Adaptive Detection With Intersymbol-Interference Cancellation for Distorted Digital Signals

A theoretical analysis is presented of an adaptive detector in a synchronous serial data-transmission system. A binary-coded signal is transmitted over a baseband channel, which introduces slowly time-varying signal distortion. The received signal is sampled and each signal element is detected by means of an iterative process that uses some or all sample values dependent on that element. The intersymbol interference of the signal element in the following elements is then canceled, before the detection of the next element, and so on. Immediately after the detection of each signal element, the channel impulse response is estimated and the detector is adjusted appropriately, so that it follows the variations in the channel transmission characteristics. No training signal is required except at the start of transmission. The tolerance to additive white Gaussian noise is evaluated for different arrangements of the basic system and for various values of the signal distortion in transmission, assuming the detector to be correctly matched to the channel.