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In this paper, we present the baseband receiver design for IEEE 802.11ah. We study several key receiver algorithms, including coarse frequency offset estimation and coarse timing synchronization, fine frequency offset estimation, fine timing synchronization, channel estimation and MIMO equalization. For channel estimation, we propose to use decoded SIG field to improve its estimation. To further improve...
The carrier frequency offset(CFO) in OFDM system is one of the key factors that affect the performance of wireless communication. Based on the analysis of the CFO estimation algorithm, this paper presents FPGA implementation scheme in the problem of OFDM fractional CFO estimation using pilot-based algorithm, including CFO estimation and CFO compensation. The circuit modules in the program were written...
Generalized frequency division multiplexing (GFDM) with the flexible structure is one of the promising candidates for the fifth generation wireless communication system. This paper focuses on training sequence design that is used in the estimation of in-phase(I) and quadrature(Q) imbalance parameters on GFDM receivers as well as frequency selective channel. Combining with the structure of low complexity...
This paper analyzes the effect of bubble noise and Doppler shift in an underwater acoustic communication in addition to the influences by ambient noise and severe multipath propagation. Here Bubbles are assumed to be formed due to breaking of waves under strong winds. The bubble layer thus formed alters the speed of the sound in the field. The changed speed of the sound in the field, results in transmission...
It is indispensable to take a low complexity and high accuracy channel estimation algorithm into account under rapidly growth in wireless communication. In this paper, we propose an algorithm for channel estimation using complementary sequence (CS). By utilizing the fantastic autocorrelation property of CS, time domain channel estimation can be easily achieved. We analyzed the complementary sequence,...
The cognitive radio (CR) have been proposed to improve spectral efficiency and to meet growing demands for higher data rates in mobile communications and satellite communications. In this paper, we propose a blind estimation algorithm for a secondary user to estimate transmission parameters of the primary signal in an OFDM overlay system, using only the available fast Fourier transform (FFT) component...
One of the orthogonal frequency division multiplexing (OFDM) schemes is the Time Domain Synchronous OFDM (TDS-OFDM) scheme, in which, the guard intervals between consecutive OFDM symbols contain Pseudo Noise (PN) sequences which are known to the receiver and are used for channel estimation and synchronization. In this paper, a joint channel estimation algorithm is proposed for TDS-OFDM scheme, the...
A novel method for distance estimation is introduced, based on an OFDM signal combined with the Zadoff-Chu Sequences. By exploiting the properties of these sequences it is possible to evaluate the distance between a transmitter and a receiver with a very good precision and accuracy. The technique effectiveness is demonstrated in a real operating environment by measuring the distance between two active...
In this paper, we propose a tracking mechanism for the residual sampling clocking offset (SCO) with corresponding pilot and auxiliary pilot arrangements for filter bank multi-carrier (FBMC) offset QAM (OQAM) baseband receiver in the 60 GHz band. This work can effectively compensate the non-ideal effects on the high-band subcarriers while using more data subcarrier for increasing bandwidth efficiency...
This work addresses the problems of frequency synchronization and channel estimation for OFDM/OQAM systems in Rayleigh fading channel. A two-step preamble based approach using a new frame structure is proposed. The first step is coarse carrier frequency offset (CFO) estimation and the second step is joint fine CFO (FCFO) and channel estimation. We also propose a FCFO estimator under the assumption...
In this paper, we analyze Mean Square Error performances of the frequency offset estimator based on the Moose algorithm. From the analytical result, we indicate a possibility of the iteratively offset estimator and propose a modified estimator structure. By computer simulations, we evaluate the proposed iterative offset estimator and a compatibility with the theoretical analysis.
In this paper, we address the problems of frequency and timing synchronization for OFDM/OQAM systems in additive white Gaussian noise (AWGN) channel. A two step preamble based approach for carrier frequency offset (CFO) and timing offset (TO) estimation is proposed. The first step is joint coarse CFO and TO estimation and the second step is fine CFO (FCFO) estimation. We derive the Cramer-Rao lower...
In an effort to augment existing bit-level network security mechanisms, a significant amount of research has been conducted in the area of physical layer device discrimination. One such physical layer device discrimination technique, known as RF-DNA fingerprinting, has successfully demonstrated serial number device discrimination. This work extends the RF-DNA fingerprinting state-of-the-art by investigating...
Orthogonal Frequency Division Multiplexing (OFDM) signals suffer from high PAPR (Peak to Average Power Ratio). Cyclic shifted sequences (CSS) was proposed as a solution to high PAPR. CSS reduces PAPR stochastically by giving some independent cyclic shifts to the time-domain signals of clusters. In CSS, however, we must transmit side information (SI) regarding the cyclic shift. Although a blind method...
One of the most promising ways of bringing localization services to GPS denied areas is the use of wireless sensor networks. For time difference of arrival (TDOA) systems, the achievable accuracy highly depends on the synchronization accuracy between the sensor nodes. In this paper we describe a new algorithm that achieves an ultra-precise wireless frequency synchronization using OFDM signals. Especially...
MIMO-OFDM is commonly used for communication system because it provides high data rates and fading effect which is introduced by multipath propagation; the system is robust against it. In MIMO-OFDM, channel estimation is a crucial technique for the estimation of the transmitted signal bits upon the received signal bits. Designing pilot pattern is an important step to realize PSA-OFDM. For channel...
The paper introduces a novel method for distance estimation based on an OFDM signal combined with the Zadoff-Chu sequences. By exploiting the properties of these sequences, it is possible to evaluate the distance between two active nodes with a very good precision and accuracy. The technique effectiveness is demonstrated by measuring the distance between a single transmitter and a synchronized receiver...
Mobile Communication systems are affected apparently by the Doppler Frequency and Doppler Rate. In multicarrier systems, because of sensitiveness to frequency offset, estimation and compensation are of great importance, which determine system performance directly. In this paper, we consider this problem in FBMC-OQAM system, and based on the property of it, a proper structure of preamble sequence,...
The single-carrier frequency-division multiple access (SC-FDMA) or the discrete Fourier transform (DFT) pre-coded orthogonal frequency-division multiple access (OFDMA) technique has been adopted in the uplink transmission of the long term evolution (LTE) terrestrial communication standard, for its lower peak-to-average power ratio (PAPR) and similar receiver complexity, compared with OFDM. It is,...
The Data Over Cable Service Interface Specification (DOCSIS) provides internet access via cable TV networks. The latest version 3.1 replaces the Physical Layer of previous DOCSIS versions. With DOCSIS 3.1, broadband cable network operators want to accelerate their networks to gigabit-per-second speeds. Enhancements include an increased bandwidth per downstream channel of up to 192MHz, Orthogonal Frequency-Division...
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