scholarly journals Low-Complexity Progressive MIMO-OFDM Receiver for Underwater Acoustic Communication

Symmetry ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 362 ◽  
Author(s):  
Gang Qiao ◽  
Zeeshan Babar ◽  
Feng Zhou ◽  
Lu Ma ◽  
Xue Li
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Minimum Mean Square Error ◽  
Multiple Input Multiple Output ◽  
Soft Information ◽  
Decision Feedback ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Ldpc Decoding ◽  
Mimo Ofdm

Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) proves to be a better choice for high speed underwater acoustic (UWA) communication as it increases the data rate and solves the bandwidth limitation issue; however, at the same time, it increases the design challenges and complexity of the receivers. Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) are introduced in the received signal by the extended multipath and Doppler shifts along with different types of noises due to the noisy acoustic channel. Here we propose two iterative receivers: one is ICI unaware iterative MIMO-OFDM receiver, which uses a novel cost function threshold based soft information decision feedback method. The second one is ICI aware progressive iterative MIMO-OFDM receiver, which adapts and increases the progressions according to the level of ICI present in the received signal, while fully utilizing the soft information from the previous iterations, therefore reducing the complexity. Orthogonal Matching pursuit (OMP) channel estimation, low density parity check (LDPC) decoding and minimum mean square error (MMSE) equalization schemes are exploited by both the receivers. The proposed receivers are analyzed and compared with the standard Alamouti MIMO receiver as a reference and also compared with the non-iterative, basic turbo iterative and non-progressive iterative MIMO receivers. Simulations and experimental results prove the efficiency and effectiveness of the proposed receivers.

scholarly journals Cost Function based Soft Feedback Iterative Channel Estimation in OFDM Underwater Acoustic Communication

2019 ◽  
pp. 29-37
Author(s):  
Gang Qiao ◽  
Zeeshan Babar ◽  
Lu Ma ◽  
Xue Li
Keyword(s):  
Channel Estimation ◽  
Cost Function ◽  
Orthogonal Frequency Division Multiplexing ◽  
Matching Pursuit ◽  
Decision Feedback ◽  
Underwater Acoustic Communication ◽  
Soft Decision ◽  
Iterative Receiver ◽  
Iterative Receivers ◽  
Underwater Acoustic

Underwater Acoustic (UWA) communication is mainly characterized by bandwidth limited complex UWA channels. Orthogonal Frequency Division Multiplexing (OFDM) solves the bandwidth problem and an efficient channel estimation scheme estimates the channel parameters. Iterative channel estimation refines the channel estimation by reducing the number of pilots and coupling the channel estimator with channel decoder. This paper proposes an iterative receiver for OFDM UWA communication, based on a novel cost function threshold driven soft decision feedback iterative channel technique. The receiver exploits orthogonal matching pursuit (OMP) channel estimation and low density parity check (LDPC) coding techniques after comparing different channel estimation and coding schemes. The performance of the proposed receiver is verified by simulations as well as sea experiments. Furthermore, the proposed iterative receiver is compared with other non-iterative and soft decision feedback iterative receivers.

scholarly journals Iterative Interference Cancellation for Multi-Carrier Modulation in MIMO-DWT Downlink Transmission

2021 ◽  
Vol 9 (4) ◽  
pp. 75-87
Author(s):  
Yahya Harbi ◽  
ALI AL-JANABI ◽  
Hayder Almusa ◽  
Marwa Chafii ◽  
Alister Burr
Keyword(s):  
Interference Cancellation ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Minimum Mean Square Error ◽  
Multiple Input Multiple Output ◽  
Multipath Channel ◽  
Discrete Wavelet ◽  
Ldpc Decoder ◽  
Mimo Ofdm ◽  
Iterative Interference Cancellation

The Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) scheme represents the dominant radio interface for broadband multicarrier communication systems. However, with insufficient Cyclic Prefixes (CP), Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI) occur due to the time-varying multipath channel. This means that the performance of the system will be degraded. In this paper, we investigate the interference problem for a MIMO Discrete Wavelet Transform (MIMO-DWT) system under the effect of the downlink LTE channel. A Low-Density Parity-Check (LDPC) decoder is used to estimate the decoded signal. The proposed iterative algorithm uses the estimated decoded signal to compute the components required for ICI/ISI interference reduction. In this paper, Iterative Interference Cancellation (IIC) is employed to mitigate the effects of interference that contaminates the received signal due to multiple antenna transmission and a multipath channel. An equalizer with minimum mean square error is considered. We compare the performance of our proposed algorithm with the traditional MIMO-OFDM scheme in terms of bit error probability under insufficient CP. Simulation results verify that significant improvements are achieved by using IIC and MIMO-IIC for both systems.

Reliability Analysis of Turbo Code for High-Speed Underwater Acoustic Communication Based on OFDM

2013 ◽  
Vol 475-476 ◽  
pp. 832-837
Author(s):  
Lin Zhou ◽  
Lan Jun Liu ◽  
Shu Kai Chi
Keyword(s):  
Acoustic Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Data Transfer ◽  
Turbo Code ◽  
Rapid Development ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Advantages And Disadvantages ◽  
Coding Scheme

With the rapid development of OFDM (Orthogonal Frequency Division Multiplexing) technology and its own advantages, this technology has been studied actively in underwater acoustic communication recently to improve the data transfer rate and reliability. This paper introduces the key technology of high speed OFDM underwater acoustic communication, analyzes the advantages and disadvantages, design a high-speed underwater acoustic OFDM communication coding scheme based on TURBO code, and proceeding the simulation and analysis for the OFDM system. Finally, the reliability of TURBO code in high speed underwater acoustic OFDM communication is analyzed.

scholarly journals Partial Fractional Fourier Transform (PFrFT)-MIMO-OFDM for Known Underwater Acoustic Communication Channels

Information ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 469
Author(s):  
Yixin Chen ◽  
Carmine Clemente ◽  
John J. Soraghan
Keyword(s):  
Fractional Fourier Transform ◽  
Minimum Mean Square Error ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic Communications ◽  
Intercarrier Interference ◽  
Ofdm System ◽  
Doubly Selective Channels ◽  
Underwater Acoustic ◽  
Channel Information ◽  
Mimo Ofdm

Communication over doubly selective channels (both time and frequency selective) suffers from significant intercarrier interference (ICI). This problem is severe in underwater acoustic communications. In this paper, a novel partial fractional (PFrFT)-MIMO-OFDM system is proposed and implemented to further mitigate ICI. A new iterative band minimum mean square error (BMMSE) weight combining based on LDLH factorization is used in a scenario of perfect knowledge of channel information. The proposed method is extended from SISO-OFDM configuration to MIMO-OFDM. Simulation results demonstrate that the proposed PFrFT-LDLH outperforms the other methods in the SISO-OFDM scenario and that its performance can be improved in MIMO-OFDM scenarios.

scholarly journals A High-Speed and Low-Energy-Consumption Processor for SVD-MIMO-OFDM Systems

VLSI Design ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Hiroki Iwaizumi ◽  
Shingo Yoshizawa ◽  
Yoshikazu Miyanaga
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Multiple Input Multiple Output ◽  
Low Power Design ◽  
Ofdm Systems ◽  
Transmission Method ◽  
Real Time Processing ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
Value Decomposition

A processor design for singular value decomposition (SVD) and compression/decompression of feedback matrices, which are mandatory operations for SVD multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems, is proposed and evaluated. SVD-MIMO is a transmission method for suppressing multistream interference and improving communication quality by beamforming. An application specific instruction-set processor (ASIP) architecture is adopted to achieve flexibility in terms of operations and matrix size. The proposed processor realizes a high-speed/low-power design and real-time processing by the parallelization of floating-point units (FPUs) and arithmetic instructions specialized in complex matrix operations.

scholarly journals Low Complexity Submatrix Divided MMSE Sparse-SQRD Detection for MIMO-OFDM with ESPAR Antenna Receiver

VLSI Design ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Diego Javier Reinoso Chisaguano ◽  
Minoru Okada
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Minimum Mean Square Error ◽  
Multiple Input Multiple Output ◽  
Computational Cost ◽  
Low Complexity ◽  
Detection Process ◽  
Large Size ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Ofdm

Multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) with an electronically steerable passive array radiator (ESPAR) antenna receiver can improve the bit error rate performance and obtains additional diversity gain without increasing the number of Radio Frequency (RF) front-end circuits. However, due to the large size of the channel matrix, the computational cost required for the detection process using Vertical-Bell Laboratories Layered Space-Time (V-BLAST) detection is too high to be implemented. Using the minimum mean square error sparse-sorted QR decomposition (MMSE sparse-SQRD) algorithm for the detection process the average computational cost can be considerably reduced but is still higher compared with a conventional MIMOOFDM system without ESPAR antenna receiver. In this paper, we propose to use a low complexity submatrix divided MMSE sparse-SQRD algorithm for the detection process of MIMOOFDM with ESPAR antenna receiver. The computational cost analysis and simulation results show that on average the proposed scheme can further reduce the computational cost and achieve a complexity comparable to the conventional MIMO-OFDM detection schemes.

scholarly journals Impact of Equalizer step size in Underwater Acoustic Communication Channel

2021 ◽  
Vol 13 (1) ◽  
pp. 29-38
Author(s):  
Krishnamoorthy Raghavan Narasu ◽  
◽  
Immanuel Rajkumar ◽  
Jerry Alexander ◽  
Marshiana Devaerakkam
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Transmission Rate ◽  
Path Loss ◽  
Decision Feedback ◽  
Underwater Acoustic Communication ◽  
Step Size ◽  
Underwater Acoustic ◽  
Multipath Effects ◽  
Attenuation Loss ◽  
Proper Filter

The Underwater Acoustic Channel (UAC) is a time variant channel and its multipath effects create ISI. This is one of the most important obstacles in the UAC channel which reduces the transmission rate. To remove this obstacle, a proper filter has to be designed in the receiver section. In this article, optimal step size for equalizer is computed and compared the results with the known techniques namely Decision Feedback Equalizer with interleave division multiple access (DFE IDMA) and Cyclic Prefix - Orthogonal Frequency Division Multiplexing (CP-OFDM) Equalizer. Channels are modeled using ray tracing methods. The various factors considered are ambient noise, attenuation loss, bottom and surface loss. The overall path loss for channels is computed by summing up the attenuation loss, surface and bottom loss. Simulation results evident that for short range UAC channel, the BER in the order of 10-2 is achieved using proposed methodology with least Eb/No compared to standard DFE method.

A companding approach for PAPR suppression in OFDM based massive MIMO system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajay Kumar Yadav ◽  
Pritam Keshari Sahoo ◽  
Yogendra Kumar Prajapati
Keyword(s):  
Massive Mimo ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Base Station ◽  
Convex Optimization Problem ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Ofdm

Abstract Orthogonal frequency division multiplexing (OFDM) based massive multiuser (MU) multiple input multiple output (MIMO) system is popularly known as high peak-to-average power ratio (PAPR) issue. The OFDM-based massive MIMO system exhibits large number of antennas at Base Station (BS) due to the use of large number of high-power amplifiers (HPA). High PAPR causes HPAs to work in a nonlinear region, and hardware cost of nonlinear HPAs are very high and also power inefficient. Hence, to tackle this problem, this manuscript suggests a novel scheme based on the joint MU precoding and PAPR minimization (PP) expressed as a convex optimization problem solved by steepest gradient descent (GD) with μ-law companding approach. Therefore, we develop a new scheme mentioned to as MU-PP-GDs with μ-law companding to minimize PAPR by compressing and enlarging of massive MIMO OFDM signals simultaneously. At CCDF = 10−3, the proposed scheme (MU-PP-GDs with μ-law companding for Iterations = 100) minimizes the PAPR to 3.70 dB which is better than that of MU-PP-GDs, (iteration = 100) as shown in simulation results.

scholarly journals Parallel Resampling of OFDM Signals for Fluctuating Doppler Shifts in Underwater Acoustic Communication

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Shingo Yoshizawa ◽  
Takashi Saito ◽  
Yusaku Mabuchi ◽  
Tomoya Tsukui ◽  
Shinichi Sawada
Keyword(s):  
Conventional Method ◽  
Acoustic Communication ◽  
Orthogonal Frequency Division Multiplexing ◽  
Carrier Frequency Offset ◽  
Autonomous Underwater Vehicles ◽  
Underwater Vehicles ◽  
Error Rates ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Parallel Resampling

Reliable underwater acoustic communication is demanded for autonomous underwater vehicles (AUVs) and remotely operated underwater vehicles (ROVs). Orthogonal frequency-division multiplexing (OFDM) is robust with multipath interference; however, it is sensitive to Doppler. Doppler compensation is given by two-step processing of resampling and residual carrier frequency offset (CFO) compensation. This paper describes the improvement of a resampling technique. The conventional method assumes a constant Doppler shift during a communication frame. It cannot cope with Doppler fluctuation, where relative speeds between transmitter and receiver units are fluctuating. We propose a parallel resampling technique that a resampling range is extended by measured Doppler standard deviation. The effectiveness of parallel resampling has been confirmed in the communication experiment. The proposed method shows better performance in bit error rates (BERs) and frame error rates (FERs) compared with the conventional method.

scholarly journals Covert Communication in MIMO-OFDM System Using Pseudo Random Location of Fake Subcarriers

2016 ◽  
Vol 4 (1) ◽  
pp. 150-163 ◽  
Author(s):  
Rizky Pratama Hudhajanto ◽  
I Gede Puja Astawa ◽  
Amang Sudarsono
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Random Sequence ◽  
Multiple Input Multiple Output ◽  
Ofdm System ◽  
Transmission Scheme ◽  
Sensitive Data ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
Random Location

Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is the most used wireless transmission scheme in the world. However, its security is the interesting problem to discuss if we want to use this scheme to transmit a sensitive data, such as in the military and commercial communication systems. In this paper, we propose a new method to increase the security of MIMO-OFDM system using the change of location of fake subcarrier. The fake subcarriers’ location is generated per packet of data using Pseudo Random sequence generator. The simulation results show that the proposed scheme does not decrease the performance of conventional MIMO-OFDM. The attacker or eavesdropper gets worse Bit Error Rate (BER) than the legal receiver compared to the conventional MIMO-OFDM system.

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