Short packets over fading channels: pilot-assisted or noncoherent transmission?

Giuseppe Durisi (Chalmers University)

Abstract:
In most real-world wireless communication systems operating over fading channels, pilot symbols are multiplexed with the data symbols to facilitate channel estimation at the receiver. How optimal is this strategy when packets are short? Shall one instead avoid learning the channel explicitly, and use instead noncoherent transmission schemes? By using finite-blocklength achievability bounds, I will partly shed light on these questions. Specifically, focusing on application scenarios of relevance for machine-type communications, I will provide evidence that noncoherent schemes are superior in terms of spectral efficiency to pilot-assisted schemes.