As people become more dependent on wireless devices to send and receive private information (e.g., account information and password, credit card detail for mobile payment, and physiological information for e-health), communication security has already become a crucial concern. Apart from commercial networks, many government and military wireless applications often have very stringent requirements on secure communications. Unlike wired communications where the signal is nicely confined within the dedicated wired line (e.g., cable or optic fiber), the wireless signal sent from the transmitter is broadcast in an open medium. The signal not only reaches the intended receiver, but can also be easily overheard by any unauthorized receiver (called eavesdropper), as shown in the figure above. With an ever-increasing amount of private data being constantly exchanged over the wireless networks, how to protect the confidentiality of such information becomes an important and challenging problem.
Physical layer security is an emerging research area that explores the possibility of achieving reliable data transmission among legitimate network nodes, while possible malicious nodes eavesdropping the communication obtain as little as zero information. The objective of physical layer security is to minimize the amount of confidential information that can be obtained by the eavesdroppers by indirectly manipulating their received signals. This is achieved by exploiting the time-varying properties of the fading channel, smart designs in the channel code, and smart processing of the transmitted signals including friendly jamming signals.
Our research team has been working in the area for more than nine years and made significant contributions in promoting this exciting research area at the international stage. Some of our recent research topics in the area include designing physical layer security techniques in practical wireless scenarios with limited knowledge about the eavesdroppers, smart and low-complexity signaling in multi-antenna secure transmissions. Our research is currently funded by Australian Research Council's Discovery Projects grant.