Square vs. Hexagonal OWC Performance

Abstract

Accurate performance evaluation is essential for unlocking the full potential of optical wireless communication (OWC) systems, particularly under different network deployment strategies. This paper presents a comprehensive analytical framework for evaluating OWC system performance that explicitly accounts for key parameters, including inter-node distance, height difference, and full cell geometry, thereby overcoming limitations introduced by simplifying assumptions commonly adopted in the literature. Using the proposed framework, a systematic and balanced comparison between the two most widely used network configurations, namely hexagonal and square deployments, is conducted. Two deployment scenarios are considered. In the first scenario, both deployments employ the same inter-node distance. In the second scenario, the inter-node distance in the square deployment is reduced to account for differences in node density and to enable a fair comparison. Simulation results validate the accuracy of the proposed analytical model and demonstrate that disc-shaped cell approximations can lead to misleading performance predictions. The results further show that, when identical inter-node distances are used, the square deployment generally achieves higher coverage probability across most signal-to-interference-plus-noise ratio (SINR) thresholds. When node density is equalised, the hexagonal deployment provides comparable performance at low and medium SINR thresholds for larger inter-node distances, while the square deployment consistently achieves higher coverage probability at high SINR thresholds. These findings provide practical insights into the impact of network geometry on OWC system design.