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Abstract

Method and apparatus for tracking the frequency and phase of signals in spread spectrum communication systems that makes more efficient use of available carrier frequency and phase information by utilizing a substantial portion or all of the energy occupying the frequency spectrum of a received carrier signal, including energy from communication signals intended for other system users. Multiple spread spectrum communication signals are input in parallel to data receivers where they are despread using preselected despreading codes at an adjustable phase angle and decoded over multiple orthogonal codes active within the communication system. Multiple decoded signals are then combined to form a single phase detection signal which is used by at least one tracking loop to track frequency and phase of the carrier signal for the received communication signals. The tracking loop generates a timing signal which is used to adjust the phase angle used during despreading. In further embodiments, the communication signals are despread using appropriate PN codes and separated into in-phase (I) and quadrature channels (Q) where data symbols are processed by fast Hadamard transformers to generate corresponding data bits. The data is formed into pairwise products between the channels and summed over multiple or all active subscriber orthogonal codes. This sum indicates a degree to which the estimated phase differs from the actual phase of received communication signals and is used to adjust the phase of application for the PN codes.

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