DIRECT SEQUENCE SPREAD SPECTRUM METHOD, COMPUTER-BASED PRODUCT, APPARATUS AND SYSTEM TOLERANT TO FREQUENCY REFERENCE OFFSET

摘要

A system employs a digital receiver (Fig. 9) (or transceiver) to receive, digitize and process a direct sequence spread spectrum signal using digital signal processing components. A radio front end portion (905) of the receiver receives and digitizes the signal (907), and a digital signal processing portion downconverts (909) and despreads (911) the signal by applying a pseudorandom noise (PN) code, used at a transmitter to spread a data signal contained in the direct sequence spread spectrum signal, to the received signal. A timing and state control mechanism (921) is included to provide time reference correction information to the signal processing components of the receiver for alignment of the PN code with the direct sequence spread spectrum signal, allowing the receiver to be compatible with transmitter using inaccurate frequency references which impart a significant frequency ambiguity in the received signal. Computer-based synchronization methods and mechanism suitable for use for low performance digital signal processors, and power management mechanisms (925) are employed to enable long-term operations using battery power, enabling utilization in network setting.