# LaRoAwan CubeSat with an Adaptive Data Rate: An Experimental Analysis of Path Loss Link Margin
###### Abstract  
One of the challenges of the Internet of Things (IoT) is to provide connectivity to devices around the globe. Long Range (LoRa) is one of the most practical technologies due to its low-power and long-range capabilities to be used by the Low Earth Orbit (LEO) CubeSat. This study aims to evaluate the performance of the Long Range Wide Area Network (LoRaWAN) in receiving uplink messages from ground sensor nodes at an altitude of 550 km with a maximum elevation angle of \(0^{\circ}\). An Adaptive Data Rate (ADR) is applied for the dynamic signal reception with respect to receiving signal strength. In this study, the path loss is simulated using attenuation levels from 30-150 dB to ensure that the signal connectivity success rate is at a minimum elevation angle and to perform the link analysis under various conditions. The results show that the LoRaWAN signals are successfully received with an SNR of \(-21\) at the 150 dB attenuation from the end nodes because of its spread-spectrum technique which allows the system to detect signals under the noise floor. LoRaWAN; CubeSat; slant range; path loss; IoT +
Footnote †: journal: 4  
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One of the challenging parts for the IoT small satellite is the assurance of reception to the sensor devices which are trying to establish a direct connection to the satellite. Several technologies are evolving for IoT services; some are even introduced as real-time solutions. However, when it comes to long-distance low-power communication, LoRa is one of the most promising technologies to overcome this issue. Although extensive research has been conducted along with a brief analysis of LoRa technology, ref. [2] demonstrated NORBY nanosatellite using a LoRa modulation transmitter. NORBY has tested LoRa with different spreading factors and bandwidths. However, NORBY's radio communication used LoRa modulation, which is sufficient for the point-to-point communication relay and cannot be implemented as a star topology while creating sensor networks. In another work [3], KITSUNE CubeSat was a mission designed to develop a sensor network using the LoRa module. KITSUNE used eight separate LoRa transmitter chips to create eight receive frequency receptions which is by far the best solution to create a network of sensors. However, this research was still limited to LoRa modulation and did not use the Adaptive Data Rate (ADR) options. In [4], [PERSON] proposed a CubeSat using LoRaWAN and replicating the LoRa signal by using a USRPB205 mini transceiver which verifies the significance of LoRaWAN architecture for the CubeSats. Nevertheless, replicating LoRaWAN by software-defined radio (SDR) is not cost-effective and will not properly demonstrate the patented Semtech LoRaWAN transmitter. The proposed method in our study illustrates the LoRaWAN architecture in the context of the pertinent literature with a single main transmitter module, RAK2245, along with the ADR option. In addition, the signal receptions are optimized according to the received signal strength, making it perfect for the 1U CubeSat with the minimal necessary power. The key option in LoRaWAN architecture to allow more flexibility in signal processing is using ADR [5]. ADR allows the system to choose the best signal level, even in the worst scenario, in terms of power and Carrier-to-Noise Ratio (CNR). Moreover, in the case of the LEO satellite carrying the LoRaWAN gateway, when the spacecraft is at the maximum distance (at minimum elevation look angle), the signal level will be adjusted as per the reception of the received signal. Meanwhile, when the spacecraft is at the minimum distance from the ground station, the data rate will be adjusted to the maximum, and the time-on-air transmission rate will be improved. In addition, nodes are configured to send only two frames per pass to counteract the Doppler shift.