LTE filtering on Wi-Fi Access Points

Outdoor Wi-Fi networks are seeing large rollouts in recent years, particularly those managed by Service Providers, Carriers and Governments. These networks are being rolled out to meet the ever-increasing demand for bandwidth by people on the go. There is another technology: LTE, in a nearby spectrum that is also seeing similar adoption and there are some interesting challenges showing up in the field with co-located equipment.

2.4GHz Wi-Fi Co-existence bcomes an issue with nearby LTE cellular Micro and Pico base stations in the LTE, E-UTRA Frequency Bands 7, 38, 40, and 41. These four bands are the closest to the unlicensed 2.440-2483.5MHz band used by Wi-Fi.

Wi-Fi LTE co-existence bands

The near overlap of the typically high powered LTE base stations can have a very detrimental effect on Wi-Fi AP performance, and to help mitigate this Cambium cnPilot outdoor Wi-Fi access points include hardware LTE filters.

LTE filters on the cnPilot e700LTE filters on the cnPilot e700

These filters play a critical role in ensuring Wi-Fi services provided by the cnPilot APs such as e500, e501S, e502S, e700 are not impacted by any nearby LTE devices. In addition to real-world performance, the improvements from these filters can also be seen in our own lab tests where the Wi-Fi performance with and without filters is dramatically different, especially as the signal strength of the LTE interference is increased:

2.4Ghz performance with and without LTE filters at 2390MHz2.4Ghz performance with and without LTE filters at 2390MHz

2.4Ghz performance with and without LTE filters at 2506MHz

For more details check out our  Wi-Fi-LTE co-existence solution paper