Source Bits Research Articles

ABRF: Adaptive BitRate-FEC Joint Control for Real-Time Video Streaming

Adaptive Forward Error Correction (AFEC) algorithms are proposed to achieve efficient Forward Error Correction (FEC) in Real-Time Communication (RTC). However, current AFEC approaches suffer two key limitations. (1) They do not consider the squeezing effect of redundancy on source bitrate while the squeezing usually happens in real RTC applications with limited bandwidth. (2) They estimate the future packet loss simply, ignoring some critical features of packet loss like randomness and multi-pattern. These drawbacks stop them from providing better Quality of Experience (QoE) in RTC services. We propose ABRF, a general QoE-oriented Adaptive BitRate-FEC joint control algorithm. ABRF makes predictions on the network loss pattern in the coming time and jointly calculates the optimal bitrate-FEC decision based on a QoE model for real-time video streaming. Moreover, ABRF is equipped with a fast adaptation method which helps it generalize across diverse network environments. In terms of Video Multi-method Assessment Fusion (VMAF), experimental results tell that ABRF decreases VMAF degradation caused by packet loss by 68%-95% compared with other AFEC algorithms in real-time video streaming in real-world Internet.

12-nm Stable Pre-Amplifier Physical Unclonable Function With Self-Destruct Capability

Physical unclonable functions (PUFs) produce full security keys without needing to store the key directly in nonvolatile memory (NVM) or publicly. PUFs rely on a stable entropy source across voltage, temperature, and lifetime. A high-gain preamplifier (Pre-Amp) bit cell was built into a dense 2-D array configured as 16 cells per bitline (BL) and 64 cells per wordline (WL). A hardware (HW) sample of 40 chips (1 Kb/chip) was manufactured in GLOBAL FOUNDRIES (GF) 12-nm (12 lp) CMOS technology for a total raw bit count of 40 960 bits. HW characterization was performed to support power supply ranging from 0.7 to 1.0 V and junction temperatures ranging from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 40 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C to 125 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> C with a worst case bit error rate (BER) of 0.174% after stabilization. The entropy source array is complete for productization with control logic and analog power system block for process, voltage, and temperature (PVT) compensation. A stable bit identification and sensing circuit is designed to identify bit cells that are robust against varied test conditions. The NIST 800-90B test suite was run on the native array and stable entropy source bits with minimum entropy scores of 0.65/bit and 0.697/bit, respectively. This article then introduces for the first time ever the ability for a PUF key to be corrupted and physically destroyed, which can be utilized to stop a tamper event or to corrupt obsolete chips. In the self-destruct (SD) mode, the entropy source data can be irreversibly destroyed, blocking all future authentication attempts. HW data show the before and after SD bitmaps, where electromigration (EM) physically breaks the connection of the entropy source bit cells from the sensing circuits. A safety lock circuit is also included to prevent inadvertent SD.

Two Applications of Coset Cardinality Spectrum of Distributed Arithmetic Coding

Distributed Arithmetic Coding (DAC) is a practical realization of Slepian-Wolf coding that partitions source space into cosets. Coset Cardinality Spectrum (CCS) is an important property of DAC that was defined in our previous work. In this paper, we give two applications of CCS. First, we find that DAC bitstream is not compact. The rate loss of DAC bitstream is caused by two factors: <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">unequal coset partitioning</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bit indivisibility</i> . It is proved that as code length goes to infinity, the expected value of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bit-indivisibility</i> rate loss will tend to 0.5 for any irrational Rate Change Step (RCS), where the RCS refers to the rate change when one source bit is flipped. With the help of CCS, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bit-indivisibility</i> rate loss can be compensated to some extend. Especially, for any irrational RCS, as code length goes to infinity, the expected value of the remaining <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bit-indivisibility</i> rate loss after compensation will tend to about 0.47. The second application of CCS is DAC decoder design. We derive the formula of path metric and find that in the original paper on DAC, the intuitive formula of path metric is not correct. The <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">backward-replacing</i> algorithm is proposed to make full use of memory. Experimental results confirm the correctness of theoretical analyses.

Efficient Encoding of Constrained Block Codes

We present coding methods for generating $\ell$ -symbol constrained codewords taken from a set, $\mathcal{\mathcal { S }}$ , of allowed codewords. In standard practice, the size of the set $\mathcal{S}$ , denoted by $M=|\mathcal{S}|$ , is truncated to an integer power of two, which may lead to a serious waste of capacity. We present an efficient and low-complexity coding method for avoiding the truncation loss, where the encoding is accomplished in two steps: first, a series of binary input (user) data is translated into a series of $M$ -ary symbols in the alphabet $\mathbb{M}=\{0, \ldots, M-1\}$ . Then, in the second step, the $M$ -ary symbols are translated into a series of admissible $\ell$ -symbol words in $\mathcal{S}$ by using a small look-up table. The presented construction of Pearson codes and fixed-weight codes offers a rate close to capacity. For example, a 255B320B balanced code, where 255 source bits are translated into 32 10-bit balanced codewords, has a rate 0.1% below capacity.

Identifying Radiation-Induced Micro-SEFIs in SRAM FPGAs

Field-programmable gate arrays (FPGAs) are susceptible to radiation-induced effects that can affect more than one memory cell. Radiation-induced microsingle event functional interrupts (micro-SEFIs) are one of such events that can upset several bits at a time. These events need to be studied because they can overcome protection from techniques such as triple modular redundancy (TMR) and error correction codes (ECCs). Extracting these events from radiation data helps to understand if specific resources of the FPGA are more vulnerable and the extent of this vulnerability. This article presents a method based on statistics and fault injection to identify micro-SEFIs from beam-test data in the configuration memory and block RAM (BRAM) of SRAM-based FPGAs. The results show the cross section of these events for the configuration RAM (CRAM) and BRAM for three families of Xilinx SRAM FPGAs gathered throughout three neutron tests. This article also contains data from a fault injection campaign to uncover the possible CRAM source bits causing micro-SEFIs in memory look-up tables (LUTs) of Xilinx 7-series and Ultrascale devices.

Performance Analysis of Sphere Packed Aided Differential Space-Time Spreading with Iterative Source-Channel Detection.

The introduction of 5G with excessively high speeds and ever-advancing cellular device capabilities has increased the demand for high data rate wireless multimedia communication. Data compression, transmission robustness and error resilience are introduced to meet the increased demands of high data rates of today. An innovative approach is to come up with a unique setup of source bit codes (SBCs) that ensure the convergence and joint source-channel coding (JSCC) correspondingly results in lower bit error ratio (BER). The soft-bit assisted source and channel codes are optimized jointly for optimum convergence. Source bit codes assisted by iterative detection are used with a rate-1 precoder for performance evaluation of the above mentioned scheme of transmitting sata-partitioned (DP) H.264/AVC frames from source through a narrowband correlated Rayleigh fading channel. A novel approach of using sphere packing (SP) modulation aided differential space time spreading (DSTS) in combination with SBC is designed for the video transmission to cope with channel fading. Furthermore, the effects of SBC with different hamming distances but similar coding rates is explored on objective video quality such as peak signal to noise ratio (PSNR) and also the overall bit error ratio (BER). EXtrinsic Information Transfer Charts (EXIT) are used for analysis of the convergence behavior of SBC and its iterative scheme. Specifically, the experiments exhibit that the proposed scheme of error protection of SBC = 6 outperforms the SBCs having same code rate, but with = 3 by 3 dB with PSNR degradation of 1 dB. Furthermore, simulation results show that a gain of 27 dB is achieved with SBC having code rate 1/3 compared to the benchmark Rate-1 SBC codes.

A Sampling-based Distributed Source Coding Scheme

In many practical distributed source coding (DSC) schemes that apply channel coding and iterative decoding, correlation estimation provides the likelihood information about the source bits to initialize the decoding algorithms. Therefore, the decoding depends strongly on the accuracy of this correlation estimation information. In this study, a sampling-based scheme for DSC is proposed that takes advantage of the source redundancy without requiring prior knowledge of its statistics. At the sender, the source sequence is sampled to obtain the sampled and unsampled sub-sequences. Then, the un-sampled sub-sequence is compressed by an arithmetic coder. Meanwhile the syndromes of the sampled sub-sequence are also calculated. At the receiver, the correlation between the side information and the un-sampled sub-sequence is used to estimate the conditional marginal distribution of the sampled sub-sequence. Then, the estimated information is used to initialize the likelihood information of the decoding algorithms. Finally, the likelihood information is combined with the received syndromes to perform iterative decoding to recover the original sampled sub-sequence. Experiment results show that the proposed scheme achieves better rate-distortion performance compared with the existing DSC schemes.

Probabilistic Shaping for Protograph LDPC-Coded Modulation by Residual Source Redundancy

Probabilistic amplitude shaping (PAS) has proved to be a promising way to achieve the shaping gain for an additive white Gaussian noise channel with a distribution matcher (DM). However, the DM schemes may suffer a rate loss and increase both complexity and latency, when they are not suited for the input bit stream with redundancy. In this paper, a novel PAS strategy is proposed for a joint source and channel coded modulation system, where the residual source redundancy after source coding can be exploited to obtain both shaping and coding gains. It is shown that the residual source redundancy can be controlled by choosing the row weight distribution for source code, thus making the probability distribution of the modulated symbols be optimized under an appropriate interleaver design. To guarantee the error-floor performance, the source code is constrained by predicting the probability distribution of source bits within target finite-length frames. By jointly designing source and channel codes, the residual source redundancy can also be exploited to achieve the coding gain. Compared with the state-of-the-art code pairs, the proposed code pairs have better error-floor performance, and achieve higher coding and shaping gains without suffering from the rate-loss and the latency caused by DM.

On the Self-Decoding of Polar-Coded HARQ

In this letter, we concern the self-decoding capability of polar-coded hybrid automatic repeat request (Polar-HARQ) schemes. The proposed self-decoding method enables the incremental redundancy (IR) based Polar-HARQ to recover all source bits solely using the retransmission codewords. It provides an extra decoding chance when the joint decoding attempt fails. With this, the final decoding success probability increases such that the number of retransmissions can be reduced and the system latency goes down. We derive one necessary condition for the successful self-decoding, which can also guide the optimization of Polar-HARQ. Three mainstream Polar-HARQ schemes are compared from the perspective of self-decoding. Simulation results validate the analysis.

On the Performance of Wireless Video Communication Using Iterative Joint Source Channel Decoding and Transmitter Diversity Gain Technique

In this research work, we have presented an iterative joint source channel decoding- (IJSCD-) based wireless video communication system. The anticipated transmission system is using the sphere packing (SP) modulation assisted differential space-time spreading (DSTS) multiple input-multiple output (MIMO) scheme. SP modulation-aided DSTS transmission mechanism results in achieving high diversity gain by keeping the maximum possible Euclidean distance between the modulated symbols. Furthermore, the proposed DSTS scheme results in a low-complexity MIMO scheme, due to nonemployment of any channel estimation mechanism. Various combinations of source bit coding- (SBC-) aided IJSCD error protection scheme has been used, while considering their identical overall bit rate budget. Artificial redundancy is incorporated in the source-coded stream for the proposed SBC scheme. The motive of adding artificial redundancy is to increase the iterative decoding performance. The performance of diverse SBC schemes is investigated for identical overall code rate. SBC schemes are employed with different combinations of inner recursive systematic convolutional (RSC) codes and outer SBC codes. Furthermore, the convergence behaviour of the employed error protection schemes is investigated using extrinsic information transfer (EXIT) charts. The results of experiments show that our proposed R a t e − 2 / 3 SBC-assisted error protection scheme with high redundancy incorporation and convergence capability gives better performance. The proposed R a t e − 2 / 3 SBC gives about 1.5 dB E b / N 0 gain at the PSNR degradation point of 1 dB as compared to R a t e − 6 / 7 SBC-assisted error protection scheme, while sustaining the overall bit rate budget. Furthermore, it is also concluded that the proposed R a t e − 2 / 3 SBC-assisted scheme results in E b / N 0 gain of 24 dB at the PSNR degradation point of 1 dB with reference to R a t e − 1 SBC benchmarker scheme.

Efficient Multiple Concatenated Codes With Turbo-Like Decoding for UEP Wireless Transmission of Scalable JPEG 2000 Images

Most multimedia source encoders produce scalable bit streams that are vulnerable to noisy channel effects. Unequal error protection (UEP) designs are attractive solutions for such scalable bit streams. In the other hand, the structure of multiple concatenated codes, which consist of the combination of two or more elementary encoders and interleavers, offers a flexible implementation of unequal data protection. To provide an efficient protection for embedded source bit streams, an adaptive concatenated coding/decoding design is proposed in this paper inspired by serially concatenated turbo codes. This scheme involves iterative decoding of concatenated codes for JPEG 2000 image transmission. In the case of time varying channels, the concatenated coding rates are adaptively chosen to maximize the visual quality. The simulation results show that the proposed scheme achieves better image quality improvements at the receiver side compared with a conventional multiple turbo codes-based design, with significant peak-signal-to-noise ratio gains.

Analysis and Code Design for the Binary CEO Problem Under Logarithmic Loss

In this paper, we propose an efficient coding scheme for the binary Chief Executive Officer (CEO) problem under logarithmic loss criterion. Courtade and Weissman obtained the exact rate-distortion bound for a two-link binary CEO problem under this criterion. We find the optimal test-channel model and its parameters for the encoder of each link by using the given bound. Furthermore, an efficient encoding scheme based on compound LDGM-LDPC codes is presented to achieve the theoretical rates. In the proposed encoding scheme, a binary quantizer using LDGM codes and a syndrome-decoding employing LDPC codes are applied. An iterative decoding is also presented as a fusion center to reconstruct the observation bits. The proposed decoder consists of a sum-product algorithm with a side information from other decoder and a soft estimator. The output of the CEO decoder is the probability of source bits conditional to the received sequences of both links. This method outperforms the majority-based estimation of the source bits utilized in the prior studies of the binary CEO problem. Our numerical examples verify a close performance of the proposed coding scheme to the theoretical bound in several cases.

Status and influencing factors of psychological stress in late pregnant women

Objective To investigate the psychological pressure levels of pregnant women in late pregnancy and to analyze the influencing factors. Provide the basis for the intervention measures. Methods Totally 160 pregnant women in late pregnancy who took part in the antenatal examination were recruited and investigated using Pregnancy Pressure Scale (PPS), Pittsburgh Sleep Quality Index (PSQI), and demographic questionnaire. Results Total score of PPS was (53.06±10.24) points. In order to protect the health and safety of the fetus in pregnant women caused by maternal psychological stress score ranked first in three pressure source bit highest score of (16.46±5.16) points. Total score of PSQI was (7.51± 2.89) points. Compared with the different dimensions of sleep quality, the two dimensions of sleep time and falling asleep time were negatively correlated with pregnancy stress, and the rest were positively correlated. Age, pregnancy, parity, plan the actual sleep time, sleep disorders will be planned to as independent variables. In the late pregnant women psychological pressure as the dependent variable, multiple linear stepwise regression analysis, found that there are 3 variables into the regression equation: parity, pregnancy in plan, sleep disorders (P<0.05). Conclusions Pregnant women have greater psychological pressure in late pregnancy, influenced by the conception, planning pregnancy, sleep disorders and other factors. Nursing staff should take care and guidance for the specific situation, so as to reduce the pregnancy pressure of pregnant women in late pregnancy, and better help them successfully pass the gestation period and delivery period. Key words: Late pregnant women; Psychological pressure; Sleep quality; Influencing factors

The Effect of Local Decodability Constraints on Variable-Length Compression

We consider a variable-length source coding problem subject to local decodability constraints. In particular, we investigate the blocklength scaling behavior attainable by encodings of $r$ -sparse binary sequences, under the constraint that any source bit can be correctly decoded upon probing at most $d$ codeword bits. We consider both adaptive and non-adaptive access models, and derive upper and lower bounds that often coincide up to constant factors. Such a characterization for the fixed-blocklength analog of our problem, known as the bit probe complexity of static membership, remains unknown despite considerable attention from researchers over the last few decades. We also show that locally decodable schemes for sparse sequences are able to decode 0s (frequent source symbols) of the source with far fewer probes on average than they can decode 1s (infrequent source symbols), thus rigorizing the notion that infrequent symbols require high probe complexity, even on average. Connections to the fixed-blocklength model and to communication complexity are also briefly discussed.

The Design and Simulation of Neural Network Encoder in Confidential Communication Field

Both all-connection model and part connection model is simulated, which adopt self-organizing map neural network to generate check bits. Consequently, N source bits and K check bits are composed a complete codeword. In the decoding port, multi-layer perceptron network (MLPN) is utilized to implement decoding function. The specific steps are as follows: (1) Constructing the MLPN according to the size of codeword sets and source bits; (2) Training the MLPN with codeword sets generated by neural network decoder until qualified; (3) Accepting and decoding codeword sets via trained MLPN. Actual tests show that: (1) There exist no evident performance differences between all-connection model and part-connection model; (2) The connection of weight sets is similar to Tanner graph in part-connection model, which reduce the computational complex greatly and remain good performance at the same time. In sum, the method of encoding and decoding has certain market prospect in confidential communication field.

Amplifying the Randomness of Weak Sources Correlated With Devices

The problem of device-independent randomness amplification against no-signaling adversaries has so far been studied under the assumption that the weak source of randomness is uncorrelated with the (quantum) devices used in the amplification procedure. In this work, we relax this assumption, and reconsider the original protocol of Colbeck and Renner using a Santha-Vazirani (SV) source. To do so, we introduce an SV-like condition for devices, namely that any string of SV source bits remains weakly random conditioned upon any other bit string from the same SV source and the outputs obtained when this further string is input into the devices. Assuming this condition, we show that a quantum device using a~singlet state to violate the chained Bell inequalities leads to full randomness in the asymptotic scenario of a large number of settings, for a restricted set of SV sources (with $0 \leq \varepsilon < (2^{(1/12)} - 1)/(2(2^{(1/12)} + 1)) \approx 0.0144$). We also study a device-independent protocol that allows for correlations between the sequence of boxes used in the protocol and the SV source bits used to choose the particular box from whose output the randomness is obtained. Assuming the SV-like condition for devices, we show that the honest parties can achieve amplification of the weak source, for the parameter range $0 \leq \varepsilon<0.0132$, against a class of attacks given as a mixture of product box sequences, made of extremal no-signaling boxes, with additional symmetry conditions. Composable security proof against this class of attacks is provided.

Code Division of the Logical Channels for Transmission of Transactions in the Intelligent Mechatronic Systems

As a rule, modern engineering and manufacturing projects are saturated with electronic equipment for automated monitoring and control, as well as cable communication lines and radio frequency channels for transmission of transactions. During functioning of the intelligent mechatronic systems the number of the communication lines of the frequency ranges is restricted due to application of the CDMA principles. A drawback of this method of channelizing is connected with a high level of the interfering signals in case of an increased quantity of the simultaneously functioning subscribers, whereof signals at the receiving side are highlighted with the hardware and software correlators. Taking this into account, a numeric method was proposed for the accelerated data streams of the bits extraction from the frame bits during the code division multiple access to the transmission of the transactions on the basis of the use of the Walsh function and the intelligent mechatronic systems. The scheme of the code division of the bit streams was analyzed due to introduction of the information source bit streams to the mechatronic system of the intelligent multiplexers at the transmitting channel side and the intelligent bit streams separators at the receiving side. A peculiarity of this code division scheme for the logical channels is that it is fully implemented due to the use of the software as a part of the intelligent mechatronic system. Construction of the software models of the intelligent multiplexer and the intelligent separator proved their high efficiency and stability of their functioning. When up to 256 logical channels are formed in one physical channel, a reliable separation of the information bits is ensured, as well as their diversion by the sources with the allowed delays in the transactions' fulfillment. An essential extra time advantage occurs, because all the separator transactions in the real processor of the bit frames processing take place with the help of short commands of the integer arithmetic.

A joint source–channel coding approach to digital image self-recovery

The aim of the digital image self-embedding methods is to restore the content of a tampered image as much as possible. In this article, a joint source–channel coding solution is presented to solve this problem, in which an image compression algorithm is applied to generate a representation of the original image. The preserved information of the original image is used to produce hash bits that help the receiver to find the tampered area. Having the location of tampering known, it can be modeled as an erasure channel. Therefore, a channel coding phase is added to protect the image representation. The limited watermarking bit-budget will be optimally dedicated to the source and channel code bits based on the results derived by solving a dynamic programming optimization problem. It is shown in the experimental results that including this optimization stage results in the superiority of the proposed scheme to the similar state-of-the-art methods who lack such optimization.

Bilayer expurgated LDPC codes with uncoded relaying

Bilayer low-density parity-check (LDPC) codes are an effective coding technique for decode-and-forward relaying, where the relay forwards extra parity bits to help the destination to decode the source bits correctly. In the existing bilayer coding scheme, these parity bits are protected by an error correcting code and assumed reliably available at the receiver. We propose an uncoded relaying scheme, where the extra parity bits are forwarded to the destination without any protection. Through density evolution analysis and simulation results, we show that our proposed scheme achieves better performance in terms of bit erasure probability than the existing relaying scheme. In addition, our proposed scheme results in lower complexity at the relay.

Multi-Set Space-Time Shift-Keying With Reduced Detection Complexity

In this paper, we propose a novel multi-set space-time shift keying (MS-STSK) technique, where the source bits are conveyed over two components, namely, by activating one out of $M_{Q}$ dispersion matrices of STSK and $M$ antenna combination of the $N_{t}$ available antennas, in a similar fashion to spatial modulation but activating multiple antennas rather than a single antenna. This system requires a smaller number of RF chains than antenna elements (AEs) to achieve an improved throughput. We opt for STSK as the main building block of our proposed MS-STSK as a benefit of its design flexibility, where STSK is capable of providing the system with both diversity and multiplexing gains. The proposed MS-STSK system achieves both higher data rates and a lower bit error rate than the conventional STSK scheme, which is attained at the cost of increased number of AEs and a high-speed antenna switch. Furthermore, as the symbol rate of the MS-STSK system increases, its performance compared with the STSK scheme is significantly improved because of the enhanced diversity introduced by the additional AEs. Furthermore, we propose a reduced complexity detector for Quadrature Amplitude Modulation (QAM)/Phase Shift Keying (PSK) constellations, which—despite its reduced complexity—is capable of achieving the same performance as the optimal maximum likelihood detector.