Sensor-Assisted Movement Identification and Prediction for Beamformed 60 GHz Links

Abstract

The 60 GHz frequency band promises very high data rates { in the order of Gb/s { due to the availability of large amounts of bandwidth. High free- space path loss at the 60 GHz frequency band makes it necessary to employ beamforming capable directional antennas to confine signal power in the desired direction. When beamforming is used, the links are sensitive to misalignment in antenna directionality, due to the movement of devices. To identify and circumvent the misalignments, we propose to use motion sensors (i.e., accelerometer and gyroscope) which are already present in most modern mobile devices. By finding the extent of misaligned beams, corrective actions are carried out to reconfigure the antennas. Motion sensors in mobile devices provide means to estimate the extent of misalignments. We collected real data from motion sensors and steered the beams appropriately. The results from our study show that the sensors are capable of detecting the cause of the error as translational or rotational movements. Furthermore it is also shown that sensor data can be used to predict the next location of the user. This can be used to reconfigure the directional antenna to switch the antenna beam and hence avoid frequent link disruptions. This decreases the number of beam searches, thus lowering the MAC overhead.