TOWARDS A HOLISTIC RATE ADAPTION FOR 802.1 1N/AC MIMO SYSTEMS

Abstract

A large number of rate adaptation (RA) schemes have been developed for modern 802.11n MIMO systems. Surprisingly, we found that, in the existing literature there has not been any systematic evaluation of the impact of all the available 802.11n MIMO features, namely frame aggregation (FA), channel bonding (CB), guard interval (GI) and stream modes (SM). In this thesis, we study the impact of these features systematically in order to set or adapt them in a more principled manner and propose a new RA algorithm called Holistic Rate Adaptation (or HiRA) for 802.11n/ac MIMO systems. We found that, in general, by fixing FA to `enabled?, CB to 40 MHz and GI to 400 ns, we can significantly reduce the search space in doing rate adaptation without loss of performance. HiRA also incorporates goodput-based probing to improve probing accuracy, hysteresis to improve stability, and a number of minor innovations. We show that HiRA is able to achieve goodput gains up to 37% in an interference-free scenario, 26% with adjacent channel interference, 27% with co-channel interference, 18% with hidden terminal interference, 11% in a real world mobility scenario and 13% ?in the wild? over the next best performing state-of-the-art RA scheme.