Multi-User Frequency Assignment for Ultra-Reliable mmWave Two-Ray Channels

TL;DR

This paper proposes a frequency assignment method for multi-user mmWave channels that maximizes minimum receive power, using a generalized knapsack problem approach to improve reliability in two-ray ground reflection scenarios.

Contribution

It introduces a novel frequency assignment algorithm based on a generalized quadratic multiple knapsack problem for ultra-reliable mmWave communications.

Findings

Achieves around 6 dB gain over random assignment in simulations.

Ensures ultra-reliability with limited transmitter knowledge.

Provides a new optimization framework for multi-user frequency assignment.

Abstract

We consider a multi-user two-ray ground reflection scenario with unknown distances between transmitter and receivers. By using two frequencies per user in parallel, we can mitigate possible destructive interference and ensure ultra-reliability with only very limited knowledge at the transmitter. In this work, we consider the problem of assigning two frequencies to each receiver in a multi-user communication system such that the average minimum receive power is maximized. In order to solve this problem, we introduce a generalization of the quadratic multiple knapsack problem to include heterogeneous profits and develop an algorithm to solve it. Compared to random frequency assignment, we report a gain of around 6 dB in numerical simulations.