# LaRoAwan CubeSat with an Adaptive Data Rate: An Experimental Analysis of Path Loss Link Margin
## 3 IoT Technology Evolution  
IoT has now become a rapidly growing global network for interconnecting devices. Four of the most extensively utilized Low Power Wide Area Network (LPWAN) technologies today are SigFox, Zigbee, NarrowBand-IoT (NB-IoT) and LoRa. These technologies' physical or MAC layer features are compared based on the modulation-coding methods, frequency band, power and other parameters, as well as their performance. Table 2 summarizes the comparison of the different IoT emerging technologies. As per the technology comparison in Table 2, some of these technologies utilized licensed bands, while others utilized unlicensed bands, which everyone can use freely. SigFox technology uses unlicensed industrial, scientific and medical radio (ISM) channels, Binary Phase Shift Keying (BPSK) and Gaussian Frequency Shift Keying (GFSK) for modulation [17]. Because of the modulation utilization at specific frequencies, it is feasible for SigFox to broadcast at 22 dBm and receive at 126 dBm. Due to its capacity to compensate for a frequency drift of up to 30 Hz, SigFox can achieve data rates of up to 600 bits per second, depending on the location. For instance, [PERSON] and [PERSON] proposed network coverage planning for metered devices by using SigFox in the dense urban environment [18]. Their research focused on smart IoT uses for terrestrial connectivity of low-powered devices within the coverage area of 8 km which demonstrated the real time use of SigFox technology. Additionally, the MAC layer protocol can accommodate the delays associated with communication through LEO satellites. Due to SigFox's exclusive right to deploy base stations, other firms are unable to install gateways aboard spacecraft. Another low-powered sensor technology open standard is Zigbee. Zigbee is based on IEEE 802.15.4 for wireless personal area networks, which operates on 868 MHz, 915 MHz and 2.4 GHz, followed by the modulation of DBPSK and QQPSK [19]. As shown in Table 1, \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Ongoing** & **Maximum** & **Minimum** & **RSSI** & **SNR** & **Gateway** & **Data Rate** & **Topology** \\
**Mission/Research** & **Distance (\&m)** & **Elevation** & **(dBm)** & **(dB)** & **Ghee** & **Audio-Tune** & **Echo Response** \\ \hline NORBY [2] & 2622 & 0.88 & \(-\)111.75 & \(-\)7.75 & Single Channel & Auto-Tune & Echo Response \\ Fees [13] & 2554 & 1.09 & \(-\)132.5 & \(-\)9.5 & Single Channel & Auto-Tune & Echo Response \\ Fosssast-2E1 [14] & 2279 & 3.53 & \(-\)133.75 & \(-\)13.75 & Single Channel & Auto-Tune & Echo Response \\ Polylect\_Universe-1 [15] & 1339 & 16.61 & \(-\)130 & \(-\)11.5 & Single Channel & Auto-Tune & Echo Response \\ [PERSON] et al. [16] & 1439.8 & 10 & \(-\)141.6 & - & Single Channel & Fixed & Send/Receive \\ This Research & 2703 & 0 & \(-\)128 & \(-\)21 & 8 Channels & Adaptive Data & Star Topology \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparing this research with past research mentioning network topology and message response using LoRa. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**IoT Technology** & **Range** & **Through-Put** & **Power Consumption** & **Spectrum** & **Modulation** \\ \hline SigFox & 3–50 km & 100 bps & Low & 868,915 MHz & BPSK, GFSK \\ Zigbee & 30–50 m & 10–100 Kbps & Low & 2.4 GHz & DBPSK, QQPSK \\ NB-IoT & 1–10 km & 200 bps & Low & 450 MHz–2.1 GHz & QPSK, OFDM, SC-FDMA \\ LoRa & 2–20 km & 10–50 Kbps & Low & 169 MHz, 433 MHz, 868 MHz, 915 MHz & LoRa, FSK, GFSK \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of different IoT Technologies. Zigbee enables 10-100 Kbps, the promising highest data rate technology amongst other low-powered technologies. However, Zigbee has a limited range of 30-50 m; thus, it is impossible for it to enable the connectivity of ground sensors to low earth orbit spacecraft. Moreover, in order to make use of Zigbee over satellite several steps should be taken. For example, [PERSON] et al.