LoRaWAN® Gateways: Radio Coexistence Issues and Solutions

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LoRa Alliance ® Whitepaper Page 34 of 49 LoRaWAN ® Gateways Radio Coexistence Issues and Solutions Copyright ©2021 LoRa Alliance, Inc. All rights reserved. www.lora-alliance.org Based on these calculations, we can provide the following recommendations regarding antenna separation of LPWAN gateways: Gateway Type Min. Vertical Separation Min. Horizontal Separation EU868-870 version 5m 200m US902-928 version 1m 20m AU915-928 version 10m 300m AS923 version 50m 1500m The probability of interference may be mitigated, however, by the duty cycle of the LPWAN gateway transmitter (1% to 10%). The probability is therefore low. 5 COLOCATION WITH A HIGH-POWER TRANSMITTER LoRaWAN gateways may be colocated with high-power transmitters. These transmitters could consist of radio broadcasting equipment (FM radio, TV), radars, satellite stations, military applications, etc. All the different uses cases cannot be addressed in this document, but any LoRaWAN deployment must consider all the high- power transmitters in the area. In this section, we are going to consider one of the most critical high-power transmitters, digital terrestrial TV: - DVB-T/T2 in EMEA and APAC regions - ATSC in North America - ISDB-T in Japan and LATAM DVB-T/T2 transmitters are critical due to their high radiated power and also the operating UHF band (470 – 694MHz), which is close to the unlicensed bands used by LPWAN gateways. The DVB-T/T2 transmitters may degrade LoRaWAN gateway receiver performance due to: - Out-of-band spurious emissions falling in the unlicensed band - High-power carrier causing out-of-band blocking If not sufficiently protected (RF filtering), the DVB-T/T2 transmitters may also damage the gateways, and especially the radio front end. 5.1 LoRa/DVB-T ANTENNA ISOLATION The antenna isolation considered in this section is the isolation measured between the LoRaWAN gateway RF port and the DVB-T emitter RF port. Isolation includes, therefore, the LoRa antenna gain, the DVB-T/T2 antenna gain, and the propagation losses. In this section we are going to consider a 6dBi LoRa antenna, as detailed in §3.2.2. DVB-T/T2 emitters antennas have about 5dBi to 15dBi antenna maximum gain. An example of a 15dBi antenna pattern is presented here:

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