Phong C. Khuu

An Efficient Intranet Networking Solution for Airborne Networks

We illustrate a novel wireless intranet networking protocol providing the flexibility and efficiency needed to operate in airborne environments. A critical component of this protocol is an efficient mobile ad-hoc networking (MANET) design, known as adaptive hybrid domain routing (AHDR) protocol, devised primarily for airborne networking. We describe the driving networking requirements and tradeoffs, protocol architecture, and measured and simulated performance. The MANET element in this protocol is composed of a strategic combination of proactive and reactive algorithms. It provides updated route information for neighbor nodes and offers optimized route resolution for unknown routes in a fast-changing topology. The set of optimization parameters for making routing decisions is configurable via a network management module. The selection of the best route, data rate, transmission power, message format, frame length, and transmission time is distributed and depends on real-time optimization parameters

Adaptive Management of Scalable Mobile Ad-Hoc Networks with Non-homogeneous Topology

In this paper, we discuss the management of scalable mobile ad-hoc networks (MANET) in which nodes are equipped with a range of adjustable capabilities (transmission range, data rate, and radio interface, etc.) and operate in quite diverse environment (in terms of channel condition and node density, etc.). To support communication in such a dynamic networking environment requires a MANET protocol that is adaptable to spatial and temporal changes. As such, it is crucial to optimize node/link controllability so that node/link resources can be best utilized and a good performance can be achieved. Moreover, it is also necessary to feature statistical measures when evaluating the performance, such as the variance of these metrics in addition to the average. As an extension of our previous research, we continue to study Adaptive Hybrid Domain Routing (AHDR) protocol in regard to the effectiveness of the flooding architecture. We also evaluate various topology control techniques that ensure guaranteed service to disadvantaged nodes and across critical links (sparse connectivity). These efforts serve as very first steps to comprehensively study the impact of network non-homogeneity and variance in topology management.

A PMP-Friendly MANET Networking Approach for WiMAX/IEEE 802.16/sup TM/

WiMAX Forum certifiedtrade broadband wireless equipment is now available to military users and consumers alike. This equipment is based on the IEEE 802.16/sup TM/-2004 and IEEE 802.16e/sup TM/-2005 standards. This commercial off-the-shelf (COTS) equipment promises to greatly reduce the cost of broadband wireless access and lead to cost-effective solutions for the military. However, existing COTS equipment has performance deficiencies when considered for military and national security operational scenarios. One deficiency is the lack of mobile ad-hoc and mesh networking capabilities compatible with the currently fielded point-to-multipoint (PMP) mode. While the IEEE 802.16-2004 standard includes a mesh capability, it does not interoperate with the PMP mode, and is not being considered for implementation. The IEEE 802.16e-2005 amendment addresses subscriber mobility but does nothing to address the ad-hoc and mesh shortcomings in WiMAX and IEEE 802.16-2004. This paper reviews some current and planned capabilities of WiMAX, and recommends extensions to the IEEE 802.16 standard to facilitate mobile ad-hoc and mesh networking protocols that can interoperate with planned WiMAX deployments

Integrating Local Neighborhood Congestion and Path Stability into QoS Routing for Tactical Networks

Routing protocols for wireless Mobile Ad Hoc Networks (MANETs) have been explored extensively in recent years. However, most of the work thus far has focused on finding a feasible route from a source to a destination in a timely and efficient manner without considering the impact on the transport performance of existing application traffic or the newly added flows. As a result, parts of the network become saturated with no means of adaptively compensating for or routing traffic around the overloaded areas, thereby lowering network efficiency. While this limitation may be acceptable for best-effort or delay-tolerant data transfers, real-time applications often require a certain level of Quality-of-Service (QoS) from the network. A comprehensive QoS-enabled MANET solution benefits from a QoS-aware routing scheme that considers the applications transport requirements and the data transport conditions of available paths. We propose a distributed multi-path QoS-aware routing scheme that leverages common MANET characteristics (e.g., neighborhood congestion and path stability) to meet the transport service requirements of real-time applications. The QoS routing scheme implements a method of superimposing distributed neighborhood congestion, neighborhood density, link stability and delay information over multiple discovered paths when calculating the next hop decision. In addition, the solution increases overall network capacity by using otherwise idle network resources. In this paper, we discuss multi-path discovery, the associated QoS metric calculations, and the QoS-aware path selection process.

QoS Management in Disadvantaged Tactical Environments

The tactical Network is one of the major components in DoD Global Information Grid (GIG). The key challenge of quality of service (QoS) management tactical networks is how to deal with negative factors that result from varying network capability demanding and a disadvantaged physical environment. These factors could include network mobility, dynamic network formation, unusual network protocol behaviors, communication channel fading, channel bandwidth fluctuation, as well as platform/application characteristics. This paper investigates the challenges of several well-known QoS management mechanisms in disadvantaged tactical network environments and provides some recommendations on the directions of mitigations and improvements.

Efficient Dissemination Techniques for MANET Routing Control Messages

The challenges of optimal flooding of network control messages in Mobile Ad-Hoc Network (MANET) have been well studied in the literature [2]-[10] and [12]-[19]. A particular case of this problem is encountered in MANET routing protocols, which need to distribute routing control information to all member nodes as efficiently as possible. While both proactive and reactive MANET routing protocols exist, in some environments a proactive approach will be used to reduce communications latency as much as possible. Even in a hybrid protocol, the proactive portion requires some amount of information exchange among all nodes. Many previous papers have discussed optimal flooding in a variety of environments under a variety of assumptions, but none have assessed the performance of a recently developed cluster based routing protocol called Adaptive Hybrid Domain Routing (AHDR). In this paper, the optimal flooding architecture developed for the clustered based AHDR protocol is discussed in detailed. The paper also compares AHDRs flooding architecture against two prominent MANET routing protocols, OLSR [3] and OSPFMDR [11]. The paper also shows simulation results for each of the flooding architectures using an unbiased and non-intrusive monitoring technique. The performance results show that AHDRs flooding architecture imposes lower overhead control traffic as compared to OLSR and OSPF-MANET-MDR while still providing better network reachability.

Use of DoDAF and M&S for the Design Requirements and Optimization of a GIG-Enabled Wideband Mesh-Networking Waveform

As the DoD evolves its network-centric infrastructure to support transformation, there is an increasing need to use a structured process to develop and optimize GIG-enabled networked communications and their underlying waveform layers. This paper describes an approach to this problem using DoD architecture framework (DoDAF), which has been tailored (waveform DoDAF) for the development of networked communication waveforms. We also cover the network modeling and simulation (M&S) process which supports validation and optimization of the resulting waveform protocols. The challenge of todays communication waveform specification working groups centers around the problem of generating a waveform that maximizes customer utility and data throughput, while effectively managing network connectivity, quality of service, and spectrum use. Existing, ad-hoc waveform specification methods lack operational discipline and typically do not result in a waveform meeting DoD needs. The waveform DoDAF methodology centers on a systematic transfer function from operational views (OVs), through communication laydowns or system views (SVs), to detailed waveform requirements. Using this process, complex multi-access mechanisms, physical layer attributes and layer 2/3 protocols are linked to operationally-based drivers, not stove-piped engineering concepts. An overview of each step of the process is covered, along with examples of OV, SV, and waveform views for key network-centric use-case scenarios. The paper includes a waveform application example showing the successful use of waveform DoDAF for the generation of a GIG-enabled, high capacity, RF wideband mesh networking waveform. The approach described in this paper can be used for all types of communication waveforms, including narrowband RF, wideband RF, and free-space optical (FSO) communications.