38 results about "Pilot phase" patented technology

Position determination accuracy of a wireless communication device may be negatively affected by a large unaccounted GPS doppler bias, which in turn may affect GPS doppler estimations and GPS doppler measurements conducted by the wireless communication device. The quality of GPS doppler measurements is very important for position location, because poor quality GPS doppler measurements may prevent the wireless communication device from acquiring satellites in the most sensitive modes with narrow frequency ranges, which results in reduced GPS pseudorange measurement yield. Large unaccounted GPS doppler bias also adversely affects position accuracy because of the adverse effect on the GPS code phase measurements time propagation to common time prior to their use in position location calculation. The same is true in the case of unaccounted CDMA code doppler, through the adverse effect on the AFLT code phase measurements time propagation to common time prior to their use in a position location engine. This effect is the biggest concern in the case of large search windows. Therefore, the present disclosure provides a method of optimizing GPS based position location in the presence of time-varying frequency error, including the steps of continuously measuring and / or calculating resulting GPS doppler bias and CDMA code doppler bias and then minimizing their adverse effects with regard to position location determination by re-centering GPS doppler search windows based on the GPS doppler bias value, as well as using GPS doppler bias and CDMA code doppler bias value to properly propagate GPS pseudorange and AFLT pilot phase measurements, respectively, to common time prior to their use in a position location engine.

An Orthogonal Frequency Division Multiplexing (OFDM) receiver that employs N second-order phase-lock loops sharing a common integrator (where N is the number of pilots in the system). The N second order phase-lock loops track out independent pilot phase rotations to facilitate the constructive averaging of the pilots' phase information. At the same time, by sharing a common integrator, the OFDM receiver takes advantage of noise averaging over multiple pilots to obtain a cleaner frequency offset estimation. The OFDM receiver may also compensate for FFT window drift by calculating a phase difference between a selected pair of pilots and tracking the rate of change of the calculated phase difference over time. The calculated phase difference is used to control the position of an upstream FFT window after a predetermined phase difference threshold is exceeded. The tracked rate of change is used to continuously adjust the phase of downstream equalizer taps.

An OFDM receiver for interlocking FFT window position recovery with sampling clock control, and a method thereof are provided. This method includes the steps of: extracting a pilot signal from fast-Fourier-transformed OFDM received signals, and detecting inter-pilot phase differences; averaging the detected phase differences for a symbol and normalizing the mean phase difference by dividing it into reference values corresponding to phase differences generated when FFT window errors of at least one sample exist; and simultaneously controlling the FFT window position offset using a value obtained by rounding off the normalized value, and the sampling clock offset using the difference between the round-off value and the normalized value.

The invention relates to a self-adaptive damage compensation method and system for a digital-related optical communication system. The self-adaptive damage compensation method includes inserting two pulse modulation pilot frequency signals symmetrically distributed on an input signal frequency fc (fiber channel) at a transmitting terminal; acquiring an input signal power spectrum by the Fourier transform at a receiving terminal, and receiving the pilot frequency signals of a signal power spectrum and subjecting the pilot frequency signals to location and filtering extraction; calculating size of frequency offset of a vibration laser and performing compensation by a pilot frequency; acquiring pilot time domain waveforms by the Fourier transform and calculating a delay delta tau between two pilot light pulses, and calculating size of dispersion by the delta tau and performing the compensation; finally extracting pilot phase noises and subtracting the same from a signal phase so as to eliminate laser phase noises and nonlinear fiber damages. The self-adaptive damage compensation method has the advantages of high accuracy, low complexity, small occupation of bandwidth and fast response speed, so that self-adaptive compensation of various damages can be realized.

A method for enhancing the accuracy of Advanced Forward Link Trilateration (AFLT) position location calculations is disclosed. A position determination entity (PDE) constructs a statistical database of pilot phase measurements reported by mobile stations (MSs) located in a geographic region about a reference base station (BS). When a MS's location is to be calculated, the MS reports a set of PN phase offsets to the PDE. Using only that set of PN phase offsets, the PDE determines a rough estimate of the MS's location using conventional AFLT and also determines the region within which the MS is located. If the PDE determines that the MS did not report one or more earlier arriving PN phase offsets but reported a delayed multipath component, the PDE sends a message to the MS to look for an earlier arriving PN phase offset at a certain time prior to the reported PN phase offset.

A pilot phase tracking loop for an OFDM receiver including a phase rotator receiving an incoming signal, a fast Fourier transform coupled to a phase rotator output, and a pilot phase error metric including a discrete Fourier transform portion coupled to the phase rotator output. The pilot phase error metric determines a phase error estimate associated with a received OFDM symbol, e.g., a data symbol, from the phase rotator output. A loop filter is coupled to the pilot phase error metric output and an oscillator is coupled to the loop filter output. The oscillator output is coupled to the phase rotator to adjust the phase of subsequent OFDM symbols of the incoming signal. Phase noise introduced by a radio portion of the OFDM receiver and OFDM transmitter is reduced by the baseband portion of the OFDM receiver improving OFDM signal tracking under poor SNR conditions.

A multi-carrier (MC) receiver receives a multi-carrier signal containing data symbols as well as pilot symbols. The MC receiver estimates a carrier frequency offset in a downconverted base-band multi-carrier signal in the frequency domain based on deviations of one or more characteristics of the pilot signals from predetermined values, and corrects for the offset in the time domain. In an embodiment, a second order phase locked loop (PLL) estimates the phase of the pilot signals to determine the carrier frequency offset. Changes in pilot phases caused due to the time domain correction are cancelled to allow the PLL to minimize deviations from the lock position.

Providing a pilot aided phase recovery of a carrier of an input digital signal Zk having signal fields of Ls symbol signals, LP pilot symbol signals ZP(k) and (Ls−LP) data symbol signals Zd(k), by for each signal field:calculating an unwrapped pilot phase estimate {circumflex over (θ)}f(P)(l);initiating with {circumflex over (θ)}f(P)(l) a first digital phase locked loop implementing a phase estimate algorithm and calculating a forward phase trajectory {circumflex over (θ)}F(k) from Zd(k), ks varying between 1 and Ls−LP over the data field (l), {circumflex over (θ)}F(P)(l) having Ls−LP forward phase estimates {circumflex over (θ)}F(ks);and initiating with {circumflex over (θ)}(P)f(l+1) a second digital phase locked loop, implementing a phase estimate algorithm and calculating a backward phase trajectory {circumflex over (θ)}B(ks) from Zd(k), ks varying between Ls−LP and 1 over said data field (l), {circumflex over (θ)}B(ks) having Ls−LP backward phase estimates {circumflex over (θ)}B(ks); andfrom said phase trajectories calculating a phase correction (e−j{circumflex over (θ)}(ks)).

A receiver comprises a multiple source phase estimator. The latter comprises a pilot-phase estimator, a data-driven average phase estimator, a selector and a common interpolation controller. The selector selects either the pilot-phase estimator or the data-driven average phase estimator as the source of determined phase estimates at particular times. At other times, the common interpolation controller provides interpolated phase estimates as a function of a linear interpolation based on a respective determined phase estimate.

A method for compensating frequency deviation of sampling clock on OFDM receiver includes using FFT window controller to control FFT window position for picking up pilot phase deviation angle in current OFDM symbol to derive out offset amount crude estimation of current FFT window, using accumulated average of FFT window offset amount to estimate FFT window offset amount of OFDM symbol accurately, using this accurate offset amount to regulate each sub channel phase after current OFDM symbol is balanced and simultaneously using this accurate offset amount to judge whether FFT window of next OFDM symbol is displaced or not.

A method, a system and a receiver device provide timing and frequency correction in a spatial division multiple access (SDMA) system. A timing and frequency correction (TFC) logic / utility obtains a timing error estimate by using pilot symbols on a slot of six tiles. The TFC logic estimates the timing error based on pilot phase differences between unique pairs of tiles when the frequency separation of the tiles is less than a threshold value. When none of the unique pairs of tiles satisfies the threshold value, the TFC logic estimates timing error based on an exhaustive search for each candidate phase error value. The TFC logic performs timing error correction via a timing error estimate based on pilots from the symbols received on each antenna. The TFC logic performs inexplicit frequency error correction according to phase differences based on relative symbol indices.

In a receiver, a decision-directed phase estimator is used in conjunction with an interpolator to provide a phase estimate for use in carrier recovery. For example, a receiver comprises a pilot phase estimator, a Costas loop and an interpolation controller. The pilot phase estimator provides determined phase estimates at the pilot times and the interpolation controller provides interpolated phase estimates at other times as a function of a linear interpolation based on a respective determined phase estimate and at least one decision-directed phase error estimate from the Costas loop.

A system, a method and computer product for synchronizing of a femto cell with a macro cell, the method comprising: placing a forward link receiver into the femto cell; receiving by a micro cellular network the femto cell transmission timing; and synchronizing the femto cell transmission timing with the macro cellular network transmission timing in reliance on the forward link receiver signal. Further, a system, a method and computer product for allocating pilot phases to femto cells, the method comprising: creating at least as many new potential pilot phases for femto cells as there are for macro cells; and allowing a mobile device on a macro cell to search and find a femto cell pilot without explicitly listing femto pilot phases in the neighbor list.

Weighted ridge regression (WRR) processing is applied to three or more distance measurements to determine the location of a terminal. For example, in an integrated satellite-based navigation system / wireless network, the location of a mobile unit can be determined by applying WRR processing to at least three distance measurements, where one or more of the distance measurements are satellite-based distance measurements (e.g., GPS pseudorange measurements) and one or more are wireless network-based distance measurements (e.g., round-trip delay or pilot phase offset measurements). WRR processing provides improved accuracy in the determination of mobile unit position over conventional least mean square techniques.

An analog mobile station system includes a man-machine interaction module, a control module, a test data derivation module, a database management module and a code / de-code module. An analog mobile station location test system includes: an analog mobile station system, a mobile location center, a location entity and a satellite data receiver. The test method includes: finishing the designing of the test request by the man-machine interaction module and transmits it to the control module to set the time trigger of each test task and the control module sets up the connection with the location entity based on the TCP / IP, the test data derivation module finishes the calculation of pilot phase and satellite false distance, the control module finishes the signaling interaction with the location entity on the location flows by the calculated data to transmit the position result computed by the location entity to the man-machine interaction module.

The invention provides a phase tracking method and a phase tracking system. The phase tracking method comprises the steps of: S1, converting a receiving complex signal into amplitude and phase signals; S2, using a difference between a receiving pilot phase and an ideal pilot phase for phase tracking and compensation; S3, achieving carrier phase compensation by estimating the phase difference on respective subcarriers; and S4, converting the phase-compensated data to the receiving complex signal. The method, after the receiving signal is converted into the frequency domain and the balance is completed, converts the signal into the amplitude and phase signals and uses the difference between the receiving pilot phase and the ideal pilot phase for phase tracking and compensation, takes accountof the phase difference between different subcarriers, estimates the phase difference on respective subcarriers and then achieves the phase compensation, and finally restores the data to a complex signal form. The method performs relevant phase compensation on each subcarrier, and finally achieves a purpose of improving receiving performance.

A pilot and burner apparatus is provided for use in firefighting training. The apparatus includes a main fuel conduit and a main fuel valve. The apparatus includes a pilot tube and a pilot fuel conduit configured to deliver fuel from the main fuel conduit to the pilot tube. The apparatus includes main and pilot fuel valves to respectively control a flow of fuel in the main and pilot fuel conduits. In a pilot phase, the valves direct fuel to the pilot tube. An ignition component is configured to ignite fuel in the pilot tube to generate a pilot flame. In a burn phase, the pilot flame generates a controllable flame out of a main burner pipe by igniting fuel exiting the main fuel conduit. The controllable flame can be delivered to a training structure for training purposes.

A frequency offset correction system includes a phase shift estimation unit and correction unit. The phase shift estimation unit estimates a pilot phase shift from pilot signal data for a plurality of bits, and estimates a data phase shift of data from the pilot phase shift for each bit when the frequency offset of a received signal having data of an in-phase component whose bit rate is variable, and pilot signal data of a quadrature component is small. The correction unit sequentially adds data phase shifts and pilot phase shifts estimated by the phase shift estimation unit, and performs frequency offset correction of the received signal using a phase shift obtained by selectively inserting the estimated pilot phase shifts in the added estimated data phase shifts. A frequency offset correction method is also disclosed.

A method for implementing a new logistics program includes executing a plurality of start-up model phases for the new logistics program, the start-up phases including at least a program development phase, a pilot phase, a go-live phase, and a transition phase. During the program development phase, logistics processes are selected, for the pilot, go-live, and transition phases, to be reviewed during each respective phase. Furthermore, a communication plan is selected to execute between a program developer entity and a program client entity during each respective phase. The new logistics program is piloted during the pilot phase, according to the processes and the communication plan selected for the pilot phase, operated in real-time during the go-live phase, according to the processes and the communication plan selected for the go-live phase, and transitioned to self-sufficient operation during the transition phase, according to the processes and communication plan selected for the transition phase.

The invention discloses a multi-path adjustment method for an orthogonal frequency division multiplexing (OFDM) power line carrier communication system. The method comprises the following steps of: respectively performing fast Fourier transform (FFT) calculation on the first 0-L sampling points by taking a synchronously calculated FFT windowing position as a zero point; according to (L+1) FFT calculation results, respectively extracting phase information of a pilot part in each FFT result; calculating a standard difference of a corresponding pilot phase after each displacement; and taking the minimum standard difference after each displacement as a final FFT windowing position. By the method, the problem that the system performance is reduced because of wrong judgment of correlated peak values caused by multi-path information can be effectively solved.

The invention relates to a method for realizing a passive oriented buoy digital de-multiplexer. The input is passive oriented buoy composite signal undergoing A / D sampling and digital discretization, and the output is omnidirectional signal, east-west signal, north-south signal and locking state signal undergoing the digital discretization. The method comprises the following steps of: firstly, digitally filtering the composite signal to separate the omnidirectional signal, the dipole quadrature modulation signal and the pilot frequency signal, wherein the frequency of the pilot frequency signal is tracked and locked by a pilot frequency phase locked loop so as to further track and lock the phase of the pilot phase signal, provide the sinusoidal and cosine signals with the same frequency and phase, and demodulate the dipole signal undergoing quadrature modulation; further performing the lowpass filtering, outputting the omnidirectional signal, the east-west signal and the north-south signal; and locking the information whether the output value given by a judging module is valid. The method has the advantages of reducing the complexity of a buoy receiver, simplifying the hardware design, eliminating the influence of simulated elements, ensuring the balance of two dipole symmetrical channels and improving reliability and oriented precision.

The invention relates to a selecting method of measuring a plurality of sectors pilots based on time difference location model, wherein the measured pilot phases are divided into groups according to the difference of base stations that its sector is attached; group number is also the base station number that this mobile station time measures this time; judging whether it is needed to preferedly selecting from a plurality of sectors measured under the same base station; if needed, carrying out preferedly selecting from a plurality of sectors measured under the same base station; otherwise carrying out the position calculation to the pilot phase of the using sector of the selected base station, and then sending the selected pilot measurement corresponding to the corresponding sector to a position calculation twister. The invention also relates to a moveable location method and system, comprising a MS pilot measuring system, a pilot measuring preferred system, and a location calculation system, wherein the MS pilot measuring system is used in measuring the pilot phase from the mobile station to every sector around; the pilot measuring preferred system is used in selecting a corresponding number of the pilot measurement from the measured pilot phases, based on the pilot measurement request containing designated numbers transmited by the location calculation system; and the location calculation system is used in the selection and location calculation of the positioning algorithmic.

An analog mobile station system includes a man-machine interaction module, a control module, a test data derivation module, a database management module and a code / de-code module. An analog mobile station location test system includes: an analog mobile station system, a mobile location center, a location entity and a satellite data receiver. The test method includes: finishing the designing of the test request by the man-machine interaction module and transmits it to the control module to set the time trigger of each test task and the control module sets up the connection with the location entity based on the TCP / IP, the test data derivation module finishes the calculation of pilot phase and satellite false distance, the control module finishes the signaling interaction with the location entity on the location flows by the calculated data to transmit the position result computed by the location entity to the man-machine interaction module.