Abstract: The exemplary embodiments of the invention provide methods, computer program products and apparatus for determining cross-correlations between the received signals in a set of users. An exemplary method includes: receiving an input signal comprising a plurality of user signals, selecting a first received signal and a second received signal from the plurality of user signals, determining a timing offset between the first signal and the second signal, and using the determined timing offset, a first identification of the first signal, and a second identification of the second signal as indices to retrieve at least one cross-correlation coefficient from a memory.