Radio Link Quality in Backscatter Communication

The opportunities that the Internet of Things (IoT) offers impose the need of ultra low-power communication systems. For that, backscatter communication can be used, where the transmitting node consumes only a few tens of micro Watts. This is achieved because the node transmits only by selectively absorbing or reflecting existing RF signals generated by another IoT device. As a consequence, the backscattered signal is considerably degraded. The degradation of the signal along with the interference caused at the receiver by the original RF signal, result in reduced communication range.In the first part of this thesis we experimentally investigated the degradation in the quality of the backscatter radio link. Throughout the experiments we employed the frequency-shifted backscatter communication scheme where the backscatter tag generates its transmission shifted by a frequency offset from the interference of the original RF signals. The experimental results indicate that for frequency offset greater than 10 MHz the interference presented by these RF signals affects less the backscattered signal received 2, 3, or 4 IEEE 802.15.4 channels away