Semi-Random Coding With Quantum Amplitude Amplification for Secure Access Authentication in Future 5G Communications

Security has become a critical aspect of 5G ultra-low-latency communications (URLLC) due to the openness and vulnerabilities of wireless system information. By tampering/jamming pilots or reference signals in initial access, denial of service (DoS) attacks can disturb uplink access authentication and paralyse the normal data processing in URLLC. We in this paper propose a semi-random coding strategy inspired by amplitude amplification in quantum domain to encode and decode pilot information on multidimensional resources, such that the uncertainty of attacks can be eliminated. In particular, each of pilot signals is encoded as a unique non-random cover-free codeword but randomly transmitted across N subcarriers without assuming any prior distribution while pilot decoding is done to identify each pilot by the receiver who though only observes the superposition of these codewords. We find that the key of pilot decoding lies in how to identify and eliminate the codeword from attacker. It can be proved that the identification process is always equivalent to finding a unique solution to black-box model with N distinguishable binary inputs. By implementing quantum algorithm on this model, we can quickly determine the result and also precisely portray the characteristics of computing performance in a semi-random environment. A novel expression of failure probability of this URLLC system with short packet transmission is also derived to characterize the reliability performance. Numerical results show how our proposed scheme can maintain high reliability and low latency under pilot-aware attack even without knowing the prior distribution for the attack.