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 measurement-driven 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 and its antenna selection methods using the WARP platform. We evaluate the implementation using a computerized motor to rotate the prototype according to traces collected from smartphone users in the field. Our evaluation shows that MiDAS achieves a median of 3dB increase in link gain. We demonstrate that rate adaptation and power control can be combined with MiDAS to further improve goodput and power saving. Real-t...

• Type: Conference
• Year: 2010
• Where: MOBICOM
• Authors: Ardalan Amiri Sani, Lin Zhong, Ashutosh Sabharwal
• Keywords: Communications, Directional Antennas, MIDAS, MOBICOM 2010, Passive Directional Antennas