Device for backscatter communication

摘要

Backscatter communication includes receiving electromagnetic energy from a base station and encoding first data and second data. The first data is encoded at a first frequency by adjusting a radar cross-section of a device to modulate the electromagnetic energy reflected back to the base station. The second data is encoded at a second frequency by limiting the adjusting of the plurality of radar cross-sections to either a first subset or a second subset of the plurality of radar cross-sections for a length of time. The second frequency is lower than the first frequency.

主权项

1. A mobile device comprising:
an antenna configured to receive electromagnetic energy from an RFID base station; modulation circuitry coupled to modulate the antenna between a plurality of impedance values to change a radar cross-section of the mobile device for communicating with the RFID base station via backscattering of the electromagnetic energy; and an encoding module coupled to encode first data at a higher frequency by directing the modulation circuitry to select between the plurality of impedance values and further coupled to encode second data at a lower frequency by directing the modulation circuitry to select among either a first subset or a second subset of the plurality of impedance values for a length of time, wherein a first data state of the second data is represented by selecting among the first subset during the length of time, and wherein a second data state of the second data is represented by selecting among the second subset during the length of time.