Research On The Key Technologies In Tactical MANET

Tactical Mobile Ad Hoc Networks are the applications of Mobile Ad Hoc Networks in battlefield environment. It is the wireless network that has no infrastructure for supporting and with the properties of self-organizing and self-reconstructing and multi-hop. The configuration and channel condition and service model is vary dynamically with node's moving in the networks.This paper sets the background of typical military affairs applications and aims at constructing the region mobile tactical communication networks. It focuses on the two research aspects of wireless transmission and scalability of the tactical MANET. We want to constitute the basic theory effectively of wireless transmission and key technology to enlarge the capacity of tactical mobile Ad Hoc networks. We wish to investigate the new method to extend the scalability of Ad Hoc networks using new routing protocol also. The main work and results of this paper are as follows:1. A new multi-polarization array antenna was developed and a new method to improve the system transmission capacity of tactics Ad Hoc networks using affixation polarization of electromagnetic wave in multi-path environment was put forward. We researched the boosting the channel capacity of tactics MANET using multi-polarization technology by theory analysis, practice measure and computer simulation.2. We invented an imitating biology antenna of endowing with shape. The analysis model of the antenna was founded. In this chapter, we put forward an electromagnetic wave transmitting model of mobile nodes in multi-path environment based on the antenna. With the shape memory alloy (SMA), such as Ti-Ni alloy, the antenna has the function of shape memory effect (SME). According to the per-design scheme, the antenna shows the different shapes in different temperature, and so it has functions of endowing with shape. This means that we can change the antenna's wave sheaf and direction figures by changing its geometry structure. By sub-area shelter testing, analysis results show that the antenna has the characteristic of diversity combining. Comparing with reference antenna, the antenna can get extra gain of 30dB that is very important to wireless communication system for increasing of SNR.3. In the paper of the sixth chapter, we proposed the Node Location Routing Protocol (NLRP) and funded the overhead function and relationship between routing overhead and location update threshold. NLRP is an equilibrium scheme between the table-driven routing (proactive routing) and reaction routing. All of the nodes make use of location information and got other node's location and mobility. The location broadcasting brings location update overhead (LUO) in proactive routing and routing finding bring routing search overhead (RSO). The more the frequencies of location update broadcasting, the more the LUO. Otherwise, if the time interval is greater, the frequency will be smaller, and then the LUO is smaller. Nodes must search for the bigger area and increasing RSO. We should find a new scheme that keeps the total overhead to be least.To balance the two overhead, the choice rule of node's location broadcasting frequency threshold must satisfy the follow conditions:when the node's location information is so new enough that the destination node's location can be determined, keeping LUO small sufficiently. In other words, there must be the best node's location broadcasting frequency threshold to keep the sum of RSO and LUO the smallest. To search the optimum threshold, we founded the mathematics model of routing request and node mobile randomly. The results of computer simulation show that all of the performances of NLRP are better than other conventional routing protocols.4. In the theory analysis of NLRP protocol routing overhead, we proposed that the time-based location update threshold be inversely proportional to the mean squared speed. Under this condition, we proved that the whole overhead is a convex function of the threshold and derived the optimal solution. We proposed realistic models for route requests and node mobility and formulated the update overhead using the expected number of location update per route request, and the search overhead using the expected search scope, which is a function of the interval between the route request and the last location update.The NLRP protocol has the following advantages. First, the use of route search scope estimation makes the routing a location operation, and hence solves the problem of reactive protocols that require a global route search operation, while retaining the high route discovery performance; Second, by broadcasting its own location information at a low frequency, each node significantly reduces the update as compared to the proactive model that broadcast the routing table; Third, the proposed protocol is capable of setting optimal thresholds if relevant parameters are either known or estimable; Further, the optimality of the proposed protocol holds for any route request distribution, hence making it widely applicable.