Abstract: Aspects of the disclosure related to devices, wireless communication apparatuses, methods, and other aspects of passive multiple input multiple output. In some aspects, an apparatus is provided that includes a first radio frequency (RF) transmission line having a first terminated with a quarter wavelength grounded transmission line, and a first array of antennas including a plurality of antenna elements. The apparatus also includes a switch array including a corresponding switch for each antenna element of the plurality of antenna elements of the first array of antennas, to selectively connect each antenna element to the first RF transmission line, and path lengths selectable by the switches at half wavelength distances for passive transmission. The apparatus also includes or more lens elements configured to modify wireless inputs signals to the first array of antennas and to modify wireless output signals from the first array of antennas.

Abstract: Designs and control techniques for passive Multiple-Input Multiple-Output (pMIMO) surfaces are provided. An example array of reconfigurable reflective elements includes a plurality of unit cells each comprising a cross-slot radiating element, a first varactor diode disposed across a first end of the cross-slot radiating element and configured to control polarization in a first plane, and a second varactor diode disposed across a second end of the cross-slot radiating element and configured to control polarization in a second plane, and a controller coupled to the first varactor diode and the second varactor diode and configured to provide control signals to the first varactor diode and the second varactor diode to vary a direction of a reflected signal.

Abstract: A method of using an antenna system, comprising a transducer that is configured to transduce between wireless signals and wired signals and that is disposed between a ground conductor and a frequency selective surface, includes: providing constructive interference between a first signal of a first frequency and a reflected first signal comprising a reflection of a portion of the first signal by the frequency selective surface and the ground conductor; and providing constructive interference between a second signal of a second frequency, different from the first frequency, and a reflected second signal comprising a reflection of a portion of the second signal by the frequency selective surface and the ground conductor.

Abstract: During an uplink TDD slot, an UL UE transmits an UL signal that occupies a slot frequency range. Similarly, during a DL TDD slot, a DL UE receives a DL signal that occupies the slot frequency range. But during an SBFD slot, a UL UE transmits a UL signal that occupies only a first sub-band of the slot frequency range. Similarly, a DL UE receives a DL signal during an SBFD slot that occupies only a second sub-band of the slot frequency range. The second sub-band is distinct from the first sub-band. The DL UE may thus mitigate UE-to-UE interference during an SBFD slot by filtering the DL signal to substantially block the second sub-band from being received at the DL UE.

Abstract: Aspects relate to an array antenna and communication using the array antenna. In some examples, the array antenna includes a first array of antenna elements arranged according to a first circle and a second array of antenna elements arranged according to a second circle, where the first circle and the second circle are concentric circles. In some examples, the first array of antenna elements is arranged with an angular offset with respect to the second array of antenna elements. For example, a first radius associated with a first antenna element of the first array of antenna elements may be offset at an angle with respect to a second radius of a second antenna element of the second array of antenna elements.

Abstract: Methods, systems, and devices for wireless communications are described for self-interference or cross-link interference measurements at a user equipment (UE). A UE may receive configuration information from a base station that indicates one or more slot format index (SFI) values that are compatible for cross-link interference or self-interference measurements. Based on the configured SFI(s), the UE may measure interference in multiple symbols, which may be used to estimate an amount of cross-link interference or self-interference, and the UE may transmit a measurement report to the base station. The base station, based on the measurement report, may identify one or more compatible SFIs, beam pairs, or combinations thereof, for subsequent communications with one or more UEs. The interference measurements may identify cross-link interference at the UE that results from transmissions of a different UE, or may identify self-interference of concurrent communications of multiple channels at a same UE.

Abstract: A wireless communication device includes: a first antenna configured to provide a first gain pattern at a millimeter-wave radio frequency and having a first boresight direction; a second antenna configured to provide a second gain pattern at the millimeter-wave radio frequency and having a second boresight direction that is different from the first boresight direction; and an electrically-conductive device; where the first antenna, in combination with the electrically-conductive device, is configured to provide a third gain pattern that has a first gain differential relative to the second gain pattern that is greater than a second gain differential between the first gain pattern and the second gain pattern over a range of angles relative to the wireless communication device.

Abstract: A wireless communication device includes: a first antenna configured to provide a first gain pattern at a millimeter-wave radio frequency and having a first boresight direction; a second antenna configured to provide a second gain pattern at the millimeter-wave radio frequency and having a second boresight direction that is different from the first boresight direction; and an electrically-conductive device; where the first antenna, in combination with the electrically-conductive device, is configured to provide a third gain pattern that has a first gain differential relative to the second gain pattern that is greater than a second gain differential between the first gain pattern and the second gain pattern over a range of angles relative to the wireless communication device.

Abstract: A wireless communication device includes: a first antenna configured to provide a first gain pattern at a millimeter-wave radio frequency and having a first boresight direction; a second antenna configured to provide a second gain pattern at the millimeter-wave radio frequency and having a second boresight direction that is different from the first boresight direction; and an electrically-conductive device; where the first antenna, in combination with the electrically-conductive device, is configured to provide a third gain pattern that has a first gain differential relative to the second gain pattern that is greater than a second gain differential between the first gain pattern and the second gain pattern over a range of angles relative to the wireless communication device.

Abstract: A base station is disclosed that includes two separated antenna arrays. In a TDD mode of operation, both arrays are used for either transmit or receive. In a sub-band full-duplex mode of operation, one array is used to transmit downlink symbols while the remaining array is used to receive uplink symbols.

Abstract: Aspects of the disclosure relate to an apparatus (e.g., a user equipment (UE)) configured to operate in a full-duplex mode. The apparatus may include at least one transmit chain configured to operate within a first frequency band and at least one receive chain configured to operate within a second frequency band. The apparatus may receive coordination information that is configured to mitigate the self-interference between the at least one transmit chain of the apparatus and the at least one receive chain of the apparatus. In some examples, the received coordination information includes at least one of subcarrier spacing coordination information, beam coordination information, or slot format index coordination information. In some examples, the apparatus may transmit a first signal while receiving a second signal based on at least the subcarrier spacing coordination information, the beam coordination information, or the slot format index coordination information to mitigate self-interference.

Abstract: A first wireless communication device, such as a base station, may include separate transmit and receive antenna arrays. The separation between the transmit and receive antenna arrays may cause a direction of a transmit beam formed at the transmit antenna array to be different from a direction of a receive beam formed at the receive antenna array. The transmit and receive beams may be formed for communication with a second wireless communication device, such as a user equipment (UE). The described aspects enable the first wireless communication device to monitor a difference between a first direction of the transmit beam and a second direction of the receive beam. The first wireless communication device may transmit an indication of a beam correspondence failure to the second wireless communication device when the difference between the first and second directions is greater than or equal to a beam correspondence threshold.

Abstract: Generally, the described techniques provide for efficiently transmitting uplink signals to a base station using shared antennas associated with different power classes. A first device may be in communications with a base station using local antennas and may identify a second device having auxiliary antennas available for transmitting uplink signals to the base station. The local and auxiliary antennas may be associated with different power classes, and the first device may transmit a message to a base station indicating that the first device is capable of transmitting using antennas associated with different power classes. The first device may then receive configurations from a base station of different transmit powers to transmit on the antennas associated with the different power classes, and the first device may transmit uplink signals to the base station in accordance with the different transmit power configurations.

Abstract: Disclosed are techniques for determining a line-of-sight (LOS) path between a transmitter and a wireless device. In an aspect, a wireless device receives a first reference signal on a first frequency band at a first time, receives a second reference signal on a second frequency band at a second time, compares the first time to the second time, and determines, at least based on the comparison of the first time to the second time, which of the first reference signal and/or the second reference signal followed the LOS path between the transmitter and the wireless device.

Abstract: Generally, the described techniques provide for efficiently transmitting uplink signals to a base station using shared antennas associated with different power classes. A first device may be in communications with a base station using local antennas and may identify a second device having auxiliary antennas available for transmitting uplink signals to the base station. The local and auxiliary antennas may be associated with different power classes, and the first device may transmit a message to a base station indicating that the first device is capable of transmitting using antennas associated with different power classes. The first device may then receive configurations from a base station of different transmit powers to transmit on the antennas associated with the different power classes, and the first device may transmit uplink signals to the base station in accordance with the different transmit power configurations.

Abstract: Disclosed are techniques for determining a line-of-sight (LOS) path between a transmitter and a wireless device in a wireless communications network. In an aspect, a wireless device receives, from the transmitter, a first reference signal transmitted on a first antenna port and a second reference signal transmitted on a second antenna port, the first reference signal having a first polarization and the second reference signal having a second polarization with known difference (e.g., perpendicular) to the first polarization, compares multi-path channels estimated from reception of the first reference signal and the second reference signal to multi-path channels expected from the first reference signal and the second reference signal when transmitted along the LOS path between the transmitter and the wireless device, and determines which path (if any) of the multi-path channels corresponds to the LOS path between the transmitter and the wireless device.

Abstract: Methods, systems, and devices for wireless communications are described for self-interference or cross-link interference measurements at a user equipment (UE). A UE may receive configuration information from a base station that indicates one or more slot format index (SFI) values that are compatible for cross-link interference or self-interference measurements. Based on the configured SFI(s), the UE may measure interference in multiple symbols, which may be used to estimate an amount of cross-link interference or self-interference, and the UE may transmit a measurement report to the base station. The base station, based on the measurement report, may identify one or more compatible SFIs, beam pairs, or combinations thereof, for subsequent communications with one or more UEs. The interference measurements may identify cross-link interference at the UE that results from transmissions of a different UE, or may identify self-interference of concurrent communications of multiple channels at a same UE.

Abstract: A non-geosynchronous satellite system, where each satellite has an antenna (perhaps a multi-element antenna) to form a beam pattern comprising a set of beams in the footprint of the satellite, where in one implementation each beam is substantially elliptical in shape having a minor axis and a major axis, where the minor axes are substantially collinear and the major axes are substantially oriented east to west. For a satellite, power is reduced or turned off for a subset of the set of beams, wherein each beam in the subset is reduced at or below a corresponding power level such that when a beam is powered above its corresponding power level an equivalent power flux-density (EPFD) exceeds a limit at some point on the Earth's surface.

Abstract: Aspects of the disclosure relate to an apparatus (e.g., a user equipment (UE)) configured to operate in a full-duplex mode. The apparatus may include at least one transmit chain configured to operate within a first frequency band and at least one receive chain configured to operate within a second frequency band. The apparatus may receive coordination information that is configured to mitigate the self-interference between the at least one transmit chain of the apparatus and the at least one receive chain of the apparatus. In some examples, the received coordination information includes at least one of subcarrier spacing coordination information, beam coordination information, or slot format index coordination information. In some examples, the apparatus may transmit a first signal while receiving a second signal based on at least the subcarrier spacing coordination information, the beam coordination information, or the slot format index coordination information to mitigate self-interference.

Abstract: Generally, the described techniques provide for efficiently transmitting uplink signals to a base station using shared antennas associated with different power classes. A first device may be in communications with a base station using local antennas and may identify a second device having auxiliary antennas available for transmitting uplink signals to the base station. The local and auxiliary antennas may be associated with different power classes, and the first device may transmit a message to a base station indicating that the first device is capable of transmitting using antennas associated with different power classes. The first device may then receive configurations from a base station of different transmit powers to transmit on the antennas associated with the different power classes, and the first device may transmit uplink signals to the base station in accordance with the different transmit power configurations.