Unsourced Random Access Using ODMA and Polar Codes

We utilize the on-off division multiple access technique in unsourced random access and develop a high-performing solution operating on both Gaussian and fading multiple access channels based on polar coding. We propose a transmission structure where a fixed part of the transmission frame is utilized for pilot transmission while the users exploit a randomly-selected small fraction of the rest of the frame for data transmission. Our proposed scheme employs a simple, yet efficient pattern detection and single-user decoding algorithm at the receiver, which leads to a superior performance with similar complexity, or a competitive performance with a significantly lower complexity compared to the existing approaches.