检索结果-内蒙古大学图书馆

BER performance comparison of single code and multicode DS/CDMA channelization schemes for high rate data transmission

引用

IEEE COMMUNICATIONS LETTERS 2001年第2期5卷 67-69页

作者： Zhang, R Tjhung, TT Zhang, HB He, P Natl Univ Singapore Dept Elect & Comp Engn Singapore 119260 Singapore Ctr Wireless Commun Singapore 117674 Singapore Inst Microelect Singapore 117674 Singapore

The bit-error-rate (BER) performance of single code and multicode channelization schemes for high rate data transmission in direct-sequence code-division-multiple-access (DS/CDMA) systems is compared in this letter. The multipath interference (MPI) effects, which become significant as the data rate increases, are accurately included in the analysis, It is shown that notable performance improvement can be achieved by using multi-code scheme in the multipath fading channel.

关键词： BER performance DS/CDMA multicode RAKE receiver

来源：评论

学校读者我要写书评

暂无评论

Cellular multicode CDMA capacity with SIR-based power control in a multipath fading environment

Cellular multicode CDMA capacity with SIR-based power contro...

引用

15th IEEE International Symposium on Personal, Indoor, Mobile, Radio Communications (PIMRC 2004)

作者： Téllez-Labao, C Romero-Jerez, JM Ruiz-García, M Univ Malaga ETSI Telecomunicac Dept Tecnol Elect E-29071 Malaga Spain

ISBN: (纸本)0780385233

In this paper, the reverse link capacity is analysed for a multicode direct sequence-code division multiple access (multicode DS/CDMA) system with SIR-based power-control in a multiple-cell environment. Mean and variance statistics of total interference power are derived in order to investigate the effect of two important factors on capacity: 1) the required signal to interference ratio (SIR) and 2) the required number of codes, for each type of user. Unlike most previous works related to SIR based power control, the effect of multipath fading is explicitly accounted for and mobiles are assumed to connect to the base station whose pilot signal is received with the highest power.

关键词： multicode CDMA power control target SIR

来源：评论

学校读者我要写书评

暂无评论

On codes with low peak-to-average power ratio for multicode CDMA

On codes with low peak-to-average power ratio for multicode ...

引用

IEEE International Symposium on Information Theory

作者： Paterson, KG Hewlett Packard Labs Bristol BS34 8QZ Avon England

ISBN: (纸本)0780375017

Codes which reduce the peak-to-average power (PAPR) in multicode code-division multiple-access (MC-CDMA) communications systems,are systematically studied. The problem of designing such codes is reformulated as a new coding-theoretic problem: codes with low PAPR are ones in which the codewords are far from the first-order Reed-Muller code. Bounds on the tradeoff between rate, PAPR, and error-correcting capability of codes for MC-CDMA follow. The connections between the code design problem, bent functions, and algebraic coding theory (in particular, the Kerdock codes and Delsarte-Goethals codes) are exploited to construct code families with flexible parameters for the small values of n of practical interest. In view of their algebraic structure, these codes enjoy efficient encoding and decoding algorithms. The correspondence concludes by listing open problems in algebraic coding theory and Boolean functions motivated by the correspondence.

关键词： Bent function code-division multiple access (CDMA) envelope Kerdock multicode power rate adaptation Reed-Muller codes Walsh-Hadamard transform

来源：评论

学校读者我要写书评

暂无评论

Quaternary Constant-Amplitude Codes for multicode CDMA

Quaternary Constant-Amplitude Codes for Multicode CDMA

引用

IEEE International Symposium on Information Theory

作者： Schmidt, Kai-Uwe Tech Univ Dresden Commun Lab D-01062 Dresden Germany

ISBN: (纸本)1424414296

A constant-amplitude code is a code that reduces the peak-to-average power ratio (PAPR) in multicode code-division multiple access (MC-CDMA) systems to the favorable value 1. In this paper, quaternary constant-amplitude codes (codes over Z(4)) of length 2(m) with error-correction capabilities are studied. These codes exist for every positive integer in, while binary constant-amplitude codes cannot exist if in is odd. Every word of such a code corresponds to a function from the binary m-tuples to Z(4) having 2 the bent property, i.e., its Fourier transform has magnitudes 2(m/2). Several constructions of such functions are presented, which are exploited in connection with algebraic codes over Z(4) (in particular quaternary Reed-Muller, Kerdock, and Delsarte-Goethals codes) to construct families of quaternary constant-amplitude codes. Mappings from binary to quaternary constant-amplitude codes are presented as well.

关键词： Bent function code code-division multiple access (CDMA) Delsarte-Goethals Kerdock multicode peak-to-average power ratio (PAPR) quaternary Reed-Muller

来源：评论

学校读者我要写书评

暂无评论

Performance of Wavelet Packets Based Multicarrier multicode CDMA Communication System in the Presence of Narrowband Jamming

Performance of Wavelet Packets Based Multicarrier Multicode ...

引用

1st International Conference on Communications, Signal Processing, and their Applications (ICCSPA)

作者： Akho-Zahieh, Maryam Saleh, Khalil Abdellatif, Nasser Appl Sci Private Univ Elect & Comp Engn Dept Amman 11931 Jordan

ISBN: (纸本)9781467328210;9781467328203

In this paper, the performance of multicarrier (MC), multicode (MCD), code division multiple access (CDMA) system employing wavelet packets (WPs) for modulation in the presence of narrowband jamming is investigated. The system's performance is evaluated by means of bit error rate (BER) and outage probability (P-out). The effects of channel intensity profile, type of wavelet families and their filters length, number of superstreams of wavelets and number of substreams on the system performances were investigated by means of analytical methods and numerical results. Also, the performance of the system is compared to that of MC/MCD-CDMA based on sinusoidal carrier. Results reveal considerable performance improvement of MC/MCD-CDMA system based on WPs carrier over the system based on sinusoidal carrier.

关键词： Wavelet packets multicarrier multicode narrow-band jamming

来源：评论

学校读者我要写书评

暂无评论

Optimal power distribution control under different total power constraint strategies for multicode MC-CDMA with zero-forcing successive interference cancellation

Optimal power distribution control under different total pow...

引用

IEEE Wireless Communications and Networking Conference

作者： Tan, M Bar-Ness, Y New Jersey Inst Technol Dept ECE CCSPR Newark NJ 07102 USA

ISBN: (纸本)0780383443

multicode multi-carrier CDMA (MC-CDMA) is a promising candidate for supporting multimedia services in future wireless communications. However, the performance of this system is limited by self-interference (SI) and multi-user interference (MUI). To mitigate this problem, a nonlinear zero-forcing successive interference cancellation (ZF-SIC) receiver is applied in this paper. Furthermore, to minimize each user's bit error rate (BER), optimal power distribution control (PDC) is considered. Results show that in correlated Rayleigh fading channels, the multicode MC-CDMA system based on the ZF-SIC receiver with it optimal PDC remarkably outperforms other receivers proposed in the literature. Moreover, the ZF-SIC integrated with the optimal PDC present significant performance advantage over that with the equal BER PDC, particularly tinder a short-term total transmit power constraint.

关键词： multicode MC-CDMA ZF SIC power distribution control (PDC)

来源：评论

学校读者我要写书评

暂无评论

Equal BER power distribution control for multicode MC-CDMA with MMSE successive interference cancellation

Equal BER power distribution control for multicode MC-CDMA w...

引用

IEEE International Conference on Communications (ICC 2004)

作者： Tan, MZ Bar-Ness, Y New Jersey Inst Technol ECE Dept Ctr Commun & Signal Proc Res Newark NJ 07102 USA

ISBN: (纸本)0780385330

multicode multi-carrier CDMA (MC-CDMA) is a promising candidate for supporting multimedia services in future wireless communications. However, the performance of this system is limited by self-interference (SI) of user's multicodes and multi-user interference (MUI). In this paper, to mitigate this problem, a minimum mean square error successive interference cancellation (MMSE-SIC) receiver is applied in multicode MC-CDMA. Furthermore, to increase the efficiency of SIC, a simple power distribution control (PDC) algorithm, based on equal BER criterion, is investigated under a short-term constraint of average transmit power. In correlated Rayleigh fading channels, the MMSE-SIC receiver integrated with the equal BER PDC can suppress interference effectively, resulting in a performance close to the single user bound (SUB).

关键词： multicode MC-CDMA MMSE SIC equal BER power distribution control (PDC)

来源：评论

学校读者我要写书评

暂无评论

A Mnemonic Multiuser Detector Based on Genetic Algorithm in multicode LAS-CDMA System

A Mnemonic Multiuser Detector Based on Genetic Algorithm in ...

引用

5th International Conference on Wireless Communications, Networking and Mobile Computing

作者： Liao, Hancheng Jiangxi Univ Finance & Econ Sch Elect Nanchang 330013 Peoples R China

ISBN: (纸本)9781424436927

Multiple access interference still exists in large-area-synchronized code division multiple access (LAS-CDMA) system when the LAS multicode is implemented. The generation of spreading sequences is given. Genetic algorithm (GA) is often used to get the multiuser detection (MUD) gain and its computational complexity is much less than that of the optimum maximum-likelihood (ML) detectior. In order to further enhance the detection performance, a type of mnemonic GA detector based on the basic GA method is studied, where a replacement strategy of modified elitism is utilized. Simulation results shows that GA detector with memory can obviously reduce the number of iterations in the recursive process.

关键词： LAS-CDMA multicode Genetic Algorithm Multiuser Detector

来源：评论

学校读者我要写书评

暂无评论

Frequency-domain Soft Interference Cancellation for multicode CDMA Transmissions

Frequency-domain Soft Interference Cancellation for Multicod...

引用

63rd IEEE Vehicular Technology Conference

作者： Ishihara, Koichi Takeda, Kazuaki Adachi, Fumiyuki Tohoku Univ Dept Elect & Commun Engn Grad Sch Engn Sendai Miyagi 980 Japan

ISBN: (纸本)9780780393912

Frequency-domain equalization (FDE) based on minimum mean square error (MMSE) criterion can significantly improve the BER performance of DS- and MC-CDMA signal transmissions in a severe frequency-selective fading channel. However, since the frequency-distorted signal cannot be completely equalized, the residual inter-code interference (ICI) limits the BER performance improvement. In 4G systems, much higher variable rate data services than in the present 3G systems are required. Orthogonal multicode transmission technique has flexibility in offering variable rate services. However, the BER performance degrades as the number of parallel codes increases. In this paper, we propose a frequency-domain soft interference cancellation (FDSIC) for multicode DS- and MC-CDMA signal transmissions and their achievable BER performances are evaluated by computer simulation.

关键词： DS-CDMA MC-CDMA Frequency-domain equalization(FDE) multicode Interference cancellation

来源：评论

学校读者我要写书评

暂无评论

Optimum modulation and multicode formats in CDMA systems with multiuser receivers

Optimum modulation and multicode formats in CDMA systems wit...

引用

20th Annual Joint Conference of the IEEE-Computer-Society/IEEE-Communication-Society

作者： Ulukus, S Biglieri, E Win, MZ AT&T Labs Res Hoboken NJ USA

ISBN: (纸本)0780370163

We study the problem of maximizing the total system throughput under a bit error rate constraint for all users in the uplink of a single-cell synchronous CDMA system. Users realize variable bit rates by using a combination of multicode transmission and adaptive QAM modulation. We assume random signature sequences for all users, and perform an asymptotic analysis. We parametrize each user's resource allocation scheme by two parameters, viz., the number of signatures the user transmits with and the number of signal points in the user's QAM constellation, and optimize the total throughput over this parameter space. We examine four different settings: single-user matched filter (SUMF) and minimum-mean-square error (MMSE) receiver at the base station, with and without maximum-power constraints. For a single user system, we describe the jointly optimum number of multicodes and constellation sizes for these four different system models. When multiple users are present, we show that the total throughput is maximized when only one user transmits: with no maximum power constraints this user can be chosen arbitrarily, otherwise it should be the one with the largest SNR. This solution, although optimal in the sense of maximizing the total throughput, is unfair to all but one user: thus, we examine a scheduling mechanism that assigns equal time frames to all users, thus yielding maximum fairness, and discuss the resulting total throughput loss.

关键词： CDMA adaptive modulation multicode throughput maximization power control MMSE

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：