MILCOM 2008 - 2008 IEEE Military Communications Conference最新文献

{"title":"Assessing the impact of geographically correlated network failures","authors":"Sebastian Neumayer, G. Zussman, R. Cohen, E. Modiano","doi":"10.1109/MILCOM.2008.4753111","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753111","url":null,"abstract":"Communication networks are vulnerable to natural disasters, such as earthquakes or floods, as well as to human attacks, such as an electromagnetic pulse (EMP) attack. Such real-world events have geographical locations, and therefore, the geographical structure of the network graph affects the impact of these events. In this paper we focus on assessing the vulnerability of (geographical) networks to such disasters. In particular, we aim to identify the location of a disaster that would have the maximum effect on network capacity. We consider a geometric graph model in which nodes and links are geographically located on a plane. Specifically, we model the physical network as a bipartite graph (in the topological and geographical sense) and consider the set of all vertical line segment cuts. For that model, we develop a polynomial time algorithm for finding a worst possible cut. Our approach has the potential to be extended to general graphs and provides a promising new direction for network design to avert geographical disasters or attacks.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123101550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predictive handover mechanism based on required time estimation in heterogeneous wireless networks","authors":"S. Yoo, D. Cypher, Nada Golmie","doi":"10.1109/MILCOM.2008.4753602","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753602","url":null,"abstract":"In most conventional layer 2 triggering approaches, a pre-defined threshold for a specific perspective such as the received signal strength is used so that it may cause too late or too early handover executions. In this paper we propose a new predictive handover framework that uses the neighbor network information to generate timely the link triggers so that the required handover procedures can appropriately finish before the current link goes down. First we estimate a required handover time for the given neighbor network conditions, then using a predictive link triggering mechanism the handover start time is dynamically determined to minimize handover costs. The handover costs are analyzed in terms of the total required handover time and the service disruption time. The numerical analysis and simulation results show that the proposed method significantly enhances the handover performance.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"217 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124286732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Price based bifurcation control for finite buffered slotted ALOHA protocol with finite users","authors":"A. Sharifi, E. Abed","doi":"10.1109/MILCOM.2008.4753420","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753420","url":null,"abstract":"This paper studies the nonlinear instability and bifurcation in a slotted ALOHA system with finite users with finite user buffer capacity. Also effects of a price based control on eliminating the bifurcation phenomenon for the system is studied. It will be shown that the price based bifurcation control stabilizes the system by eliminating the bifurcation of the equilibrium points which occurs in the original system. The performance analysis of the system with price based bifurcation control is based on a well known approach called user tagged analysis. In this approach it is assumed that the channel is symmetric and therefore, behavior of all terminals is the same and hence the behavior of an arbitrarily chosen terminal is studied at equilibrium.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"319 8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120892825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mitigating naval network instabilities with disruption toler","authors":"C. Rigano, K. Scott, J. Bush, R. Edell, S. Parikh, R. Wade, B. Adamson","doi":"10.1109/MILCOM.2008.4753355","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753355","url":null,"abstract":"We describe an approach to improving network performance in networks with heterogeneous links - for example, a communications network constructed from satellite links, airborne relays, and line-of-site radios - using disruption tolerant networking. DTN defines an overlay network that uses storage at each hop to make end-to-end communications resilient to delay, loss, network disruption, temporary network partitioning, and congestion. DTN further improves performance by allowing separate transport layers at each hop of the overlay that can be tuned for the local network environments. We present recent work interfacing one such transport layer, the NACK oriented reliable multicast (NORM) protocol, to DTN; performance experiments from tactical radios; and simulation results based on models of deployed systems.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"184 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121039863","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic Spectrum Access: Architectures and implications","authors":"C. Tran, R. P. Lu, A. D. Ramirez, C. B. Phillips, S. Thai","doi":"10.1109/MILCOM.2008.4753454","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753454","url":null,"abstract":"The electromagnetic (EM) spectrum is the lifeblood of wireless communications and services. Accessing the spectrum has become ever-increasingly problematic. This is due to the current practices of frequency management based on pre-planned and static frequency allocation and assignments that can no longer accommodate explosive demands for EM spectrum. Without a paradigm shift in spectrum management, the growth of wireless services to meet demands, whether from commercial, civil, or military interests, will be severely curtailed in the coming years. In particular, spectrum-dependent devices, equipment, and systems will increasingly encounter significant competitive disadvantages, with critical consequences on our warfighting capability, when accessing the (seemingly or actually) overcrowded EM spectrum upon deployment in the U.S., and more so overseas. On the road forward, the transformation of spectrum management from the current static spectrum allocation and assignment to a more dynamic and responsive regime is greatly facilitated by the emerging concept of dynamic spectrum access (DSA) that enables spectrum-dependent devices, equipment, and systems to dynamically change their parameters to adapt their spectrum access according to criteria such as policy constraints, spectrum availability, propagation environment, and application performance requirements. In this paper, we present an overview of DSA architectures - opportunistic as well as coordinated, highlight their salient features, and focus on their implications on radios, networks, and spectrum usage which will provide responsive tactical and enabling strategic capabilities to the warfighter.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121241114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Channel mismatch compensation for space-time adaptive processors","authors":"N. Tisdale, T. Kazmierski, D. Brooks","doi":"10.1109/MILCOM.2008.4753528","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753528","url":null,"abstract":"Mismatches in the response of the components used in the analogue front-ends of adaptive beamformers can reduce their ability to produce deep nulls against broadband interferers. These mismatches can be removed through a process of calibration performed at start-up and, if required, on a regular basis to track changes in the componentpsilas response due to environmental changes. In this paper a hardware efficient scheme for compensating for channel mismatches is proposed based on pre-equalization of each channel using frequency domain equalization. The effectiveness of the proposed scheme is simulated and the improvement in broadband nulling is demonstrated on a hardware implementation of an adaptive beamformer.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127412823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Demonstration of two-way Extremely High Frequency (EHF) satellite communication (SATCOM) using submarine-survivable phased arrays","authors":"M.W. Atwood, G. Marcoux, W. Craig","doi":"10.1109/MILCOM.2008.4753497","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753497","url":null,"abstract":"U.S. submarines are faced with the challenging dilemma of addressing the need for higher data rate satellite communications (SATCOM) without significantly increasing the size of the SATCOM antenna. The planar form factor of phased array technology, along with the ability to steer beams electronically, has led to submarine antenna concepts that can simultaneously improve performance, utilize the submarine sail volume more efficiently, and minimize the impact to platform stealth. Through technology development under the Office of Naval Research (ONR), submarine-survivable phased arrays that address EHF SATCOM have been fabricated, tested, and delivered to the Navy by Boeing Phantom Works. The Naval Undersea Warfare Center has recently performed notional system integration and testing of these arrays. Q-band (44 GHz) uplink- and K-band (20 GHz) downlink-phased array antennas were tested successfully using both the military strategic and tactical relay (MILSTAR) and ultra high frequency follow-on (UFO) military satellites. The antennas were integrated with the Raytheon Follow-On Terminal (FOT) for full-duplex SATCOM testing. Full-duplex data rates of up to 64 kbps were attained using the phased arrays under optimal weather conditions. Bit error rate testing (BERT) was performed with no bit errors recorded. Initial tests were performed with the phased arrays mounted on a stationary platform; subsequent testing involved integration of the phased arrays into a notional housing atop a submarine mast. Notional mast testing included simulated ship motion using a six-axis motion table that is located on the roof of the Naval Undersea Warfare Center Division Newport's (NUWCDIVNPT) Building 68 (B-68) with support from the Submarine EHF Satellite Communication Integration Facility (SESIF). Half-duplex testing was also performed using a fiber optic (FO) link to carry both the control and radio frequency (RF) signals for the downlink-phased array on a single FO cable. This paper will provide an overview of the array technology and will describe the configurations and results of SATCOM testing.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"242 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125767968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance analysis of a JTIDS/Link-16-type waveform transmitted over Nakagami fading channels with pulsed-noise interference","authors":"C. Kao, F. Kragh, C. Robertson","doi":"10.1109/MILCOM.2008.4753275","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753275","url":null,"abstract":"The Joint Tactical Information Distribution System (JTIDS) is the communication terminal of Link-16. JTIDS is a hybrid direct sequence/frequency-hopping spread spectrum system and features Reed-Solomon codes for channel coding, cyclic code-shift keying for 32-ary symbol modulation, minimum-shift keying for chip modulation, symbol interleaving, chip sequence scrambling and random jittering for transmission security, and a double-pulse structure for diversity. Assuming that coherent chip demodulation is practical, we investigate the probability of symbol error of a JTIDS/Link-16-type waveform for both the single- and the double-pulse structure transmitted over a slow, flat Nakagami fading channel in the presence of pulsed-noise interference (PNI) in this paper. In general, the results show that the double-pulse structure always outperforms the single-pulse structure, whether the PNI is present or not and whether the channel is fading or not. Furthermore, barrage noise interference has the most effect in degrading performance when signal-to-interference ratio (SIR) is small. When SIR is large, PNI with a smaller fraction of time that interference is on causes the greatest degradation.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126057843","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oscillator mismatch and jitter compensation in concurrent codecs","authors":"W. L. Bahn, L. Baird, M.D. Collins","doi":"10.1109/MILCOM.2008.4753302","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753302","url":null,"abstract":"The advent of concurrent coding theory means that omnidirectional communication systems can possess a level of keyless jam-resistance comparable to that of traditional spread spectrum systems, all of which rely on shared secret keys. To achieve this, concurrent codecs possess the ability to efficiently separate multiple legitimate codewords that have been superimposed. This is achieved by leveraging a highly asymmetric sensitivity to bit errors and, consequently, a reliance on communication channels having correspondingly high degrees of asymmetry in their bit error probabilities. While suitable physical channels must possess inherently high degrees of asymmetry, this asymmetry can be artificially enhanced using post processing techniques with the effect that system designers can trade small amounts of jam-resistance for increases in noise immunity. Furthermore, to rob potential adversaries of the option of attacking the receiverpsilas ability to synchronize with the transmitted signal, concurrent codecs do not perform real-time adaptive synchronization and instead use asynchronous protocols. To avoid bit misalignments over the length of the packet, such protocols normally require that transmitters and receivers have oscillators with frequency tolerances on the order of one part in ten times the packet length. However, a concurrent codec can use simple post-processing techniques to exploit the asymmetry in bit error sensitivity to give receivers high degrees of immunity to timing jitter as well as high tolerances to oscillator mismatch. This has implications not only for processing gain, but also for implementation cost since transceivers can utilize oscillators having greatly relaxed specifications compared to that required by traditional systems. This paper presents these techniques and analyzes their impact on jam-resistance and oscillator performance requirements.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126099106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An analytical study of precedence and QOE for voice service in degraded IP networks","authors":"J. Pitts, J. Schormans","doi":"10.1109/MILCOM.2008.4753406","DOIUrl":"https://doi.org/10.1109/MILCOM.2008.4753406","url":null,"abstract":"The performance evaluation of mechanisms that can support precedence and pre-emption in a converged IP infrastructure is a challenging task. This paper provides approximate analysis to investigate the trade-off between VoIP call blocking and quality of experience in a DiffServ environment. Mathematical formulations are developed for EF and AF configurations incorporating token bucket, tail-drop and WRED mechanisms. Results are presented for a T1 access link over which G.711 VoIP calls are multiplexed as one class within a multi-service user demand mix. The analysis enables the quality degradation associated with precedence and pre-emption techniques to be estimated, and indicates that the impact on lower precedence traffic is not as severe as hitherto feared. This opens up the possibility of developing more flexible and scalable approaches to implementing MLPP concepts in a converged IP network infrastructure.","PeriodicalId":434891,"journal":{"name":"MILCOM 2008 - 2008 IEEE Military Communications Conference","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126626723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}