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1.
本文提出了一种通用的自适应编码调制系统吞吐量性能分析方法.基于各固定编码调制方式的误码率(BER)性能,使每种编码调制方案对应于一个信道平均信噪比(SNR)范围,再应用拉格朗日函数法得到使自适应编码调制系统吞吐量性能最大的信噪比转换门限,可得到系统的平均吞吐量性能.数值分析结果表明,相对于自适应M进制正交幅度调制(MQAM),自适应Turbo编码MQAM系统吞吐量性能有显著提高,并且该性能受瞬时误码率要求的影响较小.Nakagami信道中,在相同平均信道信噪比条件下,随着m的增大,系统吞吐量性能提高缓慢. 相似文献
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Performance Evaluation for Forward-Link Cellular DS-CDMA over Frequency-Selective Nakagami Multipath Fading Channels 总被引:1,自引:1,他引:0
The bit-error rate (BER) for a forward-link cellulardirect-sequence code-division multiple-access (DS-CDMA) systemis evaluated. This analysis takes into account the effects ofmulti-cell interference resulting from Nakagami multipath fading,frequency selectivity, path loss and mobile user spatialdistribution. Exponentially decaying multipath intensityprofile (MIP) is adopted in the model to investigate itssignificance on the overall performance. In order to evaluatethe BER performance efficiently, saddlepoint integration (SPI)is applied in the analysis. By fixing the number of resolvablemultipaths and varying the number of fingers for the RAKEreceiver, it can be shown that the capacity of a DS-CDMAcellular system increases almost linearly with the number ofRAKE fingers. 相似文献
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基于Alamouti提出的BPSK调制下空时分组码在Rayleigh衰落信道中的简单分集方案。推导出多发射和多接收天线系统中正交空时分组码在Nakagami衰落信道的BPSK调制下的比特差错率的最小距离球界,并推广到在高阶调制下衰落信道中系统符号差错率的性能。仿真分析和比较了空时分组码的多天线系统中发射和接收天线分集增益,以及信道相关参数的变化对系统误比特性能的影响。 相似文献
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In this paper, the capacity and error probability of maximal ratio combining (MRC) reception are considered for different
modulation schemes over correlated Nakagami fading channels. Based on an equivalent scalar additive white Gaussian noise (AWGN)
channel, we derive the characteristic function (CF) and the probability density function (PDF) of the signal to noise ratio
for MRC reception over Nakagami fading channels. Using these CF and PDF results, closed form error probability and capacity
expressions are obtained for PSK, PAM and QAM modulation.
Wei Li received his Ph.D. degree in Electrical and Computer Engineering from the University of Victoria in 2004. He is now a Post-doctoral
Research Fellow in the Department of Electrical and Computer Engineering at the University of Victoria. He is a Member of
the IEEE. His research interests include ultra-wideband system, spread spectrum communications, diversity for wireless communications,
and cellular communication systems.
Hao Zhang was born in Jiangsu, China, in 1975. He received his Bachelor Degree in Telecom Engineering and Industrial Management from
Shanghai Jiaotong University, China in 1994, his MBA from New York Institute of Technology, USA in 2001, and his Ph.D. in
Electrical and Computer Engineering from the University of Victoria, Canada in 2004. His research interests include ultra-wideband
radio systems, MIMO wireless systems, and spectrum communications. From 1994 to 1997, he was the Assistant President of ICO(China)
Global Communication Company. He was the Founder and CEO of Beijing Parco Co., Ltd. from 1998 to 2000. In 2000, he joined
Microsoft Canada as a Software Engineer, and was Chief Engineer at Dream Access Information Technology, Canada from 2001 to
2002. He is currently an Adjunct Assistant Professor in the Department of Electrical and Computer Engineering at the University
of Victoria.
T. Aaron Gulliver received the Ph.D. degree in Electrical and Computer Engineering from the University of Victoria, Victoria, BC, Canada in
1989. From 1989 to 1991 he was employed as a Defence Scientist at Defence Research Establishment Ottawa, Ottawa, ON, Canada.
He has held academic positions at Carleton University, Ottawa, and the University of Canterbury, Christchurch, New Zealand.
He joined the University of Victoria in 1999 and is a Professor in the Department of Electrical and Computer Engineering.
He is a Senior Member of the IEEE and a member of the Association of Professional Engineers of Ontario, Canada. In 2002, he
became a Fellow of the Engineering Institute of Canada. His research interests include information theory and communication
theory, algebraic coding theory, cryptography, construction of optimal codes, turbo codes, spread spectrum communications,
space-time coding and ultra wideband communications. 相似文献
5.
Yang Yawpo Jong Shu-Li Liu Ji-Chyun Liu Ching-Hwa 《Wireless Personal Communications》2003,27(3):247-265
In this paper, effects of carrier frequency offset on performance of uplink MC-CDMA (Multi-Carrier Code Division Multiple
Access) system in Nakagami fading channel are investigated through the theoretical analysis and Monte Carlo computer simulations.
Both perfect maximal-ratio combining (MRC) and equal gain combining (EGC) receivers are analyzed; the impact of imperfect
channel fading estimation on the performance of MRC is also explored. The performance of MC-CDMA system is also compared with
that of the conventional single-carrier DS-CDMA system. Our results indicate that the performance of MC-CDMA system is sensitive
to even small values of carrier frequency offset and that the performance of MC-CDMA system improves as number of subcarriers
increases. In perfect channel fading estimation, the overall performance of MRC is superior to EGC. However, when imperfect
or inaccurate channel fading estimation exists, which leads to serious performance degradation, EGC becomes superior to MRC.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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在移动通信系统中,由于无线时变衰落信道的特点,使通信过程存在大量的不确定性,自适应方式在信道条件好时提高了传输速率或减小发送功率,在信道条件差时降低了速率或增大功率。通过仿真结果证明,根据信道的优劣情况进行自适应调制的系统在保持较低的误码率性能的同时,能提高了系统的传输速率,从而增强传输的可靠性并可提高频带利用率。 相似文献
7.
In this paper, blind adaptive multiuser detection (MUD) technique is developed for uplink transmission in multiuser space
diversity DS-CDMA system to overcome multipath fading effect and multiple access interference. The system consists of a space
diversity, a precombining blind adaptive detector (PBAD), and a weight adaptation technique based on the minimization of the
mean output energy (MOE). The bit error rate (BER) performance of this receiver for asynchronous DS-CDMA signals with independent
and correlated antenna branches under Nakagami fading channel for BPSK system is evaluated. It has been seen that the use
of antenna diversity can yield substantial improvement in performance even if the correlation between the antenna elements
is relatively large (up to 0.795). However, the large correlation values pose a significant reduction in the diversity gain
in comparison with the zero correlation situation. It has also been confirmed by simulations that the PBAD provides a significant
receiver performance in comparison with the RAKE receiver employing antenna diversity.
Khodr A. Saaifan Born in lebanon 1978, received B.S.c. degree in electrical and electronics engineering (with honors) from Benha higher institute
of technology, Benha, Egypt, in 2001, and the M.S.c. degree in communications from Cairo University, Giza, Egypt, in 2005.
He is currently pursuing for the Ph.D. degree at the Cairo University. His current research interest includes space–time-coded
transmission, multiple-input multiple-output (MIMO) systems, fading channels, equalization, turbo (iterative) processing,
and wideband code division multiple access (WCDMA).
Emad K. Al-Hussaini received his B.Sc degree in Electrical Communication Engineering from Ain-Shams University, Cairo, Egypt, in 1964 and his
M.Sc and Ph.D. degrees from Cairo University, Giza, Egypt, in 1974 and 1977, respectively. From 1964 to 1970, he was with
the General Egyptian Aeroorganization. Since 1970, he has been with the Department of Electronics and Communications, Faculty
of Engineering, Cairo University, and is currently professor there. He was a research fellow at Imperial College, London,
UK, and at the Moore School of Electrical Engineering, University of Pennsylvania, Philadelphia, PA, USA, in the academic
years 1976/1977 and 1981/1982, respectively. In 1990, he received the Egyptian national encouragement award for outstanding
engineering research. He has written several papers for technical international journals and conferences. His research interests
include signal processing, fading channel communication, modulation, and cellular mobile radio systems. Dr Al-Hussaini is
a senior member of IEEE. He is listed in Marquis Who's Who in the World and in the IBC (International Biographical Center,
Cambridge) for outstanding people of the 20th century. 相似文献
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调制方式的识别对于通信信号分析有着重要的作用。在现有有关调制识别的研究中,大部分都考虑的是加性高斯白噪声理想信道(AWGN)。文中通过仿真分析A.K.Nandi和E.E.Azzouz提出的数字调制识别算法(DMRAs)在衰落信道中的性能,详细研究了衰落信道特性对调制识别的影响。最后,得出了一些具有规律性的结论,对进一步深入研究衰落信道中调制识别技术具有一定的指导意义。 相似文献
10.
相关衰落信道上广义矩形MQAM的性能 总被引:2,自引:2,他引:0
研究相关多输入多输出Nakagami衰落信道上的正交空时分组编码广义矩形M进制正交幅度调制(MQAM)方案,使用矩生成函数方法推导其平均误符号率(SEP)的精确闭合表达式。比较了独立同分布Nakagami衰落信道上和相关Nakagami衰落信道上广义矩形MQAM的平均SEP性能。数值计算结果阐明Nakagami衰落系数和天线间的相关性对正交空时分组编码广义矩形MQAM平均SEP性能的影响。 相似文献
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In this paper, a novel trellis‐coded spatial modulation (TCSM) design method is presented and analyzed. Inspired by the key idea of trellis‐coded modulation (TCM), the detailed analysis is firstly provided on the unequal error protection performance of spatial modulation constellation. Subsequently, the Ungerboeck set partitioning rule is proposed and applied to develop a general method to design the novel TCSM schemes. Different from the conventional TCSM approaches, the novel one based on the Ungerboeck set partitioning rule has similar properties as the classic TCM, which has simple but effective code design criteria. Moreover, the novel designed schemes are robust and adaptive to the generalized Rician fading channels, which outperform the traditional TCSM ones. For examples, the novel 4‐, 8‐, and 16‐state TCSM schemes are constructed by employing different transmit antennas and different modulation schemes in different channel conditions. Simulation results clearly demonstrate the advantages of the novel TCSM schemes over the conventional ones. 相似文献
14.
在简述了Ka-波段星-地链路雨衰的特点及诸多抗雨衰对策的基础上,选取了两种常用的调制方式:MQAM(M维正交幅度调制)和MPSK(M维载波相位调制)分别进行研究比较,以获得不同的衰耗门限和雨衰条件下的相对较好的调制方式适应抗雨衰的要求。 相似文献
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Maximum Log-Likelihood Function-Based QAM Signal Classification over Fading Channels 总被引:3,自引:0,他引:3
Yang Yawpo Chang Jen-Ning Liu Ji-Chyun Liu Ching-Hwa 《Wireless Personal Communications》2004,28(1):77-94
In this paper, we propose a modulation classification algorithm for M-ary QAM signals in Rician and Rayleigh fading channels. The developed algorithms are based on the maximum log-likelihood functions, which are derived from received signals. First of all, we derived the amplitude PDF of M-ary QAM signal over flat and slowly Rayleigh and Rician fading channel, then we developed the log-likelihood functions and then the decision functions for classification. To demonstrate the performance of the proposed classifier, we give an example to classify the 16/32 QAM signals. Results indicate that the performance of classifier is heavily dependent on the severity of channel fading. When channel is AWGN, which means that there exists only one path (may be specular path) between transmitter and receiver, and the Rician factor k, approaches infinity in this case, henceforth, the performance is the best. The performance, however, is degraded with the decrease of k, and finally the classifier performs worst when channel becomes Rayleigh. Further performance improvement can be achieved by increasing the length of record. 相似文献
18.
推导m为整数的任意相关Nakagami-m衰落信道上采用最大比合并(MRC)分集接收和相干检测的差分编码四相相移键控(DE-QPSK)调制的平均误符号率(SER)精确表达式,并利用高斯Q函数指数形式的近似表达式推导相关Nakagami-m衰落信道上采用MRC分集接收的DE-QPSK调制的平均SER近似表达式。计算机仿真结果验证了精确理论分析的正确性和近似分析的准确性。 相似文献
19.
本文提出一种适用于多径频率选择性衰落信道中多用户OFDM系统的自适应分配算法.算法根据信道瞬时估计值,自适应地为多用户分配子信道和传输比特数,在给定误比特率的条件下,使系统总的发送功率达到最小.作者根据时分复用的基本思想,提出多用户最佳子信道和比特分配算法,导出系统最小发送功率的下限,并在此基础上,进一步提出次佳自适应分配算法.数值模拟表明:次佳算法所需的发送功率比下限值高约1dB;与等比特分配方案相比自适应分配算法可节省功率约3-4dB;与静态信道分配方案相比,自适应分配算法可节省功率6-8dB. 相似文献