Communicate When the World Goes Silent

The moment we hear of an earthquake or a flood, we try to contact our friends and relatives in the affected region. But are we able to reach them in most cases? The victims are cut off from the rest of the world and there is a virtual silence of misery and anxiety. This article shows how innovative methods can be implemented with existing technologies to put an end to this silence.

As the torrential rains lashed at the hill slopes of Uttarakhand, life came to a complete standstill in one of the biggest tourist centers of the country. Hundreds of lives were lost and property was damaged. Fear and panic spread as survivors unsuccessfully tried to contact their loved ones. In such situations, rescue and relief operations have been extremely difficult. Due to lack of authentic information and communication breakdown, the days following a disaster have never been devoid of panic and confusion.

To address this vital aspect of disaster management, namely, the establishment of a post-disaster communication system, the Japanese government, in collaboration with various technical institutes in India and Japan, has setup the DISANET (Information Network for Natural disaster Mitigation and Recovery) program. The main aim of this program is to develop a complete model that covers the various aspects of disaster management which include monitoring and modelling of weather and seismic activity, developing a robust communication network and execution of effective relief in a post-disaster situation.

The entire program was split into 4 major divisions, each of which were taken up by specific research groups from India and Japan. Among the four divisions, the development of sustainable communication architecture was undertaken by Professor Devendra Jalihal and Professor David Koilpillai from the Department of Electrical Engineering at IIT Madras along with Keio University, Japan. They have developed a very innovative and effective means of communication that can function as good as a cell-phone network even when all the existing communication systems fall prey to a disaster. It has all the important features required for a post-disaster communication setup which include less time for installation, greater accessibility, effective outreach and broadcast of authentic information. It does not require any custom built equipment which makes it readily available at any location within short time. Mobile phones are the most common means of communication and are heavily depended upon. Therefore this system makes use of the existing technologies available in mobile phones to provide an immediate and temporary communication means.

The physical setup includes an LTE (Long Term Evolution, commonly known as 4G) transmitter or antenna and other related equipment that are housed in a hoisted helium balloon for ensuring a large coverage area. The coverage is enhanced by using an FM broadcast system, which can convey information to victims regarding relief supplies, precautions and other rescue operation details. This information is broadcasted by an authentic source such as the district collector, over a certain frequency that the victims can tune to and get informed. The low bit rate digital data also called RDS can be used to broadcast centralized relief information in text format than can be read from the mobile. Generally, RDS is used by FM radio channels to display text such as the name of the song, channel and sometimes even the song lyrics on the screen of the audio setup. A similar text containing the helpline numbers, details of the whereabouts of relief materials,etc, can be broadcasted through RDS. Since FM-RDS is a feature available in a large number of modern GSM handsets, it offers the greatest outreach to the victims.

As mentioned above, FM broadcast is used to convey information from the authority at the control center to the victims. Similarly the victims also can send text messages, images and even short videos giving details of their location and condition to a certain number over the network. To facilitate this, WiFi and LTE (4G) technologies are used. Since WiFI has a short range, multiple antennas are set up in the surrounding areas and the main antenna is placed in the basket of the helium balloon. LTE has a large range of 20 to 30 km and therefore eliminates the need any intermediate towers. Hence it saves time and is the best means of communication when there is no possibility of setting up towers. Both WiFi and LTE technologies provide high bit-rate and can be used for streaming videos and images. for the benefit of those having mobile phones without any WiFi or 4G technology, there is also a GSM setup in the basket of the helium balloon that functions as a temporary tower. This acts as any other ordinary communication tower to transmit voice messages and calling. The details sent by the victims via the above mentioned modes, are are gathered by the call center authorities and provided to the rescue workers to carry out the relief operations. Also, the rescue troops can use this communication network to be in constant touch with each other and the main control unit.

Circuitry in the GSM Base Station
Circuitry in the GSM Base Station, Courtesy: Nithyanand N Rao

During any disaster, the main cause of communication breakdown is an increase in communication traffic over the usual communication networks. “Due to people trying to contact their loved ones in the affected areas, there is a large and sudden increase in the number of calls being made to a particular subscriber, leading to congestion and eventual breakdown” says Professor Jalihal. Therefore the DISANET communication system has introduced the ‘I am Alive’ feature to address this problem. A victim in the affected area sends a text message or an image to the call center which then updates his/her mobile number along with the message, date and time, on the internet as a searchable entity thus being accessible to everyone. In this way, the well being of a victim is conveyed to a large number of people at a time, thus avoiding excess traffic.

During the floods in Uttarakhand, the casualties’ details and information were not available even after 4 or 5 days following the disaster. This led to uncertainties in the whereabouts and well-being of victims. To overcome this limitation, the DISANET communication system makes use of the ‘person finder’ feature developed by Google. It uses the various attributes of a person to confirm his identity. The rescue operators take images or videos of the victims and send them to the main operation center. This data is presented to the world in standard formats known as PFIF (person finder information format). It consists of victim details displayed on dashboards. Initially, only the picture and a few details gathered by the rescue operators are available, but with time, people knowing the victim can add and update other details thus making the information wholesome. In other words, data can be refined and augmented with time.

This completes the entire framework of the DISANET communication system along with its features for providing effective and robust communication during disasters. The system was successfully tested on a small scale in IIT Madras in July 2014. According to Prof Jalihal, there are ongoing talks with the Chennai Police and Railways for implementing some of the features of this technology with a few modifications in heavily crowded areas during festive seasons in the city. It cannot be emphasized enough that malfunctioning of communication systems during crisis situations amplify the difficulties faced by the victims as well as the rescue troops. Hopefully, the establishment of such an efficient communication network will reduce the confusion during such times and in the process make the rescue work easier and more effective.

The DISANET Team, Credits: Prof. Devendra Jalihal

djDr. Devendra Jalihal is a Professor in the Department of Electrical Engineering at IIT Madras. He recieved his B.Tech from IIT Kharagpur in 1983 and then completed his Masters in engineering at McMaster University at Hamilton, Canada. In 1994 he joined the faculty at the department of Electrical Engineering. Dr Jalihal enjoys teaching the fundamentals of Electrical Engineering such as signals and systems and communication theory in undergraduate courses. His research interests include statistical signal processing, detection and estimation theory and Digital Communication.


tejTejdeep Reddy is a third year undergraduate student, pursuing his B.Tech in Naval Architecture and Ocean Engineering at IIT Madras. He is also actively involved in the development of an Autonomous Underwater Vehicle at the Center for Innovation, IIT Madras. To know more about this remarkable vehicle, go to this article and start savouring its story!

Featured Image Courtesy: Nithyanand N Rao