Research on Switching Mechanism for MIMO Mode of 802.11n Wireless Networks

MIMO (Multiple Input Multiple Output) is a key physical mechanism in 802.11n wireless networks, in which there are two MIMO modes: spatial multiplexing and spatial diversity. Due to multiple MIMO modes, rate adaptation is required to optimize the combination of MIMO mode and MCS (Modulation Coding Scheme) by adapting different MIMO modes to different wireless network environments. Therefore, MIMO mode switching scheme is an important building block for rate adaptation in 802.11n networks. In this paper, we first proposed three efficient design guidelines for MIMO mode switching. Then we verified them by designing a simple MImo mode Switching Scheme, called MISS, and implementing it in the Atheros-based device driver. The effectiveness of these three design guidelines is evaluated by the comparison of MISS, Zigzag and no switching mechanism through real experiments in indoor environments.