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ERROR-PROBABILITY BOUNDS AND APPROXIMATIONS FOR DS SPREAD-SPECTRUM COMMUNICATION-SYSTEMS WITH multiple TONE OR multiple access INTERFERENCE

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IEEE TRANSACTIONS ON COMMUNICATIONS 1984年第5期32卷 493-502页

作者： DOU, RH MILSTEIN, LB CHONGQING INST POSTS & TELECOMMUN DEPT TELECOMMUN ENGNCHONGQINGPEOPLES R CHINA

Upper and lower bounds on the average probability of error of direct sequence (DS) spread-spectrum communication systems operating in the presence of either multiple tone or multiple access interference are presented. The bounds are quite tight and can be used without the restriction that the peak level of the interference be less than the desired signal level. A simple method for evaluating approximations to the bounds for multiple access systems, in which the peak interference does indeed exceed the desired signal level, is presented as well. The tightness of both the bounds and the approximations are illustrated with numerical results.

关键词： Error probability Spread spectrum communication multiple access interference Multiaccess communication Upper bound Phase shift keying Interference constraints AWGN Jamming direct-sequence code-division multiple access

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Hybrid ARQ scheme using interleaved Reed-Solomon codes in a power-controlled DS-CDMA cellular system

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IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 1996年第4期45卷 683-687页

作者： Yi, CH Lee, JH SEOUL NATL UNIV DEPT ELECT ENGNSEOUL 151742SOUTH KOREA

In this paper, a new hybrid automatic repeat request (ARQ) scheme is proposed for data transmission in a power-controlled direct sequence (DS) code division multiple access (CDMA) system cellular system, Data frame is composed of interleaved Reed-Solomon codes, The depth of interleaving is determined by a power-control interval, After decoding each codeword with algebraic decoding, the post-decoding processor decides whether to accept the codeword or to discard it by using channel state information from the power-control processor. The proposed hybrid ARQ scheme significantly reduces the probability of undetected error among accepted codewords without significantly reducing throughput.

关键词： Channel state information data transmission undetected error Throughput control interval direct-sequence code-division multiple access codeword Reed-Solomon codes Power control control processor data frames undetected error probability cellular system HARQ

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V2V Channels and Performance of Multiuser Spread Spectrum Modulation

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IEEE VEHICULAR TECHNOLOGY MAGAZINE 2007年第4期2卷 19-25页

作者： Sen, Indranil Matolak, David W. Ohio Univ Athens OH 45701 USA

Vehicle-to-vehicle (V2V) communications have drawn much attention in recent years. In this article, we discuss tradeoffs between implementation complexity and accuracy of several stochastic channel models for the V2V environment, and then address spread-spectrum system performance attained using these channel models. Two different propagation environments are considered: urban and open areas (highways). The necessity of employing nonstationary channel models to accurately represent the channel is substantiated by comparing stationary and nonstationary empirical model outputs with measured data. A framework to compare single-carrier direct sequence code division multiple access (SC-DS-CDMA) and multicarrier DS-CDMA (MC-DS-CDMA) performance in V2V channels is presented, and bit error ratio (BER) performance of the schemes is provided for the two channels. Our comparison of single-and multi-user performance shows that MC-DS-CDMA performs better than SC-DS-CDMA in both V2V environments.

关键词： Spread spectrum communication System performance Multiaccess communication AWGN Intelligent transportation systems Communication standards direct-sequence code-division multiple access Frequency Rayleigh channels Power system modeling

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Performance Analysis of SC DS-CDMA and MC DS-CDMA Systems over Nakagami-m Fading Channel

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IETE TECHNICAL REVIEW 2007年第4期24卷 323-330页

作者： Anuradha, S. Srigowri, S. Krishna, K. S. Rama Reddy, K. V. V. S. VRS Engn Coll Dept ECE Vijayawada 520007 India Andhra Univ Coll Engn Dept ECE Vishakhapatnam 530003 Andhra Pradesh India

This paper deals with simulation of Nakagami-m fading in wireless channels using generalized SC DS-CDMA and MC DS-CDMA schemes using binary phase shift keying modulation scheme. The paper proposes for deriving Bit Error Rate (BER) in BPSK-SC DS-CDMA and MC DS-CDMA systems over Nakagami-m fading channels. The numerical results are plotted as BER vs SNR for various values of Nakagami factor m, number of users K and jamming interference (JSR) using MAT LAB software. The performance of Nakagami-m channel using BPSK-SC DS-CDMA and MC DS-CDMA techniques are compared. It is observed that there is a decrease in Bit Error Rate for increase in m for SC DS-CDMA and MC DS-CDMA. The number of users k, JSR increases as Bit Error Rate increases for MC DS-CDMA. For the same values of m BER for MC DS-CDMA is smaller when compared with SC DS-CDMA using Maximal Ratio Combining (MRC) diversity technique.

关键词： direct-sequence code-division multiple access Scandium Fading channels CDMA mobile communications

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On the outage behaviour of large DS-CDMA systems with LMMSE detection

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EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 2006年第2期17卷 245-255页

作者： Prätor, O Fettweis, GP Dresden Univ Technol Vodafone Chair Mobile Commun Syst D-01062 Dresden Germany

The outage behaviour of the single cell DS-CDMA uplink is investigated for flat Rayleigh fading channels. Goal of the work is to find an analytical way for the optimisation of the system spectral efficiency under some outage probability constraint by adjusting parameters such as modulation, spreading factor, code rate and number of codes per user. Therefore, the results of the asymptotic analysis for large CDMA systems with random spreading codes are used to obtain the signal-to-interference-and-noise ratio after the linear minimum mean-squared-error detector. This information is then deployed to characterise the system performance using bounds of the information theory. First, the ergodic behaviour is investigated with respect to the spectral efficiency for both coding at capacity and discrete modulation and coding at cut-off rate. Then, the outage probability is defined and studied for coding at capacity. The influence of the system load on the outage is determined analytically and compared to simulation results. Afterwards, the impact of modulation and coding at cut-off rate on the outage behaviour is considered. An expression is presented that allows to easily determine the additional required signal-to-noise ratio for modulation and coding at cut-off rate from the capacity results. Finally, the investigations are extended to determine the maximum system spectral efficiency under given outage constraints. The optimum system loads corresponding to the maximum efficiencies are presented and shown to vary for the different modulation schemes. Copyright (C) 2006 AEIT.

关键词： spectral efficiency coding direct-sequence code-division multiple access CDMA mobile communications maximum efficiency Rayleigh fading System performance signal to noise ratios adjustable parameter

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Wavelet based multi-chip rate diret sequence code division multiple access

Wavelet based multi-chip rate diret sequence code division m...

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IEEE Signal Processing and Communications Applications (SIU)

作者： E. Ozturk O. Kucur Elektronik Mühendislği Bölümü Zonguldak Karaelmas Üniversitesi Zonguldak Turkey Elektronik Mühendislği Bölümü Gebze Yüksek Teknoloji Enstitüsü Kocaeli Turkey

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Reliable hybrid ARQ data transmission with optimal signal-to-interference ratio assignment in CDMA PCS

Reliable hybrid ARQ data transmission with optimal signal-to...

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IEEE International Conference on Universal Personal Communications (ICUPC 98)

作者： Sun, SS Krzymien, W Krenz, R Jalali, A Univ Alberta TR Labs Edmonton AB Canada

ISBN: (纸本)0780351061

Combined error correction and detection techniques, or hybrid automatic-repeat-request (ARQ) schemes with negative acknowledgment are considered for highly reliable reverse link data transmission in direct sequence code division multiple access (DS-CDMA) personal communication systems. In this paper a coherent link using OQPSK and continuous pilot signal assisted radio channel estimation is analyzed. The proposed selective repeat hybrid ARQ scheme employs an inner convolutional code for error correction and an outer shortened BCH code for error detection. Accepted packet error rate and throughput are derived as a function of the error correction encoded frame error rate. An optimum signal-to-interference ratio (SIR) assignment maximizing the system's capacity is also found. Analysis and simulations show that by applying the proposed type I hybrid ARQ scheme with properly selected system parameters, virtually error free and highly efficient data transmission in CDMA personal communication systems is possible.

关键词： Automatic repeat request Channel estimation Convolutional codes Data communication direct-sequence code-division multiple access Error analysis Error correction codes Multiaccess communication Signal analysis Throughput

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System-Level Throughput of Non-orthogonal access with SIC in Cellular Downlink When Channel Estimation Error Exists 79

System-Level Throughput of Non-orthogonal Access with SIC in...

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IEEE 79th Vehicular Technology Conference (VTC-Spring)

作者： Yamamoto, Kenta Saito, Yuya Higuchi, Kenichi Tokyo Univ Sci Grad Sch Sci & Technol Tokyo 162 Japan NTT DOCOMO INC Radio Access Network Dev Dept London England

ISBN: (纸本)9781479944828

We investigate the influence of channel estimation error on the achievable system-level throughput performance of non-orthogonal access with successive interference cancellation (SIC) in the cellular downlink. The channel estimation error in non-orthogonal access causes residual interference in the SIC process, which decreases the achievable user throughput. Furthermore, the channel estimation error causes error in the transmission rate control for the respective users, which may result in decoding error at not only the destination user terminal but also other user terminals for SIC. However, we show that by using a simple transmission rate back-off algorithm, the impact of the channel estimation error is effectively alleviated and non-orthogonal access with SIC achieves clear average and cell-edge user throughput gains relative to orthogonal access similar to the case with perfect channel estimation.

关键词： cellular radio channel estimation code division multiple access error analysis interference suppression SIC process cell-edge user throughput gains cellular downlink channel estimation error exists decoding error destination user terminal direct sequence-code division multiple access nonorthogonal access residual successive interference cancellation system-level throughput performance transmission rate control back-off algorithm Base stations Channel estimation Decoding Downlink Interference Silicon carbide Throughput channel estimation direct-sequence code-division multiple access Downlink Throughput non-orthogonal code division multiple access BASE STATION cellular radio suppression of interference DECODING Error analysis SILICON CARBIDE

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Interference suppression for spatial-temporal propagation parameter identification in wireless communications

Interference suppression for spatial-temporal propagation pa...

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International Conference on Communications, Circuits and Systems

作者： Ristaniemi, T Wu, R Tampere Univ Technol Inst Commun Technol FIN-33101 Tampere Finland

ISBN: (纸本)0780386477

In this paper Independent Component Analysis (ICA) is considered for code timing and direction-of-arrival (DOA) estimation, here called two-dimensional code acquisition, in a direct sequence spread spectrum communication system utilizing antenna arrays. A new method named as independent component analysis frequency selection (ICA-FS) is used to perform interference suppression before parameter estimation as to decrease parameter estimation error. It requires a training sequence corresponding to the desired user to be known, and data signals corresponding to different users to be statistically independent.

关键词： direction-of-arrival estimation spread spectrum communication code division multiple access delay estimation interference suppression independent component analysis array signal processing spatial-temporal propagation parameter identification wireless communications independent component analysis frequency selection code timing estimation DOA estimation two-dimensional code acquisition direct sequence spread spectrum communication system antenna arrays parameter estimation error training sequence time delay estimation DS-CDMA direction of arrival estimation suppression of interference delay estimation CARRIER SYSTEM training sequence Antenna arrays code division multiple access Spread spectrum communication array signal processing Parameter estimation direct-sequence code-division multiple access direct sequence spread spectrum communication

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A transmit diversity scheme using space-time spreading for DS-CDMA systems in Rayleigh fading channels 62

A transmit diversity scheme using space-time spreading for D...

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62nd IEEE Vehicular Technology Conference

作者： Hamouda, W Aljerjawi, M Concordia Univ Dept Elect & Comp Engn Montreal PQ HEG 1M8 Canada

ISBN: (纸本)0780391527

The application of space-time block coding (STBC) in the downlink of a communication system has shown to improve the quality of the received signal at the mobile user by placing the spatial diversity at the base station. In this paper, we propose a simple space-time spreading scheme for code-division multiple-access (CDMA) systems over fast-fading channels. The proposed transmit diversity scheme is based on two transmit and one receive antenna and is suitable for Rayleigh fast-fading channels. In this we employ orthogonal spreading codes to exploit the time diversity introduced by the channel, and hence a two-fold of the diversity order obtained using existing space-time spreading schemes is achieved. Nevertheless, for slowly-fading channels, we show that the proposed coding scheme reduces to existing schemes introduced in the literature with no performance degradation. Finally, we examine the effect of using nonorthogonal spreading codes on the receiver performance. Our results show that using a simple adaptive decoder, based on the minimum mean-squared error (MMSE) criterion, the diversity order is still maintained and only a small loss in the signal-to-noise ratio is incurred relative to the ideal case with orthogonal codes.

关键词： transmit diversity maximal-ratio combining fast-fading direct-sequence code-division multiple access

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