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Mobile Ad hoc NETworks (MANETs) are an important part of wireless communications and the increasing use of mobile devices is confirming that. MANETs can be of great value in Emergency Response situations where communication between mobile deployed units is critical and wired or wireless infrastructures may not be present or functional. In emergency scenarios, multimedia communication is very important for decision making and situation assessment. This requires up-to-date (on-line) information feed on the situation, including voice and video from the affected zone. However, MANETs do not seem to efficiently support multimedia applications, and this is quite evident in video transmission. One way to remedy this is to use more (wireless) interfaces per mobile node and consequently more communication channels. In this work, we perform an analytical study on the use of multiple interfaces and multiple channels (MIMC) in video transmission with respect to the requirements of Emergency Response Ad hoc Networks. More specifically, we examine and present the impact of using MIMC on MANETs during video transmission applications, we evaluate the performance of three basic routing protocols in MANETs, and we propose a channel selection mechanism in MANET nodes with MIMC for enhanced video transmission. In addition, we evaluate video transmission streams with rate adaptation and present comparative results. The proposed mechanism is evaluated using the ns-2 network simulator and the simulations are performed for a variety of topologies. Simulation results show that the different routing protocols respond differently when MIMC is introduced. The Ad hoc On-Demand Multipath Distance Vector and (especially) the Ad hoc On-Demand Distance Vector routing protocols benefit significantly, while the Destination Sequenced Distance Vector shows fewer improvements. The proposed mechanism is shown to be beneficial for transmitting video streams and enhances the network's ability to accommodate more streams and reduce packet delay.

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Vehicular Ad Hoc Networks (VANETs) are considered as a special case of mobile Ad Hoc Networks (MANETs) and are recently gaining a great attention from the research community. The need for improved road safety, traffic efficiency and direct communication along with the great complexity in routing, makes VANETs a highly challenging field. Routing in VANETs has to adapt to special characteristics such as high speed and road pattern movement as well as high linkage break probability. In this work, the authors show that traditional MANET routing protocols cannot efficiently handle the challenges in a VANET environment and thus need further modifications. For this reason, they propose and implement an enhancement mechanism, applied to the GPSR routing protocol that adapts to the needs of a VANET. The proposed mechanism's performance is evaluated through simulation sets for urban and highway scenarios and compared to the performance of the most common MANET routing protocols adopted in VANETs. The proposed enhancement is shown to be considerably beneficial and it significantly outperforms the rest of the tested routing protocols for almost every topology setting.