Concurrent Access Control Using Subcarrier Signature in Heterogeneous MIMO-Based WLAN

In recent WLAN standards (such as IEEE 802.11n), MIMO (Multiple Input Multiple Output) is deployed to provide high data transmission rate. It is however challenging to efficiently share the channel resources among different stations/users. In this paper, we study the MAC protocol in heterogeneous MIMO-based WLAN to effectively exploit the capability of concurrent transmission. We propose a novel subcarrier encoding method, which uses frequency signatures to perform the control message exchange between the AP and multiple stations simultaneously. Afterwards, a MAC protocol, HT-MIMO MAC, is presented to support concurrent transmission in both the uplink and downlink directions. HT-MIMO MAC supports link adaptation and is completely compatible with legacy stations. We evaluate the performance of the HT-MIMO MAC protocol and find that it outperforms the existing 802.11 MAC protocol with SU-MIMO and the downlink MU-MIMO MAC protocol in [9] with a remarkable throughput gains up to 86%.