International Mobile Machines Corporation

Interdigital Technology Corporation

Wi-Lan Inc.

Other

International Mobile Machine Corporation

Karle J Johnson

David N Critchlow

Graham M Avis

Moshe Yehushua

Sandra J Earlam

Bruce A Smetana

Gregory L Westling

Eric Paneth

Wade Lyle Heimbigner

George Alan Wiley

Kenneth L Stanwood

Yair Bourlas

Peter Graumann

Brian David Petry

Kripps Asirvatham

Doraid Y Sadiq

Thomas E Fletcher

Gregory T Saffee

Wendeline Ruth Avis

Graham N Avis

An error management system and process can be used to identify an erroneous data packet in a data stream. In response to identifying the erroneous data packet, a subsequent valid data packet is located in the data stream. In one embodiment, a plurality of candidate locations of header checksum windows are searched and checked for a valid checksum. Multiple integrity checks of multiple header checksums can be used to reduce the probability of a false positive integrity check. In another embodiment, one or more information data fields can used for determining packet integrity by determining if the fields contain valid information bits.

System and process for packet delineation

A FIR chip is used in a wireless subscriber unit. The subscriber unit includes a processor for transcoding an input signal to provide digital input symbols. A received output signal is demodulated. Digital output symbols are synthesized from the demodulated output signal processor and filtered digital input symbols are provided. An internal address decoder decodes to allow the processor to access internal functions of the FIR chip. A control and status register allows the processor to read the status of and control the internal functions of the FIR chip. A FIR filter filters the digital input symbols. A transmit timer controls timing which allows the processor to control the FIR filter. A receive timer generates timing signals for timing transcoding operations and synthesizing operations connected to the processor.

FIR chip for use in a wireless subscriber unit

A subscriber unit has a processor. The processor provides an output phase signal corresponding to a selected output digital frequency. A tuning register buffers the phase signal. A lookup table has two sets of predefined stored values pertaining to the amplitude of a signal for a single quadrant. The predefined stored values comprise coarse angle approximations and fine angle approximations. A sine and cosine generator receives the phase signal and generates sine and cosine waveforms utilizing amplitude values obtained from the lookup table. The phase signal includes phase data and specifies the quadrant and the algebraic sign of the phase data. The sine and cosine generator accessing the lookup table differently depending upon the quadrant and sine of the phase data, such that the lookup table provides an amplitude value from the sets of predefined stored values based on the phase data. A modulator combines the sine and cosine waveforms to produce the selected output digital frequency and modulates digital frequency.

Subscriber unit producing a modulated digital frequency

The present invention is a method and system for processing communication signals in a wireless telecommunication system having at least two subscriber units. The subscriber units communicate with each other through a selected band of radio frequencies over a plurality of radio frequency channels. The system generates a fixed based radio frequency signal and a digital intermediate frequency signal. The fixed based radio frequency signal and the digital intermediate frequency signal are then combined to produce a carrier signal which is communicated between the at least two subscribers.

Digital synthesizer

A subscriber unit for wireless communication with a base station in a wireless subscriber communication system includes a FIR chip, a DIF (digital intermediate frequency) chip, a single prccessor chip and a radio. The processor chip transcodes a digital voice input signal to provide digital input symbols; demodulates an output signal received from the base station to provide digital output symbols; and synthesizes a digital voice output signal from the digital output symbols. The FIR chip FIR filters the digital input symbols and generates timing signals for timing the transcoding and synthesizing operations in the processor chip. The DIF chip digitally synthesizes a digital intermediate frequency signal by direct digital synthesis (DDS) and modulates the digital intermediate frequency signal with the filtered input symbols to provide a modulated intermediate frequency input signal. The radio further processes the modulated input signal for transmission to the base station.

A subscriber unit for wireless communication with a base station in a wireless subscriber communication system includes a FIR chip, a DIF (digital intermediate frequency) chip, a single processor chip and a radio. The processor chip transcodes a digital voice input signal to provide digital input symbols; demodulates an output signal received from the base station to provide digital output symbols; and synthesizes a digital voice output signal from the digital output symbols. The FIR chip FIR filters the digital input symbols and generates timing signals for timing the transcoding and synthesizing operations in the processor chip. The DIF chip digitally synthesizes a digital intermediate frequency signal by direct digital synthesis (DDS) and modulates the digital intermediate frequency signal with the filtered input symbols to provide a modulated intermediate frequency input signal. The radio further processes the modulated input signal for transmission to the base station.

Subscriber unit for wireless digital subscriber communication system

A subscriber unit for a wireless digital telephone system is disclosed. An equalizer for receiving I and Q samples is disclosed which is in the form. The I and Q samples are complex sample pairs provided at a frequency. The equalizer receives a training signal in the form of complex I and Q sample pairs. A training signal is affected by undesirable characteristics that might be present in the I and Q samples. A comparator compares the actual input training signal with the desired output to obtain a set of weighting coefficients for the equalizer to produce the desired output. A frequency correction circuit provides a corrected frequency signal for the frequency of the sample pairs from the weighting coefficients.

Subscriber unit for wireless digital telephone system

A digital frequency synthesizer for use in a subscriber unit of a wireless digital communication system includes a processor, for providing an output phase signal corresponding to a selected output digital frequency a storage device having predefined stored values pertaining to the amplitude of a signal for a single quadrant, and a signal generator which receives the phase signal and generates sine and cosine waveforms utilizing amplitude values obtained from the lookup tables. The signal generator accesses the storage device differently depending upon the quadrant and sign of the phase data such that the storage device provides an amplitude value from said set of values based upon the phase data.

Direct digital frequency synthesizer for use in a subscriber unit of a

In a wireless digital telephone system, a circuit for determining in a subscriber unit whether a particular RF channel is of the type designated by the base station to be either a control channel or a voice channel and for determining whether the channel is in the transmit or receive mode; the circuit utilizing the duration of an AM hole to determine the type of the channel and utilizing a unique word for determining the mode.

A digital wireless subscriber telephone unit for wireless communication with a base station. An IF is used within the subscriber unit and base station which is combined with a carrier signal generated by a synthesizer for RF transmission between stations. In intervals between actuation of the system, a training mode is used wherein a known training signal is compared with a known values to produce correction coefficients to compensate for undesirable variations in timing and/or frequency, these constants being stored for use in correcting actual received signals. During demodulation, the modulated digital signals are fed to the modem processor in the form of time multiplexed I and Q samples and are demultiplexed. The demultiplexed I and Q samples are fed to an equalizer and frequency correction circuit for minimization of errors for production of a frequency correction signal based upon the correction coefficients which is used to correct any errors in the timing and frequency of the system.

Automatic adaptive equalizer

A frequency synthesizer that generates two output signals at a set frequency apart from each other and in synchronization with each other. The output frequency is selected by a microprocessor and the set frequency difference between the two output signals is determined by a frequency divider and a voltage controlled oscillator.

Growing community of inventors

Carlsbad, CA, United States of America

Karle J Johnson