Collision Avoidance Resource Allocation for LoRaWAN Chinchilla Romero, Natalia Navarro Ortiz, Jorge Muñoz Luengo, Pablo Ameigeiras Gutiérrez, Pablo José LoRa MAC LoRaWAN Capacity Packet error rate Throughput Path loss Data Availability Statement: The data presented in this study are available on request from the corresponding author. Funding: This research was partially funded by the Andalusian Knowledge Agency (project A-TIC- 241-UGR18), the Spanish Ministry of Economy and Competitiveness (project TEC2016-76795-C6-4-R) and the H2020 research and innovation project 5G-CLARITY (Grant No. 871428). The number of connected IoT devices is significantly increasing and it is expected to reach more than two dozens of billions of IoT connections in the coming years. Low Power Wide Area Networks (LPWAN) have become very relevant for this new paradigm due to features such as large coverage and low power consumption. One of the most appealing technologies among these networks is LoRaWAN. Although it may be considered as one of the most mature LPWAN platforms, there are still open gaps such as its capacity limitations. For this reason, this work proposes a collision avoidance resource allocation algorithm named the Collision Avoidance Resource Allocation (CARA) algorithm with the objective of significantly increase system capacity. CARA leverages the multichannel structure and the orthogonality of spreading factors in LoRaWAN networks to avoid collisions among devices. Simulation results show that, assuming ideal radio link conditions, our proposal outperforms in 95.2% the capacity of a standard LoRaWAN network and increases the capacity by almost 40% assuming a realistic propagation model. In addition, it has been verified that CARA devices can coexist with LoRaWAN traditional devices, thus allowing the simultaneous transmissions of both types of devices. Moreover, a proof-of-concept has been implemented using commercial equipment in order to check the feasibility and the correct operation of our solution. 2021-03-25T10:46:41Z 2021-03-25T10:46:41Z 2021-02-09 journal article Chinchilla-Romero, N.; Navarro-Ortiz, J.; Muñoz, P.; Ameigeiras, P. Collision Avoidance Resource Allocation for LoRaWAN. Sensors 2021, 21, 1218. [https://doi.org/10.3390/s21041218] http://hdl.handle.net/10481/67701 10.3390/s21041218 eng info:eu-repo/grantAgreement/EC/H2020/871428 5G-CLARITY http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España MDPI