Benefits of Highly Synchronizing Huffman Encoding for Reducing Errors in Wireless Transmission of ECG Data

With technology scaling and complexity, better error detection and correction mechanisms within chips and systems are becoming increasingly important in order to provide sufficient protection against both soft and hard errors. Verifying the correctness of error detection circuits and ensuring they provide enough design coverage is a hard problem which usually involves substantial amount of manual work. This problem is even more challenging in the presence of different design methodologies, such as with the inclusion of third party IP blocks where functional descriptions of logic designs may not be available. This paper addresses the problem by proposing a completely automated RTL-based verification flow for error detection and correction circuits. Several related challenges are solved: first, that of identification of potential error detection circuits in logic designs where no functional description or methodology hints are given. Second, identification of structures of the latches that are potentially protected by such error detection circuits. Third, using formal verification for ensuring that the implemented circuits for resiliency indeed detect all single bit errors in the latches they are intended to cover. The approach is described with parity detection as an example, although it is extensible to other coding methods such as ECC and state orthogonality checking. Novel algorithms are given and results on industrial designs are presented.

In this thesis, a jointed preamble/boundary detection and fractional CFO estimation design is presented which supports dual SC/HSI modes of IEEE 802.15.3c applications. Based on correlation based algorithms which utilizes the structure of preamble, an efficiency architecture is proposed which realizes synchronization detection with a sequential detection scheme and a single hardware for dual SC/HSI modes and three detection operations. In order to achieve the requirement of sampling frequency, the baseband design is 8x parallelism and is operating at 333 MHz clock rate. The achieved bit error rate (uncoded) at 12 dB SNR for SC and HSI modes are 8.92×10-4 and 1.43×10-2, respectively. The proposed architecture of synchronization detection is implemented using 65 nm 1P9M CMOS process and the total gate count is 189k with power consumption of 60.16 mW including memory elements which occupies 63.26 % and can be shared with the frequency domain equalizer. Moreover, the power consumption is saved 42.5 % by applying low power techniques.

A hybrid direct-sequence/frequency-hopping spread-spectrum communication modem for burst format transmission of digital data has been developed. A burst consists of a short synchronisation preamble and the data packet. Data modulation is accomplished by assignment of pairs of pseudonoise sequences with low crosscorrelation for message ones and zeros. The spreading code chip pattern is changed from bit to bit in both the preamble and the message portion of a burst. Receiver signal processing is based on the application of surface-acoustic-wave (SAW) elastic convolvers to programmable matched filtering. The performance of the system in an additive white Gaussian noise channel is analysed, measures of performance being the probability of burst loss and the bit error probability in the case of ideal synchronisation. Evaluations for a particular design are presented, and some experimental results obtained with a test system are shown for comparison.

Emerging wireless technologies will play an important role in home network applications. Chaotic UWB technology has several inherent properties that are suited to home networks. In particular, applications have been focused such as low power consumption, low complexity, and low cost. In this paper, we describe the chaotic signal based UWB systems and the optimum sample number to minimize the bit error rate of the chaotic on-off keying. Moreover, we propose new scheme using the optical orthogonal code based chaotic on-off keying in an asynchronous channel for simultaneously operating piconets environment: all users are allowed to transmit their signal at any time, and moreover there is usually no network synchronization or coordinator among users.

The purpose of this research is to compare between quadratic and logistic discrimination function, also to identify the best method in discrimination which helps us to classify the data correctly. A several stages are starting from stratified sampling; classification errors and error rate if the pre-probability is equal and unequal by containing a few errors. Our choice of the correct path in analyzing the data helped us to identify the reasons that increase the errors in classification. In this study, we used some statistical measurements in terms of, the stratified sample, classification errors and the percentage of errors. The percentage of errors in the pre-probability is equal and unequal when the accumulation of errors in the square discrimination function was less than the accumulation of errors in the logistic discrimination function when the probability is equal, but when the probability is not equal, the results of the square function were much better than the square discrimination function. However, the accumulation of errors in the quadratic function is less than the accumulation of errors in the logistic function.

In this paper, we use post processing methods to compensate the bit errors occurred in watermark embedding and extracting. Forward error correction (FEC)-based and chirp-based techniques are applied to encode and shape the embedded watermark message so that even at the presence of some bit error rates (BERs) in the extracted watermark, the watermarking algorithm be able to successfully estimate the correct embedded watermark message. Repetition and Bose-Chaudhuri-Hocquenghem (BCH) codings are used as two well-known FEC schemes, and discrete polynomial transform (DPPT) and Hough-Radon transform (HRT) are utilized as two chirp detectors in chirp-based watermarking. Robustness of all the proposed post processing methods are tested for checkmark benchmark attacks, and we found that the chirp-based watermarking using the DPPT chirp detector offers the highest watermark extraction rate, and the best bit error compensation even at BERs of higher than 17%.

A Physical Unclonable Function (PUF) is a die specific random function that can be used in a number of secure IC applications including die identification/authentication and key generation. At the core of a silicon PUF is a circuit (the PUF core) that generates random bits. These bits are like a silicon biometric, unique across dies, but can be reliably reproduced multiple times on a die across voltage and temperature variations and aging. In this thesis, we discuss various aspects of a PUF design, with a strong focus on circuit details. We describe the properties and the figures of merit of a PUF and then compare various PUF core implementations. We identify the biggest design challenges and provide several solutions. Results in this work are supported by measurement data from testchips designed in 65nm bulk CMOS. We provide an apples-to-apples comparison of various PUF implementations. We demonstrate that while adequate randomness and uniqueness is achievable for most PUF implementations, achieving high reliability is a challenge. The conventional method to achieve high reliability is to use error correcting codes (ECC). Unfortunately, the overheads associated with these techniques grows very quickly with error correction capability. Alternately, researchers have proposed several error reduction techniques to minimize the use of error correction. In this work, we evaluate four orthogonal and complementary error reduction techniques. Two of these techniques, categorized as extrinsic techniques, are multiple evaluation (ME) and activation control (AC) and are able to reduce errors in PUF response by ~70-80%. The other two techniques, categorized as intrinsic, are post-silicon selection (PSS) and directed accelerated aging (DAA) and show ~100% correction of errors. As a proof of concept prototype, we describe a self-contained, BIST-controlled key-generator that implements the PSS technique to autonomously generate bits with a bit error rate < 5 * 10^-9, equivalent to a 128-bit key error rate < 10^-6. We also describe a realization of a strong-PUF that uses these highly reliable bits in conjunction with an Advanced Encryption Standard (AES) primitive.

The aim of this thesis is to construct toolsets that support the Synchronous Java programming language, an extension to the Java language that introduces a new method of synchronization between threads. The contributions of this thesis include a State Space Analyzer (SSAS) and a Deadlock Detector for Synchronous Java (DDSJ). As the first tool I developed an analyzer, the SSAS, that explores all the reachable states and all the possible execution paths of an sJava model. This exploration aims at the analysis of the communication between active threads and the detection of deadlocks in a given sJava model. When a deadlock is encountered, the toolset generates the error traces that help the developers to examine how the deadlocks were produced in the input model. The analyzer also generates the state space of the system model and a graphical representation of this state space. In the second toolset, the DDSJ, I developed an approach that reduces the number of states when verifying an sJava program in Bandera and Bogor, which are the toolsets that support the verification of Java models. If errors are detected when verifying an sJava model, DDSJ generates a counter-example that allows developers to simulate the execution of the given model to study how errors were produced. The outcomes of this thesis give the Synchronous Java developers more confidence in using this programming language. These toolsets provide a possibility to examine sJava programs and to refine them before they can be delivered as product.

Probabilistic nature of magnetic tunnel junctions (MTJs) poses a new type reliability challenges for spin-transfer-torque MRAM (STT-MRAM). Switching current and thermal barrier need to be co-optimized to control bit error rate margins of STT-MRAM. This requires deeper understanding about thermal disturbance and soft write errors of MTJ devices. In this tutorial, we review basic mechanisms that govern the bit error rates of STT-MRAM and discuss the effect of the probabilistic nature of MTJ devices on STT-MRAM reliability engineering.

Data Processing Units for scientific space mission need to process ever higher volumes of data and perform ever complex calculations. But the performance of available space-qualified general purpose processors is just in the lower three digit megahertz range, which is already insufficient for some applications. As an alternative, suitable processing steps can be implemented in hardware on a space-qualified SRAM-based FPGA. However, suitable devices are susceptible against space radiation. At the Institute for Communication and Network Engineering a fault-tolerant, network-based communication architecture was developed, which enables the construction of processing chains on the basis of different processing modules within suitable SRAM-based FPGAs and allows the exchange of single processing modules during runtime, too. The communication architecture and its protocol shall isolate non SEU mitigated or just partial SEU mitigated modules affected by radiation-induced faults to prohibit the propagation of errors within the remaining System-on-Chip. In the context of an ESA study, this communication architecture was extended with further components and implemented in a representative hardware platform. Based on the acquired experiences during the study, this work analyses the actual fault-tolerance characteristics as well as weak points of this initial implementation. At appropriate locations, the communication architecture was extended with mechanisms for fault-detection and fault-differentiation as well as with a hardware-based monitoring solution. Both, the former measures and the extension of the employed hardware-platform with selective fault-injection capabilities for the emulation of radiation-induced faults within critical areas of a non SEU mitigated processing module, are used to evaluate the effects of radiation-induced faults within the communication architecture. By means of the gathered results, further measures to increase fast detection and isolation of faulty nodes are developed, selectively implemented and verified. In particular, the ability of the communication architecture to isolate network nodes without SEU mitigation could be significantly improved.

In this thesis, we cope with the fundamental mathematical and physical problems of the space-time-Doppler UWB system design for fading channels: multi-input multi-output (MIMO) wireless communication with adaptive filtering. The estimation algorithm from equalizer providing an accurate parameters estimate is investigated. UWB radio is a fast emerging technology with uniquely attractively features inviting major advances in wireless communications, networking, radar, imaging, and positioning systems. By its rule-making proposal in 2002, the Federal Communications Commission (FCC) in the United States essentially unleashed huge new bandwidth (3.6-10.6 GHz) at the noise floor, where UWB radios overlaying coexistence RF systems cerate using low-power ultra-short information bearing pulses. Right now, there are three basic types of UWB: multiband OFDM UWB (MB-OFDM UWB), impulse-UWB (I-UWB), and direct sequence UWB (DS-UWB). We focus on I-UWB and MB-OFDM-UWB, and compare their performance. A simple means for spreading the spectrum of low duty cycle pulse trains is time hopping (TH), with pulse position modulation (PPM) for data modulation at the rate of many pulses per data bit. The main contribution of this thesis for I-UWB is the design of leading edge detectors, coherent correlation detector (CCD), and pilot performance enhancement compared with different Rayleigh and Ricean fading conditions. For MB-OFDM UWB, we have considered the performance analysis and design criteria of MIMO OFDM UWB systems for high data-rate wireless transmission. The signal processing of frame detection, time synchronization, frequency synchronization, channel estimation, synchronization tracking using pilot subcarriers and 2-D MIMO detection algorithms is discussed. The main contributions of this thesis are 1) Compared with receiver employing the Maximum Likelihood (ML) detector, the receiver employing a low-complexity linear Minimum Mean Square Error (MMSE) demodulator can perform a limited performance loss in spatially uncorrelated channels. 2) Due to the operations of spreading and dispreading combined with MMSE-based frequency domain equalization, the adverse effects of the low-SNR subcarriers on the average BER performance are potentially improved. This is a direct consequence of spreading, because even if the signal corresponding to a specific chip is obliterated by a deep frequency domain channel fade, after dispreading these effects are spread over the Walsh-Hadamard Transform (WHT) length. Hence there is a high chance of still recovering all the partially affected subcarrier symbols without errors. 3) As a test case, the OFDM-based 200 Mb/s MB-UWB network (IEEE 802.15.3a) are considered, but the simulation results are shown above section. 4) The simulation channel can be easily applied to NOS and NLOS situation with WHT transformation from Simulink model. The fading channels of UWB with low/high signal to noise ratio (SNR), multipath effects, and multiuser interference may introduce large errors in location. The location engine performs the following tasks: █ Data fusion techniques: Different data fusion techniques are implemented using Time Of Arrival (TOA), Angle Of Arrival (AOA), or a combination of both. █ Channel modeling: A multipath, multiuser channel environment is created that models path loss, shadowing, Rayleigh fading, and Doppler frequency effects. █ Parameter estimation: TOA and AOA estimation algorithms are implemented as part of the location finding engine. Different variations of algorithms are implemented for performance and comparison purposes. █ Configuring the physical layer for different wireless networks. Among the programmable parameters are spreading factor, packet size, training length, constellation type, modulation technique, carrier frequency, level of transmitted signal power, and the number of antennas at the transmitter for both sides. █ Configuring the mobile user conditions. The wireless channel models depend on the Doppler frequencies present in the environment. The Doppler frequency depends on the mobile speed and carrier frequencies as input and generates a Rayleigh fading channel with the U-shape Doppler spectrum. █ Configuring the environmental parameters and network geographical structure. One of the factors affecting the performance of the wireless location system is the environment type (e.g., bad urban, urban, suburban, or rural area). For example, in a bad urban area with many blocking objects and buildings, non-line of sight (NLOS) effects plays an important role in the estimation accuracy.

Robotic technologies will continue to enter new applications in addition to automated manufacturing and logistics. Once mobile robots can also operate outside of today's special facilities, they have the potential to relieve us of dirty and dangerous labor in various areas. However, for this purpose, these machines will need to be able to navigate autonomously in complex natural, urban, and industrial settings. This thesis addresses the development of locomotion skills for legged robots in challenging environments. Our work focuses on perceptive locomotion where exteroceptive sensing of the surrounding is exploited to plan and control the robot’s motion. This enables quadrupedal robots to negotiate rough terrain through carefully selected contacts. In this work, we evaluate different sensing technologies and analyze their performance for local dense terrain mapping on a mobile robot. We include special conditions such as close range objects and the influence of ambient light as we find them in real-world applications. By modeling the error characteristics of the sensors, the robot can judge the quality of the resulting terrain reconstruction. As the robot moves, the surrounding is continuously mapped to capture new areas and update regions which have changed. We contribute with a mapping framework that models the terrain from a robot-centric perspective. To this end, we present a novel approach for the error propagation from the robot's state estimation to the representation of the map. This formulation allows for robust and high-rate local mapping that is independent of a global localization method. We introduce our approach to locomotion planning, which finds safe footholds along with collision-free swing-leg motions, leveraging the generated terrain map. A nonlinear optimization finds postures that respect kinematic and stability constraints. We experimentally verify this work with torque-controllable quadrupedal robots that autonomously traverse obstacles, such as rubble, steps, gaps, and stairs without prior knowledge of the scene or any additional equipment. The locomotion planner re-plans its motion at every step in real-time, to cope with disturbances and dynamic environments. For the control of the legged robot, we contribute architecturally to the versatile and task-oriented motion execution. This method enables the robust tracking of motion plans, even with significant mismatches between the models and reality. In addition to rough terrain locomotion, we demonstrate the integration of our method for applications, such as whole-body stair climbing, manipulation, jumping, docking, inspection, payload delivery, dancing, and more. Our approach is thoroughly validated with the quadrupedal robot ANYmal in realistic long-term missions for autonomous industrial inspection and search and rescue. Finally, we extend our work with the design and implementation of a collaborative navigation framework for ground and flying robots. The ground vehicle utilizes the data captured by the flying robot to navigate uncharted…

In this paper, we use eight transmitter antennas and eight receiver antennas as the circle antenna arrays. Shooting and bouncing ray/image(SBR/Image)techniques combining with antenna pattern are used to calculate the impulse response in indoor wireless environment. Beamforming techniques are employed to reduce the multi-path effect of the channel and bit error rate (BER). We adjust the excitation amplitude and feed length of each array element to synthesize the pattern of the antenna array by using the genetic algorithms (GA) and self-adaptive dynamic differential evolution (SADDE). Numerical results show that SADDE algorithm outperforms GA algorithm in terms of bit error rate performance and convergence speed.

The use of codes in forward error correction and decision feedback schemes is analysed. Various comparisons of the two types of error control scheme are undertaken when finite and infinite repetitions are possible and when the feedback channel can be considered noisy or noiseless. These comparisons are based on the consideration of both the average information bit error probability and transmission efficiency to obtain the overall effectiveness of the error control schemes.

In this paper, a new approach to remove noise present in ECG signal is proposed. Baseline wander and high frequency noise is eliminated by using computationally efficient linear phase filter ie. interpolated finite impulse response (IFIR) filter. The IFIR filter is designed by using Kaiser window function to achieve high stop band attenuation. As compared to other methods, the technique presented could achieve a reduction in computational complexity by 80.14 percent. Data compression is also performed in this study using wavelet packet decomposition along with Run-length encoding. Run-length encoding is used to improve the compression performance. For evaluation of the performance of IFIR filter, computational cost reduction (CRC) parameter is used, which directly depended on multipliers and adders. Different fidelity factors are considered to evaluate the performance of the proposed data compression method, viz., compression ratio (CR), signal to noise ratio (SNR), retained energy (RE) and percent root mean square difference (PRD), their magnitude being 25.13, 38.93, 99.10 and 1.75, respectively. MIT-BIH arrhythmia database has been utilized to judge the entire set of computations mentioned above noise removal and ECG signal compression. This work also includes beat detection of original and reconstructed signals. Simulated results show that decompressed signal is a replica of the input signal.