The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Scalable video coding (SVC) is a standardized extension to the widely accepted H.264/MPEG-4 advanced video coding (AVC) standard. SVC provides scalability at a bit stream level and allows multiple formats of a single video source to be encoded in a single video stream. This facilitate the delivery of video content to a diverse set of end users with a variety of receive device capabilities, over transmission...
Shipboard communications architectures that couple multiple radio frequency channels to a limited number of antennas have typically relied upon the use of cavity-tuned, electromechanically-based multicouplers. Using this approach, sufficient channel isolation can be obtained to minimize mutual, cosite interference among the various channels, however, the required multicouplers are large, expensive...
Todaypsilas military-based communication programs are attempting to leverage software defined radio (SDR) technology for reducing lifecycle costs by promoting the reuse of waveform software. Although an SDR offers the developer flexibility for software development; porting a waveform application from one SDR to another can be challenging due to variations in requirements, software operating environment...
An enabling concept of joint tactical radio system (JTRS) to provide global connectivity to the warfighter is the development of radio waveforms and applications that can be readily ported to different members of the JTRS radio family. Waveform porting is a pragmatic realization that ubiquitous plug-and-play is not possible for tactical radios possessing different hardware architectures and missions...
With the advancement of broadband networking technology, many clients are enabled to enjoy various video on demand (VoD) services. To provide VoD services to a number of clients, the network needs to consider various factors together; they are each viewerpsilas waiting time, buffer requirement at the client, channel management for video delivery, and complexity for video segmentation. Among the currently...
Tactical naming service is a critical component of tactical communications systems, which provides essential name-address resolution and service discovery for tactical users. Generally speaking, tactical users of land communications systems can be categorized into stationary HQ users (users in headquarters network), mounted users (users in vehicle networks), and dismounted users (users in mobile ad...
A complete situational awareness requires that an interested party be able to receive information form multiple sources at the same time. With bent pipe satellites a destination terminal can receive data only from a single source terminal at any given time. We analyze the key features of the next generation satellites that have packet processing capability within the satellite. An attractive capability...
Cooperative systems, like those found in networks of unmanned aerial vehicles (UAVs) and unmanned ground vehicles (UGVs), are typically distributed over large geographical areas. This geographic dispersion forces reliance on wireless communications to implement the control systems for these networks. As the number of nodes within the system grows, the bandwidth required to continuously update all...
Estimating the location of a point source at the output of an array system can be challenging, especially when one needs to make the tradeoff between accuracy and computational complexity. Using a rectangular array, the most widely studied parameter estimation problem is the azimuth and elevation only case. Even in this two parameter case, it usually requires a two-dimensional search in order to obtain...
Diverse security applications often require monitoring of a narrow passage, such as an indoor corridor, a tunnel, a bridge; either to protect critical assets at the end of such a passage or to control the passage over it, or both. Often, sensors are arranged in a vector along such a passage and are capable of registering the crossing of a target but not its identity. In this paper, we consider coordinated...
A system of three adaptive cancellers for amplitude jitter, Doppler shift, and phase jitter, cascaded one after another and working jointly for simultaneously canceling of these impairments, is discussed in the paper. The optimal cancellation and the impact of the order of cancellations are also discussed. Computer simulations demonstrate that although there is nonlinear interaction among the transmission...
Knowledge of the direction of arrival (DOA) of a signal is useful both in civil applications such as mobile communications and also in military related applications as well. Even though asynchronous wise both applications are same, they are not when the number of sources are considered. This paper considers the problem of estimating the DOA of users in an asynchronous DS-CDMA system where the technique...
An M-ary time reversal (TR) maximum likelihood classifier for a single pair of transmitting and receiving transducer element was derived in for underwater acoustic target detection applications. This paper considers a more general TR setup consisting of a P-element transmitting array and an N element receiving array and derives the M-ary conventional and TR classifiers for the multielement case in...
Two existing network security problems are ensuring anonymous communications and preventing data exfiltration through network covert channels. We present a new concept in network addressing: one-time encrypted network addresses. We describe a particular instantiation: one-time CPP addresses. We then show how one-time encrypted addresses can prevent intersection and other traffic analysis attacks that...
Maintaining strategic advantage in modern warfare requires the deployment and use of cryptographic systems to ensure the confidentiality and integrity of vital communications between operational elements. The ability to accomplish this goal imparts a sense of confidence both to the receiver that information originated unmodified from a trusted source and to the sender that it will be read by only...
Anyone who administers a personal computer, either on the job or at home, is familiar with the concept of rapid software reprogramming (RSR). Operating system and many application software vendors perform reprogramming via electronically-delivered patches, service packs, or similar means. In the battlefield, RSR extends to embedded systems, both hand-held and vehicle-mounted, as well as to the military...
Certificate validation in tactical wireless networks and MANETs is a hard problem, due to low bandwidth and frequent disconnections. We suggest a cooperative caching approach with an overlay network of XKMS proxies. The overlay network is discovered and maintained with only marginal increase in the network traffic. This is due to a cross layer design where the XKMS proxies tap into the OLSR routing...
The need for accurately characterizing the spatial domain of the wireless channel has become increasingly important with the growing use of wireless technology. To facilitate the development of signaling strategies and Multiple-Input Multiple-Output (MIMO) system architectures, many different channel modeling strategies have been employed. When it is desirable to create many different channel matrix...
One of the basic problems in maritime tactical networks is how to maximize the quality of service (QoS) achieved by critical traffic while dealing with mobile and limited-capacity links. This paper describes an evaluation of the resource reservation service (RRS), a distributed admission control protocol designed to guarantee end-to-end bandwidth for critical traffic in the maritime environment. The...
The Mobile Ad hoc Network Emulator (MANE) test bed relies on accurate determination of radio signal propagation to emulate realistic mobile ad hoc network (MANET) connectivity. The determination of radio wave propagation is a very complex process that depends on numerous factors such as the transmitting medium (e.g., vacuum, air, or water), antenna properties of transmitters and receivers, and the...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.