EECS455 Wireless Communication Systems

Introduction

On March 11, 2011, there was an extraordinary great east japan earthquake that resulted in a lot of adverse damage within the area. There was damage to the terrestrial network that made it quite difficult to contact the regions that were affected. The development of satellite communication has always presented the feature or option for resistance to disaster. During the march earthquake and other forms of disaster, the most precious form of communication that had to be adopted is satellite mobile phones. The National Institute of Information And Communication Technology (NCIT) was responsible for building a broadband satellite line between the agencies in charge of preventing the disasters and other teams that were dispatched to work together on the response activities in the regions affected (Suzuki et al, 2012). The response teams adopted the use of Wideband Internetworking Engineering Test and Demonstration Satellite (WINDS)

The national institute of information and communications technology is often in charge of researching and coming up with a resilient network against a disaster. This is achieved by the use of a satellite network and a wireless network. During this period, they were able to develop up to three different types of earth stations for the purpose of satellite communication. The three different earth stations were large–scale in-vehicle earth stations, fully automatic and transportable earth stations, and small mobile vehicle earth stations. Several experiments on disaster satellite communication were carried out by the use of the earth stations mentioned earlier (MAEDA, 2012). In one of the experiments, there was a connection of two wireless mesh networks by using a satellite link, whereas, on the other, there was transmission through HDTV image from moving earth stations. This research paper looks into details the three common types of earth stations that were developed to facilitate communication during such disasters and the communication experiments for disaster satellites by the use of the earth stations.

Fundamental Ideas

A : Support for the Disaster Response Activities Using Broadband Satellite Link

As previously stated, the great east Japan Earthquake caused a lot of damage to the eastern seaboard of Japan. There was damage to several terrestrial communication networks, including cell phones and telephones. This implied that it became quite challenging to communicate with individuals within the affected areas. During disaster instances like the great east japan earthquake, the relevant authorities and departments often organize a country-wide rescue effort (Takahashi et al, 2013). However, due to the disruption caused on the terrestrial networks, there were challenges in securing communications with the teams that were dispatched on the field with their command bases. The satellite mobile phone was always an essential means of communication but could not be sufficiently prepared within the time for the dispatched teams. The response teams and disaster prevention departments thus requested assistance from NICT to help them secure communication links through WINDS (Benyamina, Hafid & Gendreau, 2011).

WINDS is an engineering test satellite developed by both the NICT and the Japan Aerospace Exploration Agency (JAXA) and the NICT to generate high-speed satellite communication network technology. It is a geostationary satellite that was launched on the February 23, 2008. It uses Ka-band for the communication link. WINDS has a regenerative transponder that enables it to select uplink data rates from 1.5 Mbps, 6 Mbps,24 Mbps, 51 Mbps, and 155Mbps. The downlink data rate is at 155mbps only. On March 15, the NICT put up an earth station for WINDS at the Kesennuma fire station that was used as the command base center for the members of the response team that were dispatched from the fire department. The NICT was able to set up a successful broadband satellite communication link between the Tokyo Fire Department headquarters and Kesennuma. Communication devices such as a network camera, HDTV conference system, and PCs for various transfers of files were successfully connected to the earth station. On 2oth march, the Kesennuma earth station had been moved to Matsushima Airbase of the Japan self-defense forces (Akyildiz, Wang & Wang, 2005). Between that period to April 6, the NICT enabled a WINDS link between the Iruma Airbase and the Matsushima airbase. The connection of the internet was made possible from the Matsushima via Kashima. During the activities, some concerns such as the communication on the move, operability of the earth station, and the connected devices to the earth station. 

B : Resilient Network Using Wireless Communication

The occurrence of such a disaster has highlighted the essential role that developments in ICT plays. NICT carried out studies on the establishment of a robust ICT Network that cooperated with several companies and Tohoku University. The robust networks need to include a resilient photonic network, dependable satellite and wireless network, and anti-disaster platform for information distribution (Salem & Hubaux, 2006). The facilities have been set up at the Tohoku University Campus.

C : Earth Stations for a Resilient Network

By using WINDS, the NICT set up three types of earth stations to carry out a robust network experiment. In the development of the earth station, there was a reflection of the concern that came out at the time of support activities during the earthquake disaster.

Fully-Automatic Transportable Earth Station

During the occurrence of a disaster, it can be difficult for experts to maintain operations of satellite communication for all the setup earth stations. For this reason, the HICT developed a fully-automatic and mobile earth station that enables installation and easy operation by even individuals not considered experts (Jun & Sichitiu, 2003). 

Large-Scale In-Vehicle Earth Station

It was developed to operate as a communication hub that encompasses both the wireless terrestrial network and satellite communication when it is dispatched to the affected region. It is often installed in a large truck.

Small Mobile Vehicle Earth Station

It was developed to facilitate communication with the satellite while in motion such that the dispatched team at the scene can acquire the newest information on the disaster and thus modify its action plan after communicating with the dispatching body. The earth station has an interlock function that can disable transmission whenever the received signal becomes small (Draves, Padhye & Zill, 2004).

Disaster Satellite Communication Experiment

This involves two standard experiments designed by the NCIT through resilient facilities hosted at the Tohoku district. The developed earth stations were used as bases for carrying out the researches.

A : Experiment to Connect Two Wireless Mesh Networks

Wireless mesh networks of robust ICT facilities have been set up at two different campuses located almost 5 km apart (Hamilton & Anderson, 2002). An optical fiber network facilitates the connection of the two wireless networks. It was assumed that the fiber network was damaged during the pandemic. A fully automatic and transportable earth station was set up at the venues and connected to the wireless mesh network. The setup enabled the usage of internet applications from the connected device wireless network in the region affected by the disaster (Li et al, 2004).

B : HDTV Transmission Experiment from Moving Earth Station

The experiment assumed that the disaster occurred, and a small mobile vehicle earth station was dispatched for rescue operations. The occurrences all through the way were captured and transmitted via the satellite link. The experiment also demonstrated a voice conference system of communication between individuals at the earth station and the receiver (Lee, Ku & Ahn, 2010). The communication was, however, at times disrupted by objects like buildings and trees and appeared to follow a given communication protocol.

Conclusion

The occurrence of the disaster underlined the importance of developing appropriate communication systems that can be disrupted when needed most. They had to develop three different types of earth stations for robust ICT facilities. Various experiments involving disaster satellite communications were carried out as described. There is a need to improve the equipment for such detailed experiments. More experiment plans will help describe the connecting link between two wireless mesh networks by the use two satellite links with Ku-band and Ka-band. The technologies developed to help promote communications during the great east Japan Earthquake have been constantly used during similar and subsequent disasters. Most disasters are often catastrophic and result in the destruction of various infrastructures, including communication lines. During response activities, communication is often key for the response teams to efficiently carry out their activities. Whenever the disaster destroys typical and terrestrial communication methods, more technological advancements and setups are often called to aid communication. WINDS have been used to relay the internet to several business settings and homes in japan via Ka-Band signals. The technology followed a series of experiments and tests that enabled it to be used by future communication satellites in Japan. NICT and JAXA mainly operated the technology.

References

• Suzuki, R., Takahashi, T., Takizawa, O., Akioka, M. and Kondo, Y., 2012. Survivability application demonstrations via wideband internetworking engineering test and demonstration satellite “KIZUNA”(WINDS). Acta Astronautica, 73, pp.206-211.
• MAEDA, T., 2002. Wideband InterNetworking Engineering Test and Demonstration Satellite. In Of 2002 Joint Conference on Satellite Communications, Daejeon, Korea, October, 2002(pp. 48-53).
• Takahashi, T., Jeong, B., Okawa, M., Akaishi, A., Asai, T., Katayama, N., Akioka, M., Yoshimura, N., Toyoshima, M., Miura, R. and Kadowaki, N., 2013, June. Disaster satellite communication experiments using winds and wireless mesh network. In 2013 16th International Symposium on Wireless Personal Multimedia Communications (WPMC)(pp. 1-4). IEEE.
• Benyamina, D., Hafid, A. and Gendreau, M., 2011. Wireless mesh networks design—A survey. IEEE Communications surveys & tutorials, 14(2), pp.299-310.
• Akyildiz, I.F., Wang, X. and Wang, W., 2005. Wireless mesh networks: a survey. Computer networks, 47(4), pp.445-487.
• Salem, N.B. and Hubaux, J.P., 2006. Securing wireless mesh networks. IEEE Wireless Communications, 13(2), pp.50-55.
• Jun, J. and Sichitiu, M.L., 2003. The nominal capacity of wireless mesh networks. IEEE wireless communications, 10(5), pp.8-14.
• Draves, R., Padhye, J. and Zill, B., 2004, September. Routing in multi-radio, multi-hop wireless mesh networks. In Proceedings of the 10th annual international conference on Mobile computing and networking(pp. 114-128).
• Li, H.B., Sato, M., Miura, A., Taira, S. and Wakana, H., 2004, September. Ku-band helicopter satellite communications for on scene disaster Information transmission. In 2004 IEEE 15th International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE Cat. No. 04TH8754)(Vol. 4, pp. 2792-2796). IEEE.
• Hamilton, J.B. and Anderson, P.S., 2002. Satellite communications in disaster management: selected Canadian systems. Space communications, 18(3, 4), pp.187-193.
• Lee, Y.M., Ku, B.J. and Ahn, D.S., 2010, November. A satellite core network system for emergency management and disaster recovery. In 2010 International conference on information and communication technology convergence (ICTC)(pp. 549-552). IEEE.
• Takahashi, T., Jeong, B., Okawa, M., Akaishi, A., Asai, T., Katayama, N., Akioka, M., Yoshimura, N., Toyoshima, M., Miura, R. and Kadowaki, N., 2013, June. Disaster satellite communication experiments using winds and wireless mesh network. In 2013 16th International Symposium on Wireless Personal Multimedia Communications (WPMC)(pp. 1-4). IEEE.