A Polar Code Based Unsourced Random Access for the Gaussian MAC

Abstract

Massive machine-type communications (mMTC) is one of the key application scenarios for future 5G networks. In the literature, this problem is known as unsourced random access. We propose a polar code based scheme for the unsourced random access Gaussian channel. This scheme is based on T-fold irregular repetition slotted ALOHA (IRSA). We use polar codes as slot codes and investigate their practical performance in T-user MAC. We compare two possible decoding techniques: joint successive cancellation algorithm and joint iterative algorithm. In order to optimize the codes (choose frozen bits), we propose a specialized and efficient design algorithm. Finally, we investigate the performance of the resulting scheme by means of simulations and conclude that replacing of LDPC codes with polar codes in IRSA scheme leads to a significant performance gain.