Patent application number | Description | Published |
20110129234 | Iterative Carrier Phase Compensation in Coherent Fiber Optic Receivers - A method and an optical receiver compensates for an error in a phase of an optical signal in a receiver. The signal includes blocks of symbols in a sequence. Each block is decoded based on a partially phase compensated symbols, and an average phase error for the block is estimated. Forward phase compensation and backward phase compensation is performed on the block based on the average phase error, and the decoding, estimating, performing is iterated until a termination condition is satisfied to produce a phase compensated block. | 06-02-2011 |
20110194452 | Transmitting Data with Multiple Priorities as OFDM Symbols - A transmitter transmits data having a set of two or more priorities on subcarriers using orthogonal frequency division multiplexing (OFDM) symbols. The transmitter includes a media access (MAC) layer, wherein the MAC layer further includes a queue for storing data at each priority, a rate control block connected to each queue, and a physical (PHY) layer. The PHY layer further includes a channel coder for each priority, wherein each channel coder is connected to the corresponding queue to receive data, and to the rate control block to send coding information. | 08-11-2011 |
20120129458 | Wireless Communication Network for Transportation Safety Systems - In a network for a safety system in a transportation system, the transportation system includes a shaft and a car arranged in the shaft. A first wall node is at a first end of the shaft and a second wall node is at a second end of the shaft to communicate safety messages with the car. Each wall node includes at least one wireless transceiver connected to one or more antennas. Each car in the shaft includes at least two wireless transceiver connected to one or more antennas, wherein the first transceiver of the car uses a first frequency and the second transceiver of the car uses a second frequency to communicate each safety messages in duplicate. A wired backbone connects the set of wall nodes to a controller of the safety system of the transportation system. | 05-24-2012 |
20120140922 | Method for Generating Private Keys in Wireless Networks - The first and second nodes in a wireless network estimate first and second channel response. The first node quantizes the first channel response to produce a first bit sequence, and a feed-forward message, which is transmit as a feed-forward message to the second node. The second node quantizes the second channel response using the feed-forward message to produce and an estimate of the first bit sequence, a second bit sequence and a feed-back message, which is transmitted to the first node. Then, the first and second nodes delete bits in the respective bit sequences using the feed-back and feed-forward message to generate first and second private keys with low bit mismatch rate. | 06-07-2012 |
20120147864 | Synchronous Data Transmission in Hybrid Communication Networks for Transportation Safety Systems - A hybrid communication network for a transportation safety system includes a wired network including a set of fixed nodes. Each fixed node includes a wired interface for connecting the fixed node to the wired network and at least one wireless interface. The set of fixed nodes further includes a head node at a first end of the wired network connected to a controller, a terminal node at a second end of the wired network, and a set of relay nodes arranged between the head node and the terminal node. A wireless network includes a set of mobile nodes and a set of fixed nodes connected to the wired network. Each mobile node includes at least one of the wireless interfaces, and each mobile node is arranged in a moveable car. | 06-14-2012 |
20120147879 | Method for Scheduling Data Transmission in Hybrid Communication Networks for Transportation Safety Systems - A hybrid communication network for a transportation safety system includes a fixed wired nodes and mobile wireless nodes. Because the wired nodes operate independently packets transmitted by the wired nodes to the wireless nodes need to be synchronized. A downlink travel time for downlink packets traveling from a controller to the wireless nodes is determined. Then, the controller schedules downlink data intervals (DDI) based on the downlink travel time; and transmits downlink packets to the wireless nodes during the DDI, such that a latency requirement of the transportation safety system is satisfied. | 06-14-2012 |
20120148046 | Secure Wireless Communication Using Rate-Adaptive Codes - Data are communicated in a wireless network between a transmitter to a receiver. The transmitter estimates a first channel response between the receiver and the transmitter at the transmitter, and generating a first key based on the first channel response. The data are encoded at the transmitter using a rate-adaptive code to produce encoded data, which is scrambling using the first key before broadcasting. Subsequently, the receiver can estimate a second channel response to generate a second key to be used to descramble the broadcast data. | 06-14-2012 |
20120170684 | Method and System for Decoding OFDM Signals Subject to Narrowband Interference - A method estimates a wireless channel at a receiver. The signal is transmitted using narrowband orthogonal frequency division demultiplexing (OFDM) and frequency subcarriers, and the signal includes a set of data tones and a set of pilot tones. The channel and pilot tone interference are estimated based on all the pilot tones extracted from the signal and a channel model. The set of data are equalized based on the channel estimate. Data interference is detected according to the pilot interference and the equalized data tones. Subcarrier interference-to-noise ratios are determined based on the data interference. Signal strengths of the data tones are determined based on the equalized data tones, log-likelihood ratios of bits represented by the data tones are determined based on the subcarrier interference-to-noise ratios and the signal strength of the data tones. | 07-05-2012 |
20120207027 | Method for Minimizing Undetectable Errors in Data Packets in Communication Systems - Undetectable errors in packets are minimized by verifying the CRC in each packet, setting a CRC flag to 0 to indicate success, and setting the CRC flag to 1 to indicate failure. If at least one packet in the set of packets fails then generate an error pattern E for each packet by comparing the packet that fails with one packet that passed the CRC verification, and comparing the error pattern to a set of known error patterns. Then, setting a CRC flag to 0 to indicate success and passing the payload of each packet and the CRC flag to the application if the difference is less than a predetermined threshold, and otherwise, setting the CRC flag to 1 to indicate failure. | 08-16-2012 |
20120217817 | Tuning Electromagnetic Fields Characteristics for Wireless Energy Transfer Using Arrays of Resonant Objects - A system for exchanging energy wirelessly includes an array of objects, wherein each object is electromagnetic (EM) and non-radiative and generates an EM near-field in response to receiving the energy. Each object in the array is electrically isolated from the other objects and arranged at a distance from all other objects. An energy driver provides the energy to the array of objects. A receiver, at a relative position with respect to the array receives the energy via resonant coupling of evanescent waves. The system can tunes characteristics of the EM near-field depending on a relative position of the receiver with respect to the array. The tuning can affect frequency, phase and amplitude of the energy field. | 08-30-2012 |
20120217818 | System and Method for Automatically Optimizing Wireless Power - A system transfers energy wirelessly from a source to a sink as an EM near-field according to parameters. The source includes a receive RF chain, and a receive controller. The sink includes a transmit RF chain, and a receive controller. The receive controller measures the energy received as feedback information, which is transmitted to the sink. Then, the transmit controller dynamically varies the parameters to optimized the energy received at the sink. | 08-30-2012 |
20130141156 | High Electron Mobility Transistors with Multiple Channels - A device includes a source for transmitting an electronic charge through a conduction path; a drain for receiving the electronic charge; a stack for providing at least part of the conduction path; and a gate operatively connected to the stack for controlling a conduction of the electronic charge. The stack includes an insulator layer, an N-polar layer and a barrier layer selected such that, during an operation of the device, the conduction path formed in the N-polar layer includes a two-dimensional electron gas (2DEG) channel and an inversion carrier channel. | 06-06-2013 |
20130170842 | Method and System for Equalization and Decoding Received Signals Based on High-Order Statistics in Optical Communication Networks - A method equalizes and decodes a received signal including a sequence of symbols. Subsequences of the signal are selected, wherein the subsequences are overlapping and time shifted. For each subsequence, statistics of the channel corresponding to a pattern in the subsequence are selected, wherein the statistics include high-order statistics. A transmitted signal corresponding to the received signal is then estimated based on the statistics. | 07-04-2013 |
20130178168 | Multi-Band Matching Network for RF Power Amplifiers - A multi-band matching network for RF power amplifiers utilizes multiple impedance transformer branches connected in parallel. Each transformer branch achieves matching at one frequency band. A core of each transformer branch is connected between frequency blocking networks, which reject out-of-band signals. | 07-11-2013 |
20130315077 | Reputation-Based Routing and Error-Correction Coding in Ad Hoc Networks - Nodes in an ad hoc mobile network are monitored to provide secure routing of packets. Malicious or selfish behaviors by nodes are used to maintain and distribute node reputations. Based on the reputation, the most secure route, which can have multiple paths, is selected for packet communications. In conjunction with secure routing, a forward error correction code is adaptively optimized according to the reputation through every adjacent nodes along the route to avoid eavesdropping and falsification by malicious nodes. | 11-28-2013 |
20140133848 | Adaptively Coding and Modulating Signals Transmitted Via Nonlinear Channels - An adaptive coding scheme for nonlinear channels improves reliability and an efficiency in digital communication networks. The method monitors channel statistics to analyze an extrinsic information transfer chart of the channels. The channel statistics are fed back to the transmitter to adapt forward error correction coding. A parametric analysis method uses a Gaussian mixture model. The statistical information feedback can adapt an ARQ sheme by adding a weighted received signal to the original coded signals to reduce nonlinear distortion. Trellis shaping, can make the transmitting signal preferable for nonlinear channels. | 05-15-2014 |
20140241471 | Method and System for Communicating Data Wirelessly Using Probabilistic Data Association - A signal received via a fading channel is decoded in radio frequency receiver by first demodulating the signal to a baseband signal, and serial to parallel converting the baseband signal to a precoded signal. Then, a channel matrix is estimated from the precoded signal, and symbols are detected in the precoded signal using the channel matrix. The decoding uses probabilistic data association. The detecting initializes a probability distribution for each symbol, and selects an ordering in which to update the probability distributions. The probability distribution for each symbol are updated according to the ordering, until a termination condition is reached, and then demapped and parallel to serial converted to estimate a sequence of bits used to generate the signal. | 08-28-2014 |
20140285264 | Reconfigurable Output Matching Network for Multiple Power Mode Power Amplifiers - An impedance matching network for a radio frequency (RF) amplifier includes multiple stages connected to each other in a first to last order. A first stage produces an RE output signal, and a last stage receives an RF input signal. Each stage includes a first inductor connected to produce an output signal, a second inductor connected to receive an input signal from a next stage, a capacitor connected between the first and second inductors and a ground. In addition, each stage other than the first stage further includes a first switch to by-pass the first and second inductors, a second switch connected between the first and second inductors and the ground, and a controller for controlling, the first and second switches to select a particular power level of a set of power levels. | 09-25-2014 |
20150049731 | Method for Coding OFDMA Data without Pilot Symbols - A wireless network includes a set of nodes. Each node includes a transmitter and a receiver. A block of data bits is converted to a block of data symbols. The block of data symbols is partitioning timewise into groups of data symbols. A set of subcarriers is assigned to each group of data symbols, and each group of data symbols is spread to a chip sequence using a coding block of spreading sequences, wherein the spreading sequences are based on types of the groups of data symbols. Then, after the spreading, the chips are transmitted as orthogonal frequency-division multiplexing (OFDM) data symbols on the assigned subcarriers. | 02-19-2015 |