Linear Precoder Design for an MIMO Gaussian Wiretap Channel With Full-Duplex Source and Destination Nodes

Abstract

Abstract-We consider linear precoder design for a multipleinput multiple-output (MIMO) Gaussian wiretap channel, which comprises two legitimate nodes, i.e., Alice and Bob, operating in Full-Duplex (FD) mode and exchanging confidential messages in the presence of a passive eavesdropper. Using the sum secrecy degrees of freedoms (sum S.D.o.F.) as reliability measure, we formulate an optimization problem with respect to the precoding matrices. In order to solve this problem, we first propose a cooperative secrecy transmission scheme, and prove that its feasible set is sufficient to achieve the maximum sum S.D.o.

Information leakage in bi‐directional IFD communication system with simultaneously transmitted jamming sequence

“…This is because the in-band STR in a multiuser environment causes co-channel interference (CCI) between communicating users [5], or between a backhaul link and an access link [6]. In [10][11][12][13], IFD is applied in a bi-directional IFD (BD-IFD) communication environment where two legitimate users operating in IFD exchange their data. As studied in [7][8][9], a legitimate receiver operating in IFD can transmit a jamming signal while receiving the information transmitted from a legitimate transmitter.…”

“…In the previous studies [10][11][12][13][14][15][16][17] dealing with PHYSEC in BD-IFD communications, it was assumed that the data traffic is the same in both directions of IFD communication links (ie, it is symmetric). However, for practical bidirectional data communication services, the data traffic is typically different in the two directions of data links that is it is asymmetric.…”

“…As reported in [20], which analyzes the traffic of downlink (DL) and uplink (UL) in cellular environment, the DL traffic accounts for 66%-95% of the entire data traffic, whereas the UL traffic accounts for only 5%-33%. In the scenario considered in [10][11][12][13][14][15][16][17], given a traffic asymmetry resulting in a waste of resources in one of the two links, the previous studies provided no guidance as to how to use these remaining resources and how the corresponding performance changes in this case. This is because, in IFD communication, time and frequency resources allocated to the two data transmission links are always the same.…”

“…This is because the in-band STR in a multiuser environment causes co-channel interference (CCI) between communicating users [5], or between a backhaul link and an access link [6]. However, from a PHYSEC perspective, the CCI yielded by the in-band STR of IFD can be used to protect the information of legitimate users from eavesdropping [7][8][9][10][11][12][13][14][15][16][17][18][19]. As studied in [7][8][9], a legitimate receiver operating in IFD can transmit a jamming signal while receiving the information transmitted from a legitimate transmitter.…”

“…When the information of the legitimate transmitter is received by an eavesdropper, this jamming signal causes CCI on the receive (Rx) signal of the eavesdropper, preventing the legitimate information from being | 139 JU et al eavesdropped. In [10][11][12][13], IFD is applied in a bi-directional IFD (BD-IFD) communication environment where two legitimate users operating in IFD exchange their data. In this case, the transmit (Tx) signals of the two IFD legitimate users are received by an eavesdropper simultaneously.…”