Pub Date : 2005-10-17DOI: 10.1109/MILCOM.2005.1605762
J. Acharya, Roy D. Yates, Leonid Razoumov
Systems supporting broadband mobile services over wireless channels suffer from dispersion along time and frequency. Hence transmission by spreading information along both these dimensions leads to diversity gain in each dimension. Motivated by this principle, we propose a generalized two dimensional spreading scheme, in which a symbol is transmitted across several subcarriers with a total power constraint and along each subcarrier it is spread with CDMA codewords. The information theoretic bounds on capacity for this scheme are derived under different assumptions about the channel state information (CSI) available at the transmitter. These are perfect CSI, partial CSI characterized by one bit of channel information per subcarrier and no CSI. The receiver is assumed to have perfect CSI. The optimal codeword and power allocation strategies to achieve these bounds are derived for the single user point to point transmission. The solutions also apply to the cases of synchronous multi-user uplink transmission, or when the receiver schedules transmissions of multiple users. For asynchronous uplink communications, we show that the problem of optimal resource allocation is analytically intractable and instead suggest a heuristic solution, which can be implemented in a distributed manner
{"title":"Two dimensional spreading for dispersive channels","authors":"J. Acharya, Roy D. Yates, Leonid Razoumov","doi":"10.1109/MILCOM.2005.1605762","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605762","url":null,"abstract":"Systems supporting broadband mobile services over wireless channels suffer from dispersion along time and frequency. Hence transmission by spreading information along both these dimensions leads to diversity gain in each dimension. Motivated by this principle, we propose a generalized two dimensional spreading scheme, in which a symbol is transmitted across several subcarriers with a total power constraint and along each subcarrier it is spread with CDMA codewords. The information theoretic bounds on capacity for this scheme are derived under different assumptions about the channel state information (CSI) available at the transmitter. These are perfect CSI, partial CSI characterized by one bit of channel information per subcarrier and no CSI. The receiver is assumed to have perfect CSI. The optimal codeword and power allocation strategies to achieve these bounds are derived for the single user point to point transmission. The solutions also apply to the cases of synchronous multi-user uplink transmission, or when the receiver schedules transmissions of multiple users. For asynchronous uplink communications, we show that the problem of optimal resource allocation is analytically intractable and instead suggest a heuristic solution, which can be implemented in a distributed manner","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131107974","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1605779
J. Padgett
If N users share a wireless channel of capacity R on a time-division basis, the average rate is R/N, but this is not necessarily the apparent or effective rate experienced by the user. If the user is engaged in activities that demand bursts of data followed by inactive periods, such as downloading and reading Web pages, then the channel rate as perceived by the user depends on how long it takes to load the web page following the user's request. This paper develops simple queueing models and a simulation to show how this effective rate depends on R and N, and the parameters of the data traffic. The purpose here is not to provide a rigorous or exhaustive analysis, but rather to develop an initial understanding of the relationship among channel rate, number of active users, idle time, data block size, and the effective rate. These relationships are useful for wireless link design and tradeoff analysis
{"title":"Effective rate per user on shared broadband wireless data channels","authors":"J. Padgett","doi":"10.1109/MILCOM.2005.1605779","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605779","url":null,"abstract":"If N users share a wireless channel of capacity R on a time-division basis, the average rate is R/N, but this is not necessarily the apparent or effective rate experienced by the user. If the user is engaged in activities that demand bursts of data followed by inactive periods, such as downloading and reading Web pages, then the channel rate as perceived by the user depends on how long it takes to load the web page following the user's request. This paper develops simple queueing models and a simulation to show how this effective rate depends on R and N, and the parameters of the data traffic. The purpose here is not to provide a rigorous or exhaustive analysis, but rather to develop an initial understanding of the relationship among channel rate, number of active users, idle time, data block size, and the effective rate. These relationships are useful for wireless link design and tradeoff analysis","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133386373","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1605974
H. El-Damhougy, H. Yousefi'zadeh, D. Lofquist, R. Sackman, J. Crowley
Global information grid (GIG) is becoming a reality with emerging state-of-the-art communication system infrastructure. In this paper, we describe issues facing both global and tactical network managers. We also propose a model for developing a global network management architecture. The main elements of our proposed model include network management (NM) concept of operations (CONOPS), requirement space, technical reference architecture, reference design, and implementation/development framework. We further describe the key areas that an integrated NM CONOPS must address.
{"title":"Hierarchical and federated network management for tactical environments","authors":"H. El-Damhougy, H. Yousefi'zadeh, D. Lofquist, R. Sackman, J. Crowley","doi":"10.1109/MILCOM.2005.1605974","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605974","url":null,"abstract":"Global information grid (GIG) is becoming a reality with emerging state-of-the-art communication system infrastructure. In this paper, we describe issues facing both global and tactical network managers. We also propose a model for developing a global network management architecture. The main elements of our proposed model include network management (NM) concept of operations (CONOPS), requirement space, technical reference architecture, reference design, and implementation/development framework. We further describe the key areas that an integrated NM CONOPS must address.","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133685662","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1606134
J. E. Kerivan, K. Brothers
This paper describes a series of tests designed to attack security software in real time as it provides protection for applications and operating system programs on Microsoft Windows 2000 operating platforms. One security program tested fell into the Intrusion Prevention System (IPS) category of security software. A second security solution provided Anti-Viral protection and the third security program provided Anti-Malware protection for the test systems with a principal focus on Spyware and Adware detection and removal. All security programs were run in a variety of conditions including single mode, where only the security application was running through full integration modes where all security applications were running simultaneously. Security program default configurations were used in all tests. The findings indicate that none of the tested software was capable of defending itself against attacks designed to suspend and unload them from memory. As is shown, the IPS software was more robust than the other two solutions, but was easily compromised and actually created numerous false positives and misinformed the user on the running of the other security software.
本文介绍了针对Microsoft Windows 2000操作平台上的应用程序和操作系统程序提供保护的一系列实时攻击安全软件的测试。测试的一个安全程序属于入侵防御系统(IPS)一类的安全软件。第二个安全解决方案提供反病毒保护，第三个安全程序为测试系统提供反恶意软件保护，主要侧重于间谍软件和广告软件的检测和删除。所有安全程序都在各种条件下运行，包括单一模式，其中只有安全应用程序运行，以及所有安全应用程序同时运行的完全集成模式。所有测试都使用安全程序的默认配置。调查结果表明，没有一款被测试的软件能够抵御旨在将它们从内存中挂起和卸载的攻击。如图所示，IPS软件比其他两种解决方案更健壮，但很容易被攻破，实际上产生了许多误报，并误导用户运行其他安全软件。
{"title":"Self-defending security software","authors":"J. E. Kerivan, K. Brothers","doi":"10.1109/MILCOM.2005.1606134","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1606134","url":null,"abstract":"This paper describes a series of tests designed to attack security software in real time as it provides protection for applications and operating system programs on Microsoft Windows 2000 operating platforms. One security program tested fell into the Intrusion Prevention System (IPS) category of security software. A second security solution provided Anti-Viral protection and the third security program provided Anti-Malware protection for the test systems with a principal focus on Spyware and Adware detection and removal. All security programs were run in a variety of conditions including single mode, where only the security application was running through full integration modes where all security applications were running simultaneously. Security program default configurations were used in all tests. The findings indicate that none of the tested software was capable of defending itself against attacks designed to suspend and unload them from memory. As is shown, the IPS software was more robust than the other two solutions, but was easily compromised and actually created numerous false positives and misinformed the user on the running of the other security software.","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"181 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133341346","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1605935
T. Carrico, F. Perich
We describe ActiveEdge, a platform that leverages the grid computing paradigm for transforming existing data sources into grid-based services. To augment the power of grid computing, ActiveEdge embeds cognitive intelligence for achieving a high degree of automation, effective information management, and near real-time situational reasoning. ActiveEdge also provides users and organizations that reside in widely different physical locations and have disparate computing resources with a customizable solution for managing and processing information reliably, seamlessly, and efficiently
{"title":"Cognitive situation monitoring and awareness of grid systems","authors":"T. Carrico, F. Perich","doi":"10.1109/MILCOM.2005.1605935","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605935","url":null,"abstract":"We describe ActiveEdge, a platform that leverages the grid computing paradigm for transforming existing data sources into grid-based services. To augment the power of grid computing, ActiveEdge embeds cognitive intelligence for achieving a high degree of automation, effective information management, and near real-time situational reasoning. ActiveEdge also provides users and organizations that reside in widely different physical locations and have disparate computing resources with a customizable solution for managing and processing information reliably, seamlessly, and efficiently","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132137594","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1605763
Haibin Huang, H. Ge
In this work, a channel estimation scheme is introduced to single carrier block transmission systems. Compared to the conventional method, the proposed scheme has similar estimation accuracy but with higher transmission efficiency and lower complexity. Under the anti-polar constellation constraint, the optimal training sequence design is studied. Furthermore, a simplified minimum mean square error (MMSE) block equalizer is derived. Numerical results show that the proposed equalizer outperforms the conventional method
{"title":"Low complexity channel estimation and equalization for block transmission systems","authors":"Haibin Huang, H. Ge","doi":"10.1109/MILCOM.2005.1605763","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605763","url":null,"abstract":"In this work, a channel estimation scheme is introduced to single carrier block transmission systems. Compared to the conventional method, the proposed scheme has similar estimation accuracy but with higher transmission efficiency and lower complexity. Under the anti-polar constellation constraint, the optimal training sequence design is studied. Furthermore, a simplified minimum mean square error (MMSE) block equalizer is derived. Numerical results show that the proposed equalizer outperforms the conventional method","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"5 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132154152","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1605844
C. Esli, H. Deliç
Performance of orthogonal frequency-division multiple access (OFDMA) system equipped with space-frequency coding (SFC) is considered in the presence of partial band noise jamming (PBNJ). The bit error probability (BEP) expressions are derived for OFDMA with and without SFC in a frequency-selective fading environment. Analysis and simulation results show that SFC increases the resistance of OFDMA against the PBNJ and reduces the BEP considerably
{"title":"Space-frequency coding in the presence of partial band noise jamming","authors":"C. Esli, H. Deliç","doi":"10.1109/MILCOM.2005.1605844","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605844","url":null,"abstract":"Performance of orthogonal frequency-division multiple access (OFDMA) system equipped with space-frequency coding (SFC) is considered in the presence of partial band noise jamming (PBNJ). The bit error probability (BEP) expressions are derived for OFDMA with and without SFC in a frequency-selective fading environment. Analysis and simulation results show that SFC increases the resistance of OFDMA against the PBNJ and reduces the BEP considerably","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133241802","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1605827
P.J. Oleski, M. Thaduri, S. Bharj
Satellites require timely tracking, telemetry, and command (TT&C) for payload operation. The ground antenna is one of the key elements that enable satellite control and payload operations. To support the operation of a large number of satellites at various orbits, operators need a network of antennas distributed around the globe, such as the air force satellite control network (AFSCN), to contact satellites at a predetermined time and location. Currently, they use large mechanically steered parabolic dishes to provide hemispherical coverage and simultaneous transmit (Tx) and receive (Rx) capabilities in support of Department of Defense (DoD) satellite operations (SATOPS) network designers used reflector antennas because of relatively low acquisition cost. The current reflector antennas used to support satellite operations are approximately 10 m in diameter and are susceptible to single point failure and long downtime for repair and maintenance. S-Band component technology provided by the cell phone industry allows an affordable electronically scanned antenna (ESA). Current SATOPS require a more efficient and flexible antenna system. The ESA can offer superior performance, operability, adaptability and maintainability for satellite operation. This paper presents the design of a TR module that can provide one transmit (Tx) and two receive (Rx) links to a satellite. The TR module is part of a dome shaped antenna that could provide multiple simultaneous ground to satellite links. This geodome antenna provide multiples simultaneous operations with pointing and acquisition taking seconds. One dome antenna can replace the capability of three AFSCN parabolic dishes. The next generation low cost TR module developed by the AFRL/Information Grid Division (IFG) and Princeton Microwave Technology Inc. for the next generation of the AF Satellite Control Network (AFSCN). The TR module differs from previous modules in Ref S.S. Bharj et al, (2000) and P.J. Oleski et al, (2004) in that it consists of a single Tx channel capable of 33 dBm of output power and two Rx channels with a gain of 30 dB per channel In addition, beam switching and on board digital control has been implemented where the Tx and Rx channels provide four-bit phase shift. In addition to the control functions, built-in test (BIT) circuits monitors the health and status of the RF devices. This function utilizes a low-power micro-controller to output digital data for each of the power and low noise amplifiers, via A/D converters. The bandwidth of the TR module has been designed to cover both the unified S-Band (USB) and satellite ground link subsystem (SGLS). The TR functions are combined at the output via a ceramic resonator diplexer comprised of a band pass-band stop filter. The control of the TR module is conducted via a single programmable logic device (PLD) controller through a DAQ computer interface. The TR module has been designed to meet the cost objective for a dome antenna with approximate
{"title":"Transmit receive module for S-band electronically scanned antenna with on board digital control, health monitoring and telemetry","authors":"P.J. Oleski, M. Thaduri, S. Bharj","doi":"10.1109/MILCOM.2005.1605827","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605827","url":null,"abstract":"Satellites require timely tracking, telemetry, and command (TT&C) for payload operation. The ground antenna is one of the key elements that enable satellite control and payload operations. To support the operation of a large number of satellites at various orbits, operators need a network of antennas distributed around the globe, such as the air force satellite control network (AFSCN), to contact satellites at a predetermined time and location. Currently, they use large mechanically steered parabolic dishes to provide hemispherical coverage and simultaneous transmit (Tx) and receive (Rx) capabilities in support of Department of Defense (DoD) satellite operations (SATOPS) network designers used reflector antennas because of relatively low acquisition cost. The current reflector antennas used to support satellite operations are approximately 10 m in diameter and are susceptible to single point failure and long downtime for repair and maintenance. S-Band component technology provided by the cell phone industry allows an affordable electronically scanned antenna (ESA). Current SATOPS require a more efficient and flexible antenna system. The ESA can offer superior performance, operability, adaptability and maintainability for satellite operation. This paper presents the design of a TR module that can provide one transmit (Tx) and two receive (Rx) links to a satellite. The TR module is part of a dome shaped antenna that could provide multiple simultaneous ground to satellite links. This geodome antenna provide multiples simultaneous operations with pointing and acquisition taking seconds. One dome antenna can replace the capability of three AFSCN parabolic dishes. The next generation low cost TR module developed by the AFRL/Information Grid Division (IFG) and Princeton Microwave Technology Inc. for the next generation of the AF Satellite Control Network (AFSCN). The TR module differs from previous modules in Ref S.S. Bharj et al, (2000) and P.J. Oleski et al, (2004) in that it consists of a single Tx channel capable of 33 dBm of output power and two Rx channels with a gain of 30 dB per channel In addition, beam switching and on board digital control has been implemented where the Tx and Rx channels provide four-bit phase shift. In addition to the control functions, built-in test (BIT) circuits monitors the health and status of the RF devices. This function utilizes a low-power micro-controller to output digital data for each of the power and low noise amplifiers, via A/D converters. The bandwidth of the TR module has been designed to cover both the unified S-Band (USB) and satellite ground link subsystem (SGLS). The TR functions are combined at the output via a ceramic resonator diplexer comprised of a band pass-band stop filter. The control of the TR module is conducted via a single programmable logic device (PLD) controller through a DAQ computer interface. The TR module has been designed to meet the cost objective for a dome antenna with approximate","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134499342","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1605686
Dandan Wang, U. Tureli
Multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) can be used to boost up capacity for broadband wireless communication. However, it is not easy to generalize these techniques to broadband ad hoc networks since existing medium access control (MAC) schemes are designed to accept only one user in a neighborhood. With MIMO-OFDM, multiple nodes can coexist in the same neighborhood. A transceiver architecture merging MIMO-OFDM and with a novel MAC scheme-multiple antennas receiver initiated busy tone medium access (MARI-BTMA) is proposed in this paper. MARI-BTMA is based on receiver initiated busy tone medium access (RI-BTMA) and uses multiple out of band busy-tones to notify the nodes about the number of users in the system and avoid collision on the same channel. To improve the performance at low traffic loads, an adaptive MARI-BTMA is also proposed. In this paper, both theoretical and numerical analysis of the throughput and delay are presented. Analysis and simulation results show the improved performance of MARI-BTMA compared with RI-BTMA and carrier sensing medium access/collision avoidance (CSMA/CA)
多输入多输出(MIMO)和正交频分复用(OFDM)可以提高宽带无线通信的容量。然而，由于现有的介质访问控制(MAC)方案被设计为只接受一个邻居中的一个用户，因此将这些技术推广到宽带自组织网络并不容易。使用MIMO-OFDM，多个节点可以共存于同一邻域。提出了一种融合MIMO-OFDM和一种新颖的MAC方案-多天线接收机发起的忙音介质接入(MARI-BTMA)的收发机架构。MARI-BTMA基于RI-BTMA (receiver initiated busy tone medium access)，利用多个带外忙音通知各节点系统内的用户数，避免同一信道上的冲突。为了提高低流量负载下的性能，还提出了一种自适应MARI-BTMA。本文对吞吐量和延迟进行了理论和数值分析。分析和仿真结果表明，与RI-BTMA和载波感知介质接入/避碰(CSMA/CA)相比，MARI-BTMA的性能有所提高。
{"title":"MIMO-OFDM and MAC design for broadband ad hoc network","authors":"Dandan Wang, U. Tureli","doi":"10.1109/MILCOM.2005.1605686","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1605686","url":null,"abstract":"Multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) can be used to boost up capacity for broadband wireless communication. However, it is not easy to generalize these techniques to broadband ad hoc networks since existing medium access control (MAC) schemes are designed to accept only one user in a neighborhood. With MIMO-OFDM, multiple nodes can coexist in the same neighborhood. A transceiver architecture merging MIMO-OFDM and with a novel MAC scheme-multiple antennas receiver initiated busy tone medium access (MARI-BTMA) is proposed in this paper. MARI-BTMA is based on receiver initiated busy tone medium access (RI-BTMA) and uses multiple out of band busy-tones to notify the nodes about the number of users in the system and avoid collision on the same channel. To improve the performance at low traffic loads, an adaptive MARI-BTMA is also proposed. In this paper, both theoretical and numerical analysis of the throughput and delay are presented. Analysis and simulation results show the improved performance of MARI-BTMA compared with RI-BTMA and carrier sensing medium access/collision avoidance (CSMA/CA)","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127386044","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 : 2005-10-17DOI: 10.1109/MILCOM.2005.1606083
Yi Sun, Junmin Shi
This paper considers a large CDMA random access system where a number of users randomly access a basestation through a common CDMA channel. The number of users and spreading gain tend to infinity with their ratio convergent to a constant. An approach is proposed to exploitation of retransmission diversity. Performance of three systems is analyzed: (i) random spreading with exploitation of retransmission diversity; (ii) randomly selected but fixed spreading for each packet with exploitation of retransmission diversity; and (iii) random spreading without exploitation of retransmission diversity. Lower bounds on the limit SIRs of the first two systems and the exact limit SIR of the third system are obtained. User throughput, packet delay, transmission time, and waiting time as well as spectral efficiency in the limit system are obtained as functions of medium access control (MAC). The analytical results are confirmed by simulations. It is shown that out of many system settings, (i) is the most favorable in terms of maximization of spectral efficiency and simplicity of MAC.
{"title":"Large CDMA random access systems with exploitation of retransmission diversity","authors":"Yi Sun, Junmin Shi","doi":"10.1109/MILCOM.2005.1606083","DOIUrl":"https://doi.org/10.1109/MILCOM.2005.1606083","url":null,"abstract":"This paper considers a large CDMA random access system where a number of users randomly access a basestation through a common CDMA channel. The number of users and spreading gain tend to infinity with their ratio convergent to a constant. An approach is proposed to exploitation of retransmission diversity. Performance of three systems is analyzed: (i) random spreading with exploitation of retransmission diversity; (ii) randomly selected but fixed spreading for each packet with exploitation of retransmission diversity; and (iii) random spreading without exploitation of retransmission diversity. Lower bounds on the limit SIRs of the first two systems and the exact limit SIR of the third system are obtained. User throughput, packet delay, transmission time, and waiting time as well as spectral efficiency in the limit system are obtained as functions of medium access control (MAC). The analytical results are confirmed by simulations. It is shown that out of many system settings, (i) is the most favorable in terms of maximization of spectral efficiency and simplicity of MAC.","PeriodicalId":223742,"journal":{"name":"MILCOM 2005 - 2005 IEEE Military Communications Conference","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115418595","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：