Patent Description:
Wireless communication systems have developed through various generations, including a first-generation analog wireless phone service (<NUM>), a second-generation (<NUM>) digital wireless phone service (including interim <NUM> networks), a third-generation (<NUM>) high speed data, Internet-capable wireless service, and a fourth-generation (<NUM>) service (e.g., Long-Term Evolution (LTE), WiMax). There are presently many different types of wireless communication systems in use, including cellular and personal communications service (PCS) systems. Examples of known cellular systems include the cellular Analog Advanced Mobile Phone System (AMPS), and digital cellular systems based on code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), the Global System for Mobile communication (GSM), etc..

A fifth generation (<NUM>) mobile standard calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The <NUM> standard (also referred to as "New Radio" or "NR"), according to the Next Generation Mobile Networks Alliance, is designed to provide data rates of several tens of megabits per second to each of tens of thousands of users, with <NUM> gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large sensor deployments. Consequently, the spectral efficiency of <NUM> mobile communications should be significantly enhanced compared to the current <NUM> / LTE standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards.

<CIT> discloses a PRS configured in at least one downlink subframe among a plurality of downlink subframes. The PRS may be transmitted in the at least one downlink subframe using an unlicensed radio frequency spectrum band. Prior to transmitting data over an unlicensed radio frequency spectrum band, a transmitting apparatus may perform a clear channel assessment (CCA) procedure to gain access to the unlicensed radio frequency spectrum band. A CCA procedure may determine whether a particular channel of the unlicensed radio frequency spectrum band is available. When it is determined that the channel of the unlicensed radio frequency spectrum band is not available (e.g., because another device is already using the channel of the unlicensed radio frequency spectrum band), a CCA may be performed for the channel of the unlicensed radio frequency spectrum band again at a later time.

<NPL> discloses that, since an unlicensed spectrum can be utilized by any applications such as licensed assisted access (LAA)-capable LTE eNB/UE, WLAN AP, or PRS-only transmission device (i.e., PRS beacon), it would be beneficial to consider positioning on unlicensed spectrum in this study item. However, in some region such as Europe and Japan, the device can transmit PRS on unlicensed spectrum only when a channel is un-occupied (i.e., idle) after listen before talk (LBT) operation to avoid interference or collision with other device.

<CIT> discloses a data transmission method and station, relating to the field of wireless communications, that relates to using the resources other than the resources corresponding to CCA duration. The method comprises: after a station successfully executes CCA/eCCA in a subframe, the station sends PSS and/or SSS in the entire LTE OFDM symbol in occupied subframe resources.

The following presents a simplified summary relating to one or more aspects disclosed herein. Thus, the following summary should not be considered an extensive overview relating to all contemplated aspects, nor should the following summary be considered to identify key or critical elements relating to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the following summary has the sole purpose to present certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below.

As used herein, the terms "user equipment" (UE) and "base station" are not intended to be specific or otherwise limited to any particular radio access technology (RAT), unless otherwise noted. In general, a UE may be any wireless communication device (e.g., a mobile phone, router, tablet computer, laptop computer, tracking device, wearable (e.g., smartwatch, glasses, augmented reality (AR) / virtual reality (VR) headset, etc.), vehicle (e.g., automobile, motorcycle, bicycle, etc.), Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communications network. A UE may be mobile or may (e.g., at certain times) be stationary, and may communicate with a radio access network (RAN). As used herein, the term "UE" may be referred to interchangeably as an "access terminal" or "AT," a "client device," a "wireless device," a "subscriber device," a "subscriber terminal," a "subscriber station," a "user terminal" or UT, a "mobile device," a "mobile terminal," a "mobile station," or variations thereof. Generally, UEs can communicate with a core network via a RAN, and through the core network the UEs can be connected with external networks such as the Internet and with other UEs. Of course, other mechanisms of connecting to the core network and/or the Internet are also possible for the UEs, such as over wired access networks, wireless local area network (WLAN) networks (e.g., based on IEEE <NUM>, etc.) and so on.

A base station may operate according to one of several RATs in communication with UEs depending on the network in which it is deployed, and may be alternatively referred to as an access point (AP), a network node, a NodeB, an evolved NodeB (eNB), a next generation eNB (ng-eNB), a New Radio (NR) Node B (also referred to as a gNB or gNodeB), etc. A base station may be used primarily to support wireless access by UEs, including supporting data, voice, and/or signaling connections for the supported UEs. In some systems a base station may provide purely edge node signaling functions while in other systems it may provide additional control and/or network management functions. A communication link through which UEs can send signals to a base station is called an uplink (UL) channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc.). A communication link through which the base station can send signals to UEs is called a downlink (DL) or forward link channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc.). As used herein the term traffic channel (TCH) can refer to either an uplink / reverse or downlink / forward traffic channel.

The term "base station" may refer to a single physical transmission-reception point (TRP) or to multiple physical TRPs that may or may not be co-located. For example, where the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to a cell (or several cell sectors) of the base station. Where the term "base station" refers to multiple co-located physical TRPs, the physical TRPs may be an array of antennas (e.g., as in a multiple-input multiple-output (MIMO) system or where the base station employs beamforming) of the base station. Where the term "base station" refers to multiple non-co-located physical TRPs, the physical TRPs may be a distributed antenna system (DAS) (a network of spatially separated antennas connected to a common source via a transport medium) or a remote radio head (RRH) (a remote base station connected to a serving base station). Alternatively, the non-co-located physical TRPs may be the serving base station receiving the measurement report from the UE and a neighbor base station whose reference RF signals (or simply "reference signals") the UE is measuring. Because a TRP is the point from which a base station transmits and receives wireless signals, as used herein, references to transmission from or reception at a base station are to be understood as referring to a particular TRP of the base station.

In some implementations that support positioning of UEs, a base station may not support wireless access by UEs (e.g., may not support data, voice, and/or signaling connections for UEs), but may instead transmit reference signals to UEs to be measured by the UEs, and/or may receive and measure signals transmitted by the UEs. Such a base station may be referred to as a positioning beacon (e.g., when transmitting signals to UEs) and/or as a location measurement unit (e.g., when receiving and measuring signals from UEs).

An "RF signal" comprises an electromagnetic wave of a given frequency that transports information through the space between a transmitter and a receiver. As used herein, a transmitter may transmit a single "RF signal" or multiple "RF signals" to a receiver. However, the receiver may receive multiple "RF signals" corresponding to each transmitted RF signal due to the propagation characteristics of RF signals through multipath channels. The same transmitted RF signal on different paths between the transmitter and receiver may be referred to as a "multipath" RF signal. As used herein, an RF signal may also be referred to as a "wireless signal" or simply a "signal" where it is clear from the context that the term "signal" refers to a wireless signal or an RF signal.

According to various aspects, <FIG> illustrates an exemplary wireless communications system <NUM>. The wireless communications system <NUM> (which may also be referred to as a wireless wide area network (WWAN)) may include various base stations <NUM> and various UEs <NUM>. The base stations <NUM> may include macro cell base stations (high power cellular base stations) and/or small cell base stations (low power cellular base stations). In an aspect, the macro cell base station may include eNBs and/or ng-eNBs where the wireless communications system <NUM> corresponds to an LTE network, or gNBs where the wireless communications system <NUM> corresponds to a NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc..

The base stations <NUM> may collectively form a RAN and interface with a core network <NUM> (e.g., an evolved packet core (EPC) or a <NUM> core (5GC)) through backhaul links <NUM>, and through the core network <NUM> to one or more location servers <NUM> (which may be part of core network <NUM> or may be external to core network <NUM>). In addition to other functions, the base stations <NUM> may perform functions that relate to one or more of transferring user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, RAN sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations <NUM> may communicate with each other directly or indirectly (e.g., through the EPC / 5GC) over backhaul links <NUM>, which may be wired or wireless.

In an aspect, one or more cells may be supported by a base station <NUM> in each geographic coverage area <NUM>. A "cell" is a logical communication entity used for communication with a base station (e.g., over some frequency resource, referred to as a carrier frequency, component carrier, carrier, band, or the like), and may be associated with an identifier (e.g., a physical cell identifier (PCI), a virtual cell identifier (VCI), a cell global identifier (CGI)) for distinguishing cells operating via the same or a different carrier frequency. In some cases, different cells may be configured according to different protocol types (e.g., machine-type communication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB), or others) that may provide access for different types of UEs. Because a cell is supported by a specific base station, the term "cell" may refer to either or both of the logical communication entity and the base station that supports it, depending on the context. In addition, because a TRP is typically the physical transmission point of a cell, the terms "cell" and "TRP" may be used interchangeably. In some cases, the term "cell" may also refer to a geographic coverage area of a base station (e.g., a sector), insofar as a carrier frequency can be detected and used for communication within some portion of geographic coverage areas <NUM>.

While neighboring macro cell base station <NUM> geographic coverage areas <NUM> may partially overlap (e.g., in a handover region), some of the geographic coverage areas <NUM> may be substantially overlapped by a larger geographic coverage area <NUM>. For example, a small cell base station <NUM>' may have a geographic coverage area <NUM>' that substantially overlaps with the geographic coverage area <NUM> of one or more macro cell base stations <NUM>. A network that includes both small cell and macro cell base stations may be known as a heterogeneous network. A heterogeneous network may also include home eNBs (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG).

The communication links <NUM> between the base stations <NUM> and the UEs <NUM> may include uplink (also referred to as reverse link) transmissions from a UE <NUM> to a base station <NUM> and/or downlink (also referred to as forward link) transmissions from a base station <NUM> to a UE <NUM>. The communication links <NUM> may use MIMO antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links <NUM> may be through one or more carrier frequencies. Allocation of carriers may be asymmetric with respect to downlink and uplink (e.g., more or less carriers may be allocated for downlink than for uplink).

More specifically, LBT is a mechanism by which a transmitter (e.g., a UE on the uplink or a base station on the downlink) applies CCA before using the channel/subband. Thus, before transmission, the transmitter performs a CCA check and listens on the channel/subband for the duration of the CCA observation time, which should not be less than some threshold (e.g., <NUM> microseconds). The channel may be considered occupied if the energy level in the channel exceeds some threshold (proportional to the transmit power of the transmitter). If the channel is occupied, the transmitter should delay further attempts to access the medium by some random factor (e.g., some number between one and <NUM>) times the CCA observation time. If the channel is not occupied, the transmitter can begin transmitting. However, the maximum contiguous transmission time on the channel should be less than some threshold, such as five milliseconds.

Receive beams may be spatially related. A spatial relation means that parameters for a transmit beam for a second reference signal can be derived from information about a receive beam for a first reference signal. For example, a UE may use a particular receive beam to receive one or more reference downlink reference signals (e.g., positioning reference signals (PRS), navigation reference signals (NRS), tracking reference signals (TRS), phase tracking reference signal (PTRS), cell-specific reference signals (CRS), channel state information reference signals (CSI-RS), primary synchronization signals (PSS), secondary synchronization signals (SSS), synchronization signal blocks (SSBs), etc.) from a base station. The UE can then form a transmit beam for sending one or more uplink reference signals (e.g., uplink positioning reference signals (UL-PRS), sounding reference signal (SRS), demodulation reference signals (DMRS), etc.) to that base station based on the parameters of the receive beam.

In <NUM>, the frequency spectrum in which wireless nodes (e.g., base stations <NUM>/<NUM>, UEs <NUM>/<NUM>) operate is divided into multiple frequency ranges, FR1 (from <NUM> to <NUM>), FR2 (from <NUM> to <NUM>), FR3 (above <NUM>), and FR4 (between FR1 and FR2). In a multi-carrier system, such as <NUM>, one of the carrier frequencies is referred to as the "primary carrier" or "anchor carrier" or "primary serving cell" or "PCell," and the remaining carrier frequencies are referred to as "secondary carriers" or "secondary serving cells" or "SCells. " In carrier aggregation, the anchor carrier is the carrier operating on the primary frequency (e.g., FR1) utilized by a UE <NUM>/<NUM> and the cell in which the UE <NUM>/<NUM> either performs the initial radio resource control (RRC) connection establishment procedure or initiates the RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels, and may be a carrier in a licensed frequency (however, this is not always the case). A secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once the RRC connection is established between the UE <NUM> and the anchor carrier and that may be used to provide additional radio resources. In some cases, the secondary carrier may be a carrier in an unlicensed frequency. The secondary carrier may contain only necessary signaling information and signals, for example, those that are UE-specific may not be present in the secondary carrier, since both primary uplink and downlink carriers are typically UE-specific. This means that different UEs <NUM>/<NUM> in a cell may have different downlink primary carriers. The same is true for the uplink primary carriers. The network is able to change the primary carrier of any UE <NUM>/<NUM> at any time. This is done, for example, to balance the load on different carriers. Because a "serving cell" (whether a PCell or an SCell) corresponds to a carrier frequency / component carrier over which some base station is communicating, the term "cell," "serving cell," "component carrier," "carrier frequency," and the like can be used interchangeably.

The wireless communications system <NUM> may further include one or more UEs, such as UE <NUM>, that connects indirectly to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links. In the example of <FIG>, UE <NUM> has a D2D P2P link <NUM> with one of the UEs <NUM> connected to one of the base stations <NUM> (e.g., through which UE <NUM> may indirectly obtain cellular connectivity) and a D2D P2P link <NUM> with WLAN STA <NUM> connected to the WLAN AP <NUM> (through which UE <NUM> may indirectly obtain WLAN-based Internet connectivity). In an example, the D2D P2P links <NUM> and <NUM> may be supported with any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, and so on.

The wireless communications system <NUM> may further include a UE <NUM> that may communicate with a macro cell base station <NUM> over a communication link <NUM> and/or the mmW base station <NUM> over a mmW communication link <NUM>. For example, the macro cell base station <NUM> may support a PCell and one or more SCells for the UE <NUM> and the mmW base station <NUM> may support one or more SCells for the UE <NUM>.

According to various aspects, <FIG> illustrates an example wireless network structure <NUM>. For example, a 5GC <NUM> (also referred to as a Next Generation Core (NGC)) can be viewed functionally as control plane functions <NUM> (e.g., UE registration, authentication, network access, gateway selection, etc.) and user plane functions <NUM>, (e.g., UE gateway function, access to data networks, IP routing, etc.) which operate cooperatively to form the core network. User plane interface (NG-U) <NUM> and control plane interface (NG-C) <NUM> connect the gNB <NUM> to the 5GC <NUM> and specifically to the control plane functions <NUM> and user plane functions <NUM>. In an additional configuration, an ng-eNB <NUM> may also be connected to the 5GC <NUM> via NG-C <NUM> to the control plane functions <NUM> and NG-U <NUM> to user plane functions <NUM>. Further, ng-eNB <NUM> may directly communicate with gNB <NUM> via a backhaul connection <NUM>. In some configurations, the New RAN <NUM> may only have one or more gNBs <NUM>, while other configurations include one or more of both ng-eNBs <NUM> and gNBs <NUM>. Either gNB <NUM> or ng-eNB <NUM> may communicate with UEs <NUM> (e.g., any of the UEs depicted in <FIG>). Another optional aspect may include location server <NUM>, which may be in communication with the 5GC <NUM> to provide location assistance for UEs <NUM>. The location server <NUM> can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server. The location server <NUM> can be configured to support one or more location services for UEs <NUM> that can connect to the location server <NUM> via the core network, 5GC <NUM>, and/or via the Internet (not illustrated). Further, the location server <NUM> may be integrated into a component of the core network, or alternatively may be external to the core network.

According to various aspects, <FIG> illustrates another example wireless network structure <NUM>. For example, a 5GC <NUM> can be viewed functionally as control plane functions, provided by an access and mobility management function (AMF) <NUM>, and user plane functions, provided by a user plane function (UPF) <NUM>, which operate cooperatively to form the core network (i.e., 5GC <NUM>). User plane interface <NUM> and control plane interface <NUM> connect the ng-eNB <NUM> to the 5GC <NUM> and specifically to UPF <NUM> and AMF <NUM>, respectively. In an additional configuration, a gNB <NUM> may also be connected to the 5GC <NUM> via control plane interface <NUM> to AMF <NUM> and user plane interface <NUM> to UPF <NUM>. Further, ng-eNB <NUM> may directly communicate with gNB <NUM> via the backhaul connection <NUM>, with or without gNB direct connectivity to the 5GC <NUM>. In some configurations, the New RAN <NUM> may only have one or more gNBs <NUM>, while other configurations include one or more of both ng-eNBs <NUM> and gNBs <NUM>. Either gNB <NUM> or ng-eNB <NUM> may communicate with UEs <NUM> (e.g., any of the UEs depicted in <FIG>). The base stations of the New RAN <NUM> communicate with the AMF <NUM> over the N2 interface and with the UPF <NUM> over the N3 interface.

The functions of the AMF <NUM> include registration management, connection management, reachability management, mobility management, lawful interception, transport for session management (SM) messages between the UE <NUM> and a session management function (SMF) <NUM>, transparent proxy services for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE <NUM> and the short message service function (SMSF) (not shown), and security anchor functionality (SEAF). The AMF <NUM> also interacts with an authentication server function (AUSF) (not shown) and the UE <NUM>, and receives the intermediate key that was established as a result of the UE <NUM> authentication process. In the case of authentication based on a UMTS (universal mobile telecommunications system) subscriber identity module (USIM), the AMF <NUM> retrieves the security material from the AUSF. The functions of the AMF <NUM> also include security context management (SCM). The SCM receives a key from the SEAF that it uses to derive access-network specific keys. The functionality of the AMF <NUM> also includes location services management for regulatory services, transport for location services messages between the UE <NUM> and a location management function (LMF) <NUM> (which acts as a location server <NUM>), transport for location services messages between the New RAN <NUM> and the LMF <NUM>, evolved packet system (EPS) bearer identifier allocation for interworking with the EPS, and UE <NUM> mobility event notification. In addition, the AMF <NUM> also supports functionalities for non-3GPP access networks.

Functions of the UPF <NUM> include acting as an anchor point for intra-/inter-RAT mobility (when applicable), acting as an external protocol data unit (PDU) session point of interconnect to a data network (not shown), providing packet routing and forwarding, packet inspection, user plane policy rule enforcement (e.g., gating, redirection, traffic steering), lawful interception (user plane collection), traffic usage reporting, quality of service (QoS) handling for the user plane (e.g., uplink/downlink rate enforcement, reflective QoS marking in the downlink), uplink traffic verification (service data flow (SDF) to QoS flow mapping), transport level packet marking in the uplink and downlink, downlink packet buffering and downlink data notification triggering, and sending and forwarding of one or more "end markers" to the source RAN node. The UPF <NUM> may also support transfer of location services messages over a user plane between the UE <NUM> and a location server, such as a secure user plane location (SUPL) location platform (SLP) <NUM>.

The functions of the SMF <NUM> include session management, UE Internet protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering at the UPF <NUM> to route traffic to the proper destination, control of part of policy enforcement and QoS, and downlink data notification. The interface over which the SMF <NUM> communicates with the AMF <NUM> is referred to as the N11 interface.

Another optional aspect may include an LMF <NUM>, which may be in communication with the 5GC <NUM> to provide location assistance for UEs <NUM>. The LMF <NUM> can be implemented as a plurality of separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternately may each correspond to a single server. The LMF <NUM> can be configured to support one or more location services for UEs <NUM> that can connect to the LMF <NUM> via the core network, 5GC <NUM>, and/or via the Internet (not illustrated). The SLP <NUM> may support similar functions to the LMF <NUM>, but whereas the LMF <NUM> may communicate with the AMF <NUM>, New RAN <NUM>, and UEs <NUM> over a control plane (e.g., using interfaces and protocols intended to convey signaling messages and not voice or data), the SLP <NUM> may communicate with UEs <NUM> and external clients (not shown in <FIG>) over a user plane (e.g., using protocols intended to carry voice and/or data like the transmission control protocol (TCP) and/or IP).

<FIG>, <FIG>, and <FIG> illustrate several exemplary components (represented by corresponding blocks) that may be incorporated into a UE <NUM> (which may correspond to any of the UEs described herein), a base station <NUM> (which may correspond to any of the base stations described herein), and a network entity <NUM> (which may correspond to or embody any of the network functions described herein, including the location server <NUM>, the LMF <NUM>, and the SLP <NUM>) to support the file transmission operations as taught herein. It will be appreciated that these components may be implemented in different types of apparatuses in different implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other apparatuses in a communication system. For example, other apparatuses in a system may include components similar to those described to provide similar functionality. Also, a given apparatus may contain one or more of the components. For example, an apparatus may include multiple transceiver components that enable the apparatus to operate on multiple carriers and/or communicate via different technologies.

The UE <NUM> and the base station <NUM> each include wireless wide area network (WWAN) transceiver <NUM> and <NUM>, respectively, configured to communicate via one or more wireless communication networks (not shown), such as an NR network, an LTE network, a GSM network, and/or the like. The WWAN transceivers <NUM> and <NUM> may be connected to one or more antennas <NUM> and <NUM>, respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., ng-eNBs, gNBs), etc., via at least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wireless communication medium of interest (e.g., some set of time/frequency resources in a particular frequency spectrum). The WWAN transceivers <NUM> and <NUM> may be variously configured for transmitting and encoding signals <NUM> and <NUM> (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals <NUM> and <NUM> (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the WWAN transceivers <NUM> and <NUM> include one or more transmitters <NUM> and <NUM>, respectively, for transmitting and encoding signals <NUM> and <NUM>, respectively, and one or more receivers <NUM> and <NUM>, respectively, for receiving and decoding signals <NUM> and <NUM>, respectively.

The UE <NUM> and the base station <NUM> also include, at least in some cases, wireless local area network (WLAN) transceivers <NUM> and <NUM>, respectively. The WLAN transceivers <NUM> and <NUM> may be connected to one or more antennas <NUM> and <NUM>, respectively, for communicating with other network nodes, such as other UEs, access points, base stations, etc., via at least one designated RAT (e.g., WiFi, LTE-D, Bluetooth®, etc.) over a wireless communication medium of interest. The WLAN transceivers <NUM> and <NUM> may be variously configured for transmitting and encoding signals <NUM> and <NUM> (e.g., messages, indications, information, and so on), respectively, and, conversely, for receiving and decoding signals <NUM> and <NUM> (e.g., messages, indications, information, pilots, and so on), respectively, in accordance with the designated RAT. Specifically, the transceivers <NUM> and <NUM> include one or more transmitters <NUM> and <NUM>, respectively, for transmitting and encoding signals <NUM> and <NUM>, respectively, and one or more receivers <NUM> and <NUM>, respectively, for receiving and decoding signals <NUM> and <NUM>, respectively.

Transceiver circuitry including at least one transmitter and at least one receiver may comprise an integrated device (e.g., embodied as a transmitter circuit and a receiver circuit of a single communication device) in some implementations, may comprise a separate transmitter device and a separate receiver device in some implementations, or may be embodied in other ways in other implementations. In an aspect, a transmitter may include or be coupled to a plurality of antennas (e.g., antennas <NUM>, <NUM>, <NUM>, <NUM>), such as an antenna array, that permits the respective apparatus to perform transmit "beamforming," as described herein. Similarly, a receiver may include or be coupled to a plurality of antennas (e.g., antennas <NUM>, <NUM>, <NUM>, <NUM>), such as an antenna array, that permits the respective apparatus to perform receive beamforming, as described herein. In an aspect, the transmitter and receiver may share the same plurality of antennas (e.g., antennas <NUM>, <NUM>, <NUM>, <NUM>), such that the respective apparatus can only receive or transmit at a given time, not both at the same time. A wireless communication device (e.g., one or both of the transceivers <NUM> and <NUM> and/or <NUM> and <NUM>) of the UE <NUM> and/or the base station <NUM> may also comprise a network listen module (NLM) or the like for performing various measurements.

The UE <NUM> and the base station <NUM> also include, at least in some cases, satellite positioning systems (SPS) receivers <NUM> and <NUM>. The SPS receivers <NUM> and <NUM> may be connected to one or more antennas <NUM> and <NUM>, respectively, for receiving SPS signals <NUM> and <NUM>, respectively, such as global positioning system (GPS) signals, global navigation satellite system (GLONASS) signals, Galileo signals, Beidou signals, Indian Regional Navigation Satellite System (NAVIC), Quasi-Zenith Satellite System (QZSS), etc. The SPS receivers <NUM> and <NUM> may comprise any suitable hardware and/or software for receiving and processing SPS signals <NUM> and <NUM>, respectively. The SPS receivers <NUM> and <NUM> request information and operations as appropriate from the other systems, and performs calculations necessary to determine positions of the UE <NUM> and the base station <NUM> using measurements obtained by any suitable SPS algorithm.

The base station <NUM> and the network entity <NUM> each include at least one network interfaces <NUM> and <NUM> for communicating with other network entities. For example, the network interfaces <NUM> and <NUM> (e.g., one or more network access ports) may be configured to communicate with one or more network entities via a wire-based or wireless backhaul connection. In some aspects, the network interfaces <NUM> and <NUM> may be implemented as transceivers configured to support wire-based or wireless signal communication. This communication may involve, for example, sending and receiving messages, parameters, and/or other types of information.

The UE <NUM>, the base station <NUM>, and the network entity <NUM> also include other components that may be used in conjunction with the operations as disclosed herein. The UE <NUM> includes processor circuitry implementing a processing system <NUM> for providing functionality relating to, for example, positioning operations, and for providing other processing functionality. The base station <NUM> includes a processing system <NUM> for providing functionality relating to, for example, positioning operations as disclosed herein, and for providing other processing functionality. The network entity <NUM> includes a processing system <NUM> for providing functionality relating to, for example, positioning operations as disclosed herein, and for providing other processing functionality. In an aspect, the processing systems <NUM>, <NUM>, and <NUM> may include, for example, one or more general purpose processors, multi-core processors, ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGA), or other programmable logic devices or processing circuitry.

The UE <NUM>, the base station <NUM>, and the network entity <NUM> include memory circuitry implementing memory components <NUM>, <NUM>, and <NUM> (e.g., each including a memory device), respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on). In some cases, the UE <NUM>, the base station <NUM>, and the network entity <NUM> may include reporting managers <NUM>, <NUM>, and <NUM>, respectively. The reporting managers <NUM>, <NUM>, and <NUM> may be hardware circuits that are part of or coupled to the processing systems <NUM>, <NUM>, and <NUM>, respectively, that, when executed, cause the UE <NUM>, the base station <NUM>, and the network entity <NUM> to perform the functionality described herein. In other aspects, the reporting managers <NUM>, <NUM>, and <NUM> may be external to the processing systems <NUM>, <NUM>, and <NUM> (e.g., part of a modem processing system, integrated with another processing system, etc.). Alternatively, the reporting managers <NUM>, <NUM>, and <NUM> may be memory modules (as shown in <FIG>) stored in the memory components <NUM>, <NUM>, and <NUM>, respectively, that, when executed by the processing systems <NUM>, <NUM>, and <NUM> (or a modem processing system, another processing system, etc.), cause the UE <NUM>, the base station <NUM>, and the network entity <NUM> to perform the functionality described herein.

The UE <NUM> may include one or more sensors <NUM> coupled to the processing system <NUM> to provide movement and/or orientation information that is independent of motion data derived from signals received by the WWAN transceiver <NUM>, the WLAN transceiver <NUM>, and/or the SPS receiver <NUM>. By way of example, the sensor(s) <NUM> may include an accelerometer (e.g., a micro-electrical mechanical systems (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric pressure altimeter), and/or any other type of movement detection sensor. Moreover, the sensor(s) <NUM> may include a plurality of different types of devices and combine their outputs in order to provide motion information. For example, the sensor(s) <NUM> may use a combination of a multi-axis accelerometer and orientation sensors to provide the ability to compute positions in 2D and/or 3D coordinate systems.

In addition, the UE <NUM> includes a user interface <NUM> for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on). Although not shown, the base station <NUM> and the network entity <NUM> may also include user interfaces.

Referring to the processing system <NUM> in more detail, in the downlink, IP packets from the network entity <NUM> may be provided to the processing system <NUM>. The processing system <NUM> may implement functionality for an RRC layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The processing system <NUM> may provide RRC layer functionality associated with broadcasting of system information (e.g., master information block (MIB), system information blocks (SIBs)), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-RAT mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction through automatic repeat request (ARQ), concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

The transmitter <NUM> and the receiver <NUM> may implement Layer-<NUM> functionality associated with various signal processing functions. Layer-<NUM>, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The transmitter <NUM> handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). Each stream may then be mapped to an orthogonal frequency division multiplexing (OFDM) subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM symbol stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator may be used to determine the coding and modulation scheme, as well as for spatial processing. Each spatial stream may then be provided to one or more different antennas <NUM>. The transmitter <NUM> may modulate an RF carrier with a respective spatial stream for transmission.

At the UE <NUM>, the receiver <NUM> receives a signal through its respective antenna(s) <NUM>. The receiver <NUM> recovers information modulated onto an RF carrier and provides the information to the processing system <NUM>. The transmitter <NUM> and the receiver <NUM> implement Layer-<NUM> functionality associated with various signal processing functions. The receiver <NUM> may perform spatial processing on the information to recover any spatial streams destined for the UE <NUM>. If multiple spatial streams are destined for the UE <NUM>, they may be combined by the receiver <NUM> into a single OFDM symbol stream. The receiver <NUM> then converts the OFDM symbol stream from the time-domain to the frequency domain using a fast Fourier transform (FFT). These soft decisions may be based on channel estimates computed by a channel estimator. The soft decisions are then decoded and de-interleaved to recover the data and control signals that were originally transmitted by the base station <NUM> on the physical channel. The data and control signals are then provided to the processing system <NUM>, which implements Layer-<NUM> and Layer-<NUM> functionality.

In the uplink, the processing system <NUM> provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the core network. The processing system <NUM> is also responsible for error detection.

Similar to the functionality described in connection with the downlink transmission by the base station <NUM>, the processing system <NUM> provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through hybrid automatic repeat request (HARQ), priority handling, and logical channel prioritization.

Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station <NUM> may be used by the transmitter <NUM> to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the transmitter <NUM> may be provided to different antenna(s) <NUM>. The transmitter <NUM> may modulate an RF carrier with a respective spatial stream for transmission.

The uplink transmission is processed at the base station <NUM> in a manner similar to that described in connection with the receiver function at the UE <NUM>. The receiver <NUM> receives a signal through its respective antenna(s) <NUM>. The receiver <NUM> recovers information modulated onto an RF carrier and provides the information to the processing system <NUM>.

In the uplink, the processing system <NUM> provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the UE <NUM>. IP packets from the processing system <NUM> may be provided to the core network. The processing system <NUM> is also responsible for error detection.

For convenience, the UE <NUM>, the base station <NUM>, and/or the network entity <NUM> are shown in <FIG> as including various components that may be configured according to the various examples described herein. It will be appreciated, however, that the illustrated blocks may have different functionality in different designs.

The various components of the UE <NUM>, the base station <NUM>, and the network entity <NUM> may communicate with each other over data buses <NUM>, <NUM>, and <NUM>, respectively. The components of <FIG> may be implemented in various ways. In some implementations, the components of <FIG> may be implemented in one or more circuits such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors). Here, each circuit may use and/or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality. For example, some or all of the functionality represented by blocks <NUM> to <NUM> may be implemented by processor and memory component(s) of the UE <NUM> (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Similarly, some or all of the functionality represented by blocks <NUM> to <NUM> may be implemented by processor and memory component(s) of the base station <NUM> (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Also, some or all of the functionality represented by blocks <NUM> to <NUM> may be implemented by processor and memory component(s) of the network entity <NUM> (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). For simplicity, various operations, acts, and/or functions are described herein as being performed "by a UE," "by a base station," "by a positioning entity," etc. However, as will be appreciated, such operations, acts, and/or functions may actually be performed by specific components or combinations of components of the UE, base station, positioning entity, etc., such as the processing systems <NUM>, <NUM>, <NUM>, the transceivers <NUM>, <NUM>, <NUM>, and <NUM>, the memory components <NUM>, <NUM>, and <NUM>, the reporting managers <NUM>, <NUM>, and <NUM>, etc..

Various frame structures may be used to support downlink and uplink transmissions between network nodes (e.g., base stations and UEs). <FIG> is a diagram <NUM> illustrating an example of a downlink frame structure, according to aspects of the disclosure. Other wireless communications technologies may have different frame structures and/or different channels.

LTE, and in some cases NR, utilizes OFDM on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. Unlike LTE, however, NR has an option to use OFDM on the uplink as well. For example, the spacing of the subcarriers may be <NUM> and the minimum resource allocation (resource block) may be <NUM> subcarriers (or <NUM>). Consequently, the nominal FFT size may be equal to <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> megahertz (MHz), respectively. For example, a subband may cover <NUM> (i.e., <NUM> resource blocks), and there may be <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> subbands for system bandwidth of <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, respectively.

LTE supports a single numerology (subcarrier spacing, symbol length, etc.). In contrast, NR may support multiple numerologies (µ), for example, subcarrier spacing of <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> or greater may be available. Table <NUM> provided below lists some various parameters for different NR numerologies.

In the example of <FIG>, a numerology of <NUM> is used. Thus, in the time domain, a frame (e.g., <NUM>) is divided into <NUM> equally sized subframes of <NUM> each, and each subframe includes one time slot. In <FIG>, time is represented horizontally (e.g., on the X axis) with time increasing from left to right, while frequency is represented vertically (e.g., on the Y axis) with frequency increasing (or decreasing) from bottom to top.

A resource grid may be used to represent time slots, each time slot including one or more time-concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)) in the frequency domain. The resource grid is further divided into multiple resource elements (REs). An RE may correspond to one symbol length in the time domain and one subcarrier in the frequency domain. In the numerology of <FIG>, for a normal cyclic prefix, an RB may contain <NUM> consecutive subcarriers in the frequency domain and seven consecutive symbols in the time domain, for a total of <NUM> REs. For an extended cyclic prefix, an RB may contain <NUM> consecutive subcarriers in the frequency domain and six consecutive symbols in the time domain, for a total of <NUM> REs.

As illustrated in <FIG>, some of the REs carry downlink reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS may include DMRS, CSI-RS, CRS, PRS, NRS, TRS, etc., exemplary locations of which are labeled "R" in <FIG>.

A collection of resource elements (REs) that are used for transmission of PRS is referred to as a "PRS resource. " The collection of resource elements can span multiple PRBs in the frequency domain and N (e.g., <NUM> or more) consecutive symbol(s) within a slot in the time domain. In a given OFDM symbol in the time domain, a PRS resource occupies consecutive PRBs in the frequency domain.

A "PRS resource set" is a set of PRS resources used for the transmission of PRS signals, where each PRS resource has a PRS resource ID. In addition, the PRS resources in a PRS resource set are associated with the same TRP. A PRS resource set is identified by a PRS resource set ID and is associated with a particular TRP (identified by a cell ID). In addition, the PRS resources in a PRS resource set have the same periodicity, a common muting pattern configuration, and the same repetition factor across slots. The periodicity may have a length selected from <NUM>m·{<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>} slots, with µ = <NUM>, <NUM>, <NUM>, <NUM>. The repetition factor may have a length selected from {<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>} slots.

A PRS resource ID in a PRS resource set is associated with a single beam (and/or beam ID) transmitted from a single TRP (where a TRP may transmit one or more beams). That is, each PRS resource of a PRS resource set may be transmitted on a different beam, and as such, a "PRS resource," or simply "resource," can also be referred to as a "beam. " Note that this does not have any implications on whether the TRPs and the beams on which PRS are transmitted are known to the UE.

A "PRS instance" or "PRS occasion" is one instance of a periodically repeated time window (e.g., a group of one or more consecutive slots) where PRS are expected to be transmitted. A PRS occasion may also be referred to as a "PRS positioning occasion," a "PRS positioning instance, a "positioning occasion," a "positioning instance," a "positioning reference," or simply an "occasion," an "instance," or a "repetition.

Note that the terms "positioning reference signal" and "PRS" may sometimes refer to specific reference signals that are used for positioning in LTE systems. However, as used herein, unless otherwise indicated, the terms "positioning reference signal" and "PRS" refer to any type of reference signal that can be used for positioning, such as but not limited to, PRS in LTE, NRS in <NUM>, TRS, PTRS, CRS, CSI-RS, DMRS, PSS, SSS, SSB, SRS, UL-PRS, etc. In addition, the terms "positioning reference signal" and "PRS" refers to downlink or uplink reference signals, unless otherwise indicated.

There are currently two alternatives for periodic PRS resource allocation. The first alterative is that the periodicity of downlink PRS resources is configured at the downlink PRS resource set level. In this case, a common period is used for downlink PRS resources within a downlink PRS resource set. The second alternative is that the periodicity of downlink PRS resources is configured at the downlink PRS resource level. In this case, different periods can be used for downlink PRS resources within a downlink PRS resource set.

<FIG> illustrates an exemplary PRS configuration <NUM> for a cell/TRP supported by a wireless node (e.g., a base station). <FIG> shows how PRS positioning occasions are determined by a system frame number (SFN), a cell-specific subframe offset (ΔPRS) <NUM>, and a PRS periodicity (TPRS) <NUM>. Typically, the cell-specific PRS subframe configuration is defined by a PRS configuration index (IPRS) included in positioning assistance data. The PRS periodicity (TPRS) <NUM> and the cell-specific subframe offset (ΔPRS) are defined based on the PRS configuration index (IPRS), as illustrated in Table <NUM> below.

A PRS configuration is defined with reference to the SFN of the cell that transmits PRS. PRS instances, for the first subframe of the NPRS downlink subframes comprising a first PRS positioning occasion, may satisfy: <MAT> where nf is the SFN with <NUM> ≤ nf ≤ <NUM>, na is the slot number within the radio frame defined by nf with <NUM> ≤ ns ≤ <NUM>, TPRS is the PRS periodicity <NUM>, and ΔPRS is the cell-specific subframe offset <NUM>.

As shown in <FIG>, the cell-specific subframe offset ΔPRS <NUM> may be defined in terms of the number of subframes transmitted starting from SFN <NUM> ("Slot number = <NUM>," marked as slot <NUM>) to the start of the first (subsequent) PRS positioning occasion. In the example in <FIG>, the number of consecutive positioning subframes (NPRS) in each of the consecutive PRS positioning occasions 518a, 518b, and 518c equals <NUM>. Note that while NPRS may specify the number of consecutive positioning subframes per occasion, it may instead specify the number of consecutive positioning slots, based on implementation. For example, in LTE, NPRS specifies the number of consecutive positioning subframes per occasion, whereas in NR, NPRS specifies the number of consecutive positioning slots per occasion.

In some aspects, when a UE receives a PRS configuration index IPRS in the positioning assistance data for a particular cell, the UE may determine the PRS periodicity TPRS <NUM> and PRS subframe offset ΔPRS using Table <NUM>. The UE may then determine the radio frame, subframe, and slot when a PRS is scheduled in the cell (e.g., using the equation above). The positioning assistance data may be determined by, for example, the location server, and include assistance data for a reference cell, and a number of neighbor cells supported by various wireless nodes.

Typically, PRS occasions from all cells in a network that use the same frequency are aligned in time and may have a fixed known time offset (e.g., cell-specific subframe offset <NUM>) relative to other cells in the network that use a different frequency. In SFN-synchronous networks all wireless nodes (e.g., base stations) may be aligned on both frame boundary and system frame number. Therefore, in SFN-synchronous networks all cells supported by the various wireless nodes may use the same PRS configuration index IPRS for any particular frequency of PRS transmission. On the other hand, in SFN-asynchronous networks, the various wireless nodes may be aligned on a frame boundary, but not system frame number. Thus, in SFN-asynchronous networks, the PRS configuration index IPRS for each cell may be configured separately by the network so that PRS occasions align in time.

A UE may determine the timing of the PRS occasions of the reference and neighbor cells for positioning, if the UE can obtain the cell timing (e.g., SFN) of at least one of the cells, such as a reference cell or a serving cell. The timing of the other cells may then be derived by the UE based, for example, on the assumption that PRS occasions from different cells overlap.

For LTE systems, the sequence of subframes used to transmit PRS (e.g., for positioning) may be characterized and defined by a number of parameters, comprising: (i) a reserved block of bandwidth (BW), (ii) the PRS configuration index IPRS, (iii) the duration NPRS, (iv) an optional muting pattern, and (v) a muting sequence periodicity TREP that can be implicitly included as part of the muting pattern in (iv) when present. In some cases, with a fairly low PRS duty cycle, NPRS = <NUM>, TPRS = <NUM> subframes (equivalent to <NUM>), and BW = <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>. To increase the PRS duty cycle, the NPRS value can be increased to six (i.e., NPRS = <NUM>) and the bandwidth (BW) value can be increased to the system bandwidth (i.e., BW = LTE system bandwidth in the case of LTE). An expanded PRS with a larger NPRS (e.g., greater than six) and/or a shorter TPRS (e.g., less than <NUM>), up to the full duty cycle (i.e., NPRS = TPRS), may also be used in later versions of the LTE positioning protocol (LPP). A directional PRS may be configured as just described, and may, for example, use a low PRS duty cycle (e.g., NPRS = <NUM>, TPRS = <NUM> subframes) or a high duty cycle.

There are a number of cellular network-based positioning technologies, including downlink-based, uplink-based, and downlink-and-uplink-based positioning methods. Downlink-based positioning methods include observed time difference of arrival (OTDOA) in LTE, downlink time difference of arrival (DL-TDOA) in NR, and downlink angle-of-departure (DL-AoD) in NR. In an OTDOA or DL-TDOA positioning procedure, a UE measures the differences between the times of arrival (ToAs) of reference signals (e.g., PRS, TRS, NRS, CSI-RS, SSB, etc.) received from pairs of base stations, referred to as reference signal time difference (RSTD) or time difference of arrival (TDOA) measurements, and reports them to a positioning entity. More specifically, the UE receives the identifiers of a reference base station (e.g., a serving base station) and multiple non-reference base stations in assistance data. The LTE then measures the RSTD between the reference base station and each of the non-reference base stations. Based on the known locations of the involved base stations and the RSTD measurements, the positioning entity can estimate the UE's location. For DL-AoD positioning, a base station measures the angle and other channel properties (e.g., signal strength) of the downlink transmit beam used to communicate with a UE to estimate the location of the UE.

Uplink-based positioning methods include uplink time difference of arrival (UL-TDOA) and uplink angle-of-arrival (UL-AoA). UL-TDOA is similar to DL-TDOA, but is based on uplink reference signals (e.g., SRS) transmitted by the UE. For UL-AoA positioning, a base station measures the angle and other channel properties (e.g., gain level) of the uplink receive beam used to communicate with a UE to estimate the location of the UE.

Downlink-and-uplink-based positioning methods include enhanced cell-ID (E-CID) positioning and multi-round-trip-time (RTT) positioning (also referred to as "multi-cell RTT"). In an RTT procedure, an initiator (a base station or a UE) transmits an RTT measurement signal (e.g., a PRS or SRS) to a responder (a UE or base station), which transmits an RTT response signal (e.g., an SRS or PRS) back to the initiator. The RTT response signal includes the difference between the ToA of the RTT measurement signal and the transmission time of the RTT response signal, referred to as the reception-to-transmission (Rx-Tx) measurement. The initiator calculates the difference between the transmission time of the RTT measurement signal and the ToA of the RTT response signal, referred to as the "Tx-Rx" measurement. The propagation time (also referred to as the "time of flight") between the initiator and the responder can be calculated from the Tx-Rx and Rx-Tx measurements. Based on the propagation time and the known speed of light, the distance between the initiator and the responder can be determined. For multi-RTT positioning, a UE performs an RTT procedure with multiple base stations to enable its location to be triangulated based on the known locations of the base stations. RTT and multi-RTT methods can be combined with other positioning techniques, such as UL-AoA and DL-AoD, to improve location accuracy.

The E-CID positioning method is based on radio resource management (RRM) measurements. In E-CID, the UE reports the serving cell ID, the timing advance (TA), and the identifiers, estimated timing, and signal strength of detected neighbor base stations. The location of the UE is then estimated based on this information and the known locations of the base stations.

To assist positioning operations, a location server (e.g., location server <NUM>, LMF <NUM>) may provide assistance data to the UE. For example, the assistance data may include identifiers of the base stations (or the cells/TRPs of the base stations) from which to measure reference signals, the reference signal configuration parameters (e.g., the number of consecutive positioning subframes, periodicity of positioning subframes, muting sequence, frequency hopping sequence, reference signal identifier (ID), reference signal bandwidth, etc.), and/or other parameters applicable to the particular positioning method. Alternatively, the assistance data may originate directly from the base stations themselves (e.g., in periodically broadcasted overhead messages, etc.). In some cases, the UE may be able to detect neighbor network nodes itself without the use of assistance data.

A location estimate may be referred to by other names, such as a position estimate, location, position, position fix, fix, or the like. A location estimate may be geodetic and comprise coordinates (e.g., latitude, longitude, and possibly altitude) or may be civic and comprise a street address, postal address, or some other verbal description of a location. A location estimate may further be defined relative to some other known location or defined in absolute terms (e.g., using latitude, longitude, and possibly altitude). A location estimate may include an expected error or uncertainty (e.g., by including an area or volume within which the location is expected to be included with some specified or default level of confidence).

Measurement reports (e.g., RSTD, RSRP) sent by a UE for UE-assisted positioning (e.g., OTDOA, DL-TDOA, RTT, DL-AOD) are based on measurements of downlink PRS. These measurement reports are sent by the UE to the location server (e.g., location server <NUM>, LMF <NUM>, SLP <NUM>) via, for example, LPP. Specifically, the messages are sent through the base station in NAS containers that the serving base station cannot read.

A downlink PRS configuration (e.g., as illustrated in <FIG>) is independent of the UE's downlink bandwidth part (BWP). That is, the PRS resources scheduled in the time domain (e.g., symbols, slots, etc.) may span up to the cell's entire operating frequency in the frequency domain (e.g., subcarriers, PRBs, etc.). However, in the frequency domain, the UE only measures the PRS resources that fall into its active downlink BWP(s). To measure a larger PRS bandwidth, the UE needs to request one or more measurement gaps to be provided by the base station. The UE can then measure PRS (or other downlink signaling) on its other downlink BWPs during the requested measurement gap(s).

Note that BWP is a contiguous set of PRBs selected from a contiguous subset of the common RBs for a given numerology on a given carrier. Generally, a maximum of four BWPs can be specified in the downlink and uplink. That is, a UE can be configured with up to four BWPs on the downlink, and up to four BWPs on the uplink. Only one BWP (uplink or downlink) can be active at a given time, meaning the UE can only receive or transmit over one BWP at a time. On the downlink, the bandwidth of each BWP should be equal to or greater than the bandwidth of the SSB, but it may or may not contain the SSB.

In NR in unlicensed spectrum (NR-U), it may be possible for downlink PRS to be discontiguous due to the LBT (or other CCA) procedure not clearing for one or more subbands, component carriers, or BWPs (collectively referred to as subbands for simplicity) on which the PRS are to be transmitted. That is, a transmitter (e.g., a small cell base station or corresponding TRP) may only win access to a subset of the total number of subbands over which PRS are scheduled/configured to be transmitted. For example, given an <NUM> carrier with four <NUM> subbands, only a subset (one or two or three) of the subbands may clear the LBT procedure at the time at which PRS are scheduled to be transmitted, or no subband may clear. If only a subset of the subbands clear, the PRS will be transmitted over a smaller bandwidth. For example, if only two of the four <NUM> subbands clear, the PRS will be transmitted over a total of <NUM> instead of <NUM>. The smaller bandwidth may result in a lower resolution estimate of the line-of-sight (LOS) delay between the TRP and the UE, and therefore decreased positioning accuracy. If reported, the location server (e.g., location server <NUM>, LMF <NUM>, SLP <NUM>) can account for this value when computing the UE's position by post-processing the LOS delays from all the TRPs.

<FIG> is a diagram <NUM> of an exemplary scenario in which PRS are transmitted on three subbands 610a-c, according to aspects of the disclosure. In <FIG>, frequency is represented on the vertical axis and time is represented on the horizontal axis, and each block represents a scheduled transmission of PRS. In the example of <FIG>, the particular carrier frequency (e.g., an unlicensed carrier frequency) is divided into three frequency subbands 610a, 610b, and 610c. Six PRS blocks (i.e., PRS resources) per subband are scheduled during a PRS "window," or occasion, such as PRS positioning occasions <NUM> in <FIG>.

Before transmitting on any of the subbands 610a-c, the transmitter (e.g., a small cell base station or corresponding TRP in the downlink or UE in the uplink) needs to perform an LBT procedure on each of the subbands 610a-c on which it wishes to transmit. As indicated by the line at time <NUM>, it is not until after the scheduled transmission time of the second set of PRS blocks (in the time domain) that the transmitter clears (i.e., wins access to) two of the subbands (610a and 610c), at which point, it can begin transmitting PRS (as indicated by the shaded blocks) for the remainder of the PRS window/occasion. However, the transmitter does not gain access to the third subband, subband 610b, during the PRS occasion. Note that while <FIG> illustrates the transmitter clearing two subbands simultaneously, this may not always be the case. Instead, the transmitter may clear only one subband, or may wait to clear all three subbands before transmitting PRS, or may begin transmitting PRS on each subband as that subband clears. As will be appreciated, not being able to transmit across the entire scheduled bandwidth can reduce the receiver's ability to accurately measure the PRS, which can in turn reduce location estimation accuracy.

As a first solution described herein, a transmitter (e.g., base station, TRP, UE, etc.) can indicate to the location server (e.g., location server <NUM>, LMF <NUM>, SLP <NUM>) whether PRS were transmitted, and if so, the identifier(s) of the subband(s) used for transmission. This solution assumes a single transmission of PRS per window (e.g., PRS positioning occasions <NUM>), contrary to the example of <FIG>, or that the transmitter successfully won access to all subbands at the beginning of the window.

As a second solution, if the transmission consists of multiple PRS blocks (e.g., different repetitions, or having different transmission configuration indicator (TCI) states, as illustrated in <FIG>), then the transmitter can indicate to the location server the start position of PRS transmission within the PRS occasion (e.g., time <NUM>) and the identifier(s) of the subband(s) where LBT cleared (e.g., subbands 610a and 610c).

In an aspect, instead of performing LBT on a plurality of subbands (e.g., the full system bandwidth) and then transmitting PRS on a subset of the plurality of subbands (e.g., contiguous subbands that clear at the same time), the transmitter may pick and choose which subbands to test (e.g., sequentially or prefiltering via another method prior to LBT) via LBT and then, when a threshold number of subbands is reached, it can transmit PRS on all of those subbands, whether or not contiguous.

On the receiver side, the receiver (e.g., a UE, a base station/TRP/cell, etc.) can perform detection on each subband to determine whether PRS were transmitted. However, even though the receiver tunes its receiver to receive each scheduled PRS, it may not detect every PRS transmitted due to interference. Thus, as a first solution, the receiver can report the time instance(s) (e.g., slot or symbol index(es)) of PRS used for a positioning measurement. As a second solution, the receiver can report the LBT result or PRS detection result on each subband. That is, the receiver can report, for each subband, whether or not it detected PRS. Note that where the receiver is a UE, it can determine whether or not the transmitter (e.g., a serving cell/TRP) transmitted PRS on a given subband based on the channel occupancy time signaling information (COT-SI) from the transmitter, which indicates which set of subbands is active and which set of subbands is not for a particular duration of time. However, the UE generally only receives the COT-SI for the serving cell/TRP and not for neighboring cells/TRPs. As a third solution, the receiver can report the actual bandwidth used to compute the positioning measurement (e.g., RSTD value). The location server can then use the reported information to compute the actual location estimate for the UE.

In general, especially where the receiver is a UE, it may be difficult for a UE to detect the PRS transmissions from far away base stations (more specifically, TRPs and/or cells supported by the base stations), especially in unlicensed spectrum due to the effective isotropic radiated power (EIRP) and power spectrum density (PSD) limitations and no scope for power boosting. Note that for the serving cell/TRP, however, the COT-SI may signal or be used to derive the LBT status at the serving cell/TRP.

As a solution, the serving cell/TRP can signal the LBT clear status of neighbor cells/TRPs to the UE. More specifically, the serving cell/TRP can provide the identifier(s) of the subbands that the neighboring cells/TRPs were able to clear for PRS transmission. In this way, the serving cell/TRP provides a "map" of the time-frequency resources that were used by each cell/TRP for PRS transmission, which in turn improves the location estimate. The involved base stations can share this information with each other over a wired or wireless backhaul link (e.g., backhaul link <NUM>) and then transmit it to the UEs they are serving. For example, this information can be transmitted to the UE at the end of every frame during which PRS are transmitted for the UE's positioning session.

As a first sub-solution, this information can be sent to the UE in a MAC control element (MAC-CE) or in downlink control information (DCI). For example, a new MAC-CE with a different header ID could be used. For the DCI, a DCI with a new radio network temporary identifier (RNTI) (similar to an interruption RNTI (INT-RNTI) for interruption signaling) can be used. The location server can coordinate this information across the cells/TRPs in the positioning set (i.e., the set of cells/TRPs from which the UE is measuring PRS).

As a second sub-solution, the LBT clear status of neighbor cells/TRPs can be indicated within some number ("X") of slots (or microseconds) after the actual transmission of the downlink PRS and the UE can use this information to appropriately filter the downlink PRS from all the other cells/TRPs. When the UE is informed of the LBT clear status of neighbor cells/TRPs, this information can help the UE to process the positioning data (for example, PRS signals) based on the LBT clear status of neighbor cells/TRPs before the measurement report is sent to the serving cell/TRP (and then forwarded to the location server). For example, the UE can ignore the subbands without PRS transmission when processing PRS signals based on the indication. Alternatively, if the UE is estimating its own location (i.e., UE-based positioning), it does not need to forward anything to the location server.

LBT procedures may impact uplink transmission as well. Thus, for uplink transmissions, the UE can be configured to transmit in one of several modes to address the impact of performing LBT. As a first option, the UE can transmit uplink reference signals (e.g., SRS) only on contiguous subbands, even if LBT clears on additional, non-contiguous subbands. The reason to transmit only on contiguous subbands is that the peak-to-average power ratio (PAPR) is degraded when transmitting on non-contiguous subbands.

As a second option, however, the UE can transmit on non-contiguous subbands, with puncturing on the subbands where LBT does not clear. That is, the UE can generate an uplink signal to be transmitted across all of the subbands, but because certain subbands do not clear the LBT procedure, it does not transmit the generated uplink signal on those subbands. For example, with reference to <FIG>, the UE may generate an uplink signal to be transmitted over all of subbands 610a to 610c. However, because only subbands 610a and 610c clear, it punctures the portion of the uplink signal that was to be transmitted over subband 610b.

In an aspect, instead of performing LBT on a plurality of subbands (e.g., the UE's full operating bandwidth) and then transmitting PRS on a subset of the plurality of subbands (e.g., contiguous subbands that clear at the same time), the UE may pick and choose which subbands to test (e.g., sequentially or prefiltering via another method prior to LBT) via LBT and then, when a threshold number of subbands are reached, it can transmit PRS on all of those subbands, whether or not contiguous.

In an additional aspect, the UE can report the LBT result to the serving cell/TRP if there is a subsequent transmission opportunity (TxOP) before some number ("X") of microseconds after the original uplink transmission time. The serving cell/TRP can then report the list of subbands on which the UE transmitted to the location server.

Note that all of the reporting described herein can be performed on multiple carriers independently. They do not need to be combined into a single report, or fewer reports than the number of carriers. In addition, the one or more reports may include an identifier for the subset of subbands being reported, an identifier for each subband, a bitmap identifier for the subset of subbands, a start point for the first subband and a number of contiguous subbands, and any other variation.

<FIG> illustrates an exemplary method <NUM> of wireless communication, according to aspects of the disclosure. In an aspect, the method <NUM> may be performed by a transmitter device, such as any of the UEs or base stations described herein.

At <NUM>, the transmitter device performs, at a first time during a positioning session, a clear channel assessment (CCA) procedure on each of a plurality of subbands (or carriers or BWPs) in a shared spectrum frequency range. In an aspect, where the transmitter device is a UE, operation <NUM> may be performed by WWAN transceiver <NUM>, processing system <NUM>, memory component <NUM>, and/or reporting manager <NUM>, any or all of which may be considered means for performing this operation. In an aspect, where the transmitter device is a base station, operation <NUM> may be performed by WWAN transceiver <NUM>, processing system <NUM>, memory component <NUM>, and/or reporting manager <NUM>, any or all of which may be considered means for performing this operation.

At <NUM>, the transmitter device transmits, at a second time during the positioning session, positioning reference signals on a subset of subbands of the plurality of subbands that cleared the CCA procedure. In an aspect, where the transmitter device is a UE, operation <NUM> may be performed by WWAN transceiver <NUM>, processing system <NUM>, memory component <NUM>, and/or reporting manager <NUM>, any or all of which may be considered means for performing this operation. In an aspect, where the transmitter device is a base station, operation <NUM> may be performed by WWAN transceiver <NUM>, processing system <NUM>, memory component <NUM>, and/or reporting manager <NUM>, any or all of which may be considered means for performing this operation.

At <NUM>, the transmitter device optionally transmits, to a positioning entity (e.g., location server <NUM>, LMF <NUM>, SLP <NUM>, or a UE for UE-based positioning), a report including an identifier of each of the subset of subbands. In an aspect, where the transmitter device is a UE, operation <NUM> may be performed by WWAN transceiver <NUM>, processing system <NUM>, memory component <NUM>, and/or reporting manager <NUM>, any or all of which may be considered means for performing this operation. In an aspect, where the transmitter device is a base station, operation <NUM> may be performed by WWAN transceiver <NUM>, processing system <NUM>, memory component <NUM>, and/or reporting manager <NUM>, any or all of which may be considered means for performing this operation.

The various illustrative logical blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein.

The methods, sequences and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in random access memory (RAM), flash memory, read-only memory (ROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. The ASIC may reside in a user terminal (e.g., UE).

In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.

Claim 1:
A method of wireless communication performed by a transmitter device, comprising:
performing (<NUM>), at a first time during a positioning session, a clear channel assessment, CCA, procedure on each of a plurality of subbands in a shared spectrum frequency range;
transmitting (<NUM>), at a second time during the positioning session, positioning reference signals on a subset of subbands of the plurality of subbands that cleared the CCA procedure; and
transmitting (<NUM>), to a positioning entity, one or more reports including identifiers of each subband in the subset of subbands that cleared the CCA procedure.