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Investigation of VBLAST Equalization Technique for Underwater Acoustic Communications

Pranitha B., Anjaneyulu L., Minh Hoa, Aslam Nauman, Kumar Sandeep V.

International Journal of Electronics and Telecommunications

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2020

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Vol. 66, No. 2

331--337

EN

Underwater Acoustic Communications (UWAC) is an emerging technology in the field of underwater communications, and it is challenging because of the signal attenuation of the sound waves. Multiple Input and Multiple- Output (MIMO) is introduced in UWAC because of its support in enhancing the data throughput even under the conditions of interference, signal fading, and multipath. The paper presents the concept and analysis of 2 × 2 MIMO UWAC systems that uses a 4 - QAM spatial modulation scheme thus minimizing the decoding complexity and overcoming the Inter Channel Interference (IChI). Bit Error Rate (BER) investigation is carried out over different link distances under acoustic Line of Sight (LOS). The utilization of Zero Forcing (ZF) and Vertical-Bell Laboratories Layered Space-Time (VBLAST) equalizers, which estimates the transmitted data proves a success of removing Inter Symbol Interference (ISI). The ISI caused due to multipath effect and scattering in UWAC can be reduced by iterative process considered in VBLAST. A study is made on how the distance between the transmitter and the receiver and the Doppler Effect has its impact on the performance of the system.

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FPGA Implementation of Sphere Detector for Spatial Multiplexing MIMO System

Mohamed Asma, Zekry Abdel Halim, Ibrahim Reem

International Journal of Electronics and Telecommunications

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2019

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Vol. 65, No. 2

245--252

EN

Multiple Input Multiple Output (MIMO (techniques use multiple antennas at both transmitter and receiver for increasing the channel reliability and enhancing the spectral efficiency of wireless communication system.MIMO Spatial Multiplexing (SM) is a technology that can increase the channel capacity without additional spectral resources. The implementation of MIMO detection techniques become a difficult mission as the computational complexity increases with the number of transmitting antenna and constellation size. So designing detection techniques that can recover transmitted signals from Spatial Multiplexing (SM) MIMO with reduced complexity and high performance is challenging. In this survey, the general model of MIMO communication system is presented in addition to multiple MIMO Spatial Multiplexing (SM) detection techniques. These detection techniques are divided into different categories, such as linear detection, Non-linear detection and tree-search detection. Detailed discussions on the advantages and disadvantages of each detection algorithm are introduced. Hardware implementation of Sphere Decoder (SD) algorithm using VHDL/FPGA is also presented.

3

Signal detection methods for MIMO systems

Nadolna D.

Poznan University of Technology Academic Journals. Electrical Engineering

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2007

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No 54

157-164

EN

Multiple-input multiple-output, wireless systems are able to realize high spectral efficiency and high performance communication links. The benefits from using multiple antennas at the transmitter and receiver are associated with some costs. The most essential difficulty for this kind of systems is the increased complexity of recovering the transmitted signal. When the capacity rises linearly, the detection complexity increases exponentially. This paper presents an overview of the signal detection methods known in theory and particularly describes the main design approaches to MIMO systems: spatial multiplexing and transmit diversity. The article shows classes of receivers, which are used in these strategies. The most important algorithms with their assumptions and computational complexity are also discussed. The introduced receivers are briefly characterized and compared.