An apparatus for generating a set of spectral correlation coefficients of an input signal includes: a master laser configured to generate an optical frequency comb signal; a first optical modulator configured to modulate the optical frequency comb signal with an input signal to generate a plurality of spectral copies of the input signal; a dispersive element configured to delay the plurality of spectral copies of the input signal by a wavelength-dependent time delay; a second optical modulator configured to modulate the delayed plurality of spectral copies with a conjugate of the input signal; and an optical comb filter configured to integrate the conjugate modulated plurality of spectral copies of the input signal to generate a set of cyclic autocorrelation coefficients.

Systems and methods for isolating radio frequency (RF) signals in high frequency circuit assemblies, including but not limited to 5G communication systems, are provided. The circuit assemblies include an RF suppression structure, which can be in the form of a low ohm resistor, that extends across a transmission line, and that has contacts that are electrically joined to a ground plane. Alternatively or in addition, the circuit assemblies include a low ohm resistor that extends over a transition between a signal via and an end of a transmission line, and that has contacts that are electrically joined to a ground plane. A circuit assembly as disclosed herein can further include multiple low ohm resistors spaced apart from one another by a distance that is a fraction of a wavelength of a highest frequency signal carried by the transmission line.

Systems and methods for isolating radio frequency (RF) signals in high frequency circuit assemblies, including but not limited to 5G communication systems, are provided. The circuit assemblies include an RF suppression structure, which can be in the form of a low ohm resistor, that extends across a transmission line, and that has contacts that are electrically joined to a ground plane. Alternatively or in addition, the circuit assemblies include a low ohm resistor that extends over a transition between a signal via and an end of a transmission line, and that has contacts that are electrically joined to a ground plane. A circuit assembly as disclosed herein can further include multiple low ohm resistors spaced apart from one another by a distance that is a fraction of a wavelength of a highest frequency signal carried by the transmission line.

Apparatuses, systems, and methods for a wireless device to detect intermodulation issues and configure a transmission scheme to remedy detected intermodulation issues. The wireless device may perform measurements on a downlink carrier while one uplink carrier is scheduled for the wireless device. The wireless device may also perform measurements on the downlink carrier while two uplink carriers are scheduled for the wireless device. The wireless device may provide information based on those measurements to a serving base station. The base station may determine that an intermodulation issue is occurring at the wireless device based on the information provided, and may configure the wireless device to use a single uplink carrier at a time based at least in part on the intermodulation issue.

Apparatuses, systems, and methods for a wireless device to detect intermodulation issues and configure a transmission scheme to remedy detected intermodulation issues. The wireless device may perform measurements on a downlink carrier while one uplink carrier is scheduled for the wireless device. The wireless device may also perform measurements on the downlink carrier while two uplink carriers are scheduled for the wireless device. The wireless device may provide information based on those measurements to a serving base station. The base station may determine that an intermodulation issue is occurring at the wireless device based on the information provided, and may configure the wireless device to use a single uplink carrier at a time based at least in part on the intermodulation issue.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine, based at least in part on a decomposition rule for a discrete Fourier transform (DFT) block, a plurality of decomposition groups for tones, corresponding to a plurality of antenna ports of the UE, of a transmission. The UE may map the tones to the plurality of decomposition groups for transmission processing, and transmit, using the plurality of antenna ports, the transmission based at least in part on transmission processing. Numerous other aspects are provided.

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine, based at least in part on a decomposition rule for a discrete Fourier transform (DFT) block, a plurality of decomposition groups for tones, corresponding to a plurality of antenna ports of the UE, of a transmission. The UE may map the tones to the plurality of decomposition groups for transmission processing, and transmit, using the plurality of antenna ports, the transmission based at least in part on transmission processing. Numerous other aspects are provided.

Covert acoustic communications (CAC) through solid propagation channels that connect node pairs is achieved by encoding signals using spread spectrum coding techniques that position the encoded signal at a center frequency f.sub.c within a narrow frequency bandwidth BW.sub.NB in which the amplitude of the channel response H(f) between each node pair is relatively high. The channel response H(f), bandwidth BW.sub.NB and center frequency f.sub.c, and accordingly the signal data rate will adapt for each node pair and possibly each side of the node pair. A pre-distortion filter 1/H(f) pre-distorts the encoded signal over bandwidth BW.sub.NB to compensate for material and modal dispersion and multipath between the node pair. This technique avoids the problems associated with frequency dependent attenuation of the continuous solid path and allows for simultaneous transmission and reception of signals among the multiple node pairs.

A transmitter is configured to generate a signal carrying data. A signal splitter is configured to generate multiple copies of the signal. A slip ring includes first and second portions, one configured to rotate relative to the other. The slip ring also includes a first interface associated with the first portion and configured to receive the multiple copies of the signal. The slip ring further includes a second interface associated with the second portion. In addition, the slip ring includes multiple electrical pathways electrically coupling the first and second interfaces, where at least some of the electrical pathways are configured to transport the multiple copies of the signal from the first interface to the second interface. A signal combiner is configured to receive the multiple copies of the signal from the second interface and to generate a recovered signal. A receiver is configured to recover the data from the recovered signal.

A transmitter is configured to generate a signal carrying data. A signal splitter is configured to generate multiple copies of the signal. A slip ring includes first and second portions, one configured to rotate relative to the other. The slip ring also includes a first interface associated with the first portion and configured to receive the multiple copies of the signal. The slip ring further includes a second interface associated with the second portion. In addition, the slip ring includes multiple electrical pathways electrically coupling the first and second interfaces, where at least some of the electrical pathways are configured to transport the multiple copies of the signal from the first interface to the second interface. A signal combiner is configured to receive the multiple copies of the signal from the second interface and to generate a recovered signal. A receiver is configured to recover the data from the recovered signal.