Tactical Networks Research Articles

Ad Hoc Mobile Wireless Networks Routing Protocols – A Review

Mobile ad hoc networks(MANET) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self organize into arbitrary and temporary ad-hoc network topologies, allowing people and devices to seamlessly internet work in areas with no preexisting communication infrastructure e.g., disaster recovery environments. An ad-hoc network is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad-hoc paradigm. Recently the introduction of new technologies such as Bluetooth, IEEE 802.11 and hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent revolutions have been generating a renewed and growing interest in the research and development of MANET. To facilitate communication within the network a routing protocol is used to discover routes between nodes. The goal of the routing protocol is to have an efficient route establishment between a pair of nodes, so that messages can be delivered in a timely manner. Bandwidth and power constraints are the important factors to be considered in current wireless network because multi-hop ad-hoc wireless relies on each node in the network to act as a router and packet forwarder. This dependency places bandwidth, power computation demands on mobile host to be taken into account while choosing the protocol. Routing protocols used in wired network cannot be used for mobile ad-hoc networks because of node mobility. The ad-hoc routing protocols are divided into two classes: table driven and demand based. This paper reviews and discusses routing protocol belonging to each category.

Key Challenges of Military Tactical Networking and the Elusive Promise of MANET Technology

Mobile ad hoc networks (MANETs) are considered by many as fundamental to realizing the global information grid (GIG) and the vision of network-centric warfare. Indeed, a fully realized MANET would be powerful in enabling highly mobile, highly responsive, and quickly deployable tactical forces. However, significant technical challenges remain before this realization is viable. Addressing these deficiencies is a significant task that will require the invention and adoption of new technology. The goal of this article is not to declare these capabilities impossible to achieve. Rather, it is to manage the expectation of the capabilities achievable in the foreseeable future through edification on the technical difficulties standing between current technology and the desired capabilities. This article provides an overview of the military MANET problem space, describing the ideal military MANET solution. Several deficiencies are highlighted that exist between MANET technologies and the desired capability. Identified technical issues include system-level architecture, routing (both interior and exterior), management, security, and medium access control (MAC), with an emphasis on the former two areas

Military multi-hop routing protocol

Military tactical network is one of the most important applications of ad hoc network. Currently the existing routing protocols are put forward based on the simple and universal network model which has the ability of multi-hop routing but cannot work efficiently in the special military applications. The narrow bandwidth and limited energy of the wireless network make general routing protocols seem to be more redundant. In order to satisfy military needs properly, this letter makes a detailed analysis of physical nodes and traffic distribution in military network, uses cross-layer design concept for reference, combines traffic characteristic of application layer with routing protocol design. It categorized routing problem as crucial routes and non-crucial routes which adopted separate maintenance methods. It not only realizes basic transmission function but also works efficiently. It is quite fit for military application.

The use of service level agreements in tactical military coalition force networks

Tactical military coalition force IP networks will have to offer quality of service. Service level agreements and service level specifications are important elements of the QoS architecture in civilian networks. However, SLAs/SLSs in military coalition networks should not be applied in the same fashion as in a commercial network. Our contribution is to identify the useful role SLAs/SLSs can play in network engineering and QoS management of tactical coalition force networks. The SLS definition needs to be more detailed than for a commercial SLS, and its monitoring must be performed on a finer timescale than in comparable commercial networks. The security architecture of military coalition networks may also restrict the monitoring and SLA management. Finally, we sketch a measurement-based approach showing how SLSs can be used in tactical military coalition force networks to support both call admission control and network engineering. Parts of this analysis include a discussion of SLSs and the proposed NATO standards for tactical communications network.

Partitioning QoS management for secure tactical wireless ad hoc networks

Addressing quality of service in military wireless ad hoc communication networks involves unique challenges due to imposed tactical requirements and,conditions, such as heterogeneous traffic with stringent-real-time and survivability requirements, mobile wireless nodes in hostile environments, and limited spectrum availability. Encryption adds another layer of complexity because of the partitioning of the network into plain text (unencrypted) and cipher text (encrypted) parts that, by definition, cannot communicate QoS information to one another. A typical communication shelter is composed of unencrypted LANs connected to a packet-encrypted backbone network. This article presents a partitioned QoS approach, focusing on QoS management at the unencrypted LAN that complements QoS management done at the encrypted backbone. Some of the unencrypted LAN QoS techniques being considered for the Warfighter Information Network-Tactical (the future Army tactical backbone network) are outlined.

On the design and management of heterogeneous networks: a predictability-based perspective

While great strides have been made in the design and deployment of commercial networks over the past two decades, relatively little progress has been made toward the realization of large-scale tactical military networks. The primary reasons for this disparity include the fact that commercial telecommunication networks are predominantly wired, relatively stable infrastructures, whereas tactical networks consist largely of wireless mobile nodes with unique operating characteristics in hostile environments. Wireless networks must cope with dynamic link conditions not present in wired infrastructures, which place a heavy burden on quality of service management solutions. Managing QoS in the face of constantly changing operating conditions demands dynamic management approaches that span multiple layers in the protocol stack. Such cross-layer design approaches have recently received attention in the context of cellular and mobile ad hoc networks. However, there are still a wide range of opinions and definitions about what exactly CLD entails, and there is no fundamental guidance concerning how to apply CLD techniques in various environments. In this article we introduce the notion of network predictability and describe its relationship to achievable QoS. This relationship is used to propose a framework for CLD that can be used to guide development efforts and direct investment decisions for future military networks. The framework also contains the notion of a crosslayer coherence length, which determines the protocol layers across which the highest degree of coupling, or correlation, should be present in order to realize the greatest possible gains in achievable QoS.

OLSR performance measurement in a military mobile ad hoc network

Wireless ad hoc networks are autonomous, self-configurating and adaptive. Thus, such networks are excellent candidates for military tactical networks, where their ability to be operational rapidly and without any centralized entity is essential. As radio coverage is usually limited, multihop routing is often needed; this is achieved by an ad hoc routing protocol supporting nodes mobility. In this paper, we present performance measurements of the Optimized Link State Routing (OLSR) routing protocol, having the status of IETF RFC. The measurements are performed at CELAR site on a platform representative of military scenarios in urban areas. This platform consists of ten routers, eight PDAs and laptops using a IEEE 802.11b radio interface and implementing OLSR v7. Some nodes are mobile within vehicles. The emphasis of the measurements is on the performance of the network (route repair, network convergence speed, user traffic performance) in presence of this mobility.

Evaluating the Performability of Tactical Communications Networks

Tactical communications networks are multihop wireless networks in which switches and endpoints are mobile nodes. In a tactical environment, system performance degrades when switching nodes and/or communication links fail to operate. Fast algorithms for performance analysis are desirable for optimizing the network in a timely fashion. Further, tactical networks commonly use preemptive priorities to achieve low blocking probabilities for high-priority calls when the loss of equipment in the battlefield is not trivial. This paper discusses three measures and analytical algorithms for the performability evaluation of a two-tier tactical communications network where preemptive priority service discipline is employed and traffic is divided into multiple classes to provide multiple grades of service. Each class of traffic has its distinct characteristics, such as average call-arrival rate, average call-holding time, and service priority. The three performability measures are devised to evaluate the impact of nodes/links failures on system performance. Experiments show that the preemption does provide robust service for higher priority traffic. The techniques for performability evaluation presented in this paper may also be useful in other rapidly deployable networks, where mobility, communication efficiency, and computational complexity for adapting the network to unpredictable environments are of significant concern.

Integrated service network design for a cross-docking supply chain network

This paper considers an integrated service network design problem for a given set of freight demands that is concerned with integration of locating cross-docking (CD) centers and allocating vehicles for the associated direct (transportation) services from origin node to a CD center or from a CD center to the destination node. For the vehicle allocation, direct services (sub-routes) should be determined for the given freight demands, and then the vehicle allocation has to be made in consideration of routing for the associated direct service fulfillment subject to vehicle capacity and service time restriction. The problem is modeled as a path-based formulation for which a tabu-search-based solution algorithm is proposed. To guarantee the performance of the proposed solution algorithm, strong valid inequalities are derived based on the polyhedral characteristics of the problem domain and an efficient separation heuristic is derived for identifying any violated valid inequalities. Computational experiments are performed to test the performance of the proposed solution algorithm and also that of a valid-inequality separation algorithm, which finds that the solution algorithm works quite well and the separation algorithm provides strengthened lower bounds. Its immediate application may be made to strategic (integrated) service network designs and to tactical service network planning for the CD network.

Mobile ad hoc networking: imperatives and challenges

Mobile ad hoc networks (MANETs) represent complex distributed systems that comprise wireless mobile nodes that can freely and dynamically self-organize into arbitrary and temporary, “ad-hoc” network topologies, allowing people and devices to seamlessly internetwork in areas with no pre-existing communication infrastructure, e.g., disaster recovery environments. Ad hoc networking concept is not a new one, having been around in various forms for over 20 years. Traditionally, tactical networks have been the only communication networking application that followed the ad hoc paradigm. Recently, the introduction of new technologies such as the Bluetooth, IEEE 802.11 and Hyperlan are helping enable eventual commercial MANET deployments outside the military domain. These recent evolutions have been generating a renewed and growing interest in the research and development of MANET. This paper attempts to provide a comprehensive overview of this dynamic field. It first explains the important role that mobile ad hoc networks play in the evolution of future wireless technologies. Then, it reviews the latest research activities in these areas, including a summary of MANET’s characteristics, capabilities, applications, and design constraints. The paper concludes by presenting a set of challenges and problems requiring further research in the future.

Some Key Technologies in Artificial Intelligence for Defence Applications

With the advent of various sensor technologies and tactical communication networks, the earlier problem of ‘fog of war’ has been transformed into one of information overload. In this paper we review certain key technologies that will enable commanders to effectively deal with the incoming data in order to make optimal and timely decisions. These technologies range from broad areas like expert systems, natural language processing and decision support systems to more focussed areas like neural networks, genetic algorithms and multi-sensor data fusion algorithms. An ability to deploy the correct mix of these technologies will be the key to success in futuristic digital battlefields.

Scalability in global mobile information systems (GloMo): issues, evaluation methodology and experiences

The GloMo (Global Mobile Information Systems) project1 has focused on developing new wireless ad hoc networking technologies. These new technologies rely on a broad and varied set of techniques to help cope with the problems inherent in the wireless environment. One of the most critical design elements of all the various technologies is their applicability in large scale deployments. The main objective of our work is to develop and implement a simulation methodology to help evaluate the scalability of these new ad hoc networking technologies and gain some insight into the various aspects of ad hoc network performance scalability issues. To achieve that we have developed a scalability performance evaluation framework and plan, that spans all the various dimensions of scalability: size (number of nodes and density), traffic, operational environment (i.e. propagation models, terrain etc.), mobility. For demonstration purposes we have applied this process on a representative integrated protocol suite designed to provide communication services in mobile ad hoc wireless networks. The corresponding results of the two most critical aspects of scalability properties in tactical networks (i.e. network initialization time and traffic scalability) are also presented here, and demonstrate that a very extensive evaluation of the corresponding scalability metrics under a combination of the various scalability dimensions defined in this paper, is necessary in order to provide an in-depth analysis of the scalability properties in wireless mobile ad hoc networking environments.

A comparison of channel scanning schemes for distributed formation and reconfiguration

A packet radio network (for example, wireless LAN, mobile tactical network) consists of a number of nodes, each equipped with a transceiver, exchanging data packets via radio channels. In this paper we identify and discuss issues related to the process of forming a network in an automatic and distributed manner. During network initialisation and reconfiguration, the time to complete the network formation process is an important performance parameter. We define two measures which can be used for computing the network formation time. Also, we present a comparative evaluation of two channel-scanning schemes (synchronous and asynchronous) for multiple frequency operations using a broadcast access scheme based on CSMA. Our study of networks with different spatial distributions of nodes shows that the asynchronous scanning scheme performs better when the ratio of the number of 1-hop neighbours to the number of available channels is high. Its performance is somewhat worse than that of the synchronous scheme for sparse networks. It is also sensitive to changes in the channel dwell time of the receivers, compared with the synchronous case.

Tactical Military Communication Networks of the Future .

Military communication has the added dimension of mobility and bandwidth conservation. The paper deals with the necessity of advanced concepts of communicating images. data and fax in addition to voice as dictated by the command and control requirements. The Integrated services digital network as applied to tactical network of the future is presented. The topics of routing, encryption, mobile access, digital links are briefly covered. The importance of standards of CCITT and contemporary techniques like B-ISDN, cellular radios are discussed. The relevance of network management and its main features are brought out.

An FDDI network for tactical applications

A fiber-optic tactical local area network (FOTLAN), based on the fiber distributed data interface (FDDI), that supports data packet traffic simultaneously with synchronous traffic is described. The current US Army LAN implementation is examined, and its limitations are highlighted. An overview of a migration path from the current LAN to the ATCCS (Army tactical command and control system) objective system using FOTLAN is presented to demonstrate how such a network can evolve. >

An Analysis of a Distributed Switching Network with Integrated Voice and Data in Support of Command and Control

This paper explores the potential for increased transmission efficiency of military tactical command and control data links through voice/data integration. The relationship between voice and data communications as they are employed in support of Military Command is examined, and operational advantages to the integration of voice and data are enumerated. A message processing/handling paradigm of the command and control process is introduced. Past analyses are extended to include tactical data links, and an evaluation of the relative advantages of various degrees of voice/data integration over tactical data links and networks is presented. It is shown that it is generally more efficient for voice and data traffic to share voice-equivalent channels on a statistical contention basis than for voice and data to operate over separate dedicated data link voice-equivalent channels. Important exceptions to this rule are duly noted. Finally a hybrid scheme, where a thin-line capability is reserved for a special class of data and/or voice and where the remainder supports an integrated voice-data operation, is described and analyzed. This scheme is shown to be practical and to result in little loss of efficiency over the more complete voice/data integration analyzed earlier.