4692results about "Line-transmission monitoring/testing" patented technology

An apparatus and process for allocating carriers in a multi-carrier system is described. In one embodiment, the process comprises determining a location of a subscriber with respect to a base station, selecting carriers from a band of carriers to allocate to the subscriber according to the location of the subscriber with respect to the base station, and allocating selected carriers to the subscriber.

A transmitter comprises a local oscillator circuit operable to generate a reference signal, a modulator circuit operable to generate a data-carrying signal using the reference signal, and a test signal generator circuit operable to generate a test signal using the reference signal. The test signal has a first bandwidth, and a test signal insertion circuit is operable to combine the data-carrying signal and the test signal to generate a combined signal. An amount of bandwidth in the combined signal allocated to the test signal is greater than the first bandwidth such that a component of the combined signal corresponding to the test signal is bordered by whitespace. A receiver may then use the test signal to determine and correct for phase noise introduced in the transmitter.

A method and apparatus for maintaining network connectivity over power lines is disclosed. Such network connectivity is maintained even if various customers are covered by different power line networks or if one or more power lines in a network are unavailable to transmit data. More particularly, in order to bridge a gap in a power line network, one or more messages are extracted from a first node in a power line network and are then transmitted to a second node via free space transmission, illustratively wireless radio frequency (RF) transmission conforming to one or more of the 802.11a, b or g standards. When those messages are received at the second node, the message is injected back into the power line on the other side of a gap in power line coverage. This method of transmission backup will continue until power line connectivity is restore upon which the preferred method will be selected and used.

Communication is provided which includes receiving a transmitted radio signal at a powerline wherein the powerline functions as a receiving antenna for the wirelessly transmitted radio signal. The powerline is coupled to an input of a radio receiver using a coupler to communicate the radio signal to the radio receiver. For calibration purposes a second antenna not coupled to powerline may be used. A method for powerline communication across transformers, open circuit breakers, and other devices is also provided. In addition, a method of monitoring a device connected to a powerline is provided.

The present invention involves method and apparatus for analyzing two measured signals that are modeled as containing primary and secondary portions. Coefficients relate the two signals according to a model defined in accordance with the present invention. In one embodiment, the present invention involves utilizing a transformation which evaluates a plurality of possible signal coefficients in order to find appropriate coefficients. Alternatively, the present invention involves using statistical functions or Fourier transform and windowing techniques to determine the coefficients relating to two measured signals. Use of this invention is described in particular detail with respect to blood oximetry measurements.

Estimates of a communication system configuration, such as a DSL system, are based on operational data collected from a network element management system, protocol, users and/or the like. The operational data collected from the system can include performance-characterizing operational data that typically is available in an ADSL system via element-management-system protocols. Generated estimates and/or approximations can be used in evaluating system performance and directly or indirectly dictating/requiring changes or recommending improvements in operation by transmitters and/or other parts of the communication system. Data and/or other information may be collected using “internal” means or may be obtained from system elements and components via email and/or other “external” means. The likelihood of a model's accuracy can be based on various data, information and/or indicators of system performance, such as observed normal operational data, test data and/or prompted operational data that shows operating performance based on stimulation signals. One example of such prompted data uses frequency carrier masks to approximate the Hlog of a given channel, including information regarding bridged taps, attenuation, etc.

A system and method for canceling interference present in a code-division multiple access (CDMA) channel signal received at a CDMA receiver that is caused by multipath components of a transmitted pilot channel signal or by soft handoff conditions is computationally efficient because it operates at symbol rates. The channel signal from which such multipath interference is canceled can be either a traffic (data) channel or the pilot channel itself. Interference signals are produced in groups corresponding to the fingers of the CDMA rake receiver. The interference signals corresponding to each finger are used to cancel interference in the other fingers.

A system for providing an accurate prediction of a signal-to-interference noise ratio is described. The system includes a first circuit for receiving a signal transmitted across a channel via an external transmitter. A second circuit generates a sequence of estimates of signal-to-interference noise ratio based on the received signal. A third circuit determines a relationship between elements of the sequence of estimates. A fourth circuit employs the relationship to provide a signal-to-interference noise ratio prediction for a subsequently received signal. In the illustrative embodiment, the inventive system further includes a circuit for generating a data rate request message based on the signal-to-noise ratio prediction. A special transmitter transmits the data rate request message to the external transmitter. In the specific embodiment, the relationship between elements of the sequence of estimates is based on an average of the elements of the sequence of estimates. The third circuit includes a bank of filters for computing the average. The bank of filters includes finite impulse response filters. Coefficients of the transfer functions associated with each filter in the bank of filters are tailored for different fading environments. The different fading environments include different Rayleigh fading environments, one environment associated with a rapidly moving system, a second environment associated with a slow moving system, and a third system associated with a system moving at a medium velocity. A selection circuit is connected to each of the filter banks and selects an output from one of the filters in the filter bank. The selected output is associated with a filter having a transfer function most suitable to a current fading environment.

A monitoring system for a communications network includes a set of components for transmitting and receiving data signals over the communications network. Each component includes a built-in self-test system for performing tests within the component and outputting corresponding test results. Each self-test system is configured to non-invasively determine waveform characteristics of the data signals. The system includes a set of processors. Each processor is coupled to a subset of the set of components, and is configured to evaluate the test results output by the components coupled to the processor. Each processor is configured to detect and predict faults in the communications network based on the evaluation of the test results.

A method and an apparatus for data transmission in a mobile telecommunication system supporting an enhanced uplink service are provided. A Transport Format Combination (TFC) selector determines TF information for data to be transmitted through a first data channel not supporting Hybrid Automatic Repeat reQuest (HARQ) and a second data channel supporting HARQ, and determines gain factors for the first and second data channel, and first and second control channel carrying control information for the first and second data channel. The gain factors are input to a physical channel transmission controller, and the physical channel transmission controller reduces the gain factor for the second channel if total transmit power required for transmission of the channels exceeds the predetermined maximum allowed power. A gain scaler adjusts transmit powers of the channels using the scaled gain factor and gain factors for the first data channel, the first control channel and the second control channel.

A physical layer module (PHY) of a network device includes a control module and a cable-test module. The control module selectively generates a cable-test enable signal to test a cable including four pairs of twisted wire. The cable-test module tests the cable based on the cable-test enable signal. The cable-test module transmits test signals on the four pairs at a first time and receives return signals. The cable-test module determines that the cable is not faulty when the return signals received on first and second pairs of the four pairs have an amplitude less than a first predetermined amplitude, and when the return signals received on third and fourth pairs of the four pairs have an amplitude greater than a second predetermined amplitude and are received substantially contemporaneously.

Method and apparatus for determining a downlink channel response in an orthogonal frequency division multiplexing access (OFDMA) system. The method and apparatus uses the uplink quality indication channel for determining the downlink channel response, or uses round trip pilot relay channel sounding. The uplink quality indication channel may comprise modified mini-tiles. The subscriber station using round trip pilot relay channel sounding sends composite transponder pilots after receiving the DL pilots.

Detecting a linear impairment in a cable under test by using a random signal transmitted down the cable. The impairment causes a reflected signal to be combined with the random signal. The combined signal extends over a plurality of sub-bands. A method and apparatus perform the steps of: (a) receiving the combined signal from a test point upstream from the impairment; (b) tuning to each sub-band and receiving a part of the combined signal within each sub-band; (c) determining an autocorrelation function of each part of the combined signal of each sub-band, to produce a plurality of autocorrelation functions; (d) combining the autocorrelation functions to form a combined function; (e) detecting the reflected signal from the combined function; and (f) determining, from the combined function, a time delay associated with the reflected signal and the distance from the test point to the impairment.

Disclosed is an apparatus and method for adaptively allocating transmission power for beamforming combined with orthogonal space-time block codes (OSTBC) in a distributed wireless communication system, the apparatus comprising: a plurality of sub-arrays for beamforming, which are geographically distributed and each of which comprises a plurality of distributed antennas placed in random groups; and a central processing unit for identifying performances of subsets by applying a predetermined power allocation scheme according to subsets which can be obtained by combining the sub-arrays, by means of a Nakagami fading parameter and information about large-scale fading of each of the sub-arrays, fed back from a receiving party, for determining a subset having a best performance as an optimal subset according to the identified performances, and for performing power allocation based on the subset set as the optimal subset.

A fault detection apparatus according to an embodiment is provided with a measurement unit, a memory unit, a control unit, and a display unit. The measurement unit measures a first time period taken until a reflection signal reflected on a fault of a test apparatus is received after a first signal is transmitted to the test apparatus. The memory unit includes a CAD data unit having CAD data of the test apparatus, and a model data unit to store model data indicating a relation between the first time period and a predicted conduction distance of the first signal according to the CAD data. The control unit calculates a range of a test object selected in the test apparatus based on the CAD data, calculates the predicted conduction distance from the first time period based on the model data, and specifies a position of a fault of the test apparatus which is separated by the predicted conduction distance from the measurement unit in the range of the test object. The display unit displays the position of the fault in the CAD data.

The present invention provides a digital (computational) branch calibrator which uses a feedback signal sensed from an RF transmit signal path following the combining stage of LINC circuitry of a transmitter to compensate for gain and phase imbalances occurring between branch fragment signals leading to the combiner. The calibrator feeds a quiet (zero) base band signal through the transmit path during the calibration sequence (i.e. a period when data is not transmitted) and adjusts the phase and gain of the phasor fragment signals input thereto by driving the sensed output power to zero. The calibration is performed by alternating phase and gain adjustments with predetermined (programmable) and multiple update parameters stages (speeds). A baseband modulation is preferably used to distinguish false leakage (e.g. due to local oscillator, LO, feed through and DC offset in the base band Tx) from imbalance leakage.

A signal integrity network analyzer is provided. The analyzer preferably includes a characterization module for characterizing a device under test, an acquisition module for acquiring a waveform, a de-embedding module for selectively embedding and de-embedding on or more system fixtures, and an analysis module for performing analysis on the acquired waveform, with one or more system features selectively embedded or de-embedded. A single user interface is provided and is adapted to control the characterization module, the acquisition module, the de-embedding module and the analysis module.

Systems and methods for transceiver communication are discussed herein. An exemplary system comprises a first transceiver unit comprising a first attenuator, a filter module, a gain module, and an antenna. The first attenuator may be configured to attenuate a transmission signal from a second transceiver module over a coaxial cable. The transmission signal may comprise a primary component and a triple transit component. The first attenuator may further be configured to attenuate and provide a reflection signal over the coaxial cable to the second transceiver module. The reflection signal may be based on a reflection of at least a portion of the transmission signal. The filter module configured to filter the transmission signal. The gain module may be configured to increase the gain of the transmission signal. The antenna may be configured to transmit the transmission signal.

Systems and methods for receiving an OFDM preamble without knowledge of channel characteristics are provided. An OFDM preamble signal with frequency shifted cyclic extensions is received. Taken together the cyclic extensions form a frequency shifted version of the OFDM preamble signal. Frequency offsets and timing offsets are estimated and corrected in an efficient manner using a simple concatenation approach in the time domain, followed by a summation of the OFDM preamble signal and the concatenation after a transformation of the OFDM preamble and the concatenation into the frequency domain. Phase errors in the frequency domain are estimated and corrected after FFT transformations of the received signals. A valid preamble is detected and additional parameters for receiving subsequently transmitted OFDM symbols in a channel are extracted from the OFDM preamble. The methods are computationally efficient and robust. Receiver implementations for performing the methods in a DVB receiver are disclosed.

An apparatus for transmitting information comprises a bitstream source for providing a bitstream representing the information, a redundancy adding encoder for generating an encoded bitstream, which is arranged to output, for a first number of input bits, a second number of output bits, the second number of output bits having at least twice as many output bits as the first number of input bits, wherein the second number of output bits includes two portions of output bits, each portion of output bits individually allowing the retrieval of information represented by the first number of input bits, and the first portion of output bits being coded based on the bitstream in a different way with respect to the second portion of output bits. The apparatus further comprises a partitioner for partitioning the second number of output bits into the two portions of output bits and a transmitter for transmitting the output bits of the first portion via a first channel and the output bits of the second portion via a second channel, the second channel being spatially different from the first channel. An inventive receiving apparatus combines the signals received via the first and second channels and uses both channel signals for channel decoding by removing redundancy. Thus, the transmitting receiving system is suitable for providing time and/or space diversity and, in the optimal case, provides a C/N value which is greater than 4.3 dB with respect to a two-channel system comprising a duplicator in the transmitter and a channel-controlled switch in the receiver.

A method and apparatus for pilot-symbol aided channel estimation in a wireless digital communication system which transmits packets of N OFDM data blocks, each data block comprising a set of K orthogonal carrier frequencies. At the transmitter, pilot symbols are inserted into each data packet at known positions so as to occupy predetermined positions in the time-frequency space. At the receiver, the received signal is subject to a two-dimensional inverse Fourier transform, two-dimensional filtering and a two-dimensional Fourier transform to recover the pilot symbols so as to estimate the channel response.

Controlling margins in a DSL modem pair is based on collected operational data. The operational data is analyzed and at least one of the modems in the modem pair is instructed to use a margin-related parameter value to assist the modem pair in meeting a margin target, such as a margin limit imposed by a DSL standard or the like. A controller, such as a DSM Center, a “smart” modem unit and/or a computer system can collect and analyze the operational data and generate one or more margin-related parameter values. The margin-related parameter value may be a PSD-related value, such as the MAXNOMPSD, MAXNOMATP or PSDMASK parameter used by various ADSL systems, and may be a shaped spectral mask and/or caps or limits on bit loading for use in transmissions between the modems. In some cases, preference bands can be imposed to direct modems to favor and/or avoid certain frequencies in the modem's usable band(s). The operational data may include historical data relating to prior performance of the modem pair and prior margin compliance. A distribution of margins also may be based on operational data and may be estimated as a function of data rate. Using the estimated margin distribution, a distribution of performance parameters also is calculated, including the probabilities of line outages and probabilities of one or more error parameters exceeding minimum levels. Data rates and/or performance-related parameters may be set on the basis of the estimated performance of the system using various margin settings and levels.

Disclosed are the design and implementation of a CSI feedback channel in a multi-carrier wireless communication system. An apparatus and a method for channel state feedback using arithmetic coding are provided to ensure efficiency and reliability of a system by transmitting the CSI while compressing the CSI with a predetermined compression rate selected depending on a channel state. The apparatus for CSI feedback in a wireless communication system performing channel estimation at a transmitter or a receiver by using a communication channel includes a transmitter terminal transmitting a signal for CSI measurement by using the communication channel, and a receiver terminal receiving the signal from the transmitter terminal, checking a channel state based on the received signal, and transmitting the signal to the transmitter terminal after compressing the signal according to the channel state.