Comparison of coherent and non-coherent modulation schemes for low-data rate hand-held satellite terminals subject to high phase noise

Abstract In this paper, a theoretical investigation was suggested to study underwater wireless optical communication (UWOC) system based on multiple input–multiple output (MIMO) technique. The modulation schemes such as RZ-OOK, NRZ-OOK, 32-PPM and 4-QAM applied under different coastal water types. MIMO technique enabled the system to transmit data rate with longer distance link. The performance of the proposed system examined by BER and data rate as a metrics. Several impairments such as the types of water by the attenuation of coastal water and the distance link were taken into account for the transmission of the optical signal to appreciate the reliability of the MIMO technique. The theoretical analysis shows the proposed of MIMO (4Tx/4Rx) technique get the better performance compared with the other techniques in terms of BER. When 32-PPM is applied as a modulation scheme. For the system with MIMO technique the maximum distance link arrive to 14.9 and 2.9 m for coastal water types JIC and J9C, respectively. While SISO (1Tx/1Rx) technique achieved the maximum distance link are 10 and 2.3 m for coastal water types JIC and J9C, respectively. Therefore, 32-PPM can outperform the other modulation schemes and consider the suitable option for obtaining a low BER with the best maximum distance link for LoS of MIMO technique.

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Performance Research on Variable Data Rate Reconfigurable Architecture for SDR Receiver

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b1002.0882s819 ◽

2019 ◽

Vol 8 (2S8) ◽

pp. 1008-1011

Keyword(s):

Software Defined Radio ◽

Data Rate ◽

Reconfigurable Architecture ◽

Bandwidth Efficiency ◽

High Data ◽

Modulation And Demodulation ◽

Data Rates ◽

Modulation Schemes ◽

Variable Data ◽

Amplitude And Frequency Modulation

In Early days, communications systems used amplitude and frequency modulation schemes in which bandwidth constraint is one of the major challenge to accommodate more data rates. As the data rate requirement increased drastically till date, The applications demands more data rates for communication using less bandwidth is considered as an efficient communication system. For achieving communication with high data rates using less bandwidth, technology migrated to digital modulation schemes. In this phase new modulation techniques like ASK, FSK, PSK were realised. ASK and FSK modulation schemes bandwidth efficiency is less as compared to PSK schemes. For best utilisation of bandwidth efficiency and less inherent noise levels, PSK schemes are used, which is suitable for high data rate applications. In this paper QPSK modulation and demodulation technique is selected for realising the variable data rate in the range of 1.2MBPS as the best bandwidth with efficient reconfigurable architecture designed for software defined radio receiver.

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