Patent Description:
<CIT> discloses an enhanced node B (eNB), user equipment (UE) and methods of signaling for proximity services and device-to-device (D2D) discovery in an LTE network. The eNB may transmit signaling to indicate D2D discovery zone configuration to proximity service (ProSe) enabled UEs. The signaling may indicate time and frequency resources and a periodicity of a discovery zone and may indicate operational parameters for the discovery zone. The resources of the D2D discovery zone may be allocated for D2D discovery signal transmission by the ProSe-enabled UEs.

<CIT> discloses communication systems, methods, apparatus and techniques, and particularly to methods, apparatus and techniques for device or peer discovery in wireless communication systems (such as, for example, cellular networks) which support both direct communication and cellular network communication.

<NPL>) discloses potential solutions of DRS design to support LAA RRM functionalities.

For UEs communicating through a sidelink (SL) channel, discovery signals can be measured (e.g., in terms of reference signal received power (RSRP), reference signal received quality (RSRQ), etc.) to identify candidate UEs for SL communication. From among a set of identified candidate UEs, a particular UE can be selected based on the measured discovery signals. For example, a UE transmitting a particular set of discovery signals measured to be the best (e.g., to have a highest or lowest value, depending on what is being measured) may be selected for SL communication. In order to efficiently use SL bandwidth, it may be useful to not measure unnecessary discovery signals given a set of current conditions.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a first device at a first UE. The first device may be a processor and/or modem at a user equipment (UE) or the UE itself. The first device may be configured to receive a set of discovery channel measurement time configurations (DMTCs) from a second device (e.g., at a second UE). The first device may further be configured to receive information indicating a DMTC of the set of DMTCs to be used for measuring discovery signals. The first device may be configured to measure discovery signals received from the second UE based on the indicated DMTC.

The DMTC may specify a duration and a periodicity of discovery signals. In some aspects, a set of DMTCs may be received in configuration information (e.g., radio resource control (RRC) information from a base station) such that a given DMTC to be used for measuring discovery signals can be identified by identifying a pre-configured DMTC in the received configuration information (e.g., in a received table of pre-configured DMTCs). A particular pre-configured DMTC may be designated as a default DMTC in some configurations. In some aspects, additional configuration information may be received by the first device. The additional configuration information may include a carrier through which the discovery signals will be measured, a bandwidth part (BWP) through which the discovery signals will be measured, a resource pool through which the discovery signals will be measured, and a numerology used to measure the discovery signals. The carrier, BWP, resource pool, or numerology of the discovery signals to be measured may be the same as, or different from, the carrier, BWP (e.g., the active BWP), resource pool, or numerology through which the first device communicates with the second device.

The first device may further be configured to transmit a recommendation to the second device to switch from a current DMTC to a different DMTC. The transmission of the recommendation, in some aspects, may be based on a determination that mobility conditions associated with the first device are greater than a first UE mobility threshold or less than a second UE mobility threshold. The recommendation may be UE mobility conditions associated with the first device and/or a DMTC identifier identifying a DMTC in the set of received DMTCs.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a second device at a second UE. The second device may be a processor and/or modem at a user equipment (UE) or the UE itself. The second device may be configured to transmit a set of discovery channel measurement time configurations (DMTCs) to the first device. The second device may further be configured to transmit information indicating a DMTC of the set of DMTCs to be used by the first UE for measuring discovery signals. The second device may be configured to transmit discovery signals to the first UE for the first UE to measure based on the indicated DMTC.

In some aspects, the second device may also receive a set of DMTCs in configuration information (e.g., RRC information from a base station) such that a given DMTC to be used for measuring discovery signals at the first UE can be identified by identifying a pre-configured DMTC in the received configuration information (e.g., in a received table of pre-configured DMTCs). In some aspects, the second device may be configured to transmit the set of DMTCs to the first device after receiving it from a base station. A particular pre-configured DMTC may be designated as a default DMTC in some configurations. In some aspects, additional configuration information may be transmitted to the first device. The additional configuration information may include a carrier through which the discovery signals will be measured, a BWP through which the discovery signals will be measured, a resource pool through which the discovery signals will be measured, and a numerology used to measure the discovery signals. The carrier, BWP, resource pool, or numerology of the discovery signals to be measured may be the same as, or different from, the carrier, BWP, resource pool, or numerology through which the first device communicates with the second device.

The second device may further be configured to receive a recommendation from the first device to switch from a current DMTC to a different DMTC. The transmission of the information indicating the DMTC of the set of DMTCs to be used for measuring discovery signals at the first UE may be transmitted in response to the received DMTC recommendation.

The communication links <NUM> may use multiple-in put and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. Allocation of carriers may be asymmetric with respectto DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL).

The small cell <NUM>', employing NR in an unlicens e d frequency spectrum, may boost coverage to and/or increase capacity of the access network.

The UPF <NUM> provides UEIP address allocation as well as other functions.

The UE <NUM> may also be referredto as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

Referring again to <FIG>, in certain aspects, the UE <NUM> may include a discovery channel measurement component <NUM> that is configured to receive, from a second UE, a set of discovery channel measurement time configurations (DMTCs); receive information indicating a DMTC of the set of DMTCs to be used for measuring discovery signals; and measure discovery signals received from the second UE based on the indicated DMTC configuration. Referring again to <FIG>, in certain aspects, the UE <NUM> may include an adaptive discovery channel measurement component <NUM> that is configured to transmit, to a first UE, a set of discovery channel measurement time configurations (DMTCs); transmit, to the first UE, information indicating a DMTC of the set of DMTCs to be used by the first UE for measuring discovery signals; and transmit discovery signals to the first UE for the first UE to measure based on the indicated DMTC. One of ordinary skill in the art will appreciate that discovery signals may be transmitted by a UE (e.g., a UE <NUM> including adaptive discovery channel measurement component <NUM>) in addition to those transmitted during a time indicated by information indicating a DMTC to a different UE (e.g., a UE <NUM> including discovery channel measurement component <NUM>).

The symbols on DL may be cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. For slot configuration <NUM>, different numerologies µ <NUM> to <NUM> allow for <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> slots, respectively, per subframe. <FIG> provide an example of slot configuration <NUM> with <NUM> symbols per slot and numerology µ=<NUM> with <NUM> slots per subframe. The slot duration is <NUM>, the subcarrier spacing is <NUM>, and the symbol duration is approximately <NUM>. Within a set of frames, there may be one or more different bandwidth parts (BWPs) (see <FIG>) that are frequency division multiplexed. Each BWP may have a particular numerology.

The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs) (e.g., <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> CCEs), each CCE including six RE groups (REGs), each REG including <NUM> consecutive REs in an OFDM symbol of an RB. A PDCCH within one BWP may be referred to as a control resource set (CORESET). A UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at greater and/or lower frequencies across the channel bandwidth. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS)/PBCH block (also referred to as SS block (SSB)).

The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgment (ACK) (HARQ-ACK) information (ACK / negative ACK (NACK)) feedback.

Each spatial stream may then be provided to a different antenna <NUM> via a separate transmitter <NUM> TX. Each transmitter <NUM> TX may modulate an RF carrier with a respective spatial stream for transmission.

At the UE <NUM>, each receiver <NUM> RX receives a signal through its respective antenna <NUM>. Each receiver <NUM> RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor <NUM>.

The spatial streams generated by the TX processor <NUM> may be provided to different antenna <NUM> via separate transmitters <NUM> TX. Each transmitter <NUM> TX may modulate an RF carrier with a respective spatial stream for transmission.

Each receiver <NUM> RX receives a signal through its respective antenna <NUM>. Each receiver <NUM> RX recovers information modulated onto an RF carrier and provides the information to a RX processor <NUM>.

In 5GNR, UEs can communicate directly. In order to facilitate direct communication, UEs may transmit and receive discovery signals. The periodicity and the duration of the discovery signals (also referred to as discovery reference signals) may be defined in a discovery reference signal (DRS) (or discovery channel) measurement time configuration (DMTC). Under different conditions (e.g., different UE mobility conditions), different periodicity and duration may be sufficient for discovery signal measurement. Accordingly, there is benefit to introducing adaptive DMTC to reduce power usage for a UE measuring, or transmitting, discovery signals, and to use communication resources more efficiently.

<FIG> is a call flow diagram <NUM> illustrating the use of adaptive DMTCs. As illustrated in <FIG>, a first UE <NUM> (i.e., UE A), in some configurations, may transmit a solicitation signal <NUM> to a set of other UEs <NUM> (i.e., UEs B-D) to establish a connection with the other UEs <NUM> to communicate through the UE <NUM> (e.g., as a relay) to a base station (e.g., an eNB or gNB). The receiving UEs <NUM> may measure the discovery signals (e.g., measure a reference signal received power (RSRP), reference signal received quality (RSRQ), etc. of the discovery signals). The receiving UEs may determine that the measurement meets a threshold for responding at <NUM> or that the measurement does not meet a threshold for responding at <NUM>. The UEs <NUM> for which the measurement meets the threshold, at <NUM>, then respond <NUM> to UE <NUM>. Alternatively, in some embodiments, each UE <NUM> that is available to serve as a relay to a base station may periodically transmit an announcement message <NUM>. UE <NUM> may measure, at <NUM>, the discovery signals received from the other UEs <NUM> (e.g., UEs B and C) and may select a UE based on the measurement and a set of criteria. Once a UE <NUM> (e.g., UE B) is selected, a sidelink communication session can be established and SL communication <NUM> may be exchanged with UE B <NUM> (e.g., a second UE). For example, SL communication between UE A <NUM> and UE B402 may be through a PC5 interface.

In some configurations, a UE <NUM> may transmit a DMTC recommendation <NUM> to the connected UE <NUM> to adjust a DMTC (e.g., to switch from a first DMTC to a second DMTC). In some configurations, the recommendation may specify a particular DMTC from a set of pre-configured DMTCs. In other configurations, the UE <NUM> may transmit a set of characteristics of the UE <NUM> on which the connected UE <NUM> can base a decision to adjust a DMTC. The recommendation, in some configurations, may be based on the UE <NUM> determining that some characteristic of the UE <NUM> has changed (e.g., a measure of the UE's mobility has crossed a threshold value). For example, a UE <NUM> may transmit information regarding a mobility of the UE (e.g., that the mobility is between a set of threshold values, that the mobility exceeds (or is below) a particular threshold value, etc.) on which a connected UE <NUM> may base a decision to adjust a periodicity or duration of discovery signals. A periodicity may be adjusted to maintain the quality of the connection by increasing the frequency of discovery signals or to conserver power by limiting the amount of time the UE <NUM> may need to monitor discovery signals by decreasing the frequency of discovery signals. DMTC recommendation <NUM> may be transmitted by UE A <NUM> and received by UE B <NUM> through a PC5 interface.

Based on the recommendation, or on other criteria in the absence of a recommendation <NUM>, the connected UE <NUM> may determine that the DMTC should be adjusted at <NUM>. The connected UE <NUM> may transmit a DMTC adjustment message <NUM> that is received by UE <NUM>. The DMTC adjustment message <NUM> may identify a pre-configured DMTC or provide a set of configuration information including information regarding periodicity, duration, timing (e.g., frame, subframe, slot, symbol, etc.), carrier, BWP, or specific resources used for the discovery signals. The DMTC adjustment message may be transmitted by UE <NUM> and received by UE <NUM> through sidelink control information (SCI) (e.g., SCI-<NUM>) or through a media access control (MAC) control element (CE) (MAC-CE) through a PC5 interface (e.g., an interface for D2D communication) or physical sidelink feedback channel (PSFCH).

The UE <NUM> may begin to monitor for discovery signals, at <NUM>, using the information provided in the received DMTC adjustment message. After transmitting the DMTC adjustment message <NUM>, the UE <NUM> may transmit discovery signals using the adjusted DMTC <NUM>. One of ordinary skill in the art will appreciate that communications <NUM> may continue to be exchanged throughout and that communications and operations <NUM>-<NUM> may be performed multiple times as conditions change for either UE <NUM> or <NUM>.

<FIG> is a call flow diagram <NUM> illustrating the use of pre-configured DMTCs <NUM>. Base station <NUM> may transmit RRC signals 504A and 504B to a first UE <NUM> and a second UE <NUM>. RRC signals 504A-C may include a set of pre-configured DMTCs <NUM> that may define a set of DMTCs by specifying a DMTC identifier (ID) that is associated with a duration and periodicity of the discovery signals. In addition to the duration and the periodicity of the discovery signals, some configurations may associate information with a DMTC ID that includes a carrier, a BWP, a resource pool, a measurement gap, and/or numerology associated with the DMTC as described in relation to <FIG> below. In some configurations, UE <NUM> may not receive RRC signal 504A (because it is not connected to base station <NUM>) and instead may receive RRC signal 504C from the second UE <NUM>. UE <NUM> may be transmitting the RRC signal 504C independently or acting as a relay from base station <NUM>. In some configurations, instead of RRC signals, the set of DMTCs may be transmitted through system information.

At <NUM>, the first UE <NUM> may use DMTC_1 for receiving and measuring discovery signals. In some configurations, the use of DMTC_1 may be based on a designation of DMTC_1 as a default DMTC. A sidelink communication session having been established and a DMTC selected, SL communication <NUM> may be exchanged with the second UE <NUM> through a PC5 interface.

In some configurations, the first UE <NUM> may transmit a DMTC recommendation 509A to the connected second UE <NUM> to adjust a DMTC. The DMTC recommendation 509A may be transmitted to the connected second UE <NUM> through a PC5 interface. Alternatively, the DMTC recommendation may be transmitted as DMTC recommendation 509B to base station <NUM> which may in turn communicate the recommendation to the second UE <NUM> as DMTC recommendation 509C. DMTC recommendations 509B and 509C may be transmitted through Uu interfaces (e. g interfaces for UE to BS communication) between the UEs <NUM> and <NUM> and base station <NUM>. The recommendation may specify a particular DMTC from the set of pre-configured DMTCs <NUM>. The recommendation, in some configurations, may be based on the first UE <NUM> determining that some characteristic of the first UE <NUM> has changed (e.g., a measure of the UE's mobility has crossed a threshold value). For example, the first UE <NUM> may transmit the DMTC recommendation 509A or 509B based on detecting that the mobility of the first UE <NUM> is now between a set of threshold values that it was not between before, or that the mobility exceeds (or is below) a particular threshold value.

Based on the recommendation, or on other criteria in the absence of a recommendation 509A and/or 509B and 509C, the connected second UE <NUM> may determine that the DMTC should be adjusted at <NUM>. The connected UE <NUM> may transmit a DMTC adjustment message <NUM> that is received by the first UE <NUM>. The DMTC adjustment message <NUM> may identify a pre-configured DMTC and a set of configuration information including information regarding timing (e.g., frame/subframe/slot/symbol), carrier, BWP, or specific resources used for the discovery signals. The DMTC adjustment message may be transmitted by UE <NUM> and received by UE <NUM> through SCI or through a MAC-CE through a PC5 interface. The UE <NUM> may begin to monitor for discovery signals, at <NUM>, using the information provided in the received DMTC adjustment message. After transmitting the DMTC adjustment message <NUM>, the second UE <NUM> may transmit discovery signals <NUM> to be measured based on the adjusted DMTC (e.g., DMTC_2). One of ordinary skill in the art will appreciate that communications <NUM> may continue to be exchanged throughout and that communications and operations <NUM>-<NUM> may be performed multiple times as conditions change for either UE <NUM> or <NUM>.

<FIG> is a diagram <NUM> illustrating an example of a first DMTC. <FIG> is a diagram <NUM> illustrating an example of a second DMTC. <FIG> is a diagram <NUM> illustrating sets of resource pools through which different UEs are assigned for communicating and through one of which discovery signals are transmitted. <FIG> illustrates a first DMTC that may specify a duration <NUM> and a periodicity <NUM> for discovery signals <NUM> in a carrier or BWP <NUM> (e.g., an active carrier or BWP used for SL communication). As shown, the discovery signals <NUM> may occupy the whole carrier or BWP <NUM>. However, in some configurations, the discovery signals <NUM> may occupy a portion of the carrier or BWP <NUM>. <FIG> illustrates a second DMTC in a second carrier or BWP <NUM> that may specify a same duration <NUM> as duration <NUM>, but also may specify a different periodicity <NUM> than periodicity <NUM>. In some configurations, the periodicity and the duration can vary independently and different configurations may specify either the same periodicity or the same duration with corresponding different durations and periodicities, respectively.

<FIG> illustrates a first resource pool (RP-<NUM>) <NUM> through which a first UE may transmit and receive sidelink (SL) data and a second resource pool (RP-<NUM>) <NUM> through which a second UE may transmit and receive SL data and through which discovery signals can be transmitted and received. As shown, RP <NUM> and RP <NUM> may include first and second distinct sets of resources, respectively, in a carrier or BWP <NUM> in a time-and-frequency resource space. In some configurations, RP <NUM> and RP <NUM> may overlap (partially or completely) in time and/or frequency (i.e., may include resources that overlap in at least one of time or frequency). RP <NUM> and RP <NUM> may include different amounts or assigned resources. One of ordinary skill in the art will appreciate that either or both of the RPs assigned to SL communication and the discovery signals can span all or a portion of the frequencies of carrier or BWP <NUM> and that, in some configurations, the frequencies may be in a same carrier or BWP but the span of frequencies for the SL communication and the discovery signals may not have any common frequencies.

<FIG> is a diagram <NUM> illustrating an example of a measurement gap <NUM> based on a change in numerology between SL communication <NUM> and discovery signals <NUM>. <FIG> is a diagram <NUM> illustrating an example of a measurement gap <NUM> based on a change in carrier or BWP between SL communication <NUM> and discovery signals <NUM>.

<FIG> illustrates a carrier or BWP <NUM> that includes a set of frequency resources that are used by the discovery signals and a set of frequency resources that are used by the UE for SL communication. As shown, SL communication <NUM> may span all the frequencies of the carrier or BWP <NUM>, while the discovery signals <NUM> may span a subset of the frequencies of the carrier or BWP <NUM>. In <FIG>, SL communications <NUM> may use a first numerology µ=<NUM> and discovery signals <NUM> may use a second numerology µ=<NUM> (where a numerology determines a subcarrier spacing and slot/symbol duration for the transmission and reception of signals). A UE that is transmitting and receiving signals and/or data using a first numerology (µ=<NUM>) may receive a discovery signal using a second numerology (µ=<NUM>). During the time that the UE receives discovery signals <NUM> (e.g., during measurement gaps <NUM>) the UE may not be available to receive SL data communication <NUM> (e.g., data communication that is not discovery signals). For example, different processing may be used for the SL communications <NUM> received using a first numerology (µ=<NUM>) and for the discovery signals <NUM> using a second, different numerology (µ=<NUM>). Accordingly, the UE may refrain from transmitting or receiving data communication when performing the channel measurements on the discovery signals received from the second UE during the measurement gap <NUM>.

Similarly, <FIG> illustrates a first carrier or BWP <NUM> through which SL communications are transmitted and/or received and a second carrier or BWP <NUM> through which discovery signals are transmitted and/or received. A UE that is transmitting and receiving signals and/or data through the first carrier or BWP <NUM> may receive a discovery signal through the second carrier or BWP <NUM>. During the time that the UE receives the discovery signal <NUM> through the second carrier or BWP <NUM> the UE may not be available to receive SL data communication <NUM> (e.g., data communication that is not discovery signals). Accordingly, the UE may refrain from transmitting or receiving data communication <NUM> when performing the channel measurements on the discovery signals received from the second UE during the measurement gap <NUM>.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a device at a UE (e.g., UE <NUM>/<NUM>). The device may be a processor/modem within the UE <NUM>/<NUM> or the UE <NUM>/<NUM> itself. The device is herein referred to as a first UE. Optional aspects are illustrated with a dashed line. In one configuration, the first UE may receive, at <NUM>, a set of one or more DMTCs. For example, <NUM> may be performed by <NUM> in <FIG>. The set of DMTCs, in some configurations, is a set of pre-configured DMTCs (e.g., pre-configured DMTCs <NUM>) as shown in <FIG> that define a set of DMTCs by specifying a DMTC ID that is associated with a duration and periodicity of the discovery signals. In addition to the duration and periodicity of the discovery signals, some configurations may associate information with a DMTC ID that includes a carrier, a BWP, a resource pool, a measurement gap, and/or numerology associated with the DMTC as described in relation to <FIG>. The set of DMTCs may be received from a second UE (e.g., UE <NUM>) or a base station (e.g., base station <NUM>). The DMTCs may be received through RRC signaling (e.g., RRC signal 504A and/or 504C) or system information.

The first UE, at <NUM>, may measure discovery signals received from the second UE based on a first DMTC, in some configurations. For example, <NUM> may be performed by <NUM> in <FIG>. The first DMTC, in some configurations, is a particular configuration in the set of DMTCs (e.g., set of DMTCs <NUM>) that is a default configuration. For example, UE <NUM> of <FIG> uses default DMTC "DMTC_1" until a DMTC adjustment message <NUM> that indicates a different DMTC (e.g., DMTC_2) is received.

In one configuration, the first UE and second UE may communicate, at <NUM>, through at least one of a physical sidelink shared channel (PSSCH) or physical sidelink control channel (PSCCH) through a first carrier (e.g., <NUM>, <NUM>, <NUM>), BWP (e.g., <NUM>, <NUM>, <NUM>), and/or resource pool (e.g., <NUM> or <NUM>) and using a first numerology (e.g., <NUM>, <NUM>, N) as illustrated by, and discussed in relation to, <FIG>. For example, <NUM> may be performed by <NUM> in <FIG>. The discovery signals are transmitted through a second carrier (e.g., <NUM>, <NUM>, <NUM>), BWP (e.g., <NUM>, <NUM>, <NUM>), and/or resource pool (e.g., <NUM> or <NUM>) and using a second numerology (e.g., <NUM>, <NUM>, N) as in <FIG>. The second carrier, BWP, resource pool and/or numerology can be the same as, or different from, the first carrier, BWP, resource pool and/or numerology as illustrated by, and discussed in relation to, <FIG>.

In one configuration, the first UE may determine, at <NUM>, whether the UE should transmit a DMTC-adjustment recommendation to the second UE. For example, <NUM> may be performed by <NUM> in <FIG>. The determination, at <NUM>, may be based on detecting that a mobility of the first UE has crossed a threshold mobility (e.g., one of a set of thresholds). Alternatively, or additionally, the determination, at <NUM>, may be based on a mobility value of the first UE being greater than a first UE mobility threshold (e.g., a value indicating that the UE is moving quickly) or less than a second UE mobility threshold (e.g., a value indicating that the UE is moving slowly or is not moving). The first and second UE mobility threshold may depend on a UE mobility value associated with the UE at the time the use of a current DMTC was initiated. For example, a first mobility value measured at the time the use of the current DMTC was initiated may fall into a range of values for which the current DMTC is appropriate and the first and second mobility thresholds are determined to be the upper and lower bounds of the range.

In configurations that determine whether the UE should transmit a DMTC-adjustment recommendation, if the first UE determines, at <NUM>, that the first UE should transmit a DMTC-adjustment recommendation, the first UE in some configurations may, at <NUM>, determine a recommended DMTC. Determining the recommended DMTC may be based on the UE mobility value or a UE mobility threshold crossed. For example, a first UE mobility value (or crossing a first UE mobility threshold) indicating fast movement of the UE may trigger a DMTC with a shorter periodicity, while, a second UE mobility value (or crossing a second UE mobility threshold) indicating slow movement of the UE may trigger a DMTC with a longer periodicity. For example, <NUM> may be performed by <NUM> in <FIG>.

After determining, at <NUM>, a recommended DMTC, the first UE may transmit a DMTC recommendation to the second UE at <NUM>. For example, <NUM> may be performed by <NUM> in <FIG>. Transmitting the determined recommended DMTC may include transmitting (<NUM>) a DMTC ID identifying a DMTC in the set of DMTCs received, at <NUM>, by the first UE or (<NUM>) a mobility value associated with the first UE. Alternatively, if the first UE has not received a set of DMTCs, the DMTC recommendation may include the UE mobility value or an indication that the UE mobility value is greater than a first UE mobility threshold or is less than a second UE mobility threshold. Additionally, in some configurations that do not determine a recommended DMTC at <NUM>, the DMTC recommendation transmitted at <NUM> may include the UE mobility value or an indication that the UE mobility value is greater than a first UE mobility threshold or is less than a second UE mobility threshold. The second UE can then use the DMTC recommendation to determine an appropriate DMTC as will be discussed in relation to <FIG> below.

If the first UE determines, at <NUM>, that no DMTC-adjustment should be transmitted, <FIG> illustrates that the process may continue by receiving, at <NUM>, information from the second UE indicating a DMTC of the set of DMTCs to be used for measuring discovery signals. The DMTC adjustment message may be received through SCI or through a MAC-CE through a PC5 interface. However, one of ordinary skill in the art will understand that the determination made at <NUM>, in some instances will include multiple determinations made periodically or based on certain events (e.g., a detected change in a mobility value) before receiving the information from the second UE indicating a DMTC of the set of DMTCs to be used for measuring discovery signals.

At <NUM>, the first UE may receive information from the second UE indicating a DMTC of the set of DMTCs to be used for measuring discovery signals. For example, <NUM> may be performed by <NUM> in <FIG>. The DMTC may be indicated by providing the DMTC ID associated with the DMTC. Alternatively, if no set of DMTCs is received at <NUM>, the information indicating the DMTC includes a set of timing information for the second DMTC (e.g., a duration, periodicity, and temporal location of the discovery signals). In addition to the information indicating the DMTC, some configurations may transmit information that includes a carrier, a BWP, a resource pool, a measurement gap, and/or numerology associated with the discovery signals as described in relation to <FIG>. The received information indicating the DMTC to be used for measuring discovery signals, may or may not be in response to a DMTC recommendation transmitted, at <NUM>, by the first UE as will be discussed in relation to <FIG> below. After receiving, at <NUM>, the information indicating the DMTC, the first UE measures, at <NUM>, discovery signals based on the indicated DMTC. For example, <NUM> may be performed by <NUM> in <FIG>.

<FIG> is a flowchart <NUM> of a method of wireless communication. The method may be performed by a device at a UE <NUM>/<NUM>. The device may be a processor/modem within the UE <NUM>/<NUM> or the UE <NUM>/<NUM> itself. The device is herein referred to as a second UE. Optional aspects are illustrated with a dashed line. In one configuration, the second UE may receive, at <NUM>, a set of one or more DMTCs. For example, <NUM> may be performed by <NUM> in <FIG>. The set of DMTCs, in some configurations, is a set of pre-configured DMTCs (e.g., pre-configured DMTCs <NUM>) as shown in <FIG> that define a set of DMTCs by specifying a DMTC ID that is associated with a duration and periodicity of the discovery signals. In addition to the duration and periodicity of the discovery signals, some configurations may associate information with a DMTC ID that includes a carrier, a BWP, a resource pool, a measurement gap, and/or numerology associated with the DMTC as described in relation to <FIG>. The set of DMTCs may be received from a base station (e.g., base station <NUM>). The DMTCs may be received through RRC signaling (e.g., RRC signal 504B) or system information.

The second UE, at <NUM>, may transmit a set of DMTCs to a first UE (e.g., UE <NUM>/<NUM>). For example, <NUM> may be performed by <NUM> in <FIG>. The transmitted set of DMTCs, in some configurations is the set of DMTCs (e.g., the set of pre-configured DMTCs <NUM>) received from a base station (e.g., base station <NUM>). In other configurations the set of DMTCs is determined by the second UE (e.g., UE <NUM>/<NUM>). The set of DMTCs define a set of DMTCs by specifying a DMTC ID that is associated with a duration and periodicity of the discovery signals. In addition to the duration and periodicity of the discovery signals, some configurations may associate information with a DMTC ID that includes a carrier, a BWP, a resource pool, a measurement gap, and/or numerology associated with the DMTC as described in relation to <FIG>. The DMTCs may be received through RRC signaling (e.g., RRC signal 504C) or system information.

In some configurations, the second UE, at <NUM>, may transmit discovery signals to the first UE for the first UE to measure based on a first DMTC. For example, <NUM> may be performed by <NUM> in <FIG>. In some configurations, the first DMTC is a particular DMTC in the set of DMTCs (e.g., the set of DMTCs <NUM>) that is a default DMTC. In one configuration, the second UE communicates, at <NUM>, with the first UE (e.g., communication <NUM>/<NUM>) through at least one of a physical sidelink shared channel (PSSCH) or physical sidelink control channel (PSCCH) through a first carrier (e.g., <NUM>, <NUM>, <NUM>), BWP (e.g., <NUM>, <NUM>, <NUM>), and/or resource pool (e.g., <NUM> or <NUM>) and using a first numerology (e.g., <NUM>, <NUM>, N) as illustrated by, and discussed in relation to, <FIG>. For example, <NUM> may be performed by <NUM> in <FIG>. The discovery signals are transmitted through a second carrier (e.g., <NUM>, <NUM>, <NUM>), BWP (e.g., <NUM>, <NUM>, <NUM>), and/or resource pool (e.g., <NUM> or <NUM>) and using a second numerology (e.g., <NUM>, <NUM>, N) as in <FIG>. The second carrier, BWP, resource pool and/or numerology can be the same as, or different from, the first carrier, BWP, resource pool and/or numerology as illustrated by, and discussed in relation to, <FIG>.

In some configurations, the second UE may receive, at <NUM>, a DMTC recommendation (e.g., DMTC recommendation <NUM>/509A/509C) from the first UE (e.g., receives the DMTC recommendation transmitted by the first UE at <NUM>) or from a base station that communicates a recommendation from the first UE to the second UE (e.g., DMTC recommendations 509B communicated to a base station and 509C communicated to UE <NUM>). For example, <NUM> may be performed by <NUM> in <FIG>. The received DMTC recommendation, in some configurations, is a DMTC ID identifying a DMTC in the set of DMTCs received, at <NUM>, by the second UE. Alternatively, the DMTC recommendation may include the UE mobility value or an indication that the UE mobility value is greater than a second UE mobility threshold or is less than a first UE mobility threshold.

At <NUM>, the second UE may determine that the DMTC should be adjusted. If a DMTC recommendation was received at <NUM>, the determination may be based on the received DMTC recommendation. For example, <NUM> may be performed by <NUM> in <FIG>. For example, if the received DMTC recommendation includes information regarding a UE mobility that suggest that an adjustment to a current DMTC (the UE mobility is higher or lower than a threshold UE mobility associated with a current DMTC) may be beneficial (e.g., more efficient, more reliable, etc.), a determination to adjust the DMTC is made. Additionally, the second UE may determine that the DMTC should be adjusted based on measurements of reference signals transmitted by the first UE failing to meet a strength, quality, and/or timing specification (e.g., expressed as a threshold value). The second UE may further determine that the DMTC should be adjusted based on determining that one or more measured characteristics of sets of reference signals received at different times is changing faster than a first threshold rate (such that the periodicity of the discovery signals should be decreased) or more slowly than a second threshold rate (such that the periodicity of the discovery signals should be increased).

At <NUM>, the second UE may transmit information to the first UE indicating that measurements of discovery signals should be based on a particular DMTC (e.g., the DMTC determined at <NUM>). For example, <NUM> may be performed by <NUM> in <FIG>. The DMTC adjustment message may be transmitted through a MAC-CE, SCI, or PSFCH. If a set of DMTCs is transmitted at <NUM>, the particular DMTC may be indicated by providing the DMTC ID associated with the particular DMTC. Alternatively, if no set of DMTCs is received at <NUM>, the information indicating the particular DMTC includes a set of timing information for the particular DMTC (e.g., a duration, periodicity, and temporal location of the discovery signals). Additionally, the information indicating a DMTC, in some configurations may include a carrier, a BWP, a resource pool, a measurement gap, and/or numerology associated with the discovery signals as described in relation to <FIG>. After transmitting, at <NUM>, the information indicating the particular DMTC, the second UE transmits, at <NUM>, discovery signals for the UE to measure based on the indicated DMTC (e.g., as in communication <NUM> of <FIG>). For example, <NUM> may be performed by <NUM> in <FIG>.

The communication manager <NUM> includes a discovery channel measurement component <NUM> that is configured to allow the UE to adaptively measure discovery signals associated with a discovery channel using different DMTCs based on different (e.g., changing) conditions, e.g., as described in connection with operations <NUM>-<NUM> of <FIG>. Adaptive DMTC component <NUM> may be configured to receive, from a second UE, a set of DMTCs, as described in connection with <NUM> in <FIG>. Adaptive DMTC component <NUM> may also be configured to receive information indicating a DMTC of the set of DMTCs to be used for measuring discovery signals, as described in connection with <NUM> in <FIG>. Adaptive DMTC component <NUM> may also be configured to measure discovery signals received from the second UE based on the indicated DMTC configuration, as described in connection with <NUM> in <FIG>.

In one configuration, the apparatus <NUM>, and in particular the cellular baseband processor <NUM>, includes means for receiving, from a second apparatus, a set of DMTCs. The apparatus <NUM>, and in particular the cellular baseband processor <NUM>, further includes means for receiving information indicating that discovery signals should be measured based on a DMTC of the set of DMTCs. The apparatus <NUM>, and in particular the cellular baseband processor <NUM>, further includes means for measuring discovery signals received from the second UE based on the indicated DMTC. The aforementioned means may be one or more of the aforementioned components of the apparatus <NUM> configured to perform the functions recited by the aforementioned means. As described supra, the apparatus <NUM> may include the TX Processor <NUM>, the RX Processor <NUM>, and the controller/processor <NUM>.

The communication manager <NUM> includes an adaptive DMTC component <NUM> that allows the UE to adaptively indicate different DMTCs for a connected UE (e.g., UE <NUM>) based on different (e.g., changing) conditions, e.g., as described in connection with operations <NUM>-<NUM> of <FIG>. Adaptive DMTC component <NUM> may be configured to transmit, to a first UE, a set of DMTCs as described in connection with <NUM> in <FIG>. Adaptive DMTC component <NUM> may also be configured to transmit, to the first UE, information indicating a DMTC of the set of DMTCs to be used by the first UE for measuring discovery signals as described in connection with <NUM> in <FIG>. Adaptive DMTC component <NUM> may also be configured to transmit discovery signals to the first UE for the first UE to measure based on the indicated DMTC as described in connection with <NUM> in <FIG>. One of ordinary skill in the art will appreciate that, in addition to discovery signals measured by a particular other apparatus (e.g., <NUM>) based on a particular DMTC, apparatus <NUM> may transmit additional discovery signals outside the time and/or frequency resources associated with the particular DMTC.

The apparatus <NUM>, and in particular the cellular baseband processor <NUM>, further includes means for transmitting, to a first UE, a set of DMTCs. The apparatus <NUM>, and in particular the cellular baseband processor <NUM>, further includes means for transmitting, to the first UE, information indicating a DMTC of the set of DMTCs to be used by the first UE for measuring discovery signals. The apparatus <NUM>, and in particular the cellular baseband processor <NUM>, further includes means for transmitting discovery signals to the first UE for the first UE to measure based on the indicated DMTC. As described supra, the apparatus <NUM> may include the TX Processor <NUM>, the RX Processor <NUM>, and the controller/processor <NUM>.

Referring again to <FIG>, a method and apparatus in association with adaptive DMTC for SL communications is provided. The adaptive DMTC allows the SL communication to use an appropriate amount of resources in a time-and-frequency resource space depending on changing conditions. For a first UE that establishes a PC5 interface with a second UE that relays communications from the first UE to a base station a first DMTC may be appropriate at a first time and at a second time a second DMTC may be appropriate. For example, if the first and second UEs are stationary relative to each other, a first DMTC with a first period between discovery signals may be appropriate, but if one of the UEs begins moving relative to the other a second, shorter, period associated with a second DMTC may be appropriate. Additionally, if each UE is configured with a plurality of (pre-configured) DMTCs signaling a switch from one DMTC in the set of DMTCs to another DMTC in the set of DMTCs is simplified by transmitting an identifier of the other DMTC instead of transmitting all the information necessary to define a DMTC.

Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean "one and only one" unless specifically so stated, but rather "one or more. " Terms such as "if," "when," and "while" should be interpreted to mean "under the condition that" rather than imply an immediate temporal relationship or reaction. That is, these phrases, e.g., "when," do not imply an immediate action in response to or during the occurrence of an action, but simply imply that if a condition is met then an action will occur, but without requiring a specific or immediate time constraint for the action to occur. Unless specifically stated otherwise, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof' include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof' may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. The words "module," "mechanism," "element," "device," and the like may not be a substitute for the word "means. " As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase "means for.

The following aspects are illustrative only and may be combined with other aspects or teachings described herein, without limitation.

Aspect <NUM> is a method of wireless communication of a first UE, including receiving, from a second UE, a set of DMTCs, receiving information indicating a DMTC of the set of DMTCs to be used for measuring discovery signals, and measuring discovery signals received from the second UE based on the indicated DMTC.

Aspect <NUM> is the method of aspect <NUM>, where the set of DMTCs is received through RRC signaling or system information.

Aspect <NUM> is the method of any of aspects <NUM> and <NUM>, where the information indicating the DMTC of the set of DMTCs to be used for measuring discovery signals is received through at least one of a MAC-CE, SCI, or PSFCH.

Aspect <NUM> is the method of any of aspects <NUM> to <NUM>, where one of the DMTCs in the set of DMTCs is a default DMTC for measuring discovery signals when the information indicating the DMTC of the set of DMTCs is not received.

Aspect <NUM> is the method of any of aspects <NUM> to <NUM>, where the DMTC includes at least a duration and a periodicity for measuring discovery signals.

Aspect <NUM> is the method of any of aspects <NUM> to <NUM>, further including receiving second information indicating that a first resource pool should be used for performing channel measurements on the discovery signals received from the second UE based on the indicated DMTC, wherein the channel measurements are performed based on the indicated DMTC within the resources of the first resource pool and communicating through at least one of a physical sidelink shared channel (PSSCH) or physical sidelink control channel (PSCCH) with the second UE through a second resource pool.

Aspect <NUM> is the method of any of aspects <NUM> to <NUM>, further including receiving second information indicating that a first carrier should be used for performing channel measurements on the discovery signals received from the second UE based on the indicated DMTC, wherein the channel measurements are performed based on the indicated DMTC within the first carrier and communicating through at least one of a physical sidelink shared channel (PSSCH) or physical sidelink control channel (P SCCH) with the second UE through a second carrier.

Aspect <NUM> is the method of any of aspects <NUM> to <NUM>, further including communicating through at least one of a physical sidelink shared channel (PSSCH) or physical sidelink control channel (PSCCH) with the second UE on an active bandwidth part (BWP), where the channel measurements performed on the discovery signals received from the second UE based on the indicated DMTC are performed outside the BWP and refraining from transmitting or receiving data communication with the second UE when performing the channel measurements on the discovery signals received from the second UE.

Aspect <NUM> is the method of any of aspects <NUM> to <NUM>, further including communicating through at least one of a physical sidelink shared channel (PSSCH) or physical sidelink control channel (PSCCH) with the second UE using a first numerology, wherein the channel measurements performed on the discovery signals received from the second UE based on the indicated DMTC use a second, different numerology and refraining, due to the different first and second numerologies, from transmitting or receiving communication with the second UE when performing the channel measurements on the discovery signals received from the second UE.

Aspect <NUM> is the method of <NUM>, further including determining whether UE mobility conditions are greater than a first UE mobility threshold or less than a second UE mobility threshold, wherein the DMTC recommendation is transmitted based on the determination.

Aspect <NUM> is a method of wireless communication of a second UE, including transmitting, to a first UE, a set of DMTCs, transmitting, to the first UE, information indicating a DMTC of the set of DMTCs to be used by the first UE for measuring discovery signals and transmitting discovery signals to the first UE for the first UE to measure based on the indicated DMTC.

Aspect <NUM> is the method of aspect <NUM>, where the set of DMTCs is transmitted through radio resource control (RRC) signaling or system information.

Aspect <NUM> is the method of any of aspects <NUM> and <NUM>, further including transmitting second information indicating at least one of a first resource pool, a first carrier, a first bandwidth part (BWP), or a first numerology through which the discovery signals are transmitted from the second UE for the first UE to measure based on the indicated DMTC and communicating through at least one of a physical sidelink shared channel (P SSCH) or physical sidelink control channel (P SCCH) with the first UE through at least one of a corresponding second resource pool, second carrier, second BWP, or second numerology.

Aspect <NUM> is the method of any of aspects <NUM> to <NUM>, further including receiving a DMTC recommendation associated with the indicated DMTC from the first UE, wherein the information indicating the DMTC of the set of DMTCs to be used for measuring discovery signals is transmitted in response to the received DMTC recommendation through one of a media access control (MAC) control element (CE) (MAC-CE) or sidelink control information (SCI).

Aspect <NUM> is an apparatus for wireless communication including at least one processor coupled to a memory and configured to implement a method as in any of aspects <NUM> to <NUM>.

Aspect <NUM> is an apparatus for wireless communication including means for implementing a method as in any of aspects <NUM> to <NUM>.

Claim 1:
A method (<NUM>) of wireless communication of a first user equipment, UE, comprising:
receiving (<NUM>), from a second UE, a set of discovery channel measurement time configurations, DMTCs;
receiving (<NUM>) information indicating a DMTC of the set of DMTCs to be used for measuring discovery signals; and
measuring (<NUM>) discovery signals received from the second UE based on the indicated DMTC.