Hierarchical Quadrature Amplitude Modulation （分层正交调幅）.pdf

International Journal of Video Image Processing and Network Security IJVIPNS-IJENS Vol: 11 No: 06 1 Hierarchical Quadrature Amplitude Modulation For Image Transmission Over Erroneous Wireless Channels Farid Ghani, Md. Abdul Kader, and R. Badlishah Ahmed This paper proposes the use of an asymmetric modulation Abstract—Bit dependency of image compression algorithms method known as Hierarchical Quadrature Amplitude introduce error extension effects in transmission of compressed Modulation (HQAM) for the transmission of images over images and considerably reduce the received image quality. wireless mobile channels. It is a modification of Quadrature Channel coding provides protection against these errors but at Amplitude Modulation (QAM) and provides unequal error the cost of increased bandwidth. Asymmetric modulation methods like QAM and QPSK provide alternative means of equal error protection (UEP). This is a simple and efficient approach in protection to all the coded bits without increasing the bandwidth. which non-uniform signal-constellation is used to give This paper examines the suitability of Hierarchical QAM different degrees of protection to the transmitted bits. The (HQAM) where non-uniform signal constellation is used to adva