Vector tree correlator for variable spreading rates

摘要

A vector tree correlator correlates over received data spread at differing spreading rates or, over differing lengths of spreading sequence. When the maximum length sequence has a length N that is an integer power of 2, or 2^M, then the vector tree correlator is formed from M levels. Level ( 1 ) is formed of add/subtract logic units, and Level ( 2 ) through Level (M) are formed of adders. Add/subtract logic units each receive a pair of received signal samples and combines the received signal samples based on a control signal input. The control signal input is derived from the locally generated spreading sequence. The output of the adder at the top of the tree is the result of the length N correlation, while output tap points at different levels of the tree each provide a correlation for one of the different spreading rates of length 2^m, 1