Improving Reliability of Hybrid Bit-Semantic Communications for Cellular Networks

TL;DR

This paper enhances the reliability of hybrid bit-semantic communication networks in cellular systems by deriving analytical outage probabilities, proposing a semantic utilization metric, and optimizing cell radius for specific user requirements.

Contribution

It introduces closed-form expressions for outage probability and cell radius optimization in hybrid SemCom and BitCom networks, addressing practical deployment challenges.

Findings

Derived analytical outage probability expressions.

Proposed a semantic utilization metric.

Validated results through simulations.

Abstract

Semantic communications (SemComs) have been considered as a promising solution to reduce the amount of transmitted information, thus paving the way for more energy-and spectrum-efficient wireless networks. Nevertheless, SemComs rely heavily on the utilization of deep neural networks (DNNs) at the transceivers, which limit the accuracy between the original and reconstructed data and are challenging to implement in practice due to increased architecture complexity. Thus, hybrid cellular networks that utilize both conventional bit communications (BitComs) and SemComs have been introduced to bridge the gap between required and existing infrastructure. To facilitate such networks, in this work, we investigate reliability by deriving closed-form expressions for the outage probability of the network. Additionally, we propose a generalized outage probability through which the cell radius that achieves a desired outage threshold for a specific range of users is calculated in closed form. Additionally, to consider the practical limitations caused by the specialized dedicated hardware and the increased memory and computational resources that are required to support SemCom, a semantic utilization metric is proposed. Based on this metric, we express the probability that a specific number of users select SemCom transmission and calculate the optimal cell radius for that number in closed form. Simulation results validate the derived analytical expressions and the characterized design properties of the cell radius found through the proposed metrics, providing useful insights.