Described is a communication system including mobile communication devices. In the described system, the mobile devices may be wrist-worn watches such as are in common use today, except that the watches are specially configured to receive data in a “broadcast” mode and transmit and/or receive data in a “localcast” mode. The localcast mode includes the ability to transmit and receive data in a peer-to-peer fashion, allowing mobile devices to communicate directly with each other. The ability to combine two of these communication modes in a small, integrated and hence inexpensive and low-power package provides many advantages over existing personal communication device solutions.

System and apparatus for performing broadcast and localcast communications

The present invention provides high power linear amplification of an amplitude and/or phase modulated signal using multiple saturated (or if desired, unsaturated) amplifiers (4) driven by an appropriate set of switched (5), and/or phase modulated (6) constant amplitude signals derived from the input signal. The present invention combines three amplitude reconstruction techniques and implements the amplitude reconstruction modulator (11) digitally.

Amplification using amplitude reconstruction of amplitude and/or angle modulated carrier

Frequency translation and applications of same are described herein, including wireless local area network (WLAN) applications such as IEEE Standard 802.11 WLANs. Such applications include, but are not limited to, frequency down-conversion, frequency up-conversion, enhanced signal reception, unified down-conversion and filtering, and combinations and applications of same.

Wireless local area network (WLAN) technology and applications including techniques of universal frequency translation

A transceiver for transmitting and receiving signals includes a transmitter operative to up-convert baseband signals from a baseband frequency into RF signals at a radio frequency (RF) frequency and output the RF signals, a receiver operative to receive RF signals and down-convert the RF signals into baseband signals having the baseband frequency, and a plurality of calibration paths coupling the transmitter to the receiver. Any of the calibration paths can be selected to be active when calibrating components of the transceiver. Tunable components can use calibration information to optimize transceiver performance.

Direct-conversion transceiver enabling digital calibration

A system for linearly transmitting an amplified output signal using predistortion is disclosed. The system uses a straight inverse modeling scheme with orthogonal predictor variables to more easily and accurately determine the inverse of the distortion caused by a power amplifier of a RF transmitter. The direct inverse modeling scheme of the present invention indexes the LUT using the modulated input signals instead of the potentially noisier output signals, which helps to increase the accuracy of the predistortion. The predistorter system stores complex coefficients in the LUT, which are then used as the tap weights of a non-linear digital filter implementing the predistorter. Finally, the trainer uses a modified version of the power amplifier output signal which results in better predistortion performance. The modified power amplifier output signal has the in-band distortion removed from the power amplifier output signal.

Predistortion in a linear transmitter using orthogonal kernels

A linear transmitter (101) using predistortion includes a modulator (103), a predistorter (107), a digital quadrature modulator (111), an upconverter (113), a power amplifier (115), and an antenna (117). In addition, the transmitter (101) has a feedback loop including a coupler (119), a downconverter (123), a digital quadrature demodulator (125), and a trainer (131). The digital data to be transmitted is provided into the modulator (103), which converts the digital data into in-phase and quadrature component signals. The in-phase and quadrature component signals are then provided to the predistorter (107), which "predistorts" the component signals prior to amplification. The digital quadrature modulator (111) converts the component signals into a single analog signal. The upconverter (113) upconverts this signal from the predistorter (107) into the desired frequency of transmission, which is provided to the power amplifier (115) and the antenna (117) for amplification and broadcast. The coupler (119) provides a portion of the amplified signal to the analog downconverter (123), which lowers the frequency of this signal to a range that is easily processed. The signal is then provided to the digital quadrature demodulator (125), which outputs the in-phase and quadrature component signals of the signal. These in-phase and quadrature component signals are provided to the trainer (131) which analyzes them with the output signals from the modulator. The trainer (131) compares these signals and updates the predistorter (107) so that the digital quadrature demodulator (125) output signals are substantially equivalent to the modulator (103) output signals.

Linear transmitter using predistortion

A method and apparatus for estimating a satellite signal parameter in a satellite positioning system receiver is described. In an example, a plurality of correlation results between a satellite signal and a reference signal is generated in response to a command from a processor. At least one satellite signal parameter is estimated from the plurality of correlation results using a co-processor integrated within the satellite positioning system receiver. The at least one satellite signal parameter is then provided to the processor.

Method and apparatus for performing signal correlation using historical correlation data

A method and apparatus for processing satellite positioning system signals at a mobile receiver is described. In one example, first bit-transitions within satellite navigation data transmitted by at least one satellite are estimated at the mobile receiver. A bit pattern is generated that includes a known preamble and an extended preamble. The extended preamble includes expected data bits within the satellite navigation data. The first bit-transitions are compared with second bit-transitions of the bit pattern to generate match data.

Method and apparatus for processing satellite positioning system signals to obtain time information

A method and apparatus for performing frequency analysis of sub-epoch correlations to estimate an unknown frequency of a received signal is provided. The method includes forming a sequence of correlation values from a plurality of correlations performed over a period less than a repeating period of a code, and analyzing the sequence of correlation values to estimate the frequency that is used to receive a signal comprising the code.

Method and Apparatus for Performing Frequency Synchronization

Method and apparatus for decoding a bitstream of navigation data broadcast by a satellite positioning system satellite is described. In one example, a portion of a subframe in the navigation data for each of a plurality of occurrences of the subframe in the bitstream is obtained at a satellite signal receiver to produce a respective plurality of subframe portions. The subframe portions are then combined to recover the subframe. The subframe portions may be processed to maintain a constant polarity by comparing a common sequence of data bits among at least two of the subframe portions to identify a mismatch in polarity.

Emre Tapucu

Papers

Linear transmitter using predistortion

Method and apparatus for performing signal correlation using historical correlation data

Method and apparatus for processing satellite positioning system signals to obtain time information

Method and Apparatus for Performing Frequency Synchronization

Method and apparatus for decoding satellite navigation data from a satellite positioning system