Scalar Additive White Gaussian Noise Research Articles

A Simple Capacity-Achieving Scheme for Channels With Polarization-Dependent Loss

We demonstrate, for a widely used model of channels with polarization dependent loss (PDL), that channel capacity is achieved by a simple interference cancellation scheme in conjunction with a universal precoder. Crucially, the proposed scheme is not only information-theoretically optimal, but it is also exceptionally simple and concrete. It transforms the PDL channel into separate scalar additive white Gaussian noise channels, allowing off-the-shelf coding and modulation schemes designed for such channels to approach capacity. The signal-to-noise ratio (SNR) penalty incurred under 6 dB of PDL is reduced to the information-theoretic minimum of a mere 1 dB as opposed to the 4 dB SNR penalty incurred under naive over-provisioning.

Employment of Generalized Receiver in DS-CDMA with STBC over Fading Channels: Capacity and Error Probability

The capacity and error probability of orthogonal space-time block codes (STBCs) are considered for the pulse-amplitude modulation (PAM), phase shift keying (PSK), quadrature-amplitude modulation (QAM) in fading channels. The suggested approach is based on employment of the generalized approach to signal processing in noise over the equivalent scalar additive white Gaussian noise channel with a channel gain proportional to the Frobenius norm of the matrix channel for the STBC. Using this effective channel, the capacity and probability of error expressions are derived for the PSK, PAM, and QAM modulation with space-time block coding. The Rayleigh, Rician and Nakagami fading channels are considered. As an application, these results are extended to obtain the capacity and probability of error for a multiuser direct sequence code-division multiple-access (CDMA) system constructed on the basis of the generalized approach to signal processing in noise employing the space-time block coding.

Signal Processing by Generalized Receiver Using DS-CDMA with STBC Technology in Multidimensional Systems over Fading Channels: Capacity and Error Probability

The capacity and error probability of orthogonal space-time block codes (STBCs) are considered for the pulse-amplitude modulation (PAM), phase shift keying (PSK), quadrature-amplitude modulation (QAM) in fading channels. The suggested approach is based on employment of the generalized approach to signal processing in noise over the equivalent scalar additive white Gaussian noise channel with a channel gain proportional to the Frobenius norm of the matrix channel for the STBC. Using this effective channel, the capacity and probability of error expressions are derived for the PSK, PAM, and QAM modulation with space-time block coding. The Rayleigh, Rician and Nakagami fading channels are considered. As an application, these results are extended to obtain the capacity and probability of error for a multiuser direct sequence code-division multiple-access (CDMA) system constructed on the basis of the generalized approach to signal processing in noise employing the space-time block coding

An Upper Bound for the Capacity of Amplitude-Constrained Scalar AWGN Channel

This letter slightly improves the upper bound in Thangaraj et al. for the capacity of the amplitude-constrained scalar Additive White Gaussian Noise (AWGN) channel. This improvement makes the upper bound within 0.002 bits of the capacity for $({E_{b}}/{N_{0}})\leq 2.5$ dB.

Capacity Analysis of Adaptive Transmission with Space–Time Block Codes in Spatially Correlated MIMO Nakagami- $$m$$ m Fading Channels

In this paper we investigate the impacts of spatial fading correlation on channel capacity of orthogonal space---time block codes (STBCs) over multiple-input multiple-output Nakagami- $$m$$ m fading under different power and rate allocation policy. This paper presents the single-input single-output equivalency of STBC which is equivalent to scalar additive white Gaussian noise channel, with a channel gain proportional to the Frobenius norm of the matrix channel. We derive the characteristic function (c.f.) of the signal-to-noise ratio at the output of the STBC decoder, when spatial fading correlation is assumed. The c.f. turns out to be a linear combination of Laplace transforms weighted by the eigenvalues of the channel correlation matrix, where each element corresponds to an elementary Gamma probability density function. Based on this approach, and using the linearity of the Laplace transform, the capacity expressions are derived for STBC under different adaptive transmission policy. Numerical results illustrate the impact of fading correlation and fading severity on the channel capacity and outline the performance differences between the distinctive adaptation policies.

High-SNR Asymptotics of Mutual Information for Discrete Constellations With Applications to BICM

Asymptotic expressions of the mutual information between any discrete input and the corresponding output of the scalar additive white Gaussian noise channel are presented in the limit as the signal-to-noise ratio (SNR) tends to infinity. Asymptotic expressions of the symbol-error probability (SEP) and the minimum mean-square error (MMSE) achieved by estimating the channel input given the channel output are also developed. It is shown that for any input distribution, the conditional entropy of the channel input given the output, MMSE and SEP have an asymptotic behavior proportional to the Gaussian Q-function. The argument of the Q-function depends only on the minimum Euclidean distance (MED) of the constellation and the SNR, and the proportionality constants are functions of the MED and the probabilities of the pairs of constellation points at MED. The developed expressions are then generalized to study the high-SNR behavior of the generalized mutual information (GMI) for bit-interleaved coded modulation (BICM). By means of these asymptotic expressions, the long-standing conjecture that Gray codes are the binary labelings that maximize the BICM-GMI at high SNR is proven. It is further shown that for any equally spaced constellation whose size is a power of two, there always exists an anti-Gray code giving the lowest BICM-GMI at high SNR.

基于TAS/STBC方案的深空通信系统的性能分析

为了进一步改善系统性能，本文提出了一种级联编码调制的使用发射天线选择(TAS)和正交空时分组码(STBC)的深空通信系统的方案。在可变参数Rician衰落信道下，基于标量的加性高斯白噪声(AWGN)信道的方法，得到了系统在接收端信噪比的表达式。然后对不同条件下的系统的平均符号误码率(ASEP)性能做了仿真，仿真结果表明：本文所提出的方案，能够显著改善系统的性能，使系统的平均符号误码率大大降低，从而能够缓解发展中的深空通信中将会遇到的功率受限和频带紧张问题。 In order to improve the system performance, a novel deep space communication system scheme employing transmitting antenna selection (TAS) and orthogonal space-time block code (STBC) concatenated with coding modulation is proposed in this paper. Based on the scalar additive white Gaussian noise (AWGN) channel approach, the exact form expressions of the signal-to-noise ratio (SNR) at the receiving end are derived under the variable-parameter Rician fading channels. Then the system performance under different conditions was evaluated through numerical simulations. Numerical results show that: the proposed scheme could distinctly improve the system perfor- mance, with the average symbol error probability decreasing greatly, thus being able to relieve the power limit and bandwidth shortage emerging in the development of deep space communica- tion.

TAS/STBC系统在相关Rayleigh信道下的性能分析

针对相关Rayleigh信道，研究了使用发射天线选择(TAS)和正交空时分组码(OSTBC)的多输入多输出(MIMO)系统的平均符号误码率(ASEP)性能。首先采用了非常适合室内信道的Laplacian模型，得到了两个天线之间的相关系数，它是天线间隔，功率方位角谱(PAS)的标准差和平均到达角(AOA)三者的函数。然后引入了相关矩阵，建立了TAS/STBC系统的相关信道模型，基于等效的标量加性高斯白噪声(AWGN)信道的方法，得到了系统在接收端信噪比的表达式。最后对不同条件下的系统的平均符号误码率(ASEP)性能做了仿真，仿真结果表明：TAS/STBC系统的ASEP性能受到空间相关性的影响，尤其是天线间隔，功率方位角谱(PAS)的标准差和平均到达角(AOA)三者的影响。 The average symbol error probability (ASEP) of multiple-input multiple-output (MIMO) systems employing transmit antenna selection (TAS) and orthogonal space-time block code (OSTBC) over correlated Rayleigh fading channels is considered. We first derive the correlation coefficients between two antenna elements as a function of the antenna spacing, the standard deviation of the power azimuth spectrum (PAS) and the mean angle of arrival (AOA) for the truncated Laplacian model, which is appropriate for indoor channels. Then we introduce the correlation matrix, and establish a correlated channel model. Based on the equivalent scalar additive white Gaussian noise (AWGN) channel approach, the exact form expressions of the signal-to-noise ratio (SNR) at the receiving end are derived. The system performance under different conditions was evaluated through numerical simulations. Numerical results show that: the ASEP performance is affected by the spatial correlation, which varies according to the antenna spacing, PAS standard deviation and mean AOA.

Capacity and error probability analysis of orthogonal space-time block codes over correlated nakagami fading channels

In this letter, system capacity and error probability of orthogonal space-time block coding (STBC) is considered for PAM/PSK/QAM modulation in correlated Nakagami fading channels. The approach is based on an equivalent scalar AWGN (additive white Gaussian noise) channel with a channel gain proportional to the Frobenius norm of the matrix channel for the STBC. Closed form capacity and error probability expressions are derived for Nakagami fading channels. Numerical results are given to illustrate the theory

Capacity and Error Probability for Maximal Ratio Combining Reception over Correlated Nakagami Fading Channels

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.

Capacity and Error Probability Analysis for Orthogonal Space-Time Block Codes over Correlated Rayleigh and Rician Fading Channels

In this paper, the capacity and error probability of orthogonal space-time block codes (STBCs) are presented for PAM/PSK/QAM modulation in correlated flat fading channels. We consider an equivalent scalar AWGN (additive white Gaussian noise) channel with a channel gain proportional to the Frobenius norm of the matrix channel. A unified approach to the error probability analysis for correlated Rayleigh and Rician fading channels is presented. Closed form error probability expressions are derived for Rayleigh fading channels. We also determine the capacity and probability of error for a multiuser direct sequence code division multiple access (DS-CDMA) system employing a STBC over correlated fading channels.

Capacity and error probability analysis for orthogonal space-time block codes over fading channels

The capacity and error probability of orthogonal space-time block codes (STBCs) are considered for pulse-amplitude modulation/phase shift keying/quadrature-amplitude modulation (PAM/PSK/QAM) in fading channels. The approach is based on an equivalent scalar additive white Gaussian noise channel with a channel gain proportional to the Frobenius norm of the matrix channel for the STBC. Using this effective channel, capacity and probability of error expressions are derived for PSK/PAM/QAM modulation with space-time block coding. Rayleigh-, Ricean-, and Nakagami-fading channels are considered. As an application, these results are extended to obtain the capacity and probability of error for a multiuser direct sequence code-division multiple-access system employing space-time block coding.