Abstract—In this paper, the problem of secure transmission in two-hop amplify-and-forward (AF) systems with an untrusted relay is investigated. To prevent the untrusted relay from intercepting the source message and to achieve positive secrecy rate, the destination-based cooperative jamming (DBCJ) technique is used. In this method the destination sends an intended jamming signal to the relay. T...

Time Division Multiple Access (TDMA) amplify and forward based protocols have been investigated previously by various researchers. However, the gap is still there to investigate the performance of these protocols using inter-relay communication in order to improve the diversity order at destination over Rician fading channel. Therefore, the aim of this paper is to propose TDMA based amplify and...

This paper considers an amplify–quantize–forward (AQF) relay channel withM-ary quadrature amplitude modulation, where the implements amplification for received signal and a uniform quantization each of real imaginary parts amplified version. Two step-size determinant methods affected by power constraint at are proposed deriving mean square error quantized signal. Given step size q...