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with the energy and size constraint involved with the wireless sensor nodes it is very hard to implement powerful Error control Coding (ECC) techniques like Turbo codes which have shown to be capable of performing near Shannon limit on every sensor node. In this article an adaptive approach for the implementation of this Turbo codes is proposed where in the soft decision iterative decoder implementation is shifted to the base station of the network and a turbo encoder and error correction circuit are implemented at the sensor nodes. The performance of proposed system was evaluated by increasing the number of communication hops and different interleaver sizes. This proposed approach enhances the reliability of network communication by increasing the energy efficiency of the system. The reliability of proposed systems decision with MAX-Log-MAP and Log MAP decoding algorithms is tested. Keywords—ECC, Interleaver, MAP, Shannon limit, soft decision iterative decoder.

viii List of Figures viii

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of Thesis presented to UFSC as a partial fulfillment of the requirements for the degree of Doctor in Electrical Engineering NETWORK CODING BASED ON CLASSICAL ERROR CORRECTING CODES

of Dissertation presented to UFSC as a partial fulfillment of the requirements for the degree of Master in Electrical Engineering LDPC MULTILEVEL CODE DESIGN FOR PHYSICAL-LAYER NETWORK CODING Paulo Ricardo Branco da Silva November 27th, 2015 Advisor: Danilo Silva Area of concentration: Communications and Signal Processing

iii List of figures x List of abbreviations xiii List of notations xiv Chapter 1 Introduction 1 1.

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convolutional codes (TCC) are excellent error correcting codes, however TCC decoding based on A- Posteriori Probability (APP) algorithm is computationally complex and the complexity is not significantly reduced even if puncturing mechanism is used. To overcome the above disadvantage turbo codes need to be concatenated with other coding techniques such that the decoding complexity is significantly reduced and at the same time the Signal to Noise Ratio (SNR) can be as close to the Shannon limit as possible. In this paper one such modification is described, whereby convolutional coding as well as block coding technique of Zig-Zag codes will be used. First the simulation results of the encoder using MATLAB are presented and then the FPGA results using Artix-7 board will be shown.

\gls{HARQ} schemes are employed in mobile communication systems to reduce the residual Frame Error Rate (FER) after channel decoding. If decoding fails, the receiver requests the transmission of additional redundancy about these frames to improve the decoding success. Signaling is carried out over a feedback link from the receiver back to the transmitter. However, errors on the feedback link severely influence the behavior of the HARQ system and may degrade the overall system performance. In this contribution, the impact of HARQ signaling errors on the FER, the average number of HARQ transmissions per frame, and the system throughput is investigated. We derive analytical expressions for all performance measures based on FER simulations of the HARQ system with reliable feedback. The theoretical results are verified by the example of the LTE physical layer, however, they are also applicable to other communication systems. Moreover, target requirements for the maximum tolerable feedback error probabilities are derived which are used to develop design guidelines for HARQ feedback transceivers.

Write reliability is one of the major challenges in design of spin-transfer torque random access memory (STT-RAM) caches. To ensure design quality, error correction code (ECC) scheme is usually adopted in STT-RAM caches. However, it incurs significant hardware overhead. In observance of the dynamic error correcting requirements, in this work, we propose Sliding Basket - an adaptive ECC scheme to suppress the runtime write failures of STT-RAM cache with minimized hardware cost. Our simulation results show that compared to the STT-RAM caches with conventional ECC scheme, applying Sliding Basket can achieve up to 80.2% saving in ECC bit overhead, comparable write reliability and even better system performance.

With the widespread development of biometrics, concerns about security and privacy are increasing. In biometrics, template protection technology aims to protect the confidentiality of biometric templates (i.e., enrolled biometric data) by certain conversion. The fuzzy commitment scheme gives a practical way to protect biometric templates using a conventional error-correcting code. The scheme has both concealing and binding of templates, but it has some privacy problems. Specifically, in case of successful matching, stored biometric templates can be revealed. To address such problems, we improve the scheme. Our improvement is to coat with two error-correcting codes. In particular, our scheme can conceal stored biometric templates even in successful matching. Our improved scheme requires just conventional error-correcting codes as in the original scheme, and hence it gives a practical solution for both template security and privacy of biometric templates.

With the rapid development of network visual communications, there is an urgent need of effective and efficient video quality assessment (VQA) methods for quality control and resource allocation purposes. In this paper, a spatial and temporal reduced-reference (RR) VQA measure is combined with a robust video watermarking approach, leading to a quality-aware video (QAV) system. At the sender side, both intra- and inter-frame RR features are calculated from the original video based on statistical models of natural video. This is followed by error control coding to improve robustness. The encoded features are then embedded invisibly into the same video signal using a robust angle quantization index modulation based watermarking method in 3D discrete cosine transform domain. At the receiver side, the RR features are extracted and decoded from the distorted video and employed to predict the perceptual degradation of the video signal. Experimental results demonstrate the applicability of the proposed approach to a wide range of distortion types and levels.

With the rapid development of network visual communication technologies, digital video has become ubiquitous and indispensable in our everyday lives. Video acquisition, communication, and processing systems introduce various types of distortions, which may have major impact on perceived video quality by human observers. Effective and efficient objective video quality assessment (VQA) methods that can predict perceptual video quality are highly desirable in modern visual communication systems for performance evaluation, quality control and resource allocation purposes. Moreover, perceptual VQA measures may also be employed to optimize a wide variety of video processing algorithms and systems for best perceptual quality. This thesis exploits several novel ideas in the areas of video quality assessment and enhancement. Firstly, by considering a video signal as a 3D volume image, we propose a 3D structural similarity (SSIM) based full-reference (FR) VQA approach, which also incorporates local information content and local distortion-based pooling methods. Secondly, a reduced-reference (RR) VQA scheme is developed by tracing the evolvement of local phase structures over time in the complex wavelet domain. Furthermore, we propose a quality-aware video system which combines spatial and temporal quality measures with a robust video watermarking technique, such that RR-VQA can be performed without transmitting RR features via an ancillary lossless channel. Finally, a novel strategy for enhancing video denoising algorithms, namely poly-view fusion, is developed by examining a video sequence as a 3D volume image from multiple (front, side, top) views. This leads to significant and consistent gain in terms of both peak signal-to-noise ratio (PSNR) and SSIM performance, especially at high noise levels.

With the increasing demand for high resolution, large scale images and fast downlink data rates of remote-sensing satellites, the higher decoding speed of BM(Berlekamp Massey) algorithm of the satellite receivers employing RS(Reed Solomon) codes as forward error correction codes is needed. A new improved BM algorithm is presented and its explicit proofs are given. Taking RS(255, 223) of CCSDS standard as the research object, a great number of simulation experiments are carried out using MATLAB and FPGA to verify the algorithm. The experiment results show that the improved BM algorithm is more simple and feasible, and its decoding speed is increased by 6%.

With the emergence and popularity of identity verification means by biometrics, the biometric system which can assure security and privacy has received more and more concentration from both the research and industry communities. In the field of secure biometric authentication, one branch is to combine the biometrics and cryptography. Among all the solutions in this branch, fuzzy commitment scheme is a pioneer and effective security primitive. In this paper, we propose a novel binary length-fixed feature generation method of fingerprint. The alignment procedure, which is thought as a difficult task in the encrypted domain, is avoided in the proposed method due to the employment of minutiae triplets. Using the generated binary feature as input and based on fuzzy commitment scheme, we construct the biometric cryptosystems by combining various of error correction codes, including BCH code, a concatenated code of BCH code and Reed-Solomon code, and LDPC code. Experiments conducted on three fingerprint databases, including one in-house and two public domain, demonstrate that the proposed binary feature generation method is effective and promising, and the biometric cryptosystem constructed by the feature outperforms most of the existing biometric cryptosystems in terms of ZeroFAR and security strength. For instance, in the whole FVC2002 DB2, a 4.58% ZeroFAR is achieved by the proposed biometric cryptosystem with the security strength 48 bits.

With the development of computers and the Internet, digital multimedia can be distributed and pirated easily. Watermarking is a useful technique for multimedia copyright protection. In this paper, we develop a robust video watermarking system. It consists of two components, that is, watermarking embedder and watermarking detector. In the embedder, we insert a watermark pattern into video frames according to a watermark payload. The watermark pattern is generated from a pseudo-random noise sequence generator using the spread spectrum technique. User and copyright information are mapped to a binary sequence and then encrypted with advanced encryption standard and encoded/protected by convolutional error correction code to produce a watermark payload. The watermark pattern is weighted and embedded to each frame to meet perceptual requirements. In addition, the video is slightly geometrically manipulated in order to defend possible collusion attacks. The detector extracts the watermark from the candidate video. Kanade–Lucas–Tomasi feature tracker is used to register the candidate video with respect to the original video to enhance the correlation with the reference. The cross-correlation sequence is binarized, error correction code decoded, and decrypted. The experimental results show that the proposed video watermark system is very robust to not only geometric attack but also collusion attacks, and that it is perceptually invisible to human vision system. Copyright © 2011 John Wiley & Sons, Ltd.

With significant research being conducted in Ultra Wideband communications to increase error performance, this paper proposes a combination of user multiplexing and data encoding to achieve a BER improvement. Through the use of non-binary turbo coding, data is modulated to form a time hopping code which is applied to a time-reversed UWB system. Comparative results with conventional binary coding are given, showing the possibility for BER improvements in systems with a low number of users. Slight performance degradations for a large number of users exist. The effects of a user applying turbo coding on other users not applying forward error correction is also studied.

With much advancement in the field of nanotechnology, bioengineering, and synthetic biology over the past decade, microscales and nanoscales devices are becoming a reality. Yet the problem of engineering a reliable communication system between tiny devices is still an open problem. At the same time, despite the prevalence of radio communication, there are still areas where traditional electromagnetic waves find it difficult or expensive to reach. Points of interest in industry, cities, and medical applications often lie in embedded and entrenched areas, accessible only by ventricles at scales too small for conventional radio waves and microwaves, or they are located in such a way that directional high frequency systems are ineffective. Inspired by nature, one solution to these problems is molecular communication (MC), where chemical signals are used to transfer information. Although biologists have studied MC for decades, it has only been researched for roughly 10 year from a communication engineering lens. Significant number of papers have been published to date, but owing to the need for interdisciplinary work, much of the results are preliminary. In this survey, the recent advancements in the field of MC engineering are highlighted. First, the biological, chemical, and physical processes used by an MC system are discussed. This includes different components of the MC transmitter and receiver, as well as the propagation and transport mechanisms. Then, a comprehensive survey of some of the recent works on MC through a communication engineering lens is provided. The survey ends with a technology readiness analysis of MC and future research directions.

With much advancement in the field of nanotechnology, bioengineering and synthetic biology over the past decade, microscales and nanoscales devices are becoming a reality. Yet the problem of engineering a reliable communication system between tiny devices is still an open problem. At the same time, despite the prevalence of radio communication, there are still areas where traditional electromagnetic waves find it difficult or expensive to reach. Points of interest in industry, cities, and medical applications often lie in embedded and entrenched areas, accessible only by ventricles at scales too small for conventional radio waves and microwaves, or they are located in such a way that directional high frequency systems are ineffective. Inspired by nature, one solution to these problems is molecular communication (MC), where chemical signals are used to transfer information. Although biologists have studied MC for decades, it has only been researched for roughly 10 year from a communication engineering lens. Significant number of papers have been published to date, but owing to the need for interdisciplinary work, much of the results are preliminary. In this paper, the recent advancements in the field of MC engineering are highlighted. First, the biological, chemical, and physical processes used by an MC system are discussed. This includes different components of the MC transmitter and receiver, as well as the propagation and transport mechanisms. Then, a comprehensive survey of some of the recent works on MC through a communication engineering lens is provided. The paper ends with a technology readiness analysis of MC and future research directions.