{"title":"On narrowband interference suppression using DFB filter in DSSS systems under impulsive channel conditions","authors":"Z.S. Dobrosavljevi, M. Dukic","doi":"10.1109/ISSSTA.1994.379529","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379529","url":null,"abstract":"In this paper the extension analysis of the recently proposed direct sequence spread spectrum (DSSS) receiver using decision feedback filter (DFB) under narrowband interference (NBI) and impulsive channel conditions is presented. The results, obtained by theoretical analysis and computer simulation in term of the output signal to interference ratio (SIR), show that the impulsive noise does not deteriorate the excellent performance of the DFB receiver in the NBI suppression. The impulsive noise influence on the receiver performance can be adequately expressed through the increase of the total noise power.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115343457","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}
{"title":"An evaluation of the effects of quantization technique on the performance of digital matched filters in a direct sequence spread spectrum receiver","authors":"W.K. Miller, J. Lansford","doi":"10.1109/ISSSTA.1994.379566","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379566","url":null,"abstract":"Digital matched filter (DMF) receivers offer implementation advantages over analog matched filter (AMF) receivers for direct sequence spread spectrum communications systems at the cost of some loss of performance. The level of performance lost is related in large part to the technique used for analog-to-digital conversion (ADC). The performance of various analog-to-digital conversion techniques are evaluated by means of the receiver operating characteristics (ROC) as described by Van Trees (1968).<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"162 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115428044","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}
{"title":"Influence of data modulation and Doppler effects on the performance of a delay locked loop","authors":"U. Bernhard","doi":"10.1109/ISSSTA.1994.379515","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379515","url":null,"abstract":"The influence of Doppler effects on the tracking performance of a noncoherent second-order delay-locked loop (DLL) operating on a data modulated signal is investigated. For the performance analysis the author considers the tracking accuracy (steady state error and jitter) of the linear DLL and the reliability of the nonlinear loop. The nonlinear analysis concerning the loop reliability makes use of an asymptotic expansion for the mean exit time (mean time to lose lock, MTLL) which has been derived by applying the singular perturbation method. In particular, the author gives optimal loop parameters and the optimal bandwidth of the bandpass filter in the loop arms to achieve a maximum MTLL. Due to Doppler effects the optimal loop parameters are rather different using either linear or nonlinear analyses.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123771701","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}
{"title":"A hybrid breadth/depth first technique to improve convolutionally encoded /spl pi/4-shifted DQPSK over asynchronous CDMA fading channels","authors":"M. Martone, V. E. Maragliano, A. Spazio","doi":"10.1109/ISSSTA.1994.379584","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379584","url":null,"abstract":"A direct sequence spread spectrum multiple access communication system based on differential /spl pi/4-shifted QPSK modulation and convolutional coding is analyzed. The channel model is frequency selective fading typical of mobile digital radio systems. An efficient decoding scheme is proposed to relieve performance losses at the receiver due to user interference. Sequential decoding is a valid alternative to Viterbi decoding, and particularly the backtracking algorithm when long constraints convolutional codes are imposed by system performance. Purely breadth first sequential decoding algorithms such as the M-algorithm present inherent parallelism (adapt to a parallel HW realization) but are, as pointed out by Anderson [1992], less efficient in terms of average number of paths searched with respect to the backtracking algorithm, while representing a search performed by the Viterbi algorithm. The authors propose a technique which is a modified version of a Fano-like algorithm in which the forward operations are performed by means of a breadth first algorithm: this modification presents many advantages. First of all, backtracking events are limited. In this way the decoder proceeds faster and with a lower delay. Second: the searches are made in parallel, allowing a smaller buffering and hence a simpler VLSI realization with respect to the traditional Fano decoder. An analysis is performed of the uncoded detection scheme and the results of the simulations of the encoded scheme are compared. Large coding gains seem possible when employing an adapt interleaving and an efficient power control system.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125136612","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}
{"title":"Information theory aspects of spread-spectrum communications","authors":"J. Massey","doi":"10.1109/ISSSTA.1994.379621","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379621","url":null,"abstract":"A novel definition of a spread-spectrum system as a communications system in which the Fourier bandwidth is much greater than the Shannon bandwith (the number of dimensions of signal space used per second) is proposed. Six different communication systems are analyzed in terms of this definition. It is shown that there is a fundamental difference between the bandwidth expansion due to coding and due to \"spectrum spreading\". It is further shown that spectrum spreading plays no role in increasing the capacity of the system, but can perform other useful roles such as providing low probability of interception of the signal, good electromagnetic compatibility, and a multiple-access capability.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121749155","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}
{"title":"Convolutional coding for a phase modulated FCMA system","authors":"R. Boreli, K. Yates","doi":"10.1109/ISSSTA.1994.379579","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379579","url":null,"abstract":"The paper investigates the benefits of non-binary convolutional coding applied to a phase modulated frequency COMB94 multiple access (PFCMA) system. PFCMA is a novel multiple access technique proposed for very small aperture terminal (VSAT) satellite communications networks which encompasses multi-tone transmission with spread spectrum techniques. Previous work (Boreli and Yates, 1993) analysed the PFCMA error performance and indicated a need for error correction coding in order to improve the power efficiency. Non-binary convolutional codes with matching symbol size were chosen to fully exploit the benefits of soft decision decoding. The present authors present a study of coded system performance and illustrate it with a number of examples.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129513025","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}
{"title":"Even- and odd-correlation functions of chaotic Chebyshev bit sequences for CDMA","authors":"T. Kohda, A. Tsuneda","doi":"10.1109/ISSSTA.1994.379557","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379557","url":null,"abstract":"Chaotic binary sequences generated by Chebyshev maps are discussed. Their even- and odd-correlation functions are explicitly evaluated by means of the ensemble-average technique. Such sequences are shown to be good candidates of spreading codes (pseudonoise sequences) for CDMA.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132967085","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}
{"title":"Performance analysis of an overlay CDMA system with multiple BPSK interferers","authors":"M. Widjaja, H. S. Misser, R. Prasad","doi":"10.1109/ISSSTA.1994.379533","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379533","url":null,"abstract":"This paper describes the performance analysis of a direct sequence code division multiple access (DS-CDMA) system sharing common spectrum with narrowband interferences. The performance is investigated in terms of the bit error rate (BER) of a DS-CDMA system being multiple BPSK interferers, and evaluated as a function of BPSK and CDMA users. To enhance the performance of the receiver, a suppression filter is employed to reduce interference.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134389059","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}
{"title":"Performance of distributed power spread spectrum cellular system","authors":"A. Otsuka, S. Tachikawa, G. Marubayashi","doi":"10.1109/ISSSTA.1994.379598","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379598","url":null,"abstract":"This paper proposes a novel DPSK-DS/spread spectrum cellular system in the Rayleigh fading environment, especially suitable for small cell applications. When the radius of the cell becomes small (e.g. micro-cell), the RAKE algorithm cannot be applied in conventional DS/SS systems, however in the proposed system, a considerable diversity gain by using RAKE can be obtained. In the down-link of the proposed system, signals are transmitted from both the base stations of its own cell and the surrounding cells. To make the RAKE system effective, different time delays larger than the chip duration are allocated to the signals from the surrounding cell stations. A similar process is applied vice versa for the up-link. The results of calculations and the improvement in the bit error rate are shown.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125170433","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}
{"title":"Code synchronization: a review of principles and techniques","authors":"Andreas Polydoros, S. Glisic","doi":"10.1109/ISSSTA.1994.379608","DOIUrl":"https://doi.org/10.1109/ISSSTA.1994.379608","url":null,"abstract":"We review the main concepts underlying the derivation of appropriate receivers for code synchronization in spread spectrum systems, emphasizing a likelihood theory viewpoint. Practical structures for the separate tasks of code acquisition and tracking are discussed and categorized. A brief discussion of analysis tools and performance measures is presented, along with design considerations for threshold settings, and impact of fading. An extensive bibliography is also included.<<ETX>>","PeriodicalId":158358,"journal":{"name":"Proceedings of IEEE 3rd International Symposium on Spread Spectrum Techniques and Applications (ISSSTA'94)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127035777","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}