In one embodiment, an apparatus includes: a radio frequency (RF) front end circuit to receive and downconvert a RF signal to a second frequency signal, the RF signal comprising an orthogonal frequency division multiplexing (OFDM) transmission; a digitizer coupled to the RF front end circuit to digitize the second frequency signal to a digital signal; and a baseband processor coupled to the digitizer to process the digital signal. The baseband circuit comprises a first circuit having a first plurality of correlators having an irregular comb structure, each of the first plurality of correlators associated with a carrier frequency offset and to calculate a first correlation on a first portion of a preamble of the OFDM transmission.

In one embodiment, an apparatus includes: a baseband processor having a preamble generation circuit to generate a preamble for an orthogonal frequency division multiplexing (OFDM) transmission, the preamble generation circuit to generate the preamble having a first portion comprising a first plurality of symbols, each of the first plurality of symbols having a plurality of carriers, where a subset of the plurality of carriers have non-zero values, the preamble generation circuit to generate the non-zero values using a sequence of complex values selected to optimize a peak-to-average power ratio (PAPR); a digital-to-analog converter (DAC) coupled to the baseband processor to convert the first plurality of symbols to analog signals; a mixer coupled to the DAC to upconvert the analog signals to radio frequency (RF) signals; and a power amplifier coupled to the mixer to amplify the RF signals.

A method for a wireless transmitter is disclosed. The method comprises transmitting a wake-up signal over a frequency range during a time interval by transmitting a first signal part over a first frequency interval within the frequency range during the time interval and transmitting a second signal part over a second frequency interval within the frequency range during the time interval. The first and second frequency intervals are non-overlapping. The first signal part has a first auto-correlation value, and the second signal part is specifically constructed to provide a second autocorrelation value of the signal comprising the first and second signal parts which is lower than the first auto-correlation value. The invention to solve the problem of false detection of an MC-OOK modulated wake-up signal in an IEEE 802.11 system using OFDM.

Embodiments of the present application provide a random access sequence generation method, and an apparatus. The method includes: generating, by a base station, notification signaling, where the notification signaling includes indication information, the indication information is used to instruct user equipment UE to select a shift sequence number from a range of 0 to (n.sub.shift.sup.RAn.sub.group.sup.RA+n.sub.shift.sup.RA+n.sub.shift.sup.RA+.sub.shift.sup.RA−1), the shift sequence number is an integer, n.sub.shift.sup.RA is a quantity of UE candidate sequence shifts in a group, n.sub.group.sup.RA is a quantity of groups, n.sub.shift.sup.RA is a quantity of UE candidate sequence shifts in the last length that is insufficient for a group, n.sub.shift.sup.RA is a quantity of UE candidate sequence shifts in first remaining sequence shifts, and .sub.shift.sup.RA is a quantity of UE candidate sequence shifts in second remaining sequence shifts; and sending, by the base station, the notification signaling to the UE, so that the UE generates a random access sequence according to the indication information.

Presented in the present specification is a method for a receiving terminal supporting a sidelink. The receiving terminal according to the present specification acquires a synchronization for setting a symbol boundary, applies the same symbol boundary for a plurality of receiving signals, and can set a receiving window on the basis of the symbol boundary. The receiving terminal can acquire a propagation delay applied to a plurality of wireless signals through a first wireless signal among the plurality of wireless signals, and can adjust a starting time of the receiving window for decoding a second wireless signal through the propagation delay or can feed back information related to a transmission timing to a transmission device for transmitting the second wireless signal. Therefore, an efficient decoding technique for a second wireless signal having a characteristic newer than that of a conventional technique is presented.

A communication system is configured to generate a perturbed signal by perturbing an amplitude of a spectrum of an original signal in one or more spectral regions, and to propagate the perturbed signal through components of the communication system. The communication system is further configured to obtain a measurement of the perturbed signal in a first spectral region of the one or more spectral regions following the propagation of the perturbed signal, and to calculate an estimate of an impairment associated with the communication system based on the measurement.

The present disclosure provides techniques for bandwidth constrained communication systems with frequency domain information processing. A bandwidth constrained equalized transport (BCET) communication system can include a transmitter, a communication channel, and a receiver. The transmitter can include a pulse-shaping filter that intentionally introduces memory into a signal in the form of inter-symbol interference, an error control code (ECC) encoder, a multidimensional fast Fourier transform (FFT) processing block and a multidimensional inverse FFT processing block that process the signal in the frequency domain, and a first interleaver. The receiver can include an information-retrieving equalizer, a deinterleaver with an ECC decoder, and a second interleaver joined in an iterative ECC decoding loop. The communication system can be bandwidth constrained, and the signal can comprise an information rate that is higher than that of a communication system without intentional introduction of the memory at the transmitter.

This application discloses a reference signal transmission method and apparatus. The method includes: generating one or more OFDM symbols, where at least one OFDM symbol includes a PTRS resource block, the PTRS resource block includes at least two of three sequences: a PTRS sequence of Y elements, X elements after the PTRS sequence, and Z elements before the PTRS sequence, and the PTRS resource block occupies a plurality of consecutive resource elements REs, where X, Y, and Z are all integers; and sending the one or more OFDM symbols. According to the foregoing method and apparatus, inter-carrier interference is reduced, thereby improving spectral efficiency.

A synchronisation symbol detector that comprises two correlation modules and a comparison module. The first correlation module performs one or more correlations between the input signal and a down-converted version of the input signal and generates a first correlation metric from the one or more first correlations. The second correlation module performs one or more second correlations between the input signal and an up-converted version of the input signal and generates a second correlation metric from the one or more second correlations. The comparison module is configured to compare the first correlation metric and the second correlation metric and determine whether the input signal comprises a synchronisation symbol based on the comparison.

According to an embodiment of the present invention, a method is disclosed for transmitting a signal on the basis of a competition-based non-orthogonal multiple access scheme, by means of a terminal in a wireless communication system. At this time, the method for transmitting a signal comprises: a step of transmitting a first codeword on the basis of the competition-based NoMA scheme; a step of receiving a negative response to the first codeword transmission from a base station; a step of selecting a second codeword, taking into account a magnitude vector and a correlation of the first codeword; and a step of transmitting the selected second codeword on the basis of the competition-based NoMA scheme.