Anti-collision Tags for Backscatter Sensor Networks

This work analytically quantifies and attempts to alleviate the collision induced by a number of tags that operate via backscatter communication, i.e. modulate the reflection of a common carrier transmitted by a central hub. For omni hub antenna, it is shown that acceptable anti-collision performance can be engineered only when appropriate modulation at each tag is employed. When a beamforming hub antenna with moderate main lobe width and side lobe level (SLL) is instead used, the aggregate communication bandwidth is significantly reduced, or equivalently, the aggregate number of tags is amplified. Analytical results apply to general forms of backscatter communication, potentially useful in classic RFID systems.