Flexibility-Enhanced HTS System for Disaster Management: Responding to Communication Demand Explosion in a Disaster

Natural disaster interrupts essential services due to the facility damage and lack of power supply. Especially, significant communication outages occurs in a wide area for hierarchical network such as cellular communication system in case core nodes are damaged or congested. In order to provide alternative communication ability, high throughput satellite (HTS) is one of the ideal candidates for disaster management because it provides operative communication for a wide area regardless of the availability of regular terrestrial infrastructures. However, conventional HTS relays data with predetermined beam bandwidth and connection, it is inefficient when the communication demand explodes in a disaster area. Therefore, this paper proposes novel frequency allocation technique with flexibility-enhanced HTS system for disaster management to respond to communication demand explosion. While related research works consider user-link resource allocation, this paper focuses on how to control feeder-link and user-link bandwidths in case that the both links can be assigned at continuous frequency such as Ka-band. Furthermore, our proposal addresses resilient satellite network by selecting optimum gateway based on the traffic demand at neighboring user-link beams. The effectiveness of our proposal is verified through simulation results.

I. Introduction

After the occurrence of natural disaster, communication recovery is important to any phases of disaster management. The first response, rescue team and command centers require quick deployed network to coordinate relief efforts across wide areas even though the regular terrestrial networks are damaged. The recovery phase, communication is required to support higher speed for more sophisticated applications such as virtual private network (VPN), emails and internet browsing. Especially, lessons from Great Tohoku Earthquake and Tsunami in Japan, communication outages occurred in wide area for cellular network even though the base stations were not damaged because the core networks were congested by traffic explosion. Specifically, cellular operator experienced fifty times or more of call attempt than usual and satellite operator allocated 500MHz of additional bandwidth to disaster area [1], [2]. Furthermore, a lot of base stations stopped their functions due to the lack of power supply [2].