Using an adaptive UPA scheme with a channel-aware OFDM technique for wireless transmission of JPEG2000 images

In this paper, an adaptive scheme is developed for an Unequal Power Allocation (UPA) algorithm in a way to allow variable size grouping of the coding passes to enhance the optimization process at different Signal to Noise Ratio (SNR) values. The optimization algorithm exploits the hierarchical structure of the JPEG2000 images and uses a distortion model along with the channel state information (CSI) for allocating optimal values of power on each coding pass to minimize the end-to-end distortion. Orthogonal Frequency Division Multiplexing (OFDM) technique is incorporated within the transmitter to enable transmission of the JPEG2000 images over block fading frequency selective channels. In this paper, we propose a channel assignment strategy, within our OFDM transmitter, which passes the more important coding passes over the subcarriers with higher channel gain. Simulation results indicate an improvement of up to 2 dB in the decoded image quality and potentiality of energy conservation when the adaptive UPA scheme along with the channel assignment strategy are used.