Unsourced Random Access Over Frequency-Selective Channels

We propose and study unsourced random access over frequency-selective channels via orthogonal frequency division multiplexing, employed to mitigate the channel effects. The decoder utilizes a compressed sensing-based joint activity detection and channel estimation algorithm coupled with an algorithm treating interference as noise and successive interference cancellation. Our results demonstrate that the proposed method offers a competitive performance with grant-based frequency division multiple access; and that, the performance loss with estimated channel state information is less than 2 dB when the number of active users is not very large.