Performance Analysis of a Graphene-Enabled FSO Network Fronthaul Using Spread Spectrum Codes for Beyond 6G Mobile Systems

Abstract

Future wireless infrastructures will demand highly flexible fronthaul solutions able to support dense small-cell deployments on short notice while keeping energy consumption low. This work introduces and analytically examines an optical fronthaul architecture that brings together free-space optical (FSO) transmission, graphene electro-optic modulation, and optical spread-spectrum coding for beyond-6G mobile systems. In the proposed centralized scheme, an energy-efficient graphene microring modulator is followed by optical code-division multiple-access (OCDMA) encoding before the signal is launched over FSO links toward distributed remote units. The graphene coverage of the resonator is tuned so as to minimize the energy spent per transmitted bit without sacrificing high-speed operation. Bit-error-rate (BER) analysis indicates that the network sustains up to 32 remote units when forward error correction is employed, while the optimized modulator draws as little as 4.6 fJ per bit at 42.6 GHz. Taken together, these findings make the proposed approach a compelling option for fast network densification, on-demand broadband provisioning, and emerging AI-oriented mobile infrastructures.