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The asymptotic probability distribution of the mutual information of a separately correlated Rician fading multiple-input multiple-output (MIMO) channel is addressed. The mean and variance of the mutual information are derived when the number of transmit and receive antennas grows asymptotically large while their ratio approaches a finite constant. This derivation is based on the replica method, widely used in theoretical physics and, more recently, in the analysis of communication systems (code-division multiple access (CDMA) and MIMO). Though the replica method allows to analyze complex systems in a comparatively simple way, some authors pointed out that its assumptions are not always rigorous. It is shown that the mutual information converges asymptotically to a Gaussian distribution under mild technical conditions, which are tantamount to assuming that the spatial correlation structure has no asymptotically dominant eigenmodes. The accuracy of the asymptotic approach is assessed by numerical results. It is shown that the approximation is very accurate in a wide range of system settings, even when the number of transmit and receive antennas is as small as a few units. Index Terms--Multiple-input multiple-output (MIMO) systems, random matrices, replica method, Rician fading channels.

We consider a multiuser multiple-input multiple-output (MIMO) communication system using code-division multiple access (CDMA) and multiuser detection to discriminate the different users. Our focus is on the CDMA uplink of a frequency-nonselective Rayleigh fading channel. We study two types of receivers: joint receivers, which address simultaneously both spatial and multiple-access interference; and separate receivers, addressing the two types of interference individually. This approach allows assessing the benefits of adding M1MO processing capabilities to existing multiuser single-input single-output systems. For both receiver types, we analyze solutions based on linear (matched filter, decorrelator, minimum mean-square error) and maximum-likelihood receivers. For all the receivers considered, we provide closed-form expressions (as expectations of given functions) of the resulting pairwise error probabilities. Performance results are obtained in terms of frame-error rate versus [E.sub.b]/ [N.sub.o], following two different approaches. An analytic approach using large-system asymptotic methods, whereby the system parameters (number of users and antennas, spreading gain) are assumed to grow to infinity with finite limiting ratios. A computer-simulation approach is used to illustrate the differences between asymptotic and simulation results. Index Terms--Code-division multiple-access (CDMA) systems, multiuser detection, multiuser linear receivers, multiuser multiple-input multiple-output (MIMO) systems.

Multiple-input multiple-output (MIMO) flat-fading channels with channel state information available at the receiver and channel state distribution available at the transmitter are considered. The ergodic capacity-achieving covariance matrix (ECACM) under an average input power constraint is shown to be not unique in general, and three sufficient conditions for the uniqueness are derived. Then, the structure of ECACM is characterized for certain classes of MIMO channels including the following classes of MIMO channels: 1) right-permutationally invariant channels including independent and identically distributed (i.i.d.) channels; 2) right-symmetrically distributed channels; and 3) right-permutationally invariant and right-symmetrically distributed channels. Finally, part of the single-user results are extended to the multiple-access channel. Index Terms--Covariance matrix, ergodic capacity, fading, multiple-input-multiple-output (MIMO) channels, multiple-access multiple--input-multiple-output (MIMO) channels.

We examine the performance of a reduced-complexity doubly iterative decoder for space-time turbo codes on a quasi-static fading channel. The decoder works by using preliminary soft values of the coded symbols, obtained after a limited number of turbo iterations, to reduce the spatial interference from the received signal. Then, new turbo iterations are performed to improve on the quality of the soft values, and so on. Using a number of approximations, we obtain a receiver interface that achieves a good tradeoff between performance and complexity, and allows the use of turbo space-time codes for a large number of transmit and receive antennas. Index Terms--Fading channels, multiple antennas, space-time codes, turbo codes.

The performance of linear MMSE and non-linear (BLAST) interfaces used to decode space-time codes with a limited number of transmit and receive antennas is investigated and reported.

The behavior of 'vertical' BLAST (Bell Labs space-time architecture) is examined in a coded system. How to introduce a simple coding/decoding scheme into a BLAST architecture is described.

We study the asymptotic behavior of space--time codes when the number of transmit and receive antennas grows to infinity. Specifically, we determine the behavior of pairwise error probabilities with maximum-likelihood (ML) decoding and with three types of receiver interfaces: the ML interface, the linear zero-forcing (ZF) interface, and the linear minimum-mean-square-error (MMSE) interface. Two situations are studied: when the number of receiving antennas grows to infinity while the number of transmitting antennas is finite, and when both numbers grow to infinity but their ratio remains constant. We show that with ML or linear interfaces the asymptotic performance of space-time codes is determined by the Euclidean distances between codewords. Moreover, with the two linear interfaces examined here the number r of receive antennas must be much larger than the number t of transmit antennas to avoid a sizeable loss of performance; on the other hand, when r >> t, the performance of these linear interfaces comes close to that of ML. The dependence of error probabilities on Euclidean distance is valid for intermediate signal-to-noise ratios (SNRs) even when the number of antennas is small. Simulations validate our theoretical findings, and show how asymptotic results may be substantially valid even in a nonasymptotic regime: thus, even for few antennas, off-the-shelf codes may outperform space-time codes designed ad hoc. Index Terms--Coding, fading channels, multiple antennas, space-time codes.

We describe a simple technique for the numerical calculation, within any desired degree of accuracy, of the pairwise error probability (PEP) of space-time codes. This method applies also to the calculation of E[Q([square root of [xi]])] for any nonnegative random variable [xi] whose moment-generating function [[PHI].sub.[xi]](s) = E[exp(-s[xi])] is known. Index Terms--Multiple antennas, pairwise error probability (PEP), space-time codes.

We study the synergy between coded modulation and antenna-diversity reception on channels affected by slow Rician fading. Specifically, we assess the impact of channel-state information (CSI) on error probability. We show that with a good coding and constant envelope modulations (for example, phase-shift keying) scheme the loss in performance when CSI is not available is moderate (around 1.5 dB). Moreover, as the diversity order grows, the channel tends to become Gaussian.

Summary: Despite the fast growth of machine‐type communications via satellite, the vulnerability of such networks to intentional interference and malicious jamming attacks is a raising concern. Specifically, in this paper, we address a class of jamming attacks in which the adversary uses the underlying knowledge of the satellite physical and access protocol to increase the jamming impact. In particular, we focused on a type of camouflage jamming attack (using publicly known preamble) to deceive the receiver, which rapidly leads to poor performance. Compared to conventional constant jamming attacks, these jamming strategies are known to be more effective and potentially more harmful to the targeted communication network. We analyze methods to detect such jamming attacks and provide examples of jamming detection techniques for the satellite Internet of Things (IoT) networks. Results indicate the effective performance of the jamming detection techniques for a variety of representative system parameters. More specifically, we introduce a simple (counting) jamming detection method along with numerical results for realistic system parameters, which confirms system design vulnerability as well as how the jammer may improve her strategy. [ABSTRACT FROM AUTHOR]

Following the approach introduced by Cavers and Ho, the performance of component-interleaved multidimensional constellations over the Rayleigh fading channel is evaluated analytically. Error probabilities are approximated by the union bound using an exact expression of the pairwise error probability. Simulation results show that this bound can be used effectively as a design criterion for the selection of high-diversity multidimensional constellation over the Rayleigh fading channel. Index Terms - Component-interleaving, modulation diversity, Rayleigh fading channel, union bound.

It has been recently recognized by Zehavi that the performance of coded modulation over a Rayleigh fading channel can be improved by bit-wise interleaving at the encoder output, and by using an appropriate soft-decision metric as an input to a Viterbi decoder. The goal of this paper is to present in a comprehensive fashion the theory underlying bit-interleaved coded modulation, to provide tools for evaluating its performance, and to give guidelines for its design. Index Terms - Bit-interleaving, channel capacity, coded modulation, cutoff rate, fading channel.

We compare three receivers for coded narrowband transmission affected by fading and co-channel interference. The baseline receiver is based on conventional diversity reception with maximal-ratio combining. A multiuser approach allows us to derive a maximum-likelihood multiuser receiver and its reduced-complexity suboptimal version. Finally, a decorrelating diversity receiver, which seeks a tradeoff between performance and complexity, is studied. Closed-form performance parameters are derived for all the proposed receivers in the case of coded coherent PSK and independent frequency nonselective Rayleigh fading. Index Terms - Cellular systems, coded modulation, fading channels, multiuser communications.

In previous work, we have studied the impact of diversity on coded digital communication systems operating over fading channels. In particular, we have shown that diversity may be thought of as a way of making the channel more similar to a Gaussian one. The present paper extends this analysis to fading channels affected by co-channel interference (CCI). Three receiver models are examined, namely, with coherent detection and perfect channel-state information (CSI), with differential, and with pilot-tone detection. We study the effect of diversity on the irreducible error floor caused by CCI and fading, and the asymptotic behavior of the channel as the diversity order increases. Our results show that, when perfect CSI is available, diversity is able to turn asymptotically the channel into a CCI-free additive white Gaussian noise (AWGN) channel with the same signal-to-noise ratio (SNR). On the other hand, differential and pilot-tone detection do not remove interference in the limit. Nevertheless, also with these detection schemes, diversity achieves significant gains when the SNR is large enough. Calculation of the channel cutoff rate provides guidelines for the design of coded systems with CCI in fading environments. A wide range of examples, validated by computer simulation, illustrates our conclusions. Index Terms - Co-channel interference, coded modulation, diversity reception, fading channels.

We study coded modulation with block differential detection in an arbitrarily correlated Rician fading channel with space diversity. Coded differential q-PSK is included in our analysis as a special case. A metric is chosen that is optimum for perfect interleaving, slow fading, and independent diversity branches. For slow fading, we compare the cutoff rates of the channels resulting from different choices of block length N and diversity index M. Specifically, we show that block detection with diversity may or may not generate a better coding channel than usual differential detection, according to the code selected and the combination of values of M and N. In particular, for low-diversity orders (M = 1.2) and for low-to-medium code rates, differential detection is still an optimal or near-optimal solution, while for high-diversity orders (M [greater than or equal to] 2) and medium-to-high code rates (up to uncoded modulation) block detection with N > 2 can provide a significant gain. An error floor always exists when fading is fast. It decreases exponentially with the product of code diversity and space diversity, so that the latter emerges as a very effective technique for lowering the error floor of a system affected by fast fading. Performance examples based on actual coding schemes are also shown.

We address the problem of designing and analyzing the performance of a coded modulation scheme for the fading channel when space diversity is used. Under fairly general conditions, a channel affected by fading can be turned into an additive white Gaussian noise (AWGN) channel by increasing the number of diversity branches. Consequently, it can be expected (and is indeed verified by our analyses and simulations) that a coded modulation scheme designed to be optimal for the AWGN channel also will perform asymptotically well on a fading channel with diversity. This paper presents bounds on the bit-error probability of a system with coded modulation and diversity for space- and time-correlated Rician flat fading. Specifically, we derive a new method which allows evaluation of the pairwise error probability extremely easily, as well as accurately and computationally fast. The accuracy achieved improves considerably on the widely used, but rather loose Chernoff bound. Starting from this analysis, we study the asymptotic behavior of the fading channel with diversity as the number of diversity branches increases, and we address the effects of diversity on coded modulation performance and design criteria, including the effect on interleaver depth (which affects the total delay of the system). Index Terms - Coded modulation, diversity receivers, fading channels.