Marvell International Limited

Marvellworld Trade Ltd.

Marvell Asia Pte., Ltd.

Sergey Timofeev

Hongyuan Zhang

Atul Salhotra

Sudhir Srinivasa

Rohit U Nabar

Mao Yu

Swaroop Venkatesh

Lance Nagamine

Kedar Shirali

Harish Ramamurthy

Xiayu Zheng

Brian Bosso

Li Lin

Daxiao Yu

Chor-Teck Law

Srinivasa H Garlapati

Arnab Kumar Mitra

Rui Cao

Ming Lin

Tsunglun Yu

Hua Mu

Hemabh Shekhar

Srinivas Pinagapany

Ping Gao

A radiofrequency system includes a plurality of transceivers providing a plurality of channels, and circuitry configured to perform off-channel functions. A first subset of channels performs radiofrequency communication functions, and a second subset of channels provides signals for the off-channel functions. The first subset of channels may be provided by a first subset of transceivers, and the second subset of channels may be provided by a second subset of transceivers. A spectrum sensing unit may select between the first subset of transceivers and the second subset of transceivers. The circuitry configured to perform the off-channel functions may use the second subset of the plurality of channels to perform neighborhood discovery. The circuitry configured to perform the off-channel functions may scan available communications channels for interference, storing identifications of interference-free channels, and, upon detection of interference on a channel in use, may select one of the interference-free channels.

Multi-channel RF system with off-channel scanning

A communication device generates: i) a physical layer (PHY) preamble of a PHY protocol data unit (PPDU), ii) a first portion of a PHY data payload of the PPDU, and iii) a second portion of the PHY data payload. The PHY preamble includes a first training field, and one or more second training fields. The first portion of the PHY data payload and the second portion of the PHY data payload include a plurality of first orthogonal frequency division multiplexing (OFDM) symbols. Each of multiple first OFDM symbols has a first duration. The communication device generates a PHY midamble of the PPDU to be included between the first and second portions of the PHY data payload. The PHY midamble includes one or more third training fields, each including a respective second OFDM symbol having a second duration shorter than the first duration.

Packets with midambles having compressed OFDM symbols

The present disclosure describes apparatuses and methods for a configurable wireless communication chip. In some aspects, a wireless communication chip includes multiple radio paths and is capable of operating in a first communication mode that supports communication in non-contiguous segments of bandwidth and a second communication mode that does not support communication in non-contiguous segments of bandwidth. Based on a hardware configuration external to the wireless communication chip, the radio paths can be configured to operate in the first communication mode or the second communication mode. In some cases, the hardware configuration external to the wireless communication chip includes fewer antennas or amplifier paths than radio paths of the chip, such as due to cost or form-factor considerations. In such cases, the wireless communication chip can operate in the second communication mode to implement advanced communication techniques with reduced hardware, enabling flexibility to design lower cost or smaller devices.

Apparatus and methods for a configurable wireless communication chip

A method of calibrating analog transceiver delay includes generating a signal in a portion of a first device to arrive at a first known time at analog transmit circuitry of the first device, transmitting the signal from the analog transmit circuitry of the first device, receiving the transmitted signal, and deriving transceiver delay from the received signal. The transmitting may be performed via a closed loop to analog receiver circuitry of the first device, detecting the signal at a second known time at an output of the analog receiver circuitry of the first device. The transmitting also may be performed wirelessly to receiver circuitry of a second device placed at a predetermined distance from the first device, detecting the received signal at a second known time at the receiver circuitry of the second device. Transceiver delay can be determined from transit time and apportioned between transmit delay and receive delay.

Method and apparatus for calibrating transmit delay and receive delay

In accordance with embodiments of the present disclosure there is provided a method for carrier sensing. The method includes receiving, at a wireless receiver, an input signal, and generating, based on a sampling period, a plurality of data samples from the input signal. The method further includes periodically combining a first data sample from the plurality of data samples with a second data sample that is one or more sampling periods before the first data sample to generate a combined data sample. The method further includes generating an auto-correlated output for carrier sensing based on the combined data sample. The auto-correlated output is provided to generate an estimate of phase difference between the first sample and the second sample for the periodic combining.

Systems and methods for carrier sensing in wireless communication systems

Systems and methods for removing DC offset from a signal are provided. A radio frequency signal is received at a receiver. The radio frequency signal is converted into a digital signal including a periodic component with a period. A carrier frequency offset is removed from the digital signal to generate a frequency-shifted digital signal. The frequency-shifted digital signal is filtered to remove a DC offset in the digital signal. The filtering includes applying a moving average filter matched to the period to remove the periodic component from the frequency-shifted digital signal. The moving average filter generates a set of average values based on the frequency-shifted digital signal. The filtering also includes taking a difference between consecutive values of the set of average values to determine the DC offset, where the DC offset is introduced at the receiver.

Systems and methods for DC offset correction

Devices and methods capable of addressing filter responses are disclosed. For example, a method for compensating a first low-pass filter and a second low-pass filter is disclosed. The method includes injecting a reference tone fand a cutoff tone finto the first low-pass filter, and measuring respective filter responses of the reference tone fand the cutoff tone fwhile changing capacitor codes that control a cutoff frequency of the first low-pass filter until a first capacitor code Iis determined that most accurately causes the first low-pass filter to utilize a desired cutoff frequency f, performing a similar operation for the second low-pass filter until a second capacitor code Qis determined, and calibrating for mismatch between the first low-pass filter and the second low-pass filter.

Methods and systems for calibrating an analog filter

Systems, methods, and other embodiments associated with unified control of timing recovery and packet processing are described. According to one embodiment, a method for performing unified control of timing recovery and packet processing is provided. The method includes sampling a received signal according to an ADC timing signal to produce a sequence of samples. The received signal corresponds to a packet and was transmitted according to a transmit timing signal. The method includes determining a phase offset between the ADC timing signal and the transmit timing signal and identifying, based, at least in part, on the phase offset, a data portion of the sequence of samples that contains data encoded in the received signal. A re-generated sample sequence that adjusts the data portion based on the phase offset is calculated.

Unified control for digital timing recovery and packet processing

A method for transmitting a data packet includes prepending to the digital contents of the data packet a preamble including a first preamble field having a plurality of repetitions of a sequence. The method also includes determining according to a specified communication protocol a first transmission power level for the data packet and determining according to the specified communication protocol and the first preamble field an unadjusted transmission power level for the first preamble field. The method further includes determining the presence of one or more power-boost characteristics of the data packet or of an intended receiving client, transmitting the first preamble field at a first adjusted transmission power level if one or more power-boost characteristics are determined to be present, and transmitting a remainder of the data packet at the first transmission power level for the data packet.

Method and apparatus for detecting a packet in a WLAN system

A bias current utilized in a unit of a radio frequency (RF) receiver device of a network interface is controlled. A modulation scheme utilized in a packet being received by the network interface is determined. It is determined, based on the determined modulation scheme, whether a level of the bias current should be changed. When it is determined that the level of the bias current should be changed, a control signal to change the level of the bias current is generated.

Bias current control for a radio frequency unit of a wireless network interface

A radio frequency transmitting system which includes first and second amplifiers, a power detector, and a calibration module. The first amplifier amplifies an input signal to generate an amplified signal in accordance with a programmable gain. The second amplifier transmits an output signal based on the amplified signal. The output signal is transmitted at a particular power by the second amplifier. The power detector measures the particular power at which the output signal is transmitted by the second amplifier. The calibration module adjusts the programmable gain of the first amplifier by a calibration offset so that the particular power measurement matches a predetermined power. The calibration module includes offset generation modules that each generate a respective calibration offset candidate based on the particular power measurement. The calibration module also includes a selection module that selects, based on the predetermined power, one of the calibration offset candidates as the calibration offset.

Closed-loop power control using multiple feedback loops

In a method for detecting a synchronization field in an orthogonal frequency division multiplexing (OFDM) signal, a plurality of discrete Fourier transform (DFT) values corresponding to the OFDM signal are generated. A plurality of magnitude or power values corresponding to the plurality of DFT values is determined. It is determined whether the plurality of magnitude or power values corresponds to a pattern of magnitude or power values. An indication that the synchronization field is detected in the OFDM signal is generated based on whether it is determined that the plurality of magnitude or power values correspond to the pattern of magnitude or power values.

Method and apparatus for clear channel assessment qualification

A radio frequency transmitting system includes a programmable amplifier, a power amplifier, a power detector, and a calibration module. The programmable amplifier is configured to amplify an input signal to generate an amplified signal. The power amplifier is configured to output a transmit signal in response to the amplified signal. The transmit signal has a transmit power. The power detector is configured to generate a power measurement in response to the transmit power. The calibration module is configured to implement a plurality of feedback loops to adjust a gain of the programmable amplifier in response to a difference between the power measurement and a desired transmit power. The calibration module is configured to select one of the plurality of feedback loops in response to the desired transmit power.

Closed-loop power control in conjunction with adaptive power amplifier linearization

An apparatus has demodulation circuitry to demodulate a radio frequency signal and produce a baseband signal, wherein the radio frequency signal comprises a periodic signal having a predetermined period. An analog-to-digital converter converts the baseband signal into a digital signal that comprises a periodic signal having the predetermined period. A first DC offset adjustment circuit estimates a DC offset contained in the digital signal based on digital samples in a sample period having a length equal to the predetermined period. A second DC offset adjustment circuit estimates the DC offset contained in the digital signal. A selection circuit selects one of the first DC offset adjustment circuit or the second DC offset adjustment circuit to be used to estimate the DC offset contained in the digital signal.

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Santa Clara, CA, United States of America

Sergey Timofeev