Acorn Technologies, Inc.
|Acorn Technologies, Inc. Patent applications|
|Patent application number||Title||Published|
|20150333933||Least Squares Channel Identification for OFDM Systems - An OFDM system generates a channel estimate in the time domain for use in either a frequency domain equalizer or in a time domain equalizer. Preferably channel estimation is accomplished in the time domain using a locally generated reference signal. The channel estimator generates an initial estimate from a cross correlation between the time domain reference signal and an input signal input to the receiver and generates at least one successive channel estimate. Preferably the successive channel estimate is determined by vector addition (or subtraction) to the initial channel estimate. The at least one successive channel estimate reduces the minimum mean square error of the estimate with respect to a received signal.||11-19-2015|
|20150043629||BLOCK TIME DOMAIN CHANNEL ESTIMATION IN OFDM SYSTEM - An OFDM receiver receives OFDM symbols in the frequency domain and comb filters and then punctures the OFDM symbols to leave symbols with actual pilot information and with null values at the data symbols. The receiver provides the punctured OFDM symbols to an OFDM symbol queue. A virtual pilot interpolator is coupled to the punctured OFDM symbol storage to generate virtual pilot information introduced to OFDM symbols. The interpolator may be a two dimensional Wiener filter. The receiver also includes a time domain channel estimator that processes a first OFDM symbol including virtual pilot information to generate a channel impulse response for the first OFDM symbol. A frequency equalizer equalizes the OFDM symbol in response to the channel impulse response for the first OFDM symbol.||02-12-2015|
|20140369372||Tensile Strained Semiconductor Photon Emission and Detection Devices and Integrated Photonics System - Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.||12-18-2014|
|20140334530||OFDM RECEIVER WITH TIME DOMAIN CHANNEL ESTIMATION - An OFDM communication system performs time domain channel estimation responsive to received symbols before the symbols are processed by a fast Fourier transform. The communication system generates virtual pilots from actual pilots to improve the stability and quality of channel estimation. The system generates a reference signal from the actual and virtual pilots and correlates the resulting reference signal with a signal responsive to the received symbol to generate an initial channel impulse response (CIR) and to determine statistics about the channel. In some circumstances, the resulting reference signal is correlated with a modified symbol in which the actual and virtual pilot locations are emphasized and the data locations are deemphasized. Time domain channel estimation iteratively improves on the initial CIR. The system determines channel estimates for data only symbols through averaging such as interpolation.||11-13-2014|
|20140199813||TRANSISTOR WITH LONGITUDINAL STRAIN IN CHANNEL INDUCED BY BURIED STRESSOR RELAXED BY IMPLANTATION - Processes for making field effect transistors relax a buried stressor layer to induce strain in a silicon surface layer above the buried stressor layer. The buried stressor layer is relaxed and the surface layer is strained by implantation into at least the buried stressor layer, preferably on both sides of a portion of the surface layer that is to be stressed. For example, implanting ions through the surface silicon layer on either side of the gate structure of the preferred FET implementation into an underlying stressor layer can induce strain in a channel region of the FET. This process can begin with a silicon or silicon-on-insulator substrate with a buried silicon germanium layer having an appropriate thickness and germanium concentration. Other stressor materials can be used.||07-17-2014|
|20140170826||BIAXIAL STRAINED FIELD EFFECT TRANSISTOR DEVICES - A process for forming contacts to a field effect transistor provides edge relaxation of a buried stressor layer, inducing strain in an initially relaxed surface semiconductor layer above the buried stressor layer. A process can start with a silicon or silicon-on-insulator substrate with a buried silicon germanium layer having an appropriate thickness and germanium concentration. Other stressor materials can be used. Trenches are etched through a pre-metal dielectric to the contacts of the FET. Etching extends further into the substrate, through the surface silicon layer, through the silicon germanium layer and into the substrate below the silicon germanium layer. The further etch is performed to a depth to allow for sufficient edge relaxation to induce a desired level of longitudinal strain to the surface layer of the FET. Subsequent processing forms contacts extending through the pre-metal dielectric and at least partially into the trenches within the substrate.||06-19-2014|
|20130202055||METHOD AND SYSTEM FOR ACTIVATION OF PERFORMANCE ENHANCEMENTS FOR MOBILE DEVICES - A software upgrade application can be downloaded to a handset to selectively enable enhanced functionality physical layer circuitry. In a particular implementation, an OFDM handset or other portable modem includes selectively enabled time domain channel estimation circuitry. An upgrade application within the handset is activated. The handset is checked to confirm compatibility with the enhanced functionality and the upgrade application is checked to confirm its authenticity. The upgrade application then activates the enhanced functionality within the physical layer of the device.||08-08-2013|
|20130140629||INSULATED GATE FIELD EFFECT TRANSISTOR HAVING PASSIVATED SCHOTTKY BARRIERS TO THE CHANNEL - A transistor having at least one passivated Schottky barrier to a channel includes an insulated gate structure on a p-type substrate in which the channel is located beneath the insulated gate structure. The channel and the insulated gate structure define a first and second undercut void regions that extend underneath the insulated gate structure toward the channel from a first and a second side of the insulated gate structure, respectively. A passivation layer is included on at least one exposed sidewall surface of the channel, and metal source and drain terminals are located on respective first and second sides of the channel, including on the passivation layer and within the undercut void regions beneath the insulated gate structure. At least one of the metal source and drain terminals comprises a metal that has a work function near a valence band of the p-type substrate.||06-06-2013|
|20130119446||METHOD FOR DEPINNING THE FERMI LEVEL OF A SEMICONDUCTOR AT AN ELECTRICAL JUNCTION AND DEVICES INCORPORATING SUCH JUNCTIONS - An electrical device in which an interface layer comprising arsenic is disposed between and in contact with a conductor and a semiconductor. In some cases, the interface layer may be a monolayer of arsenic.||05-16-2013|
|20130039664||TENSILE STRAINED SEMICONDUCTOR PHOTON EMISSION AND DETECTION DEVICES AND INTEGRATED PHOTONICS SYSTEM - Tensile strained germanium is provided that can be sufficiently strained to provide a nearly direct band gap material or a direct band gap material. Compressively stressed or tensile stressed stressor materials in contact with germanium regions induce uniaxial or biaxial tensile strain in the germanium regions. Stressor materials may include silicon nitride or silicon germanium. The resulting strained germanium structure can be used to emit or detect photons including, for example, generating photons within a resonant cavity to provide a laser.||02-14-2013|
Patent applications by Acorn Technologies, Inc.