Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415863
C. McLain, Sunil Panthi, M. Sturza, J. Hetrick
Recent advancements in Ku-band high throughput satellites (HTS) will allow commercial Ku-band aeronautical mobile satellite systems (AMSS) to equal or exceed commercial Ka-band AMSS systems on cost and performance. The AMSS market is currently dominated by Ku-band solutions, both in the commercial sector (eXConnect, Row44, Yonder) and the government sector (Tachyon, Boeing Broadband Satellite Network (formerly Connexion), various UAV and ISR systems). All of these systems use conventional continental-scale wide beams that are leased from Fixed Satellite Service (FSS) providers such as Intelsat and Eutelsat. In the next several years the dominance of Ku-band AMSS will be challenged by Ka-band systems such as Inmarsat-5, which use multiple spot beams to offer enhanced performance. Previous work has suggested that these systems may offer better performance and better economics than conventional Ku-band systems [1]. The key insight of this paper is that the performance advantage of spot beam Ka-band systems comes from their smaller beam size rather than their frequency of operation, meaning that a Ku-band spot beam satellite can also be built with similar sized spot beams to Ka-band systems and can achieve competitive cost and performance as compared to a Ka-band spot beam systems. High throughput spot beam Ku-band systems, such as Intelsat's EpicNG system, are now in development and will be fielded in the same timeframe as Inmarsat-5. This result has critical implications for existing users and operators of AMSS systems: - Currently installed Ku-band terminals will be able to take advantage of dramatic improvements in performance when high throughput Ku-band becomes available - Current Ku-band will not have to undergo costly Ka-band retrofits to maintain competitive performance - Operators can continue to invest in Ku-band terminals today without fear of obsolescence in the near future - The AMSS market will continue to be diverse and competitive for years to come.
{"title":"High throughput Ku-band satellites for aeronautical applications","authors":"C. McLain, Sunil Panthi, M. Sturza, J. Hetrick","doi":"10.1109/MILCOM.2012.6415863","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415863","url":null,"abstract":"Recent advancements in Ku-band high throughput satellites (HTS) will allow commercial Ku-band aeronautical mobile satellite systems (AMSS) to equal or exceed commercial Ka-band AMSS systems on cost and performance. The AMSS market is currently dominated by Ku-band solutions, both in the commercial sector (eXConnect, Row44, Yonder) and the government sector (Tachyon, Boeing Broadband Satellite Network (formerly Connexion), various UAV and ISR systems). All of these systems use conventional continental-scale wide beams that are leased from Fixed Satellite Service (FSS) providers such as Intelsat and Eutelsat. In the next several years the dominance of Ku-band AMSS will be challenged by Ka-band systems such as Inmarsat-5, which use multiple spot beams to offer enhanced performance. Previous work has suggested that these systems may offer better performance and better economics than conventional Ku-band systems [1]. The key insight of this paper is that the performance advantage of spot beam Ka-band systems comes from their smaller beam size rather than their frequency of operation, meaning that a Ku-band spot beam satellite can also be built with similar sized spot beams to Ka-band systems and can achieve competitive cost and performance as compared to a Ka-band spot beam systems. High throughput spot beam Ku-band systems, such as Intelsat's EpicNG system, are now in development and will be fielded in the same timeframe as Inmarsat-5. This result has critical implications for existing users and operators of AMSS systems: - Currently installed Ku-band terminals will be able to take advantage of dramatic improvements in performance when high throughput Ku-band becomes available - Current Ku-band will not have to undergo costly Ka-band retrofits to maintain competitive performance - Operators can continue to invest in Ku-band terminals today without fear of obsolescence in the near future - The AMSS market will continue to be diverse and competitive for years to come.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"36 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81081107","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415842
Hellen Maziku, S. Shetty, Keesook J. Han, Tamara Rogers
The ability to localize Internet hosts is appealing for a range of applications from online advertising to localizing cyber attacks. Recently, measurement-based approaches have been proposed to accurately identify the location of Internet hosts. These approaches typically produce erroneous results due to measurement errors. In this paper, we propose an Enhanced Learning Classifier approach for estimating the geolocation of Internet hosts with increased accuracy. Our approach extends an exisiting machine learning based approach by extracting six features from network measurements and implementing a new landmark selection policy. These enhancements allow us to mitigate problems with measurement errors and reduces average error distance in estimating location of Internet hosts. To demonstrate the accuracy of our approach, we evaluate the performance on network routers using ping measurements from PlanetLab nodes with known geographic placement. Our results demonstrate that our approach improves average accuracy by geolocating internet hosts 100 miles closer to the true geographic location versus prior measurement-based approaches.
{"title":"Enhancing the classification accuracy of IP geolocation","authors":"Hellen Maziku, S. Shetty, Keesook J. Han, Tamara Rogers","doi":"10.1109/MILCOM.2012.6415842","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415842","url":null,"abstract":"The ability to localize Internet hosts is appealing for a range of applications from online advertising to localizing cyber attacks. Recently, measurement-based approaches have been proposed to accurately identify the location of Internet hosts. These approaches typically produce erroneous results due to measurement errors. In this paper, we propose an Enhanced Learning Classifier approach for estimating the geolocation of Internet hosts with increased accuracy. Our approach extends an exisiting machine learning based approach by extracting six features from network measurements and implementing a new landmark selection policy. These enhancements allow us to mitigate problems with measurement errors and reduces average error distance in estimating location of Internet hosts. To demonstrate the accuracy of our approach, we evaluate the performance on network routers using ping measurements from PlanetLab nodes with known geographic placement. Our results demonstrate that our approach improves average accuracy by geolocating internet hosts 100 miles closer to the true geographic location versus prior measurement-based approaches.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"6 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81946605","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415608
Sébastien Marcille, P. Ciblat, C. Martret
This paper deals with multiuser resource allocation (power, bandwidth, constellation size, and code rate) for an OFDMA system using HARQ in the context of Rayleigh distributed channel. We assume that the resource manager (base station or cluster head) only knows the channel statistics of the active links. Then, an optimal algorithm for minimizing the total transmitted power under per user goodput constraints is proposed. Extension to imperfect feedback on HARQ scheme is also performed. This algorithm can be especially applied to military ad hoc wireless networks.
{"title":"Optimal resource allocation in HARQ-based OFDMA wireless networks","authors":"Sébastien Marcille, P. Ciblat, C. Martret","doi":"10.1109/MILCOM.2012.6415608","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415608","url":null,"abstract":"This paper deals with multiuser resource allocation (power, bandwidth, constellation size, and code rate) for an OFDMA system using HARQ in the context of Rayleigh distributed channel. We assume that the resource manager (base station or cluster head) only knows the channel statistics of the active links. Then, an optimal algorithm for minimizing the total transmitted power under per user goodput constraints is proposed. Extension to imperfect feedback on HARQ scheme is also performed. This algorithm can be especially applied to military ad hoc wireless networks.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"14 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81995318","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415586
V. Weerackody, E. Cuevas
Satellite Communications on-the-move (SOTM) networks are being deployed to provide various broadband communication services. Typically, an SOTM network consists of a large number of small aperture terminals deployed over a wide geographical area. These terminals are intended to operate over geostationary orbit satellites. To utilize network resources efficiently, these networks may employ time- and frequency-division multiple access methods. Also, SOTM terminals may operate using a range of antenna aperture sizes and may require different transmit power levels to meet various user's data rate needs. Additionally, antenna pointing errors of the terminals may contribute to a time-varying interference pattern from the SOTM network to a victim receiver in another satellite network. This paper provides a methodology to analyze the time-varying interference resulting from an MF-TDMA network consisting of such terminals. This methodology has been submitted for consideration by ITU-R Working Party 4A.
{"title":"Adjacent satellite interference from a network Of MF-TDMA satellite communications on-the-move terminals","authors":"V. Weerackody, E. Cuevas","doi":"10.1109/MILCOM.2012.6415586","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415586","url":null,"abstract":"Satellite Communications on-the-move (SOTM) networks are being deployed to provide various broadband communication services. Typically, an SOTM network consists of a large number of small aperture terminals deployed over a wide geographical area. These terminals are intended to operate over geostationary orbit satellites. To utilize network resources efficiently, these networks may employ time- and frequency-division multiple access methods. Also, SOTM terminals may operate using a range of antenna aperture sizes and may require different transmit power levels to meet various user's data rate needs. Additionally, antenna pointing errors of the terminals may contribute to a time-varying interference pattern from the SOTM network to a victim receiver in another satellite network. This paper provides a methodology to analyze the time-varying interference resulting from an MF-TDMA network consisting of such terminals. This methodology has been submitted for consideration by ITU-R Working Party 4A.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"302 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78436709","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415636
Seongah Jeong, Keonkook Lee, Joonhyuk Kang, Youngseok Baek, B. Koo
In this paper, we consider a cooperative jammer to improve secrecy of the wireless transmission in a cellular downlink network. The private message intended for a single user should be kept from the remainder of the users who are regarded as internal eavesdroppers. To improve the secrecy of the intended user, we propose an employment of a helper with multiple antennas and design its optimal transmit beamforming vector. Specifically, the helper node generates the artificial interference to the internal eavesdroppers and so enhances the security by increasing the ambiguity at the eavesdroppers. Based on a framework of power gain region in [1], we optimize the transmission strategy for the helper which maximizes the secrecy capacity of the intended user. The analytical and simulation results show that the proposed scheme enhances the secrecy capacity. In addition, all users whose secrecy rates are zero with no helper's cooperation can achieve the positive secrecy rate by the proposed scheme.
{"title":"Cooperative jammer design in cellular network with internal eavesdroppers","authors":"Seongah Jeong, Keonkook Lee, Joonhyuk Kang, Youngseok Baek, B. Koo","doi":"10.1109/MILCOM.2012.6415636","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415636","url":null,"abstract":"In this paper, we consider a cooperative jammer to improve secrecy of the wireless transmission in a cellular downlink network. The private message intended for a single user should be kept from the remainder of the users who are regarded as internal eavesdroppers. To improve the secrecy of the intended user, we propose an employment of a helper with multiple antennas and design its optimal transmit beamforming vector. Specifically, the helper node generates the artificial interference to the internal eavesdroppers and so enhances the security by increasing the ambiguity at the eavesdroppers. Based on a framework of power gain region in [1], we optimize the transmission strategy for the helper which maximizes the secrecy capacity of the intended user. The analytical and simulation results show that the proposed scheme enhances the secrecy capacity. In addition, all users whose secrecy rates are zero with no helper's cooperation can achieve the positive secrecy rate by the proposed scheme.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"34 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79171678","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415827
E. Egbogah, A. Fapojuwo, Liqi Shi
In this paper, we propose an energy-efficient transmission scheme for monitoring soldier health in tactical mobile ad hoc networks (T-MANET). In the proposed scheme, a constrained route discovery algorithm is used to determine feasible routing paths between the source nodes and sink node. A cross-layer optimization approach is then used to determine the optimal routes and minimum power required to transmit data in the military UHF band such that the end-to-end packet delivery ratio (PDR) and end-to-end delay objectives are met. However, the optimal solution requires exponential complexity and is not suitable for implementation in resource constrained sensor motes. Therefore, we propose a heuristic algorithm called joint link node power allocation (JPA) that allocates power based on the presence of joint link nodes. From the analysis and numerical results, we find that JPA achieves energy consumption that is within 24% of the optimal value, but significantly reduces the solution complexity from exponential to polynomial by utilizing 6 times fewer iterations than the optimal solution to converge to a minimum energy solution.
{"title":"An energy-efficient transmission scheme for monitoring of combat soldier health in tactical mobile ad hoc networks","authors":"E. Egbogah, A. Fapojuwo, Liqi Shi","doi":"10.1109/MILCOM.2012.6415827","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415827","url":null,"abstract":"In this paper, we propose an energy-efficient transmission scheme for monitoring soldier health in tactical mobile ad hoc networks (T-MANET). In the proposed scheme, a constrained route discovery algorithm is used to determine feasible routing paths between the source nodes and sink node. A cross-layer optimization approach is then used to determine the optimal routes and minimum power required to transmit data in the military UHF band such that the end-to-end packet delivery ratio (PDR) and end-to-end delay objectives are met. However, the optimal solution requires exponential complexity and is not suitable for implementation in resource constrained sensor motes. Therefore, we propose a heuristic algorithm called joint link node power allocation (JPA) that allocates power based on the presence of joint link nodes. From the analysis and numerical results, we find that JPA achieves energy consumption that is within 24% of the optimal value, but significantly reduces the solution complexity from exponential to polynomial by utilizing 6 times fewer iterations than the optimal solution to converge to a minimum energy solution.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"174 3","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91422718","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415748
Jeong Ho Yeo, Joon Ho Cho
In this paper, we show that a second-order cyclo-stationary (SOCS) random process, whether it is proper or improper, can be always converted to an equivalent proper-complex SOCS random process with twice the cycle period. A simple linear-conjugate linear periodically time-varying operator called a FREquency SHift (FRESH) properizer is proposed to perform this conversion. As an application, we consider the presence detection of an improper-complex SOCS random process, which well models the complex envelopes of digitally modulated signals such as pulse amplitude modulation (PAM), staggered quaternary phase-shift keying (SQPSK), Gaussian minimum shift keying (GMSK), etc. In particular, the optimal presence detector that utilizes the FRESH properizer is derived for improper-complex SOCS Gaussian random processes, which provides the lower bound on the detection error probabilities. The derived optimal detector, which has the structural advantage in that it consists of a FRESH properizer followed by a single linear filter, achieves the same performance as the conventional detector that consists of parallel-connected linear and conjugate-linear filters. Numerical results are also provided.
{"title":"Properization of second-order cyclostationary random processes and its application to signal presence detection","authors":"Jeong Ho Yeo, Joon Ho Cho","doi":"10.1109/MILCOM.2012.6415748","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415748","url":null,"abstract":"In this paper, we show that a second-order cyclo-stationary (SOCS) random process, whether it is proper or improper, can be always converted to an equivalent proper-complex SOCS random process with twice the cycle period. A simple linear-conjugate linear periodically time-varying operator called a FREquency SHift (FRESH) properizer is proposed to perform this conversion. As an application, we consider the presence detection of an improper-complex SOCS random process, which well models the complex envelopes of digitally modulated signals such as pulse amplitude modulation (PAM), staggered quaternary phase-shift keying (SQPSK), Gaussian minimum shift keying (GMSK), etc. In particular, the optimal presence detector that utilizes the FRESH properizer is derived for improper-complex SOCS Gaussian random processes, which provides the lower bound on the detection error probabilities. The derived optimal detector, which has the structural advantage in that it consists of a FRESH properizer followed by a single linear filter, achieves the same performance as the conventional detector that consists of parallel-connected linear and conjugate-linear filters. Numerical results are also provided.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"6 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90599647","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415673
J. McDermott, B. Montrose, Margery Li, J. Kirby, Myong H. Kang
In conventional military computing, security separation is provided by cryptography, for data in motion and data at rest. Security separation for data under computation is provided by separate hardware. Cloud computing shares hardware for all data under computation, so a new approach to security separation is needed for military clouds. Cryptographic separation of data under computation is not practical with current technology, so the separation must be accomplished by software, i.e. the virtualization infrastructure. The strongest known means of software separation is the separation kernel. Separation kernels are special virtual machine monitors (VMMs) that are small enough and simple enough to be mathematically verified. Unfortunately, strict separation kernels cannot virtualize the complex modern commodity hardware and guest virtual machine (VM) operating systems that are essential to cloud computing. The best alternative to a strict separation kernel is a a separation VMM. A separation VMM relaxes the strict size and simplicity goals of a separation kernel just far enough to be able to support commodity hardware and guest operating systems. Because they address all of the features of commodity hardware, separation VMMs are too large for formal mathematical verification. However, separation VMMs are small enough and simple enough to be completely specified by semiformal means, i.e. they are smaller and simpler than conventional VMMs. A separation VMM has a complete systematic assurance argument that it isolates guest VMs from each other and strongly protects itself from tampering. A separation VMM provides the strongest separation of cloud VMs that is consistent with virtualizing complex commodity operating systems, on shared complex commodity hardware.
{"title":"The Xenon separation VMM: Secure virtualization infrastructure for military clouds","authors":"J. McDermott, B. Montrose, Margery Li, J. Kirby, Myong H. Kang","doi":"10.1109/MILCOM.2012.6415673","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415673","url":null,"abstract":"In conventional military computing, security separation is provided by cryptography, for data in motion and data at rest. Security separation for data under computation is provided by separate hardware. Cloud computing shares hardware for all data under computation, so a new approach to security separation is needed for military clouds. Cryptographic separation of data under computation is not practical with current technology, so the separation must be accomplished by software, i.e. the virtualization infrastructure. The strongest known means of software separation is the separation kernel. Separation kernels are special virtual machine monitors (VMMs) that are small enough and simple enough to be mathematically verified. Unfortunately, strict separation kernels cannot virtualize the complex modern commodity hardware and guest virtual machine (VM) operating systems that are essential to cloud computing. The best alternative to a strict separation kernel is a a separation VMM. A separation VMM relaxes the strict size and simplicity goals of a separation kernel just far enough to be able to support commodity hardware and guest operating systems. Because they address all of the features of commodity hardware, separation VMMs are too large for formal mathematical verification. However, separation VMMs are small enough and simple enough to be completely specified by semiformal means, i.e. they are smaller and simpler than conventional VMMs. A separation VMM has a complete systematic assurance argument that it isolates guest VMs from each other and strongly protects itself from tampering. A separation VMM provides the strongest separation of cloud VMs that is consistent with virtualizing complex commodity operating systems, on shared complex commodity hardware.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"22 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76061332","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415689
P. Elliot, E. Rosario, R. Davis
A multi-use antenna system for integrated communications and navigation capability was developed. A GPS/GNSS/Iridium antenna is co-located with a UHF communications monopole on a handset. The GPS/GNSS/Iridium antenna is a folded Quadrifilar Helix Antenna (QHA) with novel features to improve frequency coverage compared to existing QHA designs. This QHA antenna is co-located concentrically (co-axially) around the UHF monopole which increases the gain of the UHF monopole by several dB over most of the UHF 225-512 MHz band. Co-locating the QHA and monopole also reduces the area needed on the transceiver. The GNSS frequencies covered include modernized GPS (L1, L2, L5), GLONASS, Galileo, and Beidou (Compass), spanning from 1164 to 1300 MHz and 1559 to 1611 MHz. The Iridium communications transmit and receive band (1611-1626 MHz) is also covered, and UHF.
{"title":"Novel Quadrifilar Helix Antenna combining GNSS, Iridium, and a UHF communications monopole","authors":"P. Elliot, E. Rosario, R. Davis","doi":"10.1109/MILCOM.2012.6415689","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415689","url":null,"abstract":"A multi-use antenna system for integrated communications and navigation capability was developed. A GPS/GNSS/Iridium antenna is co-located with a UHF communications monopole on a handset. The GPS/GNSS/Iridium antenna is a folded Quadrifilar Helix Antenna (QHA) with novel features to improve frequency coverage compared to existing QHA designs. This QHA antenna is co-located concentrically (co-axially) around the UHF monopole which increases the gain of the UHF monopole by several dB over most of the UHF 225-512 MHz band. Co-locating the QHA and monopole also reduces the area needed on the transceiver. The GNSS frequencies covered include modernized GPS (L1, L2, L5), GLONASS, Galileo, and Beidou (Compass), spanning from 1164 to 1300 MHz and 1559 to 1611 MHz. The Iridium communications transmit and receive band (1611-1626 MHz) is also covered, and UHF.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"4 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85356956","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}
Pub Date : 2012-10-01DOI: 10.1109/MILCOM.2012.6415874
E. Adebola, O. Olabiyi, A. Annamalai
In this article, we apply two distinct methods to obtain simple closed-form approximations for the average symbol error rate (ASER) performance metric of a broad class of coherent digital modulations in a myriad of fading environments (with/without diversity), which are known to be analytically involved as they require evaluation of the expectation of the Gaussian Q-function and/or its integer powers. In the first approach, we exploit the shifting property of Dirac delta approximations of the Q-function to circumvent the need for integration. In the second approach, we introduce tight exponential-type approximations for the Q-function that directly lead to the development of closed-form expressions for the ASER in terms of only the moment generating function (MGF) of the received signal-to-noise ratio (SNR) random variable. Numerical results reveal that our proposed solutions based on the MGF method are much more versatile and can yield better accuracy compared to our approximations derived via the Dirac delta approximation technique.
{"title":"Some remarks on the Dirac delta function approximation for ASER analysis of digital modulations over fading channels","authors":"E. Adebola, O. Olabiyi, A. Annamalai","doi":"10.1109/MILCOM.2012.6415874","DOIUrl":"https://doi.org/10.1109/MILCOM.2012.6415874","url":null,"abstract":"In this article, we apply two distinct methods to obtain simple closed-form approximations for the average symbol error rate (ASER) performance metric of a broad class of coherent digital modulations in a myriad of fading environments (with/without diversity), which are known to be analytically involved as they require evaluation of the expectation of the Gaussian Q-function and/or its integer powers. In the first approach, we exploit the shifting property of Dirac delta approximations of the Q-function to circumvent the need for integration. In the second approach, we introduce tight exponential-type approximations for the Q-function that directly lead to the development of closed-form expressions for the ASER in terms of only the moment generating function (MGF) of the received signal-to-noise ratio (SNR) random variable. Numerical results reveal that our proposed solutions based on the MGF method are much more versatile and can yield better accuracy compared to our approximations derived via the Dirac delta approximation technique.","PeriodicalId":18720,"journal":{"name":"MILCOM 2012 - 2012 IEEE Military Communications Conference","volume":"135 7 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2012-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88647509","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}
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