Abstract: To evaluate an energy level of a signal received through a radio interface between radiocommunication stations, successive measurement samples depending on the energy of the signal are obtained, and an average of said samples is calculated, to evaluate the energy level. The calculation of the average of the samples is performed with an averaging duration depending on a service to which the received signal pertains.

Abstract: Embodiments related to FEXT estimation and signaling in vectored systems are described and depicted herein.

Abstract: The present invention overcomes various problems by defining two upstream masks (U1, U2) and two downstream masks (D1, D2) and using a mask selectable system for the long reach digital subscriber line (LDSL), in which a unique modem feature is activated during handshake to automatically check for physical layer status in terms of spectral compatibility and, thus, automatically optimize the boosted mode with the use of the mask selectable system choose the best combination of upstream/downstream masks in any physical layer noise scenario.

Abstract: Systematic transmit IQ phase and amplitude imbalances in the transmit chain of a wireless local area network (WLAN) cause a corresponding systematic shift in the roots of a constellation diagram. Additional random phase noise in the transmit chain will cause a further Gaussian distribution of points in the constellation diagram about the systematically shifted roots. This random distribution represents a true error vector magnitude (EVM). By transmitting a known training sequence through the transmit chain, which it is known will be shifted to all of the systematically shifted roots in the constellation diagram, the Gaussian spread around those shifted roots can be analysed to determine the true EVM.

Abstract: Embodiments of the invention provide time-domain link adaptation in power line communications. In one embodiment, the cyclic prefix length and position is adjusted with an OFDM symbol to overlap a periodic impulse noise pulse, thereby allowing the data carried in the symbol to be detected at a receiver. The cyclic prefix may be adjusted to provide a pattern that yields an integer number of OFDM symbols in one zero crossing period. The data rate used for the symbols overlapping the zero-crossing period may be zero or very low. A high data rate may be used for symbols outside the zero-crossing period because those symbols will not be affected by the periodic impulse noise.

Abstract: The invention concerns receive circuitry for demodulating an input signal received from a transmission channel, the receive circuitry having a decision feedback equalizer (228) including an inter-carrier interference estimation block (324) arranged to provide an estimation (RICI(n)) of inter-carrier interference (ICI) noise based on at least a channel estimation (?STAT(n?1)) determined for a previous symbol, a channel estimation (HSTAT(n+1)) determined for the next symbol, and on a previous estimation (?i?1(n)) of the symbol data for the current symbol, the previous estimation being provided by a feedback path comprising a demapping block (314); and correction circuitry (310, 312, 314, 316) arranged to determine the estimation of the original data signal based on the estimation of ICI noise subtracted from the input signal.

Abstract: A method for multiple-input multiple-output (MIMO) collaborative communication in a wireless communication system includes at least one user equipment and M base stations performing collaborative communication with the user equipment. Here, M is an integer that is greater than or equal to 2. The method includes the following processes for each user equipment: a first level of MIMO pre-coding process is performed for each base station to acquire each first level of pre-coding matrix corresponding to each base station; a second level to the X-th level of MIMO pre-coding process is performed sequentially to acquire the second level to the X-th level of pre-coding matrices of the corresponding base stations. Here, X is an integer that is greater than or equal to 2. A pre-coding device, a user equipment and a wireless communication system related to the method are also provided.

Abstract: A technique weights noise power used in a demodulation/demapping process using on an estimate of interference and its associated power. Using this technique the effect of partial interference can be ameliorated. For example, a value, ?2, can be used to represent the estimated noise and interference power, and ?2 can be used to modify a received signal to ameliorate the effects of noise and interference. ?2 can be adjusted in response to partial interference, and can be represented by the formula: ?2=?N2+q ?I2, where ?N2 is “noise power,” ?I2 is “interference power,” and q is an interference correction factor.

Abstract: Methods and apparatus for gathering information about the eye of a high-speed serial data signal include sampling each bit of a repeating, multi-bit data pattern at several eye slice locations. For any given eye slice location, each bit in the data pattern is compared in voltage to a base line reference signal voltage to establish a reference value for that bit. Then the reference signal voltage is gradually increased while the voltage comparisons are repeated until for some bit a result of the comparing is different than the reference value for that bit. This establishes an upper value for the eye at the eye slice location. The reference signal voltage is then gradually decreased to similarly find a lower value for that eye slice.

Abstract: There is provided a method for transmitting channel quality information in a wireless communication system. Over-all band of the wireless communication system is divided by a plurality of sub-bands. The method includes selecting a first sub-band having the highest CQI among the plurality of sub-bands, transmitting CQI of the first sub-band and transmitting CQI of a second sub-band, the second sub-band having the CQI lower than the first sub-band, wherein the number of CQI levels of the second sub-band is less than that of CQI levels of the first sub-band. Overheads incurred by CQI feedback can be reduced.

Abstract: Techniques to facilitate estimating the frequency response of a wireless channel in an OFDM system are provided. The method and systems allow for combining signal information across multiple communication channels at one or more channel tap delays in order to determine appropriate taps for channel information.

Abstract: A wireless communication method and system using virtual MIMO (“V-MIMO”) are provided. Post processing signal to interference and noise ratios (“SINR”) for a plurality of signals corresponding to a plurality of mobile terminals arranged as a V-MIMO group are estimated. The one of the plurality of mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected mobile terminal is scheduled. The signal corresponding to the selected mobile terminal is cancelled. Post processing signal to interference and noise ratios (“SINR”) for the signals corresponding to the remaining mobile terminals is re-estimated. The one of the remaining mobile terminals having the highest post processing SINR is selected. Wireless communication for the selected remaining mobile terminal is scheduled.

Abstract: An embodiment of the invention relates to a method of determining an optimum sequence of algorithms, wherein each algorithm defines a receiver function of a receiver, which has a plurality of receiver functions and which is adapted to receive bits sent by a transmitter.

Abstract: A quantization method of transmission of channel quality information (CQI) includes measuring two measurements SINRs and calculating a difference (i.e., Delta SINR) between the two measurements of the SINRs; determining a CQIbase (base channel quality information) based on one of the two measurements SINRs and a known quantization table for the CQIbase, and simultaneously receiving cell-specific or UE-specific parameters transmitted from a base station and configuring a quantization table defining a mapping method of CQIdelta (delta channel quality information) and the Delta SINR and determining the CQIdelta based on the obtained Delta SINR and the configured quantization table; and transmitting the resulting CQIdelta and CQIbase.

Abstract: Systems and methods of detecting wireless channel status from acoustic discrimination of spectral content are described. In one aspect, a wireless system includes a spectrum analyzer, a detector, and a controller. The spectrum analyzer is operable to acoustically discriminate spectral content of an input electrical signal in multiple discrete frequency channels. The detector is operable to determine respective statuses of the frequency channels from the acoustically discriminated spectral content. The controller is operable to select one of the frequency channels based on the determined statuses of the frequency channels.

Abstract: Provided are a fixed station receiver for a Multi-Input Multi-Output (MIMO) communication system and an uplink adaptation method thereof. In the uplink adaptation method, a sounding reference signal (SRS) is received from a terminal including a plurality of transmission antennas. A complex channel matrix (H) corresponding to a channel response and a noise variance (?2) corresponding to a noise power is calculated from the sounding reference signal. A signal-to-interference and noise ratio (SINR) on each transmission symbol is calculated with reference to the complex channel matrix (H) and the noise variance (?2). A pre-coding matrix of the terminal is selected with reference to the signal-to-interference and noise ratio (SINR).

Abstract: A digital circuit configured to spread a clock train spectrum includes a clock configured to generate the clock train, and a variable divider configured to divide the frequency of the clock train by a temporally-varying-divider value to modulate the clock train and generate a dithered clock train. The circuit further includes a first accumulator configured to accumulate the dithered clock train to generate a frequency modulation waveform, and a second accumulator configured accumulate the frequency modulated waveform to generate a phase modulation signal. The circuit further includes a phase-value calculator configured to calculate the temporally-varying divider value based on the phase modulation signal; and a closed-loop control circuit configured to track and filter the modulation of the dithered clock train to generate a second clock train that is the spread spectrum of the first mentioned clock train.

Abstract: In one aspect, a method to simulate performance of a communication system includes providing a list of interference components to a user, receiving from the user selections of interference components from the list of the interference components, performing an analysis based on the user selections of the interference components and rendering a result of the analysis.

Abstract: A system and method for modulating and amplifying an input signal are provided in a communication transmitter. The transmitter includes a pre-distortion lookup table containing pre-distortion lookup data. An auto-calibration module is in communication with the pre-distortion lookup table. The auto-calibration module is configured to operate during a closed-loop auto-calibration interval and to calibrate the pre-distortion lookup data to compensate for a non-linearity in the transmitter. The pre-distortion is based on the pre-distortion lookup data and is used during an open-loop operational interval.

Abstract: The present invention relates to a precoder for a communication system arranged to provide transmission blocks for transmission over a transmission channel based on inputted symbol blocks. The precoder is arranged to pre-distort each symbol block based on an estimate of the characteristics of the transmission channel so that the corresponding transmission block appears to be undistorted after transmission over the transmission channel. In accordance therewith, the precoder is arranged to apply Tomlinson-Harashima precoding on a sum of a first measure corresponding to predistortion so as to remove intrasymbol interference and a second measure corresponding to predistortion so as to remove intersymbol interference. The present invention further relates to a method for providing transmission blocks for transmission over a transmission channel in a communication system.

Abstract: The current invention relates to a method of determining a quality of a received signal, wherein the method comprises receiving a signal comprising a first part and a second part and wherein at least the second part of the received signal comprises a scrambling sequence period; and determining a first noise-and-interference power of the first part of the received signal by removing a second noise-and-interference power of the second part of the signal, wherein the scrambling sequence period is utilized in the removal. The invention further relates to a corresponding device and system. Thereby, the invention is able to, among other things, reduce neighbor cell reference symbol interference in a dense network.

Abstract: An interference classifier is disclosed for determining the type of interference present in a signal. The interference classifier 601 comprises a buffer 602 operable to receive and store data comprising samples of a signal; a scale factor calculator 603 operable to use the signal samples to calculate a scale factor in dependence upon the levels of the signal samples; a normaliser 604 operable to calculate normalised signal samples by using the scale factor to normalise the signal samples; a nonlinear transformer 605 operable to perform a nonlinear transform on the normalised signal samples to calculate transformed signal samples; an averaging circuit 606 operable to calculate an average of the transformed signal samples; and a comparator 607 operable to compare the calculated average of the transformed signal samples to a predetermined threshold level in order to determine the type of interference present in the received signal.

Abstract: Systems and methods are disclosed for detecting temporary high level impairments, such as noise or interference, for example, in a communications channel, and subsequently, mitigating the deleterious effects of the dynamic impairments. In one embodiment, the method not only performs dynamic characterization of channel fidelity against impairments, but also uses this dynamic characterization of the channel fidelity to adapt the receiver processing and to affect an improvement in the performance of the receiver. For example, in this embodiment, the method increases the accuracy of the estimation of the transmitted information, or similarly, increases the probability of making the correct estimates of the transmitted information, even in the presence of temporary severe levels of impairment. The channel fidelity history may also be stored and catalogued for use in, for example, future optimization of the transmit waveform.

Abstract: A method limits the effect of repetitive electrical impulse noise in a communication system. The presence of the repetitive electrical impulse noise is detected during communication service. If the repetitive electrical impulse noise is detected, then a message is transmitted which signals that the repetitive electrical impulse noise is present. Other systems and methods are disclosed.

Abstract: A signal generator generates a WiMedia ultra wideband test signal with a user interface for setting test sequences and parameters of the test signal. Parameters are set for Presentation Protocol Data Units associated with Packet Groups of the test signal. A signal processing unit compiles the Groups containing the Presentation Protocol Data units to generate digital data representative of the test signal. A waveform generator receives the digital data and generating a test signal output having Packet Groups containing Presentation Protocol Data Units. A method is describes for setting test sequences and parameters of an ultra wideband test signal test signal with a user interface of the signal generator.

Abstract: Channel quality metrics (such as SINR, BLER, and the like) are derived from a raw bit error rate (RBER), defined as the error rate of raw bits output by a demodulator. These initial raw bits are decoded and error-checked (or error-corrected). The error-free decoded bits are re-encoded, and the regenerated raw bits are compared to the initial raw bits to determine the RBER. The RBER is then converted to SINR, BLER, or other channel quality metric. The RBER-based metrics are derived from a data channel rather than reference signals, and hence more accurately reflect deviations from nominal transmission power level, and include receiver demodulator impairments.

Abstract: There is provided an apparatus for determining a carrier-to-noise power density ratio (CN0) of a spread spectrum signal. The apparatus includes a signal power calculation unit and a conversion unit. The signal power calculation unit determines a signal power indicator indicative of a signal to noise ratio of the spread spectrum signal. The conversion unit is coupled to the signal power calculation unit and stores a lookup table representing a relationship between the signal power indicator and the carrier-to-noise power density ratio. The conversion unit is operable for converting the signal power indicator to the carrier-to-noise power density ratio according to the lookup table.

Abstract: A multipath discriminator module and related methods are provided for communications and/or navigation systems that implement spread spectrum modulation. In one example embodiment, the module includes an input suitable for receiving navigation signals, a sampler for supplying sampled signals at a frequency twice the apparent frequency of the code of the signals, and a submodule for calculating an error signal from the sampled signals.

Abstract: A receive signal processor jointly detects two or more symbols in a signal-of-interest in the presence of one or more other MIMO signals. The signal-to-interference-plus-noise ratio for each signal-of-interest is determined by computing per-subcarrier signal-to-interference-plus-noise ratios for a plurality of subcarriers allocated to the signals-of-interest, and computing a total signal-to-interference-plus-noise ratio for the subcarriers based on the per-subcarrier signal-to-interference-plus-noise ratios of the subcarriers. A controller determines one or more transmission formats for uplink transmissions based on the signal-to-interference-plus-noise ratios. The process of computing per-subcarrier signal-to-interference-plus-noise ratio reflects the amount of MIMO interference already cancelled or still remaining in the signal arriving at the joint detector.

Abstract: Techniques to process data for transmission over a set of transmission channels selected from among all available transmission channels. In an aspect, the data processing includes coding data based on a common coding and modulation scheme to provide modulation symbols and pre-weighting the modulation symbols for each selected channel based on the channel's characteristics. The pre-weighting may be achieved by “inverting” the selected channels so that the received SNRs are approximately similar for all selected channels. With selective channel inversion, only channels having SNRs at or above a particular threshold are selected, “bad” channels are not used, and the total available transmit power is distributed across only “good” channels. Improved performance is achieved due to the combined benefits of using only the NS best channels and matching the received SNR of each selected channel to the SNR required by the selected coding and modulation scheme.

Abstract: Disclosed is a receiver, such as an orthogonal frequency-division multiplexing (OFDM) receiver, including two or more receiver chains. Each of the receiver chain may include an antenna, down converting circuitry and time to frequency converting circuitry, and the two or more chains may be adapted to operate in concert so as to receive substantially the same signal substantially concurrently. Signal processing circuitry may be adapted to constructively combine signals received at the two or more receiver chains into a unified signal. Selection logic may be adapted to select a mode of signal combination by the signal processing circuitry, wherein the selection logic may be adapted to instruct the processing circuit to either combine two or more received signals into a single received signal or to use only one of the two or more received signals for further processing.

Abstract: In the power saving, a method for saving power at a receiver of a mobile communication system includes acquiring Carrier to Interference plus Noise Ratio (CINR) and Modulation and Coding Scheme (MCS) information required by the receiver; determining the number of Least Significant Bits (LSBs) to hold based on the CINR and MCS information; and holding LSBs of the determined number of the bits in received information.

Abstract: To synchronize symbol timing in a communication system, time-domain signals are generated by performing an IFFT on frequency-domain signals. Positions of power peaks are detected by analyzing a channel impulse response (CIR) of the time-domain signals. Channel state informations are provided by analyzing a channel state, such that each channel state information corresponds to each position of the power peaks. A proper symbol start position is determined based on the channel state informations.

Abstract: A wireless communication device, a wireless communication system and a method to adjust transmitted signals constellation in a maximum likelihood multiple-input-multiple-output receiver by transmitting an EVM deviation value. The EVM deviation value may be added to a pre-stored error value at the receiver.

Abstract: One embodiment of the present invention relates to a method of monitoring impulse noise. In the method, clusters of corrupted symbols in a stream of symbols are characterized in accordance with a cluster parameter associated with the clusters. Other methods and systems are also disclosed.

Abstract: Provided is a communication apparatus which calculates a CQI indicating reception quality of a reception signal in a receiver and feeds back the CQI to a transmitter, the CQI containing information obtained by averaging SNRs of a plurality of subbands, which are generated by dividing a reception band into a predetermined number, in the reception band, the communication apparatus including a CQI/PMI/RI estimation unit directly uses an initial value in a predetermined approximation method as an approximation calculation result obtained by the predetermined approximation method to thereby simplify the calculation, when the predetermined approximation method is used for calculation in the averaging in place of root calculation and when values of the SNRs are high.

Abstract: A wireless communications apparatus that it is useable as a spectrum analyzer and as a wireless receiver. The wireless communications apparatus has a radio circuit that is configured to receive EM radiation. Signal processing logic receives signals from the radio circuit based on the EM radiation. The signal processing logic has a receiver operational mode that processes the signals in accordance with a communication protocol and outputs data encoded in the signals to a host processor. The signal processing logic has a spectrum analyzer operational mode that generates frequency domain data and passes the frequency domain data to the host processor. The frequency domain data describe strength versus frequency of the EM radiation. The host processes the data in accordance with the configuration currently in use. Therefore, the wireless communications apparatus operates as a receiver in one operational mode and as a real-time spectrum analyzer in another operational mode.

Abstract: An apparatus and method for estimating a Carrier-to-Interference and Noise Ratio (CINR) in a communication system are provided.

Abstract: An SIR estimate of a communication signal in a wireless communication system receiver is calculated based on soft bit values output by a nonlinear detector. The average amplitude of the detector output soft bits is estimated. The average power of the detector output soft bits is estimated, e.g., as a mean-square or variance. An SIR of the communication signal is estimated based on the soft bit amplitude and power estimates. In particular, the SIR is estimated as the ratio of the square of soft bit amplitude to the difference between the mean square soft bit power and the square of soft bit amplitude, or the ratio of the square of soft bit amplitude to the variance. In either case, the SIR estimate may be scaled to obtain the desired units. The communication signal may be a received signal, or a simulated signal generated using channel estimates obtained from, e.g., a pilot channel.

Abstract: A method of analyzing the performance of a modem connection. The method includes connecting a line interface to a communication link carrying signals of a modem connection, between a pair of end modems, collecting signals passing on the communication link, between the end modems, through the line interface, determining quality or transmission characteristics regarding the modem connection, responsive to signals collected through the line interface, and displaying information on the determined characteristics.

Abstract: A method and apparatus for improving performance in communication systems is provided. In one implementation, information is accessed indicating the quality of at least one communication channel. Based on the accessed information, a modulation scheme is indicated for sending data over the channel encoded with a rateless code. Various different information relating to the communication channel can be used to determine a quality metric for the channel.

Abstract: Techniques for selecting rates for data transmission on eigenmodes of a MIMO channel are described. An access point transmits an unsteered MIMO pilot via the downlink. A user terminal estimates the downlink channel quality based on the downlink unsteered MIMO pilot and transmits an unsteered MIMO pilot and feedback information via the uplink. The feedback information is indicative of the downlink channel quality. The access point estimates the uplink channel quality and obtains a channel response matrix based on the uplink unsteered MIMO pilot, decomposes the channel response matrix to obtain eigenvectors and channel gains for the eigenmodes of the downlink, and selects rates for the eigenmodes based on the estimated uplink channel quality, the channel gains for the eigenmodes, and the feedback information. The access point processes data based on the selected rates and transmits steered data and a steered MIMO pilot on the eigenmodes with the eigenvectors.

Abstract: A method, apparatus, and computer-readable medium for basis selection is described. A plurality of sub-bands of digital data is generated and a basis function for the digital data in one of the plurality of sub-bands is determined at a rate that provides a substantially peak signal-to-noise ratio for the digital data. The basis function is added to a codebook and the digital data is compressed using the codebook.

Abstract: A method for estimating a Signal to Noise Ratio (SNR) in a received signal including, for a fixed first set of a plurality of samples from the received signal, providing an initial noise estimate, starting with the initial noise estimate, iteratively improving the noise estimate, and estimating SNR based, at least partly, on the fixed first set of samples from the received signal and the noise estimate. Additional related apparatus and methods are also described.

Abstract: An apparatus and a method for estimating a Noise and Interference (NI) power in a communication system are provided. The method includes, calculating average values of impulse responses according to ranging codes, through use of a ranging signal sequence received through a resource allocated to a ranging channel, arranging the average values of the impulse responses according to ranging codes in order of the highest value to the lowest value, and multiplying a ranging code, which corresponds to an impulse response having an (x+1)th peak value among the arranged average values of the impulse responses, by a specific threshold value, and estimating the NI power, wherein “x” represents a number of ranging codes which can be simultaneously received by one ranging channel.

Abstract: The present invention relates to code-dependent bit interleavers for parallel non-uniform channels. Since the channel dependence of a given code ensemble is dominated by the mutual information between the channel input and output, the present invention proposes to simplify the analysis about the decoding behavior by using a set of surrogate binary erasure channels. The approximation of the actual channel by the surrogate BEC is established on the equivalence of bitwise capacities, which represent the mutual information between the uniformly-distributed binary input and the likelihood ratios of the effective parallel AWGN channels. Moreover, the transition of the erasure probabilities is modeled by a linear difference equation around the decoding threshold SNR, from which we can derive a necessary condition on the convergence of decoding iterations and achieve a useful guideline for the configuration of the bit interleaver.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for identifying network events. In one aspect, a method includes monitoring signal characteristic values for signals transmitted over a communications channel of a power line communications system and determining that a signal level value for the channel is less than a threshold signal level value for the channel. In response to determining that the signal level value for the channel is less than the threshold signal level value for the channel, computing a signal to noise ratio for the communications channel and determining that the signal to noise ratio for the channel exceeds a threshold value. In response to determining that the signal to noise ratio for the communications channel exceeds the threshold value, storing data received over the communications channel as valid data.

Abstract: A rate-adaptive method of communicating over a multipath wireless communication system uses multiple links such that each end of a link uses multiple transmit and receive antennas. A number of independent streams that are to be transmitted for each link is determined based on an overall system performance measure. In addition, the system may also jointly determine the best modulation, coding, power control, and frequency assignment for each link, based on an overall system performance measure. In OFDM systems, the number of independent streams, as well as the modulation, coding, and power control, may be determined on a tone-by-tone basis based on an overall system performance measure.

Abstract: Aspects of a method and system for dynamic adaptation and communicating differences in frequency-time dependent systems may include generating a time difference weighting factor and a frequency difference weighting factor, based on at least channel estimates. A time-frequency difference may be computed by forming a weighted sum comprising a time difference and a frequency difference, where forming the weighted sum uses at least the time difference weighting factor and the frequency weighting factor. A channel quality indicator (CQI) feedback message may be generated, comprising the time-frequency difference. The time difference weighting factor and/or the frequency difference weighting factor may be generated adaptively at a base station or a mobile terminal. The time difference and/or the frequency difference may be generated from estimated Signal-to-Noise-Ratios (SNRs) associated with the channel estimates. The SNRs may be based on at least the output of an MMSE receiver.

Abstract: A receiver of a spatially multiplexed multiple input multiple output (SM MIMO) system divides the SM MIMO system into a plurality of virtual single input multiple output (SIMO) systems by using the estimated channel, calculates losses generated by the plurality of streams received through the plurality of reception antennas, and predicts an SINR of each stream by using the losses and the capacities of the plurality of virtual SIMO systems. It is possible to more accurately estimate the performance of a maximum likelihood (ML) detector or the performance of a detector showing the performance of a maximum likelihood (ML) detection mechanism by using the estimated SINR of each stream.