Implementing high throughput group-based MAC for WLANs

The IEEE 802.11n-2009 based Wireless Local Area Networks (WLANs) standard presents very high data rate at the physical layer and seeks to attain a throughput at the Medium Access Control (MAC) layer that is higher than 100 Mbps. The mechanism of frame aggregation and Block-ACK frames are implemented to increase the MAC efficiency. However the standard does not introduce a mechanism to reduce the probability of collision. Where, with high data rate, an AP would able to serve more number of stations, which results in a high collision rate. This paper proposes a Group-based MAC (GMAC) scheme that minimizes the probability of collision and also applies frame aggregation to improve the efficiency. Here, grouping the contending station in such a way that each group has one station that is the group leader. This means that only the leader stations contend, hence, reduces the probability of a collision. We evaluate the performance of our proposal with analytic result. The result shows that GMAC attain a high throughput, high fairness, low delay and attains a high performance with high data rates.