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About 3,472 papers for “Frame synchronization”

Optimal Sequential Frame Synchronization

Venkat Chandrasekaran, Aslan Tchamkerten, Gregory Wornell · 2007

We consider the ‘one-shot frame synchronization problem ’ where a decoder wants to locate a sync pattern at the output of a channel on the basis of sequential observations. We assume that the sync pattern of length N starts being emitted at a random time within some interval of size A, that characterizes the asynchronism level between the transmitter and the receiver. We show that a sequential decoder can optimally locate the sync pattern, i.e., exactly, without delay, and with probability approaching one as N → ∞, if and only if the asynchronism level grows as O(e Nα), with α below the synchronization threshold, a constant that admits a simple expression depending on the channel. This constant is the same as the one that characterizes the limit for reliable asynchronous communication, as was recently reported by the authors. If α exceeds the synchronization threshold, any decoder, sequential or non-sequential, locates the sync pattern with an error that tends to one as N → ∞. Hence, a sequential decoder can locate a sync pattern as well as the (non-sequential) maximum likelihood decoder that operates on the basis of output sequences of maximum length A + N − 1, but with much fewer observations.

Cited by 0

Active Seismic frame synchronization

Lanning, H. E. · USRA Houston Repository (Lunar and Planetary Institute) · 2015

This ATM determines the probability of sync, false sync, and the probability of loosing sync for an 11 bit and 6 bit frame sync code. The number of bits/frame range from 1344 to 4032. The amount of data lost during loss of sync is also determined.

Cited by 0

On Iterative Frame Synchronization

A. Abdel-Samad · 2006

Iterative receiver techniques provide a powerful tool to enhance receiver performance and are gradually becoming the norm in modern communication systems. In this paper, we investigate the impact of using iterative frame synchronization in a coded packet communication system in terms of false acquisition probability (FAP), mean squared channel estimation error (MSCEE), un-coded bit error rate (BER) and block error rate (BLER) under additive white Gaussian noise (AWGN) and frequency-selective channels. Our simulations show substantial FAP and MSCEE gains and moderate BER and BLER gains. We also propose a new low-complexity optimized inner iteration technique that offers performance gains close to those achieved by the more demanding outer iterations

Cited by 0

Frame synchronization based on multiple frame observations

Eesa Bastaki, Harry H. Tan, Yi Shi et al. · IEEE Transactions on Wireless Communications · 2010

We consider frame synchronization for fixed frame length communication system with periodically embedded sync words. In the past few decades, numerous researchers have made significant contributions in various aspects. However, it is almost surprising that a scrutinization over the literature reveals to us an important common assumption: frame synchronization decision-making through single-frame observation. Intuition tells us that an enlarged multiple-frame observation set bears the potential to reduce sync word identification ambiguities and also to combat multi-path fading through ¿frame diversity¿. The objective of this work is thus to characterize the performance improvement of using multiple-frame decision rules rather than the single-frame decision rules considered in the previous work. We select the work of Lui and Tan as our standing point, and have conducted a comparative study in a very comprehensive manner. In particular, we shall show that the benefits of multipleframe based decision rules can be substantial. For example, in many cases, the performance of the correlation rule based on double-frame observation is superior to that of the optimum maximum likelihood rule with single-frame observation. While further enlarging the observation period beyond double frames was found to yield diminishing returns.

Cited by 19

Frame Synchronization Method for Adaptive Frame Length System

Mingxue Bi, Hongxia Wang · The Open Automation and Control Systems Journal · 2014

Aiming at the difficult for identifying the alterable length frames, a specific method of frame synchronization is proposed to solve the problem of frame synchronization for the adaptive frame length system. In the novel method, the core innovation about new frame format has been done. Based on the new frame format, the alterable length frames are demarcated by searching Frame Synchronization Header bit by bit and checking Frame Synchronization Header frame by frame. Then the relevant performance parameters are analyzed and educed. Finally, a simulation system is designed to verify the proposed method. By simulating, the reference values for the rear protect time and the ahead protect time are given to ensure the probability of frame synchronization method. The significance of solving the problem is to ensure the reliability of data transmission and processing for the adaptive frame length system. Compared with previous work, the novel method can enter the frame synchronization more easily.

Cited by 0Open access

Frame synchronization in OFDM systems

Gürsan, Hakan Yesari · OpenMETU (Middle East Technical University) · 2019

In this thesis, we considered the problem of frame synchronization and channel estimation in Orthogonal Frequency Division Multiplexing (OFDM) systems. Since framing error may cause severe ISI and may disturb the orthogonality of the subcarriers, frame synchronization must be accomplished at the OFDM receiver. Furthermore, the effects of channel must be compensated to obtain the symbols accurately. We investigated several frame synchronization algorithms including a maximum likelihood (ML) synchronizer which relies on the periodicity induced in the OFDM structure, and a robust synchronizer which uses a special training symbol. These algorithms are evaluated in AWGN and Rayleigh fading multipath channels and performances are compared in terms of percentage of ISI-free synchronization, mean squared error and symbol error rate. The IEEE 802.11a framework is used to compare these algorithms with the standard system which utilizes training symbols dedicated for synchronization. It is shown that an adjustment for the frame start estimates must be done to avoid the effects of the channel delay spread. It is also pointed that ideal synchronization is not necessary unless symbol boundaries are detected inside an ISI-free region and the error aroused in ISI-free synchronization can be compensated by applying channel estimation and equalization regarding the same symbol boundaries.

Cited by 0Open access

Frame synchronization performance and analysis

Pitt, G. H., III, Swanson, L., Aguilera, C. S. R. · NASA STI Repository (National Aeronautics and Space Administration)

The analysis used to generate the theoretical models showing the performance of the frame synchronizer is described for various frame lengths and marker lengths at various signal to noise ratios and bit error tolerances.

Cited by 0Open access

Compressed ELM-Based Frame Synchronization

Chaojin Qing, Qian Zhao, Na Yang et al. · IEEE Transactions on Vehicular Technology · 2024

The extreme learning machine (ELM)-based frame synchronization (FS) improves the correctness of classical FS methods to a certain extent. However, it still faces challenges associated with the high complexity of the hidden layer and the difficulty in identifying the first-arriving resolvable path. To tackle the issue of high complexity, this paper leverages the compressibility of FS metrics to construct a compressed ELM network, drawing inspiration from the compression and reconstruction mechanism of compressed sensing (CS). To alleviate the challenge of identifying the first-arriving path in ELM-based FS, a detection threshold is designed to perform a backward search in the output of ELM. Simulation results indicate that the proposed method significantly improves the FS error probability and demonstrates the robustness to parameter variations.

Cited by 4

Variance based OFDM frame synchronization

Zbynek Fedra, Bojan Dimitrijević, Nenad Milošević et al. · Brno University of Technology Digital Library (Brno University of Technology) · 2012

The paper deals with a new frame synchronization scheme for OFDM systems and calculates the complexity of this scheme. The scheme is based on the computing of the detection window variance. The variance is computed in two delayed times, so a modified Early-Late loop is used for the frame position detection. The proposed algorithm deals with different variants of OFDM parameters including guard interval, cyclic prefix, and has good properties regarding the choice of the algorithm's parameters since the parameters may be chosen within a wide range without having a high influence on system performance. The verification of the proposed algorithm functionality has been performed on a development environment using universal software radio peripheral (USRP) hardware.

Cited by 2Open access

OFDM frame synchronization for dispersive channels

Daniel Landström, Nils F Petersson, Per Ödling et al. · 2002

We address time synchronization in an OFDM system and present an ML estimator that also is unbiased for dispersive channels. The estimator uses the redundancy introduced by the cyclic prefix and knowledge of the channel. Previously presented estimators based on the cyclic prefix are either biased or have high complexity for this environment. We show that with proper choice of signal model, the complexity can be reduced considerably while maintaining the performance. Part of the novelty lies in the proper decomposition of correlation matrices that appear in the ML estimator. The new estimator structure consists of a linear filter, followed by an auto-correlating filterbank and a maximization.

Cited by 8

Frame Synchronization for a Single Packet

Stephan Pfletschinger · 2025

We derive the optimum method for locating a single packet in a received frame of symbols, using not only the samples that correspond to a known preamble but those of the entire transmitted packet. This approach leads to significant improvements compared to detection methods based on the preamble alone. For BSPK and on-off keying and their combinations with Manchester coding, we present simplified maximum likelihood metrics which are near-optimum while their computational complexity is only slightly higher than a simple correlation. Finally, we show how this metric can be derived for other modulations with memory.

Cited by 0Open access

On frame synchronization in aeronautical telemetry

Michael Rice, Andrew McMurdie · IEEE Transactions on Aerospace and Electronic Systems · 2016

Frame synchronizers, suitable for use with continuous phase modulation (CPM) in the presence of phase and frequency offsets, are derived for periodically inserted preamble bits in continuous-mode transmission. The resulting frame synchronizers involve single or double correlations of the received samples with a local copy of the CPM samples corresponding to the preamble bits. Of particular interest in aeronautical telemetry is shaped offset QPSK, telemetry group version (SOQPSK-TG), with the preamble defined in the integrated network enhanced telemetry (iNET) standard. Two low-complexity versions that leverage the special properties of the iNET preamble and SOQPSK-TG operating at 2 samples/bit are developed. Simulation results show that most frame synchronizers are capable of achieving acceptable performance for E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ≥ 0 dB and the maximum frequency offset that can be tolerated increases with E <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">b</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> to about 3%of the bit rate.

Cited by 10

Efficient Multiplierless Architecture for Frame Synchronization

Emmanuel Boutillon, Pansoo Kim, Christian Rol et al. · 2011

Abstract—The most challenging step of the demodulation of the DVB-S2 signal with function of VCM (Variable Coding and Modulation)/ACM (Adaptive Coding and Modulation) is the detection of the PL (Physical Layer) header. PL header is transmitted using pi/2-BPSK modulation and is composed of a fixed part (26 bits of Start Of Frame (SOF)) and a variable part (64 bits codeword of PL Signaling (PLS) code that defines the structure of the PL frame). Since the 90 bits corresponding to the PL header are affected by noise, the carrier frequency offset and the phase noise, the synchronization task in a DVB-S2 receiver is thus a critical task. In this paper, we present a properties of the Hadamard code used to encode the information of the PLS code to reinforce frame detection before knowing the actual value of the MODCOD/TYPE. Moreover, we propose to perform the computation in the polar domain in order to avoid the need of multiplier and thus, to obtain a very low cost implementation. The associated decoder architecture is presented together with the measured performance at the worst case SNR (i.e-3 dB). I.

Cited by 0

Inter-Symbol Interference Aware Frame Synchronization

Roberto Pedone, M. Villanti, Giovanni Emanuele Corazza · 2006

Frame synchronization is conventionally intended as "epoch recovery" of a symbols synchronous stream. But, what happens when symbol timing is unknown? A typical approach to this problem involves oversampling, which is computational intensive. This paper introduces a novel alternative approach whereby the detector is made aware of the emerging ISI due to imperfect symbol timing recovery in order to achieve the wanted performance with low computational complexity. The resulting sequence, identified as ISI-UW, is obtained as the combination of several conventional UW appropriately shifted in time. The adoption of this particular sequence structure allows to enhance performance in the worst case scenario, at the cost of a slight performance loss in the ideal case, and reveals to be an interesting low-complexity alternative to conventional oversampling techniques to cope with symbol timing fractional misalignments

Cited by 0

Optimal Frame Synchronization Under General Arrivals

Meenakshi Sundaram Ramamoorthy, Devendra Jalihal, Venkatesh Ramaiyan · IEEE Transactions on Communications · 2018

We study the problem of frame synchronization over a discrete memoryless channel (DMC) in an asynchronous setup. A sync frame is transmitted at a random time V with a known distribution {α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</sub> } and entropy H. We seek to characterize the minimum average length or energy of the sync frame necessary for error-free frame synchronization, as H tends to infinity. We present a variable length sync frame, where the length of the sync frame is adapted based on H and {α <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</sub> }, for the general arrival distribution and show error-free frame synchronization when the average sync frame length Ñ scales as Ω((H/α(Q)), where α(Q) is the synchronization threshold of the DMC. We then generalize the framework and study a tradeoff between Ñ and α(Q) for optimal frame synchronization and characterize the scaling needed of both Ñ and α(Q) with H. We illustrate our results with the AWGN channel and discuss the adapting sync frame length and symbol power for optimal frame synchronization. Finally, using numerical work and simulations, we evaluate the results under relaxed assumptions, including the imperfect knowledge of arrival distribution and symbol timing error.

Cited by 2