wireless lan system e

Guidelines

on Shipboard Wireless LAN Systems

November 2009

NIPPON KAIJI KYOKAI

Guidelines on Shipboard Wireless LAN System

Copyright ⓒ 2009 All right reserved

No part of this document may be reproduced in any from, or transmitted by any means, or otherwise, without prior written permission from the Society, For NIPPON KAIJI KYOKAI, Administration Center, 4-7 Kioi-cho, Chiyoda-ku, Tokyo 102-8567 Japan.

Introduction

Introduction

Demands for reductions in crew members and greater sophistication of equipment

fitted onboard ship started from the eighties, at which time shipboard LAN systems

began to be proposed for safe operation of ships. At that time, voyage data and

machinery data were collected and integrated, and these data were made usable from

control spaces and accommodation spaces. In recent years, the requirement for

shipboard LAN systems has been growing with the use of network systems between

ship and shore as a result increased use of satellite communications equipment

(IMMARSAT) and temperature monitoring of reefer containers, in addition to the

functions mentioned above. The diffusion of shipboard LAN systems has been

progressing, especially as more sophisticated systemization of operations has become

required in research ships and special purpose/survey ships.

The basis of the shipboard LAN systems mentioned above is the wired LAN.

Diffusion of wireless LAN systems onboard ships lags in comparison with wireless

LAN systems used on shore.

The reasons are as follows:

1. Radio wave propagation characteristics are difficult to predict onboard ship because of the enclosure of all spaces by steel plates.

2. Interaction, interference and other hindrances to wave characteristics observed on shore may also occur onboard ship.

3. Risks associated with eavesdropping and other security concerns exist.

4. Restrictions on the use of radio waves in various countries are not always clear nor consistent.

However, many commercial products such as wireless IP phones, wireless cameras

and wireless personal computers are already available on the market. If

standardization of wireless LAN construction and infrastructure are established,

wiring between equipment will not be necessary, and systems using wireless LAN

terminals can be easily installed and gain widespread use very quickly.

Considering applications to ships, the adoption of wireless LAN systems is likely

to result in reduced man-hours originally required for laying electric wiring for

shipbuilders. For shipowners too, advantages are many in respect of replacement of

equipment, future expandability (scalability), and greater compatibility with varied

applications. As is the case on shore, the intention to make use of the convenience

afforded by wireless LAN systems on ships is gradually gaining ground.

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Introduction

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In the light of this background, systems with high expandability using wireless

LAN have been proposed in recent years.

On the other hand, rules for wireless LAN systems do not exist in IACS nor in the

existing Rules for the Survey and Construction of Steel Ships (hereafter referred to as

“the Rules”) of ClassNK. To respond to the wishes of shipowners and shipbuilders

considering the installation of wireless LAN systems onboard ships, and to establish

basic design and system requirements for classification so that the relevant systems

can be provided more consistently and effectively onboard ships, ClassNK has

prepared these “Guidelines on the Installation of Shipboard Wireless LAN Systems”

as a general guidance for installing wireless LAN systems onboard ships.

The authors would consider themselves honored if these guidelines prove to be a valuable

reference for the provision of wireless LAN systems onboard ships and contribute to concerned

personnel.

Preface

Preface

These guidelines have been prepared as a reference for wireless LAN systems to be fitted onboard ships. A summary of the guidelines is given below. In section 1, the advantages and disadvantages of wireless LAN is explained in comparison to wired LAN systems from a technical viewpoint. In section 2, wireless LAN systems to which the guidelines apply are defined. As ClassNK does not have experience in dealing with ships fitted with shipboard wireless LAN systems, these guidelines are to apply to communications and installations to which class requirements do not apply. When reliability of wireless LAN equipment and systems becomes fully verified in the future, the guidelines will apply to communications and equipment which are designated as important use in the Rules at the next step. The guidelines will be a base for regularization of Classification Rules in that case. In section 3, a brief explanation is given about the main terms appearing in the guidelines. Explanation on other terms of wireless LAN systems are given in the glossary of terms at the end of the guidelines. In section 4, rules and standards are introduced to assist equipment manufacturers and designers at shipyards. It is expected that requirements of a ship’s flag state and those of the country to which the ship calls will not necessarily be the same. Frequency bands, communication systems, antenna power, etc. deemed acceptable for use today are listed in table form. Frequencies and outputs assigned in foreign countries are also given for future use of foreign made products. It is recommended that ships that are likely to call in Japanese ports should comply with Japanese specifications, in principle. This will likely ensure compatibility in foreign ports also. In section 5, requirements for wireless LAN equipment are described. The main points of these requirements are those for EMC and vibration. Attention must be paid to those points when equipment made for shore use is installed onboard ships. In this section, it is also explained that requirements for equipment described in this section comply with the minimum requirements of the Classification Rules even if the requirements are those for equipment of un-important use. In section 6, system configuration and connection issues are explained to help readers gain a better understanding of basic concepts based on the matters mentioned above. In section 7, operation tests to be carried out by shipbuilders during and after the installation of LAN systems and equipment, as well as performance tests required by ClassNK, are described. In section 8, maintenance is described with examples of network management for a system using a control server. In section 9, the Crew Safety Management Support System is introduced as an application example of shipboard wireless LAN systems which was demonstrated at Sea Japan Tokyo 2008 and the Imabari Maritime Fair in 2009.

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Preface

A recent news article reported that a certain ocean-going passenger ship company had expanded their shipboard services by commencing Internet connection service with the shipboard wireless LAN system and mobile telephones onboard ship. In Japan, a system has been developed and marketed, in which a shipboard surveillance robot with an infrared temperature sensor and a CCD camera on a wireless LAN system transmits fire detection data to a wired LAN. A crew member can call his or her family from any location onboard the ship by connecting a wireless IP phone to his or her home via satellite. The Master can also easily find the location of any crew member onboard the ship via this system. These features effectively improve the seamen’s working environment. In utilizing radio communications on wireless LAN systems, reliability of the communications needs to be fully evaluated by applying it firstly to the communications between devices of un-important use. On the basis of this evaluation, step-by-step introduction needs to be considered regarding expanding applications of the communications to devices of important use in the future. In utilizing wireless LAN systems for the communications between devices of important use, as well as redundancies, such as the back-up arrangement of power supplies, should be taken into account depending on the importance of the role of the wireless LAN system. Application range is so wide that further use may be expected when systems for devices of important use are developed. A working group which studies shipboard wireless LAN systems has been set up in IACS. This working group is tasked with the development of unified requirements for a system based on IEEE802.11 with a schedule to make requirements for radio inter-communications between devices after 2010.

The authors acknowledge with thanks the guidance received from various personnel concerning wireless technical standards, technical terms, and wireless LAN model tests.

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Preface

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Table of Contents

1. What is LAN? ...................................................................................................................1 2. Application .......................................................................................................................2 3. Explanation of terms.........................................................................................................3 4. Standards and rules related to wireless LAN systems.........................................................4

4.1 Wireless LAN standards ..............................................................................................4 4.2 Japanese rules (technical standards) ............................................................................4 4.3 Certification system for technical regulations for compliance of radio equipment in Japan................................................................................................................................7 4.4 Using wireless LAN equipment onboard Japanese flag ships ........................................7 4.5 Frequencies and outputs allowed in each country.........................................................7 4.6 Restrictions on the use of radio waves in port...............................................................8 4.7 Using wireless LAN equipment onboard ships of foreign flags......................................8

5. Requirements applicable to wireless LAN..........................................................................9 5.1 Requirements for specifications ...................................................................................9

5.1.1 Frequency .............................................................................................................9 5.1.2 Wireless LAN access points and maximum output of wireless terminals.................9 5.1.3 Security.................................................................................................................9

5.2 Requirements of equipment .........................................................................................9 5.2.1 Electromagnetic compatibility of equipment (display of CE mark) ........................9 5.2.2 Electromagnetic compatibility (EMC) of equipment on the bridge .........................9 5.2.3 Operating voltage..................................................................................................9 5.2.4 Vibration resistance...............................................................................................9 5.2.5 Ambient temperature conditions............................................................................9

5.3 Requirements for installation.......................................................................................9 5.3.1 Locations for installing equipment.........................................................................9 5.3.2 Precautions during installation ............................................................................10 5.3.3 Measures against vibration..................................................................................10 5.3.4 Power source .......................................................................................................10 5.3.5 LAN cable outfitting procedures..........................................................................10

6. Basic system design of wireless LAN................................................................................ 11 6.1 Basic configuration .................................................................................................... 11 6.2 Design of wireless LAN systems .................................................................................13 6.3 Examples of connection of wireless LAN shipboard equipment ..................................14

7. Procedures for onboard testing .......................................................................................15 8. Maintenance ...................................................................................................................16 9. Advantages and application examples of wireless LAN systems .......................................17

9.1 Application examples of wireless LAN systems ...........................................................17 9.2 Examples of using wireless LAN systems....................................................................18

Appendix App. - 1. Glossary of terms ...............................................................................................23

1. What is LAN?

1. What is LAN?

Generally, LAN (Local Area Network) may be of two types: wired LAN constructed from twisted pair cables, coaxial cables, optical fibers, etc., and wireless LAN constructed from wireless connections using radio waves. LAN has developed onshore as a data communication network for sharing and processing data by integrating personal computers and printers in specific areas such as offices, research institutes, factories or universities.

Wireless LAN made its appearance in the early half of the nineties, and communication standards for such systems were standardized globally in the latter half of the nineties. Since cables and wiring are not required up to the terminal equipment in wireless LAN, it was initially used in offices and the like where office layout needed to be changed frequently. After standardization of communication standards, wireless LAN equipment has been installed in public areas such as train stations, airports and hotels, as shown in Fig. 1, and the public Internet environment has developed rapidly, as well.

In this way, wireless LAN has spread rapidly on land in various fields; along with this spread, the prices of peripheral equipment and terminals have dropped dramatically. This has also led to the spread of such systems in ordinary households, too. Naturally, this kind of diffusion on land is likely to happen in the shipping field, too.

Table 1 shows a comparison of the general advantages and disadvantages of wired and wireless LAN systems.

Table 1 Advantages and Disadvantages of Wired and Wireless LAN Systems

Wired LAN Wireless LAN Advantages * Less external interference, stable

communications. * High communication speeds (mainly 1,000

Mbps). * Comparatively safe considering security

aspects.

* No cables required. * Multiple terminals can be connected and easily

increased. * Since wiring is absent, terminals can be moved

easily. * Place need not be selected; information can be

transmitted while on the move. Disadvantages * Wiring is necessary for connecting each

equipment used in the LAN. * The number of units that can be connected

is limited by the number of ports that can be connected.

* Limitations in the places where LAN can be used.

* Sometimes communications are not stable, depending on the environment.

* Communication speed is low compared to wired LAN.

* Greater considerations need to be given to security aspects of wireless LAN.

* Settings specific to wireless connections need to be made.

Fig. 1 Example of installation of public wireless LAN (in the premises of a Tokyo subway station).

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2. Application

2. Application

These guidelines give a general description of standards related to the specifications, design, and installation of wireless LAN systems installed onboard ships. These guidelines are applicable to communications other than those for important services prescribed in the Classification Rules and those between navigational equipment. For this reason, unless specifically indicated otherwise, classification requirements do not apply to requirements described in these guidelines.

These guidelines do not impose any restrictions on the selection of hardware, materials, or processes for specific items.

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3. Explanation of terms

3. Explanation of terms

The meanings of the terms used in these guidelines are explained in this section. Details of these terms and other related technical terms are given in the glossary of terms in the Appendix of this document.

3.1 Access point

A radio switching device connecting the wireless terminal to the network.

3.2 Network switch

A network switching hub. Also called a switching hub.

3.3 Wireless terminal

The collective name for wireless personal computer, wireless IP phone, wireless camera, etc.

3.4 Control server

A server with functions for maintaining and controlling wireless LAN and wireless terminals.

3.5 LAN cable

Cable for wiring used in the network.

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4. Standards and rules related to wireless LAN


4.1 Wireless LAN standards

The wireless LAN being used at present follow various standards that have been established and for the most part standardized by the IEEE802 Committee. The IEEE802 Committee was set up in February 1980 by the Institute of Electrical and Electronic Engineers (IEEE) with the aim of standardizing LANMAN (Metropolitan Area Networks). The group that discusses wireless LAN in the IEEE802 Committee is referred to as 802.11. The important wireless LAN standards established by IEEE802.11 are shown in the table below.

Table 4.1 Wireless LAN Standards

Standard Established in Frequency band Rated speed Remarks (for Japan

only) IEEE 802.11 1997 2.4 to 2.5 GHz 2 Mbps License not required IEEE 802.11b

October 1999 2.4 to 2.5 GHz 11 Mbps License not required

IEEE 802.11a October 1999 5.15 to 5.35 GHz 5.47 to 5.725 GHz

54 Mbps

5.15 to 5.35 GHz: License not required if used indoors 5.47 to 5.725 GHz; License not required regardless of whether indoors or outdoors

IEEE 802.11g June 2003 2.4 to 2.5 GHz 54 Mbps License not required IEEE 802.11n September 2009 2.4 GHz /5 GHz 300 Mbps

4.2 Japanese rules (technical standards)

Wireless LAN standards are established by IEEE802.11, and each country establishes its own rules based on these standards.

The main technical standards related to IEEE802.11 (2.4 GHz band and 5.2 GHz band) in Japan are as shown in Table 4.2.

For details of the technical standards, refer to the Japanese “Ordinance Regulating Radio Equipment,”* Article 49.20 (radio equipment for use in radio stations of a low-power data communication system).

* For the ordinance, please refer to the following URL on the Internet: http://www.tele.soumu.go.jp/resource/e/equ/tech/orre.pdf

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http://ja.wikipedia.org/wiki/#IEEE_802.11

http://ja.wikipedia.org/wiki/#IEEE_802.11a

http://ja.wikipedia.org/wiki/#IEEE_802.11g

http://ja.wikipedia.org/wiki/#IEEE_802.11n

Table 4.2 List of Main Technical Regulations of Low Power Data Communications Systems (as of October 2009)

Item Technical standard

Frequency 2400 to 2483.5 MHz

2471 to 2497 MHz 5150 to 5250 MHz 5250 to 5350 MHz 5470 to 5725 MHz

Band W52 W53 W56

36, 40, 44, 48 (20 MHz system) 5180, 5200, 5220, 5240 MHz

52, 56, 60, 64 (20 MHz system) 5260,5280,5300,5320 MHz

100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140 (20 MHz system) 5500, 5520, 5540, 5560, 5580, 5600, 5620, 5640, 5660, 5680, 5700 MHz Channel

1,2,3,4,5,6,7, 8,9,10,11,12,13 One channel is regulated from 2412 MHz at 5-MHz interval for center frequencies

14 Center frequency 2484 MHz

38，46 (40MHz system) 5190, 5230 MHz

54，62 (40MHz system) 5270, 5310 MHz

102, 110, 118, 126, 134 (40MHz system) 5510、5550、5590、5630、5670 MHz

Communication method

One-way communication, simplex operation, half-duplex operation or duplex operation

One-way communication, simplex operation system, half-duplex operation or duplex operation using spectrum spread system

One-way communication, simplex operation system, half-duplex operation or duplex operation

One-way communication, simplex operation system, half-duplex operation or duplex operation

One-way communication, simplex operation system, half-duplex operation

Modulation method

(1) Orthogonal frequency division multiplex (OFDM)

method *1, or spectrum

spread method *2

(2) Digital modulation other than (1) above

Direct spread (DS) method, frequency hopping (FH) method or DS+FH method

(1) DS method, OFDM method (2) Amplitude modulation method, phase modulation method, frequency modulation method, pulse modulation method, and their combinations

(1) DS method, OFDM method (2) Other methods

(1) DS method, OFDM method (2) Other methods

Frequency Tolerance ±50×10-6 ±50×10-6 ±20×10-6 ±20×10-6 ±20×10-6

Permissible Values for Occupied Bandwidth

83.5 MHz*3 26 MHz or less *4

38 MHz(OFDM 40 MHz system)

26 MHz or less 19 MHz (OFDM), 18MHz (Others) 38 MHz（OFDM 40 MHz system）

Same as W52 19.7MHz (20 MHz system) 38 MHz（40 MHz system）

Antenna power

10mW/MHz or less, OFDM method in the 40 MHz system is 5mW/MHz or less, However, FH, FH+DS, FH+OFDM methods that use frequencies from 2,427 MHz to 2470.75 MHz are 3mW/MHz or less; methods other than OFDM method or spectrum spread method are 10mW or less

10mW/MHz or less

DS method and OFDM method in the 20 MHz method are 10mW/MHz or less, other methods are 10mW. OFDM method in the 40 MHz system is 5mW/MHz or less

DS method and OFDM method 10mW/MHz or less, other methods are 10mW or less

20 MHz system: DS method and OFDM method are 10 mW/MHz or less, other methods are 10mW or less 40 MHz system: OFDM method is 5mW/MHz or less

Tolerance for antenna power

＋20％、－80％＋20％、－80％＋20％、－80％＋20％、－80％＋50％、－50％

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4. Standards and rules related to wireless L

AN

*5：”A” is calculated in the form of “EIRP divided by 12.14dBi”. If the A is lower than 1, it can be regarded as 1. (Half-value angle θ: angle of the main radiation beam of the horizontal plane and vertical plane of the transmitting antenna.)

*7：The sum of the frequency retention times at arbitrary frequencies within the period obtained by multiplying the diffusivity by 0.4 seconds is 0.4 seconds or less.

Gain of transmitting antenna

12.14 dBi or less However, half-value angle θ is to be 360/A or less (Max. value of A is 10)*5

2.14 dBi or less No regulation No regulation No regulation

Equivalent isotropic radiated power (EIRP)

No regulation No regulation 10mW/MHz or less (20 MHz system) 5mW/MHz or less(40 MHz system)

When 3 dB power reduction function provided10mW/MHz or less (20 MHz system) 5mW/MHz or less(40 MHz system) When power reduction function not available5mW/MHz or less (20 MHz system) 2.5mW/MHz or less (40 MHz system)

When 3 dB power reduction function provided 50mW/MHz or less (20 MHz system) 25mW/MHz or less (40 MHz system) When power reduction function not available 25mW/MHz or less (20 MHz system) 12.5mW/MHz or less (40 MHz system)

Diffusion bandwidth Diffusion rate, Frequency retention time

500 kHz ≤ 5 ≤ ≤400 ms

500 kHz ≤ 10 ≤

≤400 ms No regulation No regulation No regulation

Radar wave detection (DFS)

― ― No Yes Yes

Location where used

Indoors and outdoors Indoors and outdoors Indoors only Indoors only Indoors and outdoors

*6：Value obtained by dividing the diffusion bandwidth by the frequency equivalent to the transmission speed of the modulation signal.

*2：Direct spread (DS) method, frequency hopping (FH) method or DS+FH method or OFDM+FH method.

*1：The number of carriers per bandwidth of 1 MHz should be 1or more.

*3：FH method, DS+FH method or OFDM+FH method.

*4：System other than the *3 above.

4. Standards and rules related to wireless L

AN

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4.3 Certification system for technical regulations for compliance of radio equipment in Japan *

The certification system for technical regulations based on the Radio Law of Japan is established from the four methods (1) to (4) below.

(1) Technical Regulations Conformity Certification (Article 38.6 of the Radio Law)

(2) Construction Design Attestation (Article 38.24 of the Radio Law)

(3) Self-check of compliance to technical regulations (Article 38.33 of the Radio Law)

(4) Certification related to compliance assessment for registration in a foreign country (MRA Law (*) Article 29) (*) Refer to glossary of terms

Equipment that has been certified to conform to technical regulations based on any of the methods (1) to (4) above is affixed with the identification (technical regulation conformity mark) shown in Fig. 4.1.

Fig. 4.1 Example of technical regulation conformity mark. * For details of the certification system, please refer to the following URL on the Internet:

http://www.tele.soumu.go.jp/e/sys/equ/tech/index.htm

4.4 Using wireless LAN equipment on board ships of Japanese flag

Wireless LAN equipment used onboard ships of the Japanese flag are required to comply with the technical regulations of 4.3 above, and the conformity mark is to be affixed on the equipment regardless of whether the products are domestic or foreign made.

4.5 Frequencies and outputs allowed in each country

Table 4.3 shows the status of permitted frequencies and outputs overseas that have been established as of October 2009.

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Table 4.3 Frequencies and Outputs Assigned to Each Country

Wireless LAN standards

IEEE 802. 11b,g

IEEE802. 11b

IEEE 802. 11a

Frequency 2400 to 2483.5

2471 to 2497 5150 to 5250

5250 to 5350

5350 to 5470

5470 to 5725

5725 to 5825

5725 to 5850

5725 to 5875

5825 to 6425

(MHz) Japan 10mW/MHz 10mW/MHz 10mW/MHz 10mW/MHz --- 50mW/MHz --- --- --- --- (EIRP) (EIRP) --- (EIRP) --- --- --- --- US

1W --- --- --- --- --- 1W --- --- ---

(Txout) --- --- --- --- --- (Txout) --- --- --- Canada 1W --- 200Mw

(EIRP) 1W (EIRP)

--- --- --- --- --- ---

(Txout) --- --- --- --- --- --- --- Europe 100mW --- 200mW 200mW --- 1W --- --- --- --- (EIRP) --- (EIRP) (EIRP) --- (EIRP) --- --- --- --- China 500/100 mW --- --- --- --- --- --- 2W

(EIRP) --- ---

(EIRP depending on antenna gain)

--- --- --- --- --- --- 500mW (Txout)

--- ---

Australia 100mW --- --- --- --- --- --- 4W --- --- (EIRP) --- --- --- --- --- --- (EIRP) --- --- India 100mW --- --- --- --- --- --- (Txout) --- --- --- --- --- --- Russia 100mW --- 50mW 250mW 1W 1W 1W 1W --- 1W (Txout) --- (Txout) (Txout) (Txout) (Txout) (Txout) (Txout) --- (Txout)

* Notes ---： Not assigned Empty column: To be assigned but not clear in terms of specific details.

4.6 Restrictions on the use of radio waves in port

Restrictions on frequencies and outputs vary in different countries. Thus careful attention must be paid to the latest conditions of the restrictions in any countries of particular concern. Wireless LAN equipment should not be used in a port where its use is restricted.

4.7 Using wireless LAN equipment onboard ships of foreign flags

In principle, equipment sold in Japan is to be used. However, foreign-made equipment that is not sold in Japan can be used, if the equipment is properly attested in accordance with the Mutual Recognition Agreement Law.

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5. Requirements applicable to wireless LAN


5.1 Requirements for specifications

5.1.1 Frequency Any of the following frequencies is to be used for wireless LAN systems: IEEE802.11b,g（2400

MHz to 2483.5 MHz）, IEEE802.11ｂ（2471 MHz to 2497 MHz）, IEEE802.11ａ（5150 to 5250 MHz）, IEEE802.11ａ（5250 to 5350 MHz）, IEEE802.11ａ（5470 to 5725 MHz）.

5.1.2 Wireless LAN access points and maximum output of wireless terminals

The maximum output is to be 10mW/MHz. However, the maximum output is to be 50 mW/MHz EIRP for IEEE802.11a of 5470~5725 MHz adopting DFS (Dynamic Frequency Selection) and TPC (Transmitter Power Control) technologies.

5.1.3 Security

To avoid unauthorized connection by a third party or eavesdropping of wireless communications, the use of security equivalent to WPA-PSK is recommended. WEP is not recommended since it has been pointed out that it can be decoded within a short period of time.

5.2 Requirements of equipment

5.2.1 Electromagnetic compatibility of equipment (display of CE mark) Since a ship is likely to enter EU waters, in principle, all equipment should be affixed with the CE

mark indicating compliance with the EU Directive on Electromagnetic Compatibility.

5.2.2 Electromagnetic compatibility (EMC) of equipment on the bridge Access points provided on the bridge are, in principle, to have equipment that have cleared the EMC

test prescribed in IEC60945 Ed.4 for preventing interference with navigation instruments provided in the bridge.

5.2.3 Operating voltage

Equipment that works on 100 to 220 volts AC is to be used. The equipment is to remain functional without being cut off even during power supply variation, up to a 6% rise and 10% drop in voltage, occurs. In case of a blackout, the equipment should be capable of having its operation restored immediately after recovery from the blackout.

5.2.4 Vibration resistance

The vibration resistance function of the equipment should be resist to vibration at the location where it is installed.

5.2.5 Ambient temperature conditions

To ensure correct operation of wireless LAN equipment, the requirements set forth in Part H, section 1.1.7 of the Rules are to be adhered to, unless specifically noted otherwise.

5.3 Requirements for installation

5.3.1 Locations for installing equipment Equipment is to be installed at an adequately ventilated location so that it is not exposed to risks

of mechanical damage, nor damaged from water, steam or oil. Moreover, if this equipment is to be installed at locations where explosive air-fuel mixture, or

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combustible gas is likely to accumulate, then it is to be of a type approved as being explosion-proof.

5.3.2 Precautions during installation If lamps indicating continuity and operating status are provided in the equipment, these are to be

fitted so that the status can be checked easily. Equipment provided with fuses and breakers is to be installed so that they can be easily replaced and maintained.

5.3.3 Measures against vibration

The shipbuilder is to determine the most appropriate method for installing the equipment provided at each access point depending on the condition of the vibrations anticipated so that the equipment can withstand the vibrations that occur at the location where the equipment is installed. If necessary, measures should also be adopted including the use of shock absorbing materials or securing methods so that vibrations do not affect the equipment directly.

5.3.4 Power source

Redundancy of power supply is not required, unless specifically noted in the design specifications.

5.3.5 LAN cable outfitting procedure

Laying, supporting, fixing, penetrating bulkheads, and connections of LAN cables are subject to Part H of the Rules.

6. Basic system design of wireless LAN


6.1 Basic configuration

The basic equipment that constitutes a wireless LAN system is described below.

(1) Access point

(2) Network switch

(3) Wireless terminal (wireless personal computer, wireless IP camera, wireless IP telephone, etc.)

(4) Control server

(5) LAN cable

An example of the configuration of a common wireless LAN system provided onboard a ship is shown in Fig. 6.1.

To construct a wireless LAN system, access points are installed at various locations on the ship, and wired with LAN cables using network switches as the pivot points. The control server may be installed in the wheel house, cargo control room, engine control room, or other suitable location.

IEEE802.11a/b/g Wireless Terminals

Control server

LAN Cable

Access Point

Network switch

Fig. 6.1 Example of the configuration of a typical wireless LAN system onboard ship.

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Fig. 6.2 shows an example of access points provided in a typical onboard LAN system.

(1) Example of access point in engine room.

(2) Example of access point in accommodation space.

(3) Example of access point in acc. space corridor.

Fig. 6.2 Example of provision of access points onboard ship.

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If the access point has a repeater function for relaying data between wireless terminals, the system

can be configure as shown in Fig. 6.3.

Fig. 6.3 Example of wireless LAN system with repeater function.

IEEE802.11a/b/g Wireless terminal

Control server

Relay by repeater function

LAN cable

Network switch

Access point

If the repeater function mentioned above is used, for instance, and if two access points are distant from each other as shown in Fig. 6.4, the laying of LAN cables to the access points shown in the figure by dotted lines is no longer required; thereby eliminating cable laying costs.

LAN cable LAN cable need not be laid

Relay by repeater function

Fig. 6.4 Example of use of repeater function.

6.2 Design of wireless LAN

When deciding the subdivisions to which communications are to be made during design of wireless LAN, the arrangement of access points and the selection of frequencies (standard) are to be considered. All the requirements mentioned in Chapter 4 above should also be considered at the same time.


6.3 Examples of connection of wireless LAN shipboard equipment

Construction of a system for transmitting data through a wireless LAN system such as voyage and surveillance data of equipment fitted onboard the ship can be considered.

In this way, when shipboard equipment is connected to wireless LAN, measures need to be taken to ensure that factors that generate noise and improper operation, etc., are not transmitted from the shipboard equipment to the wireless LAN system, regardless of whether they are essential or non-essential services. Consideration also needs to be given to ensuring that any troubles and faults that may occur in the wireless LAN system do not affect other equipment.

Interface equipment may be installed for electrically insulating the space between the navigation equipment or monitoring system and the wireless LAN system, as shown in Fig. 6.5, for instance.

Navigation equipment

Interface equipment

Wireless LAN system

Monitoring

system

Fig. 6.5 Example of interface equipment.

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7. Procedures of on board test

7. Procedures of onboard testing

A functional check of the wireless LAN system is to be carried out under conditions in which it will be normally used after the system has been installed onboard the ship. If the wireless LAN system complies with these guidelines which limit its application to non-vital services, the attendance of a surveyor is not necessary at confirmation tests of operation. However, in cases where wireless LAN equipment that has not cleared the IEC60945 Ed.4 EMC test has been installed on the bridge, it must be confirmed during sea trials that this wireless LAN equipment does not affect navigational equipment and vice-versa. In confirming a wireless LAN system’s operation, the individual confirmation tests should be carried out individually with all installed radio equipment such as wireless IP telephones, wireless PC, wireless cameras, etc. Fig. 7.1 shows examples of the confirmation testing of a wireless LAN system onboard a ship.

(1) Example of voice test by wireless IP telephone.

(2) Example of data communication test of wireless personal computer and wireless camera.

Fig. 7.1 Examples of onboard testing of wireless LAN equipment.

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8. Maintenance

8. Maintenance

The maintenance of a shipboard wireless LAN system is to be carried out in accordance with the instruction manual of the manufacturer for each component of the system. Introduction of a network management system to the control server will make it possible to always monitor the operation of equipment and contribute to maintaining and effectively managing the operational quality of a shipboard wireless LAN system and to realize stable operation of the system. Fig. 8.1 shows an example of the network management system screen which displays the operational status of a connected access point, event log, etc.

Fig. 8.1 Example of network management system screen.

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9. Advantages and Application examples of wireless LAN system

9. Advantages and examples of application of wireless LAN systems

9.1 Application examples of wireless LAN systems

Figure 9.1(2) shows an engine room monitoring system as an example application of a wireless LAN system. In the engine room monitoring system, surveillance cameras are installed around the main engine, generator, incinerator, and boiler to monitor conditions of the engine room from the wheel house and the engine control room. To set up this engine room monitoring system as a wired system, each surveillance camera in the engine room needs to be connected to the control panel by a coaxial cable, as shown in Fig. 9.1(1). On the other hand, to set up the engine room monitoring system as a wireless system, wireless surveillance cameras need not be connected by coaxial cables but with one or more access points by radio waves, as shown in Fig. 9.1(2).

Signal wiring to each surveillance camera is not required in a wireless LAN system. This means that, when changing the arrangement of surveillance cameras or installing an additional camera onboard a ship in service, only power-supply wiring is required. Additional power may be supplied from the nearest lighting power distribution board, and changes in the layout can be made with minimum outfitting work.

Fig. 9.1(1) Example of configuration of a wired engine room monitoring system.

Fig. 9.1.(2) Example of configuration of a wireless LAN engine room monitoring system.

Control Panel

Monitor

Coaxial cable

Surveillance camera

Control panel

LAN cable

Wireless surveillance camera

Monitor

AC power

Network switch

IEEE802.11a/b/g Access point

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Surveillance cameras may also be used as a security measure against suspicious persons in addition to their use of monitoring the engine room. In installing a surveillance camera to guard against suspicious persons, the cameras are to be installed at the locations specified in the ship’s security standards. Such locations are generally in the vicinity of the boarding gangway and the mooring deck.

Adoption of a wireless LAN based surveillance system as a measure against suspicious persons makes it easy for ships in service to install a surveillance system. Furthermore, it is efficient in terms of additional installation or relocation of surveillance cameras related to the future review of security standards.

When wireless communications between the ship and the port office at the port of call becomes available, the video images on the surveillance camera onboard the ship can be monitored by the port office. This feature can also contribute to the implementation of a highly sophisticated port security system.

9.2 Examples of using wireless LAN system

The concept of the Crew Safety Management System based on the introduction of a shipboard wireless LAN system was announced at the Sea Japan exhibition in 2008, after joint development of the system by MITSUBISHI HEAVY INDUSTRIES, LTD. and FURUNO ELECTRIC CO., LTD., as a system for ships using wireless LAN.

Fig. 9.2 shows an overview of the Crew Safety Management System. The Crew Safety Management System is a system that combines a wireless IP telephone system that enables talking in all areas on the ship when each crew member carries a wireless IP telephone, and a wireless LAN position data system that detects the position of the wireless IP telephones (=crew) by detecting the connection data between the access point and the wireless IP telephone.

Management server

Access point

Network switch

Position detecting screen

LAN cable

Wireless IP phone Crew

Fig. 9.2 Example of Crew Safety Management System.

Similar to the commonly available mobile phone, voice and instant messaging (mail), image sending and receiving functions can be used in the wireless IP phone by introducing the system shown above. Moreover, by integrated control of position data of crewmembers onboard the ship, the work efficiency during normal hours can be enhanced based on the position data, support for emergency response in the event of a fire or accident becomes more effective, and overall safety of

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the ship is enhanced. If the crew position data is recorded and saved on a hard disk or other storage media, the data will also be useful in post-accident analyses.

At the Imabari Maritime Fair (BARI-SHIP) in 2009, the concepts of shipboard safety surveillance data and ship-shore communications were combined with the Crew Safety Management System mentioned above, and an expanded Crew Safety Management System (hereafter referred to as Ship Safety Management Support System) was announced by the same companies, namely MITSUBISHI HEAVY INDUSTRIES, LTD., and FURUNO ELECTRIC CO., LTD. Fig. 9.3 shows an overview of the Ship Safety Management Support System. By superimposing and displaying the data obtained from the fire control panel, which is a shipboard safety surveillance data, and the crew position data, this system can support fire extinguishing activities and escape guidance based on the location of the crew members when a fire occurs. Similarly, by superimposing and displaying crew position data and door surveillance data and surveillance cameras, the location of crew members can be instantaneously known when an abnormality is detected by the surveillance camera when the door is opened or closed. Thus, the system is effective as a security measure against the entry of suspicious persons during service or during cargo operations.

Fig. 9.3 Example of Crew Safety Management Support System.

Ship’s earth station.

Wireless Tag

Satellite

Shore office

Interface

Mgmt server

Crew

Wireless IP phone

Fire control panel Door surv. panel Surv. camera GPS/DGPS Other surveillance

Ship safety surveillance. info

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Furthermore, by connecting the system to satellite communications equipment such as IMMARSAT and VSAT, surveillance camera images and status of fires, locations of crew members, and other shipboard conditions can be easily known even from shore-based management companies. In recent years, wireless tag is being offered as portable wireless terminal. Crew members are likely to carry wireless tags, which has excellent portability or wireless IP telephones with voice functions. The examples above show that operations and security measures which were not possible in the past can be implemented by introducing new features such as crew position data. As a case example of the above, the Safety Centre on Passenger Ships (hereinafter referred to as the “Safety Center”) may be pointed out. Safety Centers will become mandatory onboard passenger ships in accordance with SOLAS Chapter II-2 (effective on 1 July 2010). The Safety Center is installed with the objective of managing emergency situations such as fires, by collecting shipboard safety information from fire detection systems, television surveillance systems, fire doors, and general emergency alarms, etc. The SOLAS Convention also requires a means of communication between the Safety Center, the central control station, the navigation bridge, the engine control room, and fire control station for fire extinguishing systems and fire equipment lockers. By constructing the Ship Safety Management Support System mentioned above, the collection and distribution of information to and from each crew member becomes possible in the locations other than those required by SOLAS. Attachment of wireless tags to passengers and lifejackets on passenger ships can help effectively locate passengers and crew members and assist in the provision of evacuation guidance. The Bridge Navigational Watch Alarm System (hereinafter referred to as “BNWAS”) may be pointed out as another case example showing expandability in the future as one of the advantages of a wireless LAN system. BNWAS was adopted at the MSC86 in May 2009. NOTE) An example of a wired BNWAS is shown in Fig. 9.4(1) and a wireless LAN BNWAS in Fig. 9.4(2). NOTE : Currently, test standards IEC 62616 of BNWAS are under development at the IEC. It is not clear at this moment whether wireless LAN systems will be adopted in the future or not. BNWAS is required to issue an alarm outside the bridge at locations such as the Master’s, back-up officer’s and other crew members’ locations. A control unit is provided in the bridge and buzzers as well as buzzers with switches are provided at alarm locations. For this reason, signal lines must be wired from the control panel in the bridge to the buzzers at each of the alarm locations, as shown in Fig. 9.4(1). BNWAS is mandatory on existing ships. In addition to the cost of equipment, considerable cost will be necessary for wiring work. On the other hand, if wireless LAN BNWAS becomes available, wiring work from the bridge to each of the alarm locations becomes unnecessary by installing access points and alarm units at each of the alarm locations shown as Fig. 9.4(2). Furthermore, in ships where a shipboard wireless LAN system is already provided, only wiring between the control panel and already-installed network switches is required to configure BNWAS. Up to here, the advantages of adopting a wireless LAN system and its application examples have been explained. With a wireless LAN system fitted onboard a ship, the ship can flexibly correspond to expansion in installations such as convenient wireless IP telephones, surveillance cameras for use in security measures, and mandatory installations such as BNWAS required by SOLAS regulations. Owing to the easy expandability of the wireless LAN systems mentioned above, a number of functions and information can be used in a wireless LAN system infrastructure, and various applications and possibilities are expected after the introduction of such systems onboard ship in the future.

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Buzzer with switch

Buzzer

Buzzer with switch

Buzzer Control unit (bridge)

Marine cable

Fig. 9.4(1) Example of BNWAS with wiring.

Control unit (bridge) LAN cable

AC power

Network switch

Alarm unit

AC power

Fig. 9.4(2) Example of BNWAS expansion by wireless LAN.

References

References

(1) International Telecommunication Union “Radio Regulations and its Appendix”, Denki Tsushin Shinkokai, March 1999.

(2) “Radio Law Statutes”, Denki Tsushin Shinkokai, December 2008. (3) "802.11 High speed wireless LAN textbook”, Editors: Hideaki Matsue, Masahiro Morikura;

Published by: Showa Mitsuhashi, Publisher: IDG Japan; IDG Information Communication Series, 29 March 2003.

(4) “Crew Safety Management System by introducing shipboard wireless LAN", MITSUBISHI

HEAVY INDUSTRIES, LTD., FURUNO ELECTRIC CO., LTD., FURUNO SYSTEMS, SEA JAPAN data, April 2008.

(5) The Japan Maritime Daily, “POA that enables mobile phone use”, 5 November 2008. (6) Kaiji Press Co., Ltd.., “Development of the world’s first autonomous surveillance robot for fire

detection”, 3 April 2008. (7) “Ship Safety Management Support System”, MITSUBISHI HEAVY INDUSTRIES, LTD.

FURUNO ELECTRIC CO., LTD., FURUNO SYSTEMS, Imabari Maritime Fair data, May 2009.

(8) “Rules for the Survey and Construction of Steel Ships and NK Guidance, Part H Electrical

Installations”, NIPPON KAIJI KYOKAI, 2009 edition.

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Appendix

Appendix

App. - 1. Glossary of terms

・Bluetooth

A wireless communication technology used to communicate over a distance of a few meters; uses radio waves in the 2.4 GHz band. The maximum transmission speed is 3 Mbps. Small-scale wireless networks can be easily formed; therefore, this technology is used in wireless hands-free mobile phones for connecting wireless headset, wireless headphones for music players, wireless mice for PC and so on.

・IEEE 802.11

IEEE stand for the Institute of Electrical and Electronic Engineers, the world’s largest association of electrical and electronic engineers in the USA. This association has a committee named 802. The working group (WG) 11 under the umbrella of this committee, develop standardization of wireless LAN. IEEE 802.11 is the first wireless LAN standard established by the IEEE. The medium access control (MAC) layer protocol that controls communications and the physical layer protocol that handles data transmission and wireless frequency bands, were mainly established.

・IEEE802.11a

A wireless communication technology used to communicate over a distance of tens of meters; uses radio waves in the 5 GHz band. The maximum transmission speed is 54 Mbps. It is mainly used in notebook computers that can use wireless LAN, and it contributes to improving user-friendliness such as facilitating mobility through wireless network connections. Limitation of usable bands and prohibition in use outdoors are set in some countries to prevent interference with existing radio systems. In Japan, the usable bands are 5.15 - 5.25 GHz (W52), 5.25 - 5.35 GHz (W53) and 5.47 - 5.725 GHz (W56), and only W56 can be used outdoors. In W53 and W56, radio transmission stops and the transmission channel is changed to prevent interference when radio waves from meteorological radar exist. 5 GHz radio waves, due to their higher frequency than 2.4 GHz, have a narrower service area and are in comparison susceptible to interference from obstacles.

・IEEE802.11b

A wireless communication technology used to communicate over a distance of tens of meters; uses radio waves in the 2.4 GHz band. The maximum transmission speed is 11 Mbps. It has a wider coverage area and is less susceptible to obstacles compared with 5 GHz. However, it is susceptible to interference and noise from microwave ovens and medical equipment nearby.

・IEEE802.11g

A wireless communication technology used to communicate over a distance of tens of meters; uses radio waves in the 2.4 GHz band. The maximum transmission speed is 54 Mbps. Mainly installed in notebook computers that use wireless LAN. It is also used in wireless IP phones and wireless surveillance cameras. Since it uses the 2.4 GHz band, it has the same disadvantages as 802.11b.

・IEEE802.11n

Next-generation wireless LAN specifications that increase the transmission speed to above 100 Mbps through a technology that uses multiple radio frequencies simultaneously called Multiple

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Appendix

Input Multiple Output (MIMO). It has upward compatibility with 802.11a/b/g.

・Industry Science Medical Band (ISM band)

Frequency bands specified for the industry, science and medical fields; frequencies are assigned in the 900 MHz band, 2.4 GHz band and 5.7 GHz band.

・Mutual Recognition Agreement (MRA) Law

The abbreviated name of “The Act for Implementation of the Mutual Recognition between Japan and Foreign States in Relation to Results of Conformity Assessment Procedures of Specified Equipment (Law No. 111, 2001)”. Wireless LAN equipment approved by a registered foreign conformity assessment body is treated as equipment conforming to the Technical Regulations Conformity Certification System of the Radio Law.

・OFDM （Orthogonal Frequency Division Multiplex）

Orthogonal Frequency Division Multiplex system. System in which data is divided and spread over multiple waves and transmitted in parallel after multiplexing. Since the phases of two waves are offset by 90 degrees (orthogonal), the waves are not likely to interfere. For this reason, a part of the multiple waves can be densely arranged, enabling the usage efficiency of frequencies to be increased.

・PoE （Power over Ethernet）

Standard and method for supplying power to equipment through twisted pair cable for data transmission. PoE can supply a maximum of 15.4 W of power (maximum 48 V. Maximum current value is 350 mA).The maximum power on the receiving side is taken as 12.95 w considering the power loss in the cable.

・ Spectrum Spread (SS) modulation system

A modulation system by spectrum spread technology. Primarily modulated digital signals are transmitted after being spread to a wide frequency band by secondary modulation with a spread code. Received signals are demodulated by the same spread code to the original signals.

・TCP/IP (Transmission Control Protocol/Internet Protocol)

A standard communication protocol used in the Internet and intranets.

・WEP (Wired Equivalent Privacy)

A method to encrypt wireless transmission data so as to prevent eavesdropping. It was suggested that the code could be decrypted since the encryption strength was low; therefore, it is not recommended as a security measure.

・WPA-PSK (Wi-Fi Protected Access)

A method to encrypt wireless transmission data so as to prevent eavesdropping. By periodically updating the encryption key, the code becomes difficult to be decrypted; thus, the security is stronger than that provided by WEP.

・WPA2-PSK

A method to encrypt wireless transmission data so as to prevent eavesdropping. Security is further enhanced by use of a stronger encryption system than that used in WPA-PSK.

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Appendix

・ Frequency hopping (FH) system

A system of the spectrum spread modulation systems. Rapid changes are made to the transmission frequency by using spread code.

・ Switching hub

In a normal hub, data selection and pickup is by each terminal but in a switching hub, the data sent from the terminal is analyzed, destination is detected and data is sent only to that destination. For this reason, network load is reduced and security is enhanced.

・ Direct spread (DS) system

A system of the spectrum spread modulation systems. The modulated signals are directly multiplied by spread code to spread the transmitted frequency bandwidth.

・ Equivalent isotropic radiated power

Index that expresses the transmitting performance. Energy radiated in a certain direction from the antenna is converted to transmitting power of an “equivalent antenna” (ideal antenna) to express the strength of the wave.

・ Registered Foreign Conformity Assessment Body

Refers to the organization registered as a technical standard assessment organization with which Japan has concluded the Mutual Recognition Agreement related to approval of standards for wireless equipment.

Examples of such organizations are the Dutch TELEFICATION B.V, the German CETECOM ICT Services GmbH, BABTM, Phoenix Testlab GmbH, and EMC Cert Dr. Rasek GmbH, and the British KTL.

・ Network switch

Also called a switching hub. Refer to “switching hub.”

・ Hot spot

Public locations outside homes and offices, such as railway stations and airports, where Internet connection services are available. They contribute to improve convenience in accessibility to E-mail and Web-sites in the field.

・ Wireless IP phone

IP phone or VoIP (Voice over Internet Protocol) phone is a telephone system which uses a transmission technology to transmit voice signals on an IP network after converting the signals into packets with compression and digital coding method. When combined with wireless LAN technology, they are called as Wireless VoIP phones or WVoIP phones.

・ Access point

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Appendix

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A relaying device which connects wireless LAN equipment such as wireless LAN enabled notebook PCs and wireless IP phones to wired LAN, and exchanges data between wireless LAN equipment and wired LAN. Some access points support router functions. A wireless LAN service area is established with an access point as a center. An access point is often abbreviated as AP.

With a PoE compatible access point, electrical power can be supplied through a LAN cable, then power source wiring work to the access point becomes unnecessary.

Address all inquiries related to the content of this document to: NIPPON KAIJI KYOKAI Material and Equipment Dept. 4-7 Kioi-cho, Chiyoda-ku, Tokyo-102-8567 Telephone ： 81-3-5226-2020 FAX ： 81-3-5226-2057 E-mail ： [email protected]

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