Qualcomm Incorporated

University of California

Prasad S Gudem

Li Liu

Jose Cabanillas

Li-chung Chang

Steven C Ciccarelli

Soon-Seng Lau

Junxiong Deng

Namsoo Kim

Sai Kwok

David Jonathan Julian

Brian Clarke Banister

Joseph Patrick Burke

Gurkanwal Singh Sahota

Roberto Rimini

Bhushan Shanti Asuri

Vladimir Aparin

Yang Xu

Lawrence E Larson

Shrenik Patel

Yang Sun

Vinod Panikkath

Sumit Verma

Robert Keith Douglas

Gang Zhang

Brian George

Anup Savla

Pavel Monat

Wingching Vincent Leung

Arun Raghupathy

Alvin Siu-Chung Ng

Chunchung Chan

Ken Tsz Kin Mok

Cristian Marcu

Vincent Leung

Peter C Gazzerro

David Love

Lawrence E Larsen

Peter D Heldmann

Saraswathi Palakurty

Li-Chung Chang

Steven C c/o Qualcomm Incorporated Ciccarelli

Gurkanwal Kamal Sahota

Sai Chong Kwok

Although the duplexer in a full-duplex transceiver circuit may only be guaranteed by the duplexer manufacturer to have a transmit band rejection from its TX port to its RX port of a certain amount, and may only be guaranteed to have a receive band rejection of another amount, the actual transmit band rejection and the actual receive band rejection of a particular instance of the duplexer may be better than specified. Rather than consuming excess power in the receiver and/or transmitter in order to meet performance requirements assuming the duplexer only performs as well as specified, the duplexer's in-circuit performance is measured as part of a transmitter-to-receiver isolation determination. Transmitter and/or receiver power settings are reduced where possible to take advantage of the measured better-than-specified in-circuit duplexer performance, while still meeting transceiver performance requirements. Power settings are not changed during normal transmit and receive mode operation.

Reducing power consumption by taking advantage of superior in-circuit duplexer performance

Disclosed are circuits, techniques and methods for implementing a process of selectively bypassing a duplexer in a transmission path. In a particular embodiment, a receiver and a transmitter are coupled to a shared antenna through a duplexer. The duplexer may be selectively bypassed under certain conditions while the receiver is disabled and/or powered off.

Duplexer bypass

Techniques for controlling operation of control loops in a receiver are described. The operation of at least one control loop is modified in conjunction with a change in operating state, which may correspond to a change in linearity state, gain state, operating frequency, antenna configuration, etc. A change in linearity state may occur when jammers are detected and may cause bias current of analog circuit blocks to be adjusted. The at least one control loop to be modified may include a DC loop, an AGC loop, etc. The operation of a control loop may be modified by disabling the control loop or changing its time constant prior to changing operating state, waiting a predetermined amount of time to allow the receiver to settle, and enabling the control loop or restoring its time constant after waiting the predetermined amount of time.

Techniques for controlling operation of control loops in a receiver

Reducing power consumption by in-circuit measurement of receive band attenuation and/or noise

Certain aspects of the present disclosure propose an adaptive joint linear and non-linear digital filter that can adaptively estimate and reconstruct cascaded effects of linear and non-linear self-jamming distortions introduced by non-linearities in the transmit and/or receive chains. The proposed digital filter may be used to cancel second-order inter-modulation distortion (IM2) generated in the receive chain and/or harmonic distortion generated in the transmit chain, as well as other distortions introduced by the transmit/and or receive chains.

Joint linear and non-linear cancellation of transmit self-jamming interference

Techniques for detecting jammers in a received signal are described. A jammer detector includes a jammer filter for attenuating transmit signals leaked into the receive path, a pulse generator for converting the interference signals into discrete-level pulses, and a pulse processor for determining the presence of jammers in the discrete-level pulses. In an exemplary embodiment, the pulse processor is configured to further discriminate among close-in jammers that are close to the desired receive frequency, far-away jammers, and jammers arising from the transmit signals leaked into the receive path. In another exemplary embodiment, hysteresis is provided in the pulse generator to enable the generation of reliable pulses. Further aspects include configuring the jammer detector for operation in a plurality of frequency bands and/or according to a plurality of communications standards.

Interference detection apparatus and method

Techniques for generating local oscillator (LO) signals are described. In one design, an apparatus may include a deskew circuit and a divider circuit. The deskew circuit may receive a differential input oscillator signal having timing skew and provide a differential output oscillator signal having reduced timing skew. The differential input oscillator signal may include first and second input oscillator signals, and the differential output oscillator signal may include first and second output oscillator signals. In one design, the deskew circuit may include first and second variable delay circuits that receive the first and second input oscillator signals, respectively, and provide the first and second output oscillator signals, respectively. Each output oscillator signal may have an adjustable delay selected to reduce timing skew. The divider circuit may divide the differential output oscillator signal in frequency and provide differential I and Q divided signals, which may be used to generate LO signals.

LO generation with deskewed input oscillator signal

A receiver includes a low noise amplifier (LNA) and multiple pairs of mixers. The LNA receives and amplifies an LNA input signal and provides at least one LNA output signal. Each pair of mixers downconverts one of the at least one LNA output signal when enabled. Each pair of mixers may be selectively enabled or disabled, e.g., based on a mode selected from among multiple modes. In one design, the LNA includes multiple load sections coupled in parallel. Each load section may be selectively enabled or disabled, e.g., based on the selected mode. In one design, first and second pairs of mixers and first and second load sections may be enabled for a high linearity mode. The first pair of mixers and the first load section may be enabled and the second pair of mixers and the second load section may be disabled for a low linearity mode.

High linearity low noise receiver with load switching

An integrated circuit for achieving power reduction in a transceiver may include a jammer detector that determines an interference level corresponding to a received signal, and a transmit power detector that determines a required transmit power level for a transmitted signal. The integrated circuit may also include at least one of the following: a process monitor that determines process corners of components within the receiver and/or the transmitter, and a temperature monitor that determines a temperature of the receiver and/or the transmitter. The integrated circuit may also include a state machine. The state machine may transition the receiver from a high linearity mode to a low linearity mode if a set of operating conditions is satisfied. Similarly, the state machine may transition the transmitter from a high power mode to a low power mode if a set of operating conditions is satisfied.

Methods and apparatus for power reduction in a transceiver

Techniques for performing transmit (TX) leakage cancellation are described. A receiver includes a low noise amplifier (LNA) and a TX leakage canceller. The LNA amplifies a receiver input signal and provides an amplified signal. The TX leakage canceller includes a downconverter, a notch filter, and an upconverter. The downconverter downconverts a canceller input signal (e.g., obtained from the LNA output) with a first LO signal at a transmit frequency and provides a downconverted signal. The notch filter filters the downconverted signal to pass an undesired signal (e.g., a TX leakage signal) and attenuate a jammer and a desired signal in the canceller input signal. The upconverter upconverts the filtered signal with a second LO signal at the transmit frequency and provides a feedback signal. The feedback signal is subtracted at the input or output of the LNA to cancel the undesired signal.

High-linearity receiver with transmit leakage cancellation

Sub-carrier selection methods and receiver architectures for receiving an Orthogonal Frequency Division Multiplexing band sensed by a plurality of antennas (-). Filtering is applied to separately pass portions of the predetermined Orthogonal Division Multiplexing frequency band. Each separate portion encompasses one or more sub-bands of the predetermined Orthogonal Division Multiplexing frequency band. For each of the separate portions of the predetermined Orthogonal Division Multiplexing frequency band, the signal received from one of the plurality of antennas is selected. The selected signals for each separate portion are then combined in the time (analog) domain.

Multiple sub-carrier selection diversity architecture and method for wireless OFDM

A receiver includes a jammer detector configured to detect the presence or the absence of jamming in a communication signal within a gain state. The receiver further includes an amplifier configured to amplify the communication signal in a high linearity receiving mode or a low linearity receiving mode, wherein the high linearity receiving mode corresponds with a lower gain for the gain state in the amplifier relative to that of the low linearity receiving mode. In addition, the receiver includes a processing unit coupled to the jammer detector, the processing unit being configured to control the amplifier to amplify the communication signal in either the high linearity receiving mode or the low linearity receiving mode, based on the output of the jammer detector detecting the presence or the absence of jamming in the communication signal. A method is also provided for processing a communication signal in a receiver.

Reconfigurable high linearity low noise figure receiver requiring no interstage saw filter

A communication channel has a highly linear switched current mixer that incorporates passive filtering (e.g., low pass, notch) for improved transmitting (Tx) and receiving (Rx) with adding external filtering components. A high IIP(input referenced second order intercept point) of the receiver at the Tx offset is essential to avoid corrupting the system's sensitivity performance, and a high triple beat (TB) is required to avoid sensitivity degradation due to transmitter leakage. Thanks to the embedded filtering in the mixer and the active post-distortion (APD) method in a low noise amplifier (LNA), the required high linearity is achieved with low noise figure and power consumption, overcoming transmitter power leakage without the use of a SAW (surface acoustic wave) filter.

Highly linear embedded filtering passive mixer

An apparatus, which may be configured as a receiver or transceiver, includes a plurality of super regenerative (SR) amplifiers coupled in parallel, wherein the SR amplifiers are tuned to distinct frequency bands, respectively. The apparatus may further include isolation amplifiers at the respective inputs and outputs of the SR amplifiers to prevent injection locking and reduce power leakage. The apparatus may include a circuit to reduce or substantially eliminate in-band jamming signals. The apparatus may form at least part of a wireless communications device adapted to receive signals from other wireless communications devices, adapted to transmit signal to other wireless communications devices, and adapted to both transmit and receive signals to and from other wireless communications devices.

Super regenerative (SR) apparatus having plurality of parallel SR amplifiers tuned to distinct frequencies

Active circuits with active loads linearized via distortion cancellation are described. In one design, an apparatus includes a first stage and a load stage. For an amplifier, the first stage amplifies an input signal and provides an output signal having a larger signal level. For a mixer, the first stage mixes an input signal with an LO signal and provides an output signal. The load stage provides an active load for the first stage and is linearized by canceling distortion generated by the active load. In one design, the load stage includes a first transistor that provides the active load and generates distortion due to its nonlinearity. The load stage further includes at least one transistor that generates a replica of the distortion from the first transistor. The distortion replica is used to cancel the distortion from the first transistor. The first stage may also be linearized with distortion cancellation.

Active circuits with load linearization

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San Diego, CA, United States of America

Prasad S Gudem