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LoRaWAN® Gateways: Radio Coexistence Issues and Solutions

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LoRa Alliance ® Whitepaper Page 48 of 49 LoRaWAN ® Gateways Radio Coexistence Issues and Solutions Copyright ©2021 LoRa Alliance, Inc. All rights reserved. www.lora-alliance.org 11 CONCLUSION When colocating a LoRaWAN gateway with high-power transmitters and/or wide-area LTE base stations or medium-range LTE base stations, usage of cavity filters is recommended to mitigate blocker effects, intermodulation effects, and transmit intermodulation. This recommendation is driven by technical aspects, as shown in this application note, but also because the site environment is not under the control of the installer. LTE emitters or DVB-T emitters may be located close to the LoRaWAN gateway site without any possibility to modify it. Using a cavity filter may correct many potential issues. The additional cost of the cavity filter is very low compared with the intervention costs and improvement in quality of service on the installation site. However, cavity filters do not fix all the possible issues. In particular, out-of-band spurious emissions generated by high-power transmitters, wide-area LTE base stations, or medium-range LTE base stations may cause desensitization of the LoRaWAN gateways if minimum vertical and horizontal separation are not respected. These distances are detailed in this white paper and can be roughly summarized by region: • Europe: 2m vertical separation, 300m horizontal separation • North America: 2m vertical separation, 150m horizontal separation • LATAM (AU915-928): 2m vertical separation, 300m horizontal separation. Using UL channels 915 – 922MHz is recommended, rather than 922 – 928MHz. • APAC (AS923): 7m vertical separation, 1500m horizontal separation. Selection of the channels must be carefully considered to optimize the frequency separation with the LTE DL band and mitigate potential desensitization. Moreover, when installing a LoRaWAN gateway with another LPWAN gateway, a minimum vertical separation distance is required, depending on the region: • Europe: 5m vertical separation, 200m horizontal separation • North America: 1m vertical separation, 30m horizontal separation • LATAM (AU915-928): 10m vertical separation, 300m horizontal separation. Using UL channels 915 – 922MHz is recommended, rather than 922 – 928MHz. • APAC (AS923): 50m vertical separation, 1500m horizontal separation. Colocation is therefore not recommended unless using separate channelization. The focus is usually put on the LoRa link, but the GNSS receiver and the LTE backhauling must be also considered. Choice of the antenna is key for better GNSS performance. Separation distance and attenuators (up to 30dB) may be considered to improve the LTE link.

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