This paper deals with cyclic redundancy check (CRC) decoding when used in the context of non forward error correction (FEC)-encoded IoT systems: CRC decoding remains challenging when combined to continuous phase modulation (CPM). In this paper, a proposed algorithm relying on the candidate diversity principle through a candidate list generation from soft CPM demodulation output combined with CPM-tailored syndrome decoding is evaluated. Applied with Bahl Cocke Jelinek Raviv (BCJR) algorithm for Gaussian minimum shift keying (GMSK) demodulation, it outperforms all existing complexity-affordable methods and performs close to the best evaluated Parallel-List Viterbi Algorithm with usual CRC validation.

A fingerprinting process is an efficient means of protecting multimedia content and preventing illegal distribution. The goal is to find individuals who were engaged in the production and illicit distribution of a multimedia product. We investigated discrete wavelet transform (DWT) based blind video watermarking strategy tied with probabilistic fingerprinting codes to avoid collusion among higher-resolution videos. We used FFmpeg to run a variety of collusion attacks (e.g., averaging, darkening, and lighten) on high resolution video and compared the most often suggested code generator and decoders in the literature to find at least one colluder within the necessary code length. The Laarhoven codes generator and nearest neighbor search (NNS) decoder outperforms all other suggested generators and decoders in the literature in terms of computational time, colluder detection and resources.

We consider the transmission of a continuous phase modulated (CPM) signal through a Gaussian channel affected by Doppler shifts. We propose a receiver robust to the Doppler shifts derived from a non-coherent detection criterion. We compare its performance to another non-coherent receiver based on a linear approximation of the CPM signal (Laurent decomposition) on which we add a Doppler compensation. Simulation results show that the first algorithm is robust to low-moderate Doppler shifts, while the second is robust to any one. We finally compare these two algorithms to delay-optimized differential detectors which do not require any Doppler shift estimation. We also provide complexity estimations to guide the possible complexity-performance trade-offs.

We present the reliability confidence level as a way to quantify reliability for ultra reliable connections in uncertain environments subject to random block-error rate fluctuations. As ultra reliability is usually linked to the low latency constraint, we analyze the reliability confidence level using the latest results on block-error rate in the finite blocklength regime. The analysis is carried out for OFDM-based systems over Rayleigh slow frequency block-fading channels. The reliability confidence level is bounded using analytic expressions which are then applied to solve two optimization problems. We first find the minimal resources (or codeword length) to guarantee a target reliability with a given confidence. We then investigate an optimal resource sharing strategy within the context of 5G New Radio. The solutions for optimization problems are obtained without resorting to cumbersome Monte-Carlo simulations. Numerical evaluations validate the relevance as well as the tightness of the proposed bounds and approximations.

Centralized/Cloud Radio Access Network (C-RAN) separates Baseband Units (BBUs) away from Remote Radio Heads (RRHs) and centralizes BBUs into a BBU pool. This new architecture can facilitate the cooperation between different cells. We apply zero-forcing (ZF) for joint transmission in a C-RAN downlink system. A number of User Elements (UEs) are assigned to be served into different subframes for serving. This paper proposes two user grouping algorithms denoted Global Greedy User Grouping Algorithm (GGUGA) and User Division Algorithm (UDA) to maximize the average achievable sum rate. GGUGA is a typical greedy algorithm. UDA restricts the random selection of UEs groupings into a certain region which increases the chance to make a good choice. GGUGA achieves a similar performance compared to exhaustive enumeration of all possible UEs groupings. The complexity of UDA is much less than the one of GGUGA when the number of UEs for grouping is large at the expense of a small loss in performance.

Centralized/Cloud Radio Access Network (C-RAN) is a promising future mobile network architecture, which can potentially increase the capacity of mobile network meanwhile reducing operators' cost. In standard C-RAN, frequency shifting is made in Remote Radio Heads (RRHs), which are close to the antennas. Signal processing and upper layers are made in Baseband Unit (BBU) pool for multiple base stations. However, this results in high burden on the optical transport network between RRHs and BBU pool. This paper investigates new functional split architectures between RRH and BBU, to reduce the transmission throughput between RRHs and BBUs. Two new architectures are proposed and modeled for the uplink. We propose to move part of physical layer functions of the BBU to the RRH. For the proposed architectures, the transmission rate between RRHs and BBUs depends on the mobile network load, while that of current architecture is constant. Simulation results illustrate that 30 to 40 percent bandwidth can be saved when all the radio channel capacity is used, and up to 70 percent bandwidth when half of the radio channel capacity is used.

In this paper, we propose a multilevel lattice construction, employing binary Reed-Muller codes, for the Rayleigh block fading channel. The construction is performed on a binary two-dimensional lattice partition chain, and Reed-Muller codes are chosen according to capacity rule. The lattice construction based on number-theoretical concepts is explained, and the system's performance is shown for various codeword lengths.

This paper deals with a reduced-complexity per survivor processing-based CPM demodulation. It relies on a trellis with reduced state number and defined from a rational modulation index possibly different from the transmit modulation index and referred to as virtual receiver modulation index. The virtual receiver modulation index should be chosen so as to achieve a tradeoff between error-rate performance and complexity reduction. The main purpose of this paper is the choice of the virtual receiver modulation index. It gives guidelines to discard the values of the virtual receiver modulation index, that degrade the error-rate performance. Two criteria are used. The first one considers the uncoded CPM case and is based on an approximation of the minimal Euclidean distance. The second one is related to the bit interleaved coded CPM case and resorts to an EXIT chart to analyze the convergence of the iterative receiver.

Machine type communications (MTC) require short- length frames to improve the latency and to achieve high reliability when combined to advanced automatic request (ARQ) mechanisms. The use of short frames has a direct impact on the physical layer, especially on the forward-error correction code (FEC) performance. In this article, lattice based codes are used to achieve an efficient joint decoding of the code and the modulation. The linear group structure of lattices makes it possible to design a decoder based on a sphere decoder. To improve the performance for lower spectral efficiencies, the decoder design takes into account the inevitable lattice shaping processing of the transmitter. With a small number of dimensions, the frame lengths are very short and well suited to MTC. A comparison in frame error rate is performed between the proposed lattice code and an LTE inspired baseline, designed upon the LTE turbo code. Simulation results show that for equivalent spectral efficiencies, a gain in frame length is obtained. This frame length reduction can be employed for increasing the number of users in a machine type communication system.

We consider binary continuous phase modulation (CPM) signals used in some recent low-cost and low-power consumption telecommunications standard. When these signals are generated through a low-cost transmitter, the real modulation index can end up being quite different from the nominal value employed at the receiver and a significant performance degradation is observed unless proper techniques for the estimation and compensation are employed. For this reason, we design new binary schemes with a much higher robustness. They are based on the concatenation of a suitable precoder with binary input and a ternary CPM format. The result is a family of CPM formats whose phase state is constrained to follow a specific evolution. Two of these precoders are considered. We will discuss many aspects related to these schemes, such as the power spectral density, the spectral efficiency, simplified detection, the minimum distance, and the uncoded performance. The adopted precoders do not change the recursive nature of CPM schemes. So these schemes are still suited for serial concatenation, through a pseudo-random interleaver, with an outer channel encoder.

Most source coding standards (voice, audio, image and video) use Variable-Length Codes (VLCs) for compression. However, the VLC decoder is very sensitive to transmission errors in the compressed bit-stream. Previous contributions, using a trellis description of the VLC codewords to perform soft decoding, have been proposed. Significant improvements are achieved by this approach when compared with prefix decoding. Nevertheless, for realistic VLCs, the complexity of the trellis technique becomes intractable. In this paper, we propose a soft-input VLC decoding method using an a priori knowledge of the lengths of the source-symbol sequence and the compressed bit-stream with Maximum A Posteriori (MAP) sequence estimation. Performance in the case of transmission over an Additive White Gaussian Noise (AWGN) channel is evaluated. Simulation results show that the proposed decoding algorithm leads to significant performance gain in comparison with the prefix VLC decoding besides exhibiting very low complexity. A new VLC decoding method generating additional information regarding the reliability of the bits of the compressed bit-stream is also proposed. We consider the serial concatenation of a VLC with two types of channel code and perform iterative decoding. Results show that, when concatenated with a recursive systematic convolutional code (RSCC), iterative decoding provides remarkable error correction performance. In fact, a gain of about 2.3 dB is achieved, in the case of transmission over an AWGN channel, with respect to tandem decoding. Second, we consider a concatenation with a low-density parity-check (LDPC) code and it is shown that iterative joint source/channel decoding outperforms tandem decoding and an additional coding gain of 0.25 dB is achieved.

Selected mapping (SLM) is considered as a practical probabilistic PAPR reduction method for OFDM systems. A problem of this technique is its high computational complexity due to multiple inverse Fourier transform. We suggest a decimation in frequency IFFT scheme together with an interleaver butterfly ensemble to generate multiple candidates. Orthogonality in the frequency domain is kept and better PAPR reduction performance is achieved without additional complex multiplication. Moreover, we obtain a better error rate over both the AWGN channel and the frequency selective fading channel.

In this paper we propose the Arranged List of the Most a priori Likely Tests (ALMLT) algorithm, which is an efficient algorithm for reliability-based soft-decision decoding of long linear block codes. Based on order statistics, we define the mean bit reliabilities and use them to estimate the a priori weight of an error pattern. Each error pattern is represented by a test vector. All the test vectors are sorted according to the increasing order of their weights and saved in a list. Since these weights only depend on the channel SNR, the generation of the list is performed off the transmission. The list of test vectors is then used to decode the received binary sequence similarly as in the Ordered Statistic Decoding (OSD) algorithm. The ALMLT algorithm outperforms the OSD(2) algorithm as illustrated by decoding the binary image of the (255, 239,17) RS code and has a lower mean number of tests, while using the same stopping criterion.

Through a rapid survey of the architecture of low-density parity-check (LDPC) decoders, this paper proposes a general framework to describe and compare the LDPC decoder architectures. A set of parameters makes it possible to classify the scheduling of iterative decoders, memory organization, and type of check-node processors and variable-node processors. Using the proposed framework, an efficient generic architecture for nonflooding schedules is also given.

The purpose of this paper is to calculate the bit error rate (BER) of a multiband non-coherent on-off keying (OOK) demodulation. The results fit perfectly the simulations of the system. It allows us to study the influence of the filter and the decimation factor on the modulation performance. It is also possible to optimize the system by means of other criteria (e.g. system complexity, jammer sensitivity), thus avoiding time consuming simulations.