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Moorti, CA

Rajendra Moorti, Mountain View, CA US

Patent application numberDescriptionPublished
20110051791Methods and Systems for Calibrating for Gain and Phase Imbalance and Local Oscillator Feed-Through - Methods and systems for calibrating a transmitter with I/Q imbalance and local oscillator feed-through include generating a test tone, frequency up-converting the test tone, monitoring one or more features of the up-converted test tone, and adjusting one or more features of the transmitter in response to the monitoring. The monitoring optionally includes monitoring a beating of the envelope of the up-converted test tone. In an embodiment, a first harmonic of the up-converted test tone is monitored for local oscillator feed-through (LOFT). Alternatively, baseband data inputs to the transmitter are disabled, and LOFT is measured by measuring power at the transmitter output. A second harmonic of the up-converted test tone is monitored for gain and phase imbalances. The adjusting optionally includes adjusting a gain imbalance, adjusting a phase imbalance, and/or adjusting a DC offset. The adjusting optionally includes an iterative refinement process.03-03-2011

Rajendra T. Moorti, Mountain View, CA US

Patent application numberDescriptionPublished
20090028106Device and method for transmitting long training sequence for wireless communications - A device and method transmits a frame of a wireless communication. The frame includes a preamble that includes a short training sequence and a long training sequence. The long training sequence includes non-zero energy on each of a plurality of subcarriers except a DC subcarrier. A frequency domain window is inserted into the long training sequence to stimulate the subcarriers for channel estimation.01-29-2009
20090285185LONG TRAINING SEQUENCE METHOD AND DEVICE FOR WIRELESS COMMUNICATIONS - A method and device for transmitting a frame of a wireless communication begins by generating a preamble of the frame that includes a short training sequence and at least one long training sequence. The at least one long training sequence includes non-zero energy on each of a plurality of subcarriers except a DC subcarrier. The at least one long training sequence corresponds to the number of antennas and applicable wireless communication standards. A matrix is defined to represent the at least one long training sequence. The preamble is compatible with legacy and current standards. A channel is defined with a set of sub carriers to transmit the frame.11-19-2009
20100110876BACKWARD-COMPATIBLE LONG TRAINING SEQUENCES FOR WIRELESS COMMUNICATION NETWORKS - A network device for generating an expanded long training sequence with a minimal peak-to-average ratio. The network device includes a signal generating circuit for generating the expanded long training sequence. The network device also includes an Inverse Fourier Transform for processing the expanded long training sequence from the signal generating circuit and producing an optimal expanded long training sequence with a minimal peak-to-average ratio. The expanded long training sequence and the optimal expanded long training sequence are stored on more than 52 sub-carriers.05-06-2010

Patent applications by Rajendra T. Moorti, Mountain View, CA US

Rajendra Tushar Moorti, Mountain View, CA US

Patent application numberDescriptionPublished
20080310487Single-chip wireless tranceiver - Embodiments of a wireless transceiver are provided. Embodiments can be used in multiple-input-multiple-output (MIMO) wireless transceivers. In an embodiment, radio control signal bundles are provided as direct parallel interconnects between digital signal processing modules and the radio module of the wireless transceiver to enable a precise low-latency control of radio functions. In another embodiment, a separate physical line is provided to control each radio setting of the radio module, thereby enabling simultaneous real-time control of any number of radio settings. In a further embodiment, the various digital and analog components of the wireless transceiver are integrated within a single chip of the same process technology.12-18-2008
20090143030PROGRAMMABLE TRANSMITTER - A programmable transmitter generates a frame in a frame format according to one of a plurality of operating modes using a frame structure table storing a respective frame format for each of the operating modes. The transmitter includes a frame structure engine that receives a mode selection signal indicative of a select operating mode, and accesses the frame structure table to determine the frame format of the select operating mode. The frame structure engine produces a control signal to a frame generator to control the generation of a frame in the frame format of the select operating mode.06-04-2009
20090268846MODIFIED PREAMBLE FOR PROGRAMMABLE TRANSMITTER - A programmable transmitter generates a frame preamble to train a receiver with respect to a communication link format that corresponds to a transmission mode wherein the transmission mode may comprise transmitting the communication link over one or more antennas. Generally, the invention includes generating a preamble with an arrangement that depends upon whether a Greenfield (high data rate) or mixed mode transmission is to occur and that depends upon a number of spatial streams that are to be generated. One format for high data rate transmission includes a short training sequence, a long training sequence and a signal field. The mixed mode transmission further includes a legacy prefix.10-29-2009
20090270060METHOD AND SYSTEM FOR ANTENNA SELECTION DIVERSITY WITH PREDICTION - Certain embodiments of the invention may be found in a method and system for antenna selection diversity with prediction. An antenna diversity system may use information that it has stored on the antenna selection process in previous frames to predict the starting receiving antenna and the starting transmission antenna for the next frame. The prediction may be based on which antennas were selected in previous frames or may be based metrics associated with performance of the antennas. Prediction may be based on a majority polling scheme of previously selected antennas in a determined number of previous frames. Prediction may also be based on a weighted sum of at least one selection metric for all antennas in a determined number of previous frames. Antenna prediction provides a significant performance improvement by reducing the processing and operational overhead in cases where a transmit or a receive antenna dominates.10-29-2009
20100173590METHOD AND SYSTEM FOR ANTENNA SELECTION DIVERSITY WITH BIASING - Methods and systems for choosing at least one signal path are disclosed. Aspects of the method may include determining a signal quality metric for each of a plurality of signal paths, modifying the signal quality metric for each of the plurality of signal paths, and selecting at least one signal path based on at least one modified signal quality metric. At least one of the signal paths may be cycled through and the signal quality metric may be biased and/or increased and/or decreased for each of the plurality of signal paths by a fixed amount and/or by a predetermined amount. The signal quality metric may also be dynamically changed for each of the plurality of signal paths.07-08-2010

Patent applications by Rajendra Tushar Moorti, Mountain View, CA US

R. Tushar Moorti, Mountain View, CA US

Patent application numberDescriptionPublished
20080310351Preamble Formats for MIMO Wireless Communications - A method for generating a preamble of a frame for a multiple input multiple output (MIMO) wireless communication begins by, for each transmit antenna of the MIMO wireless communication, generating a carrier detect field, wherein, from transmit antenna to transmit antenna, the carrier detect field is cyclically shifted. The method continues by, for a first grouping of the transmit antennas of the MIMO wireless communication: generating a first guard interval following the carrier detect field; and generating at least one channel sounding field, wherein, from transmit antenna to transmit antenna in the first grouping, the at least one channel sounding field is cyclically shifted, and wherein the at least one channel sounding field follows the first guard interval. The method continues by, when the MIMO wireless communication includes more than the first grouping of the transmit antennas, for another grouping of the transmit antennas: generating at least one other channel sounding field, wherein, from transmit antenna to transmit antenna in the another grouping, the at least one other channel sounding field is cyclically shifted, and wherein the at least one other channel sounding field follows the at least one channel sounding field; and generating the first guard interval prior to the at least one other channel sounding field.12-18-2008
20090262859Long training sequence for MIMO WLAN systems - A method for configuring a multiple input multiple output (MIMO) wireless communication begins by generating a plurality of preambles for a plurality of transmit antennas. Each of the plurality of preambles includes a carrier detection sequence at a legacy transmit rate, a first channel sounding at the legacy transmit rate, a signal field at the legacy transmit rate, and Z−1 channel soundings at a MIMO transmit rate, where L corresponds to a number of channel soundings. The method continues by simultaneously transmitting the plurality of preambles via the plurality of transmit antennas.10-22-2009
20100142505MULTIPLE PROTOCOL WIRELESS COMMUNICATIONS IN A WLAN - A method for multiple protocol wireless communications begins by determining protocols of wireless communication devices within a proximal region. The method then continues by determining whether the protocols of the wireless communication devices within the proximal region are of a like protocol. The method continues by, when the protocols of the wireless communication devices within the proximal region are not of a like protocol, selecting a protocol of the protocols of the wireless communication devices within the proximal region based on a protocol ordering to produce a selected protocol. The method continues by utilizing the selected protocol by the wireless communication devices within the proximal region to set up a wireless communication within the proximal region.06-10-2010
20100266064MIMO WIRELESS COMMUNICATION GREENFIELD PREAMBLE FORMATS - A method for multiple input multiple output wireless communication begins by determining protocols of wireless communication devices within a proximal region. The method continues by determining whether the protocols of the wireless communication devices within the proximal region are of a like protocol. The method continues by determining the number of transmit antennas. The method continues, when the protocols of the wireless communication devices within the proximal region are of the like protocol, formatting a preamble of a frame of the wireless communication utilizing at least one of cyclic shifting of symbols, cyclic shifting of tones, sparse tone allocation, and sparse symbol allocation based on the number of transmit antennas.10-21-2010
20110044395MIXED MODE PREAMBLE FOR MIMO WIRELESS COMMUNICATIONS - A preamble of a frame for a multiple input multiple output (MIMO) wireless communication for a first transmit antenna of the MIMO communication includes a legacy preamble portion in accordance with a legacy wireless communication protocol. The preamble of the frame for the MIMO wireless communication for the first transmit antenna also includes a current protocol preamble portion in accordance with a protocol of the MIMO wireless communication. The preamble of a frame for at least a second antenna of the MIMO communication includes a cyclically shifted legacy preamble portion for the frame. The preamble of the frame for the MIMO wireless communication for the second transmit antenna also includes a second current protocol preamble portion in accordance with a protocol of the MIMO wireless communication.02-24-2011

Patent applications by R. Tushar Moorti, Mountain View, CA US

Tushar Moorti, Mountain View, CA US

Patent application numberDescriptionPublished
20090207827HIGH DATA THROUGHPUT WIRELESS LOCAL AREA NETWORK RECEIVER - A method for receiving a frame in a high data throughput wireless local area network begins by receiving a preamble of the frame via a channel in accordance with a default receiver filter mask. The processing continues by validating the preamble. The processing continues by, when the preamble is validated, interpreting the preamble to determine a high data throughput channel configuration. The processing continues by reconfiguring the default receiver filter mask in accordance with the high data throughput channel configuration to produce a reconfigured receiver filter mask. The processing continues by receiving a data segment of the frame in accordance with the reconfigured receiver filter mask.08-20-2009

Patent applications by Tushar Moorti, Mountain View, CA US