Symbol Technologies, LLC

Linquest Corporation

Kbr Wyle Services, LLC

Simple Technology, Inc.

Hoai Xuan Vu

Toan X Vu

David P Goren

Guang Zeng

Can Xuan Vu

Dao Ngoc Vu

A method for managing data transmissions includes: receiving data transmission requests; and determining which requests to accept such that a constraint of a network communication pathway is not exceeded, by: selecting a set of requests based on value densities, determining a first non-selected request that doesn't exceed a residual amount, determining whether a second non-selected request exists for which: (1) its value density is greater than a combined value density of the first non-selected request and a request of the selected requests that has a lowest value density, and (2) its demand is the largest among non-selected requests meeting requirement (1) that is no larger than a sum of the residual amount and a demand of a lowest value density selected request, and if it exists, replacing the lowest value density selected request with the second non-selected request and, if not, include the first non-selected request as a selected request.

Systems and methods for optimizing data transmission in a capacity constrained data communication network

An amount of propellant remaining in an orbiting satellite can be estimated in a more accurate manner than is possible with conventional approached. Pressure and temperature telemetry data received from the satellite can be analyzed using a maximum likelihood estimation approach that reconstructs a predicted tank pressure signal using the temperature data and determines a pressurant volume necessary to make the reconstructed pressure signal match the received pressure signal. Drift of the pressure data received from pressure transducers in the satellite can also be addressed using the current subject matter, as can issues including but not limited to inaccessible propellant due to satellite spin, tank expansion under pressure, and the like. Independent determinations of the amounts of propellant remaining can be made using moment of inertia calculations in situations in which an axis of spin of the satellite is known a priori.

Estimation of propellant remaining in a satellite

Location of mobile units in a wireless local area network is based on use of signal strength ratios and other criteria. In one embodiment absolute value of signal strength is used to derive a second value of location. The second value may be used as the location if the system is not calibrated and may also be used to calibrate the system. Alternatively time difference of arrival may be used in combination with signal strength ratio.

Method for locating mobile units based on received signal strength ratio

A method for estimating a location of a wireless device in a wireless local network is provided. The method includes forming a first set comprised of the signal strength received from access points that the wireless device received a signal from and an indicator of no signal strength measured for access points that the wireless device did not receive a signal from. Next, a scan subset can be formed comprised of access points in the first set that has associated signal strength. Next, a cluster comprised of the calibration points can be formed based on the scan subset. A distance between the first set and each of the calibration point in the cluster can be calculated. Then, the smallest distance can be selected as the location estimate.

Method and system for radio map filtering via adaptive clustering

A differential ring oscillator is provided with three differential amplifiers and provides three-phase output signals which can be used for synchronous detection of a received multi-phase modulated signal in a multi-phase receiver, wherein the phase of the local oscillator signals may be in other-than-quadrature relation. Two of the phase outputs of the local oscillator can be combined to provide a signal that is in quadrature with the remaining output. The oscillator is preferably controlled in coarse frequency control steps and using a fine voltage control signal responsive to a phase-locked loop to reduce frequency modulation of the oscillator signal arising out of leakage signals.

Multiphase receiver and oscillator

A transceiver having a transmitter section and a receiver section. The transmitter section includes a modulator to superimpose information, i.e., data, onto the amplitude of a suitable carrier signal, such as a microwave frequency carrier signal. The receiver section receives data carried by the carrier frequency signal and, in a heterodyning system, downconverts the received signal to a suitable intermediate frequency signal. The modulator and the downconverter are formed on a single semiconductor body, or chip of silicon. The receiver section is adapted to receive signals over a predetermined overall bandwith having frequencies within a plurality of frequency channels, each one of the channels having a predetermined channel bandwidth; and, a sampler for sampling such received signals at a sampling frequency less twice the predetermined bandwidth. The sampling frequency is selected to convert the carrier frequency of a signal within a selected one of the frequency channels to a frequency within a predetermined intermediate frequency and to convert the carrier frequencies of signals of the un-selected one of the frequency channels to frequencies above other than the predetermined intermediate frequency. The downconverted signals are converted into corresponding digital signals. A demodulator includes a Hilbert-Transform-pair filter section. The receiver includes: a first automatic gain control circuit (AGC) and is responsive to an output of the digital signal processor, for adjusting the gain of the AGC circuit in accordance with the output of the digital signal processor; and, a second AGC circuit fed by the digital signals and the output of the digital signal processor, for adjusting the gain of the magnitude of the digital signals in accordance with the output of the digital signal processor.

Radio frequency transceiver and subassemblies thereof

The present invention is a method and apparatus for signal conditioning which reduces non-linear distortion caused by RF/FM transmitters by lowering the carrier frequency of the modem transmit signal. This is accomplished by lowering the highest frequency in the input signal to the RF/FM transmitter. In one embodiment, modem datapumps are modified so that the optimal modem carrier frequency is utilized for data modulation. The optimal carrier frequency is computed by placing the lowest frequency component in the transmit spectrum at the low band-edge of the RF channel. In other embodiments, a conventional modem transmit spectrum is shifted to the optimal carrier frequency, which is determined by the method described above. Another aspect of the present invention involves the modification of the receiving modem to operate with both conventional land-line modems and the present invention modified-carrier modems used in conjunction with the cellular telephone network. This is accomplished by implementing energy-correlation filters which determine the frequency band over which the received signal energy is distributed.

Method and apparatus for improving data transmission over a wireless

The receiver for receiving data carried by the carrier frequency signal and, in a heterodyning system, for downconverting the received signal to a suitable intermediate frequency signal. The modulator and the downconverter are formed on a single semiconductor body, or chip of silicon. The receiver section is adapted to receive, over a predetermined overall bandwidth, signals having carrier frequencies within a plurality of frequency channels, each one of the channels having a predetermined channel bandwidth. The downconverted signals are converted into corresponding digital signals. A demodulator includes a pair of filters having Hilbert-Transform relationship with respect to each other. The receiver includes: a first automatic gain control circuit (AGC) which is responsive to an output of the digital signal processor, for adjusting the gain of the AGC circuit in accordance with the output of the digital signal processor; and, a second AGC circuit fed by the digital signals and the output of the digital signal processor, for adjusting the gain of the magnitude of the digital signals in accordance with the output of the digital signal processor.

Radio frequency receiver with automatic gain control

An oscillator is provided having a plurality of cascade coupled inverters Each one of the inverters is a differential amplifier having a p-input and an n-input. The output of each one of the amplifiers is connected to: the n-input of the next succeeding amplifier to provide a closed loop, or ring oscillator; and, the p-input of an amplifier positioned an even number of amplifier stages forward of such next succeeding amplifier. In a preferred embodiment, each amplifier in the ring includes an n channel transistor (nMOS transistor) connected in a totem pole arrangement, to a p channel transistor (pMOS transistor). The gate of the nMOS transistor provides the n-input and gate of the pMOS transistor provides the p-input. The source and drain paths of the pMOS and nMOS transistors are connected together to provide an output for the amplifier. With such arrangement, because the gate of the more slowly responding pMOS transistor is driven before the gate of the nMOS transistor the oscillator is adapted to operate at a higher frequency of oscillation.

Growing community of inventors

Westminster, CA, United States of America

Hoai Xuan Vu