Abstract: Evaluation of the impact of impulse noise on a communication system can be utilized to determine how the system should be configured to adapt to impulse noise events. Moreover, the system allows for information regarding impulse noise events, such as length of the event, repetition period of the event and timing of the event, to be collected and forwarded to a destination. The adaptation can be performed during one or more of Showtime and initialization, and can be initiated and determined at either one or more of a transmitter and a receiver.

Abstract: A signal receiver apparatus includes a waveform shaping data storage device storing waveform shaping data of a signal transmitted with a given timing from a signal transmitter device of a plurality of signal transmitter devices which are coupled to the signal receiver apparatus for each of the plurality of signal transmitter devices, and a waveform shaping device reading waveform shaping data of the signal transmitter device in the plurality of signal transmitter device from the waveform shaping data storage device when a signal from the signal transmitter device is received, and shaping a waveform of a received signal from the signal transmitter device.

Abstract: Methods of controlling a transmission power and configuring a codebook in a multi-antenna system to solve a transmission power unbalance between antennas are disclosed. The method of transmitting data in a multi-antenna system includes (A) transmitting one or more pilot signals within a first symbol region through a first antenna unit, and (B) transmitting one or more pilot signals within a second symbol region through a second antenna unit, wherein data within the first symbol region is transmitted through the second antenna unit, and data within the second symbol region is transmitted through the first antenna unit. According to the present invention, since a transmission power unbalance between antennas is solved, a transmission power can be uniformly assigned to each antenna and channel estimation can be easily performed. Moreover, a power amplifier having a uniform amplification range can be used and designed.

Abstract: The present disclosure provides a receiving device including, a receiver configured to receive a signal that is transmitted via a propagation path and is modulated by a predetermined system prescribed by a predetermined standard, a demodulator configured to demodulate a received signal, an estimator configured to estimate a signal-to-noise ratio relating to the propagation path, obtained from a data signal included in the demodulated received signal, and a corrector configured to correct an estimated signal-to-noise ratio in accordance with a transmission parameter obtained from the received signal.

Abstract: An adaptive time delay control system is provided for matching the propagation time delay between two samples of a signal traveling through two independent paths so that they can be coherently combined for additional signal processing functions such as cosite interference cancellers, adaptive interference cancellers and adaptive beam formers. The adaptive time delay control system and associated method advantageously provide improved continuous matching of the two channels over a wider adjustment range while preserving both convergence speed over the full range and minimum jitter upon convergence by using composite autocorrelation functions to control (adjusting) a matching time delay in one channel.

Abstract: Disclosed are data transmission/reception apparatus and method that may be applied to a case where additional data is to be transmitted in a CE-OFDM modulation/demodulation scheme that satisfies an OFDM feature which is robust against multipath fading and simultaneously has a feature that amplitude is constant. Service channel information, modulation parameter information of a physical layer, and the like, may be transmitted by using an additionally secured information channel. If using this, a service search time may be saved, and power of a receiver may be reduced.

Abstract: A method (300) for performing dual carrier modulation (DCM) precoding. The method comprises generating data sub-blocks (S320), independently interleaving the sub-blocks (S330), generating bit vectors by grouping bits of the interleaved sub-blocks (S350), mapping the bit vectors into data symbols (S360), and precoding the data symbols using a precoding matrix to generate precoded symbols (S370).

Abstract: Methods and systems that enable the determination of accurate channel estimates by measuring only power values of pilot signal transmissions at a receiver are described. Various measurement procedures that are based on average power measurements or short term, per-symbol measurements can be employed. Furthermore, procedures utilizing adaptive pilots generated with receiver feedback and deterministic pilots generated without receiver feedback are also described.

Abstract: A method and system for pre-distorting dual band signals to compensate for distortion of a non-linear power amplifier in a radio transmitter are disclosed. According to one embodiment, a first signal in a first frequency band and a second signal in a second frequency band are pre-distorted according to first and second pre-distortion function, respectively, the first and second pre-distortion functions being the dual of one another.

Abstract: An adaptive beam steering control system suitable for multiple element systems is provided for coherently forming a beam and tracking a dynamic scenario of a rapidly fading environment. The adaptive beam steering control system and associated method advantageously provide improved continuous beam steering with a faster response time and higher precision than normally attainable by using the greater slope of the nulling error function to perform the beam steering function. Although reciprocity of nulling and beam steering is normally only true for a single pair of elements, the method of the invention extends the process to larger arrays of elements.

Abstract: Provided is a transmitter which is small in size and operates with high efficiency and compensates a delay error with high accuracy. A signal generation section 11 outputs a PM test signal and an AM test signal. The AM test signal is inputted to a multiplier 16 via a delay adjustment section 12 and a regulator 14. The PM test signal is inputted to the multiplier 16 via the delay adjustment section 12. A power measurement section 17 measures an average power of a multiplication signal which is outputted from the multiplier 16 and outputs a measured value to a control section 18. The control section 18 determines an amplitude delay time and a phase delay time on the basis of the inputted measured value and sets the determined delay times in the delay adjustment section 12.

Abstract: A method for accessing aircraft interference path loss in an aircraft. A plurality of radio frequency signals that are stepped through a plurality of frequencies in a frequency range is transmitted from a plurality of locations within an interior of the aircraft. Radio frequency signals present at a receive antenna are received in response to transmitting the plurality of radio frequency signals to form a plurality of measurements. An average of averages curve is generated from the plurality of measurements. A peak to average ratio is identified. Field uniformity is identified. A standard error for the average of averages curve is determined. An upper bound for the aircraft interference path loss in the aircraft is predicted using the average of averages curve, the peak to average ration, the field uniformity, and the standard error.

Abstract: A method for estimating timing in a wireless communication comprises the steps of receiving a plurality of symbol bursts corresponding to a plurality of time slots and selecting a subset of symbols from a first symbol burst of the plurality of symbol bursts. The subset comprises a first midamble symbol. The method further comprises the steps of calculating, for each symbol in the subset, a corresponding midamble estimation error, and determining the lowest calculated midamble estimation error to determine a timing for the first symbol burst. The method further comprises the steps of processing the first symbol burst utilizing the timing determined for the first symbol burst, and processing a second symbol burst of the plurality of symbol bursts utilizing the timing determined for the first symbol burst.

Abstract: Systems and methods that provide clock jitter compensation architectures that improve the performance of direct radio frequency (RF) receivers by injecting a calibration tone into the received radio frequency (RF) signals in order to help identify and then compensate for the clock jitter noise. After injecting the tone, the jitter noise going through the direct RF bandpass sampling receiver is estimated using a narrow bandwidth filter, and the received signals are further processed and demodulated depending on the Nyquist zone of the received signal. The relative modulation factor for the modulation is computed and then applied to the Nyquist zone to de jitter that particular Nyquist zone.

Abstract: A device (100, 200) and a method is provided for processing a signal. The device comprises a filter unit 5 (101, 201); an FFI unit (102, 202) operatively connected to the filter unit and being located after the filter unit along a signal path for the signal; and a compensation unit (103, 203) operatively connected to the FFI unit and being located after the FFT unit in the signal path. The compensation unit is adapted to compensate for attenuation of the signal, which has been caused by the filter unit.

Abstract: Power amplifiers (PAs) using a Doherty or other power output level sensitive configuration have been employed for several years in telecommunications (as well as other applications) to take advantage of efficiency gains. For many of these applications, baseband signals are predistorted to compensate for nonlinearities in the PAs, but because there is a “switching event” in a Doherty-type amplifier (for example), the nonlinearities become dynamically varying. As a result, digital predistortion (DPD) becomes increasingly difficult to perform. Here, DPD modules are provided that adapt to changes in dynamically varying PAs based on a determination of the average power or other relevant metric prior to transmission.

Abstract: A method of operating a radio-frequency (RF) circuitry and a signal-processing circuitry in a mobile telephone apparatus includes at least partially disabling the signal-processing circuitry while transmitting or receiving signals. In one example, a processor is efficiently disabled by generating and servicing an interrupt of relatively high priority. One advantage of this example is that preexisting, legacy code can be maintained, while still achieving the desired objectives. The processor can be enabled by generating and servicing a second high priority interrupt.

Abstract: A circuit and method perform adaptive spectral enhancement at a frequency ?1 (also called “fundamental” frequency) on an input signal y which includes electromagnetic interference (EMI) at an unknown frequency, to generate a fundamental-enhanced signal ?1 (or its complement). The fundamental-enhanced signal ?1 (or complement) is thereafter used in a notching circuit (also called “fundamental notching” circuit) to generate a fundamental-notched signal y??1. The fundamental-notched signal y??1 is itself enhanced to generate a harmonic-enhanced signal ?2 that is used to notch the fundamental-notched signal y??1 again, in one or more additional notching circuits that are connected in series with the fundamental notching circuit. The result (“cascaded-harmonic-notched” signal) is relatively free of EMI noise (fundamental and harmonics), and is used as an error signal for an adaptation circuit that in turn identifies the fundamental frequency ?1.

Abstract: Various exemplary embodiments of this disclosure provide parallel to serial conversion apparatuses that includes a bit-swapping circuit that generates bit-swapped parallel data by swapping bits of input parallel data, and a parallel to serial conversion circuit that acquires M1 and M2 bits of the bit-swapped parallel data in a first and a second mode, respectively. The parallel to serial conversion circuit generates serial data by arranging the acquired bits of the bit-swapped parallel data in a first specified order in the first mode and in a second specified order in the second mode The bit-swapping circuit swaps the bits of the input parallel data such that the parallel to serial conversion circuit acquires 1st to M1-th and 1st to M2-th bits of the input parallel data in the first and second modes, respectively, and arranges the acquired bits of the input parallel data in the same order.

Abstract: Evaluation of the impact of impulse noise on a communication system can be utilized to determine how the system should be configured to adapt to impulse noise events. Moreover, the system allows for information regarding impulse noise events, such as length of the event, repetition period of the event and timing of the event, to be collected and forwarded to a destination. The adaptation can be performed during one or more of Showtime and initialization, and can be initiated and determined at either one or more of a transmitter and a receiver.

Abstract: A method of reducing the glare of at least one receiver within a system, in particular a geolocation system, the system including: at least one first emitter emitting at least a first signal modulated by a first code, at least a second emitter emitting at least one second signal modulated by a second code, which is repetitive and potentially variable, and a third signal out of phase with respect to the second signal, the third signal being modulated by the second code delayed by a first delay, and the receiver, the latter being configured so as to detect signals emitted by the first and second emitters and implementing, for the tracking of the first signal, a local signal.

Abstract: The method is for managing operation of a first apparatus belonging to a first communication system and exchanging within the first communication system a multi-carrier modulated signal on several sub-carriers. The method includes detecting at the first apparatus the presence of an interfering signal emitted from a victim apparatus on a sub-carrier. The method may also include determining at the first apparatus the path loss between both apparatuses, determining from the path loss and from an allowed interference level at the victim apparatus a maximum allowed transmit power on the sub-carrier of a multi-carrier modulated signal to be transmitted from the first apparatus, and adjusting within the first apparatus the processing of the multi-carrier modulated signal to be transmitted in accordance with the maximum allowed transmit power.

Abstract: A first device receives a first signal transmitted over a transmission line from a second device. The first signal is processed and information is generated that is related to crosstalk from other transmission lines. The information is modulated onto at least one carrier of a plurality of carriers of a second signal to be transmitted from the first device to the second device.

Abstract: A transceiver circuit is disclosed. The transceiver circuit comprises a receive path to receive a differential signal and a first crosstalk filter coupled to the receive path. A common-mode path is provided for carrying a common-mode signal. An RFI interference filter is coupled between the common-mode path and the receive path. Isolation circuitry decouples the RFI interference filter from the first crosstalk filter.

Abstract: A distortion compensation device includes a storage unit storing a plurality of distortion compensation coefficients associated with power values of transmission signals, a distortion compensation processing unit acquiring a distortion compensation coefficient corresponding to a power value of a received transmission signal from among the plurality of distortion compensation coefficients and subjecting the received transmission signal to a distortion compensation process on the basis of the acquired distortion compensation coefficient, a phase calculating unit calculating a phase correction value on the basis of the distortion compensation coefficients, a phase correcting unit generating a reference signal by correcting a phase of the received transmission signal on the basis of the phase correction value, and a correction processing unit performing a correction process for the transmission signal subjected to the distortion compensation process on the basis of the reference signal and a feedback signal from

Abstract: A communication system adaptively cancels noise and/or interference from signals communicated through a communication channel, such as signals communicated by a telecommunication network. The system, based on a common mode signal of a received signal, generates an estimate of noise or interference within a differential mode signal of the received signal. The system then subtracts the estimate from the differential mode signal in an effort to remove noise from the differential mode signal thereby providing a differential mode signal that is substantially free of the estimated noise or interference.

Abstract: Communication systems are described that use geometrically shaped constellations that have increased capacity compared to conventional constellations operating within a similar SNR band. In several embodiments, the geometrically shaped is optimized based upon a capacity measure such as parallel decoding capacity or joint capacity. In many embodiments, a capacity optimized geometrically shaped constellation can be used to replace a conventional constellation as part of a firmware upgrade to transmitters and receivers within a communication system. In a number of embodiments, the geometrically shaped constellation is optimized for an Additive White Gaussian Noise channel or a fading channel. In numerous embodiments, the communication uses adaptive rate encoding and the location of points within the geometrically shaped constellation changes as the code rate changes.

Abstract: Outer-loop power control methods and apparatus are disclosed. In an exemplary embodiment, a short-term block error rate is measured for a received signal, and a coarse adjustment to a target signal-to-interference ratio (SIR) is calculated as a function of the short-term block error rate, a target block error rate, and a first loop tuning parameter. In some embodiments, a fine adjustment to the target SIR is also calculated, as a function of a smoothed block error rate, the target block error rate, and a second loop tuning parameter. The coarse adjustment provides quick responsiveness to received block errors, while the fine adjustment moderates the coarse adjustments by accounting for a longer-term view of the received block error rate. The target SIR adjustments disclosed herein may be computed in each of several iterations of an outer-loop power control loop.

Abstract: System for converting a radiofrequency signal SRX so as to recover encoded information carried by the signal SRX, includes generating elements arranged to generate a signal SLO, mixing elements (3) arranged to generate a signal SRX-LO by mixing the signal SRX with the signal SLO, an analog/digital converter arranged to convert the signal SRXLO into a digital signal SRX-LO-Num, a device generating an error correction digital signal SCor, the device being arranged so that the signal SCor reflects the phase gap between the phase of the signal SLO and a phase setpoint, the phase setpoint being the phase of an ideal signal S0, ideal for recovering the encoded information carried by the signal SRX, combining elements arranged to generate the signal S0?-Num by combining the signal SRX-LO-Num with the signal SCor. A system for converting a digital signal so as to send a radiofrequency analog signal carrying the information of the digital signal is also described.

Abstract: Embodiments of the invention relate to methods and devices for predicting a figure of merit from a distribution at least including scalably normalizing the distribution to approximate a predetermined part of the normalized distribution.

Abstract: An I/Q imbalance compensation block of a RF receiver for compensating an imbalance between an in-phase component and a quadrature component of an RF signal is disclosed. The compensation block includes a conjugation block; an adaptive finite impulse response (FIR) filter; and an adder. The filter use filter coefficients iteratively updated at least partly in response to a compensated digital signal. The filter can have a complex number for at least one, but not all of filter taps, and real numbers for other filter taps. The filter can be provided with adaptation step sizes different from filter tap to filter tap. The filter can also be provided with an adaptation step size(s) varying over time. The filter can also be provided with an adaptation step size(s) divided by the square norm of the compensated signal.

Abstract: A wireless modem and noise cancellation method for the same for noise cancellation effectively cancels a noise signal induced from a device to which the wireless modem is connected. A primary antenna receives a radio signal that includes a first noise signal coming from a device to which the wireless modem is connected; a secondary antenna receives a second noise signal from the connected device; a noise signal adjuster for adjusting the second noise signal received by the secondary antenna using a correlation parameter between noise signals received by the primary antenna and the secondary antenna; and a noise remover subtracts the noise signal adjusted by the noise signal adjuster from the radio signal received by the primary antenna.

Abstract: Disclosed is a binary phase shift key (BPSK) demodulating device using a phase shifter and a method thereof. The BPSK demodulating device includes an I signal generator to generate an in-phase (I) signal from a received BPSK signal, a Q signal generator to generate a quadrature-phase (Q) signal from the received BPSK signal, using a plurality of phase shifters, an oscillator to generate a first signal to separate a baseband signal, and a determining unit to determine a transmission phase angle based on the I signal and the Q signal.

Abstract: A narrowband interference (NBI) canceller is coupled to an A/D converter to receive an input signal and supply an NBI-canceled signal to an error correcting decoder. In the NBI canceller, a first arithmetic unit receives the input signal and a predicted-interference signal, and supplies a difference thereof as the interference-canceled signal. A slicer receives the interference-canceled signal and supplies a decision signal. A second arithmetic unit subtracts the decision signal from the input signal to generate a noise signal. A coarse frequency estimator receives the noise signal and analyzes the frequency spectrum to generate a coarse estimate of a fundamental frequency of the NBI. The coarse estimate is used by an adaptive narrowband interference predictor to generate the predicted-interference signal while adaptively tracking the narrowband interference. Use of the NBI canceller in a transceiver can eliminate link drop caused by operation of wireless devices that generate EMI in a cable.

Abstract: The present invention discloses a data re-transferring method based on bit transformation in a communication system which adopts a high order modulation and supports a re-transferring mechanism. The method includes the processes of: exchanging the location of each bit modulated to a symbol in a constellation figure used in Quadrature Amplitude Modulation (QAM) according to a selected transformation mode; mapping re-transferred data to each bit modulated to a symbol in a constellation figure of which the location has been exchanged; performing the QAM of the re-transferred data. With the method, storage amount can be decreased, balance of reliability of bits within the same data symbol after multiple re-transferring processes can be ensured, in addition, performance of the decoder and reliability of data transmission can be improved.

Abstract: A pulse signal transmitting/receiving device is provided. The device includes a signal generating module for generating a transmitting signal including an amplitude-modulated chirp signal, and a reference signal including a chirp signal having a frequency that changes similarly to that of the transmitting signal, a transmitting module for transmitting a pulse having approximately the same waveform as that of the transmitting signal, a receiving module for receiving an echo signal that is the transmitting pulse reflected from a detection target object, a compensating module for extending a dynamic range of the echo signal received by the receiving module, and a pulse compressing module for outputting a pulse-compressed echo signal, wherein the pulse compression is performed by a correlation calculation between the echo signal having the dynamic range extended by the compensating module, and the reference signal.

Abstract: Outer-loop power control methods and apparatus are disclosed. In an exemplary embodiment, a short-term block error rate is measured for a received signal, and a coarse adjustment to a target signal-to-interference ratio (SIR) is calculated as a function of the short-term block error rate, a target block error rate, and a first loop tuning parameter. In some embodiments, a fine adjustment to the target SIR is also calculated, as a function of a smoothed block error rate, the target block error rate, and a second loop tuning parameter. The coarse adjustment provides quick responsiveness to received block errors, while the fine adjustment moderates the coarse adjustments by accounting for a longer-term view of the received block error rate. The target SIR adjustments disclosed herein may be computed in each of several iterations of an outer-loop power control loop.

Abstract: An embodiment of the present invention provides an apparatus, comprising a receiver capable of selecting optimal pilot locations and providing feedback of the pilot locations to a transmitter in communication with the receiver. The optimal pilot locations may be selected by locations that avoid strong interference or platform noise at the receiver, by locations that avoid deep fading, by locations that maximize the spacing between pilot tones at the two ends of a wireless frequency band or by locations that equalize the interspacing between any two adjacent pilots.

Abstract: A unique digital compression technology for increasing the information carrying capacity of a bandwidth limited communications path highway by using a combined coding and modulation technique. The inventive technology allows multiple independent modulated data streams to simultaneously and instantaneously share the same bandwidth without cross-channel interference. A matched filter is used to substantially reduce the error rate and utilizes a unique training method based on performing a spectral response test. An algorithm calculates the effect of the unique characteristics of the communications highway on the transmitted signal and generates an ideal signal stored in the matched filter for comparison with received signals.

Abstract: The present invention relates to a precoder and a precoding method in a multi-user multi-antenna communication System. When a transmission part (100) having a plurality of antennas transmits a plurality of signals to a receiving part (200) having an antenna, the precoder and the precoding method using the same prevents System performance degradation caused by interference signals and efficiently reduces transmission power while changing the constellation rotary angle. When the power is controlled by using the precoder, the System performance is enhanced while not damaging the structural gain of the existing multi-user multi-antenna precoder.

Abstract: A demodulator for demodulating a digital broadcast signal and a demodulation method thereof. A QPSK demodulator of a digital broadcast reception system includes an in-phase/quadrature (I/Q) detector. The I/Q detector generates a baseband I signal and a baseband Q signal by multiplying a modulated QPSK signal by an I/Q carrier signal. A bandwidth adjustable first filter receives the baseband I signal and the baseband Q signal generated by the I/Q detector and rejects imaginary noise included in the received signals. A data restoration unit restores original data before the signals output from the first filter are QPSK modulated.

Abstract: Disclosed herein is an echo cancellation and echo channel estimation system that can relay transmit signals without interference with echo signals by canceling the undesired echo signals received by a relay. The echo cancellation and echo channel estimation system is designed to relay signals between a transmitter and a receiver through a relay using multiple antennas. The echo cancellation and echo channel estimation system includes a receive antenna, a preprocessing vector generation module, an echo cancellation module, and a transmit array antenna. The receive antenna receives a transmit signal from the transmitter and an echo signal via an echo channel. The preprocessing vector generation module generates a preprocessing vector and applies the preprocessing vector, the transmit signal and the echo signal, received from the receive antenna, to the echo cancellation module.

Abstract: Methods and apparatuses for encoding a plurality of bits into a plurality of pairs of simultaneous electrical pulses.

Abstract: A method, and circuitry, for choosing the correct equalization curve in adaptive equalization uses a feedback loop in which the incoming high-speed serial data are digitized and deserialized for use in the remainder of the device, and also are used by an adaptive state machine to both extract the reference levels for digitization and to control the equalization curve. Detection of the reference level and selection of the equalization curve may be performed at a different rates to avoid interfering with one another. The state machine preferably is programmable. This is useful in any device, but is particularly well-suited for a programmable device, such as a PLD or other programmable integrated circuit device, where conditions may vary according a user logic design.

Abstract: A modulated optical system with anti-clipping reduces or corrects clipping that might occur in the laser as a result of negative spikes or peaks in a multichannel RF signal. The system generally detects an envelope of the RF signal to generate an anti-clipping signal that follows at least a portion of the envelope and prevents one or more negative peaks from causing clipping by adjusting a bias current in response to the anti-clipping signal. The system may also reduce cross modulation by clamping the anti-clipping signal at an anti-clipping limit during lower power periods of the RF signal.

Abstract: A system includes a programmable transmitter device (e.g., a PLD) connected to a programmable receiver device (e.g., another PLD) via a transmission medium for transmitting a high-speed data signal from the transmitter to the receiver. During a test mode of operation a low-speed communication link between the transmitter and receiver allows those devices to work together to transmit test signals having known characteristics from the transmitter to the receiver via the transmission medium, to analyze the test signals as received by the receiver, and to adjust at least some aspect of the system (e.g., equalizer circuitry in the receiver) to at least partly compensate for losses in the test signals as received by the receiver.

Abstract: A method for inverting telecommunication channel distortion by adaptive wavelet lifting. The distortion signal is analyzed using wavelet lifting and the inverse filter is computed. Coefficients of the inverse filter are used to either compute a transmission pre-filter or to update the transmitted message.

Abstract: A differential receiver which provides for estimation and tracking of frequency offset, together with compensation for the frequency offset. Estimation and tracking of the frequency offset is undertaken in the phase domain, which reduces computational complexity and allows frequency offset estimation and tracking to be accomplished by sharing already-existing components in the receiver. Compensation for the frequency offset can be performed either in the time domain, before differential detection, or in the phase domain, after demodulation, or can be made programmably selectable, for flexibility.

Abstract: An apparatus and method for estimating a carrier-to-interference-and-noise ratio (CINR) of a received signal in an orthogonal frequency division multiplexing (OFDM) system are provided. A band-pass filter attenuates a signal region of the received signal and passes a signal in a noise region. A first power calculator calculates interference and noise power of the noise-region signal received from the band-pass filter. A second power calculator calculates total received power of the received signal. A ratio calculator calculates a CINR based on the interference and noise power, and the total received power.

Abstract: A multimode wireless communication device capable of communicating pursuant to first and second communication protocols, including a method wherein a determination is made (530) as to whether a harmonic generated during transmission in one protocol interferes with reception in another protocol, and wherein transmission is suspended while receiving only if a harmonic generated during transmission interferes with reception. In some embodiments, the transmitter is temporarily operated in compressed mode to enable the suspension.