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This paper describes an automatic gain control (AGC) scheme for a bursty wireless communication system designed for point-to-multipoint links. The architecture and operation of the AGC is described. The characterization process of the AGC system is detailed and the entire AGC system is simulated in Matlab to study its transient and steady state behavior in overdriven and underdriven conditions. It...
A novel blind time-frequency joint synchronization based on the cyclostationary of orthogonal frequency division multiplexing with offset quadrature amplitude modulation (OFDM/OQAM) systems is conceived in multipath channels conditions. The cyclic cumulants of OFDM/OQAM signals are derived firstly, symbol timing offset (STO) and carrier frequency offset (CFO) are estimated by employing two groups...
Multi-channel speech enhancement algorithms rely on a synchronous sampling of the microphone signals. This, however, cannot always be guaranteed, especially if the sensors are distributed in an environment. To avoid performance degradation the sampling rate offset needs to be estimated and compensated for. In this contribution we extend the recently proposed coherence drift based method in two important...
We present an optimal frame timing estimator for OFDM signals that utilizes both cyclic prefix (CP) and pilot-carrier-aided channel estimation. Combining the periodic nature of the embedded pilot signal information with the correlation present in the cyclic prefix allows improved frame timing estimates relative to use of either one. Following a derivation of the ML estimator, a processor diagram is...
This work studies a digital transmission system by fiber optic. We give special relevance to the synchronism block. The fiber is a transmission medium with large bandwidth and low attenuation. These characteristics allow high speed and long distances. The transmission, instead asynchronous, it is synchronous what provides a big efficiency of 100%. However, the synchronous transmission needs a synchronizer...
The latest extended-coverage (EC-GSM-IoT) and high-throughput (EGPRS2A) enhancements make GSM competitive to LTE-based cIoT standards such as NB-IoT with the advantage of global coverage today. This work introduces the first fully-integrated RF-SoC supporting the complete GSM standard family ranging from EC-GSM-IoT through EGPRS2A. The RF-SoC achieves −121.7 dBm receiver sensitivity and peak data...
The paper outlines methods that employ the properties of popular FSK (Frequency-shift Keying) modulation for covert transmission of data between two radio transceivers. With the use of dedicated modulation, the risk of interception of confidential information on military radio channels is considerably reduced. The paper also discusses the methods of radio signal modulation in practical applications,...
An electric network frequency (ENF) signal can be found in multimedia recordings due to propagation from the power grid. There a variety of applications based on ENF signal use, such as video and audio stream synchronization, and origin determination of multimedia recordings. In this paper, we propose the use of ENF to synchronize real-time audio streams from different, non-synchronized sound devices,...
A joint timing offset (TO) and frequency offset (FO) estimation method based on Radon-Wigner transform (RWT) is first proposed for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems. The result shows that the timing and frequency synchronization performance of the proposed method are both better than the Schmidl & Cox method and fractional Fourier transform (FrFT) algorithm...
Low power wide area network (LPWAN) receivers must first decide about the presence of a transmission in order to retrieve the information that was being sent by wireless sensor nodes. This is exacerbated by the use of modern coding techniques that are able operate at very low signal to noise ratio (SNR), and inaccuracies originating from the transmitter hardware. Several, mostly low complexity methods...
This paper studies a system where a set of relay nodes harvest energy from the signal received from a source to later utilize it when forwarding the source's data to a destination node via distributed beamforming. To this end, we derive (approximate) analytical expressions for the mean SNR at destination node when relays employ: i) time-switching based energy harvesting policy, ii) power- splitting...
In interactive satellite communication systems, adaptive coding and modulation is a suitable countermeasure to mitigate the high fade dynamics of frequency ranges like the Ka-band. Consequently, receivers that support operation at low and very low SNR are required. In this paper, we present such a receiver structure dedicated for burst reception in a MF-TDMA system, as it is typically adopted in the...
In 2012, IEEE Std 802.15.6 was defined for short-range, wireless communications in the vicinity of, or inside, a human body. This paper mainly proposes a novel synchronization algorithm for the IR-UWB receiver targeting IEEE 802.15.6 Standard according to the characteristics of Kasami sequence in the UWB synchronization header. One Kasami sequence can be chosen as the template which is multiplied...
Orthogonal frequency division multiplexing (OFDM) is one important technologies of power line communication (PLC). This paper presents a new timing synchronization method for OFDM system which can be used in PLC. The proposed timing method is performed by calculating the correlation between the received signal and a local training sequence which is the same as the training sequence of OFDM signal...
Simultaneous collection of electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) is a promising neuroimaging technique, which can provide high resolution in both spatial and temporal domain. Because EEG recorded in MRI scanners is heavily contaminated with gradient artefact (GA), removal of GA from EEG is a crucial step in EEG-fMRI data analysis. To date, the most efficient methods...
The paper presents an efficient parallel carrier synchronization algorithm suitable for high speed demodulator system and easy to implement on FPGA platform. The parallel algorithm combines the phase frequency detector (PFD) algorithm of the fast capture and the phase detector (PD) algorithm of the stable tracking. First, it can quickly capture carrier frequency offset by using PFD algorithm. Then,...
Analog-to-digital (A/D) conversion plays a crucial role when it comes to the design of energy-efficient and fast signal processing systems. As its complexity grows exponentially with the number of output bits, significant savings are possible when resorting to a minimum resolution of a single bit. However, then the nonlinear effect which is introduced by the A/D converter results in a pronounced performance...
Recentry, interference of artificial noises from electrical power transfer becomes large and deterioration of sound quality of AM radio is worried. The authors proposed a noise suppression system for AM radio using quadrature demodulation and PI algorithm. It is expected that the noise suppression effect is reduced when the system has a synchronization error. In this paper, an effect of synchronization...
In this paper, the authors address the problem of true Cramer-Rao lower bound (CRLB) derivation for a non-data-aided (NDA) vector parameter estimation over non-constant gain flat Rayleigh fading channel (FRFC). General CRLB expressions for carrier frequency offset, carrier phase, symbol timing and signal to noise ratio (SNR) estimation are analytically developed going through the computation of the...
The abundant spectrum at millimeter-wave (mmWave) has the potential to greatly increase the capacity of 5G cellular systems. However, to overcome the high pathloss in the mmWave frequencies, beamforming with large antenna arrays is required at both the base station and user equipments for sufficient link budget. This feature is a challenge for beamforming training during initial access due to low...
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