Cellular Underwater Wireless Optical CDMA Network: Performance Analysis and Implementation Concepts

TLDR

The paper introduces and investigates a cellular underwater wireless optical CDMA network based on optical orthogonal codes. The network employs optical base transceiver stations at hexagonal cell centers, connects them via fiber to an optical network controller, and implements uplink and downlink schemes with an FPGA-based prototype that derives error‑probability expressions. The study presents the network’s structure, principles, and performance across various water types, including derived error‑probability expressions and experimental prototype results.

Abstract

In this paper, we introduce and investigate a cellular underwater wireless optical code division multiple-access (OCDMA) network based on optical orthogonal codes (OOC). The structures, principles, and performance of the underwater wireless OCDMA network in various water types are presented. Since underwater wireless optical links are considered for high-bandwidth underwater communications at short ranges, we will place a set of optical base transceiver stations (OBTS) each in the center of a hexagonal cell to cover a larger underwater area. The OBTSs are connected via fiber optic to an optical network controller (ONC) which operates as the core of the network. An integral expression for system error probability is obtained for both uplink and downlink schemes under a specific channel model expressed in this paper, among many channel models in underwater optical communication systems. Furthermore, an experimental prototype of underwater an OCDMA system including the OBTS, ONC, transmitters, and receivers are implemented using field programmable gate arrays (FPGA).