scholarly journals Asynchronous Chirp Slope Keying for Underwater Acoustic Communication

2021 ◽  
Author(s):  
Dominik Jan Schott ◽  
Andrea Gabbrielli ◽  
Wenxin Xiong ◽  
Georg Fischer ◽  
Fabian Höflinger ◽  
...  
Keyword(s):  
Rayleigh Fading ◽  
Additive White Gaussian Noise ◽  
Data Rate ◽  
Error Rates ◽  
Dual Band ◽  
Underwater Acoustic Communication ◽  
Signal To Noise ◽  
Error Level ◽  
Time Bandwidth Product ◽  
Mode A

We propose an asynchronous acoustic chirp slope keying to map bit sequences on single or multiple bands without preamble or error correction coding on the physical layer. Details of the implementation are disclosed and discussed, the performance verified on laboratory scale in a pool measurement, as well as simulated for a channel containing Rayleigh fading and Additive White Gaussian Noise. For time-bandwidth products of 50 in single band mode, a raw data rate of 100~bit/s is simulated to achieve bit error rates below 0.001 for signal-to-noise ratios above -6~dB. In dual-band mode and a data rate of 200~bit/s, this bit error level was achieved for signal-to-noise ratios above 0~dB for time-bandwidth product of 25. The packet error rates follow this behavior with an offset of 1~dB.

scholarly journals Asynchronous Chirp Slope Keying for Underwater Acoustic Communication

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3282
Author(s):  
Dominik Jan Schott ◽  
Andrea Gabbrielli ◽  
Wenxin Xiong ◽  
Georg Fischer ◽  
Fabian Höflinger ◽  
...  
Keyword(s):  
Matched Filter ◽  
Additive White Gaussian Noise ◽  
Data Rate ◽  
Error Rates ◽  
Dual Band ◽  
Underwater Acoustic Communication ◽  
Signal To Noise ◽  
Detection Scheme ◽  
Symbol Timing ◽  
Symbol Detection

We propose an asynchronous acoustic chirp slope keying to map short bit sequences on single or multiple bands without preamble or error correction coding on the physical layer. We introduce a symbol detection scheme in the demodulator that uses the superposed matched filter results of up and down chirp references to estimate the symbol timing, which removes the requirement of a preamble for symbol synchronization. Details of the implementation are disclosed and discussed, and the performance is verified in a pool measurement on laboratory scale, as well as the simulation for a channel containing Rayleigh fading and Additive White Gaussian Noise. For time-bandwidth products (TB) of 50 in single band mode, a raw data rate of 100 bit/s is simulated to achieve bit error rates (BER) below 0.001 for signal-to-noise ratios above −6 dB. In dual-band mode, for TB of 25 and a data rate of 200 bit/s, the same bit error level was achieved for signal-to-noise ratios above 0 dB. The simulated packet error rates (PER) follow the general behavior of the BER, but with a higher error probability, which increases with the length of bits in each packet.

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.

PERFORMANCE OF QAM-OFDM SYSTEM OVER RAYLEIGH FADING CHANNEL IN WEI BULL NOISE DISTRIBUTION

2021 ◽  
Vol 25 (Special) ◽  
pp. 1-157-1-166
Author(s):  
Nabaa I. Abed ◽  
◽  
Ghanim A.AL Rubaye ◽  
Keyword(s):  
Fading Channels ◽  
Communication Networks ◽  
Orthogonal Frequency Division Multiplexing ◽  
Rayleigh Fading ◽  
Additive White Gaussian Noise ◽  
Wireless Networking ◽  
Ofdm System ◽  
Exact Match ◽  
Communication Industry ◽  
Non Gaussian

The phenomenal increase in the usage of mobile devices and wireless networking tools in recent years has resulted in the communication industry needing higher data speeds for connections and bandwidth. As a result, multi-carrier modulation has been suggested as a reliable and effective method of transmitting data over difficult communication networks such as selective fading channels. Orthogonal Frequency Division Multiplexing (OFDM) is a highly effective multi-carrier technique that can meet users' high demands. Many studies have looked into this technique, mostly as a way to counteract fading and Additive White Gaussian Noise (AWGN). As a result, the performance evaluation of the QAM-OFDM system in the presence of multi-path Rayleigh fading in Weibull noise is examined in this article. Furthermore, bit error rate performance (BER) is computed using the optimal derivation of the real system contaminated by compound Gaussian and non-Gaussian (Weibull) noise distributions at the OFDM demodulator output. The derived result is an exact match to the simulated result over various scenarios introduced by the MATLAB software package.

scholarly journals Direct-Mapping-Based MIMO-FBMC Underwater Acoustic Communication Architecture for Multimedia Signals

2019 ◽  
Vol 10 (1) ◽  
pp. 233 ◽  
Author(s):  
Chin-Feng Lin ◽  
Tsung-Jen Su ◽  
Hung-Kai Chang ◽  
Chun-Kang Lee ◽  
Shun-Hsyung Chang ◽  
...  
Keyword(s):  
Channel Estimation ◽  
Multimedia Communication ◽  
Error Rates ◽  
Transmission Mechanism ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Communication Architecture ◽  
Direct Mapping ◽  
Mean Square Errors ◽  
The Voice

In this paper, a direct-mapping (DM)-based multi-input multi-output (MIMO) filter bank multi-carrier (FBMC) underwater acoustic multimedia communication architecture (UAMCA) is proposed. The proposed DM-based MIMO-FBMC UAMCA is rare and non-obvious in the underwater multimedia communication research topic. The following are integrated into the proposed UAMCA: A 2 × 2 DM transmission mechanism, a (2000, 1000) low-density parity-check code encoder, a power assignment mechanism, an object-composition petrinet mechanism, adaptive binary phase shift keying modulation and 4-offset quadrature amplitude modulation methods. The multimedia signals include voice, image, and data. The DM transmission mechanism in different spatial hardware devices transmits different multimedia packets. The proposed underwater multimedia transmission power allocation algorithm (UMTPAA) is simple, fast, and easy to implement, and the threshold transmission bit error rates (BERs) and real-time requirements for voice, image, and data signals can be achieved using the proposed UMTPAA. The BERs of the multimedia signals, data symbol error rates of the data signals, power saving ratios of the voice, image and data signals, mean square errors of the voice signals, and peak signal-to-noise ratios of the image signals, for the proposed UAMCA with a perfect channel estimation, and channel estimation errors of 5%, 10%, and 20%, respectively, were explored and demonstrated. Simulation results demonstrate that the proposed 2 × 2 DM-based MIMO-FBMC UAMCA is suitable for low power and high speed underwater multimedia sensor networks.

scholarly journals A Deterministic Construction for Jointly Designed Quasicyclic LDPC Coded-Relay Cooperation

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Muhammad Asif ◽  
Wuyang Zhou ◽  
Qingping Yu ◽  
Xingwang Li ◽  
Nauman Ali Khan
Keyword(s):  
Fading Channels ◽  
Iterative Decoding ◽  
Rayleigh Fading ◽  
Additive White Gaussian Noise ◽  
Ldpc Codes ◽  
Destination Node ◽  
Relay Nodes ◽  
Binary Matrix ◽  
Relay Cooperation ◽  
Joint Iterative Decoding

This correspondence presents a jointly designed quasicyclic (QC) low-density parity-check (LDPC) coded-relay cooperation with joint-iterative decoding in the destination node. Firstly, a design-theoretic construction of QC-LDPC codes based on a combinatoric design approach known as optical orthogonal codes (OOC) is presented. Proposed OOC-based construction gives three classes of binary QC-LDPC codes with no length-4 cycles by utilizing some known ingredients including binary matrix dispersion of elements of finite field, incidence matrices, and circulant decomposition. Secondly, the proposed OOC-based construction gives an effective method to jointly design length-4 cycles free QC-LDPC codes for coded-relay cooperation, where sum-product algorithm- (SPA-) based joint-iterative decoding is used to decode the corrupted sequences coming from the source or relay nodes in different time frames over constituent Rayleigh fading channels. Based on the theoretical analysis and simulation results, proposed QC-LDPC coded-relay cooperations outperform their competitors under same conditions over the Rayleigh fading channel with additive white Gaussian noise.

scholarly journals Coexistence of Cognitive Small Cell and WiFi System: A Traffic Balancing Dual-Access Resource Allocation Scheme

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Xiaoge Huang ◽  
Yangyang Li ◽  
She Tang ◽  
Qianbin Chen
Keyword(s):  
Power Allocation ◽  
Optimization Problems ◽  
Holistic Approach ◽  
Data Rate ◽  
Small Cell ◽  
Dual Band ◽  
Cell Selection ◽  
Allocation Scheme ◽  
Traffic Balancing ◽  
Unlicensed Bands

We consider a holistic approach for dual-access cognitive small cell (DACS) networks, which uses the LTE air interface in both licensed and unlicensed bands. In the licensed band, we consider a sensing-based power allocation scheme to maximize the sum data rate of DACSs by jointly optimizing the cell selection, the sensing operation, and the power allocation under the interference constraint to macrocell users. Due to intercell interference and the integer nature of the cell selection, the resulting optimization problems lead to a nonconvex integer programming. We reformulate the problem to a nonconvex power allocation game and find the relaxed equilibria, quasi-Nash equilibrium. Furthermore, in order to guarantee the fairness of the whole system, we propose a dynamic satisfaction-based dual-band traffic balancing (SDTB) algorithm over licensed and unlicensed bands for DACSs which aims at maximizing the overall satisfaction of the system. We obtain the optimal transmission time in the unlicensed band to ensure the proportional fair coexistence with WiFi while guaranteeing the traffic balancing of DACSs. Simulation results demonstrate that the SDTB algorithm could achieve a considerable performance improvement relative to the schemes in literature, while providing a tradeoff between maximizing the total data rate and achieving better fairness among networks.

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