Abstract: A system for acquiring a received spread spectrum signal having a code component, the acquiring including matching the phase of a replica of the code component to the phase of the received code component and also determining a possible shift in the carrier frequency away from a nominal carrier frequency, the acquiring having an intrinsic bandwidth that is substantially the inverse of a predetermined fraction of a code period and also having a design bandwidth that is a fraction of the intrinsic bandwidth including possibly the entire intrinsic bandwidth, the system including means for performing various correlations over sections of a code period, the number of sections determining the intrinsic bandwidth, and adjusting the design bandwidth to be possibly less than the intrinsic bandwidth, so as to alter the characteristics of the acquisition.

Abstract: Systems and methods are described for carrier tracking. A center frequency of a signal is tracked by comparing spectral power contents of filtered versions of the signal. A receiver incorporates this carrier tracking. The systems and methods provide advantages because of decreased cost.

Abstract: A real-time multi-user detection (MUD) receiver processing simultaneous digitally modulated interferers and transmissions in the same frequency optimizing performance for heavily loaded and overloaded multiple access systems by implementing an iterative TurboMUD receiver using tree-pruning, including confidence ordering, power-ordering, and a voting procedure. On the first iteration, user indices are ordered according to received powers. On subsequent iterations, the voting system provides soft decisions or confidence values utilized as soft inputs to single-user decoders. Voting is computationally attractive and allows the bank of decoders to operate on soft values, improving performance and reducing the number of turboMUD iterations. The bank of soft output error correction decoders produces an improved set of soft decisions or confidence values corresponding to the channel bits transmitted by each interfering user.

Abstract: In a CDMA receiver used in a CDMA cellular mobile telephone system, a searcher which is used to determine reception timing of a plurality of finger processing portions is operated in a time division fashion to enable wide searching range without any expansion of a size. Specifically, a plurality of correlators and/or adders are controlled in a time division fashion to decrease the number of the correlators and/or the adders together with registers for storing integrated correlation value signals.

Abstract: The performance of a RAKE receiver for indoor multipath WLAN applications on direct sequence spread spectrum signals having relatively short codeword lengths comprises a channel-matched filter and codeword correlator front end, plus a signal combiner to which the codeword correlation component is applied. The signal combiner is supplied with a bias-corrected input calculated by a distorted codeword signature (power) generator, which is operative to generate and store a set of N codeword power correction values. The signal combiner combines correction values into the codeword correlation for each potentially transmitted codeword Sk. This serves to correct each correlation codeword metric by a de-biasing power component |Sk|2 for the unequal multipath-based distortions of the codeword energies. The output of the signal combiner is coupled to a peak detector, which selects a minimum distance-based ‘de-biased’ output as the transmitted codeword.

Abstract: In a method of calculating a variable spectral compression filter coefficient in a BTSC compatible stereo encoder from a feedback variable, a reciprocal value that is proportional to a reciprocal of the feedback variable is calculated. A lookup table is indexed using a preselected set of bits of the reciprocal value to generate at least one parameter of the filter coefficient function. An approximation of the compression filter coefficient is linearly interpolated based on the at least one parameter of the filter coefficient function. An apparatus that includes circuitry that calculates a variable spectral compression filter coefficient in a BTSC compatible stereo encoder from a feedback variable includes a reciprocal value circuit that calculates a proportional to a reciprocal value of the feedback variable.

Abstract: An information transmission/reception system includes a radio paging data transmitter equipped with a data segmentation block which segments transmission data into transmission data segmentation units to obtain data segments, and an information identification number addition block which adds a plurality of pieces of identification information to each data segment in order to identify the transmission data. A sequence information addition block adds sequence information to each data segment in the sequence in which it is segmented, and a transmission processing block which performs transmission processing so that data segments to which different identification information is added are assigned within a single data transmission cycle. A radio paging data receiver of the information transmission/reception system is equipped with an information identification number discrimination block which performs the discrimination of data segments from the information identification number.