scholarly journals Joint Channel Estimation and Synchronization Techniques for Time-Interleaved Block-Windowed Burst OFDM

2021 ◽  
Vol 11 (10) ◽  
pp. 4403
Author(s):  
João Martins ◽  
Filipe Conceição ◽  
Marco Gomes ◽  
Vitor Silva ◽  
Rui Dinis
Keyword(s):  
Channel Estimation ◽  
Communication Systems ◽  
Power Efficiency ◽  
Frame Synchronization ◽  
Frequency Domain Multiplexing ◽  
Training Sequences ◽  
Data Rates ◽  
The One ◽  
Time Interleaved ◽  
Joint Channel

From a conceptual perspective, beyond-5G technologies promise to deliver very low latency, even higher data rates, and ultrareliable connections for future generations of communication systems. Modulation schemes based on orthogonal frequency-domain multiplexing (OFDM) can accommodate these requirements for wireless systems. Several hybrid OFDM-based systems, such as the time-interleaved block-windowed burst–OFDM (TIBWB–OFDM), are capable of achieving even better spectral confinement and power efficiency. This paper addresses the implementation of the TIBWB–OFDM system in more realistic and practical wireless link scenarios by addressing the challenges of proper and reliable channel estimation and frame synchronization. We propose to incorporate a preamble formed by optimal correlation training sequences such as the Zadoff–Chu (ZC) sequences. The added ZC preamble sequence is used to jointly estimate the frame beginning through signal-correlation strategies and a threshold decision device, and acquire channel-state information (CSI) by employing estimators on the basis of the preamble sequence and transmitted data. The employed receiver estimators show that it is possible to detect the TIBWB–OFDM frame beginning and highlight the robustness of the TIBWB–OFDM technique to imperfect channel estimations by showing that it can provide comparatively close BER performance to the one where the CSI is perfectly known.

scholarly journals Optimum Frequency Allocation Mechanism of TV White Spaces by using Interval Graph

2019 ◽  
Vol 9 (1S5) ◽  
pp. 107-111
Keyword(s):  
Communication Systems ◽  
Interval Graph ◽  
Wireless Communication Systems ◽  
Optimum Number ◽  
User Requirements ◽  
Allocation Mechanism ◽  
Optimum Frequency ◽  
Data Rates ◽  
The One ◽  
The Given

The unused frequencies of terrestrial TV are being explored in the recent years, to satisfy the bandwidth demands of ever-increasing wireless communication systems. Allocating these unused TV frequencies is often a challenging task. Allocations that fulfil the user requirements at various instants, while maximizing the utilization of available TV frequencies is the one that is desired. In this paper, interval-graph method is implemented to identify the optimum number of channels needed for the given demand of bandwidths. Simulations are carried out by using GLPK 4.65 solver. Results show the appropriate number of channels required or conversely the reduction of data rates to individual users based on the available bandwidths.

Joint Channel Estimation and Impulsive Noise Mitigation in Underwater Acoustic OFDM Communication Systems

2017 ◽  
Vol 16 (9) ◽  
pp. 6165-6178 ◽  
Author(s):  
Peng Chen ◽  
Yue Rong ◽  
Sven Nordholm ◽  
Zhiqiang He ◽  
Alexander J. Duncan
Keyword(s):  
Channel Estimation ◽  
Communication Systems ◽  
Impulsive Noise ◽  
Noise Mitigation ◽  
Underwater Acoustic ◽  
Joint Channel

scholarly journals A System on a Programmable Chip Architecture for Data-Dependent Superimposed Training Channel Estimation

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Fernando Martín del Campo ◽  
René Cumplido ◽  
Roberto Perez-Andrade ◽  
A. G. Orozco-Lugo
Keyword(s):  
Channel Estimation ◽  
Communication Systems ◽  
Mobile Systems ◽  
Wireless Communication Systems ◽  
Superimposed Training ◽  
Available Bandwidth ◽  
Computational Burden ◽  
Commercial Use ◽  
Training Sequences ◽  
Dependent Sequence

Channel estimation in wireless communication systems is usually accomplished by inserting, along with the information, a series of known symbols, whose analysis is used to define the parameters of the filters that remove the distortion of the data. Nevertheless, a part of the available bandwidth has to be destined to these symbols. Until now, no alternative solution has demonstrated to be fully satisfying for commercial use, but one technique that looks promising is superimposed training (ST). This work describes a hybrid software-hardware FPGA implementation of a recent algorithm that belongs to the ST family, known as Data-dependent Superimposed Training (DDST), which does not need extra bandwidth for its training sequences (TS) as it adds them arithmetically to the data. DDST also adds a third sequence known as data-dependent sequence, that destroys the interference caused by the data over the TS. As DDST's computational burden is too high for the commercial processors used in mobile systems, a System on a Programmable Chip (SOPC) approach is used in order to solve the problem.

scholarly journals Channel Estimation and Peak-to-Average Power Ratio Analysis of Narrowband Internet of Things Uplink Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Md Sadek Ali ◽  
Yu Li ◽  
Md Khalid Hossain Jewel ◽  
Oluwole John Famoriji ◽  
Fujiang Lin
Keyword(s):  
Internet Of Things ◽  
Channel Estimation ◽  
Communication Systems ◽  
Power Efficiency ◽  
Pulse Shaping ◽  
Minimum Mean Square Error ◽  
Average Power ◽  
Estimation Methods ◽  
Area Network ◽  
Power Ratio

Narrowband Internet of Things (NB-IoT) is a cellular based promising low-power wide-area network (LPWN) technology standardized by the 3rd Generation Partnership Project (3GPP) in release-13 as a part of the future 5th Generation (5G) wireless communication systems. The main design target of NB-IoT was to enhance radio coverage by repeating signal over an additional period of time for the ultralow-end IoT devices that would be operated in extreme coverage environments. But the power efficiency of the low-cost NB-IoT user equipment (NB-IoT UE) in the uplink is the major concern. Coverage improvement from signal repetitions depends on the channel estimation quality at extremely bad radio conditions. The typical operating signal-to-noise ratio (SNR) for NB-IoT is expected to be much lower than the zero. In this paper, we have proposed two efficient narrowband demodulation reference signal (NDMRS)-assisted channel estimation algorithms based on the conventional least squares (LS) and minimum mean square error (MMSE) estimation methods. The theoretical analysis and the link-level performance of our proposed estimation methods are presented. Simulation results exhibit that the proposed methods provide better estimation precision compared to the traditional LS and MMSE methods at the low SNR situations. Furthermore, we have analyzed the raised-cosine (RC) and square-root-raised cosine (RRC) pulse shaping to reduce peak-to-average power ratio (PAPR) as an uplink transmit filter. The PAPR values are evaluated through extensive computer simulations for both single-tone and multi-tone transmissions. Our evaluation results vindicate that the RRC pulse shaping with lower PAPR values is feasible to design of practical NB-IoT uplink transmitter and increases power efficiency.

scholarly journals Pilot Placement Schemes for Channel Estimation of Proposed 5G-GFDM System

2019 ◽  
Vol 27 ◽  
pp. 01001
Author(s):  
Suleman Tahir ◽  
Shahzad Amin Sheikh ◽  
Omer Bin Saeed
Keyword(s):  
Channel Estimation ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Next Generation ◽  
High Data ◽  
Pilot Symbols ◽  
Data Rates ◽  
A New Technique

Orthogonal Frequency Division Multiplexing (OFDM) is a highly regarded technique used in the 4G mobile communication systems to provide reliable communication and high data rates due to the orthogonality between its sub carriers. However, it cannot be used in the next generation cellular system i.e. 5G. Thus, a new technique Generalized Frequency Division Multiplexing (GFDM) has been proposed to meet the demands of the next generation systems, which are higher data rates than 4G, minimum response time, lower power consumption etc. GFDM is a non-orthogonal, multicarrier scheme, which seems to fulfil the requirements of the new wireless communication system. The aim of this paper is to use the pilot symbols and their optimum placements within the data for the channel estimation of the GFDM system. It is shown that the optimum arrangement of the pilot symbols is to place them uniformly on equal intervals within the data and to cluster them in the middle of the data.

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