Soft-combining schemes for JPEG image transmission over wireless channels

The evolution of digital mobile communications along with the increase of integrated circuit complexity has resulted in frequent use of error control coding to protect information against transmission errors. Soft decision decoding methods, such as the maximum a posteriori (MAP) decoding algorithm, process soft information and aim at minimizing bit error rate. This paper investigates application of a trellis-based MAP decoding approach to JPEG image transmission in wireless channels. When used with a soft-combining technique, it is shown to improve the performance significantly. This facilitates transmission of highly error-sensitive JPEG images in mobile radio systems, even when the ratio of average bit energy to noise power spectral density is quite low.