Browsing by Author "Rajahrajasingh, H"

Now showing 1 - 3 of 3

Embargo
Dual-Channel OOK (D-COOK) Modulation for UAV-Assisted Mixed THz/VLC Systems
(Institute of Electrical and Electronics Engineers Inc., 2025-06) Rajahrajasingh, H; Jayakody, D. N.K; Muthuchidambaranathan P; Tsiftsis, T.A
This paper investigates a dual-hop UAV-assisted communications system that integrates Terahertz (THz) and Visible Light Communication (VLC) over a decode-and-forward (DF) relay that bridges the THz and VLC segments. The VLC channel is modelled to account for additive background noise and deterministic fading, while the THz link is subject to path loss, absorption loss, and pointing errors. A comparative analysis with Free Space Optics (FSO)-VLC and Radio Frequency (RF)-VLC systems highlights the superior performance of the THz-VLC system, especially at high signal-to-noise ratios (SNR), in terms of BER and outage probability. Furthermore, a novel modulation technique is proposed that enables increased data rates. Performance evaluation of the proposed modulation scheme further validates the effectiveness of the system.
Embargo
Dual-Hop Hybrid Communication for Underwater and Terrestrial Systems: A Study on VLC and RF/FSO/THz Integration
(Institute of Electrical and Electronics Engineers Inc., 2025) Rajahrajasingh, H; Jayakody, D.N.K; Tsiftsis, T.A
This paper presents an analysis of dual-hop hybrid communication systems that integrate Visible Light Communication (VLC) for underwater transmission with three different terrestrial communication technologies. Specifically, we compare the performance of VLC with radio frequency (RF), free space optics (FSO), and terahertz (THz) communication in a cooperative framework involving a floating buoy as a relay node. Our results demonstrate that the THz-VLC combination significantly outperforms both the RF-VLC and FSO-VLC configurations in terms of Outage Probability (OP) and overall system efficiency. This work provides valuable insights into optimizing communication pathways in hybrid underwater-terrestrial environments, highlighting the potential of THz technology for enhanced data transmission.
Embargo
Joint Resource Allocation and Network Slicing in Hybrid RF/VLC Systems: A Proportional-Fairness Approach
(Institute of Electrical and Electronics Engineers Inc., 2026-08-01) Rajahrajasingh, H; Jayakody, D. N. K.; Peha, J. M
This article presents a joint resource allocation and network slicing framework for hybrid radio frequency (RF) and visible light communication (VLC) systems based on a proportional-fairness (PF) objective. The proposed approach formulates a convex optimization problem that jointly allocates bandwidth resources across multiple slices and access technologies to balance aggregate throughput and user fairness. A relaxed PF solution is first derived via projected gradient optimization, followed by two practical rounding strategies: a simple threshold-based method and a greedy assignment heuristic that produce integer allocations with low complexity. Simulation results for a 20 MHz hybrid RF/VLC system (10 MHz/band) demonstrate that the proposed PF-based allocation achieves aggregate sum-rates of approximately 450-500 Mb/s with Jain's fairness indices greater than 0.9, thus outperforming static and rounding baselines by 10%-15% in throughput while maintaining high fairness. The analysis is further extended to asymmetric RF/VLC bandwidth conditions, demonstrating that the proposed PF-based slicing maintains high fairness while scaling throughput effectively. These results confirm that the PF formulation effectively captures the throughput fairness tradeoff and provides near-optimal slicing performance under realistic indoor bandwidth and power constraints.