Multicarrier code division multiple access (MC-CDMA) technique for underwater acoustic communication networks using short spreading sequences

2004 ◽  
Vol 151 (4) ◽  
pp. 231 ◽  
Author(s):  
D.P. Konstantakos ◽  
A.E. Adams ◽  
B.S. Sharif
Keyword(s):  
Communication Networks ◽  
Acoustic Communication ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Code Division Multiple ◽  
Spreading Sequences

LMS Blind Adaptive Multiuser Detection for Underwater Acoustic Communication with MMSE and MOE Criteria

2014 ◽  
Vol 556-562 ◽  
pp. 5046-5051
Author(s):  
Zhong Qiu Qiu Wang ◽  
Zhen Wang ◽  
Hong Ru Wang ◽  
Jun Cheng Wang
Keyword(s):  
Multiuser Detection ◽  
Communication Networks ◽  
Acoustic Communication ◽  
Simulation Analysis ◽  
Detection Algorithm ◽  
Lms Algorithm ◽  
Underwater Acoustic Communication ◽  
Underwater Acoustic ◽  
Blind Adaptive ◽  
Adaptive Multiuser Detection

In order to solve detection of multi-user detection in underwater acoustic communication networks, blind adaptive multiuser detection method using LMS algorithm was proposed to solve the MAI problem of multi-user detection in underwater acoustic communication channel when users increase. Two type simulations were executed, including synchronous and asynchronous multi-user simulation analysis, to verify the validity of LMS multi-user detection algorithm and inspection machine. The verification of the effectiveness of the MMSE and MOE algorithm for LMS multi-user detection algorithm was done by simulation.

scholarly journals A fractional Fourier transform–based channel estimation algorithm in single-carrier direct sequence code division multiple access underwater acoustic communication system

2019 ◽  
Vol 15 (1) ◽  
pp. 155014771982600 ◽  
Author(s):  
Lin Zhou ◽  
Qingsheng Zhao ◽  
Shukai Chi ◽  
Yanlong Li ◽  
Lanjun Liu ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Communication System ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Fractional Fourier Transform ◽  
Direct Sequence ◽  
Underwater Acoustic ◽  
Single Carrier ◽  
Sequence Code ◽  
Code Division Multiple

Due to the complexity and variability of the underwater acoustic channel, the communication signal is affected by multi-path, time delay, and Doppler frequency shift. Based on the advantageous characteristics of fractional Fourier transform on chirp signal processing, a fractional Fourier transform–based algorithm using combined linear frequency–modulated signal is proposed, which can estimate parameters of underwater acoustic channel and has a better performance than the existing methods. To distinguish multi-user in underwater acoustic communication system, a single-carrier direct sequence code division multiple access communication system combined with the fractional Fourier transform–based algorithm is proposed. Thus, a preliminary study on underwater multi-target identification is carried out. The simulation and experimental results show that the fractional Fourier transform–based algorithm is simple and effective, and the energy can be focused at the “best” fractional order, which can directly determine the multi-path number and complete the channel estimation. The proposed single-carrier direct sequence code division multiple access communication system has good performance on bit error rate when we use corresponding spreading code to distinguish multi-user.

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