Abstract: Methods, systems, and devices for wireless communications are described. In some systems implementing beamforming, a neighboring base station may cause interference to a user equipment (UE) served by a different base station. To mitigate unexpected interference, an interference coordination region including time and frequency resources may be configured between the base stations. The interference coordination region may be configured based on long-term information for the base stations and may include one or both of a set of beam-avoidance sub-regions or a set of beam-preference sub-regions for a base station, where each sub-region is associated with a beam index. A base station may schedule a communication beam in the interference coordination region based on a beam-avoidance region (e.g., refraining from using a particular communication beam) or a beam-preference region (e.g., prioritizing a particular communication beam).

Abstract: Methods, systems, and devices for wireless communications are described. A wireless device, such as a base station or a user equipment, may identify an energy detection threshold for a sensing beam associated with a channel access procedure, such as a listen-before-talk (LBT) procedure. The wireless device may also identify a set of transmit power parameters for one or more transmit beams. The wireless device may determine a degree of overlap between a beam shape of one or more transmit beams and a beam shape (e.g., a coverage area) of the sensing beam. The wireless device may adjust the set of transmit power parameters, the energy detection threshold, or a combination thereof based on the degree of overlap. The wireless device may perform the channel access procedure based on the determining, the adjusting, or both.

Abstract: Methods, systems, and devices for wireless communications are described. A wireless device, such as a base station or a user equipment, may identify an energy detection threshold for a sensing beam associated with a channel access procedure, such as a listen-before-talk (LBT) procedure. The wireless device may also identify a set of transmit power parameters for one or more transmit beams. The wireless device may determine a degree of overlap between a coverage area of one or more transmit beams and a coverage area of the sensing beam. The wireless device may adjust the set of transmit power parameters, the energy detection threshold, or a combination thereof based on the degree of overlap. The wireless device may perform the channel access procedure based on the determining, the adjusting, or both.

Abstract: Methods, systems, and devices for wireless communications are described. In some systems, transmissions from a neighboring base station may interfere with downlink transmissions from a serving base station to a target user equipment (UE). To coordinate interference between the base stations (e.g., mitigate interference, stabilize interference, etc.), the serving base station may generate an interference coordination message and may transmit the message over-the-air (OTA) to one or more neighboring base stations. The message may include parameters indicating a coordination scheme for the neighboring base station(s) to use for modifying one or more scheduling decisions. The coordination scheme may be configured or dynamically selected and may include interfering beam fixation, interfering beam suppression, or interfering beam avoidance.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive an indication of one or more waveforms supported by a base station, wherein the one or more waveforms include at least one of an orthogonal frequency division multiplexing (OFDM) waveform, a single carrier frequency domain (SC-FD) waveform, or a single carrier time domain (SC-TD) waveform. The UE may determine whether the UE is capable of communicating with the base station based at least in part on the indication. The UE may selectively communicate with the base station using at least one waveform of the one or more waveforms based at least in part on the determination. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) in communication with a serving base station may identify that the UE is a potential victim of interference from a neighboring base station. The UE may transmit an interference coordination message to the neighboring base station. The interference coordination message may request modification of one or more transmission parameters at the neighboring base station. The neighboring base station may modify its transmission parameters to decrease interference with the UE, and the UE may communicate with the serving base station after transmitting the interference coordination message.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a control channel that uses an orthogonal frequency division multiplexing (OFDM) waveform. The UE may transmit or receiving a data channel, associated with the control channel, that uses a single-carrier (SC) waveform. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described. A wireless device may select a transmission beam sequence for a wireless device during a plurality of transmission slots. The transmission beam sequence may indicate a transmission beam that the wireless device will use for its transmissions during a corresponding transmission slot. The wireless device may transmit a broadcast control signal including an indication of the transmission beam sequence. The wireless device may perform wireless transmissions over the plurality of transmission slots according to the transmission beam sequence. Other wireless devices may use the transmission beam sequence to schedule their own transmissions during the plurality of transmission slots.

Abstract: Methods, systems, and devices for time domain single carrier (SC) waveform communications are described. A user equipment (UE) may generate an SC waveform by resampling (e.g., up-sampling) mapped information bits prior to insertion of a cyclic prefix (CP) or guard interval (GI). Performing resampling prior to CP/GI insertion allows for resource allocation flexibility and a base station may allocate resources for the SC waveform in accordance with this flexibility. For example, a base station may not be limited or restricted to a certain number of resources for SC waveform communications and may therefore determine a resource allocation for the UE based on the capability of the UE to perform resampling prior to CP/GI insertion. The resampling may be performed according to a set of parameters including a resampling ratio, which may be indicated to the UE via control signaling (e.g., from the base station).

Abstract: Methods, systems, and devices for wireless communications are described that provide staggered synchronization signal blocks (SSBs) in frequency sub-bands for beamformed wireless communications. Transmissions of SSBs and control channel transmissions (e.g., remaining minimum system information (RMSI) physical downlink control channel (PDCCH) transmissions) may use multiple transmission beams in a beam sweeping procedure. The SSB transmissions may be transmitted using transmission beams that span one frequency sub-band of a number of available frequency sub-bands, and the control channel transmissions may use transmission beams that span two or more of the frequency sub-bands. The SSB beam sweeping procedure may be performed separately during staggered, non-overlapping time periods for each frequency sub-band of the number of frequency sub-bands. Each of the of SSBs may indicate a reference timing of the base station used to identify a set of resources (e.g.

Abstract: Aspects directed towards communications for random access procedures are disclosed. In one example, a first beam and a second beam may be available for communications between a scheduled entity and a scheduling entity. The scheduling entity may send, and the scheduled entity may receive, a message 1 transmission for a random access procedure on the first beam. The scheduled entity may open a random access response (RAR) window to monitor for a message 2 transmission according to a predetermined sequence designating whether to monitor the first beam, the second beam, or some combination thereof. The scheduling entity may send, and the scheduled entity may receive, the message 2 transmission on the first beam or the second beam as designated by the predetermined sequence. Other aspects, embodiments, and features are also included.

Abstract: For unlicensed high-frequency bands such as mmW bands as used in 5G NR communications, either by regulation or for coexistence with licensed frequency bands, there may be a need for a contention-based access procedure such as the LBT procedure. A challenge is to find a suitable sensing beam to functions as a proxy for a set of transmission beams. In an aspect of the disclosure, a method and an apparatus are provided. The apparatus is configured to determine a set of transmission beams for a transmission opportunity, determine a sensing beam for the set of transmission beams based on a set of beam sensing criteria; and initiate an LBT procedure by sensing an energy on the determined sensing beam. The apparatus may then use the LBT procedure to obtain the access to and transmit data on the determined set of transmission beams.

Abstract: Methods, systems, and devices for wireless communications are described. A wireless device (e.g., a user equipment and/or base station) may select a beam configuration for a wireless transmission over a channel of a radio frequency spectrum band. The wireless device may perform a listen-before-talk (LBT) procedure on the channel using a LBT detection threshold, wherein the LBT detection threshold is based at least in part on the selected beam configuration. The wireless device may perform the wireless transmission over the channel using the selected beam configuration based at least in part on a success of the LBT procedure.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may select a random access channel (RACH) signature from among one or more RACH signatures associated with a synchronization signal block (SSB). The UE may transmit, to a base station (BS), a RACH communication using the selected RACH signature. Numerous other aspects are provided.

Abstract: Methods, systems, and devices for wireless communications are described that provide staggered synchronization signal blocks (SSBs) in frequency sub-bands for beamformed wireless communications. Transmissions of SSBs and control channel transmissions (e.g., remaining minimum system information (RMSI) physical downlink control channel (PDCCH) transmissions) may use multiple transmission beams in a beam sweeping procedure. The SSB transmissions may be transmitted using transmission beams that span one frequency sub-band of a number of available frequency sub-bands, and the control channel transmissions may use transmission beams that span two or more of the frequency sub-bands. The SSB beam sweeping procedure may be performed separately during staggered, non-overlapping time periods for each frequency sub-band of the number of frequency sub-bands. Each of the of SSBs may indicate a reference timing of the base station used to identify a set of resources (e.g.

Abstract: Methods, systems, and devices for wireless communication are described. Generally, the described techniques provide for efficiently identifying a receive beam for performing a listen before talk (LBT) procedure in an attempt to gain access to a transmission opportunity (TxOP) in a shared radio frequency spectrum. In particular, a wireless device may select a receive beam that corresponds to one or more transmit beams to be used in a TxOP to perform an LBT procedure in an attempt to gain access to the TxOP. In one example, the wireless device may select a receive beam for performing an LBT procedure based on the energy of each of the transmit beams to be used in a TxOP. In another example, the wireless device may select a receive beam for performing an LBT procedure if the receive beam is quasi co-located with each of the transmit beams to be used in a TxOP.

Abstract: Methods, systems, and devices for wireless communications are described. In some systems, wireless devices operating in an unlicensed radio frequency spectrum band may perform directional listen-before-talk (LBT) procedures to gain access to a channel. In a beam-shrinking scheme for directional LBT, a wireless device may start an LBT procedure using a first beam (e.g., a wide beam). If the clear channel assessment (CCA) fails for the first beam (e.g., due to directional interference), the device may switch the LBT procedure to a second beam (e.g., a narrower beam). Depending on the direction of the interference source, the second beam may result in a successful LBT procedure. In a beam sweeping scheme for directional LBT, a wireless device may perform concurrent LBT over multiple narrow beams. If any beam of the set of beams detects frequent or continuous interference, the device may drop that beam from the concurrent LBT procedure.

Abstract: A user equipment (UE) may transmit a random access request message to a base station in a random access procedure to access a wireless network. In response, the base station may transmit a random access response message to the UE including an uplink grant for a first set of uplink resources for the UE to transmit a radio resource control (RRC) message. The UE may determine a second set of uplink resources for transmitting the RRC message, for example, based on additional uplink grants received in the random access response message. Additionally or alternatively, the UE may derive additional grants implicitly from the first uplink grant received from the base station. The UE may transmit the RRC message to the base station using the first and/or second sets of uplink resources and establish a connection based on the RRC message for subsequent uplink and downlink communications.

Abstract: Aspects described herein relate to receiving multiple synchronization signal block (SSB) signals from a base station, wherein the multiple SSB signals are each beamformed based on a different directional beam, selecting a signature from a signature space of a first SSB of the multiple SSB signals, and transmitting, based on the signature, a random access message to the base station, wherein the random access message includes an indicator of a preferred SSB of the multiple SSB signals.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may select, for a first message of a random access channel (RACH) procedure and based at least in part on whether the UE has beam correspondence, at least one of: a set of time-frequency resources for the first message of the RACH procedure, or a preamble for the first message of the RACH procedure. In some aspects, the UE may transmit, to a base station and based at least in part on selecting the at least one of the set of time-frequency resources or the preamble, the first message of the RACH procedure. Numerous other aspects are provided.