Numerical simulation and experiment of the shallow water communication channel with time varying multipath effect using time reversal mirror

2012 ◽  
Vol 131 (4) ◽  
pp. 3277-3277
Author(s):  
Yi-Wei Lin ◽  
I Putu Andhi Indira Kusuma ◽  
Gee-Pinn Too
Keyword(s):  
Numerical Simulation ◽  
Shallow Water ◽  
Time Reversal ◽  
Communication Channel ◽  
Time Varying ◽  
Multipath Effect ◽  
Simulation And Experiment ◽  
Time Reversal Mirror

scholarly journals Pengaruh Gerakan Transducer Terhadap Kualitas Sinyal Akustik Bawah Air Dengan Pendekatan Simulasi

2018 ◽  
Vol 8 (2) ◽  
pp. 158
Author(s):  
Andhi Indira Kusuma I Putu ◽  
Maria Margareta Zau Beu ◽  
Maria Margareta Zau Beu
Keyword(s):  
Phase Shift ◽  
Time Reversal ◽  
Phase Shift Keying ◽  
Multipath Effect ◽  
Binary Phase ◽  
Shift Keying ◽  
Time Reversal Mirror ◽  
Binary Phase Shift Keying

Pada proses transmisi sinyal akustik bawah air di perairan dangkal yang bergelombang akan mengakibatkan pergerakan transducer yang secara tidak langsung akan meningkatkan gangguan pada proses transmisi sinyal. Makalah ini menganalisa pengaruh pergerakan transducer terhadap kualitas sinyal komunikasi akustik bawah air dengan pendekatan simulasi serta menerapkan metode passive time reversal mirror (PTRM) sebagai metode pemrosesan sinyal untuk meminimalisir pengaruh multipath effect dan meningkatkan kualitas sinyal. Pemodelan metode image digunakan untuk memodelkan kanal beserta interaksi sinyal yang terjadi saat proses transimisi. Dimana, tanki uji tarik kapal digunakan sebagai kanal atau media transmisi sinyal komunikasi akustik. Tiga jarak komunikasi antara sumber dan penerima sinyal disimulasikan kedalam pemodelan dengan mentransimisikan sinyal akustik Binary Phase Shift Keying (BPSK) sebesar 10 kHz dan membawa 100 bits simbol transmisi dengan waktu transmisi selama 0.02 s. Kemudian tiga variasi nilai sigma (s) 2.5 cm, 5 cm dan 10 cm diberikan sebagai representasi gerakan osilasi dari transducer dengan sebaran Gaussian. Dari hasil pemodelan didapatkan bahwa semakin jauh jarak komunikasi maka nilai bit error akan meningkat. Kemudian semakin besar pergerakan transducer atau nilai sigma  (s)  maka semakin acak waktu kedatangan pada setiap elemen ray di masing-masing respon impulse dari kanal sehingga nilai bit error akan meningkat pula. Dengan menerapkan serta mengaplikasikan metode passive time reversal maka bit error dapat diminimalisir sehingga dapat meningkatkan kualitas sinyal akustik yang diterima.. Dalam hal ini metode passive time reversal efektif untuk mengurangi pengaruh yang ditimbulkan oleh pergerakan transducer.

scholarly journals Numerical simulation study on bowtie antenna-based time reversal mirror for super-resolution target detection

2019 ◽  
Vol 70 (3) ◽  
pp. 236-243 ◽  
Author(s):  
Baidenger Agyekum Twumasi ◽  
Jia-Lin Li
Keyword(s):  
Numerical Simulation ◽  
Target Detection ◽  
Simulation Study ◽  
Time Reversal ◽  
Electromagnetic Waves ◽  
Super Resolution ◽  
Dual Band ◽  
Bowtie Antenna ◽  
Time Reversal Mirror ◽  
First Time

Abstract Bowtie antenna-based time reversal mirror (TRM), incorporating with randomly distributed and arbitrarily shaped wire metamaterials medium, is proposed to realize super-resolution target detection. The achieved performance for standard and scatterer bowtie antenna TRM is compared and discussed. The dual-band bowtie antennas resonate at 2.45 GHz and 5.2 GHz and a super-resolution of 0.0817 of the free-space wavelength at 2.45 GHz has been achieved. For the first time, studies show that the TRM with microstructure perturbations (namely scatterers) can enhance the resolution in some cases. Proposing a method of super-resolving transmission of electromagnetic waves is very important to realize multi-independent channels in a compact space for the related applications.

NUMERICAL SIMULATION OF TWO-PHASES FLOW ON PUMPS INLET SYSTEM FOR SHALLOW WATER

2019 ◽  
Author(s):  
Livio Sebastián Maglione ◽  
Guillermo Muschiatto ◽  
Raúl Alberto DEAN
Keyword(s):  
Numerical Simulation ◽  
Shallow Water ◽  
Inlet System ◽  
Two Phases ◽  
Two Phases Flow

scholarly journals Locating Ships Using Time Reversal and Matrix Pencil Method by Their Underwater Acoustic Signals

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5065
Author(s):  
Daniel Chaparro-Arce ◽  
Sergio Gutierrez ◽  
Andres Gallego ◽  
Cesar Pedraza ◽  
Felix Vega ◽  
...  
Keyword(s):  
Time Reversal ◽  
Communication Channel ◽  
Matrix Pencil ◽  
Acoustic Signals ◽  
Underwater Acoustic ◽  
Low Bit Rate ◽  
Matrix Pencil Method ◽  
The Matrix ◽  
Resonance Expansion ◽  
Passive Sensors

This paper presents a technique, based on the matrix pencil method (MPM), for the compression of underwater acoustic signals produced by boat engines. The compressed signal, represented by its complex resonance expansion, is intended to be sent over a low-bit-rate wireless communication channel. We demonstrate that the method can provide data compression greater than 60%, ensuring a correlation greater than 93% between the reconstructed and the original signal, at a sampling frequency of 2.2 kHz. Once the signal was reconstituted, a localization process was carried out with the time reversal method (TR) using information from four different sensors in a simulation environment. This process sought to achieve the identification of the position of the ship using only passive sensors, considering two different sensor arrangements.

scholarly journals M-ary nonlinear sine chirp spread spectrum for underwater acoustic communication based on virtual time-reversal mirror method

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Songzuo Liu ◽  
Habib Hussain Zuberi ◽  
Yi Lou ◽  
Muhmmad Bilal Farooq ◽  
Shahabuddin Shaikh ◽  
...  
Keyword(s):  
Acoustic Communication ◽  
Time Reversal ◽  
Spread Spectrum ◽  
Underwater Acoustic Communication ◽  
Half Cycle ◽  
Spreading Factor ◽  
Underwater Acoustic ◽  
Virtual Time ◽  
Chirp Spread Spectrum ◽  
Time Reversal Mirror

AbstractLinear chirp spread spectrum technique is widely used in underwater acoustic communication because of their resilience to high multipath and Doppler shift. Linear frequency modulated signal requires a high spreading factor to nearly reach orthogonality between two pairs of signals. On the other hand, nonlinear chirp spread spectrum signals can provide orthogonality at a low spreading factor. As a result, it improves spectral efficiency and is more insensitive to Doppler spread than the linear counterpart. To achieve a higher data rate, we propose two variants (half cycle sine and full cycle sine) of the M-ary nonlinear sine chirp spread spectrum technique based on virtual time-reversal mirror (VTRM). The proposed scheme uses different frequency bands to transmit chirp, and VTRM is used to improve the bit error rate due to high multipath. Its superior Doppler sensitivity makes it suitable for underwater acoustic communication. Furthermore, the proposed method uses a simple, low-power bank of matched filters; thus, it reduces the overall system complexity. Simulations are performed in different underwater acoustic channels to verify the robustness of the proposed scheme.

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