An ODMA-Based Unsourced Random Access Scheme with a Multiple Antenna Receiver

TL;DR

This work investigates the unsourced random access scheme assuming that the base station is equipped with multiple antennas, and proposes a high-performing solution utilizing on-off-division multiple access utilizing on-off-division multiple access.

Abstract

We investigate the unsourced random access scheme assuming that the base station is equipped with multiple antennas, and propose a high-performing solution utilizing on-off-division multiple access. We assume that each user spreads its pilot sequence and polar codeword to the pilot and data parts of the transmission frame, respectively, based on a transmission pattern. The iterative receiver operation consists of pilot and pattern detection followed by channel vector and symbol estimation, polar decoding, and successive interference cancellation. Numerical findings demonstrate that the proposed scheme has superior performance compared to the state-of-the-art in various antenna settings.

Figures (6)

• Figure 1: The proposed transmit signal structure of multiple users. The utilized time instances in the pilot and data parts are shown by green and red boxes, respectively.
• Figure 2: Encoding process for a user in the proposed scheme.
• Figure 3: Decoding process of the proposed scheme.
• Figure 4: Comparison of the required $E_b/N_0$ versus the number of active users for $M = 50$ and $P_e \leq 0.05.$
• Figure 5: Comparison of the required $E_b/N_0$ versus the number of active users for $M = 8$ and $P_e \leq 0.1.$