Improved Energy-Based Signal Detection for Ambient Backscatter Communications

In ambient backscatter communication (AmBC) systems, passive tags connect toa reader by reflecting an ambient radio frequency (RF) signal. However, thereader may not know the channel states and RF source parameters. Thetraditional energy detector (TED) appears to be an ideal solution. However, itperforms poorly under these conditions. To address this, we propose two newdetectors: (1) A joint correlation-energy detector (JCED) based on thefirst-order correlation of the received samples and (2) An improved energydetector (IED) based on the p-th norm of the received signal vector. We comparethe performance of IED and TED under the generalized noise model using McLeishdistribution and derive a general analytical formula for the area under thereceiver operating characteristic (ROC) curves. Based on our results, bothdetectors outperform TED. For example, the probability of detection with afalse alarm rate of 1% for JCED and IED is 22.97% and 5.41% higher,respectively, compared to TED for a single-antenna reader. Using the directinterference cancellation (DIC) technique, these gains are 34.92% and 3.7%,respectively. With a four-antenna array at the reader and a 5% false alarmrate, the JCED shows a significant BER improvement of 28.68% without DIC and48.21% with DIC.