Hybrid NOMA Assisted Heterogeneous Semantic and Bit Users Communication

TL;DR

This paper proposes a hybrid NOMA framework that combines NOMA and OMA to improve spectral efficiency by supporting heterogeneous semantic and bit users with optimized power allocation.

Contribution

It introduces a novel hybrid NOMA scheme with a power allocation optimization for maximizing semantic spectral efficiency in heterogeneous user scenarios.

Findings

Hybrid NOMA outperforms OMA in spectral efficiency for heterogeneous users.

The proposed algorithm effectively allocates power between semantic and bit users.

Simulation results demonstrate the benefits of the hybrid approach over traditional OMA.

Abstract

In this paper, we utilize a downlink hybrid Non-Orthogonal Multiple Access (NOMA) framework to support multiple semantic and bit users within the communication network. The hybrid NOMA setup exploits both NOMA and Orthogonal Multiple Access (OMA) which has the benefit of enhancing Spectral Efficiency (SE) by allowing users to dynamically access the resources in multiple heterogeneous slots. This enables integrating semantic and bit users based on their channel gains, while adopting bit-to-semantic decoding order in slots including heterogeneous users. An optimization problem for the power allocation is formulated with the aim of maximizing the equivalent ergodic semantic SE with a constraint on the total available power of the Access Point (AP). The proposed algorithm uses NOMA in shared slots and OMA in bit-user-only slots. Simulation results validate the benefits of heterogeneous users hybrid NOMA setup in comparison to OMA-only for heterogeneous users.