Abstract: A novel and improved method and apparatus for searching is described. This searcher combines the ability to search multiple offsets of single pilots, such as those found in the IS-95 system, with the ability to search multiple pilots, such as those found in a GPS location determination system. Both types of searching can be done in a single architecture combining the parallel computation features of a matched filter with the flexibility of allowing a variable number of coherent accumulations and a variable number of non-coherent accumulations to be performed at high speed for a wide range of search hypotheses in a resource efficient manner. This invention allows for parallel use of the matched filter structure in a time-sliced manner to search multiple windows. In addition, the searcher allows for optional independent Walsh decovering for each search window. The time-sharing approach allows for optional frequency searching of any offset.

Abstract: A velocity estimate is determined from a received signal by counting the number of times a signal in one multipath crosses a predetermined threshold in a given amount of time. A signal is received and a single multipath is extracted from the received signal. Instantaneous envelope values of the extracted multipath are calculated. A plurality of the instantaneous envelope values are used to calculate a running RMS value. A level crossing threshold is determined using the running RMS value. The number of times the instantaneous envelope value crosses the level crossing threshold is counted. The number of level crossings is mapped to a velocity estimate.

Abstract: A digital signal processor (DSP) employs a variable-length instruction set. A portion of the variable-length instructions may be stored in adjacent locations within memory space with the beginning and ending of instructions occurring across memory word boundaries. The instructions may contain variable numbers of instruction fragments. Each instruction fragment causes a particular operation, or operations, to be performed allowing multiple operations during each clock cycle. The DSP includes multiple data buses, and in particular three data buses. The DSP may also use a register bank that has registers accessible by at least two processing units, allowing multiple operations to be performed on a particular set of data by the multiple processing units, without reading and writing the data to and from a memory. an instruction fetch unit that receives instructions of variable length stored in an instruction memory. An instruction memory may advantageously be separate from the three data memories.

Abstract: According to a disclosed embodiment, a receiver comprising a digital rotator in combination with a frequency error discriminator in a digital automatic frequency control loop is used to arrive at accurate digital values used to calibrate a local oscillation frequency. A frequency error in the oscillation frequency of a local frequency generation loop causes a change in the baseband input signal frequency. The change in the baseband input signal frequency related to the frequency error in the local frequency generation loop can be detected as a phase rotation by the frequency error discriminator. By using the digital automatic frequency control loop, the frequency error introduced by the local frequency generation is determined with accuracy. The frequency error and corresponding control bits are entered into a calibration table. The calibration table may be used to adjust the local oscillation frequency for temperature changes, pilot frequency searching, and quick paging.

Abstract: The present invention is a novel and improved method and circuit for digital signal processing. One aspect of the invention calls for the use of a variable length instruction set. A portion of the variable length instructions may be stored in adjacent locations within memory space with the beginning and ending of instructions occurring across memory word boundaries. Furthermore, additional aspects of the invention are realized by having instructions contain variable numbers of instruction fragments. Each instruction fragment causes a particular operation, or operations, to be performed allowing multiple operations during each clock cycle. Thus, multiple operations are performed during each clock cycle, reducing the total number of clock cycles necessary to perform a task. The exemplary DSP includes a set of three data buses over which data may be exchanged with a register bank and three data memories.

Abstract: The speech recognition training unit is modified to store digitized speech samples into a speech database that can be accessed at recognition time. The improved recognition unit comprises a noise analysis, modeling, and synthesis unit which continually analyzes the noise characteristics present in the audio environment and produces an estimated noise signal with similar characteristics. The recognition unit then constructs a noise-compensated template database by adding the estimated noise signal to each of the speech samples in the speech database and performing parameter determination on the resulting sums. This procedure accounts for the presence of noise in the recognition phase by retraining all the templates using an estimated noise signal with similar characteristics as the actual noise signal that corrupted the word to be recognized. This method improves the likelihood of a good template match, which increases the recognition accuracy.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method for performing position location on a subscriber unit in a terrestrial wireless telephone system using a set of satellites each transmitting a signal, the terrestrial wireless telephone system having base stations, including the steps of transmitting an aiding message from the base station to the subscriber unit, said aiding message containing information regarding a data boundary for each signal from the set of satellites, applying correlation codes to each signal yielding corresponding correlation data and accumulating said correlation data over an first interval preceding a corresponding data boundary yielding a first accumulation result, and a second interval following said corresponding data boundary yielding a second accumulation result.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method for performing position location comprising the steps of receiving signal samples, generating a coarse acquisition sequence, rotating the coarse acquisition sequence yielding a rotated coarse acquisition sequence, and applying the rotated coarse acquisition sequence to the signal samples at a set of time offsets yielding correlated output data.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method for performing position location on a subscriber unit in a terrestrial wireless telephone system using a set of satellites each transmitting a signal, the terrestrial wireless telephone system having base stations, including the steps of transmitting an aiding message from the base station to the subscriber unit, said aiding message containing information regarding a data boundary for each signal from the set of satellites, applying correlation codes to each signal yielding corresponding correlation data and accumulating said correlation data over an first interval preceding a corresponding data boundary yielding a first accumulation result, and a second interval following said corresponding data boundary yielding a second accumulation result.

Abstract: A novel and improved method for performing paging is described. In one embodiment of the invention a searcher is used to detect spread spectrum signals. Samples received RF signals are stored in a sample buffer. During standby mode, the samples are gathered during paging slots assigned to the mobile. A set of searches are performed on the samples, and if pilot signals are detected additional demodulation is performed to detect paging messages. The resulting set of demodulation data may be combined to increase detection. After a page message has been detected, additional demodulation resources may be activated to processes more complete page messages, or other information channels. In one embodiment of the invention, the searcher includes a demodulator to perform quick page detection without the use of finger elements to reduce idle mode power consumption.

Abstract: A novel and improved method and apparatus for providing an interface to a digital wireless telephone system compatible with standard analog wire line telephones and analog wire line fax machines is disclosed. During a telephone call, a fax detector monitors the incoming data for fax signals. If a fax is detected, the data processor switches from processing the data as if it were voice to processing it as fax In addition, the remote station is sent a signal notifying it to process the data as fax rather than voice. The fax detector operates by detecting the preamble of a V.21 message, present at the beginning of every fax call. Energy is measured in both frequencies of the BFSK signals. A decision is made by analyzing these energies and locating a specific pattern which repeats itself a sufficient number of times.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method of performing position location in a wireless subscriber unit having a local oscillator, including the steps of receiving a position location request, acquiring a timing signal when a sufficient period of time has elapsed since the local oscillator has been corrected and correcting said local oscillator using a correction signal based on said timing signal, substantially freezing the correction signal, performing a position location procedure using the local oscillator with the correction signal applied, and ending said position location procedure.

Abstract: A novel and improved method for performing paging is described. In one embodiment of the invention a searcher is used to detect spread spectrum signals. Samples received RF signals are stored in a sample buffer. During standby mode, the samples are gathered during paging slots assigned to the mobile. A set of searches are performed on the samples, and if pilot signals are detected additional demodulation is performed to detect paging messages. The resulting set of demodulation data may be combined to increase detection. After a page message has been detected, additional demodulation resources may be activated to processes more complete page messages, or other information channels. In one embodiment of the invention, the searcher includes a demodulator to perform quick page detection without the use of finger elements to reduce idle mode power consumption.

Abstract: A system for enhancing low frequency spectral content of a digitized signal which identifies a fundamental frequency component in the signal and selectively boosts signals within a predetermined range thereof. In the illustrative embodiment, the digitized signal is a frequency domain transformed speech signal. The invention amplifies the low frequency components of the speech signal. The speaker unique fundamental frequency of the speech is computed using pitch delay information and is thus dynamic from frame to frame and also speaker to speaker. This fundamental frequency defines the center point of a gain window which is applied to select frequency components. Only such fundamental frequency components which exhibit a large enough signal to noise ratio have the amplification function applied. Thus, this function can be applied directly following a noise suppression system which has knowledge of the signal quality in each frequency bin.

Abstract: A system for enhancing low frequency spectral content of a digitized signal which identifies a fundamental frequency component in the signal and selectively boosts signals within a predetermined range thereof. In the illustrative embodiment, the digitized signal is a frequency domain transformed speech signal. The invention amplifies the low frequency components of the speech signal. The speaker unique fundamental frequency of the speech is computed using pitch delay information and is thus dynamic from frame to frame and also speaker to speaker. This fundamental frequency defines the center point of a gain window which is applied to select frequency components. Only such fundamental frequency components which exhibit a large enough signal to noise ratio have the amplification function applied. Thus, this function can be applied directly following a noise suppression system which has knowledge of the signal quality in each frequency bin.

Abstract: A system and method for improving speech recognition accuracy in the presence of noise is provided. The speech recognition training unit is modified to store digitized speech samples into a speech database that can be accessed at recognition time. The improved recognition unit comprises a noise analysis, modeling, and synthesis unit which continually analyzes the noise characteristics present in the audio environment and produces an estimated noise signal with similar characteristics. The recognition unit then constructs a noise-compensated template database by adding the estimated noise signal to each of the speech samples in the speech database and performing parameter determination on the resulting sums. This procedure accounts for the presence of noise in the recognition phase by retraining all the templates using an estimated noise signal with similar characteristics as the actual noise signal that corrupted the word to be recognized.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. In one embodiment the invention comprises a method for performing position location in a subscriber unit in a CDMA wireless communications system having a base station, including the step of receiving a position location request during a communication, entering a position location mode, transmitting frames to the base station while performing a position location procedure, and returning to communications mode when said position location procedure has been completed.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method of performing position location in a wireless subscriber unit having a local oscillator, including the steps of receiving a position location request, acquiring a timing signal when a sufficient period of time has elapsed since the local oscillator has been corrected and correcting said local oscillator using a correction signal based on said timing signal, substantially freezing the correction signal, performing a position location procedure using the local oscillator with the correction signal applied, and ending said position location procedure.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment comprises a method for performing position location in a wireless communication system using a set of signals transmitted from a set of satellites including the steps of receiving signal samples, rotating an acquisition code by a first rotation amount yielding a rotated acquisition code, despreading said signal samples using rotated acquisition code yielding despread data, accumulating said despread data over a first duration yielding partially accumulated data, rotating said partially accumulated data by a second rotation amount yielding rotated data and accumulating said rotated data.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment comprises a method for performing position location using a set of signals transmitted from a set of satellites including the steps of storing coarse search data, performing a coarse search on said coarse search data for each satellite from said set of satellites, receiving fine search data, performing a set of fine searches on said fine search data, each fine search being performed on a different time segment of said fine search data, and reporting results.