Design and Performance of Passive Virtual MIMO in Ambient Backscatter Communication

Ambient backscatter communication (AmBC) is regarded as a cutting-edge technology for the Internet of Things (IoT). In this letter, we explore a low-complexity virtual multiple-input multiple-output (MIMO) architecture for AmBC, which groups a cluster of low-cost single-antenna backscatter devices (BDs) to achieve MIMO transmission rather than using multiple antenna BDs. To overcome difficulties in virtual antenna array (VAA) configuration, a three-step strategy is introduced. After that, a semi-blind channel estimation is combined with a maximum likelihood detector (MLD) for signal detection in the MIMO channel. Numerical simulations show that our proposed strategy is effective and the proposed architectureoutperforms single-antenna AmBC systems under the same signal-to-noise ratio (SNR), which provides better performance to tolerant direct-link interference (DLI).