Abstract: Exemplary embodiments of system and method are provided for measuring signal amplitude, phase and/or delay offsets between multiple transmit signals fed through the transmit signal processing chains and wirelessly transmitted over the transceive antennas of separate transceiver modules, wherein transmit signal coupling between the transmit antennas of said transceiver modules' transmit signal processing chains may be used for synchronizing the transmit signals and calibrating their amplitude, phase and/or delay parameters. The exemplary embodiments further provide a front end arrangement of a wireless transceiver device which can comprise at least two independently controllable transceiver modules, each connected to an associated spatial diversity transceive antenna and comprising at least one associated transmit signal processing chain and at least one associated receive signal processing chain coupled to a common baseband processing unit.

Abstract: An scheme to provide local oscillator feedthrough offset cancellation to remove baseband and radio frequency coupled offsets. Two separate offset cancellation currents are injected at a driver which drives a baseband signal into a mixer to mix with a local oscillator signal. One offset cancellation current cancels a baseband local oscillator feedthrough offset, while the other offset cancellation current cancels a radio frequency local oscillator feedthrough offset.

Abstract: A method and apparatus are disclosed for analyzing and designing various network configuration scenarios. A modular design allows market assessment and network planning functions to be performed more efficiently and accurately using a single integrated design tool. Wired and wireless access technologies can be modeled and evaluated. In an exemplary implementation for modeling and evaluating fixed wireless access networks, the network planning tool comprises a market scenario planner, a cluster analysis tool, a hub sector planner and a network architecture planner. Generally, the market scenario planner analyzes a listing of potential customers to generate a list of target customers. The cluster analysis tool allows the network planner to identify “clusters” of demand for potential hub placement. The hub sector planner analyzes the hub assignments generated by the cluster analysis tool and allocates each building in a given hub to a particular sector.

Abstract: A Doppler compensation method is used for radio transmission between a mobile body possibly but not exclusively a train and some base station, both mobile body and base station comprise respectively a transceiver connected to an antenna for the radio transmission. The method comprises the step of determining the direction of motion of the mobile body with respect to the active base station i.e. the base station to which a radio transmission link is just built. The method is then followed by the step to apply a constant Doppler compensation corresponding to the cancellation of the Doppler effect for a mobile body moving in the same direction at predefined limiting speed of motion (vlimit) at which a quality threshold is reached with the used radio transmission technology in the case without a Doppler compensation.

Abstract: A method of determining at least an estimate of media latency for push-to-talk communications includes determining a first time associated with transmitting a first packet from a push-to-talk transceiver device. In a disclosed example, the same device receives a second packet that corresponds to the first packet and includes an indication of the first time, a second time associated with receipt of the first packet by another device such as a push-to-talk server and a third time associated with transmission of the second packet to the push-to-talk transceiver device. That same device determines a fourth time associated with receipt of the second packet. In a disclosed example, the push-to-talk transceiver device uses a relationship between the first time, second time, third time and fourth time for determining at least an estimate of media latency associated with the push-to-talk communication corresponding to the first and second packets. A plurality of latency test procedures are disclosed.

Abstract: A method for calibration of RF paths of a frequency hopping adaptive base transceiver station is provided. The method of calibration calibrates a wireless cellular telecommunication system with a frequency hopping adaptive base transceiver station including an adaptive antenna array with two or more RF traffic transceiver apparatus chains. The wireless cellular telecommunication system communicates with mobile units on a frequencies defined by a hop list. The method of calibration includes the step of periodically interrupting a frequency hopping process of the frequency hopping adaptive base transceiver station while calls are in progress. The method of calibration further includes the step of calibrating an antenna transmit path for a RF traffic transceiver apparatus chain at a frequency selected to include one or more frequencies in the hop list to determine a set of weighting parameters for the antenna transmit path at the one or more frequencies.

Abstract: A phase frequency detector comprising a detection circuit and a reset circuit. The phase frequency detector may receive a feedback signal having a predetermined pulse width. The detection circuit may generate a first control signal based on a reference signal, and a second control signal based on the feedback signal. The reset circuit may generate a reset signal used for resetting the detection circuit based on the first control signal, the second control signal, and the feedback signal. The feedback signal may be tied to the generation of the reset signal such that, during a locked state, the pulse width of the second control signal is approximately equal to the pulse width of the feedback signal, which helps reduce the sensitivity of the circuit to nonlinearities.

Abstract: A radio communication unit includes: a reference-signal extraction section that extracts a phase of a reference signal from a baseband signal; a frequency-shift calculation section that calculates a phase shift of the received reference signal with respect to time, and calculates a frequency shift of the received carrier frequency; and an estimation-range decision section that determines, based on the calculated frequency shift, an estimation range used in the frequency-shift calculation section for estimating the frequency shift in a next slot.

Abstract: The invention relates to a method for selecting radio resources for a communication session in a wireless communication terminal. In order to facilitate the selection of quality of service between diversified terminals, terminal capabilities are described by a set of capability parameters, the set including at least one parameter indicative of the terminal's capabilities. Based on the set of capability parameters, a dedicated quality class set is defined for an application instance residing in the terminal, the quality class set including at least one quality class for the application instance. When a session is to be established between at least two application instances residing respectively in at least two terminals, at least one quality class is negotiated for the session, the at least one quality class being determined based on the dedicated quality class sets of the at least two application instances. Based on the negotiation, radio resources are then allocated for the session.

Abstract: A receiver includes an RF bridge and a processor coupled to the RF bridge to receive an information signal from the RF bridge. The processor includes a clock source and a processor front end. The processor front end includes first and second frequency sources, a processor down converter and an analog to digital converter. The first frequency source generates a reference signal based on a signal from the clock source. The reference signal is coupled to the RF bridge. The second frequency source generates a first local oscillator signal based on the signal from the clock source. The processor down converter heterodynes the first local oscillator signal and the information signal. The analog to digital converter is coupled to the processor down converter and provides a digitized down converted signal.

Abstract: Various aspects of a method and system from signal quality measurement based on mean phase error magnitude of a signal are presented. Aspects of the system may comprise circuitry that receives a time phase corrected Bluetooth signal via an RF channel. The circuitry may generate a phase error signal based on the received time phase corrected Bluetooth signal, and generate a mean phase error signal based on the generated phase error signal. A signal to noise ratio (SNR) may be derived based on the generated mean phase error signal, and a data rate may be selected based on the derived SNR.

Abstract: A radio base station apparatus provided with an array antenna having a plurality of antenna elements for calibrating a phase difference among the array antenna elements. The base station has a probe signal adding unit which divides one probe signal and adds the divided probe signals to each receive signals received by the plurality of antenna elements. A probe data extracting unit extracts the probe data from the receive signals added with the probe signal. A phase calibration calculation unit calculates correlating phase calibration values required for calibrating a phase of each receive signal based on the probe data extracted by the probe signal extracting unit. A phase calibration unit calibrates a phase difference among the array antenna elements by calibrating the phase of the each receive signal based on the phase calibration from the phase calibration calculation unit.

Abstract: Non-line-of-sight (NLOS) identification and mitigation are carried out in a wireless positioning system based on channel statistics derived from multipath components of a received signal. The statistics may be based on the kurtosis, the mean excess delay spread, or the root mean square delay spread. The results are justified using IEEE 802.15.4a ultrawideband channel models. Amplitude and delay statistics based on the IEEE models are shown to be log-normal random variables. A joint likelihood ratio test is presented for the LOS and NLOS identification.

Abstract: A method mitigates NLOS conditions based on weighted least squares (WLS) technique, in which the weights are derived from multipath components (MPCs) of the received signals. The weighting methodology can be used with both linear and non-linear least squares models, as well as different other NLOS mitigation schemes, such as residual based algorithms or maximum likelihood techniques.

Abstract: Frequency dependent I/Q imbalance in real I/Q filter pairs compensation may be performed using a simple compensation module, placed in the receiver/transmitter chain, with a gain adjustment coefficient and a delay adjustment coefficient. The gain adjustment coefficient may be determined by amplitude measurements conducted at a selected frequency near the center of the band-pass region of the filters. The delay adjustment coefficient may be determined by phase measurements conducted at a selected frequency near the edge of the band-pass region of the filters. Statistical analysis may be used to determine types of real filters that are better suited for the compensation method and to select the test frequencies that should be used.

Abstract: Apparatus and method for calibration in a multi-antenna system are provided. The method includes setting at least two transmission paths connected to antennas, respectively, as reference transmission paths, when receiving compensation signals transmitted in the reference transmission paths in at least two reception paths connected to the antennas, respectively, determining a phase difference of the reception paths using the received compensation signals, and calibrating the reception paths using the phase difference of the reception paths.

Abstract: A positioning system using a mobile Internet signal is disclosed. The positioning system includes access points for transmitting downlink signals for mobile Internet communications, an access terminal for generating positioning information using the downlink signals received from the access points and access point information on the access points, and a position determination entity (PDE) for calculating range values between the access terminal and the access points using the positioning information from the access terminal and determining a position of the access terminal using the range values. Since the positioning system determines the position using the mobile Internet signal, an accurate terminal position can be determined even in such environments as downtown, shaded and indoor areas.

Abstract: At least one embodiment of the invention provides an automated frequency offset compensation method, system, and apparatus that improves throughput between one or more wireless communication devices by compensating for frequency offsets caused by a Doppler effect. In particular, one implementation estimates the frequency offset and uses this to compensate the carrier signal power to interference power ratio (C/I) when the transmitting and receiving devices are moving relative to each other such that a Doppler effect creates a frequency offset in the perceived frequency of the received carrier signal.

Abstract: A method of producing a reliability metric for a parameter estimate derived from a signal using correlation analysis is described. The method begins by obtaining an indication of whether a non line of sight signal condition is present or likely and/or obtaining an indication of whether a multi-path signal condition is present or likely. Responsive to one or both of these indications, the method derives a reliability metric for the parameter estimate. In one embodiment, the parameter estimate is an estimate of time of arrival (TOA) of the signal, and the reliability metric is root mean square error (RMSE) of the time of arrival estimate. This embodiment obtains an indication of whether a non line of sight signal condition is present or likely based on a measure of the strength of the correlation function at the peak thereof.

Abstract: In a cellular communications system having a centralized radio processing portion (a base station hotel) in communication with a plurality of remote air interface radio portions (or radio heads) over a transport medium, the centralized radio processing portion compensates for a fixed delay associated with the transport medium coupling the centralized radio processing portion and one of the remote air interface radio portions when evaluating a time period corresponding to a variable delay between transmission by a mobile in communication with the one of air interface radio portions and receipt of the transmission by the centralized radio processing portion. The variable delay may relate to time out periods or time slot synchronization.

Abstract: A power generation system including a RF power generator which provides a RF output power. The power distribution system includes a phase-magnitude detector module having a dual logarithmic amplifier phase-magnitude detector. The dual logarithmic amplifier phase-magnitude detector receives current and voltage signals. The dual logarithmic amplifier phase-magnitude detector generates a phase signal that varies in accordance with the phase between the voltage signal and the current signal and a magnitude signal that varies in accordance with the magnitude between the voltage and current signals. A controller receives the phase and magnitude signal and communicates control signals to the matching network.

Abstract: A multiple antenna wireless system including a transmitter and a receiver comprises a reconfigurable large antenna array having a plurality of antennas. A plurality of RF chains in the transmitter is coupled to the reconfigurable large antenna array. A pilot assisted round robin channel estimation means tracks the fading channel; and an adaptive round robin transmit beamforming means beam forms the reconfigurable large antenna array. A method for multiple antenna wireless communication comprising the steps of tracking a plurality of fading channels in a reconfigurable large antenna array having a plurality of antennas using pilot assisted round robin channel estimation to selectively couple a plurality of RF chains in the transmitter to the reconfigurable large antenna array, and adaptively, round-robin transmit beamforming the reconfigurable large antenna array.

Abstract: A method and apparatus of a receiver estimating a plurality of channels is disclosed. The method includes the receiver receiving a composite signal. The composite signal includes a signal from each of a plurality of transmission antennas, wherein the signal of each transmission antenna includes a delay relative to other signals of other antennas. The receiver estimates channels between the receiver and the plurality of transmission antennas based on amplitude and a phase of a received composite signal, at a plurality of frequencies.

Abstract: In a RAKE receiver delays associated with multipath signals are determined by subtracting power values associated with sidelobes of a peak value for each of the multipath signals. The determination can be performed in two stages, in the first stage the determination of the delays is made without accounting for a phase difference between adjacent multipath signals, while in the second stage the determinations are made accounting for the phase difference.

Abstract: Disclosed is a method for estimating the velocity of a mobile station in Rician fading environments in which a direct wave exists. Cellular mobile communication environments include two environments, Rician fading environments in which a direct wave exists and Rayleigh fading environments in which a direct wave does not exist. Generally, many methods for estimating the velocity of a mobile station have been known in Rayleigh fading environments. However, in Rician fading environments in which a direct wave exists, many errors occurs in estimating the velocity of a mobile station due to difficulty in estimation of a Rician coefficient K and an incident angle ?0. According to the invention, a method is provided wherein error is mostly eliminated in estimating the velocity of a mobile station by obtaining a maximum Doppler frequency of the mobile station, even without directly obtaining a Rician coefficient K and an incident angle ?0.

Abstract: A method for identifying occurrence of shadowing phenomenon is to be implemented using a wireless communications system that includes signal transmitting and receiving devices. The signal-receiving device periodically executes a synchronization process to evaluate quality of wireless communications conducted through a signal transmission path between the signal transmitting and receiving devices. A set of signal-state estimated values that includes phase and power parameters is generated during each synchronization process. The method includes: collecting the phase parameters for a number of the synchronization processes; generating a set of Poincaré coordinate data from the collected phase parameters; analyzing distribution of the set of Poincaré coordinate data on a Poincaré map; and determining that the signal transmission path is experiencing a shadowing phenomenon in case of a non-elliptical distribution.

Abstract: A method for determining a measurement time period for measuring a propagation environment in a wireless station set having a plurality of wireless stations, between which wireless communication is made using a channel selected from a plurality of channels different in frequency. The method includes the steps of: obtaining a measurement time period in another wireless station set having a plurality of wireless stations; and determining the measurement time period in the own wireless station set so as to have a time period that does not overlap the obtained measurement time period.

Abstract: A filter frequency characteristic detection device includes a filter which receives a first signal and a second signal, a comparator which compares the first signal and the second signal which have passed through the filter, an offset adjusting circuit which gives an offset to each of the first signal and the second signal to be input to the comparator, a duty ratio detection circuit which detects, as a duty ratio, a change in an amplitude of the first signal and the second signal based on an output result from the comparator, and a frequency characteristic adjusting circuit which adjusts the frequency characteristic of the filter based on a detection result from the duty ratio detection circuit.

Abstract: The present invention provides a radio base station for preventing degradation of transmission quality characteristics even when there are time differences between the instant of channel estimation of uplink time slots UL#1 to UL#N and the instant of transmission of transmission data via downlink time slots DL#1 to DL#N. The radio base station includes transmit diversity controllers 141 to 14N for controlling transmit diversity to be used for downlink time slots DL#1 to DL#N and a data transmitter 15 for transmitting data via downlink time slots DL#1 to DL#N using the controlled transmit diversity.

Abstract: In a phase adjusting method and device in which a phase deviation between main signal frames themselves returned from a station end device through an antenna end device to the station end device without using a control signal for the phase adjustment, a reference signal generated in a first device is commonly mapped to respective down main signal frames of a first and a second system to be outputted to a second device, the second device maps, pointer values indicating timings of the reference signal in the respective down main signal frames to respective up main signal frames of the first and the second system to be outputted to the first device, and the first device extracts respective pointer values from the respective main signal frames and adjust frames of the respective up main signal frames based on the respective pointer values.

Abstract: In a cellular communications system having a centralized radio processing portion (a base station hotel) in communication with a plurality of remote air interface radio portions (or radio heads) over a transport medium, the centralized radio processing portion compensates for a fixed delay associated with the transport medium coupling the centralized radio processing portion and one of the remote air interface radio portions when evaluating a time period corresponding to a variable delay between transmission by a mobile in communication with the one of air interface radio portions and receipt of the transmission by the centralized radio processing portion. The variable delay may relate to time out periods or time slot synchronization.

Abstract: A method and system for determining the time of arrival of a direct radio signal. The system including a receiver (210) for receiving a plurality of signals, wherein each of the plurality of received signals has an associated time of arrival. The system further including a processor (215) adapted to compute a impulse response function of a received signal; decompose an impulse response function comprising the time of arrival for each of the plurality of received signals; and identify a smallest time of arrival from the decomposed impulse response function.

Abstract: A propagation delay-propagation loss table is stored in advance in a radio base station, a first area and a second area being set in advance in the propagation delay-propagation loss table, the first area being predicted to contain the relation between the propagation delay and propagation loss when a mobile station is not within the service area of a repeater, while in the second area the effect of the control delay and power gain caused by the repeater upon this first area is taken into consideration. In the radio base station, it is then determined that a mobile station is within the service area of the radio base station when the relation between the propagation loss value that has been reported from the mobile station and the propagation delay that has been calculated is contained within the first area, and it is determined that the mobile station is within the service area of the repeater when the relation is contained within the second area.

Abstract: This invention is to prevent deterioration in communication quality of closed loop transmission power control, which may occur when the change in transmission power cannot keep up with a sudden change in the state of a transmission path. Transmission power control command extractor 4 extracts a transmission power control command from the uplink signal that has been received by receiver 2. Mobile position predictor 7 predicts the future position of the mobile station from its present position as recognized by mobile position recognizer 5 and from its present rate of movement as recognized by mobile velocity recognizer 6. Database 8 records the state of the downlink transmission path as a function of mobile position. Transmission power controller 9 looks up database 8 on the basis of the predicted future position of the mobile station and controls the downlink transmission power of base station BS on the basis of (i) the result of this lookup, and (ii) the transmission power control command.

Abstract: A time slot boundary of an unknown cell in a telecommunications system is identified by correlating a received signal with a known code over a range of delay values for each of one or more time slots, wherein the known code is used by all cells in the telecommunications system. Only for each of the delay values that are not associated with a known cell, correlation values obtained at each of the one or more time slots are accumulated. The time slot boundary is identified by determining which of the delay values is associated with a highest accumulated correlation value. One or more stored monitored delay sets may be used to determine which delay values are not associated with a known cell. The one or more stored monitored delay sets may be filtered using delay information obtained over a period of time.

Abstract: A method for trilateration may include receiving a signal via each of a plurality of LOS paths and predicting performance of each LOS path. The method may also include filtering out signals received via LOS paths with performance below a predetermined threshold value. The method may further include performing trilateration using unfiltered signals to substantially determine a location of a device.

Abstract: Techniques to estimate the frequency response of a wireless channel in an OFDM system. In one method, an initial estimate of the frequency response of the wireless channel is obtained for a first group of subbands based on a pilot transmission received via the subbands in the first group. An estimate of the impulse response of the wireless channel is then derived based on the initial frequency response estimate. An enhanced estimate of the frequency response of the wireless channel is then derived for a second group of subbands based on the impulse response estimate. The first and second groups may each include all or only a subset of the usable subbands. Subband multiplexing may be used to allow simultaneous pilot transmissions by multiple terminals on their associated groups of subbands.

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method for performing position location on a subscriber unit in a terrestrial wireless telephone system using a set of satellites each transmitting a signal, the terrestrial wireless telephone system having base stations, including the steps of transmitting an aiding message from the base station to the subscriber unit, said aiding message containing information regarding a data boundary for each signal from the set of satellites, applying correlation codes to each signal yielding corresponding correlation data and accumulating said correlation data over an first interval preceding a corresponding data boundary yielding a first accumulation result, and a second interval following said corresponding data boundary yielding a second accumulation result.

Abstract: A circuit for transmitting a signal has a first signal line and a second signal line, wherein the second signal line is arranged adjacent to the first signal line, such that an interaction between signals being transmitted on the signal lines takes place. The circuit further comprises a first driver for driving a first signal on the first signal line, wherein the first signal comprises a delay. A second driver is configured for driving a second signal on the second signal line depending on the delay of the first signal, such that the delay of the first signal is adjusted due to the interaction of the second signal on the first signal. A method and computer program are also disclosed.

Abstract: A method of employing multipath propagation in wireless radio communications uses an omnidirectional transmitting/receiving antenna at one end of a transmission link to send an interrogating signal across an environment subject to multipath disturbances to a phase-conjugating retrodirective antenna, and the retrodirective antenna returns a communication signal along the multiple pathways taken by the interrogating signal to the omnidirectional antenna despite the multipath disturbances. In a simplex communication mode, the retrodirective antenna sends a return signal mixed with a communication signal to the omnidirectional antenna. In a duplex communication mode, both an omnidirectional antenna and a phase-conjugating retrodirective antenna are operated in tandem at each end of the transmission link to provide effective two-way wireless radio transmissions.

Abstract: A method, system and apparatus for reliable multicarrier communication in the presence of timing phase error is disclosed. Phase noise due to a sampling-time phase mismatch between a transmitter device and a receiver device is measured in a signal. A Gaussian noise power level in the signal is determined, and a gain factor associated with the phase noise is calculated. The gain factor is applied to the Gaussian noise power level to calculate an equivalent noise power. In one aspect, the equivalent noise power is used to determine a signal-to-noise ratio. In another aspect, the signal is a multicarrier signal including a plurality of sub-carriers.

Abstract: A generalized framework is disclosed in which a wide variety of propagation models can be cast in a matrix-based format using arbitrary matrix coefficients. Casting propagation models in the matrix-based framework enables efficient computer implementation and calculation, ease of tuning, admissibility, and aggregating multiple propagation models into a single matrix-based model. Matrix-based propagation models based on transmitter-receiver azimuth orientation, transmitter antenna height, terrain elevation, and clutter are also disclosed. The propagation models can be used in conjunction with automated data acquisition from information sources such as topographic maps, clutter maps, etc.

Abstract: The invention relates to a device and a method for simulating a radio channel, wherein a signal transmitted and received by more than one antenna is simulated. The method comprises supplying an input signal of each antenna to a similar delay line, each delay line comprising a delay element connected in series for each propagation path, weighting an output signal of the delay elements corresponding with each propagation path by a term in dependence of a control vector of each transmitting antenna, by a term describing the distortion of a propagation path, and by a term in dependence of a control vector of each receiving antenna, and adding up the components corresponding with each receiving antenna and obtained from the outputs of the weighting means.

Abstract: The present invention is aimed to provide a radio base station that communicates with a plurality of mobile stations by a method, such as the space division multiplex, of simultaneously multiplexing into the same frequency, and exercise a control using an index that is different from the SIR and can be used in a control exercised to properly separate signals sent from mobile stations from the same frequency. The reception response vector predicting unit (524), provided in the radio base station of the present invention, obtains a reception response vector that indicates a propagation path of a signal from a mobile station to the radio base station, for each of the plurality of mobile stations.

Abstract: A system and method is disclosed which allows for the simultaneous capturing of signals at a plurality of diverse locations. In one embodiment, all transmissions received at each location are recorded for a period of time and after that period of time the recorded transmission is discarded. When a determination is made at any one of the locations that the recorded transmission includes a particular signal configuration, the time of receipt of such particular signal configuration is marked and the recorded transmission at that location is maintained so as to preserve the particular signal. When a location detects a particular signal a control signal is then sent to the other locations to cause the other locations to also “freeze” their recorded transmissions so that the desired particular signal can be retrieved from the recorded transmission. At least a portion of the captured signals at all locations are then communicated to a common point for processing.

Abstract: A transmission and reception apparatus and method for use in a wireless communication system, and an apparatus and method for adaptively transmit and receive a signal according to channel state in a wireless communication system. An apparatus for adaptively performing transmission according to a state of a channel transmitted from a transmitter to at least one receiver includes a signal to interference ratio estimator for estimating a signal to interference ratio of the channel using a signal transmitted from the at least one receiver; and an adaptive transmitter for transmitting data to the at least one receiver on a basis of the estimated signal to interference ratio.

Abstract: A method for determining if a signal received at a radio receiver in a communication system is transmitted to the receiver via a direct radio link comprising the steps of: determining a signal characteristic based on one or more signal measurements collected at the receiver; comparing the signal characteristic as determined with at least one predetermined system parameter; and responsive to said comparison determining if said signal is received via a direct link.

Abstract: Multiple antenna wireless communication systems require accurate knowledge of the transfer function between all paths. This invention discloses a system wherein a test signal generator at a transmitter station and a facsimile generator at a receiver station go through an acquisition and tracking process which aligns the two signals, removing errors in the time base of generation, the frequency offset of generation and the time of arrival, so that a logical processor can compute the frequency transfer function of propagation pathways between the multiple input and multiple output antennas. In turn, these channel measurements are used in an adaptive, concurrently sent communication signal.

Abstract: There present description is directed to a method and a system for determining a time delay between a transmission and a reception of an RF signal in a noisy environment. The method comprises: transmitting the RF signal according to a transmit frequency pattern, the transmit frequency pattern comprising at least three pulses separated by a period of time, each one of the at least three pulses respectively being at each one of at least three different frequencies; receiving a received RF signal comprising the at least three pulses at the at least three different frequencies, each one of the at least three different frequencies associated to a receive phase change; comparing the receive phase change of one of the at least three different frequencies with the receive phase change of another one of the at least three different frequencies to obtain a dispersion phase difference; and calculating the time delay using the obtained dispersion phase difference.

Abstract: A test signal generator at a transmitter station and a facsimile generator at a receiver station go through an acquisition and tracking process which aligns the two signals, removing errors in the time base of generation, the frequency offset of generation and the time of arrival, so that a logical processor can compute the frequency transfer function of the entire propagation path for use in an adaptive, concurrently sent communication signal. The frequency transfer function is conveyed back to the transmit end via a control channel permitting an adaptivity function at the transmit end to influence subsequent selection of communication parameters, among which are typically transmitted data rate, selection of modulation, selection of forward error correcting coding, and selection of frequency band for transmission.