The demand for marine wireless/wired integrated technology and Voice over Internet Protocol (VoIP) products has rapidly increased with the transition of the marine satellite communication market from Inmarsat to MVSAT, the signing of international agreements, and enhanced social awareness. As shown in Figure 1, the marine satellite communication market is mostly composed of foreign companies, while domestic companies are limited to agents, AS, and installation support. Although 75% of offshore plants undergo drying in Korea, domestic companies including MRC, Net, and Han-shin Electronics account for only 30% of the marine plant network equipment market. Given that the key products are analog equipment, domestic companies are facing a decrease in their market shares. This reinforces the importance of acquiring IP-based network equipment technology.

Figure 1: 
Marine communication equipment markets

With the diversification and sophistication of communication equipment in offshore plants, new communication devices often have integrated functions to reduce costs and facilitate maintenance. Given the recent advances in communications and the increased proportion of IT equipment on ships, it is necessary to utilize products that offer integrated network management and remote maintenance.

The All-In System by Omega Integration and the Marine System by L-3 M&PS can not only fulfill user requirements according to the sizes and purposes of the ships and offshore plants, but can also provide solutions for easier management. As shown in Figure 2, the two systems represent 60% of the entire market.

While Omega Integration and L-3 M&PS are more focused on network equipment, Kongsberg, a leading company in marine automation, supports the efficient maintenance of offshore plants and ships by managing types of various onboard equipment through a bridge system known as K-INMS (Kongsberg Information Management System). JRC, a leading company in marine communications, developed a remote maintenance system (RMS) to offer remote maintenance for their products. This is shown in Figure 3.

Figure 2: 
Market share of marine satellite communication

Figure 3: 
JRC Remote Maintenances System(RMS)

The offshore plant industry has shown a heightened interest in safety equipment following the recent oil spill in the Gulf of Mexico. Major brands have enforced related regulations, and latecomers are facing higher market barriers [6].

Basic regulations for offshore plants are shown in Table 1. IEC 61508 is the international standard for the functional safety of electrical and electronic elements [7]. Norsok standards related to telecom systems in offshore plants can be found in Table 2[8]-[10].

Because offshore plants pose various risks to workers, all equipment must be highly reliable and able to recover rapidly from failure, as stated in Section 2.2. In particular, fixed offshore plants must support remote maintenance, as they have very limited access to land. As noted in Section 2.1, analog communication systems are being transformed into IP-based systems, and many problems, such as inexperienced operations and delayed recovery, have resulted from the lack of professionals. User-centered solutions must be developed to allow easier access for crewmen and to minimize losses from human error. Given the trend of integrated telecommunications in offshore plants and the enforcement of international regulations, new systems must comply with the IEEE standard and the Norsok standards.

To address the development of integrated network solutions offering on-site and remote management and the configuration of IP-based network equipment in offshore plants, the following requirements were derived:

• 1. Equipment configuration and system monitoring
• : Supports the configuration and pre-testing of IP-based communications equipment and marine apparatuses; provides monitoring and control for network equipment, CCTV, PAGA, and analog equipment
• 2. Efficient user-centered management support
• : Implementation of user-centered functions to improve accessibility for workers lacking professional knowledge
• 3. Remote management of coastal offshore plants
• : Remote CCTV monitoring via submarine optical cables installed in offshore plants, and remote management of work sites using PAGA
• 4. Integrated system offering the on-site and remote management of offshore plants
• : Alarm warnings for failure using IP-based satellite communication networks (FBB, VSAT, GX, emd); development of remote control system capable of quick recovery
• 5. Fulfillment of IEEE 802, IEEE 802.3, IEEE802.11af, and Norsok T-100 standards

Since there are many analog and digital devices inside offshore plants such as switches, APs, exchangers, PAGAs, CCTVs, and clocks, interface modules that can digitalize analog communication devices and control each device were developed to enable IP-based control. Furthermore, the system was designed to allow for configuration, operation, and fault recovery though a unified processor.

As there are many dangerous areas which are difficult to access in an offshore telecom subsystem, CCTVs, PA, GA were interconnected to support the management of the offshore plant. Furthermore, submarine fiber-optic cables installed on a fixed platform and a high-speed IP maritime satellite network are used to manage the internal work environments of offshore plants from onshore.

It is practically impossible for people who have no background knowledge or experience with networks to operate an L3 switch, which is a basic component of the IP networks inside offshore plants. However, IT and/or network specialists do not exist in offshore plants. Therefore, the system was configured to allow for the easy setup and monitoring of a telecom subsystem using an operation program developed in accordance with the process. Furthermore, the equipment configuration and pre-test features were implemented to support the installation and test operation of the equipment.

The specifications of the system used in this study, as shown in Figure 9, are identical to those of a fixed platform equipped with submarine optical cables and satellite communications. The program development environment, presented in Figure 10, is the MS.NET framework.

Figure 9: 
INMS development environment

Figure 10: 
Main screen of INMS program

The main screen of the INMS was designed as shown in Figure 8 to enable the configuration of IP-based network equipment, status monitoring, equipment operation, and remote control of offshore plants.

Given that the equipment configuration and status monitoring are not used constantly, detailed functions become accessible depending on input by the user. Users are able to monitor and control common equipment such as the PAGA, IP-PBX, and CCTV equipment, while also having access to navigation data and alarm messages.

In accordance with ship-owner requirements, offshore plants consist mostly of IP-based network equipment. As presented in Figure 11, the digital conversion of sound sources from an analog public address (PA) system was required for synchronization with INMS, and a PAGA interface module was developed for integrated management with the GA equipment. Performance tests were carried out as shown in Figure 11.

Figure 11: 
PAGA interface module

As presented in Figure 12, the basic framework of the INMS program is the server library on land, the client library of the offshore plant, and a common library. From a technical perspective, its components are the communication service, server gateway application, and client gateway application. In particular, TCP and ZIP compression modules are not used in the INMS framework. It is optimized for a satellite communication environment by integrating a data transmission function with high-efficiency compression.

Figure 12: 
Basic framework of the INMS program

For the on-site and remote operation of INMS in real time, communication between offshore plants and land is essential. Synchronized communication is necessary to synchronize data. As shown in Figures 9 and 10, an auto-connection management function was introduced to enable session connections without a separate connection application, and a connection scheduler was employed to set up satellite session connections according to a schedule. A function test was performed at the KTsat Geumsan Satellite Communications Station as shown in Figure 13.

Figure 13: 
Function test of satellite communication