ANOVEL WIRELESS IMAGE TRANSMISSION METHOD BASED WAVELET DECOMPOSITION ALGORITHM OVER FH-OFDM SYSTEM

摘要

In this paper, a new scheme for wireless image transmission is proposed. Firstly, based on wavelet decomposition theory, an image source can be decomposed into different weight levels. Then, the bit streams with different weight are modulated by FH-OFDM system, which can give low frequency bits more protection with help of hop frequency graphic design in FH-OFDM. A joint system combined with source coding and adaptive modulation method is introduced to give the image bit streams with different subcarriers, which eliminate ISI in low frequency streams more effectively. Therefore, a better reconstruction image can be obtained at receiver. Simulation results indicate that the scheme with joint source coding and adaptive modulation method can outperform the system without adaptive modulation in image quality. Under the same conditions, the proposed FH-OFDM system has better BER performance than traditional OFDM and better image quality than pseudorandom pattern FH-OFDM in the process of wireless image transmission.