A new zero-acquisition time spreading/despreading technique for spread-spectrum communication systems

In direct sequence (DS) spread-spectrum systems, correlation techniques are used to extract information from the received signal. The various correlation procedures used in established DS systems offer a tradeoff between acquisition time, correlator complexity, and system performance. The paper introduces a new spread-spectrum technique which employs an easily implemented spreading/despreading mechanism that despreads the received signal immediately upon its reception. The data signal is spread through modulo-2 division using shift register techniques and despread through multiplication using a delay-and-multiply circuit. Since the sequence transmitted is a quotient, the technique is called transmitted-quotient direct sequence (TQ-DS). Preliminary performance results indicate that the cost of zero-acquisition time and low complexity is a significant degradation in system bit error rate (BER) performance relative to that of established spread-spectrum systems