Versatile-Modulation and Megabit-Rate Backscatter System: Design, Implementation, and Experimental Results.

Due to its almost zero power consumption and low hardware costs, backscatter technology has recently gained considerable attention. However, traditional backscatter systems employ basic binary modulations to transmit data at a relatively low rate. In this paper, we introduce VITAS, a new backscatter system that enables the tag to communicate with the transceiver using versatile modulations at a megabit rate. First, we present the design of the tag, which supports both binary and higher-order modulations. We also develop a series of assembly instructions for the tag controller to generate modulated symbols with minimal clock cycles, thereby enhancing the data rate for a given clock frequency. Then, we design the transceiver to coordinate the backscatter communications with the tag. The transceiver incorporates a specific symbol synchronization algorithm to address the accumulated timing errors resulting from the tag unstable clock during high-rate transmission. Furthermore, we fabricate the tag on a four-layer printed circuit board and implement the transceiver on a universal software radio peripheral X310. Finally, we provide experimental results to show that the VITAS system is capable of transmitting QPSK symbols at a maximum rate of 3 Mbit/s while consuming only 9.63 μW (3.21 pJ/bit).