Time-based and Low-Cost Bandwidth Estimation for IEEE 802.11 Links
This paper presents a practical and low-cost approach to estimate the maximum achievable wireless link bandwidth based on the prevailing link conditions in an IEEE 802.11 network. This approach works by observing the number of bits successfully delivered over a link, divided by the corresponding channel occupancy time. The method is passive and does not introduce any extra overhead on the channel, and is based on the timing model of the IEEE 802.11 MAC layer. All required parameters are obtained locally at the sending node from the MAC layer. We evaluate the accuracy of the proposed method via a full implementation and experiments on our conducted testbed, which provides a more controlled environment and increased repeatability of experiments, compared to over-the-air wireless testbeds. The experiment results show that our method can accurately estimate the link bandwidth with both saturated and low traffic load across links with different transmission rates and link qualities. In addition, results also show that our method is able to track the link bandwidth as its link quality changes.
Keywords: wireless networks, routing protocols, link quality metrics