Introduction - Asia-Pacific · Web viewCurrently, essential functionalities, such as routing protocol are implemented separately in both Relay-by-Smartphone and UAS networks. It is

APT REPORT

on

THE POSSIBLE RADIO SERVICES AND APPLICATIONS ONBOARD AIRCRAFT AND VESSELS

No. APT/AWG/REP-56 Edition: September 2014

Adopted by

17th Meeting of APT Wireless Group23 - 26, September 2014

Macao, China

(Source: AWG-17/OUT-16)

APT REPORT ON THE POSSIBLE RADIO SERVICES AND APPLICATIONS ONBOARD AIRCRAFT AND VESSELS

Table of Contents1 Introduction....................................................................................................................................42 Background....................................................................................................................................43 Scope of work................................................................................................................................54 The potential radio services and applications on-board aircraft....................................................54.1 Case 1: Millimetre wave broadband wireless communication between airplane and ground....5

4.1.1 Background......................................................................................................................54.1.2 Application needs.............................................................................................................64.1.3 Experiment.......................................................................................................................64.1.4 Results............................................................................................................................104.1.5 Conclusion......................................................................................................................154.1.6 Future challenge.............................................................................................................15

4.2 Case 2: wireless bridge system using small UAS.....................................................................164.2.1 Background....................................................................................................................164.2.2 Wireless Bridge Using Small UAS...............................................................................164.2.3 Measurement results.......................................................................................................184.2.4 Integration of wireless bridge using UAS and Relay-by-Smartphone...........................214.2.5 Delay and Disconnection Tolerant Message Transmission System using UAS (in case of using single Unmanned Aircraft UA).....................................................................................244.2.6 Hand-Over system of multiple ground stations in multiple unmanned aircrafts operation.......................................................................................................................................28

5 The potential radio services and applications on-board vessel....................................................325.1 Case 1: Wireless Broadband Video Transmission Systems......................................................32

5.1.1 Background and Application Requirements..................................................................325.1.2 System Description........................................................................................................335.1.3 Service Provider Cases...................................................................................................345.1.4 Market Trend..................................................................................................................355.1.5 Future challenges............................................................................................................35

5.2 Case 2: Maritime Broadband Multi-hop Relay Communication System.................................365.2.1 Background and Application Requirements..................................................................365.2.2 System Description........................................................................................................365.2.3 Verification test..............................................................................................................385.2.4 Application Services......................................................................................................415.2.5 Market Trend..................................................................................................................415.2.6 Future challenges............................................................................................................41

6 Summary......................................................................................................................................42

APT/AWG/REP-56 Page 2 of 45

6.1 Summary of the potential radio services and applications on-board aircraft............................426.2 Summary of the potential radio services and applications on-board vessel..............................437 References....................................................................................................................................44


1 Introduction

There are increasing demands for the use of radio services from wherever you are located, including

on-board aircraft and vessel. At the AWG-12 meeting held in Xia Men, China, an agreement was

reached in the Task Group Aeronautical and Maritime (TG A&M) to study the possible radio

services and applications on-board aircraft and vessel. The purpose of this report is to identify the

future needs of special communications for social, industrial and economic development which could

be satisfied by services and applications on aircraft and vessel. Several potential cases are discussed

in this report.

2 Background

To promote new wireless applications and to promote a harmonized vision of wireless

communications systems and services in the Asia-Pacific region to meet the emerging digital

convergence era are the two principle objectives of the AWG. TG A&M extends these general goals

to the aeronautical and maritime field and address the related issues.

According to the terms of reference of TG A&M, several issues of the use of mobile phone as well as

the use of other modern wireless technologies onboard the aircraft and vessels should be considered,

including:

Spectrum harmonization issues including preferred frequency bands and associated

technical characteristics;

Associated regulatory and licensing issues, when considered appropriately.

To study and review future wireless communication technologies on aeronautical and

maritime fields.

With the growth of the penetration of radio communications on business, industry and people’s daily

lives, and with the technology improvements that will make it possible for the use of higher and

wider spectrum bands, it is expected that a variety of radio services and applications will be available

for onboard aircraft and vessel in the future. For example, cellphones will be able to connect to a

pico-cell network built onboard aircraft and vessel, and further connect to a land-mobile network

switching center via satellite link or other kinds of link. Aircraft has been shown to establish a

bidirectional IP communication link with the ground environments by millimetre wave

transmissions, which enables mass volume downloading from the Internet. RFID and sensors based

Internet of vessels can dynamically sense and exchange the information between vessels and harbors,

even between vessels and cargos.


To successfully deliver services and applications mentioned above, it depends on the supporting

features of new technologies, possible allocated spectrum resources and harmonized coexistence

with the current spectrum utilization in different Asia-Pacific countries. The factors also include

safety concerns and it need to be implemented in accordance with all relevant national and

international laws, regulations and policies. Furthermore, the service and application providers

should pay more attention to the market trends, to ensure that he can get support from the latest

infrastructures, facilities and devices. Of course, all these factors should work together, and some

specific challenges should be considered also, for example radio propagation conditions, high

mobility and time delay etc., we must consider how to deal with these challenges carefully.

3 Scope of work

The potential radio services and applications onboard aircraft and vessel are discussed in this report.

Several cases with background, application needs, success factors, experiment, future challenges,

market trends, provider information are described in the following part 4 and part 5, some

characteristics of services and applications will be addressed including operating band, geographic

range, primary/secondary feature, protection requirements and so on. For the cases have been tested,

the related experimental configuration and results will be given. The summary and conclusion of the

report and the references are given in the following part 6 and part 7.

4 The potential radio services and applications on-board aircraft

4.1 Case 1: Millimetre wave broadband wireless communication between airplane and ground

4.1.1 Background

Demand has increased for better mobile phone and wireless local area network (LAN) access for

people on-board aircraft. Now, several airlines have started cabin use of cellular phones with a

system involving satellites. Meanwhile, in Japan, a wireless communication system on passenger

airplanes is also being studied. This study, being executed under the Commissioned Business

program of Japan’s Ministry of Internal Affairs and Communications, has led to the design of an

aero broadband system, called the aero hot spot system, using the millimetre wave band. In the

system, airplanes fly over ground tracking antennas arranged at regular intervals. As the aircraft

passes overhead, the antennas hand over service one after another to the aircraft. The National

Institute of Information and Communications Technology (NICT) and Mitsubishi Electric

investigated a broadband communication system for airplanes in which the millimetre wave (MW)

band (40 GHz band) facilitates broadband wireless communications on airplanes and on the ground.


Some evaluations and experiments toward such a realization have been conducted by the Mitsubishi

Research Institute. The millimetre wave band, such as the over-40-GHz band, is not used heavily in

commercial applications and is expected to facilitate the broadband communication system. The

following part refers to the results of the experiments.

4.1.2 Application needs

Application needs were studied by questionnaire survey, for the purpose of arranging demands for

the communication systems for airplanes in which the millimetre wave band (40 GHz band). The

questionnaire was about utilization form of this system, flight condition of airplanes, needs for the

communication capabilities, etc. The possible users of this system were categorized four groups,

which are aerial survey and imagery, aviation-related experimental research, civil aviation services,

and fixed-wing airplane and rotary-wing airplane development. Table 4.1-1 presents the summary of

the questionnaire results.

Table 4.1-1 Summary of the questionnaire results

Data Aerial photograph, SAR, laser measurement data(for measurement and observation for disaster)

Aviation-related experimental data(image, photograph, and movie)Flight experiments data(data recorder)

Data transfer via the Internet for civil aviation services(text data and images)

Live broadcast system for the helicopter

Data capacity A few dozen ~a few hundred GB

A few dozen GB More than a few dozen GB

More than a few dozen GB

Changingaltitude or turning duringdata transfer

Possible Possible Impossible Possible

Aircraft type Cessna-type planeHelicopter

Fixed-wing airplane and rotary-wing airplane

Civil aircraft Helicopter

Flight altitude 200m~6,000m 5km~15km 5km~15km 150m~1,000mCommunication distance

A few hundred m ~ 10km

100km~200km 200km~400km 30km~50km

Data transfer rate

A few hundred Mbps ~ a few Gbps

More than a few hundred Mbps

A few hundred Mbps ~ a few dozen Mbps

A few dozen Mbps

Flight velocity 200km/h~500km/h 240km/h~1.100km/h 450km/h~1,000km/h ~300km/hRadius of turn Cessna-type plane :

more than 4,000mIn case of 200km/h : more than 900m

5km~25km

Flight hours 4h~7.5h 2~5h Domestic: 1~2hInternational: ~12 hours

More than 1 hour

4.1.3 Experiment

(A) Experiment summary

The verification test using aircraft was scheduled in January 2012 on the island of Oahu, Hawaii,

USA, for the purpose of verifying mass volume downloading by bidirectional communication


between aircraft and the ground. A small airplane was used as the airborne station. Table 4.1-2

presents an overview of the airborne verification test, and Figure 4.1-1 illustrates a diagram of the

airborne verification test. One of the key technologies of the system is to track the target terminal

antennas. To track each antenna position, the antenna system needs to consider the characteristics of

the millimetre wave and the geographical dimensions. The ground-based tracking antenna must

continuously track the aircraft with a high degree of accuracy. The on-board antenna must track the

ground-based antenna by considering aircraft attitude and location. With a reflector controlling the

antenna beam in the system, the mechanism provides a cost-effective, power-efficient tracking

antenna. The ground station has a mechanically controlled reflector to direct the antenna beam in a

specific direction by tilting the reflection disk mechanically. Furthermore, a radio wave was

separately transmitted at 44.55 GHz, in addition to the communication signal wave so that the system

could execute the mono-pulse tracking technique by monitoring the reception level of the radio wave

signal. The system uses the frequency division multiplex (FDD) method for communication. The

transmission and reception frequencies are allocated as 46.8 GHz and 44.45 GHz, respectively, for

simultaneous transmission. The data transfer rate is 141.7 Mbit/s when QPSK modulation with a

symbol rate of 78 Msps is applied. The 106.3 Mbit/s transfer rate is realized when 8PSK modulation

with a symbol rate of 39 Msps (Mega samples per second) is applied. The antenna control

information, such as the reception level and antenna directional data, is stored in the control sections.

The modem signal and the error information of Bit Error Ratio (BER) or Packet Error Rate (PER)

(circuit quality) are also stored in the modem sections at both the airborne and ground stations. The

flight data, which consists of airplane location/attitude information, is stored only on the aircraft. The

ground station treats the transmitting and receiving data through millimetre waves.


Fig.4.1-1 Airborne verification test system

Table 4.1-2 Airborne verification test overview


(B) Experimental Configuration

Figure 4.1-2 shows the connection diagram on the aircraft. The aircraft system consists of antennas

for transmitting/receiving radio waves, a controller for directional control of the antennas, a modem

for modulating/demodulating data, and a power supply from the aircraft to each device. The on-

board antenna consists of transmission and a reception components using active phased array

antenna (APAA) technology, which is capable of two-dimensional electronic antenna scanning. The

APAA is composed of 64 elements in an eight-by-eight array. Each element of the APAA is

connected to the transmitting/receiving module to control the antenna beam direction by changing

the phase component with 4-bit resolution. In addition, the directional control of the antenna is

limited to +/- 45 degrees as a device specification.

The configuration of the control section allows the connection of the GPS and the gyro sensor

modules to acquire the location and attitude of the aircraft. The system computes the direction to

which the antenna should be directed in the very near future to command and control the antenna for

direction to a point from the past track of the flight path based on information from the GPS and the

gyro sensor. The modem is configured to allow switching modulation between QPSK and 8PSK

using a PC. The PC is also used as a file server.


Fig.4.1-2 Experimental configuration at the airplane side

4.1.4 Results

Table 4.1- 3 shows the items to be evaluated in the airborne verification test. Each item was

conducted using the test procedures shown in Figure4.1- 3. The following figures show the results.

Table 4.1-3 Airborne verification test evaluation item


Fig.4.1-3 Testing procedure

(A) Antenna pattern measurement

As shown in Figure4.1-3, the antenna pattern is measured on the basis of the reception level during

several passages of the airborne station exactly over the ground station. The antenna directivity of the

ground station is fixed straight upward and that of the airborne station is selected as either fixed

straight downward or in the programmed tracking mode during the passage by selecting patterns of

flight altitudes. The sampling interval for data acquisition is 0.1 seconds.

Figure 4.1-4 shows the results of antenna pattern measurements of the altitude of the aircraft, which

is approximately 900 m. The result of the measurement obtained in an anechoic chamber is also

depicted. As a result, the beam width of the antenna is observed at about 8 degrees in the airborne

test, while it is observed at 10 degrees in an anechoic chamber. Although the width becomes

approximately 2 degrees narrower than that of the designed value, the characteristics of the antenna

beam are almost identical. The difference in the peak values of the antenna beams is attributed to the

effect of the mounting error of the device or the influence of the fuselage.


Fig.4.1-4 Antenna pattern measurement result

(B) Tracking ability test

As shown in Figure4.1- 3, tracking ability was measured based on reception level during several

round trip passages of the airborne station over the ground station. The antenna directionality of the

ground station is fixed straight upward and that of the airborne station is selected as either fixed

straight downward or in a programmed tracking mode during the passage by selecting three flight

altitudes (2,500 m, 1,500 m, and 900 m). The sampling interval for data acquisition is 0.1 seconds,

and the airspeed is about 200 km/h. Figure 4.1-5 shows the reception level of the airborne station

antenna when fixed straight downward. Also, Figure 4.1- 6 shows the reception level of the airborne

station antenna in programmed tracking mode. The duration of the communicating segment, which is

specified as a segment from a point about 5 dB below the peak until that of 5 dB from the peak of

electrical power from this result, is approximately one when fixed straight downward and

approximately 3.5 seconds in programmed tracking mode. Programmed tracking mode is longer and

can be confirmed as tracking correctly. The maximum angular ground speed is 229.65 km/h at an

altitude of 785.47 m tracked at 4.7 degrees per second in calculation, which is confirmed as the

desired data to be obtained. Although restrictions on the flight altitude limit the value, a higher

tracking capability is ensured since APAA is performed during the electronic scan.


Fig.4.1-5 Reception level of airborne station with antenna fixed in straight downward

Fig.4.1-6 Reception level of airborne station with antenna in programmed tracking mode

(C) Communication capability test and mass volume data transfer test

Reception level and BER characteristics were obtained as shown in Figure 4.1-3 (2). The modulation

type during this acquisition is QPSK, and the flight altitude is approximately 2,000 m. Figure 4.1-7

shows the reception level and BER for the uplink. Similar results are obtained for the downlink as

well. Although the uplink and downlink have slightly different frequencies, the characteristics are

confirmed as almost identical. Indications of higher reception levels than the designed value during

uplink can be inferred as caused by the transmission signal of the downlink, which was reflected by


the dome and diffracted to the reception side. The BER of the uplink ensured a sufficient value even

under such conditions. The BER shown here is a BER before correcting errors so that it can be

improved by this correction. It succeeds in establishing communication for approximately 2 minutes

as well as in downloading a 500 Mbytes file in approximately one minute during this communication

establishment segment even in this environment.

In addition, a similar result was confirmed during the turning flight as shown in Figure 4.1- 3 (3).

During the turns, a test was conducted with modulation type QSPK, as well as switched to 8PSK. As

a result, characteristics identical to those during straight flight were obtained without dependence on

the modulation type. The system succeeds in establishing communication for approximately 20

minutes in the combination of QPSK and 8PSK type, as well as in downloading a 500 Mbytes file

for both the QPSK and 8PSK during this communication establishment segment of the flight. These

results can be considered verification of mass volume downloading with bidirectional IP

communication.

Fig.4.1-7 Reception level during uplink and BER

(D) Communication distance test

We calculated the communication distance from the result obtained in the test in (C). Figure 4.1-8

shows the results of the communication distance obtained during straight flight. The results indicated

that communication was established for a horizontal distance of 2,380 m and a flight altitude of

1,816 m, thus the communication distance was approximately 3 km. At this time, the angle of

elevation sighting the airborne station from the ground station is 38 degrees, which was confirmed as

a minor difference compared to the device specification of 45 degrees for the beam scan range of the


APAA used on the airborne station. This scan range influences the restriction of communication

distance. This result confirms that the communication distance corresponding to the beam scan range

of the antenna for an airborne station is ensured.

Fig.4.1-8 Communication distance calculation result (during straight flight)

4.1.5 Conclusion

The experiments regarding a broadband communication system for airplanes using the millimetre

wave (MW) band (40 GHz band) proved the effectiveness of broadband wireless communications in

airplanes and on the ground. The results confirm the success of the airborne verification test using a

small airplane. Application of this result to various aircraft shall establish an environment that

enables mass volume downloading with bidirectional IP communication. The range of application of

this system can be the aircraft Internet service on commercial airlines to a system handling volume

data, such as aerial surveys. It is also considered to be possible to apply the broadband

communication system to terrestrial communication system such a train communication system. Its

prospective future development is awaited.

4.1.6 Future challenge

We experienced a serious damage caused by the Great East Japan Earthquake in 2011. After such

damage, it is essential for relief, restoration and reconstruction from the earthquake to grasp the

situation. A broadband communication system for airplanes using the MW band can be used for

transmitting videos and pictures obtained by airplanes to grasp the damages in affected areas.


Therefore, we will explore the possibilities of applying the technology in a practical way for disaster

rescue and relief.

4.2 Case 2: wireless bridge system using small UAS

4.2.1 Background

The crisis of the 3.11 Great East-Japan Earthquake in 2011 reminded us that the most advanced and

popular mobile phones becomes almost useless under large-scale disasters due to physical damage,

electricity outage, and traffic congestion. The loss of communication caused confusion, bad decision,

and even increase of the number of victims in evacuation and rescue process. In addition, many areas

in mountains or islands were isolated due to the total damage of roads, harbors, and communication

infrastructures. Although such a disaster would not happen frequently, we cannot deny that the

earthquake or tsunami of about the same scale would hit populated metropolitan area in very near

future.

Based on the lessons learned from the above experiences, we started R&D on disaster-resilient

wireless bridge using small unmanned aerial system (UAS) in order to ensure the communication

infrastructure between the isolated and the non-isolated areas. The UAS and satellite link provides

temporal communication lines rapidly deployable to the isolated areas until the recovery of ground

infrastructures.

We developed the disaster-resilient wireless bridge using small UAS and the first demonstration test

of wireless bridge using UAS was successfully conducted in the end of March 2013. This document

provides a brief overview of wireless bridge using UAS and the report of experiments and

demonstration tests.

4.2.2 Wireless Bridge Using Small UAS

The small UAS used in the system consists of a small unmanned fixed-wing aircraft and ground

control station (GCS). The aircraft has an avionics computer system, two-way wireless control link,

and some sensors such as a GPS receiver, an acceleration sensor, a gyro sensor and an altimeter. It is

an autonomous aerial robot, which flies according to pre-programed waypoints and returns to a pre-

programed landing point after the completion of mission. Conventional manned aircrafts could be

used in the disaster situations not only for wireless relay and monitoring, but also for transportation

of people and goods. However, the cost to operate small UAS would be much lower than that for

manned aircrafts, if the mission is limited to wireless relay and monitoring.

The specifications of the small UAS are shown in Table 4.2.1. We can operate it even when the cars

are not available due to road damage, heavy traffic jam, or gasoline shortage since the aircraft and


GCS are easily hand-carried. In addition, special area such as runways is not needed for launch and

landing since it can be launched by throwing and recovered by deep-stole landing.

The UAS flies and circles around a certain point to provide a bridge between an isolated area due to

the damage of infrastructures and a survived area by on-board wireless relay station (OWRS). In

order to extend the range of the bridge, we can add another UAS to form a double-hop relay given by

the UAS-to-UAS direct communication link as shown in Fig. 4.2.1. Two ground telecom stations

(GTS) are setup on the ground using tripods: one is in the isolated area where the normal networks

are not available and the other is in the survived area where the GTS is connected to the Internet or

the private network. The users in the isolated area can access to the Internet or the private network by

using their own Wi-Fi terminals such as smart phones or PCs via a Wi-Fi access point delivered

along with the GTS. One UAS would cover an area of about 5 km in radius. Therefore the possible

communication range between two GTS would be more than 10 km with the double-hop formation.

The specifications and the view of the OWRS are shown in Table 4.2.2 and Fig. 4.2.2, respectively.

Fig. 4.2.1 Wireless bridge using UAS.

Table 4.2.1 Specifications of the small UAS.

Name PUMA-AE (AeroVironment, UAS)Wingspan, Weight 2.8m, 5.9kg

Payload 0.5kgFlight time, range 2-4 hours, 15-20 km

Wind speed 25 knots (13m/s)Max. flight celling 5000 m (200~400m in the demo)Power, operation Electric, hand launch, deep-stole landing,

autonomous flight by GPS and other sensors, water proof

Table 4.2.2 Specifications of the OWRS.

Frequency/Bandwidth 2.3 GHz/8MHz


TX power 2W

Modulation/MAC MSK/TDMA/TDD

Antenna λ/4 whip (omni-directional)

Number of hops Single or double

Air bit rate/Throughput(*) 6Mbit/s/500kbps

Synchronization GPS receiver in GTS

Size (w/o antenna) W90 x D100 x H116 (mm)

Weight 500g

Fig. 4.2.2 On-board wireless relay station (OWRS).

4.2.3 Measurement results

4.2.3.1. Sendai

First experiment on the relay communications using an unmanned aircrafts (UA) was conducted in

Sendai city, Miyagi prefecture, Japan, in March 2013. The purpose of conducting this experiment

was to measure basic characteristics on the system, including received signal strength (RSS) at

ground station (GS) during a flight, correlation of measured RSS with flight characteristics like

posture angles of the aircraft, and so on. Fig. 4.2.1 shows an illustration on the system’s deployment

at this experiment; two GSs, GS-A and GS-B, were deployed with distance of 900 meters. These

GSs are settled so that line-of-sight (LOS) with the UA is maintained along a pre-determined flight

route. The flight route of the UA is displayed by a red curve in Fig. 4.2.3-1. The altitude of the

deployed UA was set to around 170 meters against the ground level (AGL), and its radius was set to

around 100 meters.

A control station for the UA was located close to the GC-A, at which the average distance against the

UA is around 400 meters.


Fig. 4.2.3-1 System deployment for experiment on the relay communications using UA

conducted in Sendai city

As a measurement result, Fig. 4.2.3-2 shows RSS measured at the GSs while the UA were flying. As

shown in this result, the RSS is periodically changed due to the periodic flight route of the UA in this

experiment. This result suggests that characteristics of radio communications in UAS are highly

affected by its deployment that includes flight operation of UAs. From applications viewpoint, we

confirmed that the relay communications establishes communications link with throughputs of up to

500 kbps, and also web browsing with the Internet was achieved through the relay communications

with a UA.

Fig. 4.2.3-2 Received signal strength (RSS) measured at deployed GSs along the flight route

shown in Fig. 4.2.3-1.

4.2.3.2. Taiki-cho in Hokkaido

Second experiment on the relay communications using an unmanned aircrafts (UA) was conducted

in Taiki-cho, Hokkaido, Japan, in June 2013. The purpose of this measurement is to test the long

distance relay communication. Fig. 4.2.3-3 shows an illustration on the system’s deployment at this


experiment; two GSs, GS-A and GS-B, were deployed with distance of 1500 meters. These GSs are

settled so that line-of-sight (LOS) with the UA is maintained along a pre-determined flight route. The

flight route of the UA is displayed by a red curve in Fig. 4.2.3-3. The altitude of the deployed UA

was set to around 300 meters against the ground level (AGL), and its radius was set to around 100

meters. A control station for the UA was located close to the GC-A, at which the average distance

against the UA is around 400 meters.

As a measurement result, Fig. 4.2.3-4 shows RSS measured at the GSs while the UA were flying.

The RSS of this experiment is periodically changed due to the periodic flight route of the UA

similarly to the experimental 1. The average RSS of GS-B is 20 dB lower than that of the GS-A due

to the path loss decay. However, we confirmed that web browsing with the Internet was achieved

through the relay communications with a UA. It indicates he possibility that wireless bridge using

small UAS can realize the relay communication between the two GSs with distance of 3000 meters.

As a conclusion, the relay communications using UA was experimentally demonstrated that the

system establishes a communications for saving disruptive areas from network failures due to

massive disasters like earthquake, tsunami, avalanche, and so on.

Fig. 4.2.3-3 System deployment for experiment in Taiki-cho, Hokkaido, Japan


Fig. 4.2.3-4 Measured RSS level at the deployed GSs along the flight route shown in Fig.4.2.3-3.

4.2.4 Integration of wireless bridge using UAS and Relay-by-Smartphone

4.2.4.1. Applications and characteristic of relay-by-smartphone

By developing a novel multi-hop routing technology, a network architecture that can be used for

infrastructureless message transmission, “Relay-by-Smartphone” is created. Relay-by-Smartphone is

applicable in many situations, such as distributing advertisements or distribution of information

documents in meeting or conference. However, one application that it especially excels at is disaster

oriented network. Tragic disasters like tsunamis or earthquakes would often leave the affected areas

with damaged transportation infrastructure, insufficient power and water, and most importantly

damaged communication infrastructure. Without communication infrastructure, most communication

devices, such as cellular phones, laptop computers, or personal tablets, are rendered unusable. As a

result, disaster victims are unable to contact their family, friends, or associated authorities to report

their safety or request aids. Relay-by-Smartphone aims to solve this problem by establishing

infrastructureless communication from disaster victims’ mobile communication devices. When a

disaster victim participating in Relay-by-Smartphone system sends a message, the message will

propagates through other devices until the destination is finally reached. Thus, making message

delivery inside the disaster affected area possible. Additionally, Relay-by-Smartphone can also have

a special device, which acted as a gateway between Relay-by-Smartphone network and other

networks. Therefore, once the message arrived at the gateway, the message can be forwarded into

Internet or other network and thus making communication to and from outside network possible.


4.2.4.2. Integration of wireless bridge using UAS and Relay-by-Smartphone

The flexibility of Relay-by-Smartphone system means that it is possible to interconnect this system

with other communication network such as satellite communication systems, Unmanned Aircraft

Systems (UAS), and optical fiber networking. Similar to other wireless multi-hop networks, Relay-

by-Smartphone relied on network participants who are uncontrollable. As a result isolation problem

may surfaces when a Relay-by-Smartphone network is too far away from the closest gateway. Even

when isolation problem may not pose any problem for those that want to send message locally, it

prevent Relay-by-Smartphone network from delivering messages to the outside networks. However,

we can overcome the isolation problem by integrating Relay-by-Smartphone and UAS.

Unmanned Aerial Vehicles (UAVs) are automated aircraft of various shapes and sizes, which are

commonly utilized in reconnaissance, scouting hazardous areas, collect data from mobile sensors

networks, and so forth. We focus on an application of UAV referred to as Unmanned Aircraft

System (UAS) based relay system, which is a network made up of multiple UAVs interconnecting to

form an Adhoc like network that can provide communication services in a large area. With UAS

based relay system, multiple Relay-by-Smartphone networks can be connected through series of

UAV. Due to the extraordinarily large area coverable by UAS based relay system, it is very practical

to utilize UAS based relay system to interconnect multiple Relay-by-Smartphone networks. By

integrating multiple UASs and Relay-by-Smartphone networks isolation problem can theoretically be

eliminated through the placement of UAS’s base stations as shown in Fig. 4.2.4-5. The experiment to

show the practicality of this concept was conducted at Tohoku University’s Aobayama campus and

Katahira campus. Aobayama campus was assumed to be an area affected by disaster while Katahira

campus was assumed to be unaffected area as shown in Fig. 4.2.4-6. Additionally, each campus has a

ground station with a Relay-by-Smartphone gateway connected are deployed. The message was sent

from a participant at Aobayama campus and propagated through other participants’ smartphone

before arriving at the gateway. The message is then forwarded to PUMA-AE unmanned aerial

vehicle (UAV), which in turn transmits the message to the gateway residing at Katahira campus

resulting in a successful transmission over approximately 3 kilometers distance without any need for

infrastructure. Additionally it is observed that the delivery delay increases with the increase in data

size as shown in Fig. 4.2.4-6.


Fig. 4.2.4-5 An overview of a system integrating UAS based relay and multiple Relay-by-Smartphone systems

Fig. 4.2.4-6 An outline of the experiment conducted at Tohoku University to evaluate the

performance of Relay-by-Smartphone and UAS integration system

Fig. 4.2.4-7 Experimental result shows that deliver delay increases with the data size


4.2.4.3. Future considerations and conclusion

Relay-by-Smartphone system has significant potential in providing communication service in an area

without established infrastructure. However, many challenges still need to be addressed to achieve a

system that can serve in dire situation such as after disaster. Due to the diversity of mobile devices, it

is necessary to be able to make Relay-by-Smartphone work on different mobile devices, which may

have different hardware specifications or different operating systems. In order to unleash the full

potential of Relay-by-Smartphone, interconnectivity to other communication networks, such as UAS

networks need to be improved. Currently, essential functionalities, such as routing protocol are

implemented separately in both Relay-by-Smartphone and UAS networks. It is necessary to develop

a robust routing technology that integrates the characteristics of both Relay-by-Smartphone and UAS

networks in order to provide optimal performance when both systems are utilized to their full

potential.

In conclusion, Relay-by-Smartphone system is a practical infrastructureless communication system

aims to deliver message over a long distance. The system can be enhanced by interconnecting it with

other communication network such as UAS networks to further increase the coverage area.

4.2.5 Delay and Disconnection Tolerant Message Transmission System using UAS (in case of

using single Unmanned Aircraft UA)

4.2.5.1. Overview of delay and disconnection tolerant message transmission system

Due to natural disaster such as earthquake, tsunami and typhoons, it is feared that small villages,

which are in the mountain region, by the river or nearby shore, are isolated from other areas. The

Unmanned Aircraft Systems (UAS) will be useful for such extraordinary situation. In the initial state

of the disaster relief, available number of Unmanned Aircraft (UA) will not be enough.

This section describes the delay and disconnection tolerant message transmission system using the

single UA, which provides the exchange of the electric messages such as E-mails, short messages,

and files, between the surviving region and isolated area.


Dedicated MessageStorage

Internet

Surviving region

User Terminal(s)Shelter A

Temporary Wi-Fi APwith Message Storage

Wi-Fi

Wi-Fi Disaster area

UAS with Wi-Fi Router and Onboard Message Storage

Shelter B Shelter C

Wi-Fi, WiMAX, LTE

Figure 4.2.5-1 Overview of delay and disconnection tolerant message transmission system

Fig. 4.2.5-1 shows the overview of delay and disconnection tolerant message transmission system,

using the single UA. Herein, it is supposed at the shelter in the disaster area that temporary Wi-Fi

APs (Access Points) with the message storage are provided. In the surviving region, the dedicated

mail servers are operated to exchange the messages between the Internet and the disaster area,

through the UA. The UA has the functions of the Wi-Fi router and the message storage. The

communication between the ground and UA will start, when the UA comes into the coverage area of

Wi-Fi AP or WiMAX/LTE base station. By such network configuration, the delay and disconnection

tolerant system can be achieved. This system can rapidly work even just after the disaster

occurrence, therefore very important information can be exchanged and contribute to the rescue

operation.

On the shelter side in the disaster area, the operation of user terminal is the same as in daily use,

therefore no special technique and communication engineer is necessary. The UAS is so widely

useful for the residents in the disaster area.

4.2.5.2. Possible radio services and applications

(a) Use scenario

Figure 4.2.5-2 depicts examples of use scenario of the indicated message transmission system. The

aim of the system is to provide reliable communications among various facilities such as shelters,

city halls and hospitals, during the failure of infrastructure communications caused by the disaster.

When the disaster occurs, the communication function fails between the isolated disaster area and

surviving region. As aforementioned, the UA flies and conducts information exchange between those

areas. The information exchange is implemented by the Wi-Fi and existing devices such as smart


phones and PC. No additional communication devices are necessary. For example, smart phones can

be used to provide emergency information exchange for personal safety check and necessary medical

care. The Personal computer in the city hall monitors the water level and informs it to all shelters if

there is a risk of floods.

(b) Functions of the message transmission system

The message transmission system is intended to bring rapid relief to isolated disaster area caused by

disaster. The system should consist of several functions in the UA, isolated area and surviving

region. Only the surviving region has Internet capability. The UA should be equipped with very light

weighted and battery driven Wi-Fi router and message storage device. These devices should be

energy efficient to extend battery life of the UA. In the disaster area, such function is needed to

gather and store the resident messages via Wi-Fi and push them to UA. The function to receive

messages from the UA and distribute them to the proper user terminals, is also required. In the

surviving region, such function should be established that the server in the Internet is connected to

the Wi-Fi router in the UA. As this function needs no additional hardware, it can be equipped in the

cloud system for example.

shelter

hospital

city hall

Unmanned Aircraft (UA)

shelter

Mr. ABC is safe ?

Is there any shelter that needs blanket ?

FAX

personal smart phone

The water level of the river is so high. Inform it to all shelters !

PC for managementThere are many injured people.Is the doctor available ?

Figure 4.2.5-2 Example of use scenario

The protocol sequence of the message transmission system is shown in Fig. 4.2.5-3.For example, it is

supposed that the users in the surviving region (disaster countermeasures organization, person to

require safety confirmation, and so on) send the message to the end user in the disaster area. The

commercial mail server receives the message and transfers it to the temporary message storage.

Then, the messages are sent to the storage in the UA via radio connection when the UA comes in the

coverage range. The UA flies back and forth between surviving region and disaster area. When the

UA reaches the disaster area, the UA pushes the messages towards the temporary AP via the Wi-Fi


connection. Then, the AP saves the messages in the storage device, and the smart phone of the end

user picks the message via the Wi-Fi connection.

Step.1: The temporary message storage[A] in the surviving region receives messages from users (disaster countermeasures organization, person to require safety confirmation, etc) via Internet, which is directed for the users in the disaster area.Then, when UA comes in the BS service range,Step.2:The messages are sent to storage in the UASvia radio access (Wi-Fi, WiMAX, LTE etc.).

Internet TemporaryAP

BS

Step.3:UAS carries the messages toward the diasater area.

Step.4: UA pushes messages towards the temporary AP in the shelter via Wi-Fi.

Step.5: The AP saves the messages in the storage device equipped.

Step.6:From the AP, the smart-phone picked up the messages via Wi-Fi.

A

B

1

23 4

56

Note :Reverse direction (from disaster area to surviving region) is also configurable.

Figure 4.2.5-3 Protocol sequence of the message transmission system

4.2.5.3. Technical issues to be studied

(a) Establishment of message routing

In the indicated transmission system, the message is exchanged during the fling transfer of the UA.

Therefore, it is not easy to obtain the continuous end-to-end communications. The important

technical issues of the messages routing and message delivery confirmation are described as follows.

Messages routing

To send mails to users in the disaster area, it is necessary to manage locations of the user

terminals. This function can be achieved by referring to the access history of user terminals,

which is processed in the temporary message storage in the surviving region. Based on such

processed information, the destination of the message can be decided, which includes UA

identification number and disaster area number for example.

Message delivery confirmation

Although the message is transmitted according to the message routing scheme, the message

may not be received due to mobility of user terminals. Therefore, it is necessary to monitor

the message delivery confirmation. If the message is sent to improper destination, it is

required to retransmit messages to other UA and other disaster area.

(b) Wi-Fi direct connection between the UA and ground


As for the indicated system, we suppose that the dedicated relaying devices such as temporary AP

are deployed on the disaster area. In the future next system, direct communication between the user

terminal and the UA is envisaged. In such case, the following issues are needed to be considered.

The received power will be low when the height of UA is large of hundred meters and the

communication coverage is broad.

The UA will suffer from the interference from many terminals in broad area.

The hidden terminal problem will frequently happen.

The quality of the wireless link will drastically change due to high speed of the UA flight.

It will be necessary to measure the quality of the wireless link of the upper air to clarify

the difference between the ground and upper air, in the case of cloudy or rainy weather.

4.2.6 Hand-Over system of multiple ground stations in multiple unmanned aircrafts operation

4.2.6.1. Overview of hand-Over system of multiple ground stations in multiple UAs

Recently, with the progress of unmanned aircraft (UA) system technologies, some applications are

expected to expand to civilian use. It is also expected to expand the use of small and medium-sized

UA and operate it in a wide area in various fields including pesticide spraying, aerial survey,

logistics, environment observation, data collection for survey of animal and plant life, infrastructure

monitoring, and information collection at disaster. In the wide area operation of small and medium-

sized UA (Unmanned Aircraft), it is necessary to follow the flight situations of each UA (Unmanned

Aircraft) to secure the flight safety among multiple aircrafts (among UA, or among manned aircraft

and UA in the future) which share the air space. And accordingly, a simple and lightweight flight

control system should be considered for a flight control of small and medium-sized UA.

Figure 4.2.6-1 shows an overview of hand-over system of multiple ground stations in multiple UAs

operation. This system is composed of an on-board transceiver and access points (APs) for ground

control. This system monitors flight information and achieves a stable flight control in a wide area by

sequential hand-over of multiple APs placed along the flight path. Thus, it is possible to continuously

monitor multiple UA and safely control the flight by managing flight information of multiple UAs

obtained from plural APs in an air traffic control system.


Figure 4.2.6-1 Overview of hand-over system of multiple ground stations in multiple UAs operation

This section introduces a hand-over technology for the efficient use of frequency and the safe wide-

area operation required for the flight control system above. This technology enables the

implementation of a flight control system for a small and medium-sized UA which is unable to be

equipped with a large flight control system such as a satellite communication system or an ATC (Air

traffic control) transponder.

4.2.6.2. Example of operations and features

(a) Example of Operations

Figure 4.2.6-2 illustrates an example of operation of UA hand-over system. This system consists of a

control and non-payload communication (CNPC) system mounted on an UA and AP (Access Points)

for simple ground control placed on the ground level. Each AP is placed along the flight path of UA

on the ground so that its radio coverage overlaps that of adjacent AP. When UA approaches the

coverage of AP, the UA requests the AP to control flight and the AP keeps the flight information of

the UA, together with that of other UA within the coverage. When the UA moves to new adjacent

AP, the AP seamlessly hand-overs the information of UA to new adjacent AP, which monitors the

UA continuously.

AP follows the current position, velocity, direction, altitude, and identification number of plural UA

and transmits the information to an ATC system through a ground network system. Based on the

information, the ATC system directs the distance between UA, altitude, velocity, direction, and route

to a flight control system of each UA to enable safe and efficient UAS operations.


This system is intended for a small and medium-sized UA which is unable to be equipped with a

large-size flight control system such as a satellite communication system or an ATC transponder.

Therefore, on-board equipment for hand-over needs to be small, lightweight, and power-saving. For

widely using UAs, AP should be portable, inexpensive, and power-saving. Achieving this allows the

construction of flight control system enabling dynamic flight path setting to operate many UA

simultaneously. In the future, when UA shares the air space with manned aircrafts, the integrated

control of manned and unmanned aircraft can be attained by information sharing between the UA air

traffic control system and the manned aircraft air traffic control system.

Figure 4.2.6-2 Example of hand-over operation

(b) Features of hand-over system

The hand-over system is intended for safety flight and efficient operation of UA by always

controlling the beyond line-of-site (BLOS) wide-area operation of small and medium-sized UA.

Therefore, this system needs to have:

High spectral efficiency and power-saving ground equipment;

Single channel of 5GHz frequency band based on the agreement of WRC-12;

No cutoff during hand-over for safe flight control, such as wireless LAN;

No large-sized ground equipment;

Small-size, lightweight, and power-saving radio to be able to be mounted in a small and

medium-sized UA.

To meet these requirements, this system shall have the following features:

(1). Protocol that hand-over is available in single channel of 5GHz frequency band.

(2). Protocol that time-division multiple access (TDMA) and time division duplex (TDD)

where one-to-many communication is available for UA and AP.APT/AWG/REP-56 Page 30 of 45

Set-A Packet call with AP Set-C Packet call with APSet-B Packet call with AP

Initial packet call

(3). Reliable and seamless hand-over to new adjacent AP, by allowing UA to

communicate adjacent APs simultaneously in an overlapping communication area.

(4). To improve the robustness of communication continue the communication as long as

possible, not disconnecting the communication with the current AP immediately after

establishing the communication with the adjacent AP (See Figure 4.2.6-3 ).②

Figure 4.2.6-3 Example of basic hand-over by single UA

(5). Establish hand-over only by communication between each AP and UA without any ground

station such as a radio network control equipment that controls AP to control hand-over.

(6). Power-saving design. When there is no nearby UA for requesting hand-over, AP stops

sending to reduce power consumption.

This hand-over system is that UA sends a call to AP, and AP gives a transmitted packet to UA. Then,

using the packet, UA communicates with AP. Transmitted packet to be given to one AP is limited

and divided into three as shown in Figure 4.2.6-4. By dividing into three, hand-over can be done

without congestion (See Figure 4.2.6-5).

Figure 4.2.6-4 TDMA-TDD format of hand-over algorithm


①　　　　　　　　　　　 ②　　　　　　　　　　　 ③

Figure 4.2.6-5 Example of hand-over operation using TDMA-TDD format

4.2.6.3. Technical issues

(a) Adaptive control of transmission rate

According to situations of take-off and landing and collision avoidance of UA, image information

and sensor information necessary for flight control as well as airframe information are required to be

transmitted. However, in case of transmission through TDMA-TDD in limited frequency band, if

packets are fixedly applied to multiple AP or UA, the packets are fragmented and CNPC information

cannot be transmitted efficiently. It’s a challenge to develop a transmission rate adaptive control

system which transmits the most appropriate CNPC information amount effectively in the limited

band and frequency.

(b) Automated setting of APs

In the UA hand-over system we introduced here, it is necessary to locate AP along the flight path in

the predetermined order. However, when a path is extended or urgently set due to, for example,

disaster, AP should be located without any mismatch of relation between setting and location for

each other. It’s a challenge to develop a function to set AP automatically without any restriction.

5 The potential radio services and applications on-board vessel

5.1 Case 1: Wireless Broadband Video Transmission Systems

5.1.1 Background and Application Requirements

The maritime transport regulatory systems includes Vessel Traffic Service(VTS) and Automatic

Identification System (AIS).Such systems provide great help for administration routines. But there

are certain deficiencies in these systems. For example, there are cases that the VTS radar is often

influenced by the horizontal width of the beam, which result distorted images, and cases that radar is

susceptible to interferences like the thunder and snow clutter, sea clutter, identical frequency clutter.

Therefore, the scan will be easily blocked by the object so that a blind spot will come out.

When the dangerous accidents take place in waters far away from the ports, the search and rescue

coordination center will fail to offer accurate instructions based on the actual situations. To improve


this situation, we need the other systems as a complement of the maritime traffic regulation, and the

wireless broadband video transmission systems will be a good choice. With the wireless broadband

video transmission system, we are able to know exactly in real time what is happening to the vessels,

to find disasters or hidden troubles as soon as possible, and to provide the basis for rapid decision-

making of the coordination center.

The wireless broadband video transmission systems should be capable of safe and reliable

transmission of video signals (including speech signals), and at the same time should be able to

ensure stable operation of the mobile terminal with excellent performance in a high-speed voyage.

We has made some attempts on the wireless broadband microwave transmission, and have performed

practical application in the search and rescue drills of the vessels in distress.

5.1.2 System Description

China has constructed a set of wireless broadband access communication system for the maritime

video transmission in Dalian Port area, which is composed of four base stations, a number of vessel-

borne or vehicle-mounted mobile terminals and servers as described in figure 5.1-1. The system take

use of advanced non-line-of-sight (NLOS) wireless broadband transmission equipment, non-line-of-

sight (NLOS) radio base stations and mobile terminals supporting 5.8GHz and several other

microwave bands, in application of OFDM-4/16/64QAM modulation scheme and a time division

duplex (TDD) transmission protocol, with a maximum output power of 5W for base station, 2W

for mobile terminal. It achieves a good signal coverage within 20 nautical miles away from the

coastal line, with a data transfer rate up to 2Mbits/s. The main advantage of the system follows that a

mobile terminal can ensure a real-time transmission of multimedia information back to the

coordination center in a state of high-speed mobile, so as to provide a convenient link for decision

making for command and dispatch and distress relief.


Vessel 1 Vessel N

Base-station3,4

Base-station1,2

Coordination Center

Server

Fig.5.1-1 Wireless Broadband Video Transmission System Diagram

5.1.3 Service Provider Cases

The wireless broadband video transmission systems had been applied in joint maritime search and

rescue drills in recent years, providing a command ship, a vessel in distress, two search and rescue

ships and a helicopter with wireless data transmission ，Specific configuration is as follows:

Command ship: a wireless transmission base station, a set of signal processing equipment, 1 video

camera .Vessels in Distress: a mobile terminal, two sets of signal processing equipment, 2 video

cameras. Search and Rescue ships: a mobile terminal, one set of signal processing equipment, 1 fixed

video camera. Helicopter: a mobile terminal, two sets of signal processing equipment, 1 video camera.

In such a search and rescue drill, the command ship can accurately locate of the vessels in distress and

the surrounding situations by the received wireless video signals from the vessels in distress, search

and rescue vessels and helicopters, and through the wireless broadband video transmission system to

carry out a successful rescue of the vessels in distress. The wireless broadband video transmission

system plays an important role in the exercise.


Fig.5.1-2 Wireless Broadband Video Transmission System for Maritime Rescue Exercise

5.1.4 Market Trend

From a technical perspective, the video technology and wireless transmission technologisare already

quite mature, with lower construction cost.

The maritime wireless broadband video transmission can effectively enhance the safety of the vessels,

to provide a basis for decision making for search and rescue of the vessels in distress. The maritime

wireless broadband video transmission is the inevitable trend of the development of maritime transport

safety communication, and has a broad market prospect.

5.1.5 Future challenges

With the tremendous development of maritime transport, fisheries, and maritime mining operations,

etc. the wireless broadband video transmission system which can report the situation in real-time will

be used more and more frequently. However, the smaller transport vessels and fishing boats cannot

afford a wireless video transmission system. A larger market size should be able to reduce the cost.

While the large vessels with the systems mentioned above can only realize the video transmission in

the waters within 20 nautical miles offshore . The satellite transmission can be an alternative.

However, as the cost is much higher, it is difficult to promote the use of satellite links on the vessels.

Since better communication quality, lower communication cost, and longer communication distance

are the eternal theme and challenges for maritime radio communication, Innovative systems and state-

of-the-art communication technologies are summoned to meet the demands.


5.2 Case 2: Maritime Broadband Multi-hop Relay Communication System

5.2.1 Background and Application Requirements

Nowadays, the demand for the various broadband multimedia services in the telecommunications

industry has increased and is intensified sharply due to smart phones. This trend toward faster data

transmission rate and broader frequency band than the existing systems in the terrestrial wireless

communication environment also applies in maritime communication environment. Some wireless

communication infrastructures in littoral zone are necessary in order to provide broadband

multimedia services between ship and ship or between ship and shore to conform to this trend.

Many ships have the facilities to provide the maritime wireless communications service in MF, HF

and VHF frequency bands, and/or to provide satellite communication services. And also some ships

in a few km from the coast within the service coverage of LTE or WCDMA are able to use the

terrestrial mobile service such as LTE or WCDMA. However, the frequency bands of MF, HF and

VHF communication systems are too narrow to provide the broadband multimedia services, the

satellite communication systems are too expensive to provide the broadband multimedia services

freely, and the communication coverage of LTE or WCDMA systems can’ t be beyond several km.

The maritime broadband multi-hop relay communication system proposed by Korea has the

characteristics that are able to provide up to 100km of the communication coverage in littoral zone

and 1Mbit/s of end-to-end transmission data rate with low cost of the communication services.

Most of ships are operated at around 30km from the coastline, but there is a need to expand the

communication coverage to protect ship accidents in offshore, especially in open seas and to test new

building ships in the area around 100 km off and to send the test data to the ship building yards. The

ship's safety and economic operation and ship management services for a variety of applications are

considered based on this maritime broadband wireless data communication and the data exchange

protocols.

5.2.2 System Description

The maritime broadband multi-hop relay communication system and the ship’s safety related

services have been developing by ETRI in Korea for 4yeas since December 2010. The final goals of

this project are to implement the wireless system which is able to operate in the frequency band of

2.4/5.8 GHz and to have the characteristics of the communication coverage of 100km from the

coastline and the end-to-end data transmission rate of 1 Mbit/s at least.

The concept diagram of maritime broadband multi-hop relay communication system is shown in

Fig.5.2-1.


Fig.5.2-1 Concept Diagram of Maritime Broadband Multi-Hop Relay Communication System

In these goals, the system is adopted the multi-hop relay scheme to expand the communication

coverage of 100km, and applied to the two wireless communication schemes such as the terrestrial

mobile communication scheme (LTE or WCDMA) and IEEE 802.11a scheme (WLAN) for the

transmission capacity. LTE or WCDMA scheme is applied to access between shore and the first ship

for data transfer and W LAN scheme is used between the first ship, called by Master Ship Station

(MSS), and other ships, called by 1st Slave Ship Station (SSS), 2nd Slave Ship Station, and 3rd Slave

Ship Station and so on. The configuration diagram of this system is as follows:

Fig.5.2-2 Configuration Diagram of the Maritime Broadband Multi-Hop Relay Communication

System

The maritime broadband multi-hop relay communication system is composed of 2 sub-systems

largely such as Control Station on shore and number of Ship Stations at sea. Control Station is to

control, monitor and manage Ship Stations, and a maritime broadband multi-hop relay


communication network on shore, and Ship Station is to send and receive user’s information to

several Internet portal servers or Control Station and several control signals from Control Station on

shore, respectively. Each Ship Station is again consist of 3 modules which are a communication

module toward land which has a LTE or WCDMA function for Master Ship Station and WLAN

function for Slave Ship Station, a communication module toward the sea which has a WLAN for

Ship Station, and a bridge module which can connect between LTE or WCDMA communication

module and WLAN communication module and between WLAN communication modules. The

characteristics for this system are as follows:

Table 5.2-1. Characteristics of the Maritime Broadband Multi-Hop Relay Communication System

Items Characteristics Remark

Data transmission rate Min. 1 Mbit/s end-to-end

Communication coverage 100 km from onshore

with the multi-hop relay

Ship speed <= 15 knot <= 30km

RF Frequency band 2.4 GHz / 5.8GHz WLAN frequency band

800MHz / 1.8 GHz / 2.1 GHz LTE frequency band

RF Power 1W 0.1W for 2013

Multiple access

Modulation scheme

Multiplex

OFDMA

QPSK/16QAM/64QAM

TDD

WLAN

(commercial products available)

OFDMA/SC-FDMA

QPSK/16QAM/64QAM

FDD/TDD

LTE

The terrestrial communication schemes can be applied to the same way as the maritime

communication systems because of having a sufficient performance for the performance of the

maritime communication.

5.2.3 Verification test

5.2.3.1. Configuration for the test

The verification test of the maritime broadband multi-hop relay communication system was

conducted through measuring the throughput of the above system on October 2013 near offshore of APT/AWG/REP-56 Page 38 of 45

Okpo in Geoje Island which is about 400 km southeast away from Seoul. The test configuration is as

shown in Fig.5.2-3. The test was conducted at 4 Test Points (TP): TP1 and TP2 were the first WLAN

base station at the top Oknyeobong peaks and the second WLAN base station at the top Seoyimal

lighthouse about 6km away from Oknyeobong peaks, respectively. TP3 and TP4 were the first ship

station and the second ship station in a drillship, respectively. The test was performed on three

routes. The first test was one-hop route (e.g. TP3 →TP2, TP4→TP2 and TP2→TP4), the second test

was two-hop route (e.g. TP2 →TP3 →TP1) and the final test was three-hop relay route (e.g.

TP4→TP2→TP3→TP1). The throughput was measured in the drillship using IPERF tool. And also

the test of internet access to various Internet portal servers was performed. On the other hand, the

LTE throughput tests of the commercial mobile services (LTE or LTE-A) weren’t conducted due to

the limitation to control the coverage of the mobile base stations over the coast.

Fig.5.2-3 Test Configuration for the Maritime Broadband Multi-Hop Relay Communication

System

A terminal of the maritime broadband multi-hop relay communication system was installed in each

TP, which consist of Bridge module, Modem module, and RF and Antenna module (See Fig.5.2-4).

The antenna installed in the drillship is shown in Fig.5.2-4 and the antenna in the tugboat had the

same configuration as in the drillship.


(a) System Configuration (b) Antenna

Fig.5.2-4 System Configuration and Antenna installed in Drillship

5.2.3.2. Results of the experiment

The results of throughput measurement using IPERF for one-hop route, two-hop route, and three-hop

route are as shown in Fig.5.2-5. The throughput in one-hop route is from 1.07 Mbit/s to 7.47 Mbit/s.

The throughputs in two-hop route and three-hop route are 1.03 Mbit/s~2.87 Mbit/s and 1.13

Mbit/s~2.55 Mbit/s, respectively. The results indicate that three-hop wireless relay in the maritime

broadband multi-hop relay communication system could achieve throughput over at least 1 Mbit/s,

though it has a wide span due to drift status and/or other passing ships around the drillship at the

time. It is expected that the coverage of the maritime broadband multi-hop relay communication

system would increase as wide as the coverage of LTE or LTE-A if terminals of LTE or LTE-A be

participated in the test.

Fig.5.2-5 Throughputs measured by IPERF


5.2.4 Application Services

The application services can include the safe related services of ship’s operation which are to

monitor the fire detection of ship and the equipment state of ship, to manage and estimate the engines

of ship remotely, to update the nautical charts automatically and to control ship arrival and departure

safely. An application service to test for the new building ships at sea can also be considered to

exchange the data and the information through this system for ship building yards. Further, the

broadband wireless communication infrastructures can be applied to provide the control and monitor

services between the offshore plants 200 or 300 km away and the control centers on shore and to

give the Internet services between the offshore plants and Internet portal servers on shore with lower

cost.

5.2.5 Market Trend

IMO (International Maritime Organization) has been leading to make of IMO’s policy for e-

Navigation for safety and security at sea and protection of the marine environment until 2014. E-

Navigation can be achieved from the key infrastructures which are called 4S (ship-to-ship and ship-

shore). In the near future, large ships more than 300 tons have to be built 4S communication

infrastructures in accordance with the International Sailing Rules. And also many small ships below

300 tons don’t have the communication equipment in terms of cost and security, but they have also

risk of an accident because of this. Therefore it’s important for small ships that the cost of building

the wireless communication equipment would be low.

This maritime broadband multi-hop relay communication system can be consistent on the

requirements for e-Navigation. Various ship safety and security services can be provided through the

maritime broadband multi-hop relay communication system to ship-to-ship and ship-to-shore. In

addition, this system would be contributed to the realization of e-Navigation policy, the cost

reduction for communication services and the welfare improvement in ship from the current

communication environment with high-cost and low-data transmission rate.

5.2.6 Future challenges

The need for the maritime broadband wireless communication infrastructures is increasing, but there

are a lot of challenges to overcome in terms of technical aspects and non-technical aspects to provide

the maritime broadband wireless communication services.

There are the technical challenges to solve as follows:

- Propagation characteristics analysis at sea in UHF band(e.g. frequency band above 1 GHz):

There are few reports on the analysis of propagation characteristics at sea in UHF band. That is, it

is difficult to estimate the attenuation of signals and to simulate the transmission RF channels at

sea


- Propagation tracking and maintenance technologies:

Ships are constantly moving at sea though there are some differences depending on the sea and

weather conditions. In order to send the signal to the destination stations (Control Station on shore

or Ship Station at sea) seamlessly, it needs to maintain an autonomous movement of the ships due

to the motion of the antenna.

- RF and antenna technologies:

HPA and LNA for 2.4/5.8 GHz frequency band and the MIMO design technologies to expand the

communication coverage

- Mobile IP technologies :

The Mobile IP routing and networking technologies need to maintain the connectivity between

Ship Stations seamlessly and to connect the other new route quickly instead of the disconnected

route in the environment of the unstable maritime wireless networks.

- Buoy or relay facilities at sea:

Most of ships are moved within 30km from the coastline and any ships within this range can be a

relay station. However, there are few ships beyond 30 km and it’s difficult to find a relay station.

Buoy systems, lighthouses and son on are ones of the candidates for the relay station.

In the non-technical aspects, any frequency allotments to the maritime broadband wireless services do

not exist for services providers to do business. It would be taken a long time, but it’s necessary to allot

the frequency bands for the maritime broadband wireless communication services.

6 Summary

6.1 Summary of the potential radio services and applications on-board aircraft

As the first case of the potential radio services and applications onboad aircraft, a broadband wireless

communication system using millimetre wave between airplane and ground was introduced. As the

demand for better mobile phone and Internet access for people on-board aircraft has increased,

several airlines have started cabin use of cellular phones, personal computers and smart phones with

a system involving satellites. A new system for airplanes using the millimetre wave band (40 GHz

band) was introduced to realize the broadband wireless communications between airplanes and the

ground. Several experiments using the proposed system were conducted and proved the effectiveness

of broadband wireless communications in airplanes and on the ground. The range of application of

this system can be the aircraft Internet service on commercial airlines to a system handling volume

data.

As for the second case, wireless bridge system using small unmanned aircraft system (UAS) and

several possible radio services and applications using UAS were introduced. The wireless bridge


system can establish a communications link for saving disruptive areas from network failures due to

massive disasters like earthquake, tsunami, avalanche, and so on. Moreover, the integration system

that combines the wireless bridge system with Relay-by-Smartphone was introduced. It was shown

that the coverage area of radio service could be enhanced by the integration system. As possible

radio services and applications using UAS, the delay and disconnection tolerant message

transmission system and the hand-over system of multiple ground stations in multiple UAs were

introduced. The delay and disconnection tolerant message transmission system can rapidly work

even just after the disaster occurrence, therefore very important information can be exchanged and

contribute to the rescue operation. On the other hand, the hand-over system can be able to

continuously monitor multiple UA and safely control the flight by managing flight information of

multiple UAs obtained from multiple access points in an air traffic control system in order to operate

small UA in various fields including pesticide spraying, aerial survey, logistics, environment

observation.

6.2 Summary of the potential radio services and applications on-board vessel

The wireless broadband video transmission system was introduced as the first case of the potential

radio services and applications on-board vessel. To improve the performance of maritime traffic

regulation, the wireless broadband video transmission system was introduced as a complement of

existing maritime transport regulatory systems including Vessel Traffic Service (VTS) and

Automatic Identification System (AIS). The proposed system is capable of realizing safe and reliable

transmission of video signals (including speech signals) as well as providing stable operation of the

mobile terminal with excellent performance in a high-speed voyage. Results from experimental

system shows that real-time transmissions of video signals from high-speed mobile terminals back to

the coordination center. Thus, convenient links are built to help decision making for command,

dispatch and distress relief.

The second case of the potential radio services and applications on-board vessel, the maritime

broadband multi-hop relay communication system, has also been introduced. As the demand for

various broadband multimedia services in the telecommunications industry increases, faster data

transmission rate and broader frequency band are required in not only terrestrial wireless

communication environment but also maritime communication environment. Following this trend,

the maritime broadband multi-hop relay communication system is proposed to provide broadband

multimedia services between ship and ship or between ship and shore. The proposed system is able

to provide high end-to-end transmission data rate with low cost of the communication services, and

more importantly large communication coverage to protect offshore accidents for ships in littoral APT/AWG/REP-56 Page 43 of 45

zone. The maritime broadband multi-hop relay communication system and the related services have

already been developed. Experiments verified the effectiveness of maritime broadband multi-hop

relay communication system through throughput measurements.

7 References

[1] Document AWG-12/INP-81 “Proposed update terms of reference and workplan of task group

aeronautical and maritime”, by PT Telekomunikasi Indonesia, Indonesia, China, April 2012.

[2] Document AWG-13/INP-10 “Report of studies for modern wireless technologies on-board

aircraft and vessels using the millimetre wave broadband wireless communication system”, by

NICT, Japan and Mitsubishi Research Institute, Inc., Vietnam, September 2012.

[3] Document AWG-13/INP-72 “The proposed structure of the working document towards

preliminary draft new report of the possible radio services and applications on-board aircraft and

vessels”, by China, Vietnam, September 2012.

[4] Document AWG-13/TMP-13 “Meeting report of task group on aeronautical and maritime”, by

Chairman, Task Group – Aeronautical and Maritime, Vietnam, September 2012.

[5] Document AWG-14/INP-10 (Rev.1) “Propose modification to working document towards


vessels”, by NICT, Japan and Mitsubishi Research Institute, Inc., Thailand, March 2013.

[6] Document AWG-14/INP-54 “Proposed modifications of the working document towards draft

new apt report of the possible radio services and applications on-board aircraft and vessel”, by

China, Thailand, March 2013.

[7] Document AWG-14/INP-73 “Proposed modifications to working document towards preliminary

draft new report of the possible radio services and applications on-board aircraft and vessels”, by

China, Thailand, March 2013.

[8] Document AWG-15/INP-38 “Propose modification to working document towards preliminary


Japan, Thailand, August 2013.

[9] Document AWG-15/INP-62 “Proposed addition for working document towards preliminary


Republic of Korea, Thailand, August 2013.


[10]Document AWG-16/INP-54 “Propose modification to working document towards preliminary


Japan, Thailand, March 2014.

[11]Document AWG-16/INP-95 “proposed modifications to working document towards a


vessels”, by Republic of Korea, Thailand, March 2014.


Documents

Introduction - Asia-Pacific · Web viewCurrently, essential functionalities, such as routing protocol are implemented separately in both Relay-by-Smartphone and UAS networks. It is