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This paper presents a non-binary finite-stat Markov channel (FSMC) that captures both the soft-decision information and the temporal correlation of a discrete fading channel (DFC) with 2ξ quantization levels. The parameters of the FSMC that approximate the DFC with fixe parameters are found using the Baum-Welch algorithm. An iterative decoding scheme, based on the sum-product algorithm, is also discussed...
In a binary input additive white Gaussian noise (BIAWGN) channel, belief propagation (BP) decoding for luby transform (LT) codes requires the knowledge of the signal-to-noise ratio (SNR) at the receiver to achieve its optimal performance. An erroneous estimation of the SNR at the decoder is referred to as “SNR mismatch”. SNR mismatch can significantly degrade the BP decoding performance of LT codes...
In this paper we study the initialization step of decoding algorithms for efficient error-control coding techniques, and its dependence of the channel characteristics over which transmission is performed. LDPC and Polar codes are selected as efficient error-control codes operating over different channels. Channels under study are the classic Additive White Gaussian noise channel, the Rayleigh fading...
Error correction coding based on soft-input decoding can significantly improve the reliability of flash memories. Such soft-input decoding algorithms require reliability information about the state of the memory cell. This work proposes a channel model for soft-input decoding that considers the asymmetric error characteristic of multi-level cell (MLC) and triple-level cell (TLC) memories. Based on...
We investigate secure communication over a channel under two different classes of attacks at the same time: a passive eavesdropper and an active jammer. This scenario is perfectly modeled by the concept of arbitrarily varying wiretap channels (AVWCs). It has been shown that uncorrelated codes are not always capable of overcoming the various jamming attacks. On the other hand, correlated random codes...
A novel hybrid orthogonal frequency division multiplexing (H-OFDM) technique, for 5G candidate waveforms, has been proposed to improve the performance of conventional OFDM systems in this paper. In H-OFDM system instead of conventional cyclic prefixes (CPs) it is used hybrid CP as a guard interval. The hybrid CP consists of zero tail (ZT), unique word (UW) and CP. Computer simulations have been performed...
The rising interest in applications requiring the transmission of small amounts of data has recently lead to the development of accurate performance bounds and of powerful channel codes for the transmission of short-data packets over the AWGN channel. Much less is known about the interaction between error control coding and channel estimation at short blocks when transmitting over channels with states...
We propose a decentralized multi-cell aware opportunistic random access (MA-ORA) protocol that almost achieves the optimal throughput scaling in a K-cell random access network with one access point (AP) and N users in each cell. Under our MA-ORA protocol, users opportunistically transmit with a predefined physical layer data rate in a decentralized manner if the desired signal power to the serving...
Motivated by the error behavior in DNA storage channels, in this work we extend the previously studied sequence reconstruction problem by Levenshtein. The reconstruction problem studies the model in which the information is read through multiple noisy channels, and the decoder, which receives all channel estimations, is required to decode the information. For the combinatorial setup, the assumption...
We consider the problem of transmitting classical information over a time-invariant channel with memory. A popular class of time-invariant channels with memory are finite-state-machine channels, where a classical state evolves over time and governs the relationship between the classical input and the classical output of the channel. For such channels, various techniques have been developed for estimating...
Communication over channels with state is a classical problem extensively studied. Herein, the problem statement is extended to consider a multihop channel where the channel state information in hops, unavailable to neither the source, the destination, nor the relay(s), is to be estimated at the destination, along with reliable information transmission. Each relay in the multihop channel forwards...
Hybrid ARQ (HARQ) and link adaptation (LA) are two powerful techniques to improve the data throughput in wireless communication systems. However, when integrated with LA, conventional HARQ does not provide much gain over LA without significantly increasing the number of retransmissions and initial coding rate. In this paper, we explore the feasibility of achieving high throughput by combining HARQ...
The cellular wireless systems are gaining more attention among other connectivity solutions for supporting machine-type communications (MTC). The efficient support of MTC relies on incorporating new features in the communication networks. Ultra-reliable low-latency communications (URLLC) is one of the considered features that is essential for the support of mission-critical applications, such as industrial...
A cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) system that transmits information over a time-varying fading channel is considered. In channels with large Doppler spreads, the frequency orthogonality assumption of OFDM is not valid. Hence, inter-carrier interference (ICI) is introduced, which leads to higher bit error rates (BERs). We propose a channel equalizer based on the BCJR...
The performance of lattice coding and decoding for the ergodic fading point-to-point channel is studied in the presence of channel estimation errors at the receiver. We show that lattice codes achieve rates within a constant gap to that of Medard's scheme with Gaussian input. Interestingly, the gap does not depend on the channel estimation error variance nor the signal-to-noise ratio (SNR), for a...
Interleave division multiple access (IDMA) is a kind of multiple access technique which employs chip-level user-specific interleavers to separate each user's data from the superimposed signal of all users. Pilot-assisted channel estimation for IDMA and pilot-assisted timing tracking for IDMA have been respectively reported in the literature. In this paper, we propose a joint estimation of timing tracking...
This paper presents initial results for a novel 128-antenna massive Multiple-Input, Multiple- Output (MIMO) testbed developed through Bristol Is Open in collaboration with National Instruments and Lund University. We believe that the results presented here validate the adoption of massive MIMO as a key enabling technology for 5G and pave the way for further pragmatic research by the massive MIMO community...
In this paper, we develop a joint channel estimation and decoding method for faster-than-Nyquist signaling (FTNS) transmitting over (quasi-static) time-varying frequency-selective fading channels based on the variational Bayesian (VB) framework. In contrast to existing methods, ours is capable of performing explicit frequency-domain channel estimation and decoding in a turbo mode without requiring...
This paper presents sparse Bayesian learning (SBL)-based estimation schemes for an approximately sparse wireless multipath channel impulse response (MCIR) in a space-time trellis coded (STTC) multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) system. The proposed schemes consider space-time trellis encoding over consecutive OFDM symbols and employ the multiple...
We assume that the states of an unstable dynamical system are encoded and sent to an estimator through an uncertain channel, which is a channel disturbing its inputs in a nonstochastic manner. The encoder's codeword is also fed into another uncertain channel, at whose output an eavesdropper is listening. The estimator should obtain a uniformly bounded system state estimation error, whereas the eavesdropper's...
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