Pub Date : 2000-10-29DOI: 10.1109/ACSSC.2000.911256
J. Manton, Y. Hua
Many channel identification algorithms do not take into account the fact that the source symbols belong to a finite alphabet. This paper proposes an algorithm which exploits this finite alphabet property to refine the estimates of the source symbols and channel parameters obtained by any identification algorithm. The key idea is to reformulate the problem as minimising a quadratic cost function on a set of discrete points. Since it is known that this problem is NP-hard, a randomised algorithm is proposed, which guesses the direction in which to search for the minimum.
{"title":"A randomised algorithm for improving source and channel estimates by exploiting the finite alphabet property","authors":"J. Manton, Y. Hua","doi":"10.1109/ACSSC.2000.911256","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911256","url":null,"abstract":"Many channel identification algorithms do not take into account the fact that the source symbols belong to a finite alphabet. This paper proposes an algorithm which exploits this finite alphabet property to refine the estimates of the source symbols and channel parameters obtained by any identification algorithm. The key idea is to reformulate the problem as minimising a quadratic cost function on a set of discrete points. Since it is known that this problem is NP-hard, a randomised algorithm is proposed, which guesses the direction in which to search for the minimum.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"15 1","pages":"1582-1585 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85412416","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911015
Kun Wang, H. Ge
A new Kalman filter based space-time (S-T) receiver is proposed in this paper. By modeling an asynchronous CDMA system as a first-order state-space model, we can recursively obtain the finite-length linear minimum mean square error (LMMSE) receiver, which provides the best multiple access interference (MAI) cancellation among all the linear filters. Further interference suppression is provided by the spatial beam-former. The proposed receiver overcomes the near-far problem existing in the conventional joint S-T RAKE receiver. Simulation results demonstrate that the proposed Kalman filter based S-T receiver significantly outperforms the conventional joint S-T RAKE receiver.
{"title":"A space-time receiver for asynchronous DS-CDMA systems based on Kalman filter","authors":"Kun Wang, H. Ge","doi":"10.1109/ACSSC.2000.911015","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911015","url":null,"abstract":"A new Kalman filter based space-time (S-T) receiver is proposed in this paper. By modeling an asynchronous CDMA system as a first-order state-space model, we can recursively obtain the finite-length linear minimum mean square error (LMMSE) receiver, which provides the best multiple access interference (MAI) cancellation among all the linear filters. Further interference suppression is provided by the spatial beam-former. The proposed receiver overcomes the near-far problem existing in the conventional joint S-T RAKE receiver. Simulation results demonstrate that the proposed Kalman filter based S-T receiver significantly outperforms the conventional joint S-T RAKE receiver.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"63 1","pages":"547-551 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79499776","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911219
Z. Liu, G. Abousleman, Lina Karam
This paper presents a low bit rate error-resilient channel-optimized coder for the transmission of video over the binary symmetric channel. The proposed coder uses a channel-optimized trellis-coded quantization (COTCQ) stage that is designed to optimize the video coding based on the channel characteristics. The resilience to channel errors is obtained by optimizing the coder performance only at the level of the source encoder, with no explicit use of channel coding for error protection. Additionally, due to the novel adaptive nature of the coder, the need for entropy coding and motion compensation is eliminated. Simulation results show that our coder provides outstanding quantitative and subjective coding performance for a wide variety of bit error rates, without the use of error concealment techniques.
{"title":"Error-robust video coding with channel-optimized trellis-coded quantization","authors":"Z. Liu, G. Abousleman, Lina Karam","doi":"10.1109/ACSSC.2000.911219","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911219","url":null,"abstract":"This paper presents a low bit rate error-resilient channel-optimized coder for the transmission of video over the binary symmetric channel. The proposed coder uses a channel-optimized trellis-coded quantization (COTCQ) stage that is designed to optimize the video coding based on the channel characteristics. The resilience to channel errors is obtained by optimizing the coder performance only at the level of the source encoder, with no explicit use of channel coding for error protection. Additionally, due to the novel adaptive nature of the coder, the need for entropy coding and motion compensation is eliminated. Simulation results show that our coder provides outstanding quantitative and subjective coding performance for a wide variety of bit error rates, without the use of error concealment techniques.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"148 1","pages":"1389-1393 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79838090","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911013
Ashwin Ganesan, A. Sayeed
We develop a virtual MIMO (multiple input multiple output) framework for characterizing single-transmitter single-receiver multipath channels. We arrive at four different MIMO channel models depending on the basis functions used to characterize the signal space dimensions. The MIMO representation reveals the relation between the factors that affect system performance and facilitates transceiver design. Specific transceiver structures are represented by special cases of the MIMO models. The framework makes it possible to determine closed form expressions for ergodic and outage capacity for a variety of transceivers. A simple transceiver is proposed that transforms the multipath channel into a virtual multiple antenna array system to which space-time codes can be directly applied.
{"title":"A virtual MIMO framework for multipath fading channels","authors":"Ashwin Ganesan, A. Sayeed","doi":"10.1109/ACSSC.2000.911013","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911013","url":null,"abstract":"We develop a virtual MIMO (multiple input multiple output) framework for characterizing single-transmitter single-receiver multipath channels. We arrive at four different MIMO channel models depending on the basis functions used to characterize the signal space dimensions. The MIMO representation reveals the relation between the factors that affect system performance and facilitates transceiver design. Specific transceiver structures are represented by special cases of the MIMO models. The framework makes it possible to determine closed form expressions for ergodic and outage capacity for a variety of transceivers. A simple transceiver is proposed that transforms the multipath channel into a virtual multiple antenna array system to which space-time codes can be directly applied.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"19 1","pages":"537-541 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84395895","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911304
N. Thorwirth, P. Horvatic, R. Weis, Jian Zhao
The impetus for the work presented in this paper arose from the need to enable Internet-based secure audio delivery and protection of digitized music against illegal distribution. The approach described, provides protection for the widely accepted MPEG-1 Layer-3 audio encoding format, although it can easily be applied to any other perceptual audio coding (PAC) standard. During the process of MP3 encoding, selective, content-based security features are added to the stream in order to de-couple and protect individual layers of audio quality while introducing minimal processing overhead and maintaining the audio format. In addition to quality-layered protection, we propose simultaneous use of our audio watermarking technology for a complete solution in network-based secure audio delivery and copyright protection.
{"title":"Security methods for MP3 music delivery","authors":"N. Thorwirth, P. Horvatic, R. Weis, Jian Zhao","doi":"10.1109/ACSSC.2000.911304","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911304","url":null,"abstract":"The impetus for the work presented in this paper arose from the need to enable Internet-based secure audio delivery and protection of digitized music against illegal distribution. The approach described, provides protection for the widely accepted MPEG-1 Layer-3 audio encoding format, although it can easily be applied to any other perceptual audio coding (PAC) standard. During the process of MP3 encoding, selective, content-based security features are added to the stream in order to de-couple and protect individual layers of audio quality while introducing minimal processing overhead and maintaining the audio format. In addition to quality-layered protection, we propose simultaneous use of our audio watermarking technology for a complete solution in network-based secure audio delivery and copyright protection.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"48 1","pages":"1831-1835 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84655615","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910678
Shahrnaz Azizit, Cochrant, John, McDonald
This paper proposes a region-selective image compression method that is motivated by the nonuniform sampling structure of the human eye. The approach is based on the nonuniform sampling theorem of Clark et al. (1985) for time-warped bandlimited functions. The theoretical underpinnings of the method are explained and examples are presented to illustrate its implementation and performance.
{"title":"A sampling approach to region-selective image compression","authors":"Shahrnaz Azizit, Cochrant, John, McDonald","doi":"10.1109/ACSSC.2000.910678","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910678","url":null,"abstract":"This paper proposes a region-selective image compression method that is motivated by the nonuniform sampling structure of the human eye. The approach is based on the nonuniform sampling theorem of Clark et al. (1985) for time-warped bandlimited functions. The theoretical underpinnings of the method are explained and examples are presented to illustrate its implementation and performance.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"183 1","pages":"1063-1067 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80383878","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911020
E. Lindskog, D. Flore
In this paper we evaluate the performance of what we call here, time-reversal space-time block coding (Lindskog and Paulraj 2000) combined with transmit delay diversity (Wittneben 1991). For comparison we also report on the performance of the two schemes separate, earlier studied in Flore and Lindskog (2000). When combining the two methods we transmit from four antennas and when studying the methods separately we transmit from two antennas. The methods are evaluated in a GSM-like system using test channels from the GSM standard. The time-reversal space-time coding scheme outperforms the transmit delay diversity scheme in two manners. First it achieves a higher SNR gain and second it does not increase memory in the channel and thus does not increase the complexity of the equalizer in the receiver. The combination of the time-reversal space-time coding scheme with the transmit diversity scheme has improved performance as it achieves a higher diversity order. At a BER of 1% the transmit delay diversity and the time-reversal space-lime block coding scheme use separately transmitting from two antennas achieves a gain of 2.5 dB and 3 dB respectively, for an urban scenario and 4.0 and 5.0 dB for a rural scenario, compared to single antenna transmission. When the two methods are combined transmitting from four antennas, a gain of 4.0 dB and 6.0 dB is achieved for the urban and the rural scenarios, respectively.
在本文中，我们评估了我们称之为时间反转空时分组编码(Lindskog and Paulraj 2000)结合传输延迟分集(Wittneben 1991)的性能。为了进行比较，我们还分别报告了Flore和Lindskog(2000)早期研究的两种方案的性能。当两种方法结合时，我们从四个天线发射;当单独研究两种方法时，我们从两个天线发射。使用来自GSM标准的测试通道，在类似GSM的系统中对这些方法进行了评估。时间反转空时编码方案在两个方面优于发射延迟分集方案。首先，它实现了更高的信噪比增益，其次，它不会增加信道中的内存，因此不会增加接收器中均衡器的复杂性。时间反转空时编码方案与发射分集方案相结合，实现了更高的分集阶，提高了性能。与单天线传输相比，在BER为1%时，分别从两个天线发射的发射延迟分集和时反转空块编码方案分别获得2.5 dB和3db的增益，用于城市场景，4.0和5.0 dB用于农村场景。当两种方法结合使用时，城市和农村场景的增益分别为4.0 dB和6.0 dB。
{"title":"Time-reversal space-time block coding and transmit delay diversity-separate and combined","authors":"E. Lindskog, D. Flore","doi":"10.1109/ACSSC.2000.911020","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911020","url":null,"abstract":"In this paper we evaluate the performance of what we call here, time-reversal space-time block coding (Lindskog and Paulraj 2000) combined with transmit delay diversity (Wittneben 1991). For comparison we also report on the performance of the two schemes separate, earlier studied in Flore and Lindskog (2000). When combining the two methods we transmit from four antennas and when studying the methods separately we transmit from two antennas. The methods are evaluated in a GSM-like system using test channels from the GSM standard. The time-reversal space-time coding scheme outperforms the transmit delay diversity scheme in two manners. First it achieves a higher SNR gain and second it does not increase memory in the channel and thus does not increase the complexity of the equalizer in the receiver. The combination of the time-reversal space-time coding scheme with the transmit diversity scheme has improved performance as it achieves a higher diversity order. At a BER of 1% the transmit delay diversity and the time-reversal space-lime block coding scheme use separately transmitting from two antennas achieves a gain of 2.5 dB and 3 dB respectively, for an urban scenario and 4.0 and 5.0 dB for a rural scenario, compared to single antenna transmission. When the two methods are combined transmitting from four antennas, a gain of 4.0 dB and 6.0 dB is achieved for the urban and the rural scenarios, respectively.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"3 1","pages":"572-577 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82397159","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910700
C. Spooner, W. A. Brown, G. K. Yeung
The ability to automatically characterize all RF sources that have significant energy at a particular point in space has important applications in scientific, military, and industrial settings. Examples include automatic characterization of interference in radio astronomy, automatic signal detection and classification for military surveillance, and interference characterization for communication-system test and evaluation. Such analyses are particularly difficult when the unknown RF signals overlap in both time and frequency or when the number of possible signal types is large. We present a method of automatically detecting, characterizing, and classifying each of a number of RF sources that can spectrally and temporally overlap and that can be weak relative to the receiver noise. The method exploits the structure of higher-order statistics of man-made RF signals.
{"title":"Automatic radio-frequency environment analysis","authors":"C. Spooner, W. A. Brown, G. K. Yeung","doi":"10.1109/ACSSC.2000.910700","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910700","url":null,"abstract":"The ability to automatically characterize all RF sources that have significant energy at a particular point in space has important applications in scientific, military, and industrial settings. Examples include automatic characterization of interference in radio astronomy, automatic signal detection and classification for military surveillance, and interference characterization for communication-system test and evaluation. Such analyses are particularly difficult when the unknown RF signals overlap in both time and frequency or when the number of possible signal types is large. We present a method of automatically detecting, characterizing, and classifying each of a number of RF sources that can spectrally and temporally overlap and that can be weak relative to the receiver noise. The method exploits the structure of higher-order statistics of man-made RF signals.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"1 1","pages":"1181-1186 vol.2"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82926345","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.911023
Sangwoo Cho, Haekyung Jwa, J. Chun, J. H. Lee, Yoon Seok Jung
We propose a new method for tracking a mobile by monitoring the signal powers of the mobile transmitter measured at several base stations. The signal power measurement at a base station, which is sometimes called a power map, is a non-linear (empirical) function of the position of a mobile. We propose to use the Bayesian bootstrap filtering approach to cope with the nonlinearity, assuming that the mobile is vehicle-mounted so that the movement of the mobile is confined in a road.
{"title":"Mobile position location with the constrained bootstrap filter in a cellular communication system","authors":"Sangwoo Cho, Haekyung Jwa, J. Chun, J. H. Lee, Yoon Seok Jung","doi":"10.1109/ACSSC.2000.911023","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.911023","url":null,"abstract":"We propose a new method for tracking a mobile by monitoring the signal powers of the mobile transmitter measured at several base stations. The signal power measurement at a base station, which is sometimes called a power map, is a non-linear (empirical) function of the position of a mobile. We propose to use the Bayesian bootstrap filtering approach to cope with the nonlinearity, assuming that the mobile is vehicle-mounted so that the movement of the mobile is confined in a road.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"47 1","pages":"590-594 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83344672","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 : 2000-10-29DOI: 10.1109/ACSSC.2000.910925
B. Raghothaman, G. Mandyam, R. T. Derryberry
Closed loop multi-antenna diversity transmission methods are being considered for 3/sup rd/ generation wireless standards. In these techniques, information about the downlink channel is fed back to the base station and utilized to provide diversity as well as antenna gain at low mobile velocities under flat fading conditions. The performance, however, drops at higher velocities, mainly due to the delay involved in the feedback of antenna weights. We analyze this behavior, with the aim of quantifying the degradation in average received signal power as a function of velocity. The two cases of complex weight feedback and pure phase feedback are considered. The analysis will help to determine a useful velocity range in which closed loop diversity is feasible.
{"title":"Performance of closed loop transmit diversity with feedback delay","authors":"B. Raghothaman, G. Mandyam, R. T. Derryberry","doi":"10.1109/ACSSC.2000.910925","DOIUrl":"https://doi.org/10.1109/ACSSC.2000.910925","url":null,"abstract":"Closed loop multi-antenna diversity transmission methods are being considered for 3/sup rd/ generation wireless standards. In these techniques, information about the downlink channel is fed back to the base station and utilized to provide diversity as well as antenna gain at low mobile velocities under flat fading conditions. The performance, however, drops at higher velocities, mainly due to the delay involved in the feedback of antenna weights. We analyze this behavior, with the aim of quantifying the degradation in average received signal power as a function of velocity. The two cases of complex weight feedback and pure phase feedback are considered. The analysis will help to determine a useful velocity range in which closed loop diversity is feasible.","PeriodicalId":10581,"journal":{"name":"Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154)","volume":"72 1","pages":"102-105 vol.1"},"PeriodicalIF":0.0,"publicationDate":"2000-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78659297","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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