Joint relay selection and adaption of modulation, coding and transmit power for spectral efficiency optimisation in amplify‐forward relay network

Performance Improvement of Non-Regerative Cooperative Relay Networks with Optimal Power Allocation and Adaptive M-QAM/M-PSK Modulation Over Generalized Fading Channels

“…, where the CDF term can be evaluated efficiently using (8) given that the MGF of γ is available or alternatively, by setting 0 s = in our derived closed form marginal MGF expression in (6). Although note that we have derived a closed-form expression of the marginal MGF in (6) for the case of i.n.d Nakagami-m fading (positive integer m) from (5), it is very simpler to program and evaluate the desired outage probability using (8) (in conjunction with (5)).…”

“…Whereas authors in [5] studied the power assignment strategy by considering fixed relay position for incremental selective decode and forward cooperative relay networks over the Rice fading channel in terms of only symbol error rate analysis, but without link adaptation. Authors in [6] studied joint relay selection and adaptive modulation coding in amplify and forward relay network with Rayleigh fading channel. The ABER performance of a cooperative relay network with BPSK modulation in a Nakagami-m fading channel was investigated in [7], however the authors did not consider higher constellation size or adaptive modulation schemes.…”

Optimised secure transmission through untrusted AF relays using link adaptation

“…In our designed scheme two relays cooperate in transmission where although none of which is able to properly detect the signal but the received signal after maximum ratio combining is properly detected at the receiver. As numerical evaluations show, considering physical layer security results in a decrease in the average transmission rate compared to what is achieved by optimised joint relay selection and link adaptation scheme by Taki and Sadeghi (2014). But the performance degradation is acceptable at the cost of providing confidentiality of the information.…”

“…In Taki's (2013) article, a transmission scheme is designed to optimise spectral efficiency in an AF-relay network using AMC and continuous power adaptation. Joint relay selection and discrete link adaption schemes for AF relay network are designed by Taki and Sadeghi (2014). A considerable outperformance is seen by continuous power adaptation compared to constant power transmission.…”

“…The design goal is to maximise the average spectral efficiency between the transmitter and the receiver, while (1) individual average power constraints are considered for the transmitter and each of the relays, (2) in order to have proper detection of information, BER at the receiver is lower than a specific level, (3) in order to keep confidentiality of information against hears of relays, detection BER at the relays is more than a specific level. As is shown by Taki and Sadeghi (2014), in a two-hop AF relay network with several relays, the optimum way is that for each channel state a single relay is selected for cooperation and others are turned off. However, obviously secure relaying is impossible with a single relay, as that relay has definitely better received SNR than the receiver.…”