On-demand pilot signal (ODPS) for paging synchronization

Abstract

This disclosure provides systems, methods, and apparatuses for an on-demand pilot signal (ODPS) for paging synchronization. A UE (110) can transmit a request (140) to a network entity (120) during an RRC idle or RRC inactive state. The request (140) can include an explicit ODPS request, clock drift information, one or more proposed parameters for the ODPS, or any combination thereof. The network entity transmits an ODPS configuration (150) to the UE to configure the ODPS. The ODPS configuration can indicate an ODPS pilot pattern, quantity of symbols, frequencies, or other information to inform the UE how to receive the ODPS. The network entity transmits the ODPS (170) during a time period preceding a paging indication or wake-up signal (WUS) (180). The UE achieves time and frequency synchronization using the ODPS before receiving the paging indication or WUS.

Description

ON-DEMAND PILOT SIGNAL (ODPS) FOR PAGING SYNCHRONIZATIONCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This PCT Application claims benefit of priority to U.S. Provisional Patent Application No. 63 / 590,541, filed October 16, 2023, entitled “ON-DEMAND PILOT SIGNAL (ODPS) FOR PAGING SYNCHRONIZATION,” and assigned to the assignee hereof, the disclosures of which are incorporated by reference.TECHNICAL FIELD

[0002] This disclosure relates generally to wireless communication and some aspects relate to power saving techniques using an on-demand pilot signal (ODPS) for paging synchronization.DESCRIPTION OF RELATED TECHNOLOGY

[0003] This background description is provided for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] In a wireless communication system, a network entity (such as a base station) and a user equipment (UE) can implement techniques to reduce power consumption. Several techniques seek to reduce the amount of time that a UE monitors a wireless channel. For example, a UE operates in a radio resource control (RRC) connected state when the UE has an active wireless connection with a network entity. In the RRC connected state, the UE maintains clock and frequency synchronization with the wireless channel based on the active communication between the UE and the network entity. During times when the UE does not have an active wireless connection with the network entity, the UE can enter a power saving mode. For example, the UE transitions from the RRC connected state to an RRC idle state or RRC inactive state. In the RRC idle state, the UE releases the RRC configuration. In theRRC inactive state, the UE suspends the RRC configuration and the RRC configuration can remain dormant until the UE transitions back to the RRC connected state.

[0005] The RRC idle state and the RRC inactive state can reduce power consumption because the UE only periodically wakes up its receiver components to monitor the wireless channel for a wake-up signal (WUS) or paging indications from the network entity. However, because there is limited communication between the network entity and the UE in the RRC idle state and RRC inactive state, the UE can experience clock drift that impacts its ability to properly receive transmissions from the network entity. Clock drift refers to a loss of synchronization with the wireless channel and can include time and / or frequency drift. A time drift refers to a loss of time synchronization. A frequency drift refers to a loss of frequency synchronization. Depending on the amount of clock drift since a previous synchronization procedure, the UE might not successfully receive a WUS or paging indication.BRIEF SUMMARY

[0006] The systems, methods, and apparatuses of this disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0007] One innovative aspect of the subject matter described in this disclosure can be implemented as a method by a user equipment (UE). The method includes requesting, from a network entity, an on-demand pilot signal (ODPS) while the UE is in a radio resource control (RRC) idle or inactive state. The method includes receiving an ODPS configuration from the network entity. The method includes receiving the ODPS from the network entity based on the ODPS configuration during a time period preceding a wake-up signal (WUS) or a paging indication from the network entity. The method includes acquiring time and frequency synchronization with the network entity based on the ODPS before receiving the WUS or the paging indication.

[0008] Another innovative aspect of the subject matter described in this disclosure can be implemented as a method by a network entity. The method includes configuring an ODPS in coordination with at least one UE while the at least one UE is in a RRC idle or inactive state. The method includes transmitting the ODPS to the at least one UE during a time periodpreceding a wake-up signal (WUS) or a paging indication from the network entity. The method also includes the network entity transmitting the WUS or the paging indication after transmitting the ODPS.

[0009] Another innovative aspect of the subject matter described in this disclosure can be implemented as an apparatus. The apparatus includes a communication unit and a processing system configured to control the communication unit to implement any of the abovereferenced methods. Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.

[0010] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Like reference numbers and designations in the various drawings indicate like elements. Note that the relative dimensions of the figures may not be drawn to scale. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

[0012] FIG. 1 shows an example wireless communication system and an implementation of an on-demand pilot signal (ODPS).

[0013] FIG. 2 shows an example communication flow diagram according to some aspects of this disclosure.

[0014] FIG. 3 shows example signaling from a UE and from a network entity according to some aspects of this disclosure.

[0015] FIG. 4 shows example signaling from a network entity to a UE according to some aspects of this disclosure.

[0016] FIG. 5 shows example ODPS pilot patterns according to aspects of this disclosure.

[0017] FIG. 6 shows an example ODPS request and configuration using a Type-1 random access procedure according to aspects of this disclosure.

[0018] FIG. 7 shows another example ODPS request and configuration using a Type-1 random access procedure according to aspects of this disclosure.

[0019] FIG. 8 shows an example ODPS request and configuration using a Type-2 (two-step) random access procedure according to aspects of this disclosure.

[0020] FIG. 9 shows an example implementation in which a network entity configures multiple UEs with a common ODPS configuration.

[0021] FIG. 10 shows example operations of a UE according to aspects of this disclosure.

[0022] FIG. 11 shows example operations of a network entity according to aspects of this disclosure.

[0023] FIG. 12 shows a block diagram of an example user equipment (UE) and an example network entity.DETAILED DESCRIPTION

[0024] The following description is directed to certain implementations for the purpose of describing innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. Some of the examples in this disclosure are based on wireless communication according to the 3rd Generation Partnership Project (3GPP) wireless standards, such as the 4th generation (4G) Long Term Evolution (LTE) and 5th generation (5G) New Radio (NR) standards. However, the described implementations can be implemented in any device, system, or network that is capable of transmitting and receiving radio frequency signals according to any of the wireless communication standards, including any of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 or 802.16 wireless standards, or other known signals that are used to communicate within a wireless, cellular, or internet of things (1OT) network, such as a system utilizing 4G, 5G, WiFi or future radio technology.

[0025] Aspects of this disclosure relate to clock drift. Clock drift refers to a loss of synchronization with the wireless channel and can include time drift and / or frequency drift. Some references to clock drift in this disclosure collectively refer to either or both of time drift or frequency drift. Several factors can impact the clock drift rate at a user equipment (UE), such as ambient temperature, processor temperature, available power, UE circuit design, or component aging, among other examples. Depending on the amount ofclock drift since a previous synchronization procedure, the UE might miss a paging indication or wake-up signal (WUS). Traditional mechanisms for correcting clock drift include the UE monitoring periodic reference signals from the network entity to maintain synchronization. Monitoring the periodic reference signals consumes power or requires the UE to monitor the wireless channel for a longer period of time prior to receiving a paging channel signal. In some instances, a UE operates in a radio resource control (RRC) idle state and RRC inactive state, in which there is limited communication between the network entity and the UE. Furthermore, some reference signals (such as a cell-specific reference signal (CRS)) can be omitted in some wireless communication systems. For example, the 3GPP technical specifications for 5th generation new radio (5G NR) omit the CRS that was previously broadcast by a network entity of earlier generation wireless technologies. Instead of the CRS, 5G NR uses a synchronization signal block (SSB) which occurs less frequently and would require additional time for a UE to achieve clock synchronization.

[0026] This disclosure provides systems, methods, and apparatuses for an on-demand pilot signal (ODPS) for paging synchronization. The ODPS can include a set of pilot signals that a network entity transmits during a time period preceding a paging indication or WUS. A UE can receive the ODPS to quickly achieve time and frequency synchronization before the WUS or the paging indication. In accordance with aspects of this disclosure, the UE can transmit signaling, during an RRC idle or RRC inactive state, to the network entity to request the ODPS. For example, the signaling can indicate a clock drift rate or can indicate how many ODPS pilot symbols are needed by the UE to synchronize to the wireless channel. In some implementations, the clock drift information is calibrated (such as during manufacturing or testing) to determine clock drift rates corresponding to various temperatures. The UE can measure the ambient temperature and report the clock drift rate to the network entity so that the network entity can select an ODPS configuration that enables the UE to synchronize to the wireless channel before the WUS or paging indication.

[0027] The disclosure includes several options for a UE to explicitly or implicitly request an ODPS configuration. In some implementations, the UE communicates its clock drift information, requests an ODPS configuration, or possibly indicates a preferred ODPS pilot pattern, among other examples. In some implementations, the requested ODPS pilot pattern is based, at least in part, on a time drift rate or frequency drift rate of the UE. The UE cancommunicate control signaling related to the ODPS while the UE is in an RRC idle or RRC inactive state. For example, the UE can use a random access procedure to occasionally (or as needed) provide updated clock drift information to the network entity. In some aspects, the UE transmits signaling related to the ODPS via a random access preamble transmission (MSG1) on a physical random access channel (PRACH), a random access request transmission (MSG3) on a physical uplink shared channel (PUSCH) following a contention based random access, or a random access message A (MSGA) that includes both the random access preamble and random access request. In some aspects, the UE includes control signaling related to the ODPS in a UE assistance information (UAI) message as part of or following a random access procedure with the network entity.

[0028] The network entity communicates an ODPS configuration to the UE. For example, the ODPS configuration can indicate timing for an ODPS that will be transmitted before the WUS or paging indication. Alternatively, or additionally, the ODPS configuration can indicate a quantity of symbols for the ODPS, a quantity of subbands for the ODPS, or an ODPS pilot pattern indicating the sequence or signature of the ODPS. The quantity of symbols for the ODPS can be adjusted based on the time drift rate, where the ODPS can include more symbols (and thus longer period of time) when a time drift rate is higher and the ODPS can include fewer symbols when the time drift rate is lower. Similarly, the quantity of subbands for the ODPS can be adjusted based on the frequency drift rate. The network entity can communicate the ODPS configuration via a random access response transmission (MSG2) in response to the MSG1, a contention resolution transmission (MSG4) in response to the MSG3, or a random access message B (MSGB) in response to the MSGA, where MSGB including both the random access response and the ODPS configuration.

[0029] In some aspects, the ODPS configuration can be coordinated based on an idle mode discontinuous reception (DRX) cycle of the UE or a cell discontinuous transmission (c-DTX) of the network entity. Discontinuous transmission (DTX) and discontinuous reception (DRX) refer to features of a wireless communication system to reduce power consumption by alternating between periods of sleep (off) and awake (on) radio transceiver statuses. As mentioned previously, UE clock drift tends to occur while a radio transceiver is asleep (off). After configuring DRX in a UE, the UE can periodically activate and deactivate its radio to monitor the radio frequency communications according to the DRX configuration. Typically,paging occasions for a UE is based on the DRX configuration of the UE. Tn accordance with aspects of this disclosure, the UE can concurrently request a DRX configuration and request the ODPS so that the network entity transmits the ODPS within an awake period of the DRX configuration.

[0030] In some aspects, the network entity can configure a common ODPS configuration for multiple UEs. In some implementations, the network entity receives clock drift information from multiple UEs and then groups UEs for paging by similar drift rates. Alternatively or additionally, the network entity can receive ODPS requests from multiple UEs and select a common ODPS configuration that satisfies multiple ODPS requests.

[0031] Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. A UE can request the network entity to send an ODPS during a time period just prior to a paging indication or WUS. This enables the UE to reduce power consumption during the RRC idle or inactive state because the UE can refrain from clock synchronization until the time period for the ODPS. The UE can quickly acquire time and synchronization with the network entity using the ODPS just prior to the paging indication or WUS. Periodic clock synchronization using a SSB might take longer compared to clock synchronization using the ODPS. Therefore, the ODPS can further reduce power consumption by the UE. Because the ODPS configuration is based on the clock drift rate of the UE, the ODPS can include a sufficient quantity and pattern of ODPS pilot signals that will enable clock synchronization while potentially reducing the time or frequency resources that would be included in a non-UE-specific clock synchronization signal. In some aspects, the UE proposes parameters for the ODPS configuration, which enable the network entity to establish the ODPS configuration effectively for the UE or for a group of UEs.

[0032] FIG. 1 shows an example wireless communication system 100 and an implementation of an ODPS 170. The wireless communication system 100 includes a network entity 120 and an example UE 110. Although illustrated as a smartphones in FIG. 1, the UE 110 can be implemented as any suitable computing or electronic device, such as a mobile communication device, a modem, cellular phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, smart appliance, vehicle-based communication system, an Internet-of-things (IoT) device (e.g., sensor node,control ler / actuator node, combination thereof), and the like. The network entity 120 supports wireless communication with one or more UEs via radio frequency (RF) signaling using one or more applicable radio access technologies (RATs) as specified by one or more communications protocols or standards. The network entity 120 may employ any of a variety of RATs, such as operating as a NodeB (or base transceiver station (BTS)) for a Universal Mobile Telecommunications System (UMTS) RAT (also known as “3G”), operating as an enhanced NodeB (“eNB”) for a Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) RAT, operating as a 5G node B (“gNB”) for a 3GPP Fifth Generation New Radio (5G NR) RAT, and the like. The network entity 120 (e.g., base station, an Evolved Universal Terrestrial Radio Access Network Node B (E-UTRAN Node B), evolved Node B, eNodeB, eNB, Next Generation Node B, gNode B, gNB, ng-eNB, access point, radio head or the like), may be implemented in a macrocell, microcell, small cell, picocell, or the like, or any combination thereof. In some aspects, the functionality, and thus the hardware components, of the network entity 120 may be distributed across multiple network nodes or devices and may be distributed in a manner to perform the functions described herein. As one example, the functionality of the network entity 120 may be distributed across a radio unit (RU), distributed unit (DU), or central unit (CU).

[0033] The network entity 120 and the UE 110 communicate using wireless links. The wireless links can include one or more wireless links (e.g., radio links) or bearers implemented using any suitable communication protocol or standard, or combination of communication protocols or standards, such as 3GPP LTE, 5G NR, and so forth. In some implementations, multiple wireless links are aggregated in a carrier aggregation to provide a higher data rate for the UE 110. The network entity 120 may be part of a radio access network (RAN), for example, an Evolved Universal Terrestrial Radio Access Network, E-UTRAN, 5G NR RAN, or NR RAN. The network entity 120 may be connected to a core network (not shown) that provides access to services or other networks. The network entity 120 and the UE 110 may be configured to use multiple-user multiple-input multiple-output (MU-MIMO) communication in which the network entity 120 can transmit multiple downlink transmissions using beam forming and orthogonal frequency division multiplexing (OFDM).

[0034] The network entity 120 and the UE 110 utilize an uplink (UL) transmission path for RF transmissions (referred to as uplink transmissions) from the UE 110 to the network entity120, and a downlink (DL) transmission path for RF transmissions (referred to as downlink transmissions) from the network entity 120 to the UE 110. The UL transmission path may include a Physical Uplink Shared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH), and a Physical Random Access Channel (PRACH). The PUSCH is used for the transmission of user data, such as voice data, video data, or text message data from the UE 110 to network entity 120. Additionally, the PUSCH may be used to transmit control information (e.g., uplink control information (UCI). The PUSCH may be shared by multiple UEs. The PUCCH is used for transmitting control information (e.g., UCI) from the UE to the network, such as channel quality feedback, scheduling requests, and acknowledgments. The PRACH is used for random access in the uplink direction, enabling the UE 110 to access the system without a prior reservation. The DL transmission path may include one or more of a Physical Downlink Shared Channel (PDSCH), a Physical Downlink Control Channel (PDCCH), a Physical Broadcast Channel (PBCH), or a paging channel. The PDSCH is used for transmission of user data from the network entity 120 to the UE 110. The PDSCH may be shared by multiple UEs. As with the PUSCH, PDSCH data may be any type of information, such as voice data, video data, or text message data. The paging channel is used to notify the UE 110 that there is incoming traffic for it from the network entity 120.

[0035] Radio resource control (RRC) is a component of a radio interface protocol stack that the network entity 120 and the UE 110 use to communicate. Among other functions, the network entity 120 and the UE 110 use RRC messaging to establish and / or release radio connections and resources. In an RRC connected state, the UE 110 has an active wireless radio connection with a network entity 120. When an active wireless radio connection is not needed, the UE 110 can transition from the RRC connected state to an RRC idle or inactive state to release or suspend, respectively, the wireless radio connection. As described previously, the UE 110 may experience clock drift during the RRC idle or inactive state. Unless the UE 110 synchronizes with the wireless channel, and depending on the amount of clock drift since a previous synchronization procedure, the UE 110 might not successfully receive a paging indication or WUS 180.

[0036] In accordance with aspects of this disclosure, the UE 1 10 and the network entity 120 can set up (block 130) an ODPS during the RRC idle or inactive state. The UE 110 transmits a request 140 for the ODPS 170. The request 140 can be an implicit request for the ODPS170, such as by sending clock drift information indicating the clock drift rate of the UE 1 10. Alternatively, or additionally, the request 140 can include an explicit request for the ODPS 170, such as a request indication or by including a proposed parameter for the ODPS 170. For example, the proposed parameter can include a proposed quantity of symbols for the ODPS 170, a proposed quantity of subbands for the ODPS 170, a proposed ODPS pilot pattern, or any combination of these parameters.

[0037] The network entity 120 transmits, and the UE 110 receives, an ODPS configuration 150 from the network entity 120. The ODPS configuration can indicate the quantity of symbols for the ODPS 170, a quantity of subbands for the ODPS 170, or an ODPS pilot pattern indicating a sequence or signature of the ODPS 170, among other examples. The UE 110 can implement the ODPS configuration 150 in its receiver so that the receiver can achieve clock synchronization using the ODPS 170 during a time period before a window for the paging indication or WUS 180. Shown at block 160, the network entity 120 transmits the ODPS 170 before the paging indication or WUS 180.

[0038] FIG. 2 shows an example communication flow diagram 200 according to some aspects of this disclosure. The communication flow diagram 200 shows the communication between the network entity 120 and the UE 110. In some implementations, a UE 110 sends a message 203 to the network entity 120 that indicates the UE 110 supports ODPS. The message 203 can be a UAI message, a UE capability message, an ODPS request message, or any type of message that informs the network entity 120 that the UE 110 supports ODPS for synchronization before paging indication or WUS. At some point, when the UE 110 is in an RRC connected state 201, the network entity 120 sends an RRC Release or RRC Suspend Command 205. An RRC Release command releases radio resources as part of a transition to the RRC idle state. An RRC Suspend command suspends the radio resources as part of a transition to the RRC inactive state. Based on the RRC Release or RRC Suspend Command 205, the UE 110 enters the RRC idle / inactive state 207.

[0039] In the communication flow diagram 200, the ODPS is set up 230 during the RRC idle / inactive state 207. The UE 110 sends a request 240 to the network entity 120 for an ODPS configuration. In some implementations, the request 240 is an implicit request. For example, the request 240 can be any message that causes the network entity 120 to prepare an ODPS configuration for the UE 110. The request 240 can include clock drift information,such as a clock drift rate, indication of loss of clock synchronization, movement of the UE, or other information that the network entity 120 can infer to represent a request for the ODPS configuration. In some implementations, the request 240 includes an explicit request such as an ODPS request or a proposed parameter for the ODPS configuration. As described further with reference to FIG. 6 through FIG. 8, the UE 110 can include the request 240 in a MSG1, MSG3, or MSGA as part of a random access procedure during the RRC idle / inactive state 207. Although FIG. 2 shows the request 240 being sent during the RRC idle / inactive state 207, In some implementations, the UE 110 can transmit part or all of the request for ODPS during the RRC connected state 201 (such as via a message 203).

[0040] The network entity 120 transmits the ODPS configuration 250 to the UE 110 in response to the request 240. In some implementations, the ODPS configuration 250 is specific to the UE 110 and is based on clock drift information or a proposed parameter in the request 240. As described further with reference to FIG. 6 through FIG. 8, the network entity 120 can include the ODPS configuration 250 in a MSG2 (in response to an MSG1), a MSG4 (in response to an MSG3), or a MSGB (in response to an MSGA) as part of the random access procedure.

[0041] After setting up 230 the ODPS, the network entity 120 transmits (260) the ODPS and paging. The ODPS 270 is sent during a time period preceding the paging indication or WUS 280. In some implementations, the ODPS 270 immediately precedes the paging indication or WUS 280. The UE 110 uses the ODPS 270 to achieve time and frequency synchronization with the wireless channel before receiving the paging indication or WUS 280.

[0042] FIG. 3 shows example signaling 340 from a UE 110 and from a network entity 120 according to some aspects of this disclosure. The example signaling 340 includes examples of an implicit or explicit request for the ODPS (such as the requests 140 and 240 described with reference to FIG. 1 and FIG. 2, respectively). The example signaling 340 can include an explicit request for ODPS configuration 342, clock drift information 344, and / or a proposed parameter 346 for the ODPS. Examples of clock drift information 344 include clock drift rate and / or a time drift rate. For example, the proposed parameter 346 can indicate a proposed ODPS pilot pattern, proposed ODPS configuration elements (e.g., quantity of symbols and / or quantity of subbands), and / or a quantity of pilots. In some implementations, the example signaling 340 also indicates a requested discontinuous reception (DRX) cycle 348 of the UE1 10. When preparing the ODPS configuration, the network entity 120 can avoid time periods when the UE 110 is offline according to the DRX cycle 348.

[0043] FIG. 4 shows example signaling 450 from a network entity 120 to a UE 110 according to some aspects of this disclosure. The network entity 120 can transmit the example signaling 450 to the UE 110 to indicate an ODPS configuration 451. In some implementations, the network entity 120 also transmits a DRX configuration 458 with the ODPS configuration 451. The ODPS configuration 451 can indicate a time duration 452 (such as a time value, a quantity of symbols, or transmission time intervals (TTIs), among other examples), one or more frequencies 453 (such as a quantity of subbands, a set of frequencies, or resource sets, among other examples), or an ODPS pilot pattern 454, among other examples. The ODPS configuration 451 can include any information that enables the UE 110 to receive ODPS pilots within time and frequency resources of one or more OFDM symbols.

[0044] FIG. 5 shows example ODPS pilot patterns according to aspects of this disclosure. Depending on the clock drift rate of a particular UE 110, a network entity 120 can adjust the quantity of ODPS pilots. For example, the network entity 120 can configure more symbols with ODPS pilots for a UE 110 experiencing more time drift, and can configure fewer symbols with ODPS pilots for a UE 110 experiencing less time drift. Similarly, the network entity 120 can configure more symbols with ODPS pilots for a UE experiencing more time drift, and can configure fewer symbols with ODPS pilots for a UE experiencing less time drift. The shading in FIG. 5 represents the locations of ODPS pilots for three example ODPSs 570A, 570B, and 570C. An ODPS can include any quantity of ODPS pilots. Although the example ODPSs 570A, 570B, 570C shown in FIG. 5 illustrate the ODPS pilots occupying consecutive subcarriers and consecutive symbols, other ODPS configurations are possible. The network entity 120 can configure ODPS pilots that are located in non-consecutive subcarriers, non- consecutive symbols, or both.

[0045] An ODPS pilot pattern refers to the locations of the ODPS pilots occupying particular subcarriers among a plurality of OFDM symbols. Each ODPS pilot can have different values, and an ODPS sequence refers to the values that populate the various ODPS pilots. In some implementations, the ODPS pilot pattern and / or ODPS sequence is specified in a technical specification. Alternatively, or additionally, a technical specification can indicate several options for the ODPS pilot pattern and a corresponding ODPS sequence. The several optionsmay be associated with corresponding index values in a lookup table. In some implementations, a UE can transmit a proposed parameter for the ODPS, where the proposed parameter is an index value referring to one of the predefined options in the lookup table. Similarly, a network entity 120 can refer to a predefined option by including an index value in an ODPS configuration. Using a lookup table with predefined options provides a potential technical advantage of reducing communication overhead. In some implementations, the ODPS pilot pattern and / or ODPS sequence can be customized or fully configured in an ODPS request message or ODPS configuration message. Using a bespoke ODPS pilot pattern and / or ODPS sequence provides a potential technical advantage of configuring an ODPS that is not limited to predefined options and that can be optimized for a particular UE or group of UEs.

[0046] The example ODPSs 570A, 570B, and 570C are provided to illustrate how an ODPS pilot pattern is proposed or configured based on different clock drift scenarios. Clock drift can include a time drift, a frequency drift, or both. When a UE 110 provides clock drift information, it can indicate a clock drift rate, such a rate of drift in time or frequency synchronization. A higher drift rate (in time or frequency or both) might require a larger number of ODPS pilots compared to a lower drift rate.

[0047] A UE experiencing a higher rate of time drift may benefit from an ODPS pattern that includes more symbols (e.g., more synchronization time) compared to a UE experiencing a lower rate a time drift. A first example ODPS 570A includes four ODPS pilots 572A that are located on two subcarriers of a first OFDM symbol and a second OFDM symbol. The second example ODPS 570B includes eight ODPS pilots 572B that are located on two subcarriers in each of four OFDM symbols. The first example ODPS 570A might be suitable for a UE with a lower rate of time drift, while the second example ODPS 570B might be more suitable for a UE with a higher rate of time drift.

[0048] A UE experiencing a higher rate of frequency drift may benefit from an ODPS pattern that includes more subcarriers (e.g., more frequencies to achieve frequency synchronization) compared to a UE experiencing a lower rate of frequency drift. A third example ODPS 570C includes eight ODPS pilots 572C that are located on four subcarriers of a first OFDM symbol and a second OFDM symbol. The first example ODPS 570A might be suitable for a UE witha lower rate of frequency drift, while the third example ODPS 570C might be more suitable for a UE with a higher rate of frequency drift.

[0049] The examples in FIG. 5 are provided for pedagogical purposes to explain how a UE 110 or a network entity 120 might take into account the time drift and frequency drift when setting up an ODPS. The UE 110 can use clock drift information or current conditions (e.g., component temperature, power, and / or age) of the UE 110 to propose an ODPS pilot pattern. Alternatively, or additionally, the UE 110 can provide clock drift information to the network entity, and the network entity 120 can configure the ODPS pilot pattern to account for the UE's rate(s) of time drift and / or frequency drift. FIG. 5 illustrates non-limiting examples of varying the quantities of ODPS pilots, subcarriers, and symbols based on different clock drift rates and type of drift.

[0050] FIG. 6 shows an example ODPS request and configuration using a Type-1 random access procedure according to aspects of this disclosure. A timing diagram 600 illustrates network entity communication 620 of a network entity (such as the network entity 120 described herein). The timing diagram 600 also illustrates UE communication 610 of a UE (such as the UE 110 described herein). The example UE communication 610 and network entity communication 620 can occur during an RRC idle or inactive state 607.

[0051] A random access procedure may be referred to as a random access channel (RACH) procedure. A Type-1 random access procedure also may be referred to as a 4-step RACH. The Type-1 random access procedure includes a protocol of up to four messages (referred to as MSG1, MSG2, MSG3, and MSG4). To begin the Type-1 random access procedure, a UE transmits a random access preamble in a first message (MSG1 642) via a PRACH. The network entity responds to the MSG1 642 by transmitting a second message (MSG2 652) via a PDSCH. The MSG2 652 is also referred to as a random access response (RAR) transmission. In some instances, the MSG2 652 indicates scheduled resources (in a PUSCH) for the UE to use for transmission of a third message (MSG3). When applicable, the UE transmits the MSG3 644 via the PUSCH resources granted by the network entity. In response to the MSG3 644, the network entity transmits a fourth message (MSG4 654). The MSG4 654 is also referred to as a contention resolution transmission (MSG4). It is noted that the MSG3 644 and the MSG4 654 might not be needed. For example, the UE can include a small data transmission with the random access preamble in the MSG1 642 and the network entitycan include a response in the MSG2 652 without providing a grant for uplink resources for the MSG3 644.

[0052] In accordance with aspects of this disclosure (shown at block 640), the UE can include an ODPS request following the random access preamble in the MSG1 642. The ODPS request can include an explicit or implicit request for the ODPS configuration. In some implementations, the MSG1 642 can include clock drift information or a proposed parameter for the ODPS, among other examples. The network entity can include the ODPS configuration 650 in the MSG2 652. A potential technical advantage of the protocol shown in FIG. 6 is that the MSG3 644 and the MSG4 654 might be omitted, reducing power consumption and communication overhead.

[0053] In an alternative aspect described with reference to FIG. 6, the UE can transmit the ODPS request in the MSG3 644. The network entity can transmit the ODPS configuration 650 in the MSG4 654. A potential technical advantage of using the MSG3 644 and the MSG4 654 for the ODPS request and ODPS configuration, respectively, is that those message types can include a larger amount of data compared to the MSG1 642 and the MSG2 652. Therefore, the ODPS request can include more information to enable the network entity to prepare an ODPS configuration and the network entity can provide more information with the ODPS configuration.

[0054] After the ODPS configuration 650 has been sent to the UE (via either the MSG2 652 or the MSG4 654), the UE can implement the ODPS configuration 650 in its receiver. At a later time 660, the network entity transmits the ODPS 670 and the paging or WUS (via the PDCCH 680). The UE achieves time and frequency synchronization using the ODPS 670 before processing the PDCCH 680.

[0055] FIG. 7 shows another example ODPS request and configuration using a Type-1 random access procedure according to aspects of this disclosure. The features of FIG. 7 are the same as described with reference to FIG. 6. In FIG. 7, the UE transmits the ODPS request via the MSG3 644 and the network entity transmits the ODPS configuration 650 via the MSG4 654. In some implementations, the UE transmits the ODPS request in a UE assistance information (UAI) message 740. A UAI message is typically transmitted during an RRC connected state. However, in accordance with aspects of this disclosure, a UE can include a UAI message in a RACH message during the RRC idle or inactive state. The UAI messagecan be extended to include the ODPS request (such as clock drift information, explicit ODPS request, and / or a proposed parameter, among other examples). In some other implementations not shown in Fig. 7, the UE can transmit an ODPS request in a UAI during RRC connected state (not shown).

[0056] FIG. 8 shows an example ODPS request and configuration using a Type-2 (two-step) random access procedure according to aspects of this disclosure. A Type-2 random access procedure can also be referred to as a 2-step RACH. The 2-step RACH is a newer protocol for random access compared to the 4-step RACH. In the 2-step RACH, the UE can transmit the random access preamble followed by a PUSCH in the first message (referred to as MSGA 840). The network entity responds to the MSGA 840 by transmitting a second message (MSGB 850) via a PDSCH. One way to describe the 2-step RACH is that the MSGA is a combination of the MSG1 and MSG3 in a first transmission and the MSGB is a combination of the MSG2 and MSG4 in a second transmission.

[0057] In accordance with aspects of this disclosure, the UE can include the ODPS request (block 640) in the MSGA 840. The network entity can transmit the ODPS configuration 650 via the MSGB 850. Some potential technical advantages of the 2-step RACH are that the 2- step RACH can reduce the number of signaling steps, reduce communication overhead, reduce protocol latency, and reduce power consumption.

[0058] FIG. 9 shows an example implementation in which a network entity 120 configures multiple UEs with a common ODPS configuration. An example wireless communication system 900 includes a network entity 120 and several example UEs (UEs 110, 912, 914, and 916). The wireless communication system 900 is similar to the wireless communication system 100 described with reference to FIG. 1. FIG. 9 shows two types of ODPS configurations that can be used in a wireless communication system.

[0059] In some aspects, the network entity 120 can provide a common ODPS configuration 951 to multiple UEs (such as UEs 912, 914, and 916). In some implementations, the network entity 120 can receive clock drift information from multiple UEs. The network entity 120 can group several UEs for a common ODPS configuration 951 and paging based on the UEs that have similar clock drift rates. In the example of FIG. 9, UEs 912, 914, and 916 have similar clock drift rates and can use the same ODPS (shown as first ODPS 971) for time and frequency synchronization before a paging or WUS window. Alternatively, or additionally, the networkentity can receive ODPS requests from multiple UEs and select a common ODPS configuration that satisfies multiple ODPS requests. A common ODPS configuration can provide a potential technical advantage of reducing communication overhead and efficiently grouping UEs that have similar synchronization and paging requirements.

[0060] In some aspects, the network entity 120 can provide a unique ODPS configuration 952 for a particular UE (such as UE 110). The network can transmit an ODPS (shown as a second ODPS 972) that is specific to the UE 110. A UE-specific ODPS configuration can provide a potential technical advantage of improving synchronization opportunities for a particular UE that has a clock drift rate different from other UEs in the coverage area of the network entity 120.

[0061] FIG. 10 shows example operations 1000 of a UE (such as the UE 110 described herein) according to aspects of this disclosure. At block 1040, the UE (110) transmits, to a network entity (120), a request (140) for an ODPS while the UE (110) is in a RRC idle or inactive state. At block 1050, the UE receives an ODPS configuration (150) from the network entity. At block 1070, the UE receives the ODPS (170) from the network entity (120) based on the ODPS configuration during a time period preceding a WUS or a paging indication (180) from the network entity. At block 1080, the UE acquires time and frequency synchronization with the network entity (120) based on the ODPS (170) before receiving the WUS or the paging indication (180).

[0062] FIG. 11 shows example operations 1100 of a network entity (such as the network entity 120 described herein) according to aspects of this disclosure. At block 1140, the network entity receives, from at least one UE (110), a request (140) for an ODPS while the at least one UE (110) is in a RRC idle or inactive state. At block 1150, the network entity transmits an ODPS configuration (150) to the at least one UE (110). At block 1170, the network entity transmits the ODPS (170) during a time period preceding a WUS or a paging indication (180) from the network entity (120) to the at least one UE (110). At block 1180, the network entity transmits the WUS or the paging indication (180) after the ODPS (170).

[0063] FIG. 12 shows a block diagram of an example UE 1210 and an example network entity 1220. Note that the depicted hardware configurations represent the processing components and communication components of a network entity 1220 (such as the network entity 120 described herein) and a UE 1210 (such as the UE 110 described herein). Thedepicted hardware configurations may omit certain components well -understood to be frequently implemented in such electronic devices, such as displays, peripherals, power supplies, and the like.

[0064] The UE 1210 includes antennas 1211, a radio frequency front end (RF front end) 1212, and radio-frequency transceivers (e.g., an LTE transceiver 1214 and a 5G NR transceiver 1213) for communicating with the network entity 1220. The RF front end 1212 includes one or more modems configured for the corresponding RAT(s) employed (for example, Third Generation Partnership Project (3GPP) Fifth Generation New Radio (5G NR)), one or more analog-to-digital converters (ADCs), one or more digital-to-analog converters (DACs), signal processors, and the like. In the example illustrated in FIG. 12, the RF front end 1212 of the UE 1210 may couple or connect the 5G NR transceiver 1213 to the antennas 1211 to facilitate various types of wireless communication. The RF front end 1212 operates, in effect, as a physical (PHY) transceiver interface to conduct and process signaling between the one or more processor(s) 1215 and antennas 1211 so as to facilitate various types of wireless communication.

[0065] The antennas 1211 of the UE 1210 include an array of multiple antennas that may be tuned to one or more frequency bands associated with a corresponding RAT. The antennas 1211 and the RF front end 1212 are tuned to, and / or be tunable to, one or more frequency bands defined by the 3GPP 5G NR communication standards and implemented by the 5G NR transceiver 1213. Additionally, the antennas 1211, the RF front end 1212, and / or the 5G NR transceiver 1213 can be configured to support beamforming for the transmission and reception of communications with the network entity 1220. By way of example and not limitation, the antennas 1211 and the RF front end 1212 may be implemented for operation in sub-gigahertz bands, sub-6 GHz bands, and / or above 6 GHz bands that are defined by the 3GPP LTE and 5G NR communication standards.

[0066] The UE 1210 also includes processor(s) 1215 and computer-readable storage media (CRM) 1216. The processor(s) 1215 may include, for example, one or more central processing units, graphics processing units (GPUs), or other application-specific integrated circuits (ASIC), and the like. To illustrate, the processor(s) 1215 may include an application processor (AP) utilized by the UE 1210 to execute an operating system and various user-level software applications, as well as one or more processors utilized by modems or a baseband processorof the RF front end 1212. The CRM 1216 may include any suitable memory or storage device such as random-access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), nonvolatile RAM (NVRAM), read-only memory (ROM), Flash memory, solid-state drive (SSD) or other mass-storage devices, and the like useable to store one or more sets of executable software instructions and associated data that manipulate the one or more processor(s) 1215 and other components of the UE 1210 to perform the various functions described herein and attributed to the UE 1210. The sets of executable software instructions include, for example, an operating system (OS) and various drivers (not shown), and various software applications (not shown), which are executable by processor(s) 1215 to enable user-plane communication, control-plane signaling, and user interaction with the UE 1210.

[0067] Turning to the hardware of the network entity 1220, it is noted that although FIG. 12 illustrates an implementation of the network entity 1220 as a single network node (for example, a 5G NR Node B, or “gNB”), the functionality, and thus the hardware components, of the network entity 1220 instead may be distributed across multiple network nodes or devices and may be distributed in a manner to perform the functions described herein. As one example, the functionality of network entity 1220 may be distributed across a radio unit (RU), distributed unit (DU), or central unit (CU).

[0068] The network entity 1220 includes antennas 1221, a radio frequency front end (RF front end) 1222, and one or more 5G NR transceivers 1223 for communicating with the UE 1210. The RF front end 1222 of the network entity 1220 may couple or connect the 5G NR transceivers 1223 to the antennas 1221 to facilitate various types of wireless communication. Similar to RF front end 1212, the RF front end 1222 includes one or more modems, one or more ADCs, one or more DACs, and the like. RF front end 1222 receives the one or more RF signals, for example, RF signals from UE 1210, and pre-processes the one or more RF signals to generate data from the RF signals that is provided as input to processes and / or applications executing on network entity 1220. This pre-processing may include, for example, power amplification, conversion of band-pass signaling to baseband signaling, initial analog-to-digital conversion, and the like.

[0069] The antennas 1221 of the network entity 1220 may be configured individually and / or as one or more arrays of multiple antennas. The antennas 1221 and the RF front end 1222 may be tuned to, and / or be tunable to, one or more frequency band defined by the 3GPP 5GNR communication standards, and implemented by the 5G NR transceivers 1223. Additionally, the antennas 1221, the RF front end 1222, and the 5G NR transceivers 1223 may be configured to support beamforming, such as Massive-MIMO, for the transmission and reception of communications with the UE 1210.

[0070] The network entity 1220 also includes processor(s) 1225 and computer-readable storage media (CRM) 1226. The processor(s) 1225 may include, for example, one or more central processing units, graphics processing units (GPUs), or other application-specific integrated circuits (ASIC), and the like. To illustrate, the processor(s) 1225 may include an application processor (AP) utilized by the network entity 1220 to execute an operating system and various user-level software applications, as well as one or more processors utilized by modems or a baseband processor of the RF front end 1222 to enable communication with the UE 1210.

[0071] FIG. 1 through FIG. 12 and the operations described herein are examples meant to aid in understanding example implementations and should not be used to limit the potential implementations or limit the scope of the claims. Some implementations may perform additional operations, fewer operations, operations in parallel or in a different order, and some operations differently.

[0072] The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects. While the aspects of the disclosure have been described in terms of various examples, any combination of aspects from any of the examples is also within the scope of the disclosure. Alternatively, or in addition to the other examples described herein, examples include any combination of the following implementation options (identified as clauses for reference).

[0073] Clauses

[0074] Clause 1. A method by a user equipment (UE) (110), including: transmitting, to a network entity (120), a request (140) for an on-demand pilot signal (ODPS) while the UE (1 10) is in a radio resource control (RRC) idle or inactive state; receiving an ODPS configuration (150) from the network entity; receiving the ODPS (170) from the networkentity (1 0) based on the ODPS configuration during a time period preceding a wake-up signal (WUS) or a paging indication (180) from the network entity; and acquiring time and frequency synchronization with the network entity (120) based on the ODPS (170) before receiving the WUS or the paging indication (180).

[0075] Clause 2. The method of clause 1, where the transmitting the request includes transmitting at least one of: a request for the ODPS configuration, clock drift information, or a proposed parameter for the ODPS configuration.

[0076] Clause 3. The method of clause 2, where the proposed parameter for the ODPS configuration includes at least one of: a quantity of symbols for the ODPS, a quantity of subbands for the ODPS, or an ODPS pilot pattern indicating a sequence or signature of the ODPS.

[0077] Clause 4. The method of clause 2 or 3, where the proposed parameter is based, at least in part, on a clock drift rate of the UE.

[0078] Clause 5. The method of any one of clauses 1 to 4, further including: transmitting, to the network entity, a communication indicating a discontinuous reception (DRX) cycle of the UE; and where the receiving the ODPS from the network entity is also based on the DRX cycle.

[0079] Clause 6. The method of any one of clauses 1 to 5, where the transmitting the request includes transmitting the request via at least one of: a random access preamble transmission (MSG1) on a physical random access channel (PRACH), a random access request transmission (MSG3) on a physical uplink shared channel (PUSCH) following a contention based random access, or a random access message A (MSGA) that includes both the random access preamble and random access request.

[0080] Clause 7. The method of clause 6, where the receiving the ODPS configuration from the network entity includes receiving the ODPS configuration via at least one of: a random access response transmission (MSG2) in response to the MSG1, a contention resolution transmission (MSG4) in response to the MSG3, or a random access message B (MSGB) in response to the MSGA.

[0081] Clause 8. The method of any one of clauses 1 to 7, where the transmitting the request includes transmitting a UE assistance information (UAI) message.

[0082] Clause 9. The method of clause 8, where the transmitting the UAI message includes transmitting the UAI via a random access channel as part of or following a random access procedure.

[0083] Clause 10. The method of any one of clauses 1 to 9, further including, after the receiving the ODPS configuration: remaining in a power saving mode until the receiving the ODPS.

[0084] Clause 11. A method by a network entity (120), including: receiving, from at least one user equipment (UE) (110), a request (140) for an on-demand pilot signal (ODPS) while the at least one UE (110) is in a radio resource control (RRC) idle or inactive state; transmitting an ODPS configuration (150) to the at least one UE (1 10); transmitting the ODPS (170) during a time period preceding a wake-up signal (WUS) or a paging indication (180) from the network entity (120) to the at least one UE (110); and transmitting the WUS or the paging indication (180) after the ODPS (170).

[0085] Clause 12. The method of clause 11, where the receiving the request includes receiving at least one of: a request for the ODPS configuration, clock drift information, or a proposed parameter for the ODPS configuration, where the proposed parameter for the ODPS configuration includes at least one of a proposed quantity of symbols for the ODPS, a proposed quantity of subbands for the ODPS, or a proposed ODPS pilot pattern.

[0086] Clause 13. The method of clause 1 1 or 12, where the transmitting the ODPS configuration includes indicating at least one of: a quantity of symbols for the ODPS, a quantity of subbands for the ODPS, or an ODPS pilot pattern indicating a sequence or signature of the ODPS.

[0087] Clause 14. The method of any one of clauses 11 to 13, further including: receiving a communication from the at least one UE indicating a discontinuous reception (DRX) cycle of the at least one UE; and determining the ODPS configuration based, at least in part, on the DRX cycle of the at least one UE.

[0088] Clause 15. The method of any one of clauses 11 to 14, where the transmitting the ODPS configuration includes communicating the ODPS configuration via at least one of: a random access response transmission (MSG2) in response to a random access preamble transmission (MSG1) from the at least one UE, a contention resolution transmission (MSG4)in response to a random access request transmission (MSG3) from the at least one UE, or a random access message B (MSGB) in response to a random access message A (MSGA) from the at least one UE.

[0089] Clause 16. The method of any one of clauses 11 to 15, further including: receiving ODPS requests from a plurality of UEs; and determining a common ODPS configuration to satisfy ODPS requests from multiple UEs of the plurality of UEs, where the transmitting the ODPS configuration includes communicating the common ODPS configuration to the multiple UEs.

[0090] Clause 17. The method of clause 16, where the determining the common ODPS configuration includes at least one of selecting a first ODPS configuration for a first UE and using the first ODPS configuration for one or more other UEs that have compatible clock drift information or equivalent requested ODPS pilot patterns as the first UE, or selecting the multiple UEs based on a network criteria and determining the common ODPS configuration that satisfies the ODPS requests from the multiple UEs.

[0091] Clause 18. An apparatus, including: a communication unit; and a processing system configured to control the communication unit to implement any one of the methods of any one of clauses 1 to 17.

[0092] Another innovative aspect of the subject matter described in this disclosure can be implemented as a computer-readable medium having stored therein instructions which, when executed by a processor, causes the processor to perform any one of the above-mentioned functionalities.

[0093] Another innovative aspect of the subject matter described in this disclosure can be implemented as a system having means for implementing any one of the above-mentioned functionalities.

[0094] Another innovative aspect of the subject matter described in this disclosure can be implemented as an apparatus having one or more processors configured to perform one or more operations from any one of the above-mentioned methods.

[0095] As used herein, the terms “component” and “module” are intended to be broadly construed as hardware, firmware, or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, or a combination of hardware andsoftware. As used herein, the phrase “based on” is intended to be broadly construed to mean “based at least in part on.”

[0096] As used herein, a phrase referring to “at least one of’ or “one or more of’ a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.

[0097] In this disclosure, an expression of “X / Y” may include meaning of any of the following: “X or Y” or “X and Y” or “X and / or Y." An expression of “(A) B” or “B (A)” may include concept of “only B.” An expression of “(A) B” or “B (A)” may include the concept of “A+B” or “B+A.”

[0098] In this disclosure, the term "can" indicates a capability, or alternatively indicates a possible implementation option. The term "may" indicates a permission or a possible implementation option.

[0099] Some aspects are described herein in connection with thresholds. As used herein, satisfying a threshold may refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like.

[0100] The various illustrative components, logic, logical blocks, modules, circuits, operations and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware or software, including the structures disclosed in this specification and the structural equivalents thereof. The interchangeability of hardware, firmware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware, firmware or software depends upon the particular application and design constraints imposed on the overall system.

[0101] The hardware and data processing apparatus used to implement the various illustrative components, logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purposesingle- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular processes, operations and methods may be performed by circuitry that is specific to a given function.

[0102] As described above, some aspects of the subject matter described in this specification can be implemented as software. For example, various functions of components disclosed herein, or various blocks or steps of a method, operation, process or algorithm disclosed herein can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor-executable or computer-executable instructions encoded on one or more tangible processor-readable or computer-readable storage media for execution by, or to control the operation of, a data processing apparatus including the components of the devices described herein. By way of example, and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

[0103] As used herein, the terms “user device”, “user equipment” (for example, UE 110), “wireless communication device”, “mobile communication device”, “communication device”, or “mobile device” refer to any one or all of cellular telephones, smartphones, portable computing devices, personal or mobile multi-media players, laptop computers, tablet computers, smartbooks, Internet-of-Things (loT) devices, palm-top computers, wireless electronic mail receivers, multimedia Internet enabled cellular telephones, wireless gaming controllers, display sub-systems, driver assistance systems, vehicle controllers, vehicle system controllers, vehicle communication system, infotainment systems, vehicle telematicssystems or subsystems, vehicle display systems or subsystems, vehicle data controllers, point- of-sale (POS) terminals, health monitoring devices, drones, cameras, media-streaming dongles or another personal media devices, wearable devices such as smartwatches, wireless hotspots, femtocells, broadband routers or other types of routers, and similar electronic devices which include a programmable processor and memory and circuitry configured to perform operations as described herein. Further, the user device in some cases may be embedded in an electronic system such as the head unit of a vehicle or an advanced driver assistance system (ADAS). Still further, a mobile-internet device (MID). Depending on the type, the user device can include one or more general-purpose processors, a computer- readable memory, a user interface, one or more network interfaces, one or more sensors, etc.

[0104] Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

[0105] Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above as acting in particular combinations, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0106] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one or more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously,or between any of the illustrated operations. Tn some circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

[0107] The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects. While the aspects of the disclosure have been described in terms of various examples, any combination of aspects from any of the examples is also within the scope of the disclosure. The examples in this disclosure are provided for pedagogical purposes.

Claims

CLAIMSWhat is claimed is:

1. A method by a user equipment (UE) (110), comprising: transmitting, to a network entity (120) while the UE (110) is in a radio resource control (RRC) idle or inactive state, a request (140) for an on-demand pilot signal (ODPS); receiving an ODPS configuration (150) from the network entity in response to the request (140); receiving the ODPS (170) from the network entity (120) based on the ODPS configuration during a time period preceding a wake-up signal (WUS) or a paging indication (180) from the network entity; and acquiring time and frequency synchronization with the network entity (120) based on the ODPS (170) before receiving the WUS or the paging indication (180).

2. The method of claim 1, wherein the transmitting the request includes transmitting at least one of: a request for the ODPS configuration, clock drift information, or a proposed parameter for the ODPS configuration.

3. The method of claim 2, wherein the proposed parameter for the ODPS configuration includes at least one of: a quantity of symbols for the ODPS, a quantity of subbands for the ODPS, or an ODPS pilot pattern indicating a sequence or signature of the ODPS.

4. The method of claim 2 or 3, wherein the proposed parameter is based, at least in part, on a clock drift rate of the UE.

5. The method of any one of claims 1 to 4, further comprising:transmitting, to the network entity, a communication indicating a discontinuous reception (DRX) cycle of the UE; and wherein the receiving the ODPS from the network entity is also based on the DRX cycle.

6. The method of any one of claims 1 to 5, wherein the transmitting the request includes transmitting the request via at least one of: a random access preamble transmission (MSG1) on a physical random access channel (PRACH), a random access request transmission (MSG3) on a physical uplink shared channel (PUSCH) following a contention based random access, or a random access message A (MSGA) that includes both the random access preamble and random access request.

7. The method of claim 6, wherein the receiving the ODPS configuration from the network entity includes receiving the ODPS configuration via at least one of: a random access response transmission (MSG2) in response to the MSG1, a contention resolution transmission (MSG4) in response to the MSG3, or a random access message B (MSGB) in response to the MSGA.

8. The method of any one of claims 1 to 7, wherein the transmitting the request includes transmitting a UE assistance information (UAI) message.

9. The method of claim 8, wherein the transmitting the UAI message includes transmitting the UAI via a random access channel as part of or following a random access procedure.

10. The method of any one of claims 1 to 9, further comprising, after the receiving the ODPS configuration: remaining in a power saving mode until the receiving the ODPS.

11. A method by a network entity (120), comprising:receiving, from at least one user equipment (UE) (1 10) while the at least one UE (1 10) is in a radio resource control (RRC) idle or inactive state, a request (140) for an on-demand pilot signal (ODPS); transmitting an ODPS configuration (150) to the at least one UE (110); transmitting the ODPS (170) during a time period preceding a wake-up signal (WUS) or a paging indication (180) from the network entity (120) to the at least one UE (110); and transmitting the WUS or the paging indication (180) after the ODPS (170).

12. The method of claim 11, wherein the receiving the request includes receiving at least one of: a request for the ODPS configuration, clock drift information, or a proposed parameter for the ODPS configuration, wherein the proposed parameter for the ODPS configuration includes at least one of a proposed quantity of symbols for the ODPS, a proposed quantity of subbands for the ODPS, or a proposed ODPS pilot pattern.

13. The method of claim 11 or 12, wherein the transmitting the ODPS configuration includes indicating at least one of: a quantity of symbols for the ODPS, a quantity of subbands for the ODPS, or an ODPS pilot pattern indicating a sequence or signature of the ODPS.

14. The method of any one of claims 11 to 13, further comprising: receiving a communication from the at least one UE indicating a discontinuous reception (DRX) cycle of the at least one UE; and determining the ODPS configuration based, at least in part, on the DRX cycle of the at least one UE.

15. The method of any one of claims 11 to 14, wherein the transmitting the ODPS configuration includes communicating the ODPS configuration via at least one of: a random access response transmission (MSG2) in response to a random access preamble transmission (MSG1) from the at least one UE,a contention resolution transmission (MSG4) in response to a random access request transmission (MSG3) from the at least one UE, or a random access message B (MSGB) in response to a random access message A (MSGA) from the at least one UE.

16. The method of any one of claims 11 to 15, further comprising: receiving ODPS requests from a plurality of UEs; and determining a common ODPS configuration to satisfy ODPS requests from multiple UEs of the plurality of UEs, wherein the transmitting the ODPS configuration includes communicating the common ODPS configuration to the multiple UEs.

17. The method of claim 16, wherein the determining the common ODPS configuration includes at least one of: selecting a first ODPS configuration for a first UE and using the first ODPS configuration for one or more other UEs that have compatible clock drift information or equivalent requested ODPS pilot patterns as the first UE, or selecting the multiple UEs based on a network criteria and determining the common ODPS configuration that satisfies the ODPS requests from the multiple UEs.

18. An apparatus, comprising: a communication unit; and a processing system configured to control the communication unit to implement any one of the methods of any one of claims 1 to 17.

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