SYNCHRONIZATION AND BIT DETECTION IN A SINGLE SPREADING SEQUENCE SAMA RECEIVER

摘要

In simultaneous reception of overlapping signals (61) sharing a single spreading sequence, packet start times (135) are found by separately demodulating, low pass filtering and despreading in-phase and quadrature components. Despread in-phase and quadrature signals are provided to synchronization filters (103, 105, 113, 115) connected in parallel and arranged in two identical pairs. Outputs from filters in different pairs are added, and the sums are squared. The squared signals are added. An exceeded threshold of the output from the last adder (129) decilitates a packet start. Knowing packet start times facilitates separating the overlapping inbound signals.