Hybrid Wireless Mesh Network with Application to Emergency Scenarios Raheleh B. Dilmaghani University of California, San Diego, La Jolla, USA rdilmaghani@ucsd.edu Ramesh R. Rao University of California, San Diego, La Jolla, USA rrao@ucsd.edu Abstract— Establishing and accessing a reliable communication infrastructure at crisis site is a challenging research problem. Failure in communication infrastructure and information exchange impedes the early response efforts resulting in huge loss of lives and economical impacts. In this paper, we present the results taken over the wireless mesh network that had been deployed to provide first responders with an infrastructure for local communication on campus during the drill. Additionally the network was connected to the outside world through a wired backhaul. This infrastructure is quickly deployable, easily configurable and interoperable in a heterogeneous environment with minimum interdependencies. We present the measurements taken directly over the network by capturing operational network traces to evaluate network performance and identify the source(s) of bottleneck to improve performance and network resource usage for future deployments. Index Terms— Mesh network, Emergency communication deployment, Real scenario measurements, Field data and Performance evaluation I. INTRODUCTION This work studies different key factors in designing a robust communication infrastructure with applications for emergency response situations. A robust communication infrastructure must consistently detect and dynamically adapt to the changing network circumstances including different devices using various technologies joining and leaving the network. Additionally, the network should support distributed command and control systems to enable different first responders exchange information and collaborate. In most disaster scenarios such as 9/11, different organizations have not been able to communicate with each other [8] [20]. This is because either the network becomes unavailable at some point in time, or different devices are not able to cooperate. Considering the scale and frequency of the recent disasters such as World Trade Center and Hurricane Katrina, there has been more attention paid to the continuous availability of a robust communication infrastructure to assure the best and fastest service. Design of such system affects emergency response and recovery in addition to planning. Also, considering the different ways the nation is affected by each one of these large scale disasters shows the importance of developing research in such wide multi-disciplinary research areas. This requires electrical and computer engineers to work closely with social scientists, structural engineers, and researchers from many other disciplines to identify the vulnerabilities in the proposed communication infrastructure and improve system reliability. Based on National Science and Technology Council Committee of environmental and Natural Resources, “a sustained emphasis on risk mitigation and public/private partnerships is essential throughout all aspects and at all levels of the community” [23]. Some of the frequently observed, serious outcomes of disasters are loss of lives, health issues, social effects such as looting, or economic pressures such as price gouging, more specifically gas price and loss of the tourism industry [21] [22]. From technology and business perspectives, when there is a power failure, most markets are affected with an inevitable impact on the economy of the country as reported aftermath of blackout incidents recently. There are many references about the lack of communication between Police and Fire department at the 9/11 disaster. The Fire department did not hear warnings issued by the Police department asking for evacuation of all people in the area of the second building [5]. This incident confirms the necessity for a technology that is able to work with heterogeneous devices to send and receive messages across different systems. A robust communication infrastructure provides connectivity in a heterogeneous environment. We address the overall communication problem with existing infrastructures by deploying a mesh network to resolve issues such as interdependency, unreliability, and interoperability. Some of these shortcomings have been the main cause of existing communication infrastructure failure at many incidents [2]. This is why the problem of designing a robust communication technology is becoming crucial. 52 JOURNAL OF SOFTWARE, VOL. 3, NO. 2, FEBRUARY 2008 © 2008 ACADEMY PUBLISHER