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A new statistical method for examining correlation of chaos-based systems is applied to the analysis of a chaos-based non-coherent tracking loop in the presence of Rayleigh distributed multipath fading. The motivation behind this approach is the lack of accuracy in the treatment of chaos-based code tracking in the presence of Rayleigh fading. The distributions of the critical points on an S-curve have been derived in the fading case and shown to closely match the simulation results. [ABSTRACT FROM AUTHOR]

A method called offset modulation (OM-OFDM) is proposed to control the peak-to-average power ratio (PAPR) of an OFDM signal. This reported work demonstrates the significant modulation, structural and performance differences between an OM-OFDM and CE-OFDM method. The OM-OFDM method in addition is able to accurately control the PAPR of a transmission for a targeted BER, which is currently not possible with CE-OFDM. By using a power performance decision metric (D), the OM-OFDM method is shown to offer a 34 and 3.44 dB net power performance gain (at a BER of 10-4) when compared to a CE-OFDM and traditional OFDM transmission for frequency selective fading channel conditions, respectively. [ABSTRACT FROM AUTHOR]

A recursive and computationally efficient new formula for bit error rate (BER) in multipath channels with several specular components is derived. Using Jensen's inequality, it is shown that one specular component, Rice fading, provides the lowest possible BER. Using Lagrange multipliers to solve a constrained optimisation problem, it is further shown that, for two specular components, BER is maximum when the two components have equal strengths. BERs for three and four specular paths are studied and compared numerically. The results show the impact of the number of specular paths on BER, as well as the smallest and largest BERs. [ABSTRACT FROM AUTHOR]

Proposed is a novel ergodic capacity formula for decode-and-forward (DF) relaying over a very general fast fading channel model, i.e. the channel gains of the links follow independent but non-necessarily identically distributed Nakagami-m distributions. The proposed formula is validated by Monte Carlo simulations and can be computed efficiently. Since the considered channel model is very general, the proposed formula is appropriate for evaluating the performance of DF relaying in a wide variety of realistic wireless channel environments. [ABSTRACT FROM AUTHOR]

The overall outage probability of a two-way amplify-and-forward relaying system with opportunistic relay selection is investigated over Nakagami-m fading channels, and a tight closed-form approximation is derived. Further, closed-form expressions for the overall diversity and coding gains are obtained. Simulation results are presented to verify the analysis. Using these expressions, one can evaluate the outage performance, diversity and coding gains of a two-way relaying system easily and fast. [ABSTRACT FROM AUTHOR]

Formulas are derived to compute the optimal signal constellation, bit error probabilities, and decision thresholds for M-ASK and QAM with non-equal prior symbol probabilities on Rayleigh fading channels. It is shown that the optimal system can improve average Eb/N0 by 5 dB compared to a conventional system, i.e. a system with source coding, equiprobable symbols, and equal space constellation. [ABSTRACT FROM AUTHOR]

A unified analytical framework is developed using a general two-parameter received signal-to-noise ratio (SNR) model for two-hop amplify-and-forward (AF) relaying with a multi-antenna relay, to determine error performance of binary modulation schemes over independent but non-identically distributed Nakagami-m faded links. The multi-antenna relay employs selection combining (SC) and the destination adopts distributed SC. Exact analytical expression is obtained for the cumulative distribution function of received SNR. A pair of generalised closed form expressions for bit error probability has been obtained for two specific AF relay configurations. [ABSTRACT FROM AUTHOR]

Assuming an opportunistic source selection strategy, a tight closed-form approximation for the outage probability of fixed-gain bidirectional cooperative networks is derived. The presented analysis allows for independent, reciprocal Nakagami-m fading channels with distinct fading parameters among the links. Simulation results are presented to corroborate the tightness of the proposed approximations. [ABSTRACT FROM AUTHOR]

The outage probability (OP) of multiple-input multiple-output (MIMO) amplify-and-forward (AF) relay networks using orthogonal space-time block code is investigated. In particular, a closed-form tight lower bound expression for the OP over independently but not necessarily identically distributed Nakagami-m fading channels is derived. Moreover, an asymptotic approximation for OP which reveals the coding and diversity gains is presented. The analytical expressions are validated by Monte-Carlo simulations. [ABSTRACT FROM AUTHOR]

Proposed is an effective approach to suppress noise interference in wireless communications, the expanded time-frequency (ETF-) OFDM system with joint time-frequency spreading. However, in this system, the orthogonality of the spreading code can be destroyed by multipath fading. Developed is a scheme that employs a zero-forcing equaliser at the receiver and assigns spreading codes at the transmitter for this system. Simulation results show that the ETF-OFDM system with the proposed scheme can take advantage of multipath fading to boost performance. [ABSTRACT FROM AUTHOR]

A new expression for the cumulative distribution function (CDF) of the Hoyt (Nakagami-q) distribution is derived. Its evaluation requires only a single numerical integration and its form is particularly well-suited for numerical computation by a Gauss-Chebyshev quadrature (GCQ). This quadrature is analysed and an upper bound on the absolute error is given. As example results to demonstrate the GCQ method's simplicity and efficiency, the computation of the Hoyt CDF and of the outage probability in Hoyt fading channels are presented. [ABSTRACT FROM AUTHOR]

The bit error probability (BEP) of DQPSK with Gray coding over an AWGN channel can be computed simply, although it is hard to integrate and derive the average BEP for fading channels. Presented are novel approximations of the average BEP of DQPSK with Gray coding over fading channels. Numerical results show that the novel formulations are quite accurate. [ABSTRACT FROM AUTHOR]

The proportional fair scheduling (PFS) algorithm is implemented in current 3G wireless networks for high data rate delay-tolerant services. Though the algorithm has low implementation complexity, the problem of proportional fairness is NP-hard. An analytical expression is obtained to approximate the throughput of PFS in cellular networks over Rayleigh fading channels. Comparisons against simulation results show that the expression is accurate. [ABSTRACT FROM AUTHOR]

The effects are investigated of delayed feedback on the system achievable rate (AR) of a multi-user diversity multiple-input multiple-output (MIMO) system over uncorrelated Rayleigh fading channels in a general framework allowing for arbitrary numbers of transmit/receive antennas and various spatial combining schemes. Exact AR expressions are derived for different MIMO schemes, including the selective combining, maximum ratio combining and space-time block codes. Numerical results are presented to examine the validity of the theory. [ABSTRACT FROM AUTHOR]

The asymptotic performance analysis is presented for selective fixed decode-and-forward (DF) cooperation over independent but not identically distributed Nakagami-m fading channels. A tractable closed-form average bit error probability expression is derived at the high signal-to-noise ratio region. The presented expression is quite simple and general for cooperative systems with an arbitrary number of DF relays and fading environment with arbitrary values of severity parameters m≥0.5. [ABSTRACT FROM AUTHOR]

Selection-and-stay combining (SSTC) is addressed and its outage probability is derived for dual-branch diversity on correlated Nakagami fading channels. In the SSTC scheme, the receiver uses the branch with a larger signal-to-noise ratio (SNR) until its SNR is lower than a preset threshold, and selection combining (SC) is used only at the switching instance. Numerical results from analyses and simulations are also presented. [ABSTRACT FROM AUTHOR]

Evaluation of the bit error rate for general M-ary quadrature amplitude modulation (M-QAM) in Nakagami-m fading channels is presented. The analysis considers real values of the Nakagami fading parameter m, and bit-to-symbol mapping that is not necessarily Gray. Analytical and simulation results are compared to illustrate the accuracy of the analysis, taking as examples non-Gray mapped 16-QAM and 32-cross-QAM constellations. [ABSTRACT FROM AUTHOR]

This Letter focuses on the development of a blind adaptive receiver for space-time block coding (STBC) over multipath fading. The constant modulus (CM) criterion is utilised on the received signals, whereby an orthogonality constraint of the transmitted STBC signals prevents the multiple extractions of the same source. Simulation results demonstrate the performance of the proposed algorithm in a fading channel. [ABSTRACT FROM AUTHOR]

Orthogonal space-time block coding in combination with orthogonal frequency-division multiplexing converts frequency-selective multiple-input-multiple-output (MIMO) channels into a set of equivalent scalar Gaussian channels. For MIMO Nakagami-m fading channels in the presence of spatial correlation, a simple and closed-form approximation for the capacity of the equivalent channels is derived with good accuracy. [ABSTRACT FROM AUTHOR]

Closed-form expressions for the level crossing rate and average fade duration of a κ–μ distributed fading signal envelope are presented. The proposed equations are validated by reduction to known Rice, Rayleigh and Nakagami-m special cases. They are also compared with measured data obtained from field trials analysing human body to body radio channels and shown to provide good agreement. [ABSTRACT FROM AUTHOR]

Closed-form expressions for the average level crossing rate and average fade duration are derived for selection diversity receivers, operating over an arbitrary number of independent but nonidentical Nakagami-lognormal fading input signals. The derived analytical results have been validated by simulation. [ABSTRACT FROM AUTHOR]

The effect of the maximum asynchronous arrival time difference (AATD) of the delayed multipath components on the uplink performance of synchronous DS-C DMA systems is investigated., when communicating in a frequency-selective Rayleigh fading channel. Numerical results demonstrate that the achievable user capacity gain may be as high as 64% at a bit error rate of 102, when the maximum AATD is sufficiently low. [ABSTRACT FROM AUTHOR]

The outage probability of a selection combining diversity scheme in correlated lognormal fading channels is derived [3]. Specifically, the authors approximate the correlation matrix by a Green's matrix, which has a tridiagonal inverse. An iterative integration technique is then used to evaluate the outage probability accurately. The result is sufficiently general to cover an arbitrary number of diversity branches and an arbitrary correlation among the diversity branches. Computer simulation is performed to validate the accuracy of our analysis. [ABSTRACT FROM AUTHOR]

Space-time block coding (STBC) is a powerful transmit diversity scheme for multiple antenna systems. A closed-form expression for the Shannon capacity of MIMO systems is derived using STBC under independent and quasi-static flat Rayleigh fading channels. The Shannon capacity of STBC over such channels is expressed as a finite sum of functions that are easy to evaluate, thereby avoiding the need for numerical integration or Monte Carlo simulation. [ABSTRACT FROM AUTHOR]

Cramér-Rao bound expressions are derived in closed-form for data and non-data-aided SNR estimation of BPSK signals in flat Rayleigh fading channels employing uncorrelated dual MRC diversity. Assuming correlation between the two branches, presented are the bounds most conveniently as plots because of their complexity. Bound expressions are also given for the case of no diversity for comparison. [ABSTRACT FROM AUTHOR]

The potential beneficial impact of channel correlations on the capacity of MIMO systems is investigated. In contrast to most previous work, the present analysis is based on a comprehensive model of the channel correlation structure. It is therefore illustrated that fading cross-correlations may increase the ergodic capacity, sometimes even beyond the supposedly ideal case of independent channels. Starting from considerations on an analytical upper bound of the capacity, the study is then supported by simulation results of the actual ergodic capacity in arbitrary MIMO channels using a simple geometry-based stochastic model. [ABSTRACT FROM AUTHOR]

A novel approach to the performance analysis of switched-and-stay combining diversity receivers over independent Weibull fading channels is presented. Closed-form expressions are extracted for important performance parameters, such as the average output signal-to-noise ratio, the amount of fading, the outage probability, and the switching rate. [ABSTRACT FROM AUTHOR]

Presents novel space-time trellis codes for five and six transmit antennas which best satisfy an optimal design criteria for quasi-static flat Rayleigh fading channels. Construction of codes through a reduced code-search method; Evaluation of the codes' performance in terms of frame error probabilities.

For the reception of multicode direct sequence (DS)-CDMA signals, the MMSE frequency domain equalization is applied instead of RAKE combining. The achievable BER performance in a frequency selective Rayleigh fading channel is evaluated by computer simulation. It is shown by computer simulation that the DS-CDMA with MMSE frequency domain equalization outperforms the DS-CDMA with RAKE combining and shows only slight performance degradation compared to the MC-CDMA with minimum mean square error combining (MMSEC). [ABSTRACT FROM AUTHOR]

The performance of a space-time block coded multicarrier code-division multiple-access (MC-CDMA) system operating in Nakagami-m fading channels is investigated. A new explicit closed form expression for bit error probability is derived. The accuracy of the analytical method is verified by computer simulations. [ABSTRACT FROM AUTHOR]

The Nakagami-m distribution is widely used for the simulation of fading channels in wireless communications. A novel, simple and extremely efficient acceptance-rejection algorithm is introduced for the generation of independent Nakagami-m random variables. The proposed method uses another Nakagami density with a half-integer value of the fading parameter, mp = n/2 ⩽ m, as proposal function, from which samples can be drawn exactly and easily. This novel rejection technique is able to work with arbitrary values of m ⩾ 1, average path energy, Ω, and provides a higher acceptance rate than all currently available methods. [ABSTRACT FROM AUTHOR]

The effective rate of multiple input single output (MISO) channels is investigated. Given a general correlation matrix, the effective rate of arbitrarily correlated Nakagami-m and Rician fading is derived in closed-form and verified by Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

A versatile generalised expression for energy detector performance is derived using the α-µ generalised gamma fading model. The derived expression for probability of detection includes as special cases, Nakagami-m, Weibull gamma and inherently their successors. Furthermore, the new expression accommodates non-integer parameters for the fading model and the detector. [ABSTRACT FROM AUTHOR]

A simple analytical framework is presented for the performance analysis of adaptive coded modulation (ACM) over Rician shadowed fading channels. Obtained results find applicability in the prediction of the average spectral efficiency and the average bit error rate achievable by practical ACM schemes in satellite communications systems. [ABSTRACT FROM AUTHOR]

The constellation rotation and cyclic Q-delay technique has been adopted in the second generation terrestrial digital video broadcasting (DVB-T2) standard. It improves the performance under fading channels, but introduces serious complexity problems in the hardware implementation of the demapper. Presented is a simplified demapper scheme that reduces up to 31% the number of required operations with almost no performance degradation. [ABSTRACT FROM AUTHOR]

The effect of transmit and receive antenna correlation on the capacity of opportunistic eigenbeamforming in Rayleigh fading channels is analysed. Simulation results show that the multi-user diversity of opportunistic eigenbeamforming is significantly associated with the receiver antenna correlation rather than the transmit antenna correlation. [ABSTRACT FROM AUTHOR]

The performance of a dual-hop amplify-and-forward relay system, which experiences mixed Nakagami-m and Rician fading channels, is investigated. Based on the closed-form cumulative probability density function of the equivalent end-to-end signal-to-noise ratio, the exact expressions for outage probability and average symbol error probability are derived. The theoretical observations are verified by the Monte Carlo simulation results. [ABSTRACT FROM AUTHOR]

The maximum-likelihood multiple-symbol differential detector (ML-MSDD) has better bit-error-rate performance than many other detectors for differential modulation. Unfortunately, the computational complexity of ML-MSDD quickly becomes prohibitive as the observation window size grows. While low-complexity MSDD algorithms for the time-invariant Rayleigh fading channel have been considered before, there is a need for low-complexity MSDD algorithms for general time-varying Rayleigh fading channels. A polynomial-time complexity approach called semi-definite relaxation (SDR) is employed to achieve differential detection with near maximum-likelihood (ML) performance. The proposed SDR quasi-maximum-likelihood (QML) multiple-symbol differential detection (SDR-QML-MSDD) is efficient in that its complexity is polynomial in the observation window size, even in the worst case, while it exhibits almost the same performance as ML-MSDD does. [ABSTRACT FROM AUTHOR]

The ergodic capacity of dual-hop wireless communication systems with amplify-and-forward fixed gain relays over composite multipath/shadowing fading channels is investigated. Closed-form bound based on Jensen's inequality for the capacity of a dual-hop transmissions system is derived. Numerical results show that the power allocation between the two hops may have effects on system performance. [ABSTRACT FROM AUTHOR]

A low-complexity detection scheme consisting of a sphere decoder and a parallel interference cancellation (PIC) equaliser is proposed for OFDM systems in doubly-selective fading channels. Theoretical analysis and simulation results show that this detection scheme substantially improves the symbol error rate performance of OFDM systems compared with the traditional PIC equaliser while requiring lower complexity at moderate and high signal-to-noise ratios. [ABSTRACT FROM AUTHOR]

The end-to-end performance of dual-hop transmissions with decode-and-forward relaying over independent non-identically distributed Nakagami-m fading channels is investigated. In the analysis, partial relay selection is employed. This recently proposed selection scheme finds applicability in different wireless systems such as ad hoc and sensor networks. Closed-form expressions for the outage probability and average symbol error rates are provided. Furthermore, the overall system performance is illustrated through representative numerical results. [ABSTRACT FROM AUTHOR]

Proper selection of a signal-to-noise ratio threshold largely determines the tightness of an approximation to the frame error rate of a system over a quasistatic fading channel. It is demonstrated that the expression for the optimal threshold value, which has been established for single-input single-output (SISO) channels, remains unchanged for the general case of multiple-input multiple-output (MIMO) channels. [ABSTRACT FROM AUTHOR]

The performance of distributed space–time codes using amplify-and-forward relaying over independent, non-identical, Nakagami-m fading channels is analysed. The symbol error rate is derived using the moment generating function (MGF). The probability density function and MGF of the total SNR are first derived. Then, the MGF is used to determine the error rate. [ABSTRACT FROM AUTHOR]

A novel infinite-series-based approach for the performance analysis of a dual-branch switched-and-stay combining (SSC) diversity receiver operating over Ricean correlated fading channels in the presence of correlated Nakagami-m distributed co-channel interference (CCI) is presented. The performance analysis is based on outage probability (Pout) and average bit error probability (ABEP) criteria. [ABSTRACT FROM AUTHOR]

Using the unified expression as devised by Wojner, an analytical framework is presented to determine error performance of all binary modulation schemes employing coherent or non-coherent detection and operating over a slow flat Rayleigh fading channel with different diversity combining. A class of generalised expressions for the bit error probability has been obtained following the probability density function or the cumulative distribution function approach. [ABSTRACT FROM AUTHOR]

The dependent multivariate Weibull distribution is modelled for correlated fading channels, where the probability density function of a Weibull fading factor is defined with two parameters (ω, β), and the case of equal β is considered. The joint cumulative distribution function and probability density function of the Weibull distribution are derived, and the outage probability of selection diversity is evaluated. [ABSTRACT FROM AUTHOR]

A novel multi-user detector, based on a genetic algorithm-assisted per-carrier MMSE criterion, is proposed for MC-CDMA systems transmitting over time-varying multipath fading channels. The analysed multi-user detector outperforms state-of-the-art adaptive receivers based on deterministic gradient algorithms, particularly for an increasing number of users. [ABSTRACT FROM AUTHOR]

The throughput performance of single-carrier transmission with frequency-domain equalisation (SCFDE) and of orthogonal frequency division multiplexing (OFDM) in a nonlinear fading channel are compared. Their transmission performance when transmission power control (TPC) is used with adaptive modulation and coding is presented. Computer simulation shows that the throughput performance of SCFDE is superior to that of OFDM around the edge of the service area when both amplifier nonlinearity and adaptive modulation and coding are taken into account. [ABSTRACT FROM AUTHOR]

The exact average bit error ratio (BER) of the rectangular quadrature amplitude modulation (QAM) constellation is studied in the context of asynchronous co-channel interference (CCI) and Nakagami-m fading. A new formula is derived for the characteristic function of the CCI, which requires no knowledge of the CCI distribution. [ABSTRACT FROM AUTHOR]

In wireless communications, fixed-point complex independent component analysis (ICA) algorithms have been applied to perform separation of complex signals. Presented is a novel complex adaptive ICA algorithm which employs individual convergence factors for the real and imaginary components of the weight vector. For wireless receivers operating on quadrature amplitude modulation, the adaptive algorithm performs better than the existing complex fast-ICA algorithm in terms of accuracy. Computer simulations confirm the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]