Leakage rate analysis with imperfect channel state information for cooperative nonorthogonal multiple access networks

Abstract

This paper investigates the imperfect channel state information that is caused by the channel estimation error and feedback delay effects on the leakage rate analysis for the cooperative nonorthogonal multiple access networks. The investigation considers a dual hop one-/two-way nonorthogonal multiple access-based information exchange process with the aid of half-/full-duplex untrustworthy wireless relaying network for the leakage rate analysis. The channel estimation error causes system coding gain losses while the feedback delay does not have any effect on the users' outage performance at untrustworthy relay terminal in low signal-to-noise ratio regimes. Conversely, the channel estimation error effects become negligible while the feedback delay causes system coding gain losses on the users' outage performance at untrustworthy relay terminal in high signal-to-noise ratio. Results also reveal that the untrustworthy relay terminal, which is under the effect of the channel estimation error and feedback delay, is being active between −10 and 25-30 dB. Beyond 25-30 dB, the untrustworthy relay terminal becomes out of order and saturates. The Monte Carlo-based simulation results are in agreement with the analytical and asymptotic derivations. KEYWORDScooperative communications, leakage rate analysis, nonorthogonal multiple access INTRODUCTIONWireless information exchange process has become vulnerable to cyber attacks. This is because of the open medium of wireless communication and broadcasting nature. This results in an information leakage on the legitimate terminals' information exchange process. The literature contains several types of techniques to mitigate the information leakage. Until Wyner's wiretap channels, 1 the secure information exchange processes were compensated with the help of the higher layer encryption techniques, which are data encryption standard (DES), 2 triple data ecryption standard (TDES), 3 Rivest-Shamir-Adleman (RSA), 4 and advanced encryption standard (AES). 5 The drawback of the aforementioned higher level encryption techniques is the receiver needs to have a secret key to decode the cipher text. Wyner showed that the physical layer (PHY) security could be an alternative solution to mitigate the information leakage. Friendly jammers and/or legitimate terminals send artificial noise/interference to confuse the illegitimate terminals. There are several other Abbreviations: LRA, leakage rate analysis; NOMA, nonorthogonal multiple access; CC, cooperative communications Int J Commun Syst. 2020;33:e4387.wileyonlinelibrary.com/journal/dac