Motorola Corporation

Tribeam Technologies, Inc.

Henry L Kazecki

Steven H Goode

James C Baker

Donald W Dennis

John W Diehl

Kevin Lynn Baum

James P Phillips

Bruce D Mueller

Michael D Kotzin

Thomas Casey Hill

Donald L Linder

Steve H Goode

David Erik Chevalier

A device () external to a wireless communication system infrastructure (), defines () a dispatch group having a dispatch group identifier and including a plurality of wireless units (). The device receives () a call for the dispatch group, the call including a message. The device establishes (), through the wireless communication system infrastructure, a group connection to the plurality of wireless units in response to receiving the call; and delivers () the message and the dispatch group identifier to the plurality of wireless units through the group connection.

Method and apparatus for providing dispatch calling through a wireless communication system infrastructure

An Infrared Data Association (IrDA) communication range () (e.g., 1 meter) of an IrDA compliant portable device () is increased to an extended range infrared communication (ERIC) range () (e.g., 2 to 40 meters) by extending a transmission range over an uplink channel () from the portable device () up to a base station () and by extending a transmission range over the downlink channel () from the base station () down to the portable device ().

Extended range infrared communication (ERIC) for an infrared associated (IrDA) compliant portable device

In a radiotelephone ( ), a channel estimator ( ) receives a time division multiple access (TDMA) information signal ( ) including a synchronous codeword ( ), formed of a first subset of seven sequential symbols ( ) followed by a second subset of seven sequential symbols ( ), followed by a data sequence ( ) formed of multiple sequential symbols. The channel estimator ( ) uses the first subset ( ) to train, via initializing ( ) and updating ( ), the channel estimator to stabilize the channel estimate. The channel estimator ( ) uses the second subset ( ) to train, via initializing ( ) and updating ( ), the predictor to improve the future accuracy of the channel estimate. The channel estimator ( ) then tracks ( ) the channel estimate over the data sequence ( ) by updating the channel estimator and the predictor over the data sequence ( ), without substantially affecting the stability of the channel estimate or the future accuracy of the channel estimate.

Channel estimator and method therefor

A voice recognition system (,) generates a variable rejection strictness as a function of at least one background noise level measured during training and noise signal measurements made during an input utterance made during recognition mode of operation. A word entrance penalty is assigned as a function of the variable rejection strictness.

Voice recognition system and method

A rectangular to phase converter (201) includes a first converter circuit (201B) which limits signals to a predetermined level. A phase selector (259) selects a relative phase from the limited signals. According to one aspect of the invention, input rectangular coordinate signals are mapped to the first quadrant in a first quadrant mapping circuit (201A) before the first quadrant signals are limited and the relative phase signal is returned to the original quadrant by an original quadrant mapping circuit (260).

Method and converter for converting rectangular signals to phase signals

A complex constellation point multiplier (600) multiplies a complex number by a point in a digital modulation constellation. The desired constellation point is mapped to a digital control word. The complex number is connected to multiplicand input nodes (610, 615) and the digital control word is connected to control input nodes (620, 623, 626). Via logic gates (602, 603, 605, 606, 607, 609), the control word controls switches (651-658) and simple arithmetic blocks, such as accumulators (650, 659), scaler blocks (663, 665), and negation blocks (643, 646), to generate an output complex number that is the product of the input complex number and the constellation point. This complex constellation point multiplier provides a lower size and lower power-consumption alternative to traditional complex number multipliers.

Complex constellation point multiplier

A diversity receiver (200) recovers clock information from different versions (301, 302) of a transmitted signal (106). The diversity receiver (200) receives the different versions (301, 302), converts the versions (301, 302) into samples (307, 317) via a common sampling clock (309). The receiver (200) then correlates the samples (307, 317) with like synchronization patterns and uses clock information from the received version (307 or 317) which gives the greatest correlation output signal (504, 506) for data detection in one of two detectors (323, 326). The choice of detectors (323, 326) is determined by the diversity receiver (200) by counting the total number of bit-differences output by detectors (323, 326) over a predetermined time period and comparing the total bit-differences with a number represented by a threshold signal (330).

Clock recovery method and apparatus in a diversity receiver

In a communications device, two coherent detection algorithms (102 and 103), one of which has a decision feedback equalizer (103), and a detector selection algorithm (104) are used to dynamically select a detector depending on whether delay spread distortion is present. First the correlation of the detector without the equalizer (102) is measured. If this correlation is greater than a predetermined threshold, the data from that detector (102) is used by the communications device. If the correlation is less than the threshold, the correlation of the detector with the equalizer (103) is measured. If this is less than the correlation of the detector without the equalizer (102), the data from the detector without the equalizer (102) is used, otherwise the data is taken from the equalizer (103). In any case, if the detector without the equalizer is used, the detector with the equalizer is turned off.

Method for channel adaptive detecting/equalizing

A complex signal correlator (106) and method therefor for correlating, at the multiple points in time, complex sampled (111) and reference (112) signals to produce a complex correlation signal (113). A relationship between the location of the reference signal (112) relative to the real and imaginary axes (301 and 302) is determined. The sampled signal (111) is processed responsive to the determined location, relative to the axes (301 and 302), of the reference signal (112) to produce real and imaginary processed components (210 and 211). The complex correlation signal (113) is produced responsive to adding (202-205) combinations of the real and imaginary processed components (210 and 211). Substituting adders (202-205) in the present invention for multipliers in the prior art complex signal correlators along with processing the sampled signal ( 111) significantly reduces the complexity of the complex signal correlator (106).

Complex signal correlator and method therefor

In a receiver an apparatus and method substantially reduces time dispersion and multipath distortion in a received signal. An equalizer (109), including taps having gain coefficients, produces an equalized signal (110) responsive to the received signal (107) and an adaptive process signal (137), wherein the gain coefficients are adjusted responsive to the adaptive process signal (137). A first mixer (111) mixes the equalized signal (110) and a reference carrier signal (115) to produce a recovered modulated signal (119). A detector (112) detects an estimate signal (129) responsive to the recovered modulated signal (119). An error signal generator (139) generates an error signal (141) responsive to a difference between the recovered modulated signal (119) and the estimate signal (129). A second mixer (147) mixes the error signal (141) and the reference carrier signal (115) to produce the adaptive process signal (137). In a preferred embodiment, a third mixer (153) mixes the estimate signal (129) and the reference carrier signal (115) to produce a feedback signal (135) for at least one tap. The present invention advantageously permits the equalizer (109) and the detector (112) to optimally perform their respective functions while coupled together to maximize the receiver's performance.

Apparatus and method for removing distortion in a received signal

The present invention presents an apparatus and method for recovering symbols in a data packet (101) transmitted to a receiver from a remote signal source (204) in a time-varying channel using multiple sampling points. In a digital cellular radiotelephone TDMA system, the receiver (202) performs a complex correlation on the desired slot sync word (DSSW) and the coded digital verification color code (CDVCC) in the data packet (101), and on the adjacent slot sync word (ASSW) in an adjacent data packet (102) to produce a first, second and third optimum sampling point, respectively. The data packet (101) is divided into four regions (A, B, C and D). The symbols in each region (A, B, C and D) are serially recovered using one or more of the multiple sampling points depending on the quality of the sampling point adjacent to each region (A, B, C and D).

Apparatus and method for recovering a time-varying signal using multiple

In a communications device, two coherent detection algorithms (102 and 103), one of which has a decision feedback equalizer (103), and a detector selection algorithm (104) are used to dynamically select a detector depending on whether delay spread distortion is present. First the correlation of the detector without the equalizer (102) is measured. If this correlation is greater than a predetermined threshold, the data from that detector (102) is used by the communications device. If the correlation is less than the threshold, the correlation of the detector with the equalizer (103) is measured. If this is less than the correlation of the detector without the equalizer (102), the data from the detector without the equalizer (102) is used, otherwise the data is taken from the equalizer (103).

Method for channel adaptive detecting/equalize

A differential quadrature PSK receiver (100) recovers serial data in a forward and reverse direction in time using a forward and reverse mode PLL (232) and decoder switch (108). The DQPSK receiver (100) is particularly useful for recovering a packet of serial data (Rx) having a time-varying signal level and a relatively long duration. Sync words in the packet (Rx) or adjacent packets (Ry) provide starting points from which the data is recovered. The direction in time of data recovery is dependent on the quality of the time-varying signal level in the packet (Rx).

Receiver for recovering data in a forward and reverse direction in time

An improved method and apparatus for demodulators for MSK signals. Demodulation of the MSK signals is performed at base-band other than at IF frequencies. A digital signal processor is preferably used.

DSP-based GMSK coherent detector

The .pi./4-QPSK coherent detector of the present invention has a vector input and an output comprising recovered data in bit pair form. The .pi./4-QPSK coherent detector recovers bursts of data, in a TDMA system, that has been encoded in an amplitude modulated vector's phase angle. The .pi./4-QPSK coherent detector detects the .pi./4-QPSK constellation of the incoming modulated signal and outputs the recovered data stream.

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Arlington Heights, IL, United States of America

Henry L Kazecki