2 research outputs found
Directional Antenna Diversity for Mobile Devices: Characterizations and Solutions
We report a first-of-its-kind realization of directional transmission for smartphone-like
mobile devices using multiple passive directional antennas, supported by only one RF
chain. The key is a multi-antenna system (MiDAS) and its antenna selection methods that
judiciously select the right antenna for transmission. It is grounded by two measurementdriven
studies regarding 1) how smartphones rotate during wireless usage in the field and
2) how orientation and rotation impact the performance of directional antennas under
various propagation environments.
We implement MiDAS using the WARP platform, and evaluate it usmg a
computerized motor to rotate the prototype according to traces collected from smartphone
users in the field. Our evaluation shows MiDAS achieves median of 3dB increase in link
gain. Combined with rate adaptation and power control, MiDAS also improves goodput
and power saving. MiDAS does not require any changes to the network infrastructure,
and is therefore suitable for immediate deployment