Qualcomm Incorporated

University of California

Wei Xiong

David Jonathan Julian

Chong U Lee

Amal Ekbal

Pavel Monat

Lawrence E Larson

A receiver in an OFDM communication system includes a power detector and a gain controller. The power detector detects for total received power of a received OFDM signal, e.g., by computing the power of the data samples from an ADC and averaging the power. The gain controller adjusts the gain of the receiver in discrete gain steps and in one direction, e.g., from the lowest gain state to the highest gain state, based on the detected total received power. The gain controller initializes the receiver to the lowest gain state. Thereafter, the gain controller detects for low total received power, e.g., by comparing the detected total received power against a predetermined threshold. The gain controller transitions to a higher gain state if low total received power is detected and maintains the current gain state otherwise.

Gain control for a receiver in a multi-carrier communication system

Phase of an output signal is based on comparison of an oscillating signal with an adjustable threshold. Here, adjustment of the threshold results in a corresponding adjustment of the phase of the output signal. For example, the adjustable threshold may comprise an adjustable bias signal for a transistor circuit whereby the oscillating signal is provided as an input to the transistor circuit and the output of the transistor circuit provides the output signal. In some aspects these phase adjustment techniques may be employed to provide one or more tunable multiphase clocks.

Signal generator with adjustable phase

Frequency of an oscillating signal is temporarily adjusted to adjust frequency and/or phase of an output signal. For example, the frequency of the oscillating signal may be adjusted for a very short period of time to adjust the phase of the output signal. In addition, the frequency of the oscillating signal may be temporarily adjusted in a repeated manner to adjust the effective frequency of the output signal. In some aspects the frequency of the oscillating signal is adjusted by reconfiguration of reactive circuits associated with an oscillator circuit.

Signal generator with adjustable frequency

Frequency and phase of an output signal is adjusted to track an input signal. A control signal is adjusted to control a frequency of an oscillating signal from which the output signal is derived. In some aspects the frequency of the oscillating signal is adjusted by reconfiguration of reactive circuits coupled to an oscillator circuit. Phase of the output signal may be adjusted based on comparison of the oscillating signal with an adjustable threshold. For example, the adjustable threshold may comprise an adjustable bias signal for a transistor circuit whereby the oscillating signal is provided as an input to the transistor circuit and the output of the transistor circuit provides the output signal.

Signal generator with signal tracking

A discrete low-noise amplifier designed to operate in a mobile wireless environment uses two cascaded GaAs FETs to achieve 25 dB gain and 0.9 dB noise figure at 2.5 GHz. Active bias control circuitry responsive to monitored amplifier output power automatically and continuously adjusts the drain-source currents, and the load lines, of the cascaded FETs to (i) maintain power consumption at 33 milliwatts in nominal small-signal conditions, and to (ii) provide an elevated input third-order intermodulation intercept point (IP3) and a reduced noise figure during the presence of jamming. A 15 dB improvement in the input IP3 is achieved in large-signal operation. Amplifier operation is supported by an a.c. power detector of enhanced sensitivity and responsiveness because of un-grounded operation.

S-band low-noise amplifier with self-adjusting bias for improved power consumption and dynamic range in a mobile environment

Methods and apparatus for digital jammer detection. In an aspect, a method is provided for detecting a jammer in a received waveform. The method includes filtering the received waveform to produce a filtered waveform and subtracting the filtered waveform from the received waveform to produce a difference waveform. The method also includes determining a power differential associated with the difference waveform, and detecting the jammer if the power differential exceeds a selected threshold. In an aspect, an apparatus is provided that includes a filter configured to filter the received waveform to produce a filtered waveform and combining logic configured to subtract the filtered waveform from the received waveform to produce a difference waveform. The apparatus also includes power determination logic configured to determine a power differential associated with the difference waveform, and decision logic configured to detect the jammer if the power differential exceeds a selected threshold.

Methods and apparatus for digital jammer detection

A communication device having a structure that utilizes a minimum number of switches to bypass a power amplifier in the communication device is disclosed. The communication device takes advantage of the half-duplex operation of the RF transmitter and receiver in the communication device to minimize the number of switches required to bypass a power amplifier in the communication device.

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San Diego, CA, United States of America

Wei Xiong