Texas Instruments Corporation

Qualcomm Incorporated

Texas Instruments Sunnyvale Incorporated

Manoneet Singh

Sirikiat Lek Ariyavisitakul

Yehuda Azenkot

Jerry Krinock

Anuj Batra

Jaiganesh Balakrishnan

June Chul Roh

Gregory Lerner

Arvind Lonkar

Sanjiv Nanda

Subrahmanyam Dravida

William Louis Abbott

Nir Tal

Shravan K Surineni

Dan Wolberg

Thomas M Paff

Michael E Wilhoyte

Bruce R Kendall

Shravan K Surineri

Shravan K Qualcomm Incorporated Surineri

Sirikiat L Ariyavisitakul

A novel and useful apparatus for and method of packet detection and carrier frequency offset estimation. The packet detection mechanism is robust to channels and sustains reasonable miss-detect (and false alarm) rates at low SNR values. The mechanism uses a modified combined cross correlation and delay and correlate scheme. A delay and correlate scheme is used in order to handle the effects of multipath while swapping integration and multiplication to increase cross-correlation factors resulting in improved sensitivity in low SNR conditions. Correlation is divided into multiple chains to generate a plurality of partial correlations to observe short patterns in the spread sequence resulting in improved performance in long multipath channels.

Apparatus for and method of robust packet detection and frequency offset estimation

A method in accordance with an embodiment of the invention includes producing a first signal match indication based on at least one match indication indicative of a match between at least one signal received in at least one band and a reference signal. The method also includes producing a first signal multipath combined signal based upon the first signal match indication, and detecting a first peak in the first multipath combined signal.

Robust packet detection, symbol timing, channel length estimation and channel response estimation for wireless systems

Apparatuses and methodologies are described that coordinate multiple wireless communication protocols within a mobile device. A single mobile device can contain multiple communication components (e.g., a Bluetooth component, an IEEE 802.11b/g component). To prevent interference and possible loss of data, one communication component may be prevented from transmitting or receiving data packets while the other communication component is either transmitting or receiving. The components may be coordinated by a central controller located in the mobile device. Alternatively, the communication components may exchange messages to determine transmission or reception priority. In addition, one communication component may monitor the status of the other communication component to determine unused communication slots.

Methods and apparatuses for interworking

Systems and methods for digital communication using an inexpensive reference crystal are described herein. Some illustrative embodiments include a method that includes setting a center frequency of a local oscillator used by a radio frequency (RF) transceiver, sequentially applying each of a plurality of predetermined offsets to the center frequency of the local oscillator, determining a plurality of metrics indicative of the quality of a received signal (each of the plurality of metrics corresponding to a different predetermined offset of the plurality of predetermined offsets), and selecting a predetermined offset of the plurality of predetermined offsets that results in a metric indicating a received signal that is higher in quality than the received signal that results when applying each of the remaining predetermined offsets of the plurality of offsets.

Digital communication using an inexpensive reference crystal

A method. The method includes producing a first signal match indication based on at least one match indication indicative of a match between at least one signal received in at least one band and a reference signal. The method also includes producing a first signal multipath combined signal based upon the first signal match indication, and detecting a first peak in the first multipath combined signal.

A system and method of flexible channel allocation in an ultra wideband frequency hopping communication system is disclosed. In one embodiment, a method includes communicating radio signals through rapidly switching among a band groupaccording to a hopping pattern. The method also includes scanning the ultra wideband spectra to determine the band groupbased on the hopping pattern of the radio signals. In another embodiment, a method includes scanning ultra wideband spectra to eliminate any frequency band of the ultra wideband spectra from a list of available frequency bands when the any frequency band is currently used, selecting a band group in combination of two or more frequency bands to communicate radio signals with an optimal transmission power and/or maximum range, and communicating the radio signals through rapidly switching among the band group.

System and method of flexible channel allocation in an ultra wideband (UWB) frequency hopping communication system

In at least some embodiments, a communication system includes a receiver having a local oscillator (LO) for each of a plurality of frequency bands. Each LO is controlled by a separate phase-locked loop (PLL) that tracks carrier frequency offset (CFO) using a common phase error (CPE). The CPE is selectively weighted based on at least one inter-band frequency correlation (IFC) coefficient.

Systems and methods for tracking communication parameters over a plurality of frequency bands

Prefilters for a receiver with multiple input branches are trained in the frequency domain. The frequency response B of a conditioned channel is determined without reference to the prefilters, and the frequency response W of the prefilters is computed from the frequency response B of the conditioned channel. The prefilters suppress interference.

Frequency domain training of prefilters with interference suppression

Method and apparatus for OFDM synchronization and channel estimation. In a temporal embodiment, received embedded system pilot symbols are inverse Fourier transformed at expected index locations and correlated with computed complex conjugates of inverse Fourier transforms of pilot symbols for providing a correlation function for the channel impulse response. In a frequency domain embodiment, embedded system pilot symbols are augmented with pilot-spaced inferred guard band symbols, multiplied by scaled complex conjugates of computed pilot systems, and inverse Fourier transformed into the channel impulse response. Time and frequency are synchronized in feedback loops from information in the channel impulse response. The channel impulse response is filtered, interpolated, and then Fourier transformed for determining channel estimates for equalization.

Method and apparatus for multicarrier channel estimation and synchronization using pilot sequences

A prefilter is trained as follows. The frequency response B of a conditioned channel is determined without reference to the prefilter, and the frequency response W of the prefilter is computed from the frequency response B of the conditioned channel.

Frequency domain training of prefilters for receivers

A multiple access system for a network using multicarrier modulation. To contend for service a subscriber station selects an upcoming frame in whose contention window it will contend, selects a contention slot within the window, selects a contention channel corresponding to a subset of the carriers used by the network, and imposes a contention code differentially on the carriers in the contention channel.

Method and apparatus for multiuser access in a multicarrier modulation network

A spatial diversity receiver and method for determining a multichannel combined symbol timing marker that identifies an energy concentration for a combination of channel delay spreads in order to reduce the complexity of equalization. The receiver includes two or more receiver chains having spatially diverse antennas; a multichannel combined timer; and a multichannel combined equalizer for receiving wireless signals through two or more signal channels. The multichannel combined timer combines energies corresponding to the channel impulse response coefficients for all the channels for determining a series of multichannel combined metrics having associated index cursors, and then determines the multichannel combined symbol timing marker from the index cursor for the largest of the metrics. The symbol timing marker synchronizes the received symbols issued to the equalizer jointly to the energy concentration for the delay spreads combined for all the channels.

Joint timing recovery for multiple signal channels

A wireless receiver for receiving an incoming signal having spatial and temporal diversity. The receiver uses noise-based prescaling of multiple receiver chain signals for optimally combining the receiver chain signals in a composite equalized signal and uses noise-based time-varying postscaling the equalized signal. The receiver determines noise-based scale factors by comparing signal symbols to dispersed replica symbols of a training sequence for the incoming signal.

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Sunnyvale, CA, United States of America

Manoneet Singh