Exploiting reciprocal channel estimations for jamming to secure wireless communications

The work in this manuscript proposes to enhance the secrecy level of wireless systems through the use of a jamming technique that uses uncorrelated reciprocal channel estimations from the legitimate channel as a common random source to select discrete jamming signals in both sides of the legitimate link. After that selection, these jamming signals are combined with data at the legitimate transmitter, being posteriorly canceled at legitimate receiver. In order to improve the secrecy level of the proposed scheme, an algorithm that efficiently combines data with discrete jamming signals is also developed. The comparison of the scheme proposed in this manuscript with a jamming technique discussed in [13], allowed to verify that the proposed scheme achieves a level of secrecy that does not fall to zero with the signal-to-noise ratio (SNR) increase, instead it saturates in a positive level becoming independent of the power conditions. The results have also showed that making an efficient selection of the jamming signals that will be combined with data, the level of secrecy can be further improved.