Decode-and-Forward Relaying Using a Backscatter Device: Power Allocation and BER Analysis

We consider the use of a backscatter device as a relay, and examine a new decode-and-forward (DF) scheme specifically designed for backscatter relaying. In the proposed scheme, the source node transmits continuous-wave (CW) signals to power the backscatter relay in the relay-to-destination phase of the data transmission. We characterise the end-to-end bit error rate (BER) performance for on-off keying (OOK) modulation. In addition, we formulate and solve a power allocation problem at the source node, where the source is subject to a power budget constraint. Numerical results show that the relay-to-destination link is the bottleneck for the end-to-end performance; and that it is essential to allocate most of the source's power budget to its transmission of CW signals to power the relay's transmission.