Microsoft Word - TVLSI_Draft_Final

High-speed wireless network interfaces are among the most power-hungry components on mobile systems that rely on battery for energy supply and passive means for heat dissipation. This is particularly true for MIMO network interfaces which use multiple RF chains simultaneously. In this paper, we present a novel power management mechanism for MIMO network interfaces on mobile systems, called antenna management. The key idea is to adaptively disable some of the antennas as well as their RF chains to reduce circuit power when the capacity improvement of using a large number of antennas is small. The number of active antennas is judiciously determined to minimize energy per bit while satisfying the data rate constraint. We provide both theoretical framework and system design of antenna management: we first present an algorithm that efficiently solves the problem of minimizing MIMO energy per bit, and then offer its 802.11n-compliant system design. We employ both simulation and prototype-based experiment to validate the energy efficiency benefit of antenna management. The results show that antenna management can achieve 21% one-end energy per bit reduction to the front end of the MIMO network interface, compared to a static configuration that keeps all antennas active.