Disaster Communication Assistance Concept Paper

8/3/2019 Disaster Communication Assistance Concept Paper

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Concept Paper on

Emergency Communications during Natural Disasters:Infrastructure and Technology

To be carried out by: Broadband Mobile Communications Research Lab (BMCRL),

Asian Institute of Technology, Bangkok, Thailand

Overview of Research Conducted at Present/Expertise: Carrying out research for the

next generation Mobile Communications covering the physical layer aspects, especiallymultiple access techniques, high spectral transmission methods and advanced error

control techniques. The data rates in new mobile networks are expected to be in the range

of 100 Mbps - 1 Gbps. Given the unreliable nature of the mobile channel and different

propagation environments that depend on the carrier frequency, cellular architecture anda host of other factors, there is a strong demand for new methodologies needed in the

physical/Radio layer.

The research conducted is expected to provide detailed analysis of performance for newmultiple access techniques, capacity of multi-user systems, and new transmitter/receiver

configurations for a variety of channels. Multimedia research will look in to new methods

of image/video compression. Transmission of multimedia content over mobile channels

is a challenging task with increased data rates and hostile channel conditions.

In addition, aspects of data security are expected to be addressed as security plays an

increasingly important role. There is a need to investigate new encryption algorithmsgiven the computational powers of present day computers which may lead to attacks oncritical data. More importantly, the development of these algorithms would make sure

that there is sufficient know how is available given the proprietary nature of developed

algorithms.

Context in Disaster Communications:

Disaster Warning:

Here the main principle is to have sufficient lead time so that people can take measure to

prevent or minimize damage. The warning could be provided in terms of a signalappropriately channeled to provide either some visual indication of the impending

disaster or in audible form like sirens. The signal has to come from or generated from

detection equipment (sensors for earth quake, storm, flood, tidal wave or Tsunami). This

then can be picked up by some satellite networks in some dedicated emergency channeland/or through the mobile telephone networks (Base Stations), provided it is sent in the

proper format and then broadcast in an emergency channel. At the signal receiver end,

there should be sufficient identification to differentiate the warning signal. Once

identified, the receiver will then generate the required alarm. The receivers can bedistributed over the warning area (here, the idea is automation. No delay in decision

making or no answer due to holidays etc.).


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In some cases, detection equipment is distributed over different geographic areas. In suchcases, the signals from different areas can be collected using the same transmission

method described above, e.g. the telephone network, to a common receiver who interprets

the data and makes a decision whether or not to generate and broadcast a warning alarm.

The objective here is to identify the modifications needed in the existing communications

architecture and protocols to obtain and transmit the warning signals and the design of thereceivers capable of picking up the signal.

A. Disaster Warning

Proposed Actions

1. Signal generation from detection equipment2. Establishment of methodology for the satellite network to pick up signal3. Set up a procedure for Terrestrial/mobile networks to obtain the signal4. Broadcasting the signal5. Distribution of receivers geographically to obtain the Alarm6. Identification of the warning signal and Alarm generation

After the Disaster:

Disasters can not be prevented. But through proper warnings and disaster-after recoveryprocedures, the effects can be minimized. The collapse of communications infrastructure

is the usual effect of disaster, due to the collapse of antennas, buildings, power etc. But,

immediately after the disaster, due to emergency, communications are vital. There are

two aspects in this scenario. One is to immediately locate the affected persons andprovide emergency assistance. The other is to provide disaster relief during and after the

disaster.

In both scenarios we have to assume that most of the local communication infrastructure

would be unavailable. For example, some base stations may be destroyed.

Therefore the main idea is to look into the following issues in detail and to come up withdetails for suitable implementations.

Tracing of survivors- This can possibly be done assuming the availability of a mobilephone with the person(s) affected. In this case, it may be possible to establish a

communication link using

a) Base stations which are not destroyed - Here the surrounding base stations can beasked to interrogate the mobile stations that they see and provide that information to a

central monitoring station.


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b) In the absence of active base stations, it might be possible to devise a scheme totransfer the local cellular layer to a higher layer, possibly consisting of a satellite.

For this scheme to be possible, layered architectures should be considered. In addition,most important aspect would be how a regular mobile phone could be detected by a

satellite. It is proposed that methodologies for this must be investigated. This may include

having high power emergency channels available in the satellite, add-on extendableantennas for the mobile phone, hardware/software reconfiguration in the mobile etc.

In the cases where adding the satellite feature to each regular mobile phone is tooexpensive, we can consider an alternative network architecture. In this architecture, a

small subset of local users, e.g. police and town officials, carry mobile phones that are

satellite capable. The other mobile phones are modified so that they can communicate

with these satellite capable phones, forming an ad-hoc network when the base stations areall destroyed. This alternative architecture enables cost sharing of the satellite

communication links among multiple users in the same area. In addition, the cost of

modifying a mobile phone to be ad-hoc network capable is expected to be less than the

cost of modifying a phone to be satellite capable.

Tracking: It would be extremely helpful, if the position of the affected persons can be

located. Possibility of location by GPS should be investigated. The underlying

assumption is that the power available in the mobile phone is limited and how thecommunication must be established under adverse conditions.

B. Post-Disaster Communications

Tracing of Survivors

Proposed actions (availability of a mobile)

1. Establishment of a procedure for the surviving Base stations to interrogate mobilestations in the vicinity

2. Collection of those information in a central station3. In the absence of Base stations

Establishment of a procedure for the mobile to be detected by a satelliteOR

Integration of the mobile to a network with satellite capable equipment Ad Hoc Net work

4. Location Identification


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Communications for Emergency Management:

This would be to investigate a last mile wireless high-speed communications system to

support emergency management. The system will utilize surviving network infrastructureto provide network connectivity to emergency management field workers for applications

such as Geographic Information System (GIS) access and audio/video conferencing.

The issues to be looked at are designing the system architecture, developing and/or

integrating radio, link, network, and application-level hardware and software, and

exploring GIS applications. An important element of the work is rapid deployment, so

equipment must be portable, easily configured, and able to access remote databases andGIS engines.

It may be also an opportunity for Radio Local Area Network (RLAN) technology. Lowpower requirements, low cost, portability, point- to-point, point-to-multipoint and

multicast capabilities, coupled with high bandwidth, make RLANs an excellenttechnology for "on- the-spot" emergency communications.

C. Communications for Emergency

Proposed actions

1. Design of a system architecture for integrating surviving infrastructure2. Establishment of a broadband wireless communication system3. Provision of services required for the field workers

Sustainability:

It is expected that this project will generate interest among the authorities dealing in

disaster situations through dissemination of information through website, publications

etc. The lab will therefore can work in long term expertise development in this areawhich can provide the required knowledge to local scenarios.

This will help in attracting good quality students to work in this crucial area as there have

been several large scale disasters recently. The ability to manage communications wouldbe a great advantage to the South/South East Asian Region.


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System Illustrations of Emergency Communications

Pre-Disaster Communications: Disaster Warning

Prior to a disaster, the main function of emergency communications is disaster warning.We outline the main steps in the disaster warning process below.

1. Sensors employed in the field transmit local environmental information at regularintervals to the data processing center. For example, seismic sensors transmit

earthquake related information that can be used for warnings about earthquakes

and/or tsunamis. The communications can be done via wireline, wireless, or satellite

transmission. Fig. 1 illustrates communications from sensors to the data processing

center.

sensor data

processing center

(24-hr monitored)

sensorsin the field

satellite

wireless satellitereceiver

wireline

sensor data

processing center

(24-hr monitored)

sensorsin the field

satellite

wireless satellitereceiver

wireline

Fig. 1: Data transmission from sensors to the processing center

2. The sensor data processing center, which we assume to be monitored by humans 24hours a day, analyzes the sensor data and makes a decision whether or not disaster

warnings should be issued. Note that this decision is done by humans and notautomated.

3. If the decision is to issue warnings, then the warning information will be distributedwith no human involvement beyond the data processing center. The warnings can

reach the individuals in the disaster area via wireless or wireline transmission, or bythe use of visual/sound alarms. Fig. 2 illustrates communications from the data

processing enter to individuals in disaster related areas


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sensor data

processing center

(24-hr monitored)

individuals

wireless(radio,

SMS, etc.)

wireline (cable TV,

Internet, etc.)

visual/soundalarms

relateddisaster

area

satellites

disasterarea

sensor data

processing center

(24-hr monitored)

individuals

wireless(radio,

SMS, etc.)

wireline (cable TV,

Internet, etc.)

visual/soundalarms

relateddisaster

area

satellites

disasterarea

Fig. 2: Transmission of disaster warnings

Our technical contributions will involve how the warnings can be distributed throughexisting communication infrastructure with only slight modifications of the existing

systems, and with no human intervention required. For example, if the warnings are

distributed using SMS messages in cellular systems, we may be able to use the control

channels as communication channels in case of emergency. A part of our study is toinvestigate in detail how to do so.


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Post-Disaster Communications: Disaster Recovery

After the disaster such as an earthquake or tsunamis, we expect that some or all

communication infrastructure in the disaster related areas are destroyed. The main

function of emergency communications is to set up communication networks so thatsurvivors can establish a contact or can be located by the rescue teams through common

electronic devices such as cellular phones.

We outline three possible strategies for setting up emergency communication networks

below.

1. In the case that some base stations of cellular networks remain after the disaster, wecan utilize the remaining base stations. However, for emergency communications, wewill need to change the transmission scheme (e.g. different frequency band, higher

power, etc.) for larger coverage areas. In addition, a local police station may beequipped with a radio base station that can also be used to set up the emergency

network. For emergency communications, the mobile phone units must be able tooperate in the emergency mode with a compatible transmission scheme. Fig. 3

illustrates emergency communications based on surviving base stations from the

cellular phone systems.

(a) before the disaster

basestation

coveragearea

indi-vidual


basestation

coveragearea

indi-vidual

(b) after the disaster

remainingbase station destroyed

basestation

indi-vidual


remainingbase station destroyed

basestation

indi-vidual


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(c) after the disaster with police base station

remaining

basestation

destroyedbasestation

policebase station

indi-vidual

(c) after the disaster with police base station

remaining

basestation


policebase station

indi-vidual

Fig. 3: Emergency network based on the remaining cellular base stations as well as

police base stations, if any.

2. The above strategy based on using the remaining base stations may not be applicablewhen all base stations are destroyed. In this case, one possibility is to use satellitecommunications for each survivor. For this scheme to be possible, a regular mobile

phone needs to be able to communicate with a satellite. The modifications of existing

systems may include having high power emergency channels available in the satellite,

add-on extendable antennas for the mobile phone, and hardware/softwarereconfiguration in the mobile units, and so on. Fig. 4 illustrates emergency

communications based on a direct contact between each survivor and a satellite.


basestation

coveragearea

indi-vidual



indi-vidual

satellite


basestation

coveragearea

indi-vidual


basestation

coveragearea

indi-vidual



indi-vidual

satellite



indi-vidual

satellite

Fig. 4: Emergency network based on direct satellite communications.


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3. In the cases where adding the satellite feature to each regular mobile phone accordingto Fig. 4 is too expensive, we can consider an alternative network architecture. In thisarchitecture, a small subset of local users, e.g. police and rescue officers, carry mobile

phones that are satellite capable. The other mobile phones are modified so that they

can communicate with these satellite capable phones, forming an ad-hoc networkwhen the base stations are all destroyed. Fig. 5 illustrates emergency

communications based on the use of ad-hoc networks.


basestation

coveragearea

indi-vidual


destroyed

basestation

indi-vidual

satellite

satellitelink

ad-hocnetwork

link


basestation

coveragearea

indi-vidual


destroyed

basestation

indi-vidual

satellite

satellitelink

ad-hocnetwork

link

Fig 5: Emergency network based on an ad-hoc network

We note that the above three strategies can be used in conjunction. Below are the lists of

various technical issues as well as their relationships in a flow chart diagram.


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Emergency

Communications

Pre-Disaster (A)Post-Disaster (B)

Warning

Existing System

GPRS

Send MMS, SMS

NewArchitecture

Automated

Methodology for

Connection to Satellite

or Terrestrial Mobile

Warning Signal

Generation


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Format for

Broadcasting

Geographical Distribution of

Receivers

In remote areas existing

sophisticated network cannot

be guaranteed (GPRS,

Computer access)

Identification of the warning

signal and Alarm generation


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Issues under consideration for (A):

Physical/Network Components

Sensors Communication Link establishment under adverse weather

conditions

- typical network connections could become unreliableeasily

Network Architecture of the system Satellite coverage/ Terrestrial coverage Alarm format Channel configuration in Satellites/ mobiles Requirement

of emergency channel

Classification of warning depending on the receiver type Alarm activation


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Post_Disaster

(B)

Use of surviving

Base Stations

Collection of

Information

Detection of

Mobile by satellite

Integration of the

mobile to Ad Hoc

Network

Location

Identification


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Issues under consideration for (B):

Physical/Network Components

Architecture options Hierarchical Organization of Cellular Layers Organization of surviving network in a dynamic situation Mobile Ad Hoc networks Low Power Coding & Modulation Techniques Establishment of Basic Communication Links Establishment of High Speed Communication Links for

Management

Propagation Conditions under adverse conditions Cooperative Network Components (Mobile Stations)

Disaster Communication Assistance Concept Paper

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