1. To Jam or Not to Jam in Gaussian MIMO Wiretap Channels ?: Invited Paper
- Author
-
Sergey Loyka and Mahdi Khojastehnia
- Subjects
Cognitive radio ,Computer science ,Feasible region ,MIMO ,Artificial noise ,Jamming ,Fading ,Transmitter power output ,Precoding ,Algorithm ,Computer Science::Cryptography and Security ,Computer Science::Information Theory - Abstract
The popular technique of secure signaling over Gaussian MIMO wiretap channels, which makes use of artificial noise (AN) to increase secrecy rates, is considered. First, we briefly review the current state of affairs in this area and then provide new analytical results and insights on the usefulness of AN (jamming) to boost secrecy rates. The settings considered here go beyond the total transmit power constraint and include a number of additional constraints, such as interference (cognitive radio) and energy-harvesting constraints, for which the feasible set is not isotropic anymore so that the standard tools of the analysis cannot be used. By closely examining optimal precoding for the information-bearing and AN signals, we identify a number of cases where it is optimal to transmit no artificial noise at all (so that all the transmit power goes to the information-bearing signal). These cases include a fixed (no fading) MIMO WTC with single eavesdropper (for which we give a direct matrix-theoretic proof using novel matrix inequalities), multi-eavesdropper (com-pound) degraded and reversely-degraded channels, and multi-eavesdropper channels where there exists a dominant eavesdropper (for which we give a precise definition) or when the eavesdroppers collude. To improve secrecy rates by using AN, one has to look elsewhere.
- Published
- 2021