Secrecy Throughput Enhancement with ANECE and Multi-Antenna Beamforming in Finite Blocklength

This paper presents a secure downlink communication system where a transmitter with multiple antennas sends information to multiple single antenna users under ultra reliable and low-latency communication (uRLLC) system requirement. To meet uRLLC requirement and provide secrecy against multi-antenna eavesdropper (Eve), transmitter adopts a special channel training scheme called anti-eavesdropping channel estimation (ANECE) as well as a standard transmit beamforming to send secret information in short blocklength regime. Using ANECE, two or more cooperative full-duplex radio devices obtain their receive channel state information (CSI) with respect to each other while preventing Eve from obtaining a consistent estimate of its receive CSI, which improves the secrecy of subsequent transmission of information between the devices. We derive an expression for the average secrecy throughput (AST) of ANECE assisted transmission. This easy-to-evaluate expression of approximated AST in terms of blocklength and various controllable parameters leads to useful insights to maximize AST under uRLLC requirement. Finally, numerical results are presented and discussed.