Pub Date : 2001-10-28DOI: 10.1109/MILCOM.2001.986037
Min Dong, L. Tong
The problem of training symbol placement for the estimation of a block-fading channel is first considered. The channel is frequency selective with correlated random taps. The Cramer-Rao bound (CRB) on the mean square error (MSE) of channel estimators is derived and minimized with respect to the pilot symbols and their placement. It is shown that, among all orthogonal pilot sequence placements, the minimum CRB is achieved by concentrating pilot and data powers in the middle of the packet. The placement of training for tracking time-varying channels is then addressed. Both flat and frequency selective fading environments are considered. We optimized training by minimizing the MSE of channel estimators chosen from optimal and sub-optimal tracking algorithms.
{"title":"Optimal placement of training for channel estimation and tracking","authors":"Min Dong, L. Tong","doi":"10.1109/MILCOM.2001.986037","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986037","url":null,"abstract":"The problem of training symbol placement for the estimation of a block-fading channel is first considered. The channel is frequency selective with correlated random taps. The Cramer-Rao bound (CRB) on the mean square error (MSE) of channel estimators is derived and minimized with respect to the pilot symbols and their placement. It is shown that, among all orthogonal pilot sequence placements, the minimum CRB is achieved by concentrating pilot and data powers in the middle of the packet. The placement of training for tracking time-varying channels is then addressed. Both flat and frequency selective fading environments are considered. We optimized training by minimizing the MSE of channel estimators chosen from optimal and sub-optimal tracking algorithms.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131811223","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.985759
L. Westbrook, T. Calladene, I. Berry, N. Briscombe
Tactical military SATCOMs require a sophisticated balance between efficiency and resilience. Ideally, this balance needs to be flexible and dynamic, so as to adapt as demands (and threats) ebb and flow. Automation is seen as the key to providing the flexibility to migrate SATCOM band plans between rapidly evolving scenarios. Efficiency and revenue maximisation are often the key drivers in commercial satellite systems, nevertheless carrier frequency allocation techniques developed for civilian systems can be usefully employed in military systems, provided optimisation is extended to address resilience and support flexibility. Key factors in optimising frequency plans in multi-satellite, multi-beam, multi-terminal, multi-modulation systems are frequency re-use, compliance with satellite and ground station regulation and co-ordination agreements and, critically, the control (or mitigation) of intermodulation products. Significant differences between military and civilian systems are the likelihood of electronic attack and the widespread use of spread-spectrum (particularly frequency hopped) systems, which typically trade spectral efficiency for increased robustness and reduced probability of detection. We describe carrier frequency assignment approaches for SATCOM systems. Techniques studied include the use of meta-heuristic algorithms, such as genetic algorithms and tabu search, and quasi intermodulation-free schemes based on Golomb rulers, as well as conventional heuristic approaches such as variants of the insertion/deletion method.
{"title":"Carrier frequency allocation in FDMA military SATCOMs","authors":"L. Westbrook, T. Calladene, I. Berry, N. Briscombe","doi":"10.1109/MILCOM.2001.985759","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985759","url":null,"abstract":"Tactical military SATCOMs require a sophisticated balance between efficiency and resilience. Ideally, this balance needs to be flexible and dynamic, so as to adapt as demands (and threats) ebb and flow. Automation is seen as the key to providing the flexibility to migrate SATCOM band plans between rapidly evolving scenarios. Efficiency and revenue maximisation are often the key drivers in commercial satellite systems, nevertheless carrier frequency allocation techniques developed for civilian systems can be usefully employed in military systems, provided optimisation is extended to address resilience and support flexibility. Key factors in optimising frequency plans in multi-satellite, multi-beam, multi-terminal, multi-modulation systems are frequency re-use, compliance with satellite and ground station regulation and co-ordination agreements and, critically, the control (or mitigation) of intermodulation products. Significant differences between military and civilian systems are the likelihood of electronic attack and the widespread use of spread-spectrum (particularly frequency hopped) systems, which typically trade spectral efficiency for increased robustness and reduced probability of detection. We describe carrier frequency assignment approaches for SATCOM systems. Techniques studied include the use of meta-heuristic algorithms, such as genetic algorithms and tabu search, and quasi intermodulation-free schemes based on Golomb rulers, as well as conventional heuristic approaches such as variants of the insertion/deletion method.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116621594","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.986031
J.J. Poklemba, G. Mitchell, R. F. Smith
It is well-known that conventional double-sideband (DSB) transmission is not bandwidth-efficient; and historically, in applications where bandwidth is relatively scarce, analog single-sideband (SSB) and vestigial-sideband (VSB) techniques have been used. Previously, high-definition television (HDTV) has opted to send its images digitally-employing multi-level, amplitude-shift-keyed, VSB transmission. This paper extends and broadens the digital VSB transmission concept by demonstrating the utility of quadrature-VSB (QVSB), where two independent data streams are placed on sine and cosine VSB carriers-effectively doubling the bandwidth-efficiency, at the expense of inducing a controlled form of intersymbol-interference (ISI). Classes of minimal ISI filtering families for QVSB are defined, which are more restrictive than Nyquist data shaping. Also, it is demonstrated that m-ary QVSB typically achieves the same capacity as m/sup 2/-ary QDSB, but requires significantly less E/sub b//N/sub o/.
{"title":"QVSB data transmission","authors":"J.J. Poklemba, G. Mitchell, R. F. Smith","doi":"10.1109/MILCOM.2001.986031","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986031","url":null,"abstract":"It is well-known that conventional double-sideband (DSB) transmission is not bandwidth-efficient; and historically, in applications where bandwidth is relatively scarce, analog single-sideband (SSB) and vestigial-sideband (VSB) techniques have been used. Previously, high-definition television (HDTV) has opted to send its images digitally-employing multi-level, amplitude-shift-keyed, VSB transmission. This paper extends and broadens the digital VSB transmission concept by demonstrating the utility of quadrature-VSB (QVSB), where two independent data streams are placed on sine and cosine VSB carriers-effectively doubling the bandwidth-efficiency, at the expense of inducing a controlled form of intersymbol-interference (ISI). Classes of minimal ISI filtering families for QVSB are defined, which are more restrictive than Nyquist data shaping. Also, it is demonstrated that m-ary QVSB typically achieves the same capacity as m/sup 2/-ary QDSB, but requires significantly less E/sub b//N/sub o/.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133775155","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.986005
Wanshi Chen, U. Mitra
Several reduced-rank detection schemes for direct-sequence code-division multiple access (DS-CDMA) communication systems are compared. After the simplification of the auxiliary vector filtering (AVF) algorithm (Pados and Batalama 1999), it is shown that the AVF algorithm is equivalent to the multistage Wiener filtering (MWF) algorithm of Honig and Goldstein. Furthermore, these schemes can be shown to be equivalent to the multistage linear receiver scheme based on the Cayley Hamilton theorem. The analysis of the reduced rank techniques is extended to multipath fading channels. In particular, a modified reduced rank etection scheme is proposed which outperforms an isolated path combining strategy. In addition, the output signal-to-interference ratio for the noncoherent equal gain combining linear receiver is analyzed to facilitate the study of the tracking behavior of the reduced rank receivers.
对直接序列码分多址(DS-CDMA)通信系统的几种降阶检测方案进行了比较。在对辅助向量滤波(AVF)算法(Pados and Batalama 1999)进行简化后，表明AVF算法等价于Honig和Goldstein的多阶段维纳滤波(MWF)算法。此外，基于Cayley Hamilton定理，可以证明这些方案等价于多级线性接收机方案。将降阶技术的分析推广到多径衰落信道。特别提出了一种改进的降阶选举方案，该方案优于孤立路径组合策略。此外，分析了非相干等增益组合线性接收机的输出信干扰比，便于研究降阶接收机的跟踪行为。
{"title":"Reduced-rank detection schemes for DS-CDMA communication systems","authors":"Wanshi Chen, U. Mitra","doi":"10.1109/MILCOM.2001.986005","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986005","url":null,"abstract":"Several reduced-rank detection schemes for direct-sequence code-division multiple access (DS-CDMA) communication systems are compared. After the simplification of the auxiliary vector filtering (AVF) algorithm (Pados and Batalama 1999), it is shown that the AVF algorithm is equivalent to the multistage Wiener filtering (MWF) algorithm of Honig and Goldstein. Furthermore, these schemes can be shown to be equivalent to the multistage linear receiver scheme based on the Cayley Hamilton theorem. The analysis of the reduced rank techniques is extended to multipath fading channels. In particular, a modified reduced rank etection scheme is proposed which outperforms an isolated path combining strategy. In addition, the output signal-to-interference ratio for the noncoherent equal gain combining linear receiver is analyzed to facilitate the study of the tracking behavior of the reduced rank receivers.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129717398","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.985756
A. Swami, Brian M. Sadler, J. Turner
Ultra-wideband (UWB) signals will encounter many interference sources, primarily from relatively narrowband (NB) systems. In addition., UWB signals will also affect a large number of NB radios; of critical importance is the potential interference with GPS, E-911, and navigation bands, as well as cellular bands. There is a rich and growing literature on UWB radios; however, issues related to interference measurements have only been partially addressed. Here, we assess the interference caused by UWB signals via analysis and simulations. Analytical results include the aggregate effect of spatially distributed UWB radios on a receiver, and theoretical BER expressions.
{"title":"On the coexistence of ultra-wideband and narrowband radio systems","authors":"A. Swami, Brian M. Sadler, J. Turner","doi":"10.1109/MILCOM.2001.985756","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985756","url":null,"abstract":"Ultra-wideband (UWB) signals will encounter many interference sources, primarily from relatively narrowband (NB) systems. In addition., UWB signals will also affect a large number of NB radios; of critical importance is the potential interference with GPS, E-911, and navigation bands, as well as cellular bands. There is a rich and growing literature on UWB radios; however, issues related to interference measurements have only been partially addressed. Here, we assess the interference caused by UWB signals via analysis and simulations. Analytical results include the aggregate effect of spatially distributed UWB radios on a receiver, and theoretical BER expressions.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129951924","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.985831
W. Burakowski, A. Beben, P. Pyda
This paper evaluates the multiplexing gain we can reach on ATM radio-relay link, used for the purpose of inter-node transmission in the tactical networks. This link has limited capacity, e.g. from 2 up to 8 Mbps, and it can cause that profit of using ATM can be much less than expected. Note that ATM technology was mainly designed for integrated networks offering QoS (quality of service) guarantees. Additionally, a high profit of cell multiplexing was expected by using dynamic slot-to-cell allocation. The multiplexing gain in ATM tactical links is estimated under traffic conditions adequate for tactical networks. It means that the network should serve cell traffic generated by applications appropriate for modern command and control systems, e.g. based on transferring voice, data and video signals. For these applications, a level of the QoS is required. Therefore, only these ATM network services can be considered which guarantee appropriate QoS, at both the cell and call level, like CBR and VBR. Numerical results showing limitations of getting reasonable multiplexing gain in an ATM tactical link are included.
{"title":"Estimation of multiplexing gain in ATM tactical links","authors":"W. Burakowski, A. Beben, P. Pyda","doi":"10.1109/MILCOM.2001.985831","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985831","url":null,"abstract":"This paper evaluates the multiplexing gain we can reach on ATM radio-relay link, used for the purpose of inter-node transmission in the tactical networks. This link has limited capacity, e.g. from 2 up to 8 Mbps, and it can cause that profit of using ATM can be much less than expected. Note that ATM technology was mainly designed for integrated networks offering QoS (quality of service) guarantees. Additionally, a high profit of cell multiplexing was expected by using dynamic slot-to-cell allocation. The multiplexing gain in ATM tactical links is estimated under traffic conditions adequate for tactical networks. It means that the network should serve cell traffic generated by applications appropriate for modern command and control systems, e.g. based on transferring voice, data and video signals. For these applications, a level of the QoS is required. Therefore, only these ATM network services can be considered which guarantee appropriate QoS, at both the cell and call level, like CBR and VBR. Numerical results showing limitations of getting reasonable multiplexing gain in an ATM tactical link are included.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129985596","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.985764
N. Ikram
In a network, identification of any user is a vital requirement before one is accorded access to the network-shared information bank or database. The database or information may itself either be encrypted or in plain language. There are various techniques, which offer this service through cryptographic techniques as well as through non-cryptographic means, each with its own attributes This paper presents a scheme which uses the identification (ID) based cryptosystem (Shamir, 1984), based on the concept of public key cryptosystem. However, the scheme works on a carefully selected elliptic curve (EC), itself defined on a binary finite field. The finite field so chosen is F/sub 2//sup 215/. The elliptic curve over which the scheme works has been self-generated and those available in the public domain have not been employed. The new scheme offers highly secure underlying cryptosystem and strong challenge-response type of protocol, ensuring complete user trust.
{"title":"Cryptographic identification of users over network","authors":"N. Ikram","doi":"10.1109/MILCOM.2001.985764","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985764","url":null,"abstract":"In a network, identification of any user is a vital requirement before one is accorded access to the network-shared information bank or database. The database or information may itself either be encrypted or in plain language. There are various techniques, which offer this service through cryptographic techniques as well as through non-cryptographic means, each with its own attributes This paper presents a scheme which uses the identification (ID) based cryptosystem (Shamir, 1984), based on the concept of public key cryptosystem. However, the scheme works on a carefully selected elliptic curve (EC), itself defined on a binary finite field. The finite field so chosen is F/sub 2//sup 215/. The elliptic curve over which the scheme works has been self-generated and those available in the public domain have not been employed. The new scheme offers highly secure underlying cryptosystem and strong challenge-response type of protocol, ensuring complete user trust.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130808351","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.986093
V. A. Nguyen, P. Wan, O. Frieder
In a previous work (see Nguyen, V.A. et al., IEEE Vehicular Technology Conference, 2001), we presented a novel channel alternation and rotation (CAR) scheme that coordinates channel assignment with antenna directivity. In CAR, each cell type is allocated an extra channel set that provides the network designer the flexibility to alternate and rotate channels according to a nearest front lobe interference avoidance strategy in order to enhance the cochannel interference ratio (C/I). CAR relaxes the constraints assumed in conventional reuse plans to allow deployment of smaller, unconventional reuse cluster sizes based on C/I requirements, thus increasing frequency reuse efficiency. We present a new reuse plan in which 2 extra channel sets are allocated to each cell type and assigned according to CAR strategy. This reuse plan, referred to as 2/spl times/(3+2), increases channel capacity by 20% in comparison with the conventional 4/spl times/3 reuse plan which still provides signals above the minimum acceptable C/I margin. The 2/spl times/(3+2) reuse plan is simple and can be implemented without costs.
{"title":"A modified directional frequency reuse plan based on channel alternation and rotation","authors":"V. A. Nguyen, P. Wan, O. Frieder","doi":"10.1109/MILCOM.2001.986093","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986093","url":null,"abstract":"In a previous work (see Nguyen, V.A. et al., IEEE Vehicular Technology Conference, 2001), we presented a novel channel alternation and rotation (CAR) scheme that coordinates channel assignment with antenna directivity. In CAR, each cell type is allocated an extra channel set that provides the network designer the flexibility to alternate and rotate channels according to a nearest front lobe interference avoidance strategy in order to enhance the cochannel interference ratio (C/I). CAR relaxes the constraints assumed in conventional reuse plans to allow deployment of smaller, unconventional reuse cluster sizes based on C/I requirements, thus increasing frequency reuse efficiency. We present a new reuse plan in which 2 extra channel sets are allocated to each cell type and assigned according to CAR strategy. This reuse plan, referred to as 2/spl times/(3+2), increases channel capacity by 20% in comparison with the conventional 4/spl times/3 reuse plan which still provides signals above the minimum acceptable C/I margin. The 2/spl times/(3+2) reuse plan is simple and can be implemented without costs.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134049875","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.985849
W. J. Wilson
Layering communications systems (for better horizontal integration and to foster interoperability) is central to the Global Grid architecture. Accordingly, it is important to show how legacy systems can be layered in order to direct future development efforts toward achieving greater compatibility with the Global Grid. This paper assesses whether the Link 16 legacy system can be layered within a Global Grid model that has been developed with military requirements in mind. This model is slightly different from the standard OSI 7-layer one and has the following 7 layers: mission, application, service, transport, network, link and physical. Two approaches to layering are considered. First, in a general way,the feasibility is assessed of layering the entire communications process at every level of the protocol stack. Each layer is examined to see if the different functions can be naturally separated into distinct sublayers. This approach emphasizes the desirability of being able to upgrade system performance by replacing one layer at a time without altering other layers. The second approach is to consider the layering potential of systems in terms of their compatibility with the emerging Global Grid. The main thrust of these concepts is that all systems that are part of the Global Grid should be compatible with its transport and network layers (i.e., TCP/IP and/or some variants). Link 16 is a prime example of a "stovepipe" system, designed to maximize performance in a particular tactical environment with high levels of jamming. Since it was designed before layering principles were in wide use, it presents certain difficulties to the layering process.
{"title":"Applying layering principles to legacy systems: Link 16 as a case study","authors":"W. J. Wilson","doi":"10.1109/MILCOM.2001.985849","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985849","url":null,"abstract":"Layering communications systems (for better horizontal integration and to foster interoperability) is central to the Global Grid architecture. Accordingly, it is important to show how legacy systems can be layered in order to direct future development efforts toward achieving greater compatibility with the Global Grid. This paper assesses whether the Link 16 legacy system can be layered within a Global Grid model that has been developed with military requirements in mind. This model is slightly different from the standard OSI 7-layer one and has the following 7 layers: mission, application, service, transport, network, link and physical. Two approaches to layering are considered. First, in a general way,the feasibility is assessed of layering the entire communications process at every level of the protocol stack. Each layer is examined to see if the different functions can be naturally separated into distinct sublayers. This approach emphasizes the desirability of being able to upgrade system performance by replacing one layer at a time without altering other layers. The second approach is to consider the layering potential of systems in terms of their compatibility with the emerging Global Grid. The main thrust of these concepts is that all systems that are part of the Global Grid should be compatible with its transport and network layers (i.e., TCP/IP and/or some variants). Link 16 is a prime example of a \"stovepipe\" system, designed to maximize performance in a particular tactical environment with high levels of jamming. Since it was designed before layering principles were in wide use, it presents certain difficulties to the layering process.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134147044","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 : 2001-10-28DOI: 10.1109/MILCOM.2001.985804
M. Gerla, S.S. Lee, G. Reali, D. D. Sorte
Two types of call admission strategies have been proposed for real time support in the Internet: per flow, reservation (i.e., RSVP) based, and measurement based. We evaluate these strategies for a video streaming application. We use a simulation environment (based on a Parsec platform) which supports DiffServ tools as well as QoS routing. In our experiments, we compare the performance of RA-CAC with M-CAC. We show that the selection between these alternatives is influenced by tradeoffs between throughput and delay performance; and that different classes of users may opt for one or the other technique. We also consider a hybrid situation in which both RA-CAC and M-CAC coexist in the network and are reciprocally "protected" by a weighted fair queueing (WFQ) trunk scheduler. A key enabling technology for the M-CAC scheme is QoS routing. We use Q-OSPF not only to find paths that satisfy the quality constraints (delay and bandwidths) but also to advertise current traffic, delay and available bandwidth on all network links. We also use leaky buckets for shaping and policing. Leaky bucket parameters are selected as a function of effective bandwidth, buffer space and end-to-end delay bound. If the traffic (after shaping and policing) conforms to the negotiated traffic profile, and the effective resources are allocated to the connection, the packets are guaranteed delivery within a given worst-case delay bound. In our experiments we verify that when bandwidth and buffers are explicitly allocated (with RA-CAC), the delay bounds are satisfied. The same is not true for M-CAC, where only a statistical allocation is carried out.
{"title":"Performance of different call admission schemes in a QoS Diffserv domain","authors":"M. Gerla, S.S. Lee, G. Reali, D. D. Sorte","doi":"10.1109/MILCOM.2001.985804","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985804","url":null,"abstract":"Two types of call admission strategies have been proposed for real time support in the Internet: per flow, reservation (i.e., RSVP) based, and measurement based. We evaluate these strategies for a video streaming application. We use a simulation environment (based on a Parsec platform) which supports DiffServ tools as well as QoS routing. In our experiments, we compare the performance of RA-CAC with M-CAC. We show that the selection between these alternatives is influenced by tradeoffs between throughput and delay performance; and that different classes of users may opt for one or the other technique. We also consider a hybrid situation in which both RA-CAC and M-CAC coexist in the network and are reciprocally \"protected\" by a weighted fair queueing (WFQ) trunk scheduler. A key enabling technology for the M-CAC scheme is QoS routing. We use Q-OSPF not only to find paths that satisfy the quality constraints (delay and bandwidths) but also to advertise current traffic, delay and available bandwidth on all network links. We also use leaky buckets for shaping and policing. Leaky bucket parameters are selected as a function of effective bandwidth, buffer space and end-to-end delay bound. If the traffic (after shaping and policing) conforms to the negotiated traffic profile, and the effective resources are allocated to the connection, the packets are guaranteed delivery within a given worst-case delay bound. In our experiments we verify that when bandwidth and buffers are explicitly allocated (with RA-CAC), the delay bounds are satisfied. The same is not true for M-CAC, where only a statistical allocation is carried out.","PeriodicalId":136537,"journal":{"name":"2001 MILCOM Proceedings Communications for Network-Centric Operations: Creating the Information Force (Cat. No.01CH37277)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2001-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132580064","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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