Symbol Error Research Articles

Analysis of Space Period Blocks Codes for Independent Channel Coefficient Using MIMI-CDMA Techniques

The future of communication system is changing towards high capacity and faster data transmission with error less environment. Wireless and effcient Communication Systems follows the Improvement in the Bit error rate (BER) over fading channel with decrease in the system level complexity. Multiple Input multiple output (MIMO) generally improves spectral effciency and link reliability. And CDMA is a simple technique that has many advantages, spread spectrum gives best results in CDMA technique, for the improvement in signal quality, the combination of both techniques rise to give a simple solution. For better Bit error rate (BER) there is permutation spreading technique runs on space time block code (STBC) matrices. Here the crucial part is spreading strategy that follows frequency of data bits and each transmit antenna uses different spreading sequences gives fewer errors in symbols. The assignment of spreading sequence allotment follows some permutation designs that should have required squared Euclidean distance from message to another message for better spatial diversity, orthogonality and code symmetry. Permutation spreading development can be achieved by changing the pattern of space time block code environment. The results indicate that, there is an improvement in Bit Error rate.

Multi-resolution Lossless Image Compression for Progressive Transmission and Multiple Decoding Using an Enhanced Edge Adaptive Hierarchical Interpolation

In a multi-resolution image encoding system, the image is encoded into a single file as a layer of bit streams, and then it is transmitted layer by layer progressively to reduce the transmission time across a low bandwidth connection. This encoding scheme is also suitable for multiple decoders, each with different capabilities ranging from a handheld device to a PC. In our previous work, we proposed an edge adaptive hierarchical interpolation algorithm for multi-resolution image coding system. In this paper, we enhanced its compression efficiency by adding three major components. First, its prediction accuracy is improved using context adaptive error modeling as a feedback. Second, the conditional probability of prediction errors is sharpened by removing the sign redundancy among local prediction errors by applying sign flipping. Third, the conditional probability is sharpened further by reducing the number of distinct error symbols using error remapping function. Experimental results on benchmark data sets reveal that the enhanced algorithm achieves a better compression bit rate than our previous algorithm and other algorithms. It is shown that compression bit rate is much better for images that are rich in directional edges and textures. The enhanced algorithm also shows better rate-distortion performance and visual quality at the intermediate stages of progressive image transmission.

A novel error correction and encryption algorithm combined fountain code and AES

SummarySatellite broadcast communications make demand on reliable and secure data transmissions. Aiming at balancing data disorder and correlation from encryption and errors correction, this paper proposes a novel error correction and encryption algorithm combined fountain code and advanced encrypt standard (FC‐AES), which constructs a 3‐layer cascade framework for cryptosystem to harmonize the coding payloads of services, products, and users. Furtherly, distributed degree would be compensated with round key, which provides with entire security controls. Information degree is designed to limit data overhead and disorder. Sparsely coding control for product degree is developed to prevent decoding error avalanche. We also provide a suitable decryption scheme for FC‐AES. The simulations show the new algorithm enhances the performance of data‐recovery failure probability by 29.56% and average error symbol rate by 13.09%.

Data-Aided Spatial Modulation

Spatial modulation utilizes the diversity of multiple-input multiple-output channel to improve the spectral efficiency. In time-variant wireless channels, its performance degrades due to the inaccuracy of channel estimation (CE). In this paper, a data-aided channel tracking (DACT) method is proposed to improve its CE accuracy in time-variant wireless channels. Specifically, the demodulated data at current time slot are used to update the subsequent channel state information. Two different DACT methods with different pilot insertion patterns are proposed: 1) feedback DACT (FDACT) where when a symbol error is detected, the receiver will inform the transmitter to insert pilots and estimate the channel again; 2) periodical DACT (PDACT) where pilots are inserted periodically. Theoretical analysis of the CE error in time-variant channels is presented, which indicates that the CE accuracy could be significantly improved in comparison to the conventional counterpart. Moreover, the closed-form expressions of bit error rate for FDACT and frame error rate for PDACT are derived. Simulations are conducted to verify the efficiency of the proposed DACT methodologies.

Network Service Method under Cloud Environment of Wireless Sensor Networks in Disaster Situation

The sensor networks are characterized by tiny, inexpensive, and advanced communication technology. However, wireless ad-hoc sensor networks (WASNs) have some issues such as the limited amount of energy, multipath fading, and some other issues when they applied in disaster situations. For reducing power consumption, we show mathematical analysis of energy saving, and enhanced error symbol probability. The simulation results prove our analysis. As for the multipath fading, we also show the mathematical analysis of fading channel characteristics and channel model, as well as how to mitigate the multipath fading by modulation and diversity techniques. From the simulation results, we prove the proposed system with amplify-and-forward (AF) relaying can achieve a 2.5 dB performance gain the BER 10-4 whereas the achievable improvement is almost a 4 dB at the BER 10-5 when using maximal ratio combining.

Symbolic Quick Error Detection for Pre-Silicon and Post-Silicon Validation: Frequently Asked Questions

Reducing the error detection latency is critical for improving the design visibility while searching for design errors. This article uses a FAQ format to discuss the key points of the symbolic QED method that can be applied during both pre-silicon and post-silicon validation.

Error Probability Model for IEEE 802.15.4 Wireless Communication

Wireless transmission compliant to IEEE 802.15.4 standard can be significantly affected by background noise, multipath fading and interference from other radio sources. The influence of such disturbances is most commonly expressed in a form of error probability statistics. Accurate analytical error probability model is hard to acquire, since IEEE 802.15.4 standard uses imperfect spreading sequences. Some prior works in this field tend to idealize these imperfect spreading sequences in order to simplify calculations for error probability parameters. This paper presents an analytical error probability model for IEEE 802.15.4 communication in Rician fading channel, which uses original imperfect spreading sequences without their idealization. Proposed error probability model consists of mutually dependent chip, symbol, bit and packet error probability models. Presented theoretical results are confirmed by independent numerical simulation of IEEE 802.15.4 transmission through Rician fading channel according to the Monte Carlo method.

Analysis of the CFO Successive Interference Cancellation for the OFDMA Uplink

The uplink of orthogonal frequency division multiple access or single-carrier frequency division multiple access suffers multiple access interference when carrier frequency offset (CFO) is not properly estimated and compensated. In particular, multicarrier uplink CFO compensation is highly complex due to the multiuser context. Successive interference cancellation algorithms are effectively employed to compensate for the CFO, where the interference produced by each user is handled sequentially through a series of iterations. The main contribution of this work is the analysis of the CFO compensation performance of efficient successive cancellation algorithms. We study the mean square symbol error, and derive a useful upper-bound of the compensation technique performance at convergence. This result extends the general convergence results for the space-alternating generalized expectation-maximization algorithm in the CFO compensation scenario. Finally, we validate the analysis with numerical simulations.

Comparative analysis of energy parameters and OFDM-signal reliability receiving with different OFDM sub-carriers number

The effectiveness of the optimal gain for OFDM-signals is proved based on the simulation results. It’s possible to achieve an independence of the energy characteristics and information reliability of group signal generated by technology OFDM from the number of OFDM subcarriers. The paper shows how the value of the optimal gain depends on the OFDM subcarriers number. The analytical expression for determining the optimum gain is realized on the basis of an integral equation, which defines the form of the density distribution of the amplitudes of the amplified signal, and reliability requirements for signal processing, and the value is the desired one. Determination results of are the product of statistical modeling. Knowledge of the value gives you the possibility to calculate the corresponding value of the energy parameter for communication channel (signal to noise ratio) that is the basis for the subsequent analytical calculation symbol and bit error values for each value for signal to noise ratio. The proposed optimal analytical condition is realized on the basis of the solution of an integral equation in which the form of the density distribution is given by a parameter of the distribution for given values of and . The value is the desired one. Determination result for is the product of statistical modeling. If the value is known, then we have a possibility to calculate the corresponding channel parameter value , which is the basis for the subsequent analytical calculation error values and bit error for each channel parameter value value. Justified effect of the described method for forming OFDM-signal allows use this technology as a tool for multiple access communication systems such as promising LTE and other similar technologies. In addition, this property characterizes OFDM technology as potentially effective in a multipath channel, since a change in the number of subcarriers without sacrificing energy received beam allows you to control the duration of a single character, depending on the actual conditions of rays delay, reducing the impact on the quality factor of multipath reception. Reliability losses when using OFDM technology with respect to single-frequency transmission can be compensated for by the selection of an appropriate signal-code structure that containing anti-noise code with the required parameters to achieve required reliability. Reference 5, figures 11, table 1.

High-Speed Parallel Decodable Nonbinary Single-Error Correcting (SEC) Codes

This paper presents a novel construction scheme for nonbinary single-error correcting (SEC) codes that yields high-speed parallel decoding. The proposed scheme utilizes two methods, namely, Improved and Reordered; these methods can be also combined. Both of these methods reduce the number of 1's in the parity-check matrix (H-matrix) by reducing the 1's in every row vector. This results in a reduction in the gate depth in the syndrome generator, thus achieving a shorter delay time for parallel decoding. In the proposed Improved method, for a single $b$ -bit byte (i.e., $\mbox{2}^{b}$ -ary symbol) error correcting code, the submatrix of the H-matrix corresponding to every $b$ -bit byte is multiplied with a regular matrix. The so-called improved submatrix is generated using a heuristic (greedy) algorithm. The proposed Reordered method selects the correct $b$ -bit bytes for deletion when shortening is performed. Simulation results show that the proposed scheme accomplishes a faster parallel decoding time than existing schemes. Furthermore, the proposed scheme is applicable to any class of linear SEC codes, whereas existing schemes are applicable only to specific codes. Extensive simulation results are provided to substantiate the viability of the proposed codes for faster parallel decoding (albeit incurring for most cases in modest increases of area and power dissipation due to additional circuitry).

Decision-aided ICI mitigation with time-domain average approximation in CO-OFDM

Abstract We introduce and investigate the feasibility of a novel iterative blind phase noise inter-carrier interference (ICI) mitigation scheme for coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. The ICI mitigation scheme is performed through the combination of frequency-domain symbol decision-aided estimation and the ICI phase noise time-average approximation. An additional initial decision process with suitable threshold is introduced in order to suppress the decision error symbols. Our proposed ICI mitigation scheme is proved to be effective in removing the ICI for a simulated CO-OFDM with 16-QAM modulation format. With the slightly high computational complexity, it outperforms the time-domain average blind ICI (Avg-BL-ICI) algorithm at a relatively wide laser line-width and high OSNR.

Error Performance Analysis of Multiuser CDMA Systems with Space-time Coding in Rician Fading Channel

In this paper, the error performance of multiuser CDMA system with space-time coding is studied in Rician fading channel, and the corresponding bit error rate (BER) and symbol error rate (SER) analysis are presented. Based on the performance analysis, a simple and effective multiuser receiver scheme is developed. The scheme has linear decoding complexity when it compares to the existing scheme. Based on the performance analysis, and using mathematical manipulation, the BER and SER of multiuser space-time coded CDMA system are derived, respectively. As a result, accurate closed-form expressions of BER and SER are respectively obtained. With these expressions, the performance of multiuser CDMA system with space-time coding can be evaluated effectively. Computer simulation shows that the developed receiver scheme has almost the same performance as the existing scheme, and the theoretical BER and SER can match the corresponding simulation results well

Symbolic dynamics-based error analysis on chaos synchronization via noisy channels

In this study, symbolic dynamics is used to research the error of chaos synchronization via noisy channels. The theory of symbolic dynamics reduces chaos to a shift map that acts on a discrete set of symbols, each of which contains information about the system state. Using this transformation, a coder-decoder scheme is proposed. A model for the relationship among word length, region number of a partition, and synchronization error is provided. According to the model, the fundamental trade-off between word length and region number can be optimized to minimize the synchronization error. Numerical simulations provide support for our results.

Low Complexity Turbo-Equalization: A Clustering Approach

We introduce a low complexity approach to iterative equalization and decoding, or “turbo equalization”, which uses clustered models to better match the nonlinear relationship that exists between likelihood information from a channel decoder and the symbol estimates that arise in soft-input channel equalization. The introduced clustered turbo equalizer uses piecewise linear models to capture the nonlinear dependency of the linear minimum mean square error (MMSE) symbol estimate on the symbol likelihoods produced by the channel decoder and maintains a computational complexity that is only linear in the channel memory. By partitioning the space of likelihood information from the decoder based on either hard or soft clustering and using locally-linear adaptive equalizers within each clustered region, the performance gap between the linear MMSE turbo equalizers and low-complexity least mean square (LMS)-based linear turbo equalizers can be narrowed.

Performance Analysis of Relay-Assisted Cooperative Systems in Correlated Fading Channels

In this paper, the effect of fading correlation at the receiving elements of a linear antenna array in a relay-assisted cooperative single-input multiple-output (SIMO) system has been investigated over flat Rayleigh fading channels. Considering a model of local scatterer around the source and relay nodes and uniform angle of arrival (AOA) distribution, the spatial cross-correlation analysis is presented and extensive simulation studies are performed to determine the envelope correlation as a function of antenna spacing, mean AOA and angular spread. Error performance analysis for coherent binary and quaternary modulations are presented for fixed-gain amplify-and-forward (AF) and fixed decode-and-forward (DF) relaying with dual diversity maximal-ratio combiner (MRC) receiver array. Error probability in terms of bit error probability (BEP) and symbol error probability (SEP) is evaluated to study the effect of relevant parameters on the correlation performance. The presented results establish the fact that fixed DF relay network performs relatively well than fixed-gain AF relaying. Superior performance of dual-hop cooperative SIMO system over conventional single-hop SIMO system has also been observed.

An Analytical Model for the Performance Analysis of Concurrent Transmission in IEEE 802.15.4

Interference is a serious cause of performance degradation for IEEE802.15.4 devices. The effect of concurrent transmissions in IEEE 802.15.4 has been generally investigated by means of simulation or experimental activities. In this paper, a mathematical framework for the derivation of chip, symbol and packet error probability of a typical IEEE 802.15.4 receiver in the presence of interference is proposed. Both non-coherent and coherent demodulation schemes are considered by our model under the assumption of the absence of thermal noise. Simulation results are also added to assess the validity of the mathematical framework when the effect of thermal noise cannot be neglected. Numerical results show that the proposed analysis is in agreement with the measurement results on the literature under realistic working conditions.

Four-dimensional Rotations in Coherent Optical Communications

To model electromagnetic wave propagation for coherent communications without polarization dependent losses, the unitary 2 ×2 Jones transfer matrix formalism is typically used. In this study, we propose an alternative formalism to describe such transformations based on rotations in four-dimensional (4d) Euclidean space. This formalism is usually more attractive from a communication theoretical perspective, since decisions and symbol errors can be related to geometric concepts such as Euclidean distances between points and decision boundaries. Since 4d rotations is a richer description than the conventional Jones calculus, having six rather than four degrees of freedom (DOF), we propose an extension of the Jones calculus to handle all six DOF. In addition, we show that the two extra DOF in the 4d description represents transformations that are nonphysical for propagating photons, since they does not obey the fundamental quantum mechanical boson commutation relations. Finally, we exemplify on how the nonphysical rotations can change the polarization-phase degeneracy of well-known constellations such as single-polarization QPSK, polarization-multiplexed (PM-)QPSK and polarization-switched (PS-) QPSK. For example, we show how PM-QPSK, which is well known to consist of four polarization states each having four-fold phase degeneracy, can be represented as eight states of polarizations, each with binary phase degeneracy.

A QoS guarantee service serving model in LEO satellite networks based on differential game

Low Earth Orbit (LEO) satellites networks can provide multimedia service and plays an increasing1y important role in the exploitation of space. However, one of the challenges in LEO satellites networks is that the services are suffered from high symbol error, limited storage space and limited available energy. To analyze the performance of the service in LEO satellites networks, a model, based on differential game, is proposed for satisfying the QoS requirements of multimedia applications. The controller of our model is the transmitting rate and the object is to maximize the payoff depending on the error symbol rate, the available energy, the bandwidth and the process ability so as to guarantee the QoS service. In order to solve our built model, we use the Bellman theorem to make formulas on the trance of the optimal transmitting rate. Furthermore, simulation results verify that the service can be maximized by using our derived transmitting rate trance.

An Expression for Maximum Bit Error Probability Using the Amplitude Probability Distribution of an Interfering Signal and Its Application to Emission Requirements

It has been demonstrated that the amplitude probability distribution (APD) of an interfering signal provides an approximation for the bit error probability (BEP) of a radio communication system subjected to interference. The expression for BEP can be applied to the definition of emission limits for protecting a radio system. For communication systems employing multilevel modulation, the expression in some cases underestimates the maximum BEP when the interference is impulsive. In this paper, an improved BEP expression that removes the underestimation risk is derived considering the probability of multiple bit errors caused by one symbol error. On the basis of the new expression, a method of defining emission requirements is proposed by introducing a limit line that restricts the slope of the APD curve.

Physical Layer Design in Wireless Sensor Networks for Fading Mitigation

This paper presents the theoretical analysis, simulation results and suggests design in digital technology of a physical layer for wireless sensor networks. The proposed design is able to mitigate fading inside communication channel. To mitigate fading the chip interleaving technique is proposed. For the proposed theoretical model of physical layer, a rigorous mathematical analysis is conducted, where all signals are presented and processed in discrete time domain form which is suitable for further direct processing necessary for devices design in digital technology. Three different channels are used to investigate characteristics of the physical layer: additive white Gaussian noise channel (AWGN), AWG noise and flat fading channel and AWG noise and flat fading channel with interleaver and deinterleaver blocks in the receiver and transmitter respectively. Firstly, the mathematical model of communication system representing physical layer is developed based on the discrete time domain signal representation and processing. In the existing theory, these signals and their processing are represented in continuous time form, which is not suitable for direct implementation in digital technology. Secondly, the expressions for the probability of chip, symbol and bit error are derived. Thirdly, the communication system simulators are developed in MATLAB. The simulation results confirmed theoretical findings.