A wavelet-based multirate/multimedia system

We present a new multirate/multimedia system, which we call scale-code division multiple access (SCDMA) that depends on the code, and time and scale orthogonality introduced by pseudo-noise (PN) sequences, and wavelets. Wavelets are used for signaling. In this system, the channel is divided into different scales, and each scale into time slots. In addition, the PN sequences are used in each scale to identify multiple users. In other words, each user encodes its successive information symbols with time-shifted replicas of the same basic wavelet in a specific scale and spreads its scaled and translated wavelets by its PN sequence. However, the finer the scale, the more the symbols are transmitted. We analyze this system over an asynchronous additive white Gaussian noise (AWGN) channel by using conventional detectors and show that it is attractive for multirate/multimedia applications due to its reasonable performance.