Selection and MRC diversity for a DS/CDMA mobile radio system through Nakagami fading channel (original) (raw)
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Selection diversity for wireless communications in Nakagami-fading with arbitrary parameters
IEEE Transactions on Vehicular Technology, 2001
By means of analytical and numerical methods, the probability of error and the outage probability of selection diversity RAKE receiver system employing direct sequence/code division multiple access (DS/CDMA) is derived. A noise-limited propagation environment is modeled as a Nakagami-fading channel with arbitrary fading parameters and unequal mean power at the receiver. New analytical expressions are derived for the average probability of error and outage probability. Binary detection schemes are considered including binary phase-shift keying (PSK) and frequency-shift keying (FSK). Both coherent and noncoherent detection is considered as well as identical and arbitrary fading. It is shown that the effect of arbitrary fading on system performance is significant and may not be ignored.
The use of coding and diversity combining for mitigating fading effects in a DS/CDMA system
1998
Spatial diversity is an attractive technology to cope with the fading channel encountered in mobile communications. This paper presents novel closed analytical expressions of the bit-error rate (BER) achievable in a coherent binary phase-shiftkeying (CBPSK) direct-sequence code-division multiple-access (DS/CDMA) system for any power delay profile and for either postdetection selection or maximal ratio combining (MRC). In particular, expressions for the cutoff rate R o and for its related parameter D are also formulated in order to assess the system performance under the consideration of some channel coding schemes. Finally, an exemplary study is carried out in order to illustrate the behavior of a realistic space-diversity code-division multiple-access (CDMA) system according to the analytical expressions that have been derived.
An exact performance analysis of triple-branch threshold-based hybrid selection/maximal-ratio combining (THS/MRC) receivers over correlated Nakagami-m fading channels is presented. Our analysis is valid for integer-order fading parameters and an arbitrary covariance matrix. Following the moment-generating function-based approach, the error rate performance of T-HS/MRC receivers for various modulation formats is analytically obtained. Various performance evaluation results are also presented and compared to equivalent simulation ones
Wireless Personal Communications, 2005
In this paper, the impact of the branch correlation on the performance of multiple-cell DS-CDMA cellular systems over Nakagami-m fading channels with arbitrary branch correlation is investigated. The received multipath-faded signals are assumed to experience identical but non-independent correlated Nakagami-m channels within the reference cell. A new closed-form formula for the joint probability density function (joint pdf) of the diversity combiner with arbitrary correlation coefficients in terms of the generalized Laguerre polynomial and the new expressions of average bit-error rate (BER) for the DS-CDMA system are given in this paper. The results, which were also compared with the performance of the single cell environments, demonstrate that the BER is significantly dependent on the correlation characteristic of diversity branching for both single-cell and multiplecell environments.
2013
Signal fading can drastically affect the performance of terrestrial communication systems. Fading caused by multipath propagation can degrade the bit-error-rate (BER) performance of a digital communication system resulting data loss or dropped calls in a cellular system. The Nakagami-m distribution has gained widespread application in the modeling of physical fading radio channels. The primary justification of the use of Nakagami-m fading model is its good fit to empirical fading data. It is versatile and through its parameter m, we can model signal fading conditions that range from severe to moderate, to light fading or no fading. This research paper discusses the generation of Nakagami – m data and once, the Nakagami-m distribution is generated, we applied BPSK modulation technique with Equal Gain Combining [EGC] Diversity technique and Maximal Ratio Combining [MRC] technique to study its SNR (Signal – to – Noise Ratio) and BER.
SC and SSC diversity reception over correlated Nakagami-m fading channels in the presence of CCI
WSEAS Transactions on Communications
Performance analysis of switched-and-stay combining (SSC) and selection combining (SC) diversity receivers operating over correlated Nakagami-m fading channels in the presence correlated Nakagami-m distributed co-channel interference (CCI) is presented. Novel infinite series expressions are derived for the output signal to interference ratio's (SIR's) probability density function (PDF) and cumulative distribution function (CDF). Capitalizing on them standard performance merasures criterion like outage probabilty (OP) and average bit error probability (ABEP) for modulation schemes such as noncoherent frequency-shift keying (NCFSK) and binary differentially phase-shift keying (BDPSK) are efficiently evaluated. In order to point out the effects of fading severity and the level of correlation on the system performances, numericaly obtained results, are graphically presented and analyzed.
BER analysis of space–time diversity in CDMA systems over frequency-selective fading channels
Iet Communications, 2009
The performance of direct-sequence code division multiple access (DS-CDMA) using space -time spreading system, over frequency-selective fading channels, is investigated. The underlying transmit diversity scheme, previously introduced in the literature, is based on two transmit and one receive antenna. It was shown that when employed in flat fast-fading channels, the received signal quality can be improved by utilising the spatial and temporal diversities at the receiver side. We study the problem of multiuser interference in asynchronous CDMA systems that employ transmit/receive diversity using space -time spreading. To overcome the effects of interference, a decorrelator detector is used at the base station. Considering binary phase-shift keying transmission, we analyse the system performance in terms of its probability of bit error. In particular, we derive the probability of error over frequency-selective Rayleigh fading channels for both fast and slow-fading channels. For the fast-fading channel, both simulations and analytical results show that the full system diversity is achieved. On the other hand, when considering a slowfading channel, we show that the scheme reduces to conventional space -time spreading schemes where the diversity order is half of that of fast-fading.
2012 7th International Conference on Electrical and Computer Engineering, 2012
An analytical approach is developed to derive the expression of the Multiple Access Interference (MAI) and Bit Error Rate (BER) of a MC-DS-CDMA system using multiple receiving antennas with Maximal Ratio Combining (MRC), considering Rayleigh fading channel. The analysis is extended to RAKE receiver with Equal Gain Combining (EGC). The results are presented in terms of BER and improvement of receiver sensitivity due to diversity and multicarrier orthogonal modulation. It is noticed that there are significant improvement due to diversity as well as the number of subcarriers in MC-DS-CDMA system.
Effects of selection diversity on error performance of digital mobile radio systems
IEE Proceedings I Communications, Speech and Vision, 1989
The effect of selection diversity reception on the error performance of the digital mobile radio systems is investigated. The binary frequency shift keying system (FSK) using noncoherent (NC) demodulation, with a limiter/ discriminator receiver is considered. All major error causing factors, fading and Gaussian and impulsive noise, are taken into account. The corresponding general expression for the error probability (BER) is derived. This expression is used to analyse the improvements in the BER performance of the considered system gained by the M-branch selection diversity technique.
Performance of MRC Diversity Receivers over Correlated Nakagami-m Fading Channels
We present exact closed-form expressions for the statistics of the sum of non-identical squared Nakagami-m random variables and it is shown that it can be written as a weighted sum of Erlang distributions. The analysis includes both independent and correlated cases with distinct average powers and integer-order fading parameters. The proposed formulation significantly improves previously published results which are in the form of infinite sums or higher order derivatives. The obtained formulae can be applied on the performance analysis of maximal-ratio combining diversity receivers operating over Nakagami-m fading channels.