Pub Date : 2001-12-01DOI: 10.1109/MILCOM.2001.986010
P. Spasojevic, Xiaodong Wang
We study several existing and new techniques for robust multiuser detection in the presence of alpha stable ambient noise. These methods are based on minimizing a certain cost function (e.g., the Huber penalty function) over a discrete set of candidate user bit vectors. The candidate vectors are either obtained by quantizing the continuous minimizers or based on the slowest-descent approach. Simulation results show that the new techniques offer substantial performance and convergence rate improvement over the recently proposed robust multiuser detectors, with little attendant increase in computational complexity. Furthermore, performance sensitivity on the parameter alpha of the noise distribution is low.
{"title":"Multi-user detection in alpha stable noise","authors":"P. Spasojevic, Xiaodong Wang","doi":"10.1109/MILCOM.2001.986010","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986010","url":null,"abstract":"We study several existing and new techniques for robust multiuser detection in the presence of alpha stable ambient noise. These methods are based on minimizing a certain cost function (e.g., the Huber penalty function) over a discrete set of candidate user bit vectors. The candidate vectors are either obtained by quantizing the continuous minimizers or based on the slowest-descent approach. Simulation results show that the new techniques offer substantial performance and convergence rate improvement over the recently proposed robust multiuser detectors, with little attendant increase in computational complexity. Furthermore, performance sensitivity on the parameter alpha of the noise distribution is low.","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":"2001-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126254988","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.2001.986050
Sung-Hoon Moon, D. Han, Myoung-Je Cho
This paper proposes a transform-domain partially adaptive beamformer to reduce the computational complexity of conventional transform-domain beamformers, After transforming the input signals, the proposed beamformer adapts only those parts of the weights that correspond to the transformed coefficients expected to contain interference by using the cell averaging constant false alarm rate (CA-CFAR) processor. The false alarm rate of the CA-CFAR processor is also changed adaptively according to the variation of output power.
{"title":"Two-dimensional transform-domain partially adaptive beamformer","authors":"Sung-Hoon Moon, D. Han, Myoung-Je Cho","doi":"10.1109/MILCOM.2001.986050","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986050","url":null,"abstract":"This paper proposes a transform-domain partially adaptive beamformer to reduce the computational complexity of conventional transform-domain beamformers, After transforming the input signals, the proposed beamformer adapts only those parts of the weights that correspond to the transformed coefficients expected to contain interference by using the cell averaging constant false alarm rate (CA-CFAR) processor. The false alarm rate of the CA-CFAR processor is also changed adaptively according to the variation of output power.","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":"121347244","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.2001.985944
T.E. Ioakimidis, R. Wexler
The US Army has a requirement for long range communications to lower echelon tactical operations centers (TOCs) on-the-move (OTM). Current terrestrial radios are severely range-limited. The MITRE mission oriented investigation and experimentation (MOIE) project calls for the design and prototyping of an affordable satellite communications (SATCOM) terminal. The platform stabilization subsystem is a key component of the MITRE program. We propose a new hybrid-tracking scheme for antenna stabilization for line-of-sight (LOS) communications to a commercial satellite operating at Ku-band. Harsh terminal platform dynamic conditions while communicating with the satellite necessitate the use of tracking antennas and stabilized platform pedestals. The hybrid tracking system design includes open loop tracking with periodic closed loop updates to correct for drifting of the inertial system. It combines the use of fiber optic gyroscopic (FOG) sensors with RF-based conical gimbal/step scan feedback. While the gyros compensate for the fast vehicle motion, the lower bandwidth RF tracking loop corrects for the low rate/DC drift errors. The novelty in our approach consists of combining these two tracking loops to minimize the tracking scan-loss. The low-cost aspect of our platform stabilization design is credited to the use of FOG sensors. The hybrid design relies heavily on the use of high quality FOGs to track in a "selective-open loop (RF-wise) pointing mode".
{"title":"Commercial Ku-band SATCOM on-the-move using a hybrid tracking scheme","authors":"T.E. Ioakimidis, R. Wexler","doi":"10.1109/MILCOM.2001.985944","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985944","url":null,"abstract":"The US Army has a requirement for long range communications to lower echelon tactical operations centers (TOCs) on-the-move (OTM). Current terrestrial radios are severely range-limited. The MITRE mission oriented investigation and experimentation (MOIE) project calls for the design and prototyping of an affordable satellite communications (SATCOM) terminal. The platform stabilization subsystem is a key component of the MITRE program. We propose a new hybrid-tracking scheme for antenna stabilization for line-of-sight (LOS) communications to a commercial satellite operating at Ku-band. Harsh terminal platform dynamic conditions while communicating with the satellite necessitate the use of tracking antennas and stabilized platform pedestals. The hybrid tracking system design includes open loop tracking with periodic closed loop updates to correct for drifting of the inertial system. It combines the use of fiber optic gyroscopic (FOG) sensors with RF-based conical gimbal/step scan feedback. While the gyros compensate for the fast vehicle motion, the lower bandwidth RF tracking loop corrects for the low rate/DC drift errors. The novelty in our approach consists of combining these two tracking loops to minimize the tracking scan-loss. The low-cost aspect of our platform stabilization design is credited to the use of FOG sensors. The hybrid design relies heavily on the use of high quality FOGs to track in a \"selective-open loop (RF-wise) pointing mode\".","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":"127087395","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.2001.986004
J. Damnjanovic, B. Vojcic
Antenna diversity and turbo multiuser detection are two promising techniques for combating channel impairments and multiple-access interference. In this paper, we propose a novel scheme for a turbo coded system with both transmit and receive antenna diversity that employs iterative multiuser detection and decoding. Multiuser detection is embedded into single-user turbo decoding. After each turbo decoding iteration, the extrinsic information of the interfering users is passed to the multiuser detector, and after each multiuser iteration, updated a posteriori probabilities are passed to the single-user turbo decoders as the soft input metrics. The proposed scheme achieves excellent performance, about 1.8 [dB] away from multiuser capacity for multiple antennas. It is shown that depending on the channel characteristics, for a fixed spectral efficiency, that is for a fixed number of virtual users K/sub v/=KT/sub x/, there exists a trade-off between the number of active users K and the number of transmit antennas T/sub x/.
{"title":"Transmit-receive antenna diversity and turbo multiuser detection","authors":"J. Damnjanovic, B. Vojcic","doi":"10.1109/MILCOM.2001.986004","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986004","url":null,"abstract":"Antenna diversity and turbo multiuser detection are two promising techniques for combating channel impairments and multiple-access interference. In this paper, we propose a novel scheme for a turbo coded system with both transmit and receive antenna diversity that employs iterative multiuser detection and decoding. Multiuser detection is embedded into single-user turbo decoding. After each turbo decoding iteration, the extrinsic information of the interfering users is passed to the multiuser detector, and after each multiuser iteration, updated a posteriori probabilities are passed to the single-user turbo decoders as the soft input metrics. The proposed scheme achieves excellent performance, about 1.8 [dB] away from multiuser capacity for multiple antennas. It is shown that depending on the channel characteristics, for a fixed spectral efficiency, that is for a fixed number of virtual users K/sub v/=KT/sub x/, there exists a trade-off between the number of active users K and the number of transmit antennas T/sub x/.","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":"127380265","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.2001.986022
Fengfan Yang, R. Tafazolli, B. Evans, M. Ye
We present a new adaptive approach for iterative turbo decoding using a pseudorandom training sequence with the distribution patterns known by both the transmitter and receiver, which can be adaptively sent to the receiver whenever the channel status changes. The branch detector computes the conditional distributions of extrinsic values produced by both arms at each iterative decoding with the aid of the training sequence. These updated probabilities are obtained instead of the traditional Gaussian law for further iterative decoding of information bits over additive white Gaussian noise and various fading channels. Such an adaptive decoding has considerable gains, investigated by the numerical simulation, over the traditional approach under the same conditions.
{"title":"New adaptive iterative turbo decoding with a training sequence over AWGN and fading channels","authors":"Fengfan Yang, R. Tafazolli, B. Evans, M. Ye","doi":"10.1109/MILCOM.2001.986022","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986022","url":null,"abstract":"We present a new adaptive approach for iterative turbo decoding using a pseudorandom training sequence with the distribution patterns known by both the transmitter and receiver, which can be adaptively sent to the receiver whenever the channel status changes. The branch detector computes the conditional distributions of extrinsic values produced by both arms at each iterative decoding with the aid of the training sequence. These updated probabilities are obtained instead of the traditional Gaussian law for further iterative decoding of information bits over additive white Gaussian noise and various fading channels. Such an adaptive decoding has considerable gains, investigated by the numerical simulation, over the traditional approach under the same conditions.","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":"125066728","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.2001.986025
H. Gharavi
This paper presents a method of transmitting video over the cdma2000 mobile system. In this method, the video bit-stream after splitting, is transmitted via the supplemental channels of the cdma2000 reverse link. The method takes advantage of the direct spread multiplexing structure of the supplemental channels to transmit divided video at differing priority classes. This is accomplished by adopting the relative gain adjustment strategy where the most error sensitive video information is transmitted via a channel with higher power The most challenging aspect of this investigation has been to maintain full compatibility with the cdma2000 standard. In particular for the reverse link where the power allocation is tightly controlled, this strategy has been successfully deployed by taking advantage of the flexibility of its link budget. Finally, we demonstrate that this strategy can result in a significantly higher quality of the reconstructed video data when transmitted over time-varying multipath fading of IMT-2000 channels.
{"title":"Video transmission for third generation mobile communication systems","authors":"H. Gharavi","doi":"10.1109/MILCOM.2001.986025","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986025","url":null,"abstract":"This paper presents a method of transmitting video over the cdma2000 mobile system. In this method, the video bit-stream after splitting, is transmitted via the supplemental channels of the cdma2000 reverse link. The method takes advantage of the direct spread multiplexing structure of the supplemental channels to transmit divided video at differing priority classes. This is accomplished by adopting the relative gain adjustment strategy where the most error sensitive video information is transmitted via a channel with higher power The most challenging aspect of this investigation has been to maintain full compatibility with the cdma2000 standard. In particular for the reverse link where the power allocation is tightly controlled, this strategy has been successfully deployed by taking advantage of the flexibility of its link budget. Finally, we demonstrate that this strategy can result in a significantly higher quality of the reconstructed video data when transmitted over time-varying multipath fading of IMT-2000 channels.","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":"125114065","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.2001.986078
J. Namgoong, J. Lehnert
Multicarrier direct-sequence spread-spectrum multiple-access (MC/DS/SSMA) systems in frequency-selective fading channels are investigated. A consistent channel model is used for each system. First, the tapped delay line (TDL) channel model with uniformly spaced, uncorrelated taps is investigated to model a complex Gaussian, wide-sense stationary, uncorrelated scattering channel. An approximate average bit error rate expression is obtained for the receiver with RAKE fingers on each subcarrier branch, whose outputs are combined according to the maximum signal-to-noise ratio criterion. Various system configurations are examined for the same TDL channel model, data rate, total system bandwidth and excess bandwidth of the chip waveform.
{"title":"Performance analysis for multicarrier DS/SSMA in frequency-selective fading channels","authors":"J. Namgoong, J. Lehnert","doi":"10.1109/MILCOM.2001.986078","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986078","url":null,"abstract":"Multicarrier direct-sequence spread-spectrum multiple-access (MC/DS/SSMA) systems in frequency-selective fading channels are investigated. A consistent channel model is used for each system. First, the tapped delay line (TDL) channel model with uniformly spaced, uncorrelated taps is investigated to model a complex Gaussian, wide-sense stationary, uncorrelated scattering channel. An approximate average bit error rate expression is obtained for the receiver with RAKE fingers on each subcarrier branch, whose outputs are combined according to the maximum signal-to-noise ratio criterion. Various system configurations are examined for the same TDL channel model, data rate, total system bandwidth and excess bandwidth of the chip waveform.","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":"125389713","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.2001.985813
G. Bostrom, R. Axford
The USA Navy (USN) Challenge Athena (CA) program, which provides two-way shipboard satellite communications (SATCOM) at data rates up to 1.544 Mbit/s (T1), utilizes the C-band frequencies 5925-6425 MHz Earth-to-space and 3700-4200 MHz space-to-Earth. The International Telecommunication Union (ITU) has allocated C-band for the fixed satellite service (FSS) and the point-to-point, line-of-sight microwave links of the fixed service (FS) on a co-primary basis throughout the world. CA is best described as a broadband maritime mobile satellite service (MMSS), a subset of the mobile services (MS). However, there is no ITU MS, let alone MMSS, allocation in C-band. Therefore, from a regulatory perspective, CA's operation must be done on a not-to-interfere basis, without protection from electromagnetic interference (EMI) caused by incumbent users of the band (i.e., the FS and FSS). But the USN is not alone with requirements for broadband services that must be provided throughout the oceans. Earth stations on vessels ("ESV" as they are referred to in the ITU) are also widely used by the cruise ship and offshore oil industries. Therefore, delegates representing several broadband maritime SATCOM service providers are cooperating with FS delegates in ITU Radiocommunication Bureau (ITU-R) Working Party 4-9S to study the potential for interference from ESV and to develop ITU-R Recommendations for ESV use of FS/FSS shared frequency bands. This paper discusses WP 4-9S ESV-on-FS interference avoidance studies, which are currently being conducted in preparation for World Radiocommunication Conference 2003 (WRC-2003). The methods described herein could be adapted to other situations where mobile satellite service (MSS) transmissions might interfere with FS and FSS systems.
{"title":"A review of ongoing ITU-R studies to allow shipboard SATCOM systems to use frequency bands shared by the fixed satellite and fixed services","authors":"G. Bostrom, R. Axford","doi":"10.1109/MILCOM.2001.985813","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985813","url":null,"abstract":"The USA Navy (USN) Challenge Athena (CA) program, which provides two-way shipboard satellite communications (SATCOM) at data rates up to 1.544 Mbit/s (T1), utilizes the C-band frequencies 5925-6425 MHz Earth-to-space and 3700-4200 MHz space-to-Earth. The International Telecommunication Union (ITU) has allocated C-band for the fixed satellite service (FSS) and the point-to-point, line-of-sight microwave links of the fixed service (FS) on a co-primary basis throughout the world. CA is best described as a broadband maritime mobile satellite service (MMSS), a subset of the mobile services (MS). However, there is no ITU MS, let alone MMSS, allocation in C-band. Therefore, from a regulatory perspective, CA's operation must be done on a not-to-interfere basis, without protection from electromagnetic interference (EMI) caused by incumbent users of the band (i.e., the FS and FSS). But the USN is not alone with requirements for broadband services that must be provided throughout the oceans. Earth stations on vessels (\"ESV\" as they are referred to in the ITU) are also widely used by the cruise ship and offshore oil industries. Therefore, delegates representing several broadband maritime SATCOM service providers are cooperating with FS delegates in ITU Radiocommunication Bureau (ITU-R) Working Party 4-9S to study the potential for interference from ESV and to develop ITU-R Recommendations for ESV use of FS/FSS shared frequency bands. This paper discusses WP 4-9S ESV-on-FS interference avoidance studies, which are currently being conducted in preparation for World Radiocommunication Conference 2003 (WRC-2003). The methods described herein could be adapted to other situations where mobile satellite service (MSS) transmissions might interfere with FS and FSS systems.","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":"126752479","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.2001.985942
F. S. Sutton, J.H. Kim, D. Diener, M. P. Pounds, R. Welling
Boeing has recently demonstrated a mobile satellite ground terminal that will support satellite communications on-the-move as well as on-the-halt. The terminal (known as "mobile wideband testbed") is a mobile satellite communications ground terminal implemented on a high mobility multipurpose wheeled vehicle. The testbed is capable of simulating and testing a wide range of networks (e.g., ATM, IP) and protocols (e.g., TCP, mobile IP) over satellite links and wireless LANs. This paper describes testbed implementation details, operation and advanced features.
{"title":"Wideband on-the-move satellite communications ground terminal","authors":"F. S. Sutton, J.H. Kim, D. Diener, M. P. Pounds, R. Welling","doi":"10.1109/MILCOM.2001.985942","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.985942","url":null,"abstract":"Boeing has recently demonstrated a mobile satellite ground terminal that will support satellite communications on-the-move as well as on-the-halt. The terminal (known as \"mobile wideband testbed\") is a mobile satellite communications ground terminal implemented on a high mobility multipurpose wheeled vehicle. The testbed is capable of simulating and testing a wide range of networks (e.g., ATM, IP) and protocols (e.g., TCP, mobile IP) over satellite links and wireless LANs. This paper describes testbed implementation details, operation and advanced features.","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":"115085010","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.2001.986014
J. Damnjanovic, B. Vojcic
In this paper we propose joint multiuser detection and packet combining in conjunction with an error control retransmission protocol to improve throughput in multiuser communications. Multiuser detection utilizes advanced signal processing techniques to demodulate the user's data by exploiting the structure of multiuser interference. Packet combining is an enhancement of the standard automatic repeat request protocol, whereby the erroneous packets are not discarded but preserved and combined with retransmitted ones to improve new decisions. Three schemes - optimum detection of combined packets and two suboptimum multiuser detection schemes - are suggested. Using the Markov chain theory we present a method for throughput calculation. It is shown that the obtained theoretical values closely agree with the simulation results. The proposed packet combining with multiuser detection is an adaptive scheme with considerably improved robustness and capacity.
{"title":"Optimum and suboptimum multiuser detection for diversity combining in DS/CDMA systems","authors":"J. Damnjanovic, B. Vojcic","doi":"10.1109/MILCOM.2001.986014","DOIUrl":"https://doi.org/10.1109/MILCOM.2001.986014","url":null,"abstract":"In this paper we propose joint multiuser detection and packet combining in conjunction with an error control retransmission protocol to improve throughput in multiuser communications. Multiuser detection utilizes advanced signal processing techniques to demodulate the user's data by exploiting the structure of multiuser interference. Packet combining is an enhancement of the standard automatic repeat request protocol, whereby the erroneous packets are not discarded but preserved and combined with retransmitted ones to improve new decisions. Three schemes - optimum detection of combined packets and two suboptimum multiuser detection schemes - are suggested. Using the Markov chain theory we present a method for throughput calculation. It is shown that the obtained theoretical values closely agree with the simulation results. The proposed packet combining with multiuser detection is an adaptive scheme with considerably improved robustness and capacity.","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":"116116102","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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