A Comparison between Different Modulations for an Image Transmission System through a Satellite Channel

Majlesi Journal of Telecommunication Devices

مقاله 4، دوره 1، شماره 2، شهریور 2012

نوع مقاله: Articles

چکیده

Regarding the importance of received images from satellite, in this research evaluating current methods in image coding, decoding and image transmission in order to obtain the best image quality has been done. In image coding two methods are used. Reversible Variable-Length Codes (RVLC), and Huffman codes which are based on Joint Photographic Experts Group (JPEG). Coded bits of image are transmitted through a satellite channel. At output, decoded bits reconstruct the received image. Transmitted image is compared with received image in accordance with Peak Signal to Noise Ratio (PSNR) to find the best method. Different parameters of satellite channel are examined while four different kind of modulation are tested. These modulations are; Quadrature Phase Shift Keying (QPSK), 8PSK, Binary Differential PSK (BDPSK), and 16 Quadrature Amplitude Modulation (16QAM). Under extreme noise conditions and No Line Of Sight (NLOS) between transmitter and receiver, RVLC coding accompanying BDPSK modulation is recognized as the best method. In line Of Sight (LOS), BDPSK and QPSK are the best Modulations. Simulations have been done by using MATLAB software.

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