Interference detection

Abstract

Wireless access point devices having wireless networks operating in accordance with 802.11b / g 2.4Ghz Wi-Fi can be affected by out-of-band interference caused by LTE small cell devices such as macrocells and femtocells. The wireless access points detect such interference devices using a flow processor to monitor the characteristics of data flows of devices connected to the wireless access point to determine whether they are LTE cells based on MAC address matching or the termination of a flow at a known mobile network operator gateway. When a cell is detected, the wireless access point scans for neighbouring wireless networks of neighbouring wireless access points which may also be affected by the interference generated by the LTE cell. A management server processes information relating the LTE cell and the neighbouring wireless networks and generates a mitigation action to change the operational behaviour of the wireless access point and any neighbouring wireless access points to mitigate the effect of the detected interference device on the wireless networks.

Description

[0001] The present invention relates to wireless communications, and in particular, to methods and apparatus for detecting the presence of potential sources of interference and taking countermeasures. Background technique [0002] In wireless communications, the IEEE 802.11 family of standards related to "Wi-Fi" is now a popular system that allows devices to communicate wirelessly using radio wave transmission. A cluster of devices all communicating via a common wireless access gateway is called a wireless local area network (WLAN). [0003] Wi-Fi communication is licensed to work in two frequency bands 2.4Ghz and 5Ghz in the radio spectrum. Currently, most devices are only able to work in the popular 2.4Ghz spectrum band, while more newer devices also work in the generally less crowded 5Ghz band. [0004] In 2.4Ghz Wi-Fi, the spectrum between 2402Mhz and 2472Mhz is divided into several channels, each channel has a center frequency that is 5Mhz apart from its neighbors. Howe...

AI Technical Summary

Problems solved by technology

For some Wi-Fi receivers with poor out-of-band rejection (especially older hardware that was released when the surrounding spectrum was largely unused), LTE transmissions in these bands can lead to relatively low performance impacts on Wi-Fi throughput. adjacent channel interference

The main impact is to cause a reduction in the sensitivity of the Wi-Fi receiver, resulting in reduced Wi-Fi range and reduced throughput within range

In worse cases, i.e., where the LTE transmit power is high (eg, >15dBm) and the LTE transmitter is close to the Wi-Fi site (eg, <1m), the LTE transmission can raise the noise floor above the carrier detection level. A listening threshold such that the Wi-Fi transmitter cannot sense that the channel is idle, and thus never transmit, which can lead to the destruction of the Wi-Fi link and possible disconnection

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