scholarly journals High Precision Timing with Parabolic Equation Fitting in Narrowband Systems

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4164
Author(s):  
Zou ◽  
Xu
Keyword(s):  
Parabolic Equation ◽  
High Precision ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Sampling Rate ◽  
Wireless Communication Systems ◽  
Fitting Method ◽  
Fitting In ◽  
Timing Requirement ◽  
Synchronization Performance

Timing forms the basis of wireless communication systems. Orthogonal frequency division multiplexing (OFDM) technology has strict requirements for synchronization performance, and timing errors lead to interference between subcarriers and symbols. Although cyclic prefix (CP) can relax the timing requirement, high precision timing is still necessary and can release the pressure on CP. Due to the uncertainty of signal arrival, there is a sampling offset between the sampling sample’s timing and the real timing, which can be large in the narrowband system with a low sampling rate. In this paper, we propose a parabolic equation fitting method to improve the timing precision in narrowband systems that have two times the rate of the Nyquist sampling rate. The proposed timing method is easy to implement, with low additional complexity compared to traditional timing detection and is based on traditional direct correlator output.

scholarly journals Análisis de la técnica UFMC en un canal multitrayecto y usando estimación de canal

2021 ◽  
Vol 9 (17) ◽  
pp. 26-39
Author(s):  
Hugo Wladimir Iza Benítez ◽  
Diego Javier Reinoso Chisaguano
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Filter Bank ◽  
Estimation Method ◽  
Wireless Communication Systems ◽  
Ofdm Systems ◽  
Matlab Simulation ◽  
Fifth Generation ◽  
Power Spectral ◽  
Filter Bank Multicarrier

UFMC (Universal Filtered Multi-Carrier) is a novel multi-carrier transmission technique that aims to replace the OFDM (Orthogonal Frequency Division Multiplexing) modulation technique for fifth generation (5G) wireless communication systems. UFMC, being a generalization of OFDM and FBMC (Filter Bank Multicarrier), combines the advantages of these systems and at the same time avoids their main disadvantages. Using a Matlab simulation, this article presents an analysis of the robustness of UFMC against fading effects of multipath channels without using a CP (cyclic prefix). The behavior of the UFMC system is analyzed in terms of the PSD (Power Spectral Density), BER (Bit Error Rate) and MSE (Mean Square Error). The results show that UFMC reduces the out-band side lobes produced in the PSD of the processed signal. Also, it is shown that the pilot-assisted channel estimation method applied in OFDM systems can also be applied in UFMC systems.

Compressed Edge Spectrum Sensing: Extensions and practical considerations

2019 ◽  
Vol 67 (1) ◽  
pp. 51-59
Author(s):  
Edgar Beck ◽  
Carsten Bockelmann ◽  
Armin Dekorsy
Keyword(s):  
Wireless Communication ◽  
Spectrum Sensing ◽  
Industry 4.0 ◽  
Communication Systems ◽  
Sampling Rate ◽  
Wireless Communication Systems ◽  
Active Systems ◽  
Radio Systems ◽  
Edge Spectrum

Abstract Nowadays, spectrum in industrial radio systems is already overoccupied. Therefore, future Industry 4.0 applications require coexistence management of different wireless communication systems. For identification of active systems, we propose Compressed Edge Spectrum Sensing (CESS). Here, we focus on practical aspects and show that the sampling rate can still be highly reduced.

scholarly journals An auto synchronization technique of unipolar MPAM signals in OFDM and its application for optical wireless communication systems

2015 ◽  
Vol 18 (3) ◽  
pp. 218-224
Author(s):  
Khoa Le Dang ◽  
Phuong Huu Nguyen ◽  
Hiroshi Ochi
Keyword(s):  
Electromagnetic Interference ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Wireless Systems ◽  
Cyclic Prefix ◽  
Wireless Communication Systems ◽  
Optical Wireless Communication ◽  
Frequency Division ◽  
Optical Wireless

Optical wireless systems have attracted attention, because they allow high-speed transmission without electromagnetic interference. Orthogonal frequency division multiplexing (OFDM) can send multiple high speed signals by using orthogonal carrier frequencies. Recently, studies have been focused on the optimal OFDM technique for optical wireless systems. When using OFDM, one important issue is determining the cyclic prefix and removing it from the frame before the receiver detects signals. In this paper, we propose a new auto synchronization technique of unipolar MPAM signals. It can remove the cyclic prefix in any sample of the OFDM frame using unipolar MPAM. It is a candidate for wideband systems and using 2-PAM or 4-PAM. The results of mathematical analysis and simulations show that it can be used for optical wireless systems.

scholarly journals Architecture and Implementation of Fading Compensation for Dynamic Spectrum Access Wireless Communication Systems

VLSI Design ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Masahide Hatanaka ◽  
Toru Homemoto ◽  
Takao Onoye
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Dynamic Spectrum Access ◽  
Dynamic Spectrum ◽  
Wireless Communication Systems ◽  
Clock Frequency ◽  
Spectrum Access ◽  
Ofdm Symbol ◽  
Piecewise Linear Interpolation

This paper proposes an efficient architecture and implementation of fading compensation dedicated to dynamic spectrum access (DSA) wireless communication. Since pilot subcarrier arrangements are adaptively determined in wireless communication systems with DSA, the proposed architecture employs piecewise linear interpolation to the channel response estimation for data subcarriers in order to increase the channel estimation accuracy. The fading compensation for an orthogonal frequency-division multiplexing (OFDM) symbol is performed within the time for one OFDM symbol to make increase of latency smaller. The proposed architecture guarantees real-time processing with 76 MHz or higher clock frequency. The FPGA implementation of the proposed architecture occupies 1,577 slices and works up to 121 MHz.

scholarly journals Analysis of the PAPR Behavior of the OFDM Passband Signal

2019 ◽  
Author(s):  
Frank Andrés Eras ◽  
Italo Alexander Carreño ◽  
Thomás Borja ◽  
Diego Javier Reinoso ◽  
Luis Urquiza-Aguiar ◽  
...  
Keyword(s):  
Bit Error Rate ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Wireless Communication Systems ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm System ◽  
High Power Amplifier

Orthogonal Frequency Division Multiplexing (OFDM) is a technique widely used in today's wireless communication systems due to its ability to combat the effects of multi-path in the signal. However, one of the main limitations of the use of OFDM is its high Peak-to-Average Power Ratio (PAPR), which reduces the efficiency of the OFDM system. The effects of PAPR can produce both out-of-band and in-band radiation, which degrades the signal by increasing the bit error rate (BER), this occurs in both baseband and bandpass sginals. In this document the effect of the PAPR in a OFDM passband signal is analyzed considering the implementation of a High Power Amplifier (HPA) and the Simple Amplitude Predistortion-Orthogonal Pilot Sequences (OPS-SAP) scheme to reduce the PAPR.

scholarly journals Design of an Adaptive Predistorter for Solid State Power Amplifier in Wireless OFDM Systems

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Rui J. P. de Figueiredo ◽  
Lin Fang ◽  
Byung Moo Lee
Keyword(s):  
Performance Improvement ◽  
Power Amplifier ◽  
Communication Systems ◽  
Power Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Wireless Communication Systems ◽  
Ofdm Systems ◽  
High Power Amplifier ◽  
Ofdm Signals

Orthogonal frequency division multiplexing (OFDM) is a powerful modulation choice for wideband wireless communication systems. However, its high peak-to-average power ratio greatly limits the high power amplifier (HPA) power efficiency. Here, we present the design of an adaptive predistorter to compensate the distortion caused by the HPA. Specifically, we deal with the implementation issue of the proposed predistorter in Lee and de Figueiredo's work (2006). The performance improvement by predistorter is verified by both floating-point simulation and fixed-point simulation, where the latter includes the distortion effects from the hardware. The bit widths for OFDM signals, ADC, and DAC are evaluated, and the bit width of 10 is shown to be sufficient for the hardware design.

scholarly journals Analytical bound for the CCDF of Crest Factor in NC-OFDM Systems

2017 ◽  
Vol 11 (4) ◽  
pp. 180
Author(s):  
Mohammed Y. Bendimerad ◽  
Fatima Debbat ◽  
Fethi T. Bendimerad
Keyword(s):  
Fading Channels ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Value Theory ◽  
Design Parameters ◽  
Wireless Communication Systems ◽  
Ofdm Systems ◽  
Crest Factor ◽  
Large Peak

Non-contiguous orthogonal frequency division multiplexing (NC-OFDM) is a promising framework for wireless communication systems due to OFDM characteristics like the spectral bandwidth efficiency, robustness to frequency selective fading channels, etc. However, it has been widely known that multicarrier signals generated by OFDM technique exhibit a large peak to average power ration (PAPR), one of the main impediment that has limited the applicability of OFDM systems. Several approaches are employed in literature to derive the PAPR distribution and thus try to reduce it in OFDM context, as Central limit theorem and modern extreme value theory. In new contexts like NC-OFDM systems when flexible access to spectrum is done with non-contiguous portions, the PAPR distribution remains generally unknown, and it is necessary to describe it, since this is one of the key design parameters. In this correspondence, we develop the PAPR bound expression in NC-OFDM context.

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