Spread Spectrum Techniques and Applications Proceedings, 1996., IEEE 4th International Symposium on

25-25 Sept. 1996

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  • 1996 IEEE 4th International Symposium on Spread Spectrum Techniques and Applications Proceedings

    Publication Year: 1996, Page(s):0_3 - 0_34
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  • RA/T spreading code scheme for centralized DS/SSMA packet radio networks

    Publication Year: 1996, Page(s):1108 - 1112 vol.3
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (491 KB)

    We address an issue of channel sharing among users by using a random assignment/transmitter-oriented code scheme which permits the contention mode only in the transmission of a header. The reception of the data packet may be blocked due to limited number of correlators so that this effect is taken into account in our analysis. We also consider an acknowledgement scheme to notify whether the header... View full abstract»

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  • An orthogonal multicarrier DS-SS radio access scheme for wireless LAN

    Publication Year: 1996, Page(s):1325 - 1329 vol.3
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    This paper investigates a new radio access scheme, based on orthogonal multicarrier DS-SS, for wireless LAN. The modem scheme, the sounding and equalisation techniques and the general format of the frame for various system configurations are presented. Taking a realistic sounding technique into consideration, we report the analytical bit error rate performance and the simulation results, based on ... View full abstract»

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  • A new scheme for direct sequence spread spectrum radio LANs

    Publication Year: 1996, Page(s):1320 - 1324 vol.3
    Cited by:  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (544 KB)

    A new direct sequence spread spectrum scheme for ISM band radio local area networks using BPSK modulation and matched filter receivers is presented. It employs an optimised 22-chip sequence whose two 11-chip segments are alternately used as spreading sequences for adjacent symbols. Owing to the low cross-correlation between the two 11-chip segments, the inter-symbol interference caused by long del... View full abstract»

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  • Adaptive dual-channel demodulation in CDMA mobile satellite systems

    Publication Year: 1996, Page(s):1315 - 1319 vol.3
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    In the following analysis, assuming a satellite DS-CDMA system for mobile communications, the performance degradation due to imperfect phase reference is investigated. It is assumed that a low percentage of the users of a satellite mobile system may have to front a more severe multipath environment. In a mobile radio system, the phase synchronisation can be a critical issue if the channel is affec... View full abstract»

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  • Neural network matched filter receivers for CDMA systems

    Publication Year: 1996, Page(s):1024 - 1028 vol.3
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (460 KB)

    A new receiver design using feed-forward artificial neural networks for efficient multi-user detection in CDMA systems is presented in this paper. The heart of the receiver is a special neural network, the neural matched filter (NMF), is trained not only to detect the spreading code of the assigned user but also to suppress the multiple-access interference caused by the waveforms of other users. T... View full abstract»

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  • Nonlinear correlator for DS/SSMA communications in impulsive channels

    Publication Year: 1996, Page(s):1043 - 1047 vol.3
    Cited by:  Papers (1)
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    A nonlinear correlator for the reception of multiple-access transmissions in impulsive channels is presented. In this detector, a practical performance measure, i.e., the output signal-to-noise ratio, for optimizing the nonlinearity is addressed and a learning algorithm is developed to adjust the nonlinearity in accordance with the noise characteristic. The performance in single- and synchronous t... View full abstract»

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  • Throughput density constraints for wireless LANs based on DSSS

    Publication Year: 1996, Page(s):1344 - 1350 vol.3
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    The throughput performance of wireless LANs can be characterized in various ways. The installation of wireless LANs and the positioning of access points will be based on requirements for throughput and coverage, while the cost of the access point infrastructure is important. This paper considers the critical parameters for wireless LANs that operate conform to the IEEE 802.11 DSSS (direct sequence... View full abstract»

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  • The improved data encryption standard (DES) algorithm

    Publication Year: 1996, Page(s):1310 - 1314 vol.3
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (472 KB)

    The cryptosystem which is most used throughout the world for protecting information is the Data Encryption Standard (DES) which was announced by the National Bureau of Standard (NBS). The DES must be stronger than the other cryptosystems in its security. But, because the process time required for cryptanalysis has lessened, and because hardware technique has developed rapidly, the DES may be attac... View full abstract»

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  • Efficient DSSS burst synchronization methods

    Publication Year: 1996, Page(s):1017 - 1023 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (528 KB)

    This paper treats the synchronization of packetized (burst like) direct sequence spread spectrum (DSSS) signals. Burst lengths up to 200 bits with binary phase shift keying (BPSK) modulation are considered. Under the condition of receive signal levels below the noise level this is a very critical enterprise as rapid burst detection and acquisition techniques are needed. Assuming that the pseudo no... View full abstract»

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  • Improvement of IS-95 by symbol splitting

    Publication Year: 1996, Page(s):1078 - 1081 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (340 KB)

    Symbol splitting is a time-diversity technique for DS-CDMA (direct sequence code division multiple access) mobile communication systems. Conventional systems transmit all chips belonging to one information symbol consecutively. Instead, symbol splitting combines some chips in groups which are interleaved and transmitted with appropriate time-spacing to achieve time-diversity. It was shown previous... View full abstract»

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  • Propagation of 450 MHz radio signals in a multi-floor building

    Publication Year: 1996, Page(s):1227 - 1233 vol.3
    Cited by:  Papers (1)
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    Radio local area networks (R-LAN) and personal communication networks (PCN) operating in the frequency range from 300 MHz to 3 GHz proposed for indoor communications, have significant advantages over conventional telephone networks. Radio propagation inside a building is a complex phenomenon due to presence of a large number of randomly distributed reflectors, scatterers and movement of people whi... View full abstract»

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  • Performance of pilot carrier based Doppler compensation for CDMA land mobile satellite links

    Publication Year: 1996, Page(s):1156 - 1161 vol.3
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (472 KB)

    The performance of a Doppler estimation scheme for CDMA land mobile LEO satellite systems under realistic channel conditions is studied by computer simulation. The scheme can be applied in Doppler compensation of the received signals, to aid in the code acquisition under the severe Doppler conditions offered by the satellite channel. The proposed scheme is based on a continuous-wave pilot carrier ... View full abstract»

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  • Application of the Prony algorithm to a predictive RAKE receiver

    Publication Year: 1996, Page(s):1039 - 1042 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (300 KB)

    The use of RAKE receivers in systems which are subject to rapidly fading multipath propagation requires an adaptive algorithm with a predictive element to avoid large errors due to phase lag. A novel use of Prony's (1795) method, as a predictive algorithm in RAKE receivers, is proposed, and its performance in terms of bit error rate evaluated using the COST 207 model of a typical urban environment... View full abstract»

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  • Protocol aspects of evolutionary CDMA schemes

    Publication Year: 1996, Page(s):1172 - 1177 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (528 KB)

    The permanently increasing demand for high rate data services in future mobile radio systems requires an air interface which fulfills these requirements. The well known mobile radio standard GSM has almost reached its limits, because it is mainly designed for voice services and a small number of fixed data services. The future mobile radio system which provides many different services at high data... View full abstract»

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  • Coded direct sequence spread spectrum systems over satellite channels using an adaptive receiver

    Publication Year: 1996, Page(s):940 - 944 vol.3
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (420 KB)

    This paper examines the performance of a direct sequence spread spectrum multiple access (DS-SSMA) system used over two typical, frequency-selective, fading channels for intermediate circular orbit (ICO) satellites. In an attempt to increase the system efficiency, a timing and phase synchronisation insensitive, adaptive receiver described by Rapajic and Vucetic (1994) has been implemented. The rec... View full abstract»

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  • An overview of forward error-correction coding for spread spectrum

    Publication Year: 1996, Page(s):1193 - 1197 vol.3
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    An overview of forward error-correction (FEC) coding for spread spectrum is given. The relations between FEC and spreading in spread spectrum are discussed. Some coding schemes such as convolutional coding, trellis coding and turbo coding for spread spectrum are compared. Finally, conclusions and future research topics are presented View full abstract»

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  • Derivation of the probability of packet success for asynchronous DS/CDMA using random periodic spreading sequences

    Publication Year: 1996, Page(s):1339 - 1343 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (476 KB)

    A method for deriving the probability of packet success of an asynchronous direct-sequence code-division multiple-access (DS/CDMA) system with random periodic spreading sequences is developed. Numerical results were obtained using Monte Carlo integration. It is shown, that a system employing random spreading codes performs considerably different than a system using random periodic spreading sequen... View full abstract»

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  • An efficient decoding technique for CDMA communication systems based on the expectation maximization algorithm

    Publication Year: 1996, Page(s):1305 - 1309 vol.3
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (352 KB)

    We present a computationally efficient algorithm for detection of superimposed signals in DS-CDMA communication systems. Using the EM algorithm we decompose the multiuser detection problem into a series of single user problems. The resultant structure includes the multistage detector of Varanasi et al. (1991) and the conventional single user detector (or linear decorrelator of Lupas et al. (1989))... View full abstract»

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  • Effects of channel distortion on code tracking error in DS spread spectrum systems

    Publication Year: 1996, Page(s):1012 - 1016 vol.3
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (424 KB)

    The delay locked loop tracking circuit of a typical direct sequence spread spectrum system has been analysed to find an analytical expression of the tracking error bias due to the presence of linear channel distortions, independently of their origin (for instance, due to band limitations and/or multipath propagation). Moreover, the influence of the tracking error on system performance, in terms of... View full abstract»

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  • Coherent demodulation for IS-95 uplink

    Publication Year: 1996, Page(s):1073 - 1077 vol.3
    Cited by:  Papers (9)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (500 KB)

    In the uplink of the IS-95 mobile communication standard, an orthogonal modulation scheme combined with binary convolutional coding and binary interleaving is defined. In Viterbi et al. (1993), a receiver with non-coherent demodulation is proposed for this transmission system. In this paper, a receiver with coherent demodulation and decision-directed channel estimation is introduced. Comparisons o... View full abstract»

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  • Channel characterisation for spread spectrum satellite communications

    Publication Year: 1996, Page(s):1221 - 1226 vol.3
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (556 KB)

    The paper examines the characteristics of satellite propagation channels for spread spectrum communications. Based on measurement campaigns at L-band, the signal bandwidth is determined when the channel becomes frequency-selective. A wideband channel model for land mobile satellite (LMS) services is presented which characterises the time-varying transmission channel between a satellite and a mobil... View full abstract»

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  • Parallel interference cancellation in multiuser detection

    Publication Year: 1996, Page(s):1151 - 1155 vol.3
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (400 KB)

    The parallel interference cancellation (PIC) principle is a conceptually simple and yet effective method of parameter estimation and data detection in the presence of multiple-access and multipath interference. It unifies some of the known methods of data detection, complex channel coefficient estimation, as well as delay tracking in DS-CDMA receivers. The PIC method will be derived and some numer... View full abstract»

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  • Influence of long code auto-correlation on RAKE reception performance in DS-CDMA mobile communications

    Publication Year: 1996, Page(s):1034 - 1038 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (448 KB)

    This paper investigates the influence of long codes on RAKE reception in DS-CDMA mobile radio communications. Conventional DS-CDMA mobile communication systems employ long codes in order to “whiten” the interference signals from other cells. The conventional long code randomizes not only the undesired signals but also the different delay components of the desired signal which, therefor... View full abstract»

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  • Selection of an optimal modulation scheme for digital communications over low voltage power lines

    Publication Year: 1996, Page(s):1087 - 1091 vol.3
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (488 KB)

    There is an ever increasing demand for environmental management of buildings, office automation, security monitoring or remote control of customer appliances and remote meter reading. The AC low voltage power line would be an ideal communications medium for digital data. Several systems for power line communications (PLC) were presented. The reliability of PLC is strongly influenced by time-varian... View full abstract»

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