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The emerging technologies of multiple, cooperative unmanned systems have brought in an exciting period of possibilities, possibilities of solving challenging problems in medical, social, engineering, and military communities. The technologies have also introduced a growing number of new challenges such as resource allocation, communication and coordination, establishment of consensus, and control...
This paper presents an analysis of satellite communications (SATCOM) systems that use Internet protocol (IP) with quality of service (QoS) metrics, and addresses IP efficiency measures. Key contributing elements for the IP efficiency are network structure, provisional efficiency, and bandwidth-on-demand features. IP bandwidth gains will also depend on the network size, the level of hierarchy, and...
One of the major QoS goals for future battlefield networks (FBN) is to ensure multi-level precedence and preemption (MLPP). Ensuring MLPP is difficult, partly due to the networking architecture for FBN which consists of wired ??red?? network connected by encrypted wireless ??black?? network. The security requirements for FBN do not allow passing information from black to red networks. So when congestion...
A new and novel spread spectrum approach employing orthogonal frequency coding (OFC) for a SAW sensor/tag is presented. This approach provides ultra wide band operation, multi-device interrogation, and reduced loss as compared to conventional SAW CDMA approaches. A traditional SAW CDMA tag consists of an input transducer that launches a surface wave on the substrate towards an array of single frequency...
Dynamic spectrum access (DSA) provides a more flexible spectrum management method versus the current command and control method and promises much higher spectrum utilization efficiency. By this paradigm, secondary users can use vacant spectrum while guaranteeing non-interference to incumbent users. Therefore, spectrum awareness is a required function in DSA, and cooperative spectrum sensing is widely...
The Defense Information Systems Agency (DISA) has been supporting dissemination of airborne sensor Full Motion Video (FMV) since the inception of the Global Broadcast Service (GBS). DISA actively investigates emerging video technologies and participates in DoD and industry conferences related to FMV. In 2006, DISA increased its involvement in FMV dissemination through support to several US Central...
A multisymbol noncoherent receiver suitable for coded continuous-phase frequency-shift keying is developed and analyzed. Unlike coherently detected signals, the modulation index of the waveform does not need to be rational with a small denominator, and the oscillator only needs to be stable for the duration of a small group of symbols. The receiver is analyzed in terms of its symmetric information...
Tactical mobile ad hoc networks (MANETs) have a continued growth in bandwidth demand mainly driven by the introduction of new user services and applications. Everything over IP is one of the main requirements of the next generation tactical MANETs. As part of an initial investigation to provide enhanced tactical IP networking capabilities, an adaptive VHF/UHF system that attempts to satisfy the mobility,...
With the continuing launch of the wideband global satellite communications (WGS) constellation, the Department of Defense (DoD) will have the opportunity to transition many existing military satellite communications networks from commercial satellite bandwidth to the military-owned satellite resources. Transition to WGS will provide the warfighter with additional capacity to augment future satellite...
This paper presents simulation results which illustrate the performance of a fast frequency hopped - frequency division multiple access (FFH-FDMA) satellite communication system using a partial processing dehop-rehop transponder (DRT) under jamming. In the simulated system, convolutional coded symbols (using rates 1/2 or 1/4) are hopped with time diversity to enhance the anti-jamming (AJ) capacity...
Warfighters in today's asymmetric engagements need access to mission-critical information no matter when and where it becomes available. Information Management Services (IMSs) based on publish-subscribe-query services have emerged as an important enabler of tactical information dominance in combined tactical and enterprise military situations. IMSs support information brokering and dissemination between...
A network intrusion detection (ID) system detects malicious behavior by analyzing network traffic. Malicious behavior may target the disruption of communications, infrastructure services, and applications. A number of ID techniques proposed for dynamic wireless networks (e.g., sensor, ad-hoc and mobile ad-hoc networks) are based on the creation of an overlay hierarchy or other structure to organize...
Telecommunication networks spanning large areas are subject to various failures. A survivable network provisioning scheme addressing multiple levels of network failures, especially disaster failures which may take out many network components, is desirable in the future Internet. In this study, we propose and investigate the characteristics of a multistate multipath provisioning scheme for telecom...
The wideband global satellite (WGS) system represents an order of magnitude increase in capacity over the existing defense support communications satellite (DSCS) system. In addition to adding capability in the X-band and a Ka-band, WGS adds a unique digital channelizer. The digital channelizer greatly increases the flexibility of the WGS payload over previous satellite systems. It allows an individual...
In this paper, we present three novel priority-based spectrum allocation techniques for enabling dynamic spectrum access (DSA) networking for non-contiguous orthogonal frequency division multiplexing (NC-OFDM) transmission. With each communication link in the network possessing a specified pair of bit error rate (BER) and throughput requirements for supporting a specific application, the proposed...
Tactical air-to-ground channels present a number of challenges for physical (PHY) layer waveform design including: (i) airborne platform dynamics (i.e., Doppler, frequency offset, jerk, etc.), (ii) benign to severe ground-level multipath, and (iii) partial to full blockage of the line-of-sight (LOS) path. Legacy military waveforms are not sufficiently robust to operate effectively in these severe...
It is widely known that TCP's congestion control algorithm can cause it to under-perform when round trip times and error rates are high. Performance Enhancing Proxies (PEPs) can improve performance by breaking end-to-end TCP connections and using a separate, tuned transport protocol to transit 'stressed' links. While PEPs can be tuned to work well when a single pair of PEPs bracket a fixed-rate link,...
This paper presents the ultra-wideband (UWB) channel measurement and modeling for an intra-vehicle environment. The measurement was conducted in time domain beneath a commercial vehicle chassis. Channel data were collected at the same locations for the car in stationary and in moving status. Stochastic tapped delay line model is used to characterize the channels in both cases. Slightly larger number...
In wireless networks, the limited available bandwidth combined with varying signal propagation conditions make it necessary to pursue optimization across all layers of the protocol stack in order to boost the achievable throughput. One of the optimization strategies that is deemed to be effective is to dynamically adjust the packet size either to better suit the channel conditions or to minimize the...
Network centric warfare relies on the timely and reliable delivery of data to disparate cooperating nodes in tactical networking environments. Given the limited bandwidth available and the unreliability of network links, data often accumulates in application and/or network queues, resulting in increased latency in the delivery of the data. The Mockets communications library addresses this problem...
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