Abstract: The method includes receiving a signal in a multiple carrier mobile communication system, the signal including at least two reference symbols of different types, determining a first channel estimate at a symbol position of a first reference symbol of a first type, determining a second channel estimate at a symbol position of a second reference symbol of a second type, and determining a quantity being a function of a cross-correlation between the first and second channel estimate.

Abstract: A method includes receiving a signal comprising a symbol-carrier matrix, the symbol-carrier matrix including a predetermined pattern of reference symbols, and determining at least one channel estimate ?i,k at at least one of the reference symbol positions of the reference symbols in the symbol-carrier matrix, wherein i=0,1,2, . . . is the carrier index and k=0,1,2, . . . is the symbol index of the symbol-carrier matrix. The method further includes determining a Doppler spread {circumflex over (?)}D on the basis of the at least one channel estimate ?i,k.

Abstract: In one implementation, a transmission apparatus includes a protocol stack for a DSL transmission system, the protocol stack includes a retransmission functionality, the retransmission functionality being provided between a sublayer of a TPS-TC layer and a data link layer, the retransmission functionality having a fragment of a packet or a group of fragments of a packet as basic retransmission unit. The protocol stack may implement a service specific retransmission functionality such that for a first class of services retransmission protection is provided and for a second class of services no retransmission protection is implemented.

Abstract: Received signal measurements are calibrated in a communication device by measuring a received signal level for each of one or more subcarriers of a transmitted signal received from another communication device, converting the measured received signal level for each of the one or more subcarriers into a corresponding measured power level, estimating a terminal-to-terminal impedance between the communication devices and calculating a corrected power level for each of the one or more subcarriers as a function of the measured power level for the subcarrier, a known reference input impedance for the communication device and the estimated terminal-to-terminal impedance.

Abstract: Embodiments related to retransmission in data communication systems are described and depicted. In one embodiment, a data packet is received and separated to a plurality of data fragments. Information indicating whether a fragment of the plurality of fragments is to be protected by retransmission is provided or information indicating whether a group of fragments is to be protected by retransmission is provided. A request for retransmission from the second transceiver unit to the first transceiver unit may be generated. Based on the request, one or more identified data fragments may be retransmitted.

Abstract: A method of transmitting data includes storing a first set of transmission data and a first set of retransmission data. A first ratio of transmission data to retransmission data is determined. A plurality of transmission data units is generated with each data unit including a portion of transmission data from the first set of transmission data and a portion of retransmission data from the first set of retransmission data in accordance with the first ratio. The plurality of transmission data units is transmitted.

Abstract: Received signal measurements are calibrated in a communication device by measuring a received signal level for each of one or more subcarriers of a transmitted signal received from another communication device, converting the measured received signal level for each of the one or more subcarriers into a corresponding measured power level, estimating a terminal-to-terminal impedance between the communication devices and calculating a corrected power level for each of the one or more subcarriers as a function of the measured power level for the subcarrier, a known reference input impedance for the communication device and the estimated terminal-to-terminal impedance.

Abstract: Methods and apparatus for calibrating received signal measurements in a digital subscriber line (DSL) device are disclosed. In an exemplary method, a received signal level is measured for each of one or more subcarriers of a digital subscriber line signal and converted into a corresponding measured power level. A corrected received power level is calculated as a function of the measured power level, a reference input impedance value, a nominal loop impedance value, and a pre-determined input impedance value for the DSL device.

Abstract: The invention relates to track supports for magnetic levitation vehicles, having at least one stator support (2) comprising a first mounting surface machined according to a preselected route, and having a plurality of stator packets (7) made of ferromagnetic sheet metal layers and mounted on the stator support (2), wherein the sheet metal layers comprise an upper longitudinal side having first cutouts and intermediate first bars, and a lower longitudinal side parallel to said first side, and wherein the first cutouts form first grooves (18) designed for positively receiving attachment bodies, and the lower longitudinal sides form a functional surface (29). The free ends of the first bars form a second mounting surface (22) adjacent to the first mounting surface, and the mounting bodies comprise T-nuts (23) disposed countersunk in the first grooves (18) and having threaded bores for mounting screws (26).

Abstract: Methods and apparatus for calibrating received signal measurements in a digital subscriber line (DSL) device are disclosed. In an exemplary method, a received signal level is measured for each of one or more subcarriers of a digital subscriber line signal and converted into a corresponding measured power level. A corrected received power level is calculated as a function of the measured power level, a reference input impedance value, a nominal loop impedance value, and a pre-determined input impedance value for the DSL device.

Abstract: Embodiments related to retransmission and a retransmission request are described and depicted.

Abstract: Embodiments related to retransmission in data communication systems are described and depicted

Abstract: A method of transmitting data includes storing a first set of transmission data and a first set of retransmission data. A first ratio of transmission data to retransmission data is determined. A plurality of transmission data units is generated with each data unit including a portion of transmission data from the first set of transmission data and a portion of retransmission data from the first set of retransmission data in accordance with the first ratio. The plurality of transmission data units is transmitted.

Abstract: A digitally implemented demodulator. A frequency-modulated signal is applied to a limiting amplifier such that the signal amplitude is fixed at a constant level. The signal is undersampled and quadrature demodulated. The demodulator generates the cross-product of the baseband complex envelope to recover the original modulating signal. A digital Frequency Shift Keyed signal can be further recovered by applying the recovered signal to a data slicer to square-up the signal, and a matched filter for improved error resistance.

Abstract: The present disclosure discloses a method and apparatus for slicing data, or “squaring up” a signal such as the output of a wireless receiver demodulator for proper interface with conventional digital logic circuits. The method involves the receiving of an input signal, the generation of a reference level, the comparison of the input signal to the reference level, and the measurement and storage of the reference level. The reference level is generated by applying the input signal to a filter, which has been previously set to an initial condition. The reference level is measured at a predetermined point in a receive data frame, and is maintained at the desired level throughout the remainder of the frame. After a frame has been received, the reference level is stored if the frame data output from the data slicer contained no errors.

Abstract: A phase-locked loop controller for a frequency hopping communications system which utilizes an indirect addressing scheme to access PLL data is provided. The controller is hardware-implemented, with little or no microcontroller processing overhead required. The controller enables simple synchronization with other units in a communications infrastructure implementation. The controller provides a simple interface for implementing dynamic channel allocation methods. An override port allows external control of the PLL with which the controller is associated. Finally, the controller can control auxilliary aspects of system operation, such as powering down a transmitter while changing PLL tuning.

Abstract: The present disclosure discloses an apparatus for generating a shaped waveform derived from a binary input signal. The apparatus receives a binary input signal and a sample clock signal. The sample clock signal changes the state of an up/down counter. The binary input signal controls the counting direction of the counter. The counter addresses a lookup table containing stored values. Also disclosed is the apparatus in which the lookup table output is converted to an analog signal by a digital-to-analog converter. The lookup table can be programmed such that the circuit output is equivalent to a filtered version of the binary input signal. The apparatus may optionally be enabled or disabled, such that the apparatus output assumes a predetermined state when disabled.