Investigating and presenting a robust and efficient routing protocol for military ad hoc wireless networks

Master's thesis in the field of telecommunication-system electrical engineering

Abstract

Investigation and presentation of a robust and efficient routing algorithm for military contingency wireless networks

Since the early 1980s, a new concept In the name of network-based defense, it has been created in the military. In order to achieve this concept, there is a need to have a military telecommunication network with a high capacity to be able to distribute information among the entities in the network. Wireless ad hoc networks have received much attention due to the fact that they do not need infrastructure. The most common use of contingency networks is military use. With the increasing development of network access technologies, we see the emergence of heterogeneous networks. In these networks, nodes use different technologies to communicate with each other. Contingency networks are usually associated with the problem of scalability and uncertainty. Most of the routing protocols proposed for these networks do not consider the requirements of heterogeneous networks. By considering the heterogeneity of nodes and taking advantage of it, the problem of scalability and reliability can be solved. In order to achieve this goal, it is suggested to use a hierarchical structure to take advantage of the advantages of heterogeneous networks. In this thesis, we will first introduce contingency networks, their history and applications. In the following, we introduce the types of routing protocols available. Then we introduce heterogeneous hierarchical networks to solve the problem of scalability and reliability. In the following, two new hierarchical routing protocols for heterogeneous military networks are introduced. These two new protocols are based on DSDV and AODV. In the proposed structure, it is assumed that the network nodes are heterogeneous in terms of radio transmission range and battery level. In this structure, all nodes are equipped with a short-range radio, but some of the nodes are also equipped with a long-range radio in addition to this radio. As a result, the nodes are divided into two categories and a two-tier hierarchical structure is formed. In these two protocols, at first, nodes are clustered in the first layer and the cluster head is selected for them. Next, the routing is done in the lower and upper layers. At the end, the proposed protocol is fully simulated with NS-2 simulator software. The efficiency of this protocol has been investigated in comparison with other routing protocols in different topologies. The problem of scalability, the effect of the number of clusters on this method, and the effect of the mobility of nodes on these methods have been investigated.

Key words: military contingency networks, hierarchical routing protocols, heterogeneous network, DSDV routing protocol.

1-1 Preface

Since the early 1980s, there has been a great growth There has been a rapid increase in the application of information technology [1] in the military forces and a new concept called network-based defense [2] has been defined and expanded. In order to achieve this concept, there is a need to have a military telecommunication network [3] with a high capacity to be able to distribute information among the entities in the network [1]. Also, in recent years, the use of telecommunication networks in military forces has been accompanied by major changes and significant improvements in the way a network is implemented and how its technologies are integrated in the army. Currently, having a military telecommunication network so that every soldier has the ability to access all the information available in the network is the highest priority of the military forces. On the other hand, with the development of long-range weapons, having long-range military telecommunication networks is a necessity.

A military telecommunication network allows each station to exchange information received through its sensors. By this means, the commander can easily increase the ability to identify his station by receiving station information, outside the range of his sensors, and this makes him more aware of his surroundings. As a result, military telecommunication networks give commanders the ability to fight in very large areas. Having such a network gives military forces a great advantage on the battlefield [2].According to this need, in this thesis we will have a comprehensive review on the routing algorithms of contingency telecommunication networks and finally we will introduce a heterogeneous contingency network suitable for military applications and according to the requirements of this network we will provide a suitable routing algorithm for it. Military wireless networks [4] experience many different conditions. The limitations and requirements of military networks are fundamentally different from commercial networks. The purpose of military networks is that communication should be established at any time and place on the battlefield, and this means that we must have a resistant telecommunication network [5] that can maintain communication everywhere [3], as well as high reliability [6], the ability to survive and long life [7] in critical situations [4].

The difference between military telecommunication networks and commercial networks (limitations and problems of military networks) [4]) is explained below:

All or most of its users are mobile [8] and the network topology is completely variable and dynamic.

Because of bad weather conditions and many natural obstacles, its links are completely unreliable, and the link quality and network capacity change.

Usually, the network should be able to be implemented quickly.

It has relatively little bandwidth.

The possibility of attacks to disrupt the network or signal interference is very high. Therefore, the network must be designed to be resistant.

There is a possibility of equipment being destroyed and lost by enemy forces.

Usually messages are sensitive to delay.

In terms of security, military networks face many limitations.

1-3 Contingency networks function in military systems

One ??technology that may meet the above network requirements and overcome its limitations and problems is mobile contingency networks [9] [1]. A MANET network is a collection of routers[10] equipped with wireless transmitters and receivers. These receivers and transmitters are free to move wherever they want and dynamically form an ad-hoc network - without any infrastructure or central user to command. The state of communication links at any moment of time is a function of various factors. As a result, the topology of the network changes rapidly [5].

The characteristics of mobile contingency networks [11], which make it suitable for use in military networks [6], are as follows:

It does not need infrastructure: it is not possible to create infrastructure in battlefields. The network must be capable of rapid implementation [2].

Having a dynamic (non-static) topology[12]: in military networks, users are mobile and the status of links is variable, as a result, the network topology is constantly changing.

Self-organized network [13]: It does not need a special center for management and command.

Self-ability It has treatment [14].

It has self-sustainability [15] (Military networks should have the possibility of fast reconstruction [16] and network recovery [17] [4].)

Having equal relationships among users

Considering these features, we understand that the contingency network is a suitable technology for military networks with mobility. are high [2]. Also, since there is a possibility of rebroadcasting [18] information in contingency networks, as a result, geographical limitations can be overcome and the coverage area can be expanded using successive rebroadcasts.