Image transmission systems through CDMA channels using spreading sequences of variable-period

Image transmission systems using spread spectrum techniques are discussed. We transmit DCT coefficients of the image through CDMA channels. Within a limited bandwidth, in order to reduce the error rates of significant bits, we assign spreading sequences of longer period to more significant bits than to less ones. This technique is analogous to the Shannon-Fano encoding. It is found that spreading sequences of variable-period are useful in such image transmissions through CDMA channels.