Towards LTE-U Interference Detection, Assessment and Mitigation in 802.11 Networks using Commodity Hardware

TL;DR

WiPLUS is a system that passively detects LTE-U interference in WiFi networks using MAC layer data, enabling accurate assessment and mitigation without hardware modifications.

Contribution

It introduces a novel, hardware-agnostic method for LTE-U interference detection and mitigation using commodity WiFi hardware and MAC layer information.

Findings

Accurately estimates medium airtime with less than 3% RMS error for downlink.

Works with commodity WiFi APs without client modifications.

Provides timing info for LTE-U ON/OFF phases for interference mitigation.

Abstract

We propose WiPLUS -- a system that enables WiFi to deal with the stealthy invasion of LTE-U into the frequency bands used by WiFi. Using solely MAC layer information extracted passively, during runtime, out of the hardware registers of the WiFi NIC at the WiFi access point, WiPLUS is able to: i) detect interfering LTE-U signals, ii) compute their duty-cycles, and iii) derive the effective medium airtime available for each WiFi link in a WiFi Basic Service Set (BSS). Moreover WiPLUS provides accurate timing information about the detected LTE-U ON and OFF phases enabling advanced interference mitigation strategies such as interference-aware scheduling of packet transmissions, rate adaptation and adaptive channel bonding. WiPLUS does not require any modifications to the WiFi client stations and works with commodity WiFi APs where it has a simple software installation process. We present the design, the implementation details and the evaluation of the WiPLUS approach. Evaluation results reveal that it is able to accurately estimate the effective available medium airtime for each link in a WiFi BSS under a wide range of LTE-U signal strengths with a root-mean-square error of less than 3% for the downlink and less 10% for the uplink.