A polar transmitter is provided. The polar transmitter includes a baseband generation unit configured to generate phase data bits and amplitude data bits of an output pulse. The polar transmitter further includes a bandwidth control unit downstream to the baseband generation unit configured to regulate the width of the output pulse. Moreover, the polar transmitter includes a pulse shaping unit downstream to the bandwidth control unit configured to generate a predefined amplitude envelope of the output pulse. In this context, the pulse shaping unit includes a delay-line with a plurality of taps, where each tap output is configured to be amplitude weighted in order to generate the amplitude envelope of the output pulse.

Embodiments of the present disclosure provide mechanisms that enable designing an FIR filter that would have a guaranteed globally optimal magnitude response in terms of the minimax optimality criterion given a desired weight on the error in the stopband versus the passband. Design of such a filter is based on a theorem (“characterization theorem”) that provides an approach for characterizing the global minimax optimality of a given FIR filter h[n], n=0, 1, . . . , N, where optimality is evaluated with respect to a magnitude response of this filter, |H(e.sup.jω)|, as compared to the desired filter response, D(ω), which is unity in the passband and zero in the stopband. The characterization theorem enables characterizing optimality for both real-valued and complex-valued filter coefficients, and does not require any symmetry in the coefficients, thus being applicable to all non-linear phase FIR filters.

Systems and methods are directed to phase modulation of polar coordinates in a transmitter of wireless signals, to achieve high transmit power levels while meeting spectral mask and EVM requirements. An input signal is mapped to a sequence of modulation frequency (e.g., O-QPSK to MSK) to generate a mapped signal. A digital frequency shaping filter is applied to the mapped signal to generate a shaped signal. An adaptive rounding algorithm is applied to the shaped signal to generate a reduced bit-width signal. A digital frequency synthesizer is applied to the reduced bit-width signal to generate an analog waveform for transmission.

The estimation and mitigation of swept-tone interferers includes receiving a composite signal comprising a signal of interest and a swept-tone interferer over an observation bandwidth or a hop bandwidth in a frequency-hopping system. The estimation of the interfering signal may be based on modeling the interferer as a magnitude periodic signal comprising non-overlapping, contiguous epochs, where each epoch may comprise a common pulse shape and a distinct phase rotation. The modeling may be based over the observation bandwidth, the hop bandwidth, or after combining the signal over all the frequency hop bandwidths. The period of the magnitude-periodic signal may be initially determined, and the common pulse shape and each of the distinct phase rotations may then be estimated. These estimates may be used to reconstruct an estimate of the swept-tone interferer, which may be subtracted from the composite signal to generate an interference-mitigated signal of interest.

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may tune an auxiliary receiver within a first radio to a transmission frequency of a co-located second radio. The auxiliary receiver may downconvert a signal from the second radio so that the UE may generate an interference estimate and perform interference cancellation. In some cases, the auxiliary receiver may also be used to perform transmission corrections for transmissions of the first radio. For example, the auxiliary receiver may be used to enable gain control or digital predistortion. The auxiliary receiver may be selectively tuned to the transmission frequency of the first radio or the second radio based on whether the auxiliary receiver is being used to perform interference cancellation or transmission correction.

A polar transmitter is provided. The polar transmitter includes a baseband generation unit configured to generate phase data bits and amplitude data bits of an output pulse. The polar transmitter further includes a bandwidth control unit downstream to the baseband generation unit configured to regulate the width of the output pulse. Moreover, the polar transmitter includes a pulse shaping unit downstream to the bandwidth control unit configured to generate a predefined amplitude envelope of the output pulse. In this context, the pulse shaping unit includes a delay-line with a plurality of taps, where each tap output is configured to be amplitude weighted in order to generate the amplitude envelope of the output pulse.

Systems and methods for ultra-wideband Crest Factor Reduction (CFR) are provided. In some embodiments, a method performed by a wireless node for performing CFR includes performing a first CFR step on a plurality of input signals at a first sampling rate with joint peak detection and band-specific noise shaping; and performing a second CFR step on the resulting plurality of input signals at a second sampling rate with joint peak detection and joint noise shaping where the second sampling rate is higher than the first sampling rate. In this way, Peak-to-Average Power Ratio (PAPR) reduction may be increased while the computational complexity is reduced.

According to an embodiment of the disclosure, a base station communicating by using a plurality of antennas includes: a memory; a transceiver including the plurality of antennas forming an array structure; and at least one processor configured to convert first in-phase quadrature (IQ) data included in a first digital signal into radio frequency (RF) signals and then apply the RF signals to the plurality of antennas, respectively, detect a back-lobe signal beam-formed by the plurality of antennas, and perform linearization on second IQ data included in a second digital signal, based on the detected back-lobe signal.

A receiving apparatus includes a first sample circuit configured to extract first binary data based on a first voltage and a clock timing of a received signal, a second sample circuit configured to extract second binary data based on an adjustable second voltage and a clock timing of the received signal, and a waveform processor configured to acquire a plurality of the second binary data from the second sample circuit using a pattern, the pattern corresponding to the first binary data extracted by the first sample circuit with consecutive sampling timings, determine an appearance frequency of the received signal based on the plurality of second binary data and the first binary data, and generate waveform information of the received signal according to the determined appearance frequency.

Systems and methods for ultra-wideband Crest Factor Reduction (CFR) are provided. In some embodiments, a method performed by a wireless node for performing CFR includes performing a first CFR step on a plurality of input signals at a first sampling rate with joint peak detection and band-specific noise shaping; and performing a second CFR step on the resulting plurality of input signals at a second sampling rate with joint peak detection and joint noise shaping where the second sampling rate is higher than the first sampling rate. In this way, Peak-to-Average Power Ratio (PAPR) reduction may be increased while the computational complexity is reduced.