LoRaWAN® Gateways: Radio Coexistence Issues and Solutions

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LoRa Alliance ® Whitepaper Page 43 of 49 LoRaWAN ® Gateways Radio Coexistence Issues and Solutions Copyright ©2021 LoRa Alliance, Inc. All rights reserved. www.lora-alliance.org to accommodate each country's specifications regarding out-of-band emissions or out- of-band blocker rejection. Examples were provided in §7.1. In LATAM, 915 – 928MHz unlicensed bands are mostly harmonized across countries (Brazil, Argentina, Chile, Colombia, Honduras, Paraguay, Peru, Uruguay, etc.), but there are some exceptions: • Bolivia: 915 – 930MHz • Costa Rica: 920.5 – 928MHz • Curaçao: 920 – 925MHz • Venezuela: 922 – 928MHz Moreover, LTE deployments (bands 5 and 8) may vary by country. Using embedded filters (915 – 928MHz band) would be satisfactory for most of the LATAM countries, but external cavity filters would be more convenient for Venezuela, Costa Rica, and Curaçao. 7.3 IMPACT OF CAVITY FILTERS ON LINK BUDGET Cavity filter losses must be included in the feeder losses in the link budget calculation. The losses obviously have an impact on both the uplink and downlink budget. Depending on the used unlicensed band and country specifications, the cavity filter insertion losses could vary from 0.5dB to 4.0dB. It is quite obvious that a 4.0dB insertion loss could have a huge impact on the coverage area. However, it is possible to mitigate the impact of cavity filter insertion losses by using an appropriate antenna gain. The choice of antenna gain and feeder losses therefore constitutes a trade-off that must be considered before the installation of the gateway. Also, when considering the LoRaWAN DL budget, we need to ensure the gateway is able to transmit at the maximum allowed EIRP, according to the local regulation. The antenna gain therefore must be adjusted depending on: • The gateway's maximum conducted power • The feeder losses including coaxial cable, lightning surge insertion losses, and cavity filter losses • The maximum allowed EIRP, according to the local regulation The following antenna gains are then recommended for different use cases: Gateway Max. Conducted Power Max. EIRP (local regulation) Feeder Losses Recommended Antenna Gain ≤27dBm ≤30dBm ≤1dB 3dBi or 6dBi ≤27dBm ≤30dBm ≥3dB 6dBi ≤27dBm ≥36dBm ≤1dB 9dBi ≤27dBm ≥36dBm ≥3 dB 12dBi ≤30dBm ≤30dBm ≤1dB 3dBi or 6dBi ≤30dBm ≤30dBm ≥3dB 6dBi ≤30dBm ≥36dBm ≤1dB 6dBi ≤30dBm ≥36dBm ≥3 dB 9dBi

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