Non-intrusive estimation of available throughput for IEEE 802.11 link

Knowing the available throughput of an IEEE 802.11 link before establishing the connection is beneficial. One usage of such information is the selection of an Access Point (AP) that provides the highest throughput to a user station. In this paper, we propose a scheme that estimates the expected throughput of an 802.11 device in a non-intrusive manner. The proposed scheme does not require any aid from the infrastructure (e.g., AP, router) or other user stations. It does not generate any additional traffic overhead (e.g., probe traffic). Our scheme relies solely on passive sniffing of the on-going traffic for short duration (i.e., less than the typical 802.11 beacon interval). Our scheme works with various 802.11 technologies including 802.11n with frame aggregation and it works even in the situation when it is not possible to sniff complete traffic trace. Our scheme is not affected by the 802.11 security mechanisms, because we only need information from the un-encrypted header part of 802.11 frames. The proposed scheme can be implemented practically in any system and its resource overhead is very low. We have implemented our scheme on a Linux-based notebook and an Android-based smart phone. Experimental evaluation shows that our scheme accurately estimates the expected throughput in various settings.