scholarly journals HRR Profiling on Integrated Radar-Communication Systems Using OFDM-PCSF Signals

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Xuanxuan Tian ◽  
Tingting Zhang ◽  
Qinyu Zhang ◽  
Zhaohui Song
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Waveform Design ◽  
Data Rate ◽  
Frequency Division ◽  
Range Resolution ◽  
High Data ◽  
Range Profile ◽  
Transmission Data ◽  
Stepped Frequency

In order to improve both the transmission data rate and the range resolution simultaneously in integrated radar-communication (RadCom) systems, orthogonal frequency-division multiplexing with phase-coded and stepped-frequency (OFDM-PCSF) waveform is proposed. A corresponding high resolution range (HRR) profile generation method is also presented. We first perform OFDM-PCSF waveform design by combining the intrapulse phase coding with the interpulse stepped-frequency modulation. We then give the ambiguity function (AF) based on the presented waveforms. Then, the synthetic range profile (SRP) processing to achieve HRR performance is analyzed. Theoretical analysis and simulation results show that the proposed methods can achieve HRR profiles of the targets and high data rate transmissions, while a relative low computational complexity can be achieved.

scholarly journals Channel estimation of OFDM in C-band communication systems under different distribution conditions

2021 ◽  
Vol 23 (3) ◽  
pp. 1778
Author(s):  
Heba Abdul-Jaleel Al-Asady ◽  
Hassan Falah Fakhruldeen ◽  
Mustafa Qahtan Alsudani
Keyword(s):  
Fourier Transform ◽  
Channel Estimation ◽  
Fast Fourier Transform ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
High Data ◽  
High Efficient

<p>Orthogonal frequency division multiplexing (OFDM) is a transmission system that uses multiple orthogonal carriers that are sent out at the same time. OFDM is a technique for mobile and wireless communication that has high-efficient frequency utilization, high data-rate transmission, simple and efficient implementation using the fast Fourier transform (FFT) and the inverse fast Fourier transform (IFFT), and reduces inter symbol interference (ISI) by inserting cyclic prefix (CP). One of the most important approaches in an OFDM system is channel estimation. In this paper, the orthogonal frequency division multiplexing system with the Rayleigh channel module is analyzed for different areas. The proposed approach used large numbers of subcarriers to transmit the signals over 64-QAM modulation with pilot add channel estimation. The accuracy of the OFDM system is shown in the measuring of the relationships of peak power to the noise ratio and bit error rate.</p>

PAPR REDUCTION IN MIMO SC-FDMA- A SURVEY

2015 ◽  
Vol 2 (2) ◽  
Author(s):  
HARSHA PRAKASH ◽  
C.D. SURIYAKALA
Keyword(s):  
Power Amplifier ◽  
Communication Systems ◽  
Multiple Access ◽  
Average Power ◽  
Data Rate ◽  
High Data Rate ◽  
Modulation Method ◽  
Frequency Division ◽  
High Data ◽  
Power Amplifier Efficiency

To meet the requirements of high data rate, third generation partnership project (3GPP) has come across the development of long term evolution (LTE). High data rate can be achieved with the help of an advanced modulation method. Orthogonal Frequency Division Multiple Access (OFDMA) was considered as a modulation method especially in the downlink of the communication systems. It gives many advantages like frequency diversity, increased capacity and robustness against impulse noise. Besides these advantages, a major drawback of OFDMA is its high peak-to-average power ratio (PAPR). High PAPR affects the system by lowering the power amplifier efficiency, increased complexity as well as shorter battery life. In case of uplink communication, where better peak power characteristics benefit the mobile terminals with respect to power efficiency, OFDMA is not a possible solution. To handle such situations, 3GPP has introduced a modified form of OFDMA which is known as Single-Carrier Frequency Division Multiple Access (SC-FDMA). It provides same advantages as OFDMA along with low PAPR. To further improve the bit error rate (BER) performance of the system and power amplifier efficiency Multiple-Input Multiple-Output (MIMO) can be extended to SC-FDMA system. This paper surveys causes, effects and possible solutions of high PAPR in a communication system.

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.

scholarly journals Capacity Enhancement in WLAN using MIMO

2011 ◽  
pp. 101-106
Author(s):  
K. Shamganth ◽  
M. P. Reena
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Performance ◽  
Multiple Input Multiple Output ◽  
Data Rate ◽  
High Data Rate ◽  
Ieee 802.11A ◽  
High Data ◽  
Standard Design ◽  
Input Multiple Output

Increasing demand for high-performance 4G broadband wireless is enabled by the use of multiple antennas at both transmitter and receiver ends. Multiple antenna technologies enable high capacities suited for Internet and multimedia services, and also dramatically increase range and reliability. The combination of multiple-input multiple-output (MIMO) signal processing with orthogonal frequency division multiplexing (OFDM) is regarded as a promising solution for enhancing the data rates of next-generation wireless communication systems operating in frequencyselective fading environments. In this paper ,we focus mainly on Internet users in hotspots like Airport etc., requiring high data rate services. A high data rate WLAN system design is proposed using MIMO-OFDM. In the proposed WLAN system, IEEE 802.11a standard design is adopted but the results prove a data rate enhancement from the conventional IEEE 802.11a.

scholarly journals EVM Loss: A Loss Function for Training Neural Networks in Communication Systems

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1094
Author(s):  
Scott Stainton ◽  
Martin Johnston ◽  
Satnam Dlay ◽  
Paul Anthony Haigh
Keyword(s):  
Neural Networks ◽  
Loss Function ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Efficiency Gain ◽  
Frequency Division ◽  
Error Vector Magnitude ◽  
Modulation Formats ◽  
Complex Approach

Neural networks and their application in communication systems are receiving growing attention from both academia and industry. The authors note that there is a disconnect between the typical objective functions of these neural networks with regards to the context in which the neural network will eventually be deployed and evaluated. To this end, a new loss function is proposed and shown to increase the performance of neural networks when implemented in a communication system compared to previous methods. It is further shown that a ‘split complex’ approach used by many implementations can be improved via formalisation of the ‘concatenated complex’ approach described herein. Experimental results using the orthogonal frequency division multiplexing (OFDM) and spectrally efficient frequency division multiplexing (SEFDM) modulation formats with varying bandwidth compression factors over a wireless visible light communication (VLC) link validate the efficacy of the proposed method in a real system, achieving the lowest error vector magnitude (EVM), and thus bit error rate (BER), across all experiments, with a 5 dB to 10 dB improvement in the received symbols EVM overall compared to the baseline implementation, with bandwidth compressions down to 40% compared to OFDM, resulting in a spectral efficiency gain of 67%.

Light fidelity optical network a comparative performance evaluation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Devendra Kr. Tripathi ◽  
Pallavi Singh
Keyword(s):  
Communication Systems ◽  
Optical Network ◽  
Visible Light Communication ◽  
Data Rate ◽  
Comparative Performance ◽  
Modulation Formats ◽  
High Data ◽  
Modulation Format ◽  
Output Performance ◽  
High Spectral Efficiency

Abstract Light-Fidelity (Li-Fi) is the bidirectional communication technique, tenders almost unlimited bandwidth, exploit unlicensed spectrum of light waves. Accordingly, this manuscript illustrates usage of visible light communication (VLC) applied as Li-Fi, an efficient scheme to broadcast data wirelessly as well safer technique in contrary to the customary Wireless-Fidelity (Wi-Fi) networks. In support numerical simulations have been executed over the proposed Li-Fi model for the parametric variation with the data rate, laser power, modulation format and wavelength, communication length. Investigations have showed good output performance, with hike in data rate BER variation as 10−94–10−23 and testing length. Simulations of network with DPSK and NRZ modulation formats at high data transmission of 10 Gbps have showed good output performance with 10−40 with DPSK format. Li-Fi systems are quality solution for the impending communication systems save cost, provide high spectral efficiency.

QoS-Constrained Resource Allocation Scheduling for LTE Network

2015 ◽  
Vol 4 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Hung-Chin Jang ◽  
Yun-Jun Lee
Keyword(s):  
Resource Allocation ◽  
Data Transmission ◽  
Orthogonal Frequency Division Multiplexing ◽  
Transmission Rate ◽  
High Mobility ◽  
System Throughput ◽  
Frequency Division ◽  
High Data ◽  
Single Carrier ◽  
Allocation Method

The goal of LTE (Long Term Evolution) is to provide high data transmission rate, scalable bandwidth, low latency, high-mobility, etc. LTE employs OFDM (Orthogonal Frequency Division Multiplexing) and SC-FDMA (Single Carrier - Frequency Division Multiple Access) for downlink and uplink data transmission, respectively. As to SC-FDMA, there are two constraints in doing resource allocation. First, the allocated resource blocks (RBs) should be contiguous. Second, those of the allocated RBs are forced to use the same modulation technique. The aim of this research is to propose a QoS-constraint resource allocation scheduling to enhance data transmission for uplink SC-FDMA. The proposed scheduling is a three-stage approach. In the first stage, it uses a time domain scheduler to differentiate user equipment (UE) services according to their distinct QoS service requirements. In the second stage, it uses a frequency domain scheduler to prioritize UE services based on channel quality. In the third stage, it limits the number of times of modulation downgrade of RBs allocation in order to enhance system throughput. In the simulations, the proposed method is compared to fixed sub-carrier dynamic resource allocation method and adaptive dynamic sub-carrier resource allocation method. Simulation results show that the proposed method outperforms the other two methods in terms of throughput, transmission delay, packet loss ratio, and RB utilization.

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