Performance evaluation of mobile ad hoc network based communications for future mobile tele-emergency system

The needs to provide medical services in remote areas have motivated researchers to develop tele-emergency systems. The tele-emergency is defined as the delivery of health care and sharing of medical knowledge over a distance using the telecommunication applications in emergency situations. In most cases, it is very likely that very remote areas and disaster struck areas lack telecommunication infrastructure. Tele-emergency system operating in such areas must have advanced wireless technology supporting it. The previous researchers on telemedicine system totally depended on WLAN transmission and satellite communications only for patient to doctor consultation and inter hospital services. In disastrous conditions such as earthquakes, floods and natural calamities the telecommunication infrastructure deteriorates then an emergency ad hoc setup should be installed to save many valuable lives. The satellite communications help for some extent in communication, but in rural areas those base station setup is not possible and very expensive for implementation. Our present work is based on mobile ad hoc network, which is the latest technology in form with less implementation costs rather than satellite communication. The mobile ad hoc network is combined with the mobile IP and MIPV6 to form the architecture of the proposed mobile tele-emergency system. Apart from the other existing models of the telemedicine systems, the proposed architecture has more advantages in terms of infrastructure costs, easily accessible to the users and more reliable for transmission. The tele-emergency system requires data, voice and video transmission in its network. Our evaluation is based on simulation of the various ITU-T standard CODECs of VoIP, video over MANET using discrete event simulator NS-2. In our simulation results we observed that ITU-T G723.1 works well in the MANET environment bettering from the other CODECs for VoIP in fixed and mobility environments, in fixed network for packet delivery fraction it showed a varying performance of 84.3% to 40% for increasing number of connections from 4 to 20. For average end to end delay G723.A recorded a more stable delay rate in all connections ranging from 0.22 to 0.58 second. G723.A also worked well for normalized routing load, the transmission quality of the CODEC is also good for more number of connections. From the simulation of video CODEC performance evaluation, it is observed that H.263 works well in random small scale environment and also in multiple video flow of 57.6kbps speed video transmission. In MANET routing, the mobile wireless nodes suffer signal interference due to the existence of the other active nodes. In an emergency scenario, there should be a method to route the traffic from and to the gateway without presenting extra load to the area, while maintaining the quality of the links from the gateway to the destinations within an acceptable level. We proposed the gateway routing optimization using genetic algorithm, the result of our simulation in gateway routing of mobile nodes over MANET shows that the best alternative routes given by GA can replace the routing given by the conventional MANET routing protocol.