Pub Date : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371706
A. Caldow, G. Parker, K. Harman
A conventional demodulator for an unbalanced QPSK direct sequence spread spectrum (DSSS) signal requires carrier coherence in order to prevent cross-talk between the in-phase and quadrature (I & Q) channels of the despreading process. A noncoherent demodulator which tolerates this cross-talk has been proposed, with applicability to pilot-less burst transmission protocols. The paper focuses on the development and verification of an analytic model for the BER performance of this demodulator, and shows that, although the noise contributions of the cross-talk terms can be high, the resultant impact on BER is only slight.
{"title":"BER analysis of a noncoherent demodulation of unbalanced DQPSK DSSS","authors":"A. Caldow, G. Parker, K. Harman","doi":"10.1109/ISSSTA.2004.1371706","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371706","url":null,"abstract":"A conventional demodulator for an unbalanced QPSK direct sequence spread spectrum (DSSS) signal requires carrier coherence in order to prevent cross-talk between the in-phase and quadrature (I & Q) channels of the despreading process. A noncoherent demodulator which tolerates this cross-talk has been proposed, with applicability to pilot-less burst transmission protocols. The paper focuses on the development and verification of an analytic model for the BER performance of this demodulator, and shows that, although the noise contributions of the cross-talk terms can be high, the resultant impact on BER is only slight.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"133 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123395888","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371806
Wan Choi, J. Andrews
Direct sequence code division multiple access (DS-CDMA) receivers typically use maximal ratio combining (MRC) to favorably combine the energies of distinct multipath components from diversity branches. There have been a large number of studies on DS-CDMA and MRC receivers, respectively, but there have been a comparatively small number of papers analyzing MRC for DS-CDMA. Prior work does not accurately analyze the outage probability using the actual random characteristics of the cross correlations, instead, equality has been assumed. The contribution of this paper is to provide a general and accurate analysis of the outage probability of the diversity receiver in CDMA systems without compromising approximations. From the analytical and numerical results, it is shown that the analysis provides an accurate closed-form solution.
{"title":"Outage probability for maximal ratio combining receivers in asynchronous CDMA channels","authors":"Wan Choi, J. Andrews","doi":"10.1109/ISSSTA.2004.1371806","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371806","url":null,"abstract":"Direct sequence code division multiple access (DS-CDMA) receivers typically use maximal ratio combining (MRC) to favorably combine the energies of distinct multipath components from diversity branches. There have been a large number of studies on DS-CDMA and MRC receivers, respectively, but there have been a comparatively small number of papers analyzing MRC for DS-CDMA. Prior work does not accurately analyze the outage probability using the actual random characteristics of the cross correlations, instead, equality has been assumed. The contribution of this paper is to provide a general and accurate analysis of the outage probability of the diversity receiver in CDMA systems without compromising approximations. From the analytical and numerical results, it is shown that the analysis provides an accurate closed-form solution.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126936845","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371764
K. Zheng, Guoyan Zeng, Wenbo Wang
Multi-carrier code division multiple access (MC-CDMA) is one of the best candidates for the future broadband wireless multimedia communication systems. This paper proposes a novel channel estimation algorithm for MC-CDMA systems on the uplink. With reasonable constraint and well-designed preambles for each user, the DFT-based uplink channel estimation algorithm can achieve good estimation accuracy without sacrificing much system capacity. Computer simulation demonstrates the effectiveness of this method and our conclusion is presented.
{"title":"DFT-based uplink channel estimation in MC-CDMA systems","authors":"K. Zheng, Guoyan Zeng, Wenbo Wang","doi":"10.1109/ISSSTA.2004.1371764","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371764","url":null,"abstract":"Multi-carrier code division multiple access (MC-CDMA) is one of the best candidates for the future broadband wireless multimedia communication systems. This paper proposes a novel channel estimation algorithm for MC-CDMA systems on the uplink. With reasonable constraint and well-designed preambles for each user, the DFT-based uplink channel estimation algorithm can achieve good estimation accuracy without sacrificing much system capacity. Computer simulation demonstrates the effectiveness of this method and our conclusion is presented.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115090831","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371808
Songping Wu, Y. Bar-Ness
It has been shown that OFDM is a strong candidate for future high rate wireless communications. One drawback of OFDM is, however, its sensitivity to phase noise, which causes leakage of digital Fourier transform (DFT), leads to common phase error (CPE) as well as intercarrier interference (ICI) in the frequency domain, and therefore saturates system performance. Many methods have been developed in the literature to mitigate phase noise. Among them, a simultaneous CPE and ICI correction (SCIC) technique, which chooses to estimate and cancel CPE and ICI simultaneously, has a better performance than others. Nevertheless, this technique requires much higher computational complexity, mainly due to the matrix inversion. We propose a new SCIC-based method which, while maintaining the same performance as the original scheme, greatly reduces the computational complexity. Numerical results are provided to show the effectiveness of the proposed method.
{"title":"Computationally efficient phase noise cancellation technique in OFDM systems with phase noise","authors":"Songping Wu, Y. Bar-Ness","doi":"10.1109/ISSSTA.2004.1371808","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371808","url":null,"abstract":"It has been shown that OFDM is a strong candidate for future high rate wireless communications. One drawback of OFDM is, however, its sensitivity to phase noise, which causes leakage of digital Fourier transform (DFT), leads to common phase error (CPE) as well as intercarrier interference (ICI) in the frequency domain, and therefore saturates system performance. Many methods have been developed in the literature to mitigate phase noise. Among them, a simultaneous CPE and ICI correction (SCIC) technique, which chooses to estimate and cancel CPE and ICI simultaneously, has a better performance than others. Nevertheless, this technique requires much higher computational complexity, mainly due to the matrix inversion. We propose a new SCIC-based method which, while maintaining the same performance as the original scheme, greatly reduces the computational complexity. Numerical results are provided to show the effectiveness of the proposed method.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"292 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116454445","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371809
C. Corral, S. Emami, G. Rasor
The impact of time-frequency hopped multi-band orthogonal frequency division multiplexing (MB-OFDM) on in-band wideband receivers is considered. First, we compare direct-sequence and frequency-hopped ultra-wideband (UWB) systems in terms of power and range characteristics. We then show that in-band receivers with large bandwidths are susceptible to UWB systems, but direct sequence systems are potentially less harmful due to the large relative bandwidth. The MB-OFDM signal introduces less interference for long hop lengths, but the signal peak-to-average power rises. This makes the MB-OFDM signal appear impulsive to a victim receiver, causing destructive interference at high signal-to-noise ratios.
{"title":"In-band interference of multi-band OFDM systems","authors":"C. Corral, S. Emami, G. Rasor","doi":"10.1109/ISSSTA.2004.1371809","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371809","url":null,"abstract":"The impact of time-frequency hopped multi-band orthogonal frequency division multiplexing (MB-OFDM) on in-band wideband receivers is considered. First, we compare direct-sequence and frequency-hopped ultra-wideband (UWB) systems in terms of power and range characteristics. We then show that in-band receivers with large bandwidths are susceptible to UWB systems, but direct sequence systems are potentially less harmful due to the large relative bandwidth. The MB-OFDM signal introduces less interference for long hop lengths, but the signal peak-to-average power rises. This makes the MB-OFDM signal appear impulsive to a victim receiver, causing destructive interference at high signal-to-noise ratios.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122355626","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371727
Hyunduk Kang, Insoo Koo, Miheung Choe, Kiseon Kim
We investigate the performance of cellular CDMA systems through adopting two types of array antennas, switched beam forming (SBF) and tracking beam forming (TBF) in the base station. Also, in order to enhance the system performance, we optimize the beam shape using sidelobe-to-main-beam-energy ratio (SMER) defined by the energy ratio of the sidelobe region and main beam region. As a result, it is observed that the TBF method gives about 30 capacity improvement over the SBF method under 1 probability requirement. In addition, an optimized beam shape using SMER provides maximally 8 comparing conventional non-optimized beam shapes under 1 probability requirement when we use 5 and 7 beams per sector with the SBF method, respectively.
{"title":"Performance of cellular CDMA systems using SBF and TBF array antennas","authors":"Hyunduk Kang, Insoo Koo, Miheung Choe, Kiseon Kim","doi":"10.1109/ISSSTA.2004.1371727","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371727","url":null,"abstract":"We investigate the performance of cellular CDMA systems through adopting two types of array antennas, switched beam forming (SBF) and tracking beam forming (TBF) in the base station. Also, in order to enhance the system performance, we optimize the beam shape using sidelobe-to-main-beam-energy ratio (SMER) defined by the energy ratio of the sidelobe region and main beam region. As a result, it is observed that the TBF method gives about 30 capacity improvement over the SBF method under 1 probability requirement. In addition, an optimized beam shape using SMER provides maximally 8 comparing conventional non-optimized beam shapes under 1 probability requirement when we use 5 and 7 beams per sector with the SBF method, respectively.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122790501","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371831
T. Gyawali, H. Kwon
Most of the wideband low probability of intercept (LPI) signal detectors use energy detection and autocorrelation of the transmitted signal to decide the presence of the signal in an observed band. We propose a method for the detection of such signals using an inverse problem based approach. We compare the receiver operating characteristics (ROC) of this detector with those of conventional detectors. Simulation results indicate better performance of the proposed detector over the other LPI detectors. Furthermore, the proposed scheme is feasible and consistent because it can be implemented with modern digital signal processing of linear order computations whereas the conventional detectors are analog types and inconsistent.
{"title":"An inverse problem based approach to detection in LPI systems","authors":"T. Gyawali, H. Kwon","doi":"10.1109/ISSSTA.2004.1371831","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371831","url":null,"abstract":"Most of the wideband low probability of intercept (LPI) signal detectors use energy detection and autocorrelation of the transmitted signal to decide the presence of the signal in an observed band. We propose a method for the detection of such signals using an inverse problem based approach. We compare the receiver operating characteristics (ROC) of this detector with those of conventional detectors. Simulation results indicate better performance of the proposed detector over the other LPI detectors. Furthermore, the proposed scheme is feasible and consistent because it can be implemented with modern digital signal processing of linear order computations whereas the conventional detectors are analog types and inconsistent.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"287 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114441535","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371767
A. Ito, H. Habuchi
A simple self-synchronization system for code shift keying/spread spectrum (CSK/SS) with the differential detector is proposed. In the proposed method, a pair consisting of the Manchester-coded pseudo-noise (PN) sequence and the nonManchester-coded PN sequence is used. The cross-correlation characteristic between these sequences is used instead of the S-curve of the delay lock loop (DLL) directly. The following performance under the additive white Gaussian noise (AWGN) channel is evaluated: (1) the tracking error (jitter) performance; and (2) the bit error rate (BER) performance that takes into account the jitter. As a result, it is shown that the performance of the proposed system is better than that of the external synchronization system.
{"title":"A simple self-synchronization system for CSK/SS","authors":"A. Ito, H. Habuchi","doi":"10.1109/ISSSTA.2004.1371767","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371767","url":null,"abstract":"A simple self-synchronization system for code shift keying/spread spectrum (CSK/SS) with the differential detector is proposed. In the proposed method, a pair consisting of the Manchester-coded pseudo-noise (PN) sequence and the nonManchester-coded PN sequence is used. The cross-correlation characteristic between these sequences is used instead of the S-curve of the delay lock loop (DLL) directly. The following performance under the additive white Gaussian noise (AWGN) channel is evaluated: (1) the tracking error (jitter) performance; and (2) the bit error rate (BER) performance that takes into account the jitter. As a result, it is shown that the performance of the proposed system is better than that of the external synchronization system.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129578492","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371747
S.S. Tan, A. Nallanathan, B. Kannan
Impulse radio (IR) is an ultra-wideband (UWB) time-hopping spread spectrum technique in which sub-nanosecond pulses are modulated to convey information by shifting the position of the pulses in the time axis. We investigate channel estimation for an IR UWB system with an antenna array receiver in multipath environments with multiuser interference. The estimation method is pilot symbol assisted and it is based on the maximum likelihood criterion.
{"title":"A pilot symbol assisted channel estimation scheme for UWB IR systems with diversity reception","authors":"S.S. Tan, A. Nallanathan, B. Kannan","doi":"10.1109/ISSSTA.2004.1371747","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371747","url":null,"abstract":"Impulse radio (IR) is an ultra-wideband (UWB) time-hopping spread spectrum technique in which sub-nanosecond pulses are modulated to convey information by shifting the position of the pulses in the time axis. We investigate channel estimation for an IR UWB system with an antenna array receiver in multipath environments with multiuser interference. The estimation method is pilot symbol assisted and it is based on the maximum likelihood criterion.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"58 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128265154","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 : 2004-08-30DOI: 10.1109/ISSSTA.2004.1371846
D. Noguet, Jean-Paul Bouyoud, L. Zaghdoudi, D. Varreau, B. Jechoux, P. Le Corre, X. Lagrange, J. Nasreddine
This paper describes a hardware platform that has been designed to validate joint detection receivers for UMTS/TDD. This testbed includes transmitters, a multipath baseband channel emulation and a receiver. The receiver includes channel estimation, multiuser detection (MUD) and channel turbo decoding. It consists of a set of DSP and FPGA boards host in a PC machine that achieves real-time computation of multiuser processing at 368 kbit/s (user rate). The flexibility of the platform enables various configurations: downlink (DL), uplink (UL) and various channel conditions. Joint detection (JD) based receivers have been tested on this platform. The first one performs the JD in the temporal domain, the second one in the frequency domain. Real-time performance, hardware complexity and performance improvement compared to the RAKE receiver are discussed in this paper.
{"title":"A hardware testbed for UMTS/TDD joint detection base-band receivers","authors":"D. Noguet, Jean-Paul Bouyoud, L. Zaghdoudi, D. Varreau, B. Jechoux, P. Le Corre, X. Lagrange, J. Nasreddine","doi":"10.1109/ISSSTA.2004.1371846","DOIUrl":"https://doi.org/10.1109/ISSSTA.2004.1371846","url":null,"abstract":"This paper describes a hardware platform that has been designed to validate joint detection receivers for UMTS/TDD. This testbed includes transmitters, a multipath baseband channel emulation and a receiver. The receiver includes channel estimation, multiuser detection (MUD) and channel turbo decoding. It consists of a set of DSP and FPGA boards host in a PC machine that achieves real-time computation of multiuser processing at 368 kbit/s (user rate). The flexibility of the platform enables various configurations: downlink (DL), uplink (UL) and various channel conditions. Joint detection (JD) based receivers have been tested on this platform. The first one performs the JD in the temporal domain, the second one in the frequency domain. Real-time performance, hardware complexity and performance improvement compared to the RAKE receiver are discussed in this paper.","PeriodicalId":340769,"journal":{"name":"Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129449409","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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