Research On Routing Protocols For Mobile Ad Hoc Networks Under Circumstances Of Field Communications

Field communication is one of the most primary application backgrounds for mobile ad hoc networks, which need stronger survivability, less overhead, lower delay, anti-jamming and robust security. So, under this circumstance, the thsis has researched on energy balance, congestion control, anti-jamming and secure routing for ad hoc networking, also some novel improved algorithms and schemes have been brought forward. Finally, detailed simulations and analyses have been done to verify the validity of these algorithms.The application requests for the performance of ad hoc networking in field communication mainly represent as packet delivery ratio, overhead, end-to-end delay and throughput, etc. But there are so many factors influencing its performance that the considerations should be from the application layer to the physical one, and the routing is more significant. So, firstly the thesis has analyzed and evaluated many current routing protocols that are applied to the field ad hoc networks, and then proposed some better choices and designments. In addition, the performance maybe further deteriorated due to the interference and intended attacks in battlefield, so the basic solution to promote the networking performance is to use more advanced routings and improve corresponding strategies simultaneously, which is the orientation and the emphasis of my research.Zone routing protocol (ZRP), as the hybrid of proactive and reactive routing, is targeted for scalable networks, so it is greatly fit for military ad hoc networking. Based on this protocol, the thesis has promoted two novel algorithms for the congestion control and energy equilibriums separately. One is modified zone routing (MZRP) based on nodes position and networking density, and the other is energy-awareness zone routing (EAZRP). The former utilizes the information of locations provided by GPS to reduce the frenquency of corresponding interrupts during neighbor maintenance. Also, the depth of the search when traversalling the routing records is shortened according to the density. These two adjustments can reduce the overhead and propagation delay effectively. The latter, EAZRP, introduces multi-paths into zone routing and distributes the traffic over many available optimum paths during packets routing. So in a situation that the total amount of the business does not change, more nodes participate in the delivering, which can obviously decrease the variance of energy consumption among all terminals while other performance indexes have not got any damage. The decrease of consumption variance makes the nodal working life become more average, so the life-time of entire ad hoc networking is improved greatly.The current mobile ad hoc networks adopt the omnidirectional antenna to transmit signals, and the performance is very poor because of ISI and the multi-access interference. Directional beams have limited bandwidth, which can not only reduce the mutual interference among the propagated signals, but also increase the spatial-reuse of the system. Moreover, under the same transmission power condition, directional antennas can get a further propagation distance than omnidirectional ones. These characters can promote the network capacity and anti-jamming performance effectively. Different from the typical DOA algorithms, we adjust the directivity of beams with the aid of position information provided by localizers, which can simplify the realizable complexity. Based on this, SDBA, a novel scheme for anti-jamming ad hoc networks using directional beams has been put forward. It was designed as a middle-ware that could transceive unicast data packets and/or selected control ones with directional antennas. This could greatly improve the ad hoc routing performance and link stabilities, thus the anti-jamming capability of battlefield networking was promoted.Considering the routing securities, current algorithms are mostly ways based on that information is encrypted, which is quite complicated and difficult to realize. By means of detailed evaluations of the attacks on four typical ad hoc routing protocols, we have found that the proactive and reactive routing are very sensitive to the illusive route-table and rushing attack respectively. Accordingly, a position beased secure routing schedule for the proactive has been proposed in the thesis. It estimated the reliability of received route-table making use of positions information, so the diffuseness of hostile packets was confined to a limited area, thus the influence of malicious nodes was severely restrained.