A MAC Protocol for MIMO Based IEEE 802.11 Wireless Local Area Networks

An increasing number of wireless devices and services imposes higher demands for wireless networks' capacity. Likewise, contemporary bandwidth requirements of each user in the network rise significantly, being a mixture of traffic types such as Web surfing, file transfer protocol (FTP), video, video-teleconference, and voice. Multiple input-multiple output (MIMO) techniques are recognized as methods that can meet these requirements, since they significantly increase the capacity of wireless networks, without additional bandwidth or transmission power. With a MIMO physical layer (PHY), the transmission channel gets a layered structure. Consequently, support from higher layers with a cross-layer approach that provides efficient management of the channel's spatial layers, can significantly increase the network's performance on both link and system level. In this paper a high capacity medium access control (MAC) protocol for MIMO support is presented. The proposed protocol is based on IEEE 802.11 standard, and provides a flexible and scalable support for multiple antenna terminals, backwards compatible with legacy stations.