# Rate-Splitting Unifying SDMA, OMA, NOMA, and Multicasting in MISO Broadcast Channel: A Simple Two-User Rate Analysis

## TL;DR

This paper demonstrates that rate-splitting with SIC in a two-user MISO broadcast channel unifies and generalizes SDMA, OMA, NOMA, and multicasting, providing a flexible framework that adapts to channel conditions.

## Contribution

It introduces a simple rate-splitting approach that encompasses multiple transmission strategies, showing how it outperforms and unifies existing methods based on channel disparity and directions.

## Key findings

- RS unifies SDMA, OMA, NOMA, and multicasting.
- RS outperforms traditional strategies under certain channel conditions.
- Analytical characterization of sum-rate performance.

## Abstract

Considering a two-user multi-antenna Broadcast Channel, this paper shows that linearly precoded Rate-Splitting (RS) with Successive Interference Cancellation (SIC) receivers is a flexible framework for non-orthogonal transmission that generalizes, and subsumes as special cases, four seemingly different strategies, namely Space Division Multiple Access (SDMA) based on linear precoding, Orthogonal Multiple Access (OMA), Non- Orthogonal Multiple Access (NOMA) based on linearly precoded superposition coding with SIC, and physical-layer multicasting. The paper studies the sum-rate and shows analytically how RS unifies, outperforms, and specializes to SDMA, OMA, NOMA, and multicasting as a function of the disparity of the channel strengths and the angle between the user channel directions.