Ambient Interference Effects in Wi-Fi Networks
Aniket Mahanti1, Niklas Carlsson1, Carey Williamson1, and Martin Arlitt1,2
1 Department of Computer Science, University of Calgary, Calgary, Canada
2 Sustainable IT Ecosystem Lab, HP Labs, Palo Alto, U.S.A.
Abstract. This paper presents a measurement study of interference from six
common devices that use the same 2.4 GHz ISM band as the IEEE 802.11 pro-
tocol. Using both controlled experiments and production environment measure-
ments, we quantify the impact of these devices on the performance of 802.11
Wi-Fi networks. In our controlled experiments, we characterize the interference
properties of these devices, as well as measure and discuss implications of inter-
ference on data, video, and voice traffic. Finally, we use measurements from a
campus network to understand the impact of interference on the operational per-
formance of the network. Overall, we find that the campus network is exposed to
a large variety of non-Wi-Fi devices, and that these devices can have a significant
impact on the interference level in the network.
Keywords: Wi-Fi, Interference, Spectrogram, Duty Cycle, Data, Video, Voice.
Wireless Fidelity (Wi-Fi) networks allow users with wireless-capable devices to access
the Internet without being physically tied to a specific location. Today’s Wi-Fi networks
are not only being used for Web surfing, but also for viewing live video content (e.g.,
live sports and news events) and voice communication (e.g., voice over IP or VoIP).
Many of these services require high quality of service and reliability, which can be
degraded by wireless interference.
Wi-Fi networks employ the IEEE 802.11 protocol, which uses the unlicensed 2.4
GHz Industrial, Scientific, and Medical (ISM) Radio Frequency (RF) band . Since
the ISM band is unlicensed, it is available for use by multiple devices (both Wi-Fi
and non-Wi-Fi), inherently causing interference for one another. The 802.11 protocol is