LoFi User Scheduling for Multiuser MIMO Wireless Systems

TL;DR

System simulations demonstrate that the proposed LoFi schedulers outperform a range of state-of-the-art user scheduling algorithms in terms of bit error-rate and/or computational complexity.

Abstract

We propose new low-fidelity (LoFi) user equipment (UE) scheduling algorithms for multiuser multiple-input multiple-output (MIMO) wireless communication systems. The proposed methods rely on an efficient guess-and-check procedure that, given an objective function, performs paired comparisons between random subsets of UEs that should be scheduled in certain time slots. The proposed LoFi scheduling methods are computationally efficient, highly parallelizable, and gradient-free, which enables the use of almost arbitrary, non-differentiable objective functions. System simulations in a millimeter-wave (mmWave) multiuser MIMO scenario demonstrate that the proposed LoFi schedulers outperform a range of state-of-the-art user scheduling algorithms in terms of bit error-rate and/or computational complexity.

Figures (5)

• Figure 1: Example of a set $\mathcal{U}\xspace$ of UEs that is scheduled into two disjoint groups $\mathcal{U}\xspace_1$ and $\mathcal{U}\xspace_2$.
• Figure 2: LoFi++ tests whether swapping the worst UE of each group is beneficial and swaps those UEs if so. Darker UE shades indicate lower post-equalization SINR.
• Figure 3: BER of the proposed LoFi++ method compared to state-of-the-art baselines. LoFi++ outperforms most of the baselines, except the "opt.-based" and exhaustive search, both of which require significantly higher computational complexity.
• Figure 4: Comparison between LoFi and LoFi++. Increasing the number of random restarts $K$ improves the BER.
• Figure 5: Complexity versus SNR performance at 1% BER for the proposed LoFi and LoFi++ UE scheduling methods.