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1.
This paper investigates the performance of a new Turbo Trellis Coded Modulation scheme over correlated flat fading channels
with channel interleaving. The novelty of the scheme is based on the application of a new modified transition metric incorporated
in the symbol-by-symbol MAP algorithm. We consider frequency non-selective, slow Rayleigh fading channels. Extensive simulation
results together with EXIT chart analysis show that the proposed scheme achieves better performance compared to the conventional
transition metric when channel state information is not available at the decoder.
Kostas V. Koutsouvelis was born in Thessaloniki, Greece, on July 16,1970. He received the degree Diploma in Electrical Engineering from Aristotle
University of Thessaloniki, Greece in 1996 and the Master degree in Satellite Communications Engineering from University of
Surrey in 1997.
From 1998 to 2003 he was involved in the development of V5.2 interface as a senior software designer in Intracom plc. In 2004
joined the research and development division of Hellenic Telecommunication Organization (OTE) and his also PhD candidate at
Aristotle University of Thessaloniki working with Turbo codes and Turbo Coded Modulation.
Christos E. Dimakiswasborn in Serres, Greece, on July 27, 1955.He received the degree Diploma in Electrical Engineering from the Aristotle University
of Thessaloniki, Greece, in 1980. Working in the satellite communications and in the error correcting coding area he received
his PhD degree in digital telecommunications from the Aristotle University of Thessaloniki, Greece, in 1994.
In 1980 he joined the Department of Electrical Engineering, Telecommunications Division of the Aristotle University of Thessaloniki
as a research fellow. Since 1997 he is a lecturer of digital communications at the same University. Presently, his research
interests include digital modulations, coding theory, satellite and mobile communications and system simulation.
Stamatis S. Kouris was born in Corfu, Greece. He received the degree of Doctor Engineer in Electrical Engineering from the University of Rome,
Italy and the Diploma of Specialization in Telecommunications of the Instituto Superiore, University of Rome, in 1960 and
1963 respectively. In 1971 he was awarded the PhD Degree of the University of Edinburgh, UK. In the 1974 he was awarded a
specialization Diploma in administration from the University of Pomona CA, USA. He is a member of the Technical Chamber of
Greece, URSI, IRI and other organizations. Since 1964 he has been involved in research on radio-propagation, antennas and
microwaves, working mainly at the Fondazione Bordoni, Italy, University of Edinburgh, UK and University of Thessaloniki, Greece.
He has published several papers on radio-propagation, antennas, communication transmission and microwaves and millimeter-waves
devices. In 1976 he joined with the Department of Electrical Engineering, School of Engineering Science, Aristotle University
of Thessaloniki. He served as professor of telecommunications from 1978 to 2002. Since 2002 he is an emeritus professor. 相似文献
2.
Space diversity reception, in which several signals received at different antennas are combined, is a well known method that can be used to combat the effects of fading in wireless systems. Also, trellis coded modulation (TCM), when combined with interleaving of sufficient depth, is known to provide some form of time diversity that allows the achievement of good error performance in fading environments. In this paper we consider the analysis of the error performance of reference-based Maximal Ratio Combining (MRC) systems when used in conjunction with trellis-coded MPSK modulation techniques over a Rayleigh fading channel. We also consider the analysis of MRC trellis-coded MPSK systems with conventional differential detection. The results are obtained by using a combination of theoretical analysis and simulation. Exact and near-exact expressions for the pairwise error-event probability in Rayleigh fading are derived. Monte-Carlo simulation results, which are more indicative of the exact system performance, are also given. 相似文献
3.
Murat Torlak 《Wireless Personal Communications》2004,28(4):277-286
Many theories of exploiting spatial diversity in wireless communications and more recently space-time coding are results of
understanding the spatial channel models for antenna array communication systems. For example, the models for rich scattering
environments assume the channel coefficients to be almost independent when the spacing between the antennas is sufficient.
This could limit the possibility of extracting direction of the signal propagation with respect to antenna locations (G. Xu
et al., IEEE Transactions on Signal Processing, Vol. 42, No. 2, pp. 349–355, 1994). On the other hand, when the scattering is limited to few dominant reflectors, the directions
of the signals traveling through the environment can prevail in the channel coefficients. Extracting the propagation direction
(beam direction) information from the channel coefficients has been investigated extensively in array signal processing literature.
These investigations have led to many algorithms of direction of arrival (DOA) estimation and beamforming. Here, we propose
a transmit diversity technique that exploits beam directions in environments with few beam directions. While we present this
technique for two-beam Rayleigh fading channels (J.E. Mazo, IEEE Transaction on Communication, Vol. 39, No. 7, pp. 1027–1030, 1991), it can be easily extended to multibeam general fading channels. The proposed method
does not require feedback from the receiver. 相似文献
4.
In this paper, the hybrid selective repeat (SR) automatic repeat request (ARQ) scheme using trellis coded modulation (TCM) proposed by Tellambura and Bhargava [21] is generalized to point-to-multipoint communications for Rayleigh fading channel. Analytical expressions are derived for the throughputs of the point-to-multipoint communication schemes with and without code combining technique. Numerical results show that the protocol using code combining technique yields better throughput than the protocol without code combining and the throughputs decrease when the number of receivers and the value of erasure threshold increase. When the number of receivers equals 1, the scheme without code combining becomes the point-to-point communication scheme proposed in [21]. 相似文献
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Coherent demodulation results in good detection performance but requires channel estimation. Fading pre-compensation (precoding) at the transmitter can lead to low-complex receiver structures with good performance capabilities, without the need for channel estimation. Time division duplex systems based on orthogonal frequency division multiplex (OFDM) are particularly suited to this because intersymbol interference effects can be neglected, simplifying transmitter adjustments. Methods that involve amplitude and/or phase pre-compensation are compared in terms of resulting bit error rate and increase in peak-to-average power ratio. Dynamic channels degrade the performance as the block lengths get longer. For a certain block length the performance degrades below that of traditional differential decoding. A block length of up to 40 times that used in the Digital European Cordless Telephone system, DECT, is possible using channel estimation and ideal Wiener prediction. 相似文献
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Space-time trellis codes have shown to provide a good performance in Rayleigh fading channels. Recently Super-orthogonal space-time trellis codes have shown to outperform these codes, and also provide a systematic design method to maximize diversity and coding gain in quasi-static Rayleigh fading channels. We investigate the performance of these new codes in rapid Rayleigh fading channels and further propose two concatenated versions of these codes. We further investigate the effect of imperfect channel state information on one of the concatenated versions. Some simulation results of the various concatenated schemes in quasi-static and rapid Rayleigh fading channels are presented.
Jayesh N. Pillai received the B.Tech degree in Electrical and Electronic Engineering from the University of Calicut, Kerala, India in 2001. He is currently pursuing an MScEng degree in Electronic Engineering at the School of Electrical, Electronic and Computer Engineering at the University of KwaZulu-Natal, Durban, South Africa. His research interests are in the area of wireless communications, including multiple-antenna systems, space-time coding and channel coding.
Stanley Henry Mneney obtained his B.Sc.(Hons) Eng. Degree from the University of Science and Technology, Kumasi in Ghana in 1976. In 1979 he completed his M.A.Sc. from the University of Toronto in Canada. In a Nuffic funded project by the Netherlands government he embarked on a sandwich Ph.D. programme between the Eindhoven Univesity of Technology and the University of Dar es Salaam, the latter awarding the degree in 1988. His co-supervisors were Prof Jens Arnbak and Prof Ramje Prasad representing the two Universities. The research area was on the application satellite technology to provide low cost systems and services to the rural population in the developing countries.Prof Mneney has taught at the Universities of Dar es Salaam, Nairobi, Durban Westville and he is currently an Associate Professor and Deputy Head of School of Electrical, Electronic and Computer Engineering at the University of KwaZulu-Natal in South Africa. His research interest includes Signal and Image processing, radio propagation and communication systems. 相似文献
10.
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
11.
We introduce a new design method for space-time trelliscodes (STTC's) in orthogonal frequency-division multiplexing(OFDM) systems with frequency-selective fading. First, byanalyzing the pairwise error probability (PEP), we conclude thatlarge effective length and random interleaving are twocritical principles in designing robust space-time codes (STC's)for OFDM systems. Then, based on the analogy between the proposedSTC design principles for multiple-antenna OFDM systems and thetrellis-coded modulation (TCM) code design criteria forsingle-antenna flat-fading channels, we develop a new STTC designmethod. At each trellis stage, this method converts the singleoutput code symbol of a traditional TCM code into several STTCcode symbols, which are to be simultaneously transmitted frommultiple transmitter-antennas, and hence results in a new class ofSTTC's. In this way, the effective lengths that have beenoptimized for traditional TCM codes are preserved in the resultingSTTC's; together with a random interleaver, the proposed new classof STTC's can robustly and efficiently exploit both the spatialand the frequency-selective fading diversity resources inmultiple-antenna OFDM systems. Finally, the excellent performanceof the proposed STTC's are demonstrated through computersimulations. 相似文献
12.
E. Chiavaccini G. M. Vitetta 《International Journal of Wireless Information Networks》2001,8(2):85-98
In this paper optimum one-shot detection over known and partially known doubly-selective Rayleigh fading channels is investigated. Reduced complexity channel models based on Gauss Quadrature Rules (GQRs) and Taylor power series are derived and are employed to develop novel analytical tools for the performance analysis of one-shot detectors. Numerical results allow to assess the implicit diversity gain provided by both channel multipath and signal fading and the energy loss due to the mismatch of the receiver filter. 相似文献
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介绍了瑞利衰落信道下采用扩频信号的失真接收机获取隐分集增益机理.在多重分集通道和每个分集通道存在离散多径的瑞利信道模型基础上,分别详细分析推导了单重分集通道和多重分集通道情况下的隐分集性能表达式,给出了不同情况下的误码性能理论曲线,并在硬件系统测试平台上,对扩频信号的隐分集性能进行了实测.测试结果表明该分析方法可行,可用于指导工程实践. 相似文献
16.
Error Rates in Generalized Shadowed Fading Channels 总被引:5,自引:2,他引:3
Most of the existing models to describe the shadowed fading channels use either the Suzuki or Nakagami-lognormal probability
density function (pdf), both based on lognormal shadowing. However, these two density functions do not lead to closed form
solutions for the received signal power, making the computations of error rates and outages very cumbersome. A generalized
or compound fading model which takes into account both fading and shadowing in wireless systems, is presented here. Starting
with the Nakagami model for fading, shadowing is incorporated using a gamma distribution for the average power in the Nakagami
fading model. This compound pdf developed here based on a gamma-gamma distribution is analytically simpler than the two pdfs
based on lognormal shadowing and is general enough to incorporate most of the fading and shadowing observed in wireless channels.
The performance of coherent BPSK is evaluated using this compound fading model. 相似文献
17.
Mitigation of multipath fading effects and suppression of multiuser interference (MUI) constitute major challenges in the design of the third generation wireless mobile systems. Space-time (ST) coding offers a attractive solution to cope with mutipath fading, but most existing ST coding schemes assume flat fading channels that may not be realistic for wide-band communications. Especially multiuser ST block-coded transmissions through multipath fading channels present unique challenge in suppressing not only MUI but also intersymbol/chip interference. In this paper, we design ST multiuser transceivers for MC-CDMA quasi-synchronous systems, capable to reliably transmit over frequency-selective multipath downlink channels. The proposed system is able to provide transmit diversity and to guarantee symbol recovery in multiuser environments, regardless of unknown multipath. Unlike existing approaches, the mobile does not need to know the channel of other users. In addition to decoding simplicity, computer simulations show the performance merits of the proposed transceiver. 相似文献
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该文提出了两种新的适用于时变信道下空时分组编码多用户系统的解码器设计方案。空时分组编码多用户系统下,传统的迫零(Zero Forcing, ZF)和最小均方误差(Minimum Mean Squared Error, MMSE)解码器设计均假定信道准静态衰落。信道时变时,这些传统解码器在解码某用户信号时引入符号间干扰(Inter-Symbol Interference, ISI),且这种干扰随信道时变增大而增加。基于此,该文设计了两种新的解码器,该解码器可显著降低信道时变的影响。仿真结果表明,随信噪比(Signal-to-Noise Ratio, SNR)增加,两种传统解码器均出现误码率性能平层,而新解码器获得了显著的性能改善。 相似文献