Abstract: Apparatuses, systems, and methods are described for power allocation in a superposition multiple access communication system capable of using non-uniform joint constellations or super-constellations. In one method, the conditional probability of a correctly-received symbol and a normalized weighting coefficient is calculated for each receiver and then the sum of weighted efficiencies is calculated. The optimal power allocation is determined for each receiver by maximizing the sum of weighted spectral efficiencies.

Abstract: According to an embodiment of the present disclosure, a receiver of modulated signals comprises a signal mixer, a synchronization detector, and a data demodulator. The signal mixer is configured to perform baseband down-conversion of a signal according to a mixer frequency, the signal including a synchronization header and a data payload. The synchronization detector is configured to: generate a differential signal based on the signal, perform cross-correlation of the differential signal with a reference differential signal to generate a cross-correlation output, and analyze the cross-correlation output to detect an end of the synchronization header. The data demodulator is configured to demodulate the data payload in response to detection of the end of the synchronization header.

Abstract: A receiver of a modulated signal includes a synchronization detector configured to receive a signal indicative of the modulated signal and to detect an end of the synchronization header in the signal. The synchronization detector is configured to generate a differential signal based on the signal, perform cross-correlation of the differential signal with a reference differential signal to generate a cross-correlation output, compare a first sample of the cross-correlation output at a sample index associated with a hypothesized start frame delimiter (SFD) peak index with a second sample of the cross-correlation output at a sample index associated with a hypothesized preamble peak index, and detect an end of the synchronization header in response to a comparison result in which a magnitude of the first sample of the cross-correlation output is greater than a magnitude of the second sample of the cross-correlation output.

Abstract: According to an embodiment of the present disclosure, a receiver of modulated signals comprises a signal sampling unit configured to sample a signal, a zero-crossing demodulator, and a timing offset tracking unit. The zero-crossing demodulator includes: a zero-crossing counter configured to determine a number of zero crossings for each pulse of the signal, and a symbol selector configured to decode a sequence of pulses as a symbol based on the number of zero crossings in the sequence of pulses. The timing offset tracking unit is configured to: calculate a metric based on an accumulation of the number of zero crossings and corresponding pulse values of the decoded symbol, compare the metric to a predetermined threshold value, and compensate a timing offset of the signal by causing the signal sampling unit to sample the signal at an earlier interval or a later interval in response to the comparison.

Abstract: A method and apparatus are provided. The method includes receiving a reference signal from a transceiver, estimating a time offset (TO) of the reference signal in the frequency domain based on an accumulation of subcarriers before cross-correlation, providing a TO compensated signal of the reference signal based on the estimated TO in the frequency domain, transforming the TO compensated signal into the time domain, and estimating a frequency offset (FO) based on the time domain TO compensated signal.

Abstract: According to an embodiment of the present disclosure, a receiver of modulated signals comprises a signal mixer, a synchronization detector, and a data demodulator. The signal mixer is configured to perform baseband down-conversion of a signal according to a mixer frequency, the signal including a synchronization header and a data payload. The synchronization detector is configured to: generate a differential signal based on the signal, perform cross-correlation of the differential signal with a reference differential signal to generate a cross-correlation output, and analyze the cross-correlation output to detect an end of the synchronization header. The data demodulator is configured to demodulate the data payload in response to detection of the end of the synchronization header.

Abstract: According to an embodiment of the present disclosure, a receiver of modulated signals comprises a signal sampling unit configured to sample a signal, a zero-crossing demodulator, and a timing offset tracking unit. The zero-crossing demodulator includes: a zero-crossing counter configured to determine a number of zero crossings for each pulse of the signal, and a symbol selector configured to decode a sequence of pulses as a symbol based on the number of zero crossings in the sequence of pulses. The timing offset tracking unit is configured to: calculate a metric based on an accumulation of the number of zero crossings and corresponding pulse values of the decoded symbol, compare the metric to a predetermined threshold value, and compensate a timing offset of the signal by causing the signal sampling unit to sample the signal at an earlier interval or a later interval in response to the comparison.

Abstract: A system and method for removing bias from a frequency estimate. A simulation is used to predict, for various values of the signal to noise ratio, a bias in a raw frequency estimate produced by a frequency estimation algorithm. A straight line is fit to simulated frequency offset estimates as a function of true frequency offset, and the reciprocal of the slope of the line is stored, as a multiplicative bias removal term, in a lookup table, for the simulated signal to noise ratio. In operation, the raw frequency estimate is multiplied by a multiplicative bias removal term, obtained from the lookup table, to form a corrected frequency offset estimate.

Abstract: A method and apparatus are provided. The method includes receiving a signal from a transceiver, demapping a bit pattern encoded within the signal, detecting a preamble based on the demapped bit pattern, and synchronizing the transceiver to a receiver using the preamble, wherein demapping the bit pattern is based on weighting coefficients.

Abstract: An apparatus and a method. The apparatus includes a plurality of correlation processors configured to each receive a group of samples and generate correlations of each group of samples; a plurality of multipliers each configured to multiply the correlations of one of the plurality of correlation processors by a weight, wherein the weight of at least one of the plurality of multipliers is different from the weight of at least another one of the plurality of multipliers; a summation processor configured to sum the weight multiplied correlations of the plurality of multipliers for time n, where n is an integer; and a coarse timing and coarse frequency processor configured to generate a coarse timing and a coarse frequency based on the sum.

Abstract: Methods and apparatuses are provided in which a signal is received at a receiver. A processor of the receiver computes frequency offset (FO) inter-carrier interference (ICI) compensation, based on a real matrix part of an approximate ICI matrix and an FO estimated from the received signal. The processor applies the FO ICI compensation to the received signal in a frequency domain to produce an ICI compensated output. The processor applies a phase rotation to the ICI compensated output.

Abstract: Systems and methods are provided for enhancing signal quality at receivers in a wireless network. In one embodiment, an antenna is selected from a subset of antennas based on a signal quality parameter such as received signal power or signal-to-noise ratio (SNR). In another embodiment, multiple antennas are applied to independent signal processing paths for the respective antennas where output from the paths is then combined to enhance overall signal quality at the receiver.

Abstract: A system to recognize user activity includes a filter to form a gravity measurement from a three-dimensional (3D) accelerometer measurement of a user activity; a body component extractor to form a body measurement of the user activity by removing the gravity measurement from the 3D accelerometer measurement; a rotation matrix calculator to form a rotation matrix that is used to rotate the extracted gravity to align with a predetermined direction, and to rotate the 3D accelerometer measurements and the body measurement to be the input to features determiner module; and a features determiner to determine values of a predetermined number of features of the user activity based on the rotated 3D accelerometer measurement and the rotated body measurement in which the predetermined number of features are invariant under arbitrary rotation of the accelerometer measurement around the predetermined direction.

Abstract: A system, method and device for wireless communication is provided. The method includes receiving, by a receiver, data from a transmitter, storing the data in the receiver, and determining, by the receiver, a probability of a bit stored in the data and a probability of a symbol based on the probability of the bit, wherein determining the probability of the bit includes moving a decision boundary associated with a constellation diagram.

Abstract: A system, method and device for wireless communication is provided. The method includes receiving, by a receiver, data from a transmitter, storing the data in the receiver, and determining, by the receiver, a probability of a bit stored in the data and a probability of a symbol based on the probability of the bit, wherein determining the probability of the bit includes moving a decision boundary associated with a constellation diagram.

Abstract: A method and an apparatus are provided for determining whether an enhanced physical downlink control channel (ePDCCH) transmission exists for a user equipment (UE) in a subframe. The UE receives a transmission on physical downlink control channel (PDCCH) resources of the subframe. Downlink control information (DCI) is extracted from the PDCCH resources. The DCI includes at least one bit indicating whether the ePDCCH transmission exists for the UE in the subframe. The UE determines whether the ePDCCH transmission exists using the at least one bit. Additional symbols of the subframe are buffered and decoded when the ePDCCH transmission exists.

Abstract: Systems and methodologies are described that facilitate monitoring RF channels in a wireless communication environment to determine whether one or more channels comprise a forward-link-only (FLO) signal. A receiver can receive a first RF channel with a FLO signal and can monitor other RF channels for FLO signals. Upon a determination that a monitored RF channel comprises a FLO signal, the receiver can switch between the first RF channel and the monitored RF channel, employing information on current MLC decoding status, to facilitate providing seamless reception of the FLO signal, which can be superframe synchronized between RF channels. FLO signal detection can be performed using one or more of a wide-area identification channel energy detection protocol and a wide-area overhead information symbol decoding error detection protocol.

Abstract: Apparatuses, systems, and methods are described for power allocation in a superposition multiple access communication system capable of using non-uniform joint constellations or super-constellations. In one method, the conditional probability of a correctly-received symbol and a normalized weighting coefficient is calculated for each receiver and then the sum of weighted efficiencies is calculated. The optimal power allocation is determined for each receiver by maximizing the sum of weighted spectral efficiencies.

Abstract: Apparatuses, systems, and methods are described concerning a new type of superposition multiplexing transmission constellation (super-constellation): the Gray-mapped Non-uniform-capable Constellation (GNC). Apparatuses, systems, and methods for generating GNC super-constellations are described, as well as apparatuses, systems, and methods for receiving, demapping, and decoding transmissions using GNC super-constellations. Apparatuses, systems, and methods for selecting a type of superposition multiplexing transmission constellation based on various conditions are also described.

Abstract: A method and an apparatus are provided for determining whether an enhanced physical downlink control channel (ePDCCH) transmission exists for a user equipment (UE) in a subframe. The UE receives a transmission on physical downlink control channel (PDCCH) resources of the subframe. Downlink control information (DCI) is extracted from the PDCCH resources. The DCI includes at least one bit indicating whether the ePDCCH transmission exists for the UE in the subframe. The UE determines whether the ePDCCH transmission exists using the at least one bit. Additional symbols of the subframe are buffered and decoded when the ePDCCH transmission exists.