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We discuss the threat that hardware Trojans (HTs) impose on wireless networks, along with possible remedies for mitigating the risk. We first present an HT attack on an 802.11a/g transmitter (TX), which exploits Forward Error Correction (FEC) encoding. While FEC seeks to protect the transmitted signal against channel noise, it often offers more protection than needed by the actual channel. This margin...
Two-dimensional magnetic recording (TDMR) which combines shingled magnetic recording (SMR) [1] with two-dimensional signal processing attracts attention in hard disk drives (HDDs).
In magnetic recording system, each track or sector may suffer different distortion and noise levels, for example, media noise, intersymbol interference (ISI)/inter-track interference (ITI), reader sensitivity (in case of multi-reader), resulting in unequal error rates or unequal ISI channels.
Cross-entropy (CE) based stopping criteria is known for its early termination capability of the turbo decoding iterations without scarifying its performance, in terms of bit error rate (BER). This advantage, however, performs well in high signal-to-noise ratio (SNR) albeit requiring infinite iterations at low SNR, thereby resulting in more unwanted computations and decoding delays. In this paper,...
The paper explores the background and development of Turbo code, and analyzes the basic principle of coding and decoding in Turbo code. Based on CCSDS standard, the implementation and simulation of Turbo coding and decoding is presented. The article analyzes some factors which may influence BER performance such as iteration times, code rate, and decoding algorithm.
Polar codes are applied to bit-interleaved coded modulation system with iterative decoding (BIPCM-ID) system. To optimize the iterative decoding performance, conventional polar coding construction is modified by extrinsic information transfer (EXIT) chart methodology. Simulation results show that BIPCM-ID system based on the proposed technique can outperforms BIPCM over 16-ary quadrature-amplitude...
The decoding performance of polar codes strongly depends on the decoding algorithm used, while also the decoder throughput and its latency mainly depend on the decoding algorithm. In this work, we implement the powerful successive cancellation list (SCL) decoder on a GPU and identify the bottlenecks of this algorithm with respect to parallel computing and its difficulties. The inherent serial decoding...
This paper investigates the problem of recovering an n-dimensional BPSK signal x0 ∈ {−1, 1}n from m-dimensional measurement vector y = Ax+z, where A and z are assumed to be Gaussian with iid entries. We consider two variants of decoders based on the regularized least squares followed by hard-thresholding: the case where the convex relaxation is from {−1, 1}n to ℝn and the box constrained case where...
Offset-QAM-based filterbank multicarrier (FBMC-OQAM) modulations are known to progressively loose their orthogonality as the channel gets more selective in time and frequency. The effect of channel frequency selectivity on FBMC-OQAM systems has been extensively studied in the literature. Many compensations methods have been proposed to combat it. However, most of them have a significant implementation...
We study the transmission of confidential messages across a wireless broadcast channel with K > 2 receivers and K helpers. The goal is to transmit all messages reliably to their intended receivers while keeping them confidential from the unintended receivers. We design a codebook based on nested lattice structure, cooperative jamming, lattice alignment, and i.i.d. coding. Moreover, we exploit the...
In this paper, we propose a new setup for a cooperative multi-relay non-orthogonal multiple access scheme (CMR-NOMA) to enhance the downlink performance of non-orthogonal multiple access, while operating in severe fading. We compare the performance of the proposed scheme to an existing cooperative non-orthogonal multiple access scheme (CNOMA) in terms of the user-average bit error rate, the ergodic...
Gradient descent bit-flipping (GDBF) algorithm achieves good error performance for decoding low density parity check codes. In the GDBF algorithm, a search point is apt to be trapped in a local optimum, which causes performance degradation of the GDBF algorithm. To overcome this issue, the noisy GDBF algorithm introduces random perturbation into the inversion function of each symbol, which decreases...
In this paper, a low complexity MIMO detection is proposed for MIMO-Constant Envelope Modulation (MIMO-CEM) transceiver system. In which, an adaptive sphere decoder (SD) based on an affine linear transformation model is proposed to adaptively select a small number of candidate sequences from all lattice states. Then, the more accurate (the more complex) IF based maximum likelihood MIMO-CEM decoder...
the complexity of sphere detection algorithm is high when the Signal to Noise Ratio (SNR) is low. For this problem, a new type of detection algorithm of sphere decoder is proposed. The new algorithm reduces the radius of sphere when the SNR is low by using the Minimum Mean Square Error (MMSE) algorithm and a compressibility factor. With the result of simulation, It shows that when the SNR is less...
The article describes the authors' experience in results processing of quality characteristics measurements of signal of Digital Radio Mondiale standard (robustness mode E) during field trials in the experimental broadcasting area, organized in Saint-Petersburg.
Most of the turbo decoding stopping criteria assume perfect channel reliability available at the receiver since they require a threshold based on signal-to-noise ratio (SNR) information. However, operational environments can vary according to frame sizes, code structures and channel reliability requirements, further aggravating the difficulty in threshold determination and convergence or non-convergence...
Abstract-We consider the problem of designing constellation sets for multistage systems for high spectral efficiencies. In particular we will focus on two-stage systems where the cascaded decoding stages are associated to three types of receivers with different complexities and performances. The optimal receiver (S) processes the symbol LLR and delivers the maximum possible throughput, the simpler...
Due to their lack of assessment mechanisms of link quality in VANET environments, routing protocols do not deal efficiently with highly volatile links. One way to fill this gap would be to anticipate links breakages with new route computation. Currently available link quality indicators are not sufficiently responsive to consider forecasting. In this paper we present a novel predictive link quality...
Many aspects of lattice coding and decoding under time-varying multiple-antenna systems remain unexplored. This paper studies the achievable rates using lattice codes for the multiple-input- multiple-output (MIMO) point-to-point channel with ergodic fading and channel state information at the receiver. The proposed lattice coding scheme involves the use of decision regions that are universal for almost...
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