The Optimal DoF Region for the Two-User Non-Coherent SIMO Multiple-Access Channel

TL;DR

This paper determines the complete optimal degrees-of-freedom region for a two-user non-coherent SIMO multiple-access channel, using novel bounds and a training-based scheme, advancing understanding of multi-user wireless communication limits.

Contribution

It derives the full DoF region for two-user non-coherent SIMO channels, employing new converse bounds and generalizing previous single-user results.

Findings

Complete DoF region characterized for two-user SIMO channels

Achievability demonstrated via a simple training scheme

Converse bounds established using genie-aided and duality methods

Abstract

The optimal degree-of-freedom (DoF) region of the non-coherent multiple-access channels is still unknown in general. In this paper, we make some progress by deriving the entire optimal DoF region in the case of the two-user single-input multiple-output (SIMO) generic block fading channels. The achievability is based on a simple training-based scheme. The novelty of our result lies in the converse using a genie-aided bound and the duality upper bound. As a by-product, our result generalizes previous proofs for the single-user Rayleigh block fading channels.