Frame Synchronization

The lack of effective contention resolution mechanisms in the optical domain presents dynamic optical switching architectures with a hard dilemma between high loss (when adopting one-way reservations) and high delay (when using two-way reservations). In this work we evaluate an alternative hierarchical network architecture, which achieves a satisfactory compromise by partitioning the network into a number of geographically limited domains operating in slot and frame synchronous mode where two-way reservations are effective.

A wide variety of systems require reliable person recognition schemes to either confirm or determine the identity of an individual requesting their services. The purpose of such schemes is to ensure that only a legitimate user and no one else access the rendered services. Examples of such applications include secure access to buildings, computer systems, laptops, cellular phones, and ATMs. Face can be used as Biometrics for person verification. Face is a complex multidimensional structure and needs a good computing techniques for recognition. We treats face recognition as a two-dimensional recognition problem. A well-known technique of Principal Component Analysis (PCA) is used for face recognition. Face images are projected onto a face space that encodes best variation among known face images. The face space is defined by Eigen face which are eigenvectors of the set of faces, which may not correspond to general facial features such as eyes, nose, lips. The system performs by projecting pre extracted face image onto a set of face space that represent significant variations among known face images. The variable reducing theory of PCA accounts for the smaller face space than the training set of face. A Multire solution features based pattern recognition system used for face recognition based on the combination of Radon and wavelet transforms. As the Radon transform is in-variant to rotation and a Wavelet Transform provides the multiple resolution. This technique is robust for face recognition. The technique computes Radon projections in different orientations and captures the directional features of face images. Further, the wavelet transform applied on Radon space provides multire solution features of the facial images. Being the line integral, Radon transform improves the low-frequency components that are useful in face recognition.

NEXCODE is a project promoted by the European Space Agency aimed at research design development and demonstration of a receiver chain for telecomm and links in space missions including the presence of new short low-density parity-check codes for error correction. These codes have excellent performance from the error rate viewpoint but also put new challenges as regards synchronization issues and implementation. In this paper after a short review of the results obtained through numerical simulations we present an overview of the breadboard designed for practical testing and the test-plan proposed for the verification of the breadboard and the validation of the new codes and novel synchronization techniques under relevant operation conditions.

This paper addresses the carrier-phase estimation problem under low SNR conditions as are typical of turboand LDPC-coded applications. In [1], [2] closed-loop carrier synchronization schemes for error-correction coded BPSK and QPSK modulation were proposed that were based on feeding back hard data decisions at the input of the loop, the purpose being to remove the modulation prior to attempting to track the carrier phase as opposed to the more conventional decisionfeedback schemes that incorporate such feedback inside the loop. In this paper, we consider an alternative approach wherein the soft information from the iterative decoder of turbo or LDPC codes is instead used as the feedback. Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.

In traditional receiver architectures, symbol acquisition and tracking are performed using phase lock techniques that are independent of the channel-code decoding process. In [1] feedback from the constraint-node side of a bi-partite graph is used to estimate symbol frequency and timing offset in a baseband pilotless transmission. In [2] soft information feedback from an LDPC decoder is used to recover carrier phase information under the assumption of perfect symbol timing. In this paper we address the problem of joint carrier-phase and symbol timing recovery. The proposed system is able to perform within 0.3 [dB] of the code performance with perfect knowledge of carrier phase and symbol timing.

In traditional receiver architectures, symbol acquisition and tracking are performed using phase lock techniques that are independent of the channel-code decoding process. In [1] feedback from the constraint-node side of a bi-partite graph is used to estimate symbol frequency and timing offset in a baseband pilotless transmission. In [2] soft information feedback from an LDPC decoder is used to recover carrier phase information under the assumption of perfect symbol timing. In this paper we address the problem of joint carrier-phase and symbol timing recovery. The proposed system is able to perform within 0.3 [dB] of the code performance with perfect knowledge of carrier phase and symbol timing.

This paper addresses the carrier-phase estimation problem under the low SNR conditions often encountered in turbo and LDPC-coded applications. In [1] a decision-directed carrier synchronization (DDCS) circuit that uses soft information from an iterative LDPC decoder was presented for BPSK and QPSK constellations with constant phase offsets. In this work, we present a method that is able to handle arbitrary constellations with a random-walk phase noise process. Loop SNR equations are derived and the performance for different constellations is shown. An extension of the DDCS algorithm is described that uses a search and tracking method based on measuring the number of satisfied LDPC constraint-node equations equations at the decoder and is able to track arbitrary carrier phase.

Timing recovery and channel decoding are traditionally performed independently. However, we show here that the information generated during the iterative decoding of Low-Density Parity-Check (LDPC) coded data can be fed back to the timing recovery circuit to enable accurate estimation of frequency and phase errors without the need for any pilot symbols. We describe a method capable of handling large offsets with complexity that grows linearly with offset size. Combining the LDPC constraint node observations with a properly calibrated phase locked loop allows successful tracking of a constant time delay, a frequency offset and a random phase walk.

I would like to thank my parents Anahí and Enrique, my sisters Ana Sofía and Maria Clara, my grandparents Memé, Pepé, Blanca and Marcelo, my uncles, aunts and cousins, for their constant support and love, that made all these years of work away from home go by as if I had never left them. When I arrived at UCLA, Prof. John Villasenor welcomed me to his group, helping me to begin my academic life by working in exciting and practical problems. Our initial work together led to a series of projects that became the core of my thesis work. I am extremely grateful for his help and guidance. Prof. Richard Wesel, was extremely important throughout my career. He introduced me to coding theory, first as a professor, and later as my co-advisor. His constant support in good times and especially in the difficult times that I have faced in the past years, were what drove me to never give up and successfully complete this doctoral degree. I am forever thankful for all his help and support, both in my personal and academic life. I would also like to thank my committee members Prof. Mihaela van der Schaar and Prof. Mario Gerla for their invaluable feedback to make this a better dissertation. Throughout these years in southern California, I received the help and support of many people, too many perhaps to fit in these two pages of acknowledgments. I will begin to thank the people at U.C. Irvine starting with the Maranesi family, who were like a second family to me, Ashish Bhargave, Raja Jurdak, Ali Hamadeh, Daniel Gilden, Maria Cruz Villa-Uriol, Olgu Icoz, and all the other amazing people that I met there. I especially want to thank my friend, and future best-man Enis ix Akay. His friendship and support not only changed my life as student, but taught me that the word brother has no relation to where we are born or raised, or what our culture or religion is. Our friendship went beyond all these mundane differences and is a bond that will remain forever. Life in Los Angeles has been a very gratifying experience. I met great people at school but I was also able to meet amazing friends outside campus. I would like to thank Mario Blaum for all of his support and words of advice. Meeting Mario and being able to work with him encouraged me to continue in the pursuit of my degree. I want to thank Leonel Lopez Lavalle, Andres Pascuzzi, Roman Sacyk, Rogelio Adobatti, and the many others who constantly made me feel at home. I want to specially thank Miguel Griot for being a great roommate, co-worker and teammate in our UCLA Gauchos team. I also want to thank Andres Vila Casado, who not only inspires our research group with his never ending ideas, but who also became a great friend throughout these years. Working together with him and Miguel, was one of the most enjoyable parts of my last years at UCLA. We created an extremely enjoyable work environment that will be really hard for me to find again. I am grateful to all the people at Image Lab including Michael Smith, David

The enclosed files contain Matlab code for the simulation of digital predistortion (DPD) mitigation techniques in a 3-carrier transparent satellite link. All carriers have the same data rate and modcod, that is, the same modulation and code rate. The carrier signals are compliant with DVB-S2 specifications [1, 2]. 1 Description The enclosed Matlab files are implementations of different DPD mitigation techniques in a 3-carrier satellite link. The carriers are frequency spaced to 1.25 times the symbol rate. Each carrier has a analog bandwidth corresponding to 7 MHz, the pulse shape filter is a SRRC with 0.25 roll-off factor, and the IMUX, OMUX 3 dB bandwidths are 28 and 32 MHz, respectively. The high power amplifier at the satellite transponder is simulated using a Saleh model. The implemented DPD schemes are: 1. MIMO memory polynomial data DPD [3]. 2. MIMO reduced-complexity memory polynomial data DPD [4]. 3. MIMO Symbol Rate Signal DPD [5]. 2 Size The total size of the enclosed file...

Virtual Reality (VR) applications have been powered traditionally by high-end graphics workstations or supercomputers. But recently, clusters of commodity computers (PCs, Macintoshes, low cost workstations) have become a practical alternative. The advantages of a commodity cluster include low cost, flexibility, access to technology, and performance scalability. The main goal of our proposal is offer both a High Performance Computing System (HPC) and High Availability (HA) simulation environment supporting the features demanded by Virtual Reality applications. In this paper we will approach the challenges related to manage and control this distributed environment in a unique and integrated interface, offering to the user better use of the available distributed resources. Design issues and results are presented considering architectural options and final applications.

The study presented in this paper consists in the modeling and optimization of the performance of the control of an induction motor (IM) by the application of the sensorless field oriented control (SFOC), using the strategy of the discontinuous pulse width modulation (DPWM) to switch the transistors which form the three-phase voltage source inverter (3Ph_VSI). The latter gives a reduction in the number and the switching losses compared to the space vector modulation (SVPWM). This leads to improve the performance of the IM. The proposed system has many advantages; provides for the decrease in noise, presents an increase in reliability and makes the material less expensive. The study of this control is done in order to show the efficiency and robustness of the method during variations in speed and torque.

This paper examines advanced modulation and coding schemes that are critical for future-ready wireless access technologies. It focuses on techniques such as higher-order QAM, LDPC, and polar codes that enhance data rates, spectral efficiency, and robustness against noise. By addressing challenges in reliability, latency, and bandwidth utilization, these innovations support the performance demands of 5G, 6G, and beyond, enabling ultra-reliable, high-capacity wireless communication for next-generation networks and applications.

Communication systems have multiple performance metrics, such as flexibility, scalability and efficiency. The latter is however one of the oldest concerns of communication technology and still very relevant, for example in satellite communications. An efficiency improvement directly translates to the significant improvement in operational expenditures while sometimes also allowing capital expenditure gains. While efficiency or throughput gain within a given frequency bandwidth is typically the ultimate purpose of new signal processing techniques such as predistortion techniques, publications mostly focus on the signal-to-noise ratio (SNR) gain, as this is easier to measure and does not depend on the granularity of the applicable modulation and coding technology. Furthermore, it is commonly assumed that this SNR gain must be significantly large, e.g. larger than 1 dB, to yield a measurable guaranteed throughput gain. This motivates a revisit of using SNR gains as the benchmark for pr...

We consider in this paper the problem of blind frame synchronization of systems using Reed-Solomon (RS) codes and other related families. We present first of all three techniques of blind frame synchronization based on the non-binary parity check matrix of RS codes. While the first two techniques involve the calculation of hard and soft values of the syndrome elements respectively, the third one perform an adaptation step of the parity check matrix before applying the soft criterion. Although RS codes are constructed from non-binary symbols, we show in this paper that it is also possible to synchronize them using the binary image expansion of their parity check matrix. Simulation results show that the synchronization algorithm based on the adaptation of the binary parity check matrix of RS codes has the best synchronization performance among all other techniques. Furthermore, the Frame Error Rate (FER) curves obtained after synchronization and decoding are very close to the perfect synchronization curves.

Arm, UK ‡ , Qualcomm NJ, USA § Abstract-Frame synchronization is an important functionality that should be supported in the design of an LTE baseband receiver. Detecting the start of a frame is regularly repeated during transmission and to identify the cells of the network. Typically, the synchronization is performed using correlationbased methods that incur a large number of multiplications and thus increase the power consumption and hardware complexity. Approaches to reduce the rate of multiplications come at the expense of reduced performance of the algorithm. In this paper, we present a multiplication-free synchronization algorithm that is based on K-means clustering and distributed arithmetic and uses the primary synchronization signal (PSS). We also show through simulations that the immense improvement in power consumption and hardware complexity does not entail a degradation in performance compared to current synchronization techniques.

Conventional correlation-based frame synchronization techniques can suffer significant performance degradation over multi-path frequency-selective channels. As a remedy, in this paper we consider joint frame synchronization and channel estimation. This, however, increases the length of the resulting combined channel and its estimation becomes more challenging. On the other hand, since the combined channel is a sparse vector, sparse channel estimation methods can be applied. We propose a joint frame synchronization and channel estimation method using the orthogonal matching pursuit (OMP) algorithm which exploits the sparsity of the combined channel vector. Subsequently, the channel estimate is used to design the equalizer. Our simulation results and experimental outcomes using software defined radios show that the proposed approach improves the overall system performance in terms of the mean square error (MSE) between the transmitted and the equalized symbols compared to the conventional method.

Ultra-high-resolution tiled display walls are typically driven by a cluster of computers. Each computer may drive one or more displays. Synchronization between the computers is necessary to ensure that animated imagery displayed on the wall appears seamless. Most tiled display middleware systems are designed around the assumption that only a single application instance is running in the tiled display at a time, therefore synchronization can be achieved with a simple solution such as a networked barrier. When a tiled display has to support multiple applications at the same time, the simple networked barrier approach does not scale. In this paper we propose and experimentally validate two synchronization algorithms to achieve low-latency inter-tile synchronization for multiple applications with independently varying frame-rates. The Two-Phase algorithm is more generally applicable to various high-resolution tiled display systems. The One-Phase algorithm provides superior results but r...

Ultra-high-resolution tiled display walls are typically driven by a cluster of computers. Each computer may drive one or more displays. Synchronization between the computers is necessary to ensure that animated imagery displayed on the wall appears seamless. Most tiled display middleware systems are designed around the assumption that only a single application instance is running in the tiled display at a time, therefore synchronization can be achieved with a simple solution such as a networked barrier. When a tiled display has to support multiple applications at the same time, the simple networked barrier approach does not scale. In this paper we propose and experimentally validate two synchronization algorithms to achieve low-latency inter-tile synchronization for multiple applications with independently varying frame-rates. The Two-Phase algorithm is more generally applicable to various high-resolution tiled display systems. The One-Phase algorithm provides superior results but requires the support for NTP, and is more CPU-intensive.

Frame synchronization is an important functionality that should be supported in the design of an LTE baseband receiver. Detecting the start of a frame is regularly repeated during transmission and to identify the cells of the network. Typically, the synchronization is performed using correlationbased methods that incur a large number of multiplications and thus increase the power consumption and hardware complexity. Approaches to reduce the rate of multiplications come at the expense of reduced performance of the algorithm. In this paper, we present a multiplication-free synchronization algorithm that is based on K-means clustering and distributed arithmetic and uses the primary synchronization signal (PSS). We also show through simulations that the immense improvement in power consumption and hardware complexity does not entail a degradation in performance compared to current synchronization techniques.

A Channel estimation technique has been proposed with the least square (LS) based on comb-type pilots for orthogonal frequency division multiplexing (OFDM). An interpolator should be used to obtain the channel information between adjacent pilots for a comb-type pattern. However, an interpolation method causes additional errors due to the interpolation properties of not detecting long delayed paths and generating fictitious paths. OFDM has its strength in realistic possibility of constructing the single frequency network (SFN). However, synchronization and channel estimation errors are revealed by multi-path fading with long delayed paths in SFN channels. We propose a robust channel estimator overcoming the adverse effects of long delayed signals in SFNs. A new channel estimator is proposed with the interpolated LS by applying phase shifted samples in the frequency-domain. In particular, the proposed channel estimator is more robust to the single frequency network (SFN) whenever the delay spread is less than the cyclic prefix length. For a Rayleigh channel, the proposed estimator has an almost 3 dB gain comparing to conventional estimator. 1

Progresiones de aprendizaje o propósitos de formación: a. Lograr que el alumno desarrolle una concientización de la importancia de respetar, cuidar y defender a los animales, específicamente los perros que están en la calle sin un hogar, y cuidados. b. Identificar y analizar el impacto, social y sanitario que representan la sobrepoblación de perritos callejeros. c. Implementar y promover los siguientes valores: Responsabilidad: Promover la conciencia sobre la importancia de ser dueños responsables, asegurando el bienestar de los animales bajo su cuidado y evitando el abandono. Compasión: Fomentar la empatía y el cuidado hacia los animales en situación de vulnerabilidad, destacando la importancia de actuar con sensibilidad y preocupación por su bienestar.

This contribution describes design methodology and implementation of a single-chip timing and carrier synchronizer and channel decoder for digital video broadcasting over satellite (DVB-S). The device consists of an A /D converter with AGC, timing and carrier synchronizer with matched filter, Viterbi decoder including node synchronization, byte and frame synchronizer, convolutional de-interleaver, Reed Solomon decoder, and a descrambler.

The abundance of radio signals and their increasing number creates interferences on adjacent signals and sometimes, with co-channel communication. Jammers, which are operated by hackers or by military forces, are another source of smart and powerful interferences. This paper will discuss the effect of the continuous wave interference (CWI) on a radio communication receiver, specifically with the Digital Video Broadcasting for Satellite Second Generation (DVB-S2) communication standard. It investigates the general effect of the interference on a Quadrature Phase Shift Keying (QPSK) signal over each part of the DVB-S2 receiver. It also focuses on the impact of the center frequency and power of the interference on the critical blocks of a DVB-S2 receiver. This study also tries to determine the deviation from the normal operation in the format of mathematical expressions and simulation results. Based on the obtained results, there is a vulnerability in the chain of the receiver's blocks that allows a smart jammer to affect the device with low power interference. The notch filter is utilized as a solution to mitigate the interference. In addition, the effects of this technique on the system's performance are studied. The simulation results show that there is a great improvement after CWI removal according to the Jamming to Signal Ratio (JSR), the Signal-to-Noise Ratio (SNR), and the Bit Error Rate (BER). In some cases, the JSR was reduced by 15 dB, the SNR was improved by 10 dB and BER also improved by 7 dB. However, the notch filter deletes some information from the original signal. This study introduces new ways to clarify the tradeoff between the amount of interference power reduction and removed bandwidth from the signal with notch filtering.

The abundance of radio signals and their increasing number creates interferences on adjacent signals and sometimes, with co-channel communication. Jammers, which are operated by hackers or by military forces, are another source of smart and powerful interferences. This paper will discuss the effect of the continuous wave interference (CWI) on a radio communication receiver, specifically with the Digital Video Broadcasting for Satellite Second Generation (DVB-S2) communication standard. It investigates the general effect of the interference on a Quadrature Phase Shift Keying (QPSK) signal over each part of the DVB-S2 receiver. It also focuses on the impact of the center frequency and power of the interference on the critical blocks of a DVB-S2 receiver. This study also tries to determine the deviation from the normal operation in the format of mathematical expressions and simulation results. Based on the obtained results, there is a vulnerability in the chain of the receiver’s blocks...