Adaptive framework for rate adaptation in 802.11n wireless link

Amendments in 802.11n have opened doors to variety of methods to stretch data rates up to 600Mbps. These include spatial diversity, spatial multiplexing both feasible due to MIMO channels, frame aggregation, block acknowledgements, smaller guard interval, channel bonding etc. This paper discusses adaptive framework using of these techniques for efficient rate adaptation of 802.11n. Rate adaptation algorithm have been designed to achieve various objective such as high throughput, low packet error rate, low delay and jitter etc. The paper argues use of SNR to improve throughput depending on the channel condition. SNR is coarse indicator of the rate to be considered for next transmission. The actual rate could be finalized by probing. An algorithm also needs to differentiate between losses due to fading and collision. Authors suggest use of block acknowledgements and RTS/CTS for the same.