Finite blocklength approach for the two-user MISO multiple-access channel with noisy feedback and its performance analysis

Abstract

Finite blocklength (FBL) coding is an important way to realize ultra-reliable and low latency communication (URLLC), which is one of the key requirements in future wireless communication systems. In this paper, a FBL approach is proposed for the two-user multi-input single-output (MISO) multiple-access channel (MAC) with noisy feedback channel for the first time, which generalizes the classical Schalkwijk–Kailath (SK) schemes for additive white Gaussian noise (AWGN) channels. In the proposed scheme, by using minimum mean square error estimate and modulo lattice function, the variance of the receiver’s estimation error converges after several iterations, and for a desired demodulation error probability, the required codeword length is significantly short. We further explore security and robustness performances of the proposed scheme, and the numerical examples show that the proposed scheme almost meets the physical layer security requirement in some cases, and when the receiver’s power is sufficiently large, the sum-rate almost approaches the sum-rate capacity.