Unsourced Random Access Pilot-Assisted Polar Code Construction for MIMO Channel

Abstract

Massive machine-type communications became the new communication paradigm of the future wireless networks, connecting millions of devices per one base station. Here, with the large number of sensors, device identification becomes infeasible, and existing grant-based transmission protocols should be replaced with grant-free ones or random access protocols. As a result, in this approach the same codebook should be used for all active users, which results in the unsourced random access (URA) paradigm, suitable for many Internet of Things (IoT) scenarios. This paper investigates URA problem over Rayleigh block-fading channels with multiple antenna receivers. We compare several Rayleigh fading channel MIMO approaches. A pilot-based treat interference as noise with successive interference cancellation (TIN-SIC) technique that works well in a MIMO environment with unknown channel coefficients is mainly considered. T− fold ALOHA scheme is used as random access technique. We compare our investigation with a coded compressed sensing (CCS) scheme. We describe our findings with the help of minimum energy per bit (E <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</inf> /N <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> ) necessary to reach the desired per-user probability of error(PUPE).