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Review Papers | Computer Science & Engineering | India | Volume 3 Issue 6, June 2014

Designing and Comparative Analysis of Image Transmission using Techniques HQAM and QAM

Neeru Sharma

Abstract: In transmission of compressed images; image compression algorithms introduce error extension effects and significantly reduce the received image quality. Channel coding can be used to provide protection against these errors but it demands increased bandwidth. Asymmetric modulation methods like QAM and QPSK provide alternative means of equal error protection to all the coded bits without increasing the bandwidth. This paper surveys the suitability of Hierarchical QAM (HQAM) where non-uniform signal constellation is used to provide different degrees of protection to the significant and non-significant bits in the compressed image data. Hierarchical quadrature amplitude modulation (HQAM) enables unequal priority transmission with the help of irregularly spaced constellations Hierarchical Quadrature Amplitude Modulation (HQAM) ; a modification of QAM; offers Unequal Error Protection (UEP) to the transferred bits for increasing the protection to the transferred bits as well as it is also efficient in bandwidth and power. This paper surveys about different image transmission techniques for achieving a high quality and high speed in digital image transmission in a band-limited fading channel

Keywords: OFDM, QAM, HQAM, PSNR, BER

Edition: Volume 3 Issue 6, June 2014,

Pages: 2606 - 2609