectivity [32]. Its low energy consumption, coupled with long-distance communication, makes LoRa one of the potential candidates of LPWAN technologies for IoT applications [33]. As one of the most significant benefits of LoRa, the great receiver sensitivity is accompanied by an extremely wide communication connection budget. When utilizing LoRa modulation, the typical values of SNR for 10 and 12 spreading factors are \(-20\) dB and \(-15\) dB, respectively, resulting in receiver sensitivities of \(-134\) dBm and \(-129\) dBm, respectively, according to the manufacturer. However, these values are only somewhat equivalent to the average sensitivity of Wi-Fi or Bluetooth receivers, which is typically in the range from \(-40\) dBm to \(-80\) dBm [31]. Different options for orthogonalizing transmissions as much as is feasible are provided by LoRa, such as the carrier frequency (CF), spreading factor (SF), bandwidth (BW), and coding rate (CR), and collision-free communications can be achieved simultaneously. The LoRa radio can transmit with data rates from 250 bps to 5.5 kbps with CSS and up to 50 kb/s with FSK. The SF, CR, BW, and CF are transmission parameters of LoRa, which requires defining their values. The SF is from 7 to 12 as an integer value. There is an inverse relation between the SF and DR by means of increasing the symbol length due to a higher SF, thus decreasing the DR. The lower layers of LoRa are a property by Semtech, while the upper layer is specified by an open standard: LoRaWAN. To connect with a gateway, various end devices can use LoRa modulation, and the LoRa Alliance is developing that open standard [23]. In Table 1, we compare and summarize the considered LPWAN technologies based on various specifications such as the standard, bandwidth, modulation, data rate, range, link budget, maximum payload, power efficiency, security, adaptive data rate, localization, allowance of private networks, availability, and battery lifetime. Hence, each technology can be selected based on the crucial factors of the IoT application and use cases. Solutions such as the RPMA and LoRa can be employed as a private network for the aforementioned applications, whereas Telensa, SigFox, and NB-IoT do not support private network deployment due to the signal coverage being dependent on the base stations of the service provider [8]. Furthermore, the RPMA and LoRa have adaptive data rate features, depending on the distance between device and gateway, that can minimize the time on-air and power consumption in the case of closed end nodes, whereas Telensa, SigFox, and NB-IoT do not support adaptive data rates. In contrast, LoRaWAN by the LoRa Alliance and RPMA by Ingenu have limited investigation of the proprietary LPWAN IoT solutions. LoRa exceeds RPMA in many factors, such as data payload size, link symmetry, and saving energy consumption, as depicted. There are several analytical works on the performance evaluation of data rate adaptation that attempt to represent the optimization issue but are failing miserably. There are a number of publications devoted to the evaluation of LoRaWAN's performance, though they are mostly dedicated to energy consumption, communication range, and network capacity studies.