Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive an indication of a delta-frequency associated with a dual-tone downlink transmission from a network entity, the delta-frequency defining a frequency difference between two tones used for the dual-tone downlink transmission. The UE may receive the dual-tone downlink transmission from the network entity according to the two tones. The UE may decode the dual-tone downlink transmission based at least in part on the delta-frequency.

Abstract: Methods, systems, and devices for wireless communications are described. The described techniques provide for a network device to transfer energy to an energy harvesting (EH)-capable device via a multisine waveform. The network device may transmit the multisine waveform according to a multisine waveform configuration that indicates frequency locations for each EH channel of the multisine waveform across a channel bandwidth. In some cases, the network device may determine the multisine waveform configuration according to latency information of the passive IoT device, channel quality measurements for the channel bandwidth, or both. The multisine waveform configuration may indicate a distribution of individual EH channels across the channel bandwidth to improve frequency diversity, may indicate a contiguous grouping of EH channels to improve multisine gain, or a combination thereof.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit a random access preamble to a network entity via a random access occasion. The UE may then receive a first downlink message that indicates a temporary radio network identifier that is associated with the random access preamble. The UE may further transmit a random access message that includes the temporary radio network identifier indicated via the first downlink message and information associated with a contention resolution identity associated with the UE. Moreover, the UE may receive a second downlink message. In some cases, the second downlink message may include a radio network identifier corresponding to a contention resolution identity that is associated with the UE or a second UE that is different from the UE. Additionally, or alternatively, the second downlink message may include a request for a retransmission of the random access message.

Abstract: A method for wireless communication by a user equipment (UE) includes transmitting, to a network node, a first message indicating a capability of the UE to transmit a multiplexed low peak-to-average power ratio (PAPR) demodulation reference signal (DM-RS) and a high PAPR reference signal (RS) within a single slot, the low PAPR DM-RS having a first waveform and the high PAPR RS having a second waveform. The method also includes multiplexing, associated with the capability, the low PAPR DM-RS with the high PAPR RS within the single slot. The method further includes transmitting, to the network node, the multiplexed low PAPR DM-RS and high PAPR RS within the single slot.

Abstract: The apparatus may be a UE configured to transmit, via a first set of resources associated with a first RO, a first random access message (Msg 1) using a first preamble sequence, transmit, via a second set of resources associated with a second RO, an additional first random access message (additional Msg 1) using a second preamble sequence associated with a first cyclic shift value that indicates support for a capability of the UE, wherein the additional Msg 1 is based on the Msg 1, and receive a second random access message (Msg 2) based on the Msg 1 and the additional Msg 1.

Abstract: Certain aspects of the present disclosure provide techniques for wireless communication by an apparatus. A method includes receiving a synchronization signal, the synchronization signal including timing information associated with a directional beam sweep procedure, and power threshold information indicating beam power criteria evaluated during the directional beam sweep procedure; receiving, from the directional beam sweep, a first directional beam in accordance with the timing information, the first directional beam providing radio frequency energy for energy harvesting by the apparatus; measuring an amount of power associated with the first directional beam; comparing the measured amount of power to the power threshold information; and providing a feedback signal, wherein the contents of the feedback signal are based on the comparison with the power threshold information associated with the directional beam sweep.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a phase sweeping procedure involves a first network node transmitting a first signal at a first phase while one or more second network nodes transmit a plurality of second signals at a plurality of second phases. In some aspects, the phase sweeping procedure may produce a plurality of combined signals, each combined signal a combination of the first signal and at least one of the plurality of second signals. For example, the first signal and the one or more second signals may constructively interfere with each other to produce a signal of sufficient energy to be received by an ambient internet of things (IoT) device. The ambient IoT device may transmit, to a network node, an indication of a received signal power associated with the combined signal.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a mobile station may receive, based at least in part on a time-frequency domain resource block that is characterized at least by a frequency span and a time duration, a wireless signal that comprises: a first modulated portion located in a first partition of the time-frequency domain resource block, the first modulated portion being based at least in part on an orthogonal time frequency space (OTFS) modulation scheme, and a second modulated portion located in a second partition of the time-frequency domain resource block, the second modulated portion being based at least in part on a second modulation scheme. The mobile station may recover a channel state information reference signal (CSI-RS) from the first modulated portion or the second modulated portion. Numerous other aspects are described.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a first network entity may transmit, to a second network entity, a first random access communication including a random access preamble. The first network entity may receive, from the second network entity, a second random access communication including an identifier indicative of the random access preamble, and a first resource allocation. The first network entity may receive, from the second network entity, a third random access communication including the identifier, and indicating a second resource allocation. The first network entity may transmit, to the second network entity, a fourth random access communication via a particular resource allocation, wherein the particular resource is either the first resource allocation or the second resource allocation. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. A first wireless device (e.g., a network entity) may obtain, from multiple second wireless devices (e.g., user equipments (UEs)), multiple message segments via multiple slots. The first wireless device may assign each obtained message segment to a respective channel estimate cluster of multiple channel estimate clusters. A first set of the multiple message segments may be associated with a first channel estimate cluster, and may collectively form a first message. The first message may be associated with a second wireless device of the multiple second wireless devices. The first wireless device may decode the first message. In some examples, the first wireless device may decode a second message associated with a second channel estimate cluster of a second set of multiple message segments.

Abstract: Certain aspects of the present disclosure provide techniques for backscatter communications. An example method includes sending, to a first set of backscatter devices, one or more first signals via a first transmit beam at a first transmit power in one or more first transmission occasions; and sending, to a second set of backscatter devices, one or more second signals via a second transmit beam at a second transmit power in one or more second transmission occasions.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. Some aspects more specifically relate to multiplexing ambient internet of things (IoT) waveforms and user equipment (UE) reference signals. In some aspects, a network node may transmit, to an ambient IoT device and a UE, an ambient IoT waveform multiplexed with a UE reference signal. For example, the network node may transmit the ambient IoT waveform multiplexed with the UE reference signal in accordance with various implementations for multiplexing the ambient IoT waveform with the UE reference signal.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit one or more requests to initiate transmission of a multiple-network-node power signal that uses a first network node and at least a second network node. The UE may receive the multiple-network-node power signal that uses the first network node and at least the second network node. Numerous other aspects are described.

Abstract: Methods, systems, and devices for wireless communications are described. A network entity may configure one or more random access channel (RACH) resource sets and a user equipment (UE) may receive a configuration message from the network entity. The configuration message may indicate multiple RACH resource sets for the UE. Each RACH resource set may be associated with a respective range of targeted uplink power values, with a respective quantity of random access occasions, with a respective RACH format, or a combination thereof. The UE may select a RACH resource set from the configured RACH resource sets based on an uplink power value associated with the UE. The UE may transmit one or more random access messages to the network entity in accordance with the selected RACH resource set.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may use information related to a previously-transmitted random access preamble to determine whether a collision for the preamble exists, and the UE may transmit a subsequent random access message using resources selected in accordance with the determination. For example, the UE may receive a message that indicates path information for respective random access preambles detected by the network node. In some examples, the path information may indicate allocated resources for respective paths corresponding to the detected random access preambles. The UE may determine whether a collision exists for a path corresponding to the previously-transmitted random access preamble. The UE may transmit the subsequent random access message using a first set of resources (e.g., contention-based resources), a second set of resources (e.g.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. Some aspects more specifically relate to ambient device random access message transmissions. A network node may transmit, and an ambient device may receive, configuration information that indicates a minimum permitted duration and a maximum permitted duration for transmitting a random access message. A reader device may transmit a query message to the ambient device. The ambient device may transmit, and the reader device may receive, a random access message that includes a pseudorandom noise sequence and a redundancy sequence. The redundancy sequence may include a portion of the pseudorandom noise sequence. A duration of the redundancy sequence may be in accordance with the minimum permitted duration and the maximum permitted duration. For example, the duration of the redundancy sequence may be equal to the maximum permitted duration subtracted by the minimum permitted duration.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a reader may transmit a first wireless communication signal to a first group of ambient internet of things (IoT) devices. The first group of ambient IoT devices may transmit a response to the signal based at least in part on being located within a first range of distances from the reader and the first signal being transmitted at a first transmit power. The reader may transmit a second wireless communication signal to a second group of ambient IoT devices. The second group of ambient IoT devices may transmit a response to the signal based at least in part on being located within a second range of distances from the reader and the signal being transmitted at a second transmit power. Numerous other aspects are described.

Abstract: This disclosure provides methods and apparatuses for maintaining phase continuity and optimizing channel estimation in wireless communication systems using multiple coherent demodulation reference signal (DMRS) ports through a glue reference signal (gRS). In various examples, an apparatus for wireless communication such as a UE or network entity may obtain or send, in a first time span, a first reference signal associated with multiple coherent ports in a code division multiplexing (CDM) group; obtain or send, in a second time span prior to the first time span, a second reference signal for compensation of a phase change across a gap between start and length indicator values (SLIVs) or within an SLIV; obtain or send, in the second time span, a third reference signal; and obtain or send a shared channel based on these signals. The methods and apparatuses provide enhanced phase continuity and accurate channel estimation, improving system performance and efficiency.

Abstract: Methods, systems, and devices for wireless communications are described. A user equipment (UE) may transmit a random access preamble via a random access occasion (RO) in accordance with a cyclic shift (CS) and a CS offset. The UE may receive, from a network entity, a first response message that indicates information associated with one or more random access paths detected by a network entity within a threshold duration. The UE may determine whether one or more collisions occur based on the information and may refrain from transmitting a random access message when two or more estimated random access paths are detected within a threshold duration of its CS and CS offset. The UE may receive a second response message based on refraining from transmitting the random access message. The UE may establish a connection with the network entity based on receiving the second response message.

Abstract: Techniques for collision resolution in Ambient Internet of Things (A-IoT) communications are described. A reader device obtains sampling frequency offset (SFO) indications for received random access messages and generates collision indicators based on the SFOs. The reader device may then allocate resources for subsequent transmissions using various strategies, such as omitting allocations for colliding devices, providing multiple allocations, or matching allocations to specific SFO values. A-IoT devices receive these allocations along with collision indicators and adjust their subsequent transmissions accordingly, either by selecting from multiple resources or generating new access sequences. This approach enables efficient collision handling while accommodating the limitations of low-complexity A-IoT devices.