MRT-based Joint Unicast and Multigroup Multicast Transmission in Massive MIMO Systems

TL;DR

This paper analyzes joint unicast and multigroup multicast transmission in massive MIMO systems, deriving the Pareto boundary of the multiobjective optimization problem to optimize spectral efficiency for both types of transmissions.

Contribution

It formulates a multiobjective optimization problem for joint unicast and multicast transmission, derives its Pareto boundary analytically, and proves the convexity of the Pareto region.

Findings

Pareto boundary of the MOOP is derived analytically.

The Pareto region is convex, enabling simultaneous service of unicast and multicast UTs.

System parameters can be tuned to achieve any Pareto optimal point.

Abstract

We study joint unicast and multigroup multicast transmission in single-cell massive multiple-input-multiple-output (MIMO) systems, under maximum ratio transmission. For the unicast transmission, the objective is to maximize the weighted sum spectral efficiency (SE) of the unicast user terminals (UTs) and for the multicast transmission the objective is to maximize the minimum SE of the multicast UTs. These two problems are coupled to each other in a conflicting manner, due to their shared power resource and interference. To address this, we formulate a multiobjective optimization problem (MOOP). We derive the Pareto boundary of the MOOP analytically and determine the values of the system parameters to achieve any desired Pareto optimal point. Moreover, we prove that the Pareto region is convex, hence the system should serve the unicast and multicast UTs at the same time-frequency resource.