Orthogonal Random Access Channel (RACH) Preamble Sequences for Positioning

Abstract

In one aspect, a user equipment (UE) determines at least one random access channel (RACH) preamble from a first set of RACH preambles, the first set of RACH preambles being for positioning purposes and a second set of RACH preambles being for communication purposes, the first set of RACH preambles and the second set of RACH preambles being associated with at least one transmit reception point (TRP), transmits the at least one RACH preamble to the at least one TRP to indicate that the UE will engage in a positioning session, receives from the at least one TRP an allocation of one or more resources for transmission of an uplink positioning signal for the positioning session in response to the transmission of the at least one RACH preamble, and transmits the uplink positioning signal via the one or more resources.

Description

[Technical Field]

[0001] Aspects of the present disclosure relate generally to wireless communications. [Background technology]

[0002] Wireless communication systems have evolved through various generations, including first-generation analog wireless telephone service (1G), second-generation (2G) digital wireless telephone service (including interim 2.5G and 2.75G networks), third-generation (3G) high-speed data, Internet-enabled wireless service, and fourth-generation (4G) service (e.g., Long Term Evolution (LTE) or WiMax). Currently, there are many different types of wireless communication systems in use, including cellular systems and personal communications services (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), Global System for Mobile Communications (GSM), etc.

[0003] The fifth-generation (5G) wireless standard, known as New Radio (NR), promises higher data rates, more connections, and better coverage, among other improvements. According to the Next Generation Mobile Network Alliance, the 5G standard is designed to provide data rates of tens of megabits per second to each of tens of thousands of users, delivering 1 gigabit per second to dozens of workers on an office floor. To support large-scale sensor deployments, hundreds of thousands of simultaneous connections should be supported. Therefore, the spectral efficiency of 5G mobile communications should be significantly enhanced compared to the current 4G standard. Furthermore, signaling efficiency should be enhanced and latency significantly reduced compared to current standards. Summary of the Invention [Means for solving the problem]

[0004] The following presents a simplified summary related to one or more aspects disclosed herein. As such, the following summary is not intended to be an extensive overview related to all contemplated aspects, nor is it intended to identify key or critical elements related to all contemplated aspects or to delineate the scope related to any particular aspect. As such, the following summary has the sole purpose of presenting some concepts related to one or more aspects related to the mechanisms disclosed herein in a simplified form prior to the detailed description presented below.

[0005] In one aspect, a method of wireless communication performed by a user equipment (UE) includes determining at least one random access channel (RACH) preamble from a first set of RACH preambles, the first set of RACH preambles being for positioning purposes and a second set of RACH preambles being for communication purposes, the first set of RACH preambles and the second set of RACH preambles being associated with at least one transmission-reception point (TRP); transmitting the at least one RACH preamble to the at least one TRP to indicate that the UE is involved in a positioning session; receiving, in response to transmitting the at least one RACH preamble, allocation of one or more resources from the at least one TRP for transmission of uplink positioning signals for the positioning session; and transmitting the uplink positioning signals via the one or more resources.

[0006] In one aspect, a method of wireless communication performed by a TRP includes transmitting an indication of at least one RACH preamble of a first set of RACH preambles, where the first set of RACH preambles is for positioning purposes and a second set of RACH preambles is for communication purposes, where the first set of RACH preambles and the second set of RACH preambles are associated with the TRP; receiving at least one RACH preamble from a UE from the first set of RACH preambles; and transmitting, in response to receiving the at least one RACH preamble, an allocation of one or more resources to the UE for transmission of uplink positioning signals for a positioning session involving the UE.

[0007] In one aspect, a UE includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to: determine at least one RACH preamble from a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes and a second set of RACH preambles is for communication purposes, wherein the first set of RACH preambles and the second set of RACH preambles are associated with at least one TRP; cause the at least one transceiver to transmit the at least one RACH preamble to the at least one TRP to indicate that the UE is involved in a positioning session; receive, in response to transmitting the at least one RACH preamble, from the at least one TRP, allocation of one or more resources for transmission of uplink positioning signals for the positioning session; and cause the at least one transceiver to transmit the uplink positioning signals via the one or more resources.

[0008] In one aspect, the TRP includes a memory, at least one transceiver, and at least one processor communicatively coupled to the memory and the at least one transceiver, wherein the at least one processor is configured to: cause the at least one transceiver to transmit an indication of at least one RACH preamble of a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes and the second set of RACH preambles is for communication purposes, wherein the first set of RACH preambles and the second set of RACH preambles are associated with the TRP; receive from the UE the at least one RACH preamble from the first set of RACH preambles; and cause the at least one transceiver to transmit to the UE, in response to receiving the at least one RACH preamble, an allocation of one or more resources for transmission of an uplink positioning signal for a positioning session involving the UE.

[0009] In one aspect, a UE includes means for determining at least one RACH preamble from a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes and the second set of RACH preambles is for communication purposes, and the first set of RACH preambles and the second set of RACH preambles are associated with at least one TRP; means for transmitting the at least one RACH preamble to the at least one TRP to indicate that the UE is involved in a positioning session; means for receiving, in response to transmitting the at least one RACH preamble, from the at least one TRP, allocation of one or more resources for transmission of uplink positioning signals for the positioning session; and means for transmitting the uplink positioning signals via the one or more resources.

[0010] In one aspect, the TRP includes means for transmitting an indication of at least one RACH preamble of a first set of RACH preambles, where the first set of RACH preambles is for positioning purposes and the second set of RACH preambles is for communication purposes, where the first set of RACH preambles and the second set of RACH preambles are associated with the TRP; means for receiving at least one RACH preamble from the first set of RACH preambles; and means for transmitting to the UE, in response to receiving the at least one RACH preamble, an allocation of one or more resources for transmission of uplink positioning signals for a positioning session involving the UE.

[0011] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions includes computer-executable instructions comprising: at least one instruction to instruct a UE to determine at least one RACH preamble from a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes and a second set of RACH preambles is for communication purposes, and wherein the first set of RACH preambles and the second set of RACH preambles are associated with at least one TRP; at least one instruction to instruct the UE to transmit the at least one RACH preamble to the at least one TRP to indicate that the UE is involved in a positioning session; at least one instruction to instruct the UE to receive, in response to the transmission of the at least one RACH preamble, from the at least one TRP, an allocation of one or more resources for transmission of uplink positioning signals for the positioning session; and at least one instruction to instruct the UE to transmit the uplink positioning signals via the one or more resources.

[0012] In one aspect, a non-transitory computer-readable medium storing computer-executable instructions includes computer-executable instructions comprising: at least one instruction to instruct a TRP to transmit an indication of at least one RACH preamble of a first set of RACH preambles, where the first set of RACH preambles is for positioning purposes and the second set of RACH preambles is for communication purposes, and where the first set of RACH preambles and the second set of RACH preambles are associated with the TRP; at least one instruction to instruct the TRP to receive at least one RACH preamble from the first set of RACH preambles from a UE; and at least one instruction to instruct the TRP to transmit, in response to receiving the at least one RACH preamble, an allocation of one or more resources to the UE for transmission of uplink positioning signals for a positioning session involving the UE.

[0013] Other objects and advantages associated with the embodiments disclosed herein will become apparent to those skilled in the art based on the accompanying drawings and detailed description.

[0014] The accompanying drawings are presented to aid in the explanation of various aspects of the present disclosure and are provided solely for the purpose of illustrating the aspects and not for the purpose of limiting the aspects. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 illustrates an exemplary wireless communication system according to aspects of the present disclosure. [Figure 2A] FIG. 1 illustrates an exemplary wireless network structure according to aspects of the present disclosure. [Figure 2B] FIG. 1 illustrates an exemplary wireless network structure according to aspects of the present disclosure. [Figure 3A] 1 is a simplified block diagram of several sample aspects of components that may be employed in a user equipment (UE) and configured to support communication as taught herein; [Figure 3B]1 is a simplified block diagram of several sample aspects of components that may be employed in a base station and configured to support communication as taught herein; [Figure 3C] 1 is a simplified block diagram of several sample aspects of components that may be employed in a network entity and configured to support communications as taught herein; [Figure 4A] FIG. 2 illustrates an exemplary frame structure according to aspects of the present disclosure. [Figure 4B] FIG. 1 illustrates an example channel within a frame structure according to an aspect of the present disclosure. [Figure 4C] FIG. 2 illustrates an exemplary frame structure according to aspects of the present disclosure. [Figure 4D] FIG. 1 illustrates an example channel within a frame structure according to an aspect of the present disclosure. [Figure 5] FIG. 1 illustrates an example random access procedure according to an aspect of the present disclosure. [Figure 6] FIG. 1 illustrates an example random access procedure according to an aspect of the present disclosure. [Figure 7] FIG. 1 illustrates an example random access procedure according to an aspect of the present disclosure. [Figure 8] FIG. 1 illustrates various radio resource control (RRC) states available in New Radio (NR), according to aspects of the present disclosure. [Figure 9] FIG. 1 is a diagram of an example RACH preamble according to an aspect of the present disclosure. [Figure 10] 1 is a graph showing various preamble lengths and formats in NR. [Figure 11] FIG. 1 illustrates an example random access procedure according to an aspect of the present disclosure. [Figure 12] FIG. 1 illustrates an example random access procedure according to an aspect of the present disclosure. [Figure 13] FIG. 1 illustrates an example random access procedure according to an aspect of the present disclosure. [Figure 14] FIG. 1 illustrates an exemplary method of wireless communication according to an aspect of the present disclosure. [Figure 15] FIG. 1 illustrates an exemplary method of wireless communication according to an aspect of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] Aspects of the present disclosure are provided in the following description and related drawings, directed to various examples provided for illustrative purposes. Alternative aspects may be devised without departing from the scope of the present disclosure. Additionally, well-known elements of the present disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the present disclosure.

[0017] The words "exemplary" and / or "example" are used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" and / or "example" is not necessarily to be construed as preferred or advantageous over other aspects. Likewise, the term "aspects of the present disclosure" does not require that all aspects of the present disclosure include the discussed feature, advantage or mode of operation.

[0018] Those skilled in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the following description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the particular application, in part on the desired design, in part on the corresponding technology, etc.

[0019] Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that the various actions described herein may be performed by specific circuitry (e.g., an application-specific integrated circuit (ASIC)), by program instructions executed by one or more processors, or a combination of both. Additionally, the sequences of actions described herein may be considered to be embodied entirely in any form of non-transitory computer-readable storage medium storing a corresponding set of computer instructions that, when executed, cause or instruct the associated processor(s) of the device to perform the functionality described herein. Accordingly, various aspects of the present disclosure may be embodied in a number of different forms, all of which are contemplated to be within the scope of the claimed subject matter. Additionally, for each aspect described herein, the corresponding form of any such aspect may be described herein, for example, as “logic configured to” perform the described actions.

[0020] The terms “user equipment” (UE) and “base station,” as used herein, are not intended to be specific to or otherwise limited to any particular radio access technology (RAT) unless otherwise specified. In general, a UE may be any wireless communication device (e.g., a mobile phone, a router, a tablet computer, a laptop computer, a consumer asset tracking device, a wearable (e.g., a smart watch, smart glasses, an augmented reality (AR) / virtual reality (VR) headset, etc.), a vehicle (e.g., an automobile, a motorcycle, a bicycle, etc.), an Internet of Things (IoT) device, etc.) used by a user to communicate over a wireless communication network. A UE may be mobile or may be stationary (e.g., at some times) 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, a UE can communicate with a core network via a RAN, through which the UE can be connected to external networks such as the Internet and to other UEs. Of course, other mechanisms for connecting to the core network and / or the Internet are also possible for a UE, such as via a wired access network, a wireless local area network (WLAN) network (e.g., based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 specifications, etc.), etc.

[0021] A base station may operate according to one of several RATs with which it communicates with the UE, depending on the network in which the UE is deployed, and may alternatively be referred to as an access point (AP), network node, Node B, evolved Node B (eNB), next-generation eNB (ng-eNB), New Radio (NR) Node B (also referred to as gNB or gNode B), etc. Base stations may be used primarily to support wireless access by UEs, including supporting data, voice, and / or signaling connections for supported UEs. In some systems, base stations may provide purely edge node signaling functionality, while in other systems, base stations may provide additional control and / or network management functions. A communication link through which a UE 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 a base station can send signals to a UE is called a downlink (DL) channel or a 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 traffic channel or a downlink / forward traffic channel.

[0022] The term "base station" can refer to a single physical transmit / receive point (TRP) or multiple physical TRPs, which may or may not be collocated. For example, when the term "base station" refers to a single physical TRP, the physical TRP may be an antenna of the base station corresponding to the base station's cell (or several cell sectors). When the term "base station" refers to multiple collocated physical TRPs, the physical TRPs may be an array of antennas of the base station (e.g., as in a multiple-input multiple-output (MIMO) system or when the base station employs beamforming). When the term "base station" refers to multiple non-collocated 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, a non-collocated physical TRP may be a serving base station that receives measurement reports from the UE and neighboring base stations whose reference RF signals the UE is measuring. A TRP is a point from which a base station transmits and receives wireless signals, and therefore, as used herein, references to transmission from or reception at a base station should be understood as references to the particular TRP of the base station.

[0023] In some implementations that support positioning of UEs, a base station may not support wireless access by the UE (e.g., may not support a data connection, a voice connection, and / or a signaling connection for the UE), but instead may transmit reference signals to the UE to be measured by the UE and / or may receive and measure signals transmitted by the UE. Such a base station may be referred to as a positioning beacon (e.g., when transmitting signals to the UE) and / or a location measurement unit (e.g., when receiving and measuring signals from the UE).

[0024] An "RF signal" comprises electromagnetic waves of a given frequency that transport information through 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, due to the propagation characteristics of RF signals through a multipath channel, the receiver may receive multiple "RF signals" corresponding to each transmitted RF signal. The same transmitted RF signal over different paths between the transmitter and receiver is sometimes referred to as a "multipath" RF signal.

[0025] 1 illustrates an exemplary wireless communication system 100. The wireless communication system 100 (sometimes referred to as a wireless wide area network (WWAN)) may include various base stations 102 and various UEs 104. The base stations 102 may include macrocell base stations (high-power cellular base stations) and / or small cell base stations (low-power cellular base stations). In one aspect, the macrocell base stations may include eNBs and / or ng-eNBs, where the wireless communication system 100 corresponds to an LTE network, or gNBs, where the wireless communication system 100 corresponds to an NR network, or a combination of both, and the small cell base stations may include femtocells, picocells, microcells, etc.

[0026] The base stations 102 may collectively form a RAN and may interface with a core network 170 (e.g., Evolved Packet Core (EPC) or 5G Core (5GC)) through backhaul links 122 and to one or more location servers 172 (which may be part of the core network 170 or may be external to the core network 170) through the core network 170. In addition to other functions, the base stations 102 may perform functions related to one or more of forwarding user data, radio channel encryption and decryption, 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 services (MBMS), subscriber and equipment tracing, RAN information management (RIM), paging, positioning, and distribution of alert messages. The base stations 102 may communicate with each other directly or indirectly (e.g., through EPC / 5GC) via backhaul links 134, which may be wired or wireless.

[0027] The base stations 102 may communicate wirelessly with the UEs 104. Each of the base stations 102 may provide communication coverage for a respective geographic coverage area 110. In an aspect, one or more cells may be supported by the base station 102 in each coverage area 110. A “cell” is a logical communication entity used for communication with a base station (e.g., over some frequency resources referred to as a carrier frequency, component carrier, carrier, band, etc.) and may be associated with an identifier (e.g., a physical cell identifier (PCI), a virtual cell identifier (VCI), a cell global identifier (CGI)) to distinguish between cells operating over the same or different carrier frequencies. 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 to different types of UEs. Because a cell is supported by a particular base station, the term “cell” can refer to one or both of the logical communication entity and its supporting base station, depending on the context. In some cases, the term "cell" may refer to the geographic coverage area (e.g., sector) of a base station, so long as the carrier frequency can be detected and used for communication within some portion of the geographic coverage area 110.

[0028] While adjacent to macrocell base stations 102, the geographic coverage areas 110 may partially overlap (e.g., within handover regions), and some of the geographic coverage areas 110 may be significantly overlapped by larger geographic coverage areas 110. For example, a small cell base station 102' may have a coverage area 110' that significantly overlaps with the coverage area 110 of one or more macrocell base stations 102. A network including both small cell base stations and macrocell base stations may be referred to as a heterogeneous network. A heterogeneous network may also include Home eNBs (HeNBs) that may serve restricted groups called closed subscriber groups (CSGs).

[0029] The communication link 120 between the base station 102 and the UE 104 may include uplink (also called reverse link) transmissions from the UE 104 to the base station 102, and / or downlink (also called forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use MIMO antenna techniques, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link 120 may be over one or more carrier frequencies. The allocation of carriers may be asymmetric for the downlink and uplink (e.g., more or fewer carriers may be allocated for the downlink than for the uplink).

[0030] The wireless communication system 100 may further include a wireless local area network (WLAN) access point (AP) 150 communicating with a WLAN station (STA) 152 via a communication link 154 in an unlicensed frequency spectrum (e.g., 5 GHz). When communicating in the unlicensed frequency spectrum, the WLAN STA 152 and / or the WLAN AP 150 may perform a clear channel assessment (CCA) or listen-before-talk (LBT) procedure before communicating to determine whether a channel is available.

[0031] The small cell base station 102' may operate in a licensed and / or unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell base station 102' may employ LTE or NR technology and may use the same 5 GHz unlicensed frequency spectrum used by the WLAN AP 150. A small cell base station 102' employing LTE / 5G in an unlicensed frequency spectrum may extend coverage to and / or increase the capacity of an access network. NR in an unlicensed spectrum may be referred to as NR-U. LTE in an unlicensed spectrum may be referred to as LTE-U, licensed assisted access (LAA), or MultiFire.

[0032] The wireless communication system 100 may further include a millimeter-wave (mmW) base station 180 in communication with the UE 182 and capable of operating within mmW and / or quasi-mmW frequencies. Extremely high frequency (EHF) is the RF portion of the electromagnetic spectrum. EHF ranges from 30 GHz to 300 GHz and has wavelengths between 1 and 10 millimeters. Radio waves in this band are sometimes referred to as millimeter waves. Sub-mmW may extend down to frequencies of 3 GHz, with wavelengths of 100 millimeters. The very high frequency (SHF) band extends between 3 GHz and 30 GHz, also known as centimeter waves. Communications using the mmW / quasi-mmW radio frequency bands have high path loss and relatively short distances. The mmW base station 180 and the UE 182 may utilize beamforming (transmit and / or receive) over the mmW communication link 184 to compensate for the significant path loss and short distances. It will be appreciated that in alternative configurations, one or more base stations 102 may also transmit using mmW or quasi-mmW and beamforming. Therefore, it will be appreciated that the above illustrations are merely exemplary and should not be construed as limiting the various aspects disclosed herein.

[0033] Transmit beamforming is a technique for focusing an RF signal in a particular direction. Traditionally, when a network node (e.g., a base station) broadcasts an RF signal, it broadcasts the signal in all directions (omnidirectionally). With transmit beamforming, the network node determines where a given target device (e.g., UE) is located (relative to the transmitting network node) and projects a stronger downlink RF signal in that particular direction, thereby providing a faster and more powerful RF signal (in terms of data rate) to the receiving device. To change the directionality of the RF signal when transmitting, the network node can control the phase and relative amplitude of the RF signal at each of one or more transmitters broadcasting the RF signal. For example, the network node may use an array of antennas (called a “phased array” or “antenna array”) that creates a beam of RF waves that can be “steered” to points in different directions without actually moving the antennas. Specifically, RF currents from the transmitter are fed to individual antennas with the appropriate phase relationship so that the radio waves from the separate antennas add together to enhance radiation in desired directions while suppressing or eliminating radiation in undesired directions.

[0034] A transmit beam may be quasi-colocated, meaning that the transmit beam appears to a receiver (e.g., a UE) to have the same parameters regardless of whether the network node's own transmit antennas are physically colocated. In NR, there are four types of quasi-colocation (QCL) relationships. In particular, a given type of QCL relationship means that some parameters for a target reference RF signal on a target beam can be derived from information about a source reference RF signal on a source beam. If the source reference RF signal is QCL Type A, the receiver can use the source reference RF signal to estimate the Doppler shift, Doppler spread, mean delay, and delay spread of the target reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type B, the receiver can use the source reference RF signal to estimate the Doppler shift and Doppler spread of the target reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type C, the receiver can use the source reference RF signal to estimate the Doppler shift and mean delay of the target reference RF signal transmitted on the same channel. If the source reference RF signal is QCL Type D, the receiver can use the source reference RF signal to estimate spatial reception parameters of a target reference RF signal transmitted on the same channel.

[0035] In receive beamforming, a receiver uses receive beams to amplify RF signals detected on a given channel. For example, the receiver can increase the gain setting and / or adjust the phase setting of an antenna array in a particular direction to amplify (e.g., increase the gain level of) RF signals received from that direction. Thus, when a receiver is said to beamform in a direction, it means that the beam gain in that direction is greater than the beam gains along other directions, or that the beam gain in that direction is greatest compared to the beam gains in that direction of all other receive beams available to the receiver. This results in a stronger received signal strength (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) of RF signals received from that direction.

[0036] The receive beams may be spatially related. Spatial relationship means that parameters for a transmit beam for a second reference signal may be derived from information about the receive beam for the first reference signal. For example, a UE may use a particular receive beam to receive one or more reference downlink reference signals (e.g., a positioning reference signal (PRS), a tracking reference signal (TRS), a phase tracking reference signal (PTRS), a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a synchronization signal block (SSB), etc.) from a base station. The UE can then form a transmit beam for sending one or more uplink reference signals (e.g., an uplink positioning reference signal (UL-PRS), a sounding reference signal (SRS), a demodulation reference signal (DMRS), a PTRS, etc.) to that base station based on the parameters of the receive beam.

[0037] Note that a "downlink" beam may be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if a base station forms a downlink beam to transmit a reference signal to a UE, the downlink beam is a transmit beam. However, if the UE forms a downlink beam, the downlink beam is a receive beam for receiving a downlink reference signal. Similarly, an "uplink" beam may be either a transmit beam or a receive beam, depending on the entity that forms it. For example, if a base station forms an uplink beam, the uplink beam is an uplink receive beam, and if the UE forms an uplink beam, the uplink beam is an uplink transmit beam.

[0038] In 5G, the frequency spectrum in which wireless nodes (e.g., base station 102 / 180, UE 104 / 182) operate is divided into multiple frequency ranges: FR1 (450 MHz to 6000 MHz), FR2 (24250 MHz to 52600 MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In a multi-carrier system such as 5G, one of the carrier frequencies is called the “primary carrier” or “anchor carrier” or “primary serving cell” or “PCell,” and the remaining carrier frequencies are called “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 the UE 104 / 182 and the cell on which the UE 104 / 182 either performs an initial radio resource control (RRC) connection establishment procedure or initiates an RRC connection re-establishment procedure. The primary carrier carries all common and UE-specific control channels and may be a carrier among licensed frequencies (although this is not always the case). The secondary carrier is a carrier operating on a second frequency (e.g., FR2) that may be configured once an RRC connection is established between the UE 104 and the anchor carrier and may be used to provide additional radio resources. In some cases, the secondary carrier may be a carrier among unlicensed frequencies. Because both the primary uplink carrier and the primary downlink carrier are typically UE-specific, the secondary carrier may contain only necessary signaling information and signals; for example, UE-specific signaling information and signals may not be present in the secondary carrier. This means that different UEs 104 / 182 in a cell may have different downlink primary carriers. The same is true for the uplink primary carrier. The network can change the primary carrier of any UE 104 / 182 at any time. This is done, for example, to balance the load on different carriers.Since a "serving cell" (whether PCell or SCell) corresponds to a carrier frequency / component carrier over which several base stations are communicating, terms such as "cell," "serving cell," "component carrier," and "carrier frequency" may be used interchangeably.

[0039] For example, still referring to FIG. 1 , one of the frequencies utilized by the macrocell base station 102 may be an anchor carrier (i.e., “PCell”), and other frequencies utilized by the macrocell base station 102 and / or the mmW base station 180 may be secondary carriers (“SCells”). Simultaneous transmission and / or reception of multiple carriers allows the UE 104 / 182 to significantly increase its data transmission and / or data reception rates. For example, two aggregated 20 MHz carriers in a multi-carrier system would theoretically lead to a two-fold increase in data rate (i.e., 40 MHz) compared to that achieved with a single 20 MHz carrier.

[0040] Wireless communications system 100 may further include a UE 164, which may communicate with macrocell base station 102 via communications link 120 and / or with mmW base station 180 via mmW communications link 184. For example, macrocell base station 102 may support a PCell and one or more SCells for UE 164, and mmW base station 180 may support one or more SCells for UE 164.

[0041] In the example of FIG. 1 , one or more Earth-orbiting satellite positioning system (SPS) space vehicles (SVs) 112 (e.g., satellites) may be used as independent sources of location information for any of the illustrated UEs (shown in FIG. 1 as a single UE 104 for simplicity). The UE 104 may include one or more dedicated SPS receivers specifically designed to receive signals for deriving geolocation information from the SVs 112. An SPS typically includes a system of transmitters (e.g., SVs 112) positioned to enable receivers (e.g., UEs 104) to determine their location on or above the Earth based at least in part on signals received from the transmitters. Such transmitters typically transmit signals marked with a repeating pseudorandom noise (PN) code with a set number of chips. While typically located within the SVs 112, transmitters may sometimes be located on ground-based control stations, base stations 102, and / or other UEs 104.

[0042] The use of SPS signals may be augmented by various satellite-based augmentation systems (SBAS), which may be associated with or otherwise enabled for use with one or more global and / or regional navigation satellite systems. For example, SBAS may include augmentation systems that provide integrity information, differential corrections, and the like, such as the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay Service (EGNOS), the Multifunction Satellite Augmentation System (MSAS), the Global Positioning System (GPS)-Aided Geo-Augmented Navigation, or the GPS and Geo-Augmented Navigation System (GAGAN). Thus, as used herein, SPS may include any combination of one or more global and / or regional navigation satellite systems and / or augmentation systems, and SPS signals may include SPS, SPS-like signals, and / or other signals associated with such one or more SPSs.

[0043] The wireless communication system 100 may further include one or more UEs, such as a UE 190, that indirectly connect to one or more communication networks via one or more device-to-device (D2D) peer-to-peer (P2P) links (referred to as “sidelinks”). In the example of FIG. 1, the UE 190 has a D2D P2P link 192 with one of the UEs 104 connected to one of the base stations 102 (e.g., through which the UE 190 may indirectly obtain cellular connectivity), and a D2D P2P link 194 with a WLAN STA 152 connected to a WLAN AP 150 (through which the UE 190 may indirectly obtain WLAN-based Internet connectivity). In one example, the D2D P2P links 192 and 194 may be supported using any well-known D2D RAT, such as LTE Direct (LTE-D), WiFi Direct (WiFi-D), Bluetooth®, etc.

[0044] 2A shows an exemplary wireless network structure 200. For example, a 5GC 210 (also referred to as a Next Generation Core (NGC)) can be viewed functionally as a control plane function 214 (e.g., UE registration, authentication, network access, gateway selection, etc.) and a user plane function 212 (e.g., UE gateway function, access to data network, IP routing, etc.), which operate cooperatively to form a core network. A user plane interface (NG-U) 213 and a control plane interface (NG-C) 215 connect a gNB 222 to the 5GC 210, specifically to the control plane function 214 and the user plane function 212. In an additional configuration, an ng-eNB 224 may also be connected to the 5GC 210 via the NG-C 215 to the control plane function 214 and the NG-U 213 to the user plane function 212. Additionally, the ng-eNB 224 may communicate directly with the gNB 222 via a backhaul connection 223. In some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both the ng-eNB 224 and the gNB 222. Either the gNB 222 or the ng-eNB 224 may be in communication with the UE 204 (e.g., any of the UEs shown in FIG. 1). Another optional aspect may include a location server 230, which may be in communication with the 5GC 210 to provide location assistance to the UE 204. The location servers 230 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively, each may correspond to a single server. The location server 230 may be configured to support one or more location services for the UE 204 that can connect to the location server 230 via the core network 5GC 210 and / or via the Internet (not shown). Furthermore, the location server 230 may be integrated into a component of the core network, or alternatively, may be external to the core network.

[0045] 2B shows another exemplary wireless network structure 250. For example, the 5GC 260 may be viewed functionally as a control plane function provided by an access and mobility management function (AMF) 264 and a user plane function provided by a user plane function (UPF) 262, operating cooperatively to form a core network (i.e., the 5GC 260). A user plane interface 263 and a control plane interface 265 connect the ng-eNB 224 to the 5GC 260, specifically to the UPF 262 and the AMF 264, respectively. In an additional configuration, the gNB 222 may also be connected to the 5GC 260 via the control plane interface 265 to the AMF 264 and the user plane interface 263 to the UPF 262. Furthermore, the ng-eNB 224 may communicate directly with the gNB 222 via the backhaul connection 223, with or without gNB direct connectivity to the 5GC 260. In some configurations, the new RAN 220 may have only one or more gNBs 222, while other configurations include one or more of both the ng-eNB 224 and the gNB 222. Either the gNB 222 or the ng-eNB 224 may communicate with the UE 204 (e.g., any of the UEs shown in FIG. 1). The base stations of the new RAN 220 communicate with the AMF 264 via an N2 interface and with the UPF 262 via an N3 interface.

[0046] The AMF 264 functions include registration management, connection management, reachability management, mobility management, lawful intercept, transport for session management (SM) messages between the UE 204 and a session management function (SMF) 266, a transparent proxy service for routing SM messages, access authentication and access authorization, transport for short message service (SMS) messages between the UE 204 and a short message service function (SMSF) (not shown), and a security anchor functionality (SEAF). The AMF 264 also interacts with an authentication server function (AUSF) (not shown) and the UE 204 to receive intermediate keys established as a result of the UE 204 authentication process. In the case of UMTS (Universal Mobile Telecommunications System) subscriber identity module (USIM)-based authentication, the AMF 264 retrieves security material from the AUSF. The AMF 264 functions also include security context management (SCM). The SCM receives keys from the SEAF that the SCM uses to derive access network-specific keys. The functionality of the AMF 264 also includes location service management for regulated services, transport for location service messages between the UE 204 and the Location Management Function (LMF) 270 (acting as the location server 230), transport for location service messages between the New RAN 220 and the LMF 270, Evolved Packet System (EPS) bearer identifier allocation for interworking with EPS, and UE 204 mobility event notification. In addition, the AMF 164 also supports functionality for non-3GPP (Third Generation Partnership Project) access networks.

[0047] The functions of the UPF 262 include acting as an anchor point for intra-RAT / inter-RAT mobility (when applicable), acting as an outer protocol data unit (PDU) session point for interconnection to a data network (not shown), routing and forwarding packets, 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) processing for the user plane (e.g., uplink / downlink rate enforcement, reflective QoS marking in the downlink), uplink traffic validation (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 one or more "end markers" to the source RAN node. The UPF 262 may also support the transfer of location service messages over the user plane between the UE 204 and a location server such as the Secure User Plane Localization (SUPL) Location Platform (SLP) 272.

[0048] The functions of the SMF 266 include session management, UE Internet Protocol (IP) address allocation and management, selection and control of user plane functions, configuration of traffic steering in the UPF 262 to route traffic to the appropriate destination, control of policy enforcement and part of QoS, and downlink data notification. The interface through which the SMF 266 communicates with the AMF 264 is called the N11 interface.

[0049] Another optional aspect may include an LMF 270, which may be in communication with the 5GC 260 to provide location assistance to the UE 204. The LMF 270 may be implemented as multiple separate servers (e.g., physically separate servers, different software modules on a single server, different software modules spread across multiple physical servers, etc.), or alternatively, each may correspond to a single server. The LMF 270 may be configured to support one or more location services for UEs 204 that can connect to the LMF 270 via the core network 5GC 260 and / or via the Internet (not shown). The SLP 272 may support similar functions as the LMF 270, while the LMF 270 may communicate with the AMF 264, the new RAN 220, and the UE 204 via the control plane (e.g., using interfaces and protocols intended to convey signaling messages rather than voice or data), and the SLP 270 may communicate with the UE 204 and external clients (not shown in FIG. 2B) via the user plane (e.g., using protocols intended to carry voice and / or data, such as Transmission Control Protocol (TCP) and / or IP).

[0050] 3A, 3B, and 3C illustrate several example components (represented by corresponding blocks) that may be incorporated within a UE 302 (which may correspond to any of the UEs described herein), a base station 304 (which may correspond to any of the base stations described herein), and a network entity 306 (which may correspond to or embody any of the network functions described herein, including location server 230 and LMF 270) to support file transmission operations as taught herein. It will be appreciated that these components may be implemented in different types of devices in different implementations (e.g., in an ASIC, in a system-on-chip (SoC), etc.). The illustrated components may also be incorporated into other devices in a communication system. For example, other devices in the system may include components similar to the illustrated components to provide similar functionality. Also, a given device may include one or more of the components. For example, a device may include multiple transceiver components that enable the device to operate on multiple carriers and / or communicate via different technologies.

[0051] The UE 302 and base station 304 each include a wireless wide area network (WWAN) transceiver 310 and 350, respectively, that provides means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc.) over one or more wireless communications networks (not shown), such as an NR network, an LTE network, a GSM network, etc. The WWAN transceivers 310 and 350 may be connected to one or more antennas 316 and 356, respectively, for communicating with other network nodes, such as other UEs, access points, base stations (e.g., eNBs, gNBs), etc., via at least one designated RAT (e.g., NR, LTE, GSM, etc.) over a wireless communications medium of interest (e.g., some set of time / frequency resources within a particular frequency spectrum). The WWAN transceivers 310 and 350 may be variously configured to transmit and encode signals 318 and 358 (e.g., messages, instructions, information, etc.), respectively, and conversely, to receive and decode signals 318 and 358 (e.g., messages, instructions, information, pilots, etc.), respectively, in accordance with a designated RAT. In particular, the WWAN transceivers 310 and 350 include one or more transmitters 314 and 354, respectively, for transmitting and encoding signals 318 and 358, respectively, and one or more receivers 312 and 352, respectively, for receiving and decoding signals 318 and 358, respectively.

[0052] The UE 302 and base station 304 also, at least in some cases, include wireless local area network (WLAN) transceivers 320 and 360, respectively. The WLAN transceivers 320 and 360 may be connected to one or more antennas 326 and 366, respectively, and may provide means for communicating (e.g., means for transmitting, means for receiving, means for measuring, means for tuning, means for refraining from transmitting, etc.) 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 target wireless communications medium. The WLAN transceivers 320 and 360 may be variously configured to transmit and encode signals 328 and 368, respectively (e.g., messages, instructions, information, etc.), and conversely, to receive and decode signals 328 and 368, respectively (e.g., messages, instructions, information, pilots, etc.), in accordance with the designated RAT. In particular, WLAN transceivers 320 and 360 include one or more transmitters 324 and 364, respectively, for transmitting and encoding signals 328 and 368, respectively, and one or more receivers 322 and 362, respectively, for receiving and decoding signals 328 and 368, respectively.

[0053] Transceiver circuitry including at least one transmitter and at least one receiver may in some implementations comprise an integrated device (e.g., embodied as transmitter and receiver circuitry in a single communications device), in some implementations comprise separate transmitter and receiver devices, or in other implementations may be embodied in other ways. In one aspect, a transmitter may include or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array that enables each device to perform transmit “beamforming” as described herein. Similarly, a receiver may include or be coupled to multiple antennas (e.g., antennas 316, 326, 356, 366), such as an antenna array that enables each device to perform receive beamforming as described herein. In one aspect, transmitters and receivers may share multiple identical antennas (e.g., antennas 316, 326, 356, 366), such that each device can only receive or transmit at a given time, but not both at the same time. The wireless communication device of the UE 302 and / or base station 304 (e.g., one or both of the transceivers 310 and 320 and / or 350 and 360) may also include a network listen module (NLM) or the like for performing various measurements.

[0054] The UE 302 and base station 304 also, at least in some cases, include satellite positioning system (SPS) receivers 330 and 370. The SPS receivers 330 and 370 may be connected to one or more antennas 336 and 376, respectively, and may provide a means for receiving and / or measuring SPS signals 338 and 378, respectively, such as Global Positioning System (GPS) signals, Global Navigation Satellite System (GLONASS) signals, Galileo signals, Beidou signals, Navigation Satellite System of India (NAVIC), Quasi-Zenith Satellite System (QZSS), etc. The SPS receivers 330 and 370 may comprise any suitable hardware and / or software for receiving and processing the SPS signals 338 and 378, respectively. The SPS receivers 330 and 370 request information and actions from other systems as appropriate and perform the necessary calculations to determine the position of the UE 302 and base station 304 using the obtained measurements, via any suitable SPS algorithms.

[0055] The base station 304 and the network entity 306 each include at least one network interface 380 and 390, respectively, that provide means for communicating (e.g., means for transmitting, means for receiving, etc.) with other network entities. For example, the network interfaces 380 and 390 (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 380 and 390 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.

[0056] The UE 302, base station 304, and network entity 306 also include other components that may be used in conjunction with operations as disclosed herein. The UE 302 includes processor circuitry implementing a processing system 332, e.g., for providing functionality related to wireless positioning and for providing other processing functionality. The base station 304 includes a processing system 384, e.g., for providing functionality related to wireless positioning and for providing other processing functionality. The network entity 306 includes a processing system 394, e.g., for providing functionality related to wireless positioning and for providing other processing functionality. Thus, the processing systems 332, 384, and 394 may provide means for processing, such as means for determining, means for calculating, means for receiving, means for transmitting, means for indicating, etc. In one aspect, the processing systems 332, 384, and 394 may include, for example, one or more general-purpose processors, multi-core processors, ASICs, digital signal processors (DSPs), field programmable gate arrays (FPGAs), or other programmable logic devices or processing circuitry.

[0057] The UE 302, the base station 304, and the network entity 306 include memory circuitry implementing memory components 340, 386, and 396, respectively (e.g., each including a memory device) for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, etc.). Thus, the memory components 340, 386, and 396 may provide a means for storing, a means for retrieving, a means for retaining, etc. In some cases, the UE 302, the base station 304, and the network entity 306 may include positioning components 342, 388, and 398, respectively. The positioning components 342, 388, and 398 may be hardware circuits that are part of or coupled to the processing systems 332, 384, and 394, respectively, that, when executed, cause the UE 302, the base station 304, and the network entity 306 to perform the functionality described herein. In other aspects, positioning components 342, 388, and 398 may be external to processing systems 332, 384, and 394 (e.g., may be part of a modem processing system, may be integrated with another processing system, etc.). Alternatively, positioning components 342, 388, and 398 may be memory modules stored in memory components 340, 386, and 396, respectively, that, when executed by processing systems 332, 384, and 394 (or modem processing system, another processing system, etc.), cause UE 302, base station 304, and network entity 306 to perform the functionality described herein. FIG. 3A shows possible locations for positioning component 342, which may be part of WWAN transceiver 310, memory component 340, processing system 332, or any combination thereof, or may be a stand-alone component. FIG. 3B illustrates possible locations for a positioning component 388, which may be part of the WWAN transceiver 350, memory component 386, processing system 384, or any combination thereof, or may be a stand-alone component.FIG. 3C illustrates possible locations for a positioning component 398, which may be part of the network interface 390, memory component 396, processing system 394, or any combination thereof, or may be a stand-alone component.

[0058] The UE 302 may include one or more sensors 344 coupled to the processing system 332 to provide a means for sensing or detecting motion and / or orientation information that is independent of motion data derived from signals received by the WWAN transceiver 310, the WLAN transceiver 320, and / or the SPS receiver 330. By way of example, the sensors 344 may include an accelerometer (e.g., a microelectromechanical system (MEMS) device), a gyroscope, a geomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometric altimeter), and / or any other type of motion detection sensor. Moreover, the sensors 344 may include multiple different types of devices and combine their outputs to provide motion information. For example, the sensors 344 may use a combination of a multi-axis accelerometer and an orientation sensor to provide the ability to calculate a position in a 2D and / or 3D coordinate system.

[0059] Additionally, the UE 302 includes a user interface 346 that provides a means for providing instructions (e.g., audio and / or visual instructions) to a user and / or receiving user input (e.g., upon user actuation of a sensing device such as a keypad, touch screen, microphone, etc.). Although not shown, the base station 304 and the network entity 306 may also include user interfaces.

[0060] Referring more particularly to the processing system 384, on the downlink, IP packets from the network entity 306 may be provided to the processing system 384. The processing system 384 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 384 may provide RRC layer functionality related to broadcasting of system information (e.g., Master Information Block (MIB), System Information Block (SIB)), 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 related to header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality related to transfer of upper layer PDUs, error correction through automatic repeat request (ARQ), concatenation, segmentation, and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality related to mapping between logical channels and transport channels, scheduling information reporting, error correction, priority handling, and logical channel prioritization.

[0061] The transmitter 354 and receiver 352 may implement Layer 1 (L1) functionality related to various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on transport channels, forward error correction (FEC) coding / decoding of transport channels, interleaving, rate matching, mapping onto physical channels, modulation / demodulation of physical channels, and MIMO antenna processing. The transmitter 354 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-ary quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an orthogonal frequency division multiplexing (OFDM) subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM symbol stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator may be used to determine coding and modulation schemes and for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the UE 302. Each spatial stream may then be provided to one or more different antennas 356. The transmitter 354 may modulate an RF carrier with the respective spatial stream for transmission.

[0062] At the UE 302, the receiver 312 receives signals through its respective antenna 316. The receiver 312 recovers the information modulated onto the RF carriers and provides the information to the processing system 332. The transmitter 314 and receiver 312 perform Layer 1 functionality related to various signal processing functions. The receiver 312 may perform spatial processing on the information to recover any spatial streams destined for the UE 302. If multiple spatial streams are destined for the UE 302, they may be combined into a single OFDM symbol stream by the receiver 312. The receiver 312 then converts the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency-domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the signal constellation point that was most likely transmitted by the base station 304. These soft decisions may be based on channel estimates calculated by a channel estimator. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the base station 304. The data and control signals are then provided to a processing system 332 that performs Layer 3 (L3) and Layer 2 (L2) functionality.

[0063] In the uplink, the processing system 332 performs demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the core network. The processing system 332 is also responsible for error detection.

[0064] Similar to the functionality described with respect to downlink transmissions by the base station 304, the processing system 332 provides RRC layer functionality related to system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality related to header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality related to transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality related to 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 via hybrid automatic repeat request (HARQ), priority handling, and logical channel prioritization.

[0065] Channel estimates derived by the channel estimator from a reference signal or feedback transmitted by the base station 304 may be used by the transmitter 314 to select an appropriate coding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the transmitter 314 may be provided to different antennas 316. The transmitter 314 may modulate an RF carrier with each spatial stream for transmission.

[0066] Uplink transmissions are processed at the base station 304 in a manner similar to that described with respect to the receiver function at the UE 302. The receiver 352 receives the signal through its respective antenna 356. The receiver 352 recovers the information modulated onto the RF carrier and provides the information to the processing system 384.

[0067] In the uplink, the processing system 384 performs demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the UE 302. The IP packets from the processing system 384 may be provided to the core network. The processing system 384 is also responsible for error detection.

[0068] For convenience, the UE 302, the base station 304, and / or the network entity 306 are illustrated in Figures 3A-3C as including various components that may be configured in accordance with various examples described herein. However, it will be appreciated that the illustrated blocks may have different functionality in different designs.

[0069] The various components of the UE 302, the base station 304, and the network entity 306 may communicate with each other via data buses 334, 382, and 392, respectively. The components of FIGS. 3A-3C may be implemented in various ways. In some implementations, the components of FIGS. 3A-3C 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), where each circuit may use and / or incorporate at least one memory component for storing information or executable code used by the circuit to provide its functionality. For example, some or all of the functionality represented by blocks 310-346 may be performed by the processor and memory components of the UE 302 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). Similarly, some or all of the functionality represented by blocks 350-388 may be performed by the processor and memory components of the base station 304 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). Additionally, some or all of the functionality represented by blocks 390-398 may be implemented by the processor and memory components of the network entity 306 (e.g., by execution of appropriate code and / or by appropriate configuration of the processor components). For simplicity, various operations, acts, and / or functions are described herein as being performed "by the UE," "by the base station," "by the network entity," etc. However, it will be appreciated that such operations, acts, and / or functions may actually be performed by particular components or combinations of components of the UE 302, base station 304, network entity 306, etc., such as processing systems 332, 384, 394, transceivers 310, 320, 350, and 360, memory components 340, 386, and 396, positioning components 342, 388, and 398, etc.

[0070] NR supports several cellular network-based positioning techniques, including downlink-based positioning methods, uplink-based positioning methods, 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 (ToA) of reference signals (e.g., PRS, TRS, CSI-RS, SSB, etc.) received from pairs of base stations, called reference signal time difference (RSTD) or time difference of arrival (TDOA) measurements, and reports them to a positioning entity. More specifically, the UE receives identifiers (IDs) of a reference base station (e.g., a serving base station) and multiple non-reference base stations in assistance data. The UE then measures 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 location of the UE. For DL-AoD positioning, the base station measures the angle and other channel characteristics (e.g., signal strength) of the downlink transmit beam used to communicate with the UE to estimate the UE's location.

[0071] 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 an uplink reference signal (e.g., SRS) transmitted by the UE. For UL-AoA positioning, the base station measures the angle and other channel characteristics (e.g., gain level) of the uplink receive beam used to communicate with the UE to estimate the UE's location.

[0072] Downlink and uplink-based positioning methods include extended cell ID (E-CID) positioning and multi-round trip time (RTT) positioning (also called "multi-cell RTT"). In the RTT procedure, an initiator (base station or UE) transmits an RTT measurement signal (e.g., PRS or SRS) to a responder (UE or base station), and the responder transmits an RTT response signal (e.g., 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, called 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, called the "Tx-Rx" measurement. The propagation time (also called "time of flight") between the initiator and the responder can be calculated from the Tx-Rx measurement and the Rx-Tx measurement. Based on the propagation time and the known speed of light, the distance between the initiator and responder can be determined. For multi-RTT positioning, the UE performs RTT procedures with multiple base stations to allow the UE's 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.

[0073] The E-CID positioning method is based on radio resource management (RRM) measurements. In E-CID, the UE reports the serving cell ID, timing advance (TA), and the identities, estimated timing, and signal strength of detected neighboring base stations. The UE's location is then estimated based on this information and the known locations of the base stations.

[0074] To assist in positioning operations, a location server (e.g., location server 230, LMF 270, SLP 272) may provide assistance data to the UE. For example, the assistance data may include identifiers of base stations (or base station cells / TRPs) from which to measure reference signals, reference signal configuration parameters (e.g., number of consecutive positioning subframes, periodicity of the positioning subframes, muting sequence, frequency hopping sequence, reference signal identifier, reference signal bandwidth, etc.), and / or other parameters applicable to a particular positioning method. Alternatively, the assistance data may originate directly from the base stations themselves (e.g., in periodically broadcast overhead messages, etc.), and in some cases, the UE may be able to detect neighboring network nodes itself without using the assistance data.

[0075] In the case of OTDOA or DL-TDOA positioning procedures, the assistance data may further include an expected RSTD value and an associated uncertainty around the expected RSTD, i.e., a search window. In some cases, the value range for the expected RSTD may be + / - 500 microseconds (μs). In some cases, when any of the resources used for positioning measurements are in FR1, the value range for the expected RSTD uncertainty may be + / - 32 μs. In other cases, when all of the resources used for positioning measurements are in FR2, the value range for the expected RSTD uncertainty may be + / - 8 μs.

[0076] A location estimate may be referred to by other names, such as a position estimate, location, position, position fix, fix, etc. A location estimate may be geodetic and comprise coordinates (e.g., latitude, longitude, and possibly altitude), or may be urban and comprise a street address, postal address, or some other linguistic description of the location. A location estimate may also be specified relative to some other known location or may be specified 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 that the location is expected to fall within, with some specified or default level of confidence).

[0077] Various frame structures may be used to support downlink and uplink transmissions between network nodes (e.g., base stations and UEs). Figure 4A is a diagram 400 illustrating an example of a downlink frame structure according to an embodiment of the present disclosure. Figure 4B is a diagram 430 illustrating an example of channels within a downlink frame structure according to an embodiment of the present disclosure. Figure 4C is a diagram 450 illustrating an example of an uplink frame structure according to an embodiment of the present disclosure. Figure 4D is a diagram 470 illustrating an example of channels within an uplink frame structure according to an embodiment of the present disclosure. Other wireless communication technologies may have different frame structures and / or different channels.

[0078] LTE, and possibly NR, utilizes OFDM on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. However, unlike LTE, NR has the option to also use OFDM on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. Generally, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may depend on the system bandwidth. For example, the subcarrier spacing may be 15 kilohertz (kHz), and the minimum resource allocation (resource block) may be 12 subcarriers (i.e., 180 kHz). Thus, the nominal FFT size may be equal to 128, 256, 512, 1024, or 2048 for a system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (i.e., 6 resource blocks), and there may be 1, 2, 4, 8, or 16 subbands for a system bandwidth of 1.25, 2.5, 5, 10, or 20 MHz, respectively.

[0079] LTE supports a single numerology (subcarrier spacing (SCS), symbol length, etc.). In contrast, NR may support multiple numerologies (μ), e.g., subcarrier spacings of 15 kHz (μ=0), 30 kHz (μ=1), 60 kHz (μ=2), 120 kHz (μ=3), and 240 kHz (μ=4) or greater may be available. At each subcarrier spacing, there are 14 symbols per slot. For a 15 kHz SCS (μ=0), there is one slot per subframe, i.e., 10 slots per frame, with a slot duration of 1 millisecond (ms), a symbol duration of 66.7 microseconds (μs), and a maximum nominal system bandwidth (in MHz) of 50 with an FFT size of 4K. For a 30 kHz SCS (μ=1), there are two slots per subframe, i.e., 20 slots per frame, with a slot duration of 0.5 ms, a symbol duration of 33.3 μs, and a maximum nominal system bandwidth (in MHz) of 100 for a 4K FFT size. For a 60 kHz SCS (μ=2), there are four slots per subframe, i.e., 40 slots per frame, with a slot duration of 0.25 ms, a symbol duration of 16.7 μs, and a maximum nominal system bandwidth (in MHz) of 200 for a 4K FFT size. For a 120 kHz SCS (μ=3), there are eight slots per subframe, i.e., 80 slots per frame, with a slot duration of 0.125 ms, a symbol duration of 8.33 μs, and a maximum nominal system bandwidth (in MHz) of 400 for a 4K FFT size. For a 240 kHz SCS (μ=4), there are 16 slots per subframe, i.e., 160 slots per frame, the slot duration is 0.0625 ms, the symbol duration is 4.17 μs, and the maximum nominal system bandwidth (in MHz) with an FFT size of 4K is 800.

[0080] In the example of Figures 4A-4D, a 15 kHz numerology is used. Thus, in the time domain, a 10 ms frame is divided into 10 equal-sized subframes of 1 ms each, with each subframe containing one time slot. In Figures 4A-4D, time is represented horizontally (on the x-axis) with time increasing from left to right, and frequency is represented vertically (on the y-axis) with frequency increasing (or decreasing) from bottom to top.

[0081] A resource grid may be used to represent a time slot, and each time slot includes one or more time-parallel resource blocks (RBs) (also called 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 FIGS. 4A-4D, for a normal cyclic prefix, an RB may include 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols in the time domain to obtain a total of 84 REs. For an extended cyclic prefix, an RB may include 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain to obtain a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme.

[0082] Some of the REs carry downlink reference (pilot) signals (DL-RS), which may include PRS, TRS, PTRS, CRS, CSI-RS, DMRS, PSS, SSS, SSB, etc. Figure 4A shows example locations of REs (labeled "R") carrying PRS.

[0083] PRS is defined for NR positioning to enable the UE to detect and measure more neighbor TRPs. Several configurations are supported to enable various deployments (e.g., indoor, outdoor, sub-6, mmW, etc.). In NR, both UE-assisted and UE-based location calculations are supported. In addition, positioning is supported in RRC CONNECTED, IDLE, and INACTIVE modes. The following table summarizes the types of reference signals that may be used for positioning measurements for various positioning methods.

[0084] [Table 1]

[0085] PRS may be transmitted periodically, aperiodically, or on-demand. On-demand PRS refers to a request by a target device (e.g., a UE or another entity) for appropriate PRS resources (e.g., a subset of TRPs, a specific direction / beam, periodicity, PRS configuration, etc.) based on needs / demand determined by the target device. NR DL-PRS designs for FR1 and FR2 are expected to support localized (in time) NR DL-PRS transmissions with periodic and / or on-demand resource allocation. However, signaling details for periodic and on-demand resource allocations are not fully specified. For example, signaling may allow for an increase in resources allocated for DL-PRS transmissions (e.g., increased bandwidth, a specific TRP, or beam direction) and may indicate when DL-PRS transmissions are no longer needed. Increased DL-PRS transmissions may be simplified by being constrained to only a few PRS configurations that may be configured in the gNB and / or LMF. For example, if there is no request for increased PRS transmission, there may be one set of PRS configuration parameters that corresponds to "normal" PRS transmission. In some networks, "normal" PRS transmission may be equivalent to no PRS transmission at all (to minimize resource usage). There may then be one or more levels of increased PRS transmission, each associated with a different set of PRS configuration parameters. In the simplest case, PRS transmission may be turned on only when needed and turned off when not needed according to a default set of PRS configuration parameters.

[0086] A set of resource elements (REs) used for transmitting a PRS is called a "PRS resource." A set of resource elements can span multiple PRBs in the frequency domain and "N" (e.g., one or more) consecutive symbols within a slot in the time domain. Within a given OFDM symbol in the time domain, PRS resources occupy consecutive PRBs in the frequency domain.

[0087] The transmission of PRS resources within a given PRB has a particular comb size (also called "comb density"). The comb size "N" represents the subcarrier spacing (or frequency / tone spacing) within each symbol of the PRS resource configuration. Specifically, for comb size "N," a PRS is transmitted in every Nth subcarrier of a symbol of the PRB. For example, for comb 4, for each symbol of the PRS resource configuration, REs corresponding to every fourth subcarrier (subcarriers 0, 4, 8, etc.) are used to transmit the PRS of the PRS resource. Currently, the following comb sizes are supported for DL-PRS: comb 2, comb 4, comb 6, and comb 12. Figure 4A shows an example PRS resource configuration for comb 6 (spanning six symbols). That is, the location of the shaded REs (labeled "R") indicates the comb 6 PRS resource configuration.

[0088] Currently, DL-PRS resources can span 2, 4, 6, or 12 consecutive symbols within a slot with a staggered pattern across the frequency domain. DL-PRS resources can be configured within any higher layer configured downlink or flexible (FL) symbols of a slot. There can be a constant energy per resource element (EPRE) for all REs of a given DL-PRS resource. Below are the symbol-to-symbol frequency offsets for comb sizes 2, 4, 6, and 12 across 2, 4, 6, and 12 symbols: 2-symbol-comb2: {0, 1}, 4-symbol-comb2: {0, 1, 0, 1}, 6-symbol-comb2: {0, 1, 0, 1, 0, 1}, 12-symbol-comb2: {0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}, 4-symbol-comb4: {0, 2, 1, 3}, 12-symbol-comb4: {0, 2, 1, 3, 0, 2, 1, 3, 0, 2, 1, 3}, 6-symbol-comb6: {0, 3, 1, 4, 2, 5}, 12-symbol-comb6: {0, 3, 1, 4, 2, 5, 0, 3, 1, 4, 2, 5}, and 12-symbol-comb12: {0, 6, 3, 9, 1, 7, 4,10, 2, 8, 5,11}.

[0089] A "PRS resource set" is a set of PRS resources used for transmitting PRS signals, where each PRS resource has a PRS resource ID. In addition, PRS resources within a PRS resource set are associated with the same TRP. A PRS resource set is identified by a PRS resource set ID and associated with a specific TRP (identified by a TRP ID). In addition, PRS resources within a PRS resource set have the same periodicity across slots, a common muting pattern configuration, and the same repetition factor (e.g., "PRS-ResourceRepetitionFactor"). Periodicity is the time from the first repetition of the first PRS resource of the first PRS instance to the same first repetition of the same first PRS resource of the next PRS instance. The periodicity may have a length selected from 2^μ*{4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, 320, 640, 1280, 2560, 5120, 10240} slots with μ=0, 1, 2, 3. The repetition factor may have a length selected from {1, 2, 4, 6, 8, 16, 32} slots.

[0090] A PRS resource ID in a PRS resource set is associated with a single beam (or beam ID) transmitted from a single TRP (where a TRP may transmit one or more beams). That is, each PRS resource in a PRS resource set may be transmitted on a different beam, and thus a "PRS resource" or simply a "resource" may also be referred to as a "beam." Note that this does not have any implications as to whether the TRP and the beam on which the PRS is transmitted are known to the UE.

[0091] A "PRS instance" or "PRS occasion" is one instance of a periodically repeating time window (e.g., a group of one or more contiguous slots) during which a PRS is expected to be transmitted. A PRS occasion may also be referred to as a "PRS positioning occasion," "PRS positioning instance," "positioning occasion," "positioning instance," "positioning repetition," or simply an "occasion," "instance," or "repetition."

[0092] A "positioning frequency layer" (also simply referred to as a "frequency layer") is a collection of one or more PRS resource sets across one or more TRPs with the same values for several parameters. In particular, the collection of PRS resource sets has the same subcarrier spacing and cyclic prefix (CP) type (meaning that all numerologies supported for PDSCH are also supported for PRS), the same Point A, the same value of downlink PRS bandwidth, the same starting PRB (and center frequency), and the same comb size. The Point A parameter takes the value of the parameter "ARFCN-ValueNR" (where "ARFCN" stands for "absolute radio frequency channel number"), which is an identifier / code that specifies a pair of physical radio channels used for transmission and reception. The downlink PRS bandwidth may have a granularity of four PRBs, with a minimum of 24 PRBs and a maximum of 272 PRBs. Currently, up to four frequency layers are defined, and up to two PRS resource sets per TRP per frequency layer can be configured.

[0093] The concept of a frequency layer is somewhat similar to that of a component carrier and bandwidth portion (BWP), but differs in that a component carrier and BWP are used by one base station (or a macrocell base station and a small cell base station) to transmit a data channel, while a frequency layer is used by several (usually three or more) base stations to transmit a PRS. A UE may indicate the number of frequency layers it can support when it sends its positioning capabilities to the network, such as during an LTE Positioning Protocol (LPP) session. For example, the UE may indicate whether it can support one positioning frequency layer or four positioning frequency layers.

[0094] Figure 4B shows an example of various channels within a downlink slot of a radio frame. In NR, the channel bandwidth or system bandwidth is divided into multiple BWPs. A BWP is a contiguous set of PRBs selected from a contiguous subset of common RBs for a given numerology on a given carrier. Generally, up to 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 that a UE can only receive or transmit via one BWP at a time. On the downlink, the bandwidth of each BWP should be equal to or greater than the bandwidth of an SSB, but each BWP may or may not include an SSB.

[0095] Referring to FIG. 4B, a primary synchronization signal (PSS) is used by a UE to determine subframe / symbol timing and physical layer identity. A secondary synchronization signal (SSS) is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the PCI. Based on the PCI, the UE can determine the location of the DL-RS mentioned above. A physical broadcast channel (PBCH) carrying an MIB may be logically grouped with the PSS and SSS to form an SSB (also referred to as SS / PBCH). The MIB provides the number of RBs in the downlink system bandwidth and the system frame number (SFN). A physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted over the PBCH, such as system information blocks (SIBs), and paging messages.

[0096] The physical downlink control channel (PDCCH) carries downlink control information (DCI) in one or more control channel elements (CCEs), each of which contains one or more RE group (REG) bundles (which may span multiple symbols in the time domain). Each REG bundle contains one or more REGs, and each REG corresponds to 12 resource elements (one resource block) in the frequency domain and one OFDM symbol in the time domain. The set of physical resources used to carry the PDCCH / DCI is called a control resource set (core set (CORESET)) in NR. In NR, the PDCCH is confined to a single core set and transmitted with its own DMRS. This enables UE-specific beamforming for the PDCCH.

[0097] In the example of Figure 4B, there is one core set per BWP, and the core set spans three symbols in the time domain (although it could be only one or two symbols). Unlike LTE control channels, which occupy the entire system bandwidth, in NR, the PDCCH channel is localized to a specific region (i.e., a core set) in the frequency domain. Therefore, the frequency components of the PDCCH shown in Figure 4B are illustrated as being smaller than a single BWP in the frequency domain. Note that while the illustrated core sets are contiguous in the frequency domain, this is not required. Additionally, the core sets may span less than three symbols in the time domain.

[0098] The DCI in the PDCCH carries information about uplink resource allocations (persistent and non-persistent), called uplink grants and downlink grants, respectively, and a description of the downlink data to be transmitted to the UE. More specifically, the DCI indicates the resources scheduled for the downlink data channel (e.g., PDSCH) and the uplink data channel (e.g., PUSCH). Multiple (e.g., up to eight) DCIs may be configured in the PDCCH, and these DCIs may have one of multiple formats. For example, there are various DCI formats for uplink scheduling, for downlink scheduling, for uplink transmit power control (TPC), etc. The PDCCH may be transported by 1, 2, 4, 8, or 16 CCEs to accommodate different DCI payload sizes or coding rates.

[0099] As shown in FIG. 4C , some of the REs (labeled “R”) carry DMRS for channel estimation at a receiver (e.g., a base station, another UE, etc.). The UE may additionally transmit an SRS, for example, in the last symbol of a slot. The SRS may have a comb structure, and the UE may transmit the SRS in one of the combs. In the example of FIG. 4C , the illustrated SRS is comb 2 spanning one symbol. The SRS may be used by the base station to obtain channel state information (CSI) for each UE. The CSI describes how an RF signal propagates from the UE to the base station and represents the combined effects of scattering, fading, and power attenuation with distance. The system uses the SRS for resource scheduling, link adaptation, massive MIMO, beam management, etc.

[0100] Currently, an SRS resource can span 1, 2, 4, 8, or 12 consecutive symbols within a slot with comb sizes Comb 2, Comb 4, or Comb 8. Below are the symbol-to-symbol frequency offsets for the currently supported SRS comb patterns: 1 Symbol Com2: {0}, 2 Symbol Com2: {0, 1}, 4 Symbol Com2: {0, 1, 0, 1}, 4 Symbol Com4: {0, 2, 1, 3}, 8 Symbol Com4: {0, 2, 1, 3, 0, 2, 1, 3}, 12 Symbol Com4: {0, 2, 1, 3, 0, 2, 1, 3, 0, 2, 1, 3}, 4 Symbol Com8: {0, 4, 2, 6}, 8 Symbol Com8: {0, 4, 2, 6, 1, 5, 3, 7}, and 12 Symbol Com8: {0, 4, 2, 6, 1, 5, 3, 7, 0, 4, 2, 6}.

[0101] A set of resource elements used for transmitting an SRS is called an "SRS resource" and may be identified by a parameter "SRS-ResourceId." The set of resource elements may span multiple PRBs in the frequency domain and N (e.g., one or more) consecutive symbols within a slot in the time domain. Within a given OFDM symbol, SRS resources occupy consecutive PRBs. An "SRS resource set" is a set of SRS resources used for transmitting an SRS signal and is identified by an SRS resource set ID ("SRS-ResourceSetId").

[0102] Generally, a UE transmits an SRS to enable a receiving base station (either a serving base station or a neighboring base station) to measure the channel quality between the UE and the base station. However, the SRS can also be used as an uplink positioning reference signal for uplink positioning procedures such as UL-TDOA, multi-RTT, DL-AoA, etc.

[0103] Several extensions beyond the previous definition of SRS have been proposed for positioning SRS (also called "UL-PRS"), such as a new staggered pattern in SRS resources (except for single symbol / comb2), a new comb type for SRS, a new sequence for SRS, more SRS resource sets per component carrier, and more SRS resources per component carrier. In addition, the parameters "SpatialRelationInfo" and "PathLossReference" will be configured based on downlink reference signals or SSBs from neighboring TRPs. Still further, one SRS resource may be transmitted outside the active BWP, and one SRS resource may span multiple component carriers. Also, the SRS may be configured in the RRC connected state and may only be transmitted within the active BWP. Furthermore, there may be no frequency hopping, no repetition factor, a single antenna port, and new lengths for the SRS (e.g., 8 and 12 symbols). Also, there may be open-loop power control rather than closed-loop power control, and Com8 (i.e., SRS transmitted on every 8th subcarrier in the same symbol) may be used. Finally, the UE may transmit from multiple SRS resources over the same transmit beam for UL-AoA. All of these are additional features to the current SRS framework, configured through RRC higher layer signaling (and potentially triggered or activated through the MAC Control Element (CE) or DCI).

[0104] FIG. 4D illustrates an example of various channels within an uplink slot of a frame according to an aspect of the present disclosure. A random access channel (RACH), also referred to as a physical random access channel (PRACH), may be present within one or more slots within a frame based on a PRACH configuration. The PRACH may include six consecutive RB pairs within a slot. The PRACH enables a UE to perform initial system access and achieve uplink synchronization. A physical uplink control channel (PUCCH) may be located on the edge of the uplink system bandwidth. The PUCCH carries uplink control information (UCI), such as scheduling requests, CSI reports, channel quality indicators (CQIs), precoding matrix indicators (PMIs), rank indicators (RIs), and HARQ ACK / NACK feedback. The physical uplink shared channel (PUSCH) carries data and may additionally be used to carry buffer status reports (BSRs), power headroom reports (PHRs), and / or UCI.

[0105] It should be noted that the terms “positioning reference signal” and “PRS” generally refer to specific reference signals used for positioning in NR and LTE systems. However, as used herein, the terms “positioning reference signal” and “PRS” may also refer to any type of reference signal that may be used for positioning, such as, but not limited to, PRS, TRS, PTRS, CRS, CSI-RS, DMRS, PSS, SSS, SSB, SRS, UL-PRS, as defined in LTE and NR. In addition, the terms “positioning reference signal” and “PRS” may refer to downlink or uplink positioning reference signals, unless otherwise specified by the context. If necessary to further distinguish between types of PRS, downlink positioning reference signals may be referred to as “DL-PRS,” and uplink positioning reference signals (e.g., SRS, PTRS for positioning) may be referred to as “UL-PRS.” Additionally, for signals that can be transmitted in both the uplink and downlink (e.g., DMRS, PTRS), "UL" or "DL" may be prepended to the signal to distinguish the direction. For example, "UL-DMRS" may be distinguished from "DL-DMRS."

[0106] To establish uplink synchronization and a radio resource control (RRC) connection with a base station (or, more specifically, a serving cell / TRP), a UE needs to perform a random access procedure (also called a random access channel (RACH) procedure or a physical random access channel (PRACH) procedure). There are two types of random access available in NR: contention-based random access (CBRA), also called "four-step" random access, and contention-free random access (CFRA), also called "three-step" random access. In some cases, there is also a "two-step" random access procedure that may be performed instead of the four-step random access procedure.

[0107] 5 illustrates an example four-step random access procedure 500 according to an aspect of the present disclosure. The four-step random access procedure 500 is performed between a UE 504 and a base station 502 (illustrated as a gNB), which may correspond to any of the UEs and base stations, respectively, described herein.

[0108] There are various situations in which the UE 504 may perform the four-step random access procedure 500. For example, the UE 504 may perform the four-step random access procedure 500 when performing an initial RRC connection setup (i.e., gaining initial network access after exiting an RRC IDLE state), when performing an RRC connection re-establishment procedure, when the UE 504 has uplink data to transmit, when the UE 504 has uplink data to transmit and the UE 504 is in an RRC CONNECTED state but has no PUCCH resources available for a scheduling request (SR), or when there is a scheduling request failure.

[0109] Before performing the four-step random access procedure 500, the UE 504 reads one or more synchronization signal blocks (SSBs) broadcast by the base station 502 with which the UE 504 is performing the four-step random access procedure 500. In NR, each beam transmitted by a base station (e.g., base station 502) is associated with a different SSB, and the UE (e.g., UE 504) selects several beams to use to communicate with the base station 502. Based on the SSB of the selected beam, the UE 504 can then read a system information block (SIB) type 1 (SIB1), which carries cell access-related information and provides the UE 504 with scheduling of other system information blocks to be transmitted on the selected beam.

[0110] When a UE 504 sends the very first message of the four-step random access procedure 500 to a base station 502, it sends a specific pattern called a "preamble" (also called a "RACH preamble," "PRACH preamble," or "sequence"). The preamble distinguishes requests from different UEs 504. In CBRA, a UE 504 randomly selects a preamble from a pool of preambles (64 in NR) that are shared with other UEs 504. However, if two UEs 504 use the same preamble simultaneously, there may be a collision or contention.

[0111] Thus, at 510, the UE 504 selects one of 64 preambles to send to the base station 502 in a random access request (also referred to as a “RACH request”). This message is called “Message 1” or “Msg1” in the four-step random access procedure 500. Based on synchronization information (e.g., SIB1) from the base station 502, the UE 504 sends the preamble in the RACH occasion (RO) corresponding to the selected SSB / beam. More specifically, a specific mapping is defined between the SSBs and the ROs (occurring every 10, 20, 40, 80, or 160 ms) for the base station 502 to determine which beam the UE 504 has selected. By detecting in which RO the UE 504 sent the preamble, the base station 502 can determine which SSB / beam the UE 504 has selected.

[0112] Note that an RO is a time-frequency transmission opportunity for transmitting a preamble, and the preamble index (i.e., a value from 0 to 63 for 64 possible preambles) enables the UE 504 to generate a preamble of the type expected at the base station 502. The RO and preamble index may be configured for the UE 504 by the base station 502 in a SIB. A RACH resource is an RO in which one preamble index is transmitted. Thus, the terms "RO" (or "RACH occasion") and "RACH resource" may be used interchangeably depending on the context.

[0113] Due to reciprocity, the UE 504 may use the uplink transmit beam corresponding to the best downlink receive beam determined during synchronization (i.e., the best receive beam for receiving the selected downlink beam from the base station 502). That is, the UE 504 determines the parameters of the uplink transmit beam using the parameters of the downlink receive beam used to receive the SSB beam from the base station 502. If reciprocity is available at the base station 502, the UE 504 may transmit a preamble via one beam. Otherwise, the UE 504 repeats transmitting the same preamble in all of its uplink transmit beams.

[0114] The UE 504 also needs to provide its identity to the network (via the base station 502) so that the network can address the UE 504 in the next steps. This identity is called the random access radio network temporary identity (RA-RNTI) and is determined from the time slot in which the preamble is sent.

[0115] If the UE 504 does not receive a response from the base station 502 within some period of time, it increases its transmit power by a fixed step and sends the preamble / Msg1 again. More specifically, the UE 504 transmits a first set of repetitions of the preamble, and then, if it does not receive a response, it increases its transmit power and transmits a second set of repetitions of the preamble. The UE 504 continues to increase its transmit power in incremental steps until it receives a response from the base station 502.

[0116] At 520, the base station 502 sends a random access response (RAR), referred to as “message 2” or “Msg2” in the four-step random access procedure 500, to the UE 504 on the selected beam. The RAR is sent on the physical downlink shared channel (PDSCH) and addressed to the RA-RNTI calculated from the time slot (i.e., RO) in which the preamble was sent. The RAR carries the following information: a cell-radio network temporary identifier (C-RNTI), a timing advance (TA) value, and uplink grant resources. The base station 502 assigns the C-RNTI to the UE 504 to enable further communication with the UE 504. The TA value specifies how much the UE 504 should change its timing to compensate for the propagation delay between the UE 504 and the base station 502. The uplink grant resources indicate the initial resources the UE 504 can use on the physical uplink shared channel (PUSCH). After this step, the UE 504 and base station 502 establish a coarse beam alignment that can be utilized in subsequent steps.

[0117] At 530, using the allocated PUSCH, the UE 504 sends an RRC connection request message, referred to as "Message 3" or "Msg3," to the base station 502. Because the UE 504 sends Msg3 over resources scheduled by the base station 502, the base station 502 knows where (spatially) to detect Msg3 and therefore which uplink receive beam to use. Note that the Msg3 PUSCH can be sent on the same or a different uplink transmit beam as Msg1.

[0118] The UE 504 identifies itself in Msg3 by the C-RNTI assigned in the previous step. The message includes the identity of the UE 504 and a connection establishment cause. The identity of the UE 504 is either a temporary mobile subscriber identity (TMSI) or a random value. If the UE 504 has previously connected to the same network, the TMSI is used. The UE 504 is identified in the core network by the TMSI. If the UE 504 is connecting to the network for the very first time, a random value is used. The reason for the random value or TMSI is that the C-RNTI may have been assigned to more than one UE 504 in the previous step due to multiple requests arriving simultaneously. The connection establishment cause indicates why the UE 504 needs to connect to the network (e.g., for a positioning session, because the UE 504 has uplink data to send, because the UE 504 has received a page from the network, etc.).

[0119] As mentioned above, the four-step random access procedure 500 is a CBRA procedure. Therefore, as explained above, any UE 504 connected to the same base station 502 can send the same preamble at 510, which may result in collisions or contention between requests from various UEs 504. Therefore, the base station 502 uses a contention resolution mechanism to handle this type of access request. However, with this procedure, the results are random, and not all random access attempts are successful.

[0120] Thus, at 540, if Msg3 is successfully received, base station 502 responds with a contention resolution message referred to as "Message 4" or "Msg4." This message is addressed to the TMSI (from Msg3) or a random value, but includes a new C-RNTI to be used for further communications. In particular, base station 502 sends Msg4 in the PDSCH using the downlink transmit beam determined in the previous step.

[0121] As shown in FIG. 5, the four-step random access procedure 500 requires two round-trip cycles between the UE 504 and the base station 502, which not only increases latency but also incurs additional control signaling overhead. To address these issues, two-step random access is introduced in NR for CBRA. The motivation behind two-step random access is to reduce latency and control signaling overhead by having a single round-trip cycle between the UE and the base station. This is achieved by combining the preamble (Msg1) and the scheduled PUSCH transmission (Msg3) into a single message from the UE to the base station known as RACH message A (“MsgA”). Similarly, the random access response (Msg2) and the contention resolution message (Msg4) are combined into a single message from the base station to the UE known as RACH message B (“MsgB”). This reduces latency and control signaling overhead.

[0122] 6 illustrates an example two-step random access procedure 600 according to an aspect of the present disclosure. The two-step random access procedure 600 may be performed between a UE 604 and a base station 602 (illustrated as a gNB), which may correspond to any of the UEs and base stations, respectively, described herein.

[0123] At 610, the UE 604 transmits MsgA to the base station 602. In the two-step random access procedure 600, Msg1 and Msg3, described above with reference to FIG. 5, are folded (i.e., combined) into MsgA and sent to the base station 602. MsgA therefore includes a preamble and a PUSCH similar to the Msg3 PUSCH of the four-step random access procedure 500. The preamble may have been selected from 64 possible preambles, as described above with reference to FIG. 5, and may be used as a reference signal for demodulating the data transmitted in MsgA. At 620, the UE 604 receives MsgB from the base station 602. MsgB may be a combination of Msg2 and Msg4, described above with reference to FIG. 5.

[0124] The combination of Msg1 and Msg3 into one MsgA and Msg2 and Msg4 into one MsgB allows the UE 604 to reduce random access setup time and support the low latency requirements of NR. The UE 604 may be configured to support the two-step random access procedure 600, but as a fallback in case the UE 604 cannot use the two-step random access procedure 600 due to some constraints (e.g., large transmit power requirements), the UE 604 may still support the four-step random access procedure 500. Thus, the UE 604 in NR may be configured to support both the four-step random access procedure and the two-step random access procedures 5 and 6 and may determine which random access procedure to use based on RACH configuration information received from the base station 602.

[0125] In CFRA (also known as "three-step random access"), the base station assigns a preamble, which is therefore called a "dedicated random access preamble" or simply a "dedicated preamble." A CFRA procedure may be performed when the UE is in the RRC CONNECTED state before a random access procedure, such as in the case of a handover. A CFRA procedure may also be performed for downlink data arrivals when transitioning from the RRC INACTIVE state to the RRC CONNECTED state, when requesting specific system information (called "on-demand SI"), when adding a cell for NR non-standalone (NSA) networking, or when performing beam failure recovery.

[0126] 7 illustrates an example three-step random access procedure 700 according to an aspect of the present disclosure. The three-step random access procedure 700 may be performed between a UE 704 and a base station 702 (illustrated as a gNB), which may correspond to any of the UEs and base stations, respectively, described herein.

[0127] At 710, the base station 702 assigns a dedicated preamble to the UE 704. If the UE 704 is in an RRC IDLE state, the base station 702 provides the dedicated preamble to the UE 704 via RRC signaling (i.e., in an RRC message). Alternatively, if the UE 704 is in an RRC INACTIVE state, the base station 702 provides the dedicated preamble to the UE 704 via physical layer signaling (e.g., DCI on a PDCCH). Because the preamble is specifically assigned to the UE 704, there is no preamble contention with other UEs 704. However, when there are insufficient dedicated preamble resources for the number of UEs 704 requesting random access, the base station 702 instructs the additional UEs 704 to initiate CBRA.

[0128] As described above, the three-step random access procedure 700 may be used in the cases of handover, downlink data arrival, and NSA networking. In the case of handover, the "MobilityControlInfo" information element sent by the source base station 702 carries the allocated preamble. In the case of downlink data arrival (e.g., a physical downlink control channel (PDCCH) command), when the downlink data arrives at the base station 702, the base station 702 instructs the UE 704 to initiate the three-step random access procedure 700 through a DCI command in the PDCCH that carries or identifies the allocated preamble. In the case of NSA networking, when an NR cell is added in the NSA, the base station 702 instructs the UE 704 to initiate the three-step random access procedure 700 through a PDCCH that carries or identifies the allocated preamble.

[0129] At 720, the UE 704 transmits a random access request ("Msg1") to the base station 702, as in 510 of FIG. 5, but using an assigned preamble rather than a randomly selected preamble. At 730, the UE 704 receives a random access response ("Msg2") from the base station 702, as in 520 of FIG. 5. In the case of handover, the random access response at 730 includes timing alignment information and an initial uplink grant for the target base station. In the case of downlink data arrival, when downlink data arrives at the base station 702, the random access response at 730 includes timing alignment information and a random access preamble identifier (RAPID). In the case of NSA networking, when an NR cell is added in the NSA, the random access response at 730 includes timing alignment information and a RAPID.

[0130] As can be seen from the above, the four-step random access procedure 500 typically takes longer to establish an uplink connection compared to the faster and more efficient three-step random access procedure 700. However, as also explained above, a UE may not always be able to perform the three-step random access procedure 700.

[0131] After the random access procedure, the UE is in the RRC CONNECTED state. The RRC protocol is used on the air interface between the UE and the base station. The main functions of the RRC protocol include connection establishment and release functions, system information broadcast, radio bearer establishment, reconfiguration, and release, RRC connection mobility procedures, paging notification and release, and outer loop power control. In LTE, a UE may be in one of two RRC states (CONNECTED or IDLE), while in NR, a UE may be in one of three RRC states (CONNECTED, IDLE, or INACTIVE). Different RRC states have different associated radio resources that the UE can use when the UE is in a given state. Note that while the various RRC states are often written in uppercase as above, this is not required and these states may also be written in lowercase.

[0132] 8 is a diagram 800 of various RRC states (also referred to as RRC modes) available in NR according to an aspect of the present disclosure. When a UE powers up, it is initially in an RRC DISCONNECTED / IDLE state 810. After a random access procedure, the UE moves to an RRC CONNECTED state 820. If there is no activity at the UE for a short period of time, the UE can suspend its session by moving to an RRC INACTIVE state 830. The UE can resume its session by performing a random access procedure and transitioning back to the RRC CONNECTED state 820. Therefore, the UE needs to perform a random access procedure to transition to the RRC CONNECTED state 820, regardless of whether the UE is in the RRC IDLE state 810 or the RRC INACTIVE state 830.

[0133] Operations performed in the RRC IDLE state 810 include Public Land Mobile Network (PLMN) selection, system information broadcast, cell reselection mobility, paging for mobile terminated data (initiated and managed by the 5GC), discontinuous reception (DRX) for core network paging (configured by the Non-Access Stratum (NAS)). Operations performed in the RRC CONNECTED state 820 include 5GC (e.g., 5GC 260) and New RAN (e.g., New RAN 220) connection establishment (both control and user plane), UE context storage in the New RAN and UE, New RAN knowledge of the cell to which the UE belongs, transfer of unicast data to and from the UE, and network-controlled mobility. Operations performed in the RRC INACTIVE state 830 include broadcasting of system information, cell reselection for mobility, paging (initiated by the New RAN), RAN-based Notification Area (RNA) management (by the New RAN), DRX for RAN paging (configured by the New RAN), 5GC and New RAN connection establishment for the UE (both control plane and user plane), storing UE context in the New RAN and UE, and New RAN knowledge of the RNA to which the UE belongs.

[0134] As mentioned above, there are 64 preambles defined in NR, specifically, 64 preambles per time-frequency RACH occasion (RO). Figure 9 is a diagram of an example RACH preamble 900 according to an aspect of the present disclosure. As shown in Figure 9, the RACH preamble 900 consists of two parts: a cyclic prefix (CP) 910 and a set of repetitions of a preamble sequence 920. A guard period (GP) 930 follows.

[0135] The number and length of preamble repetitions are specified in table 950 and vary depending on the format ('0', '1', '2', or '3') of the RACH preamble 900. Table 950 also shows the length (L RA), frequency (Δf RA ), sequence length (N u ), and CP length

[0136]

number

[0137] The preamble format is described below with reference to Figure 9. Note that kappa (k) is defined as 64.

[0138] In NR, there are 13 types of supported preamble formats: Format 0, Format 1, Format 2, Format 3, Format A1, Format A2, Format A3, Format B1, Format B2, Format B3, Format B4, Format C0, and Format C1. These 13 types of preamble formats can be grouped into two categories: long preambles and short preambles. Long preambles are 839 in length, and short preambles are 139 in length. Long preambles use four of the 13 preamble formats, and short preambles use nine of the 13 preamble formats.

[0139] FIG. 10 is a graph 1000 illustrating various preamble lengths and formats in NR. The four formats of long preambles are numbered "Format #0" through "Format #3," and the nine formats of short preambles are numbered "A1" through "A3," "B1" through "B4," and "C0" and "C2." Each row of graph 1000 is an RO. Each RO begins with a cyclic prefix (represented as "C") of some length, has one or more repetitions of a preamble sequence (represented as "S"), and ends with a guard period (represented as "G") of some length. For reference, the last row of graph 1000 shows a PUSCH subframe for a 15 kHz subcarrier spacing. Thus, a subframe comprises one slot, which is 1 ms long and divided into 14 symbols.

[0140] Four formats for long preambles are designed for large-scale (i.e., macro) cell deployments in FR1 and are typically used in frequency bands below 6 GHz. The preamble format (i.e., "0" through "3") is part of the cell's random access configuration (broadcast in the SIB), and each cell is generally limited to a single preamble format. In NR, the numerology used for long preambles differs from other NR transmissions because the origin of long preambles is partially from the preambles used for LTE. For example, preamble formats "0" and "1" in NR are the same as preamble formats "0" and "2" in LTE. Preambles can use subcarrier spacing of 1.25 kHz or 5 kHz. A long preamble with 1.25 kHz subcarrier spacing occupies six resource blocks in the frequency domain, while a preamble with 5 kHz subcarrier spacing occupies 24 resource blocks.

[0141] Short preambles are generally shorter than long preambles and often span only a few OFDM symbols (as shown in Figure 10). Nine formats of short preambles are designed for small cell deployments, including indoor coverage. These preamble formats can be used for both FR1 and FR2 ranges. The subcarrier spacing for short preambles is aligned with the normal NR subcarrier spacing (e.g., 15 kHz, 30 kHz, 60 kHz, and 120 kHz). In FR1, short preambles use 15 or 30 kHz subcarrier spacing, while in FR2, short preambles use 60 or 120 kHz subcarrier spacing. Short preambles occupy 12 resource blocks in the frequency domain regardless of the preamble numerology.

[0142] The short preamble format is designed so that the last part of each OFDM symbol serves as a cyclic prefix for the next OFDM symbol, and the length of the preamble OFDM symbol is equal to the length of the data OFDM symbol. Therefore, in most cases, multiple preamble transmissions can be time-multiplexed within a single RACH slot (when there is a configured number of RACH slots per data slot, see Figure 10 below). In other words, for short preambles, there can be multiple ROs in the frequency domain as well as in the time domain within a single RACH slot (also called a "PRACH slot"). However, it should be noted that a RACH slot is not necessarily equivalent to a data slot, as will be shown below with reference to Figure 10.

[0143] NR supports mixing "A" and "B" preamble formats to allow for additional formats such as "A1 / B1," "A2 / B2," and "A3 / B3." Short preamble formats "A" and "B" are identical except for a somewhat shorter cyclic prefix for the "B" format. Preamble formats "B2" and "B3" are used in combination with the corresponding "A" formats (i.e., "A2" and "A3").

[0144] Short preambles allow the base station receiver to use the same FFT for data and random access preamble detection. These preambles are compositions of multiple shorter OFDM symbols per PRACH preamble, making them more robust to time-varying channel and frequency errors. Short preambles also support analog beam sweeping during PRACH reception, so that the same preamble can be received using different beams at the base station.

[0145] As mentioned above, there are a maximum of 64 preambles possible in NR. This disclosure proposes reserving a subset of these preambles for positioning. As a first option, the set of 64 preambles may be divided into two sets: one set consisting of "N" preambles reserved for communication and one set consisting of "M" preambles reserved (dedicated) for positioning. As a second option, the set of 64 preambles may be divided into three sets: one set consisting of "N" preambles reserved for communication, one set consisting of "N1" preambles reserved for critical communication, and one set consisting of "M" preambles reserved for positioning.

[0146] A base station can broadcast a set of preambles reserved for positioning in what is referred to herein as a “positioning SIB.” Currently, as described above, a base station broadcasts available preambles (or identifiers of available preambles, or parameters needed to calculate available preambles) for random access in various SIBs. Thus, instead of broadcasting only one set of 64 possible preambles, a base station may broadcast two or three sets of available preambles. Preambles reserved for communications may be broadcast as normal (the normal SIB would simply contain / identify fewer preambles), and preambles reserved for positioning may be broadcast in the disclosed positioning SIB. If a base station reserves a set of preambles for critical communications (e.g., low latency, high QoS, etc.), the base station may broadcast such preambles in another SIB that carries only those types of preambles.

[0147] The UE can use a dedicated positioning preamble for a UE-initiated or UE-initiated on-demand positioning request. More specifically, the UE can select the positioning preamble when performing a random access procedure for a positioning session. In this way, the base station knows that the UE is involved in a positioning session, which ensures that the UE receives uplink resources on time and meets the latency requirements of the positioning session. In one aspect, network operators may charge a premium for this feature, and only paid applications will be allowed to use this feature.

[0148] Note that using a dedicated positioning preamble may still result in contention between UEs (if two or more UEs select the same positioning preamble at approximately the same time), but this is expected to be minimal since only the UEs involved in the positioning session are competing for the positioning preamble.

[0149] 11 illustrates an example four-step random access procedure 1100 according to an aspect of the present disclosure. The four-step random access procedure 1100 is performed between a UE 1104 and a base station 1102 (illustrated as a gNB), which may correspond to any of the UEs and base stations, respectively, described herein.

[0150] At 1110, the UE 1104 is in an RRC IDLE or INACTIVE state when a positioning event is detected at the UE 1104. The positioning event may be, for example, a request for the UE 1104 to transmit an uplink positioning reference signal (e.g., a positioning SRS). The request may be received from a location server (e.g., location server 230, LMF 270, SLP 272), a third-party application, an external client, etc.

[0151] At 1120, the UE 1104 selects a positioning preamble (including a RACH positioning sequence) from positioning preambles broadcast by the base station 1102 in one or more positioning SIBs. At 1130, the UE 1104 sends a random access request (Msg1) to the base station 1102, as at 510 in FIG. 5. The random access request includes the selected positioning preamble, thereby indicating to the base station 1102 that the UE 1104 will be involved in a positioning session. At 1140, the base station 1102 responds to the UE 1104 with a random access response (Msg2), as at 520 in FIG. 5.

[0152] At 1150, the UE 1104 sends a connection establishment request (Msg3) to the base station 1102, as at 530 in FIG. 5. The connection establishment request may include a connection establishment cause of "positioning." At 1160, the base station 1102 is aware that the UE 1104 will be involved in a positioning session based on the positioning preamble reception at 1130. Thus, the base station 1102 determines an uplink positioning configuration that the UE 1104 should use to transmit an uplink positioning reference signal (UL-PRS) for the positioning session.

[0153] At 1170, the base station 1102 sends a contention resolution message (Msg4) to the UE 1104, as in 540 of FIG. 5. The contention resolution message indicates an uplink positioning configuration and a preconfigured uplink resource (PUR) configuration (i.e., uplink time and / or frequency resources allocated for uplink transmission) for the positioning session. Because the contention resolution message includes the uplink positioning configuration, the UE 1104 does not need to transition to an RRC CONNECTED state (if it is only performing the four-step random access procedure 1100 to obtain a positioning configuration for transmission of the UL-PRS). Thus, the UE 1104 can remain in an RRC IDLE state or an INACTIVE state even after completion of the four-step random access procedure 1100. As can be appreciated, this reduces latency and power consumption at the UE 1104.

[0154] 12 illustrates an example two-step random access procedure 1200 according to an aspect of the present disclosure. The two-step random access procedure 1200 is performed between a UE 1204 and a base station 1202 (illustrated as a gNB), which may correspond to any of the UEs and base stations, respectively, described herein.

[0155] The UE 1204 is in an RRC IDLE or INACTIVE state when a positioning event is detected at 1210. The positioning event may be, for example, a request for the UE 1204 to transmit an uplink positioning reference signal (e.g., a positioning SRS). The request may be received from a location server (e.g., location server 230, LMF 270, SLP 272), a third-party application, an external client, etc.

[0156] At 1220, the UE 1204 selects a positioning preamble (including a RACH positioning sequence) from the positioning preambles broadcast by the base station 1002 in one or more positioning SIBs. At 1230, the UE 1204 sends MsgA to the base station 1202, as in 610 of FIG. 6. MsgA includes the selected positioning preamble, thereby indicating to the base station 1202 that the UE 1204 is involved in a positioning session and that uplink positioning resources need to be configured for the positioning session.

[0157] At 1240, the base station 1202 is aware that the UE 1204 will be involved in a positioning session based on the reception of the positioning preamble at 1230. Accordingly, the base station 1202 determines an uplink positioning configuration that the UE 1204 should use to transmit an uplink positioning reference signal (UL-PRS) for the positioning session. At 1250, the base station 1202 sends a MsgB to the UE 1204, as in 620 of FIG. 6. The MsgB indicates the uplink positioning configuration and PUR resources for the positioning session. Because the MsgB includes the uplink positioning configuration, the UE 1204 does not need to transition to an RRC CONNECTED state (if it is only performing the two-step random access procedure 1200 to obtain the positioning configuration for transmission of the UL-PRS). As can be appreciated, this reduces latency and power consumption at the UE 1204.

[0158] The above describes a UE-initiated positioning session that may be triggered while the UE is in an RRC IDLE or RRC INACTIVE state. However, in some cases, the network (e.g., a location server, a serving base station, a third-party client, etc.) may initiate the positioning session and may do so while the UE is in an RRC IDLE or RRC INACTIVE state. Alternatively or additionally, during a positioning session, whether UE-initiated or network-initiated, the UE may go through multiple cycles of RRC IDLE, INACTIVE, and CONNECTED modes (e.g., as in the case of a long location tracking session). For every transition from IDLE mode to CONNECTED mode and from INACTIVE mode to CONNECTED mode, the UE needs to perform a random access procedure. The serving base station may not be aware that a positioning session is ongoing, and therefore its decision of whether to assign a dedicated preamble (as in CFRA) is independent of the positioning session and positioning requirements. That is, the serving base station can choose either CBRA or CFRA for the UE without any knowledge of the ongoing positioning session, let alone the requirements of the positioning session.

[0159] Thus, the present disclosure provides techniques for a location server to inform a serving base station about a positioning session and its importance. For example, the location server may indicate that the positioning session has normal latency requirements or that the positioning session must meet Ultra Reliable Low Latency Communication (URLLC) requirements. The location server may provide this information, for example, as an end-to-end latency value or a latency classification (e.g., “normal,” “URLLC,” etc.). The location server may provide this information to the base station in one or more LPP Type A (LPPa) or NR Positioning Protocol Type A (NRPPa) messages.

[0160] Based on the latency requirements of the positioning session, the base station is expected to assign a dedicated preamble for positioning to enable the UE to perform CFRA. As with the normal preamble, the dedicated preamble can be assigned to the UE via RRC signaling for transition from an IDLE state to a CONNECTED RRC state. Similarly, as with the normal preamble, the dedicated preamble can be assigned to the UE via physical layer signaling (e.g., DCI on the PDCCH) for transition from an INACTIVE state to a CONNECTED RRC state.

[0161] 13 illustrates an example three-step random access procedure 1300 according to an aspect of the present disclosure. The three-step random access procedure 1300 is performed between a UE 1304 and a base station 1302 (illustrated as a gNB), which may correspond to any of the UEs and base stations, respectively, described herein.

[0162] At 1310, the UE 1304 is in an RRC IDLE or INACTIVE state when a positioning event is detected at the base station 1302. The positioning event may be, for example, a request for the base station 1302 to allocate uplink or downlink positioning resources to the UE 1304. The request may be received from a location server (e.g., location server 230, LMF 270, SLP 272).

[0163] At 1320, the base station 1302 selects a positioning preamble (including a RACH positioning sequence) from dedicated / reserved positioning preambles. At 1330, the base station 1302 sends a preamble assignment to the UE 1304, as in 710 of FIG. 7. At 1340, the UE 1304 determines that the assigned preamble is a positioning preamble. At 1350, the UE 1304 sends a random access request (Msg1) to the base station 1302, as in 720 of FIG. 7. The random access request includes the assigned positioning preamble.

[0164] At 1340, the base station 1302 responds to the UE 1304 with a random access response (Msg2), as in 730 of FIG. 7. The random access response indicates an uplink positioning configuration and PUR resources for the positioning session. Because the random access response includes the uplink positioning configuration, the UE 1304 does not need to transition to an RRC CONNECTED state (if it is only performing the three-step random access procedure 1300 to obtain a positioning configuration for transmission of the UL-PRS). Thus, the UE 1304 can remain in an RRC IDLE state or an INACTIVE state even after completion of the three-step random access procedure 1300. As can be appreciated, this reduces latency and power consumption at the UE 1304.

[0165] After receiving the positioning configuration in the final step of the random access procedures 1100, 1200, and 1300, each UE may transmit an uplink positioning signal (eg, a positioning SRS) on the allocated resources.

[0166] 14 illustrates an example method 1400 for wireless communication according to an aspect of the present disclosure. In one aspect, the method 1400 may be performed by a UE (e.g., any of the UEs described herein).

[0167] At 1410, the UE determines at least one RACH preamble from a first set of RACH preambles, such as at 1120 in FIG. 11 , 1220 in FIG. 12 , or 1330 in FIG. 13 . In one aspect, the first set of RACH preambles is for positioning purposes, and the second set of RACH preambles is for communication purposes. The first set of RACH preambles and the second set of RACH preambles may be reserved for positioning and communication purposes, respectively, or one or both sets may be used for positioning and communication purposes. For example, if there are no available preambles in the first set of RACH preambles (because all are in use), one or more preambles in the second set of RACH preambles may be used for positioning. Similarly, if there are no available preambles in the second set of RACH preambles (because all are in use), one or more preambles in the first set of RACH preambles may be used for communication. In one aspect, the first set of RACH preambles and the second set of RACH preambles are associated with at least one TRP. In one aspect, operation 1410 may be performed by WWAN transceiver 310, processing system 332, memory component 340, and / or positioning component 342, any or all of which may be considered a means for performing this operation.

[0168] At 1420, the UE transmits at least one RACH preamble to at least one TRP (e.g., the TRP of any of the base stations described herein) to indicate that the UE will engage in a positioning session, such as at 1130 of Figure 11, 1230 of Figure 12, or 1350 of Figure 13. In one aspect, operation 1420 may be performed by the WWAN transceiver 310, the processing system 332, the memory component 340, and / or the positioning component 342, any or all of which may be considered a means for performing this operation.

[0169] At 1430, the UE receives from the at least one TRP an allocation of one or more resources for transmission of uplink positioning signals (e.g., SRS for positioning) for the positioning session in response to transmitting the at least one RACH preamble at 1420, such as at 1170 of Figure 11, 1250 of Figure 12, or 1360 of Figure 13. In one aspect, operation 1430 may be performed by the WWAN transceiver 310, the processing system 332, the memory component 340, and / or the positioning component 342, any or all of which may be considered a means for performing this operation.

[0170] The UE transmits the uplink positioning signal over one or more resources at 1440. In one aspect, operation 1440 may be performed by the WWAN transceiver 310, the processing system 332, the memory component 340, and / or the positioning component 342, any or all of which may be considered a means for performing this operation.

[0171] 15 illustrates an example method 1500 of wireless communication according to an aspect of the present disclosure. In one aspect, the method 1500 may be performed by a TRP (e.g., the TRP of any of the base stations described herein).

[0172] At 1510, the TRP transmits an indication of at least one RACH preamble of the first set of RACH preambles. In one aspect, the first set of RACH preambles is for positioning purposes, and the second set of RACH preambles is for communication purposes. The first set of RACH preambles and the second set of RACH preambles may be reserved for positioning and communication purposes, respectively, or one or both sets may be used for positioning and communication purposes. For example, if there are no available preambles in the first set of RACH preambles (because they are all in use), one or more preambles in the second set of RACH preambles may be used for positioning. Similarly, if there are no available preambles in the second set of RACH preambles (because they are all in use), one or more preambles in the first set of RACH preambles may be used for communication. In one aspect, the first set of RACH preambles and the second set of RACH preambles are associated with the TRP. In one aspect, operation 1510 may be performed by WWAN transceiver 350, processing system 384, memory component 386, and / or positioning component 388, any or all of which may be considered a means for performing this operation.

[0173] At 1520, the TRP receives at least one RACH preamble from a UE (e.g., any of the UEs described herein), such as at 1130 of Figure 11, 1230 of Figure 12, or 1350 of Figure 13. In one aspect, operation 1520 may be performed by WWAN transceiver 350, processing system 384, memory component 386, and / or positioning component 388, any or all of which may be considered means for performing this operation.

[0174] At 1530, the TRP transmits to the UE an allocation of one or more resources for transmission of uplink positioning signals for a positioning session involving the UE in response to receiving the at least one RACH preamble at 1520, such as at 1170 of Figure 11, 1250 of Figure 12, or 1360 of Figure 13. In one aspect, operation 1530 may be performed by WWAN transceiver 350, processing system 384, memory component 386, and / or positioning component 388, any or all of which may be considered a means for performing this operation.

[0175] As will be appreciated, technical advantages of methods 1400 and 1500 include reduced latency for positioning sessions, better multiplexing of RACH resources between different use cases (e.g., communication and positioning), and lower collision probability.

[0176] In the above detailed description, it can be seen that various features are grouped together in the examples. This manner of disclosure should not be understood as an intention that the example clauses have more features than are expressly recited in each clause. Rather, various aspects of the present disclosure may include fewer than all features of each example clause disclosed. Accordingly, the following clauses are hereby considered to be incorporated into this description, and each clause may stand alone as a separate example. Although each dependent clause may refer to a specific combination with one of the other clauses within that clause, the aspects of that dependent clause are not limited to that specific combination. It will be appreciated that other example clauses can also include combinations of aspects of that dependent clause with the subject matter of any other dependent clause or independent clause, or combinations of any features with other dependent clauses and independent clauses. The various aspects disclosed herein expressly include combinations of these combinations unless a particular combination is expressly expressed or can be readily inferred (e.g., contradictory aspects, such as defining an element as both an insulator and a conductor). It is further contemplated that aspects of a clause may be included within any other independent clause, even if the clause is not directly dependent on the independent clause.

[0177] Example implementations are described in the following numbered clauses.

[0178] Clause 1. A method of wireless communications performed by a user equipment (UE), comprising: determining at least one Random Access Channel (RACH) preamble from a first set of RACH preambles, the first set of RACH preambles being for positioning purposes and a second set of RACH preambles being for communication purposes, the first set of RACH preambles and the second set of RACH preambles being associated with at least one Transmit Reception Point (TRP); transmitting the at least one RACH preamble to the at least one TRP to indicate that the UE is involved in a positioning session; receiving, in response to transmitting the at least one RACH preamble, from the at least one TRP an allocation of one or more resources for transmission of an uplink positioning signal for the positioning session; and transmitting the uplink positioning signal via the one or more resources.

[0179] Clause 2. The method of clause 1, wherein the UE is in a radio resource control (RRC) idle state or an RRC inactive state when the UE transmits at least one RACH preamble, receives the allocation, and transmits the uplink positioning signal.

[0180] Clause 3. Any of the methods of clauses 1-2, wherein the allocation is received in the fourth message of a four-step RACH procedure.

[0181] Clause 4. The method of clause 3, wherein determining comprises receiving a system information block (SIB) from at least one TRP indicating at least a first set of RACH preambles; and selecting at least one RACH preamble from the first set of RACH preambles.

[0182] Clause 5. Any of the methods of clauses 1-2, wherein the allocation is received in a second message of a two-step RACH procedure.

[0183] Clause 6. The method of clause 5, wherein determining comprises receiving, from at least one TRP, an assignment of at least one RACH preamble from a first set of RACH preambles.

[0184] Clause 7. The method of clause 6, wherein in response to receiving the assignment, the UE transmits at least one RACH preamble.

[0185] Clause 8. The method of any of clauses 6-7, wherein receiving an assignment of at least one RACH preamble from the first set of RACH preambles indicates that the UE will engage in a positioning session.

[0186] Clause 9. The method of any of clauses 6 to 8, wherein the UE is in an RRC idle state and the UE receives the allocation in RRC signaling.

[0187] Clause 10. The method of any of clauses 6 to 8, wherein the UE is in an RRC inactive state and the UE receives the allocation in physical layer signaling.

[0188] Clause 11. The method of any of clauses 1-10, further comprising receiving a pre-configured uplink resource (PUR) configuration from at least one TRP.

[0189] Clause 12. The method of clause 11, wherein the PUR configuration is received in a fourth message of a four-step RACH procedure or a second message of a two-step RACH procedure.

[0190] Clause 13. The method of any of clauses 1 to 12, wherein the first set of RACH preambles and the second set of RACH preambles are all RACH preambles associated with at least one TRP for network access.

[0191] Clause 14. The method of any of clauses 1 to 13, wherein the first set of RACH preambles and the second set of RACH preambles total 64 preambles.

[0192] Clause 15. The method of any of clauses 1 to 14, wherein a third set of RACH preambles associated with at least one TRP is reserved for critical communications.

[0193] Clause 16. The method of clause 15, wherein the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles total 64 preambles.

[0194] Clause 17. A method of wireless communications performed by a transmit receiving point (TRP), comprising: transmitting an indication of at least one Random Access Channel (RACH) preamble of a first set of RACH preambles, the first set of RACH preambles being for positioning purposes and a second set of RACH preambles being for communication purposes, the first set of RACH preambles and the second set of RACH preambles being associated with the TRP; receiving at least one RACH preamble from a user equipment (UE) from the first set of RACH preambles; and transmitting to the UE, in response to receiving the at least one RACH preamble, an allocation of one or more resources for transmission of uplink positioning signals for a positioning session involving the UE.

[0195] Clause 18. The method of clause 17, wherein the UE is in a radio resource control (RRC) idle state or an RRC inactive state when the TRP receives at least one RACH preamble and sends the allocation.

[0196] Clause 19. Any of the methods of clauses 17-18, wherein the allocation is transmitted in the fourth message of the four-step RACH procedure.

[0197] Clause 20. The method of clause 19, wherein transmitting the indication comprises broadcasting a system information block (SIB) indicating at least the first set of RACH preambles.

[0198] Clause 21. The method of clause 20, wherein reception of at least one RACH preamble from the first set of RACH preambles indicates that the UE is engaged in a positioning session.

[0199] Clause 22. Any of the methods of clauses 17-18, wherein the allocation is transmitted in a second message of a two-step RACH procedure.

[0200] Clause 23. The method of clause 22, wherein transmitting the indication comprises transmitting to the UE an assignment of at least one RACH preamble from a first set of RACH preambles.

[0201] Clause 24. The method of clause 23, wherein the UE is in an RRC idle state and the TRP sends the allocation in RRC signaling.

[0202] Clause 25. The method of clause 23, wherein the UE is in an RRC inactive state and the TRP sends the allocation in physical layer signaling.

[0203] Clause 26. The method of any of clauses 23 to 25, further comprising detecting that the UE is to be involved in a positioning session, wherein the TRP transmits the allocation in response to detecting that the UE is to be involved in the positioning session.

[0204] Clause 27. The method of clause 26, wherein the TRP detects that the UE is involved in a positioning session based on receiving a request from the location server to allocate positioning resources to the UE.

[0205] Clause 28. The method of clause 27, wherein the request from the location server comprises a Long Term Evolution (LTE) Positioning Protocol (LPP) Type A (LPPa) request.

[0206] Clause 29. The method of any of clauses 27-28, wherein the request includes a latency requirement for the positioning session.

[0207] Clause 30. The method of clause 29, wherein the latency requirement comprises an indication that the positioning session has normal latency, an indication that the positioning session is for ultra-reliable low latency (URLL) communication, or an indication of an end-to-end latency for the positioning session.

[0208] Clause 31. The method of any of clauses 17-30, further comprising transmitting a pre-configured uplink resource (PUR) configuration to the UE.

[0209] Clause 32. The method of clause 31, wherein the PUR configuration is transmitted in a fourth message of a four-step RACH procedure or a second message of a two-step RACH procedure.

[0210] Clause 33. The method of any of clauses 17 to 32, wherein the first set of RACH preambles and the second set of RACH preambles are all RACH preambles associated with a TRP for network access.

[0211] Clause 34. The method of any of clauses 17 to 33, wherein the first set of RACH preambles and the second set of RACH preambles total 64 preambles.

[0212] Clause 35. The method of any of clauses 17 to 34, wherein a third set of RACH preambles associated with the TRP is reserved for critical communications.

[0213] Clause 36. The method of clause 35, wherein the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles total 64 preambles.

[0214] Clause 37. An apparatus comprising a memory and at least one processor communicatively coupled to the memory, wherein the memory and the at least one processor are configured to perform a method according to any of clauses 1 to 36.

[0215] Clause 38. Apparatus comprising means for carrying out the method according to any of clauses 1 to 36.

[0216] Clause 39. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising at least one instruction for causing a computer or processor to perform a method according to any of clauses 1 to 36.

[0217] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0218] Furthermore, those skilled in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0219] The various example logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed using 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. A general-purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., 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.

[0220] The methods, sequences, and / or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in software modules executed by a processor, or in a combination of the two. The software modules 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, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). Alternatively, the processor and the storage medium may reside as discrete components in the user terminal.

[0221] In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media, including any medium that facilitates transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media may 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. Also, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included within the definition of medium. Disk and disc, as used herein, include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks, and Blu-ray discs, where disks typically reproduce data magnetically and discs reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0222] While the above disclosure illustrates exemplary aspects of the present disclosure, it should be noted that various changes and modifications can be made herein without departing from the scope of the present disclosure as defined by the appended claims. The functions, steps, and / or actions of the method claims in accordance with the aspects of the present disclosure described herein need not be performed in any particular order. Furthermore, although elements of the present disclosure may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. [Explanation of symbols]

[0223] 100 Wireless Communication System 102 Base station 104 User Equipment (UE) 110 Coverage Area 112 Space Vehicle (SV) 120 Communication Links 122 backhaul links 134 backhaul links 150 Wireless Local Area Network (WLAN) Access Points (APs) 152 Wireless Local Area Network (WLAN) Station (STA) 154 communication links 164 User Equipment (UE) 170 Core Network 172 Location Server 180 mmW base station 182 User Equipment (UE) 184 Millimeter Wave (mmW) Communication Link 190 User Equipment (UE) 192, 194 Device-to-Device (D2D) Peer-to-Peer (P2P) Links 200 Wireless Network Structure 204 User Equipment (UE) 210 5G Core (5GC) 212 User Plane Functions 213 User Plane Interface (NG-U) 214 Control Plane Functions 215 Control Plane Interface (NG-C) 220 New RAN 222 gNB 223 Backhaul Connection 224 ng-eNB 230 Location Server 250 Wireless Network Structure 260 5G Core (5GC) 262 User Plane Function (UPF) 263 User Plane Interface 264 Access and Mobility Management Function (AMF) 265 Control Plane Interface 266 Session Management Facility (SMF) 270 Location Management Function (LMF) 272 Secure User Plane Location (SUPL) Location Platform (SLP) 302 User Equipment (UE) 304 base station 306 Network Entity 310 Wireless Wide Area Network (WWAN) Transceiver 312 Receiver 314 Transmitter 316 Antenna 318 Signal 320 Wireless Local Area Network (WLAN) Transceiver 322 Receiver 324 Transmitter 326 Antenna 328 signal 330 Satellite Positioning System (SPS) Receiver 332 Processing System 334 Data Bus 336 Antenna 338 Satellite Positioning System (SPS) signals 340 Memory Components 342 Positioning Components 344 Sensors 346 User Interface 350 Wireless Wide Area Network (WWAN) Transceiver 352 receiver 354 Transmitter 356 Antenna 358 Signal 360 Wireless Local Area Network (WLAN) Transceiver 362 Receiver 364 Transmitter 366 Antenna 368 signal 370 Satellite Positioning System (SPS) Receiver 376 Antenna 378 Satellite Positioning System (SPS) signals 380 Network Interface 382 Data Bus 384 Processing Systems 386 Memory Components 388 Positioning Components 390 Network Interface 392 Data Bus 394 Processing Systems 396 Memory Components 398 Positioning Components 500 4-Step Random Access Procedure 502 base station 504 User Equipment (UE) 600 Two-Step Random Access Procedure 602 Base Station 604 User Equipment (UE) 700 3-Step Random Access Procedure 702 base station 704 User Equipment (UE) 900 RACH Preamble 910 Cyclic Prefix (CP) 920 Preamble Sequence 930 Guard Period (GP) 1100 4-Step Random Access Procedure 1102 base station 1104 User Equipment (UE) 1200 Two-Step Random Access Procedure 1202 base station 1204 User Equipment (UE) 1300 3-Step Random Access Procedure 1302 base station 1304 User Equipment (UE)

Claims

1. 1. A method of wireless communication performed by a user equipment (UE), comprising: determining at least one Random Access Channel (RACH) preamble from a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes, a second set of RACH preambles is for communication purposes, and a third set of RACH preambles is reserved for critical communications, the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles are associated with at least one Transmit Reception Point (TRP), and a total of 64 RACH preambles are provided; transmitting the at least one RACH preamble to the at least one TRP to indicate that the UE is involved in a positioning session; receiving, in response to transmitting the at least one RACH preamble, an allocation of one or more resources for transmission of uplink positioning signals for the positioning session from the at least one TRP; transmitting the uplink positioning signal over the one or more resources; A method for providing the above.

2. 2. The method of claim 1, wherein the UE is in a radio resource control (RRC) idle state or an RRC inactive state when the UE transmits the at least one RACH preamble, receives the allocation, and transmits the uplink positioning signal.

3. 2. The method of claim 1, wherein the allocation is received in a fourth message of a four-step RACH procedure, or wherein the allocation is received in a second message of a two-step RACH procedure.

4. The allocation is received in a fourth message of a four-step RACH procedure; the determining step: receiving a system information block (SIB) from the at least one TRP indicating at least the first set of RACH preambles; selecting the at least one RACH preamble from the first set of RACH preambles. The method of claim 1.

5. The allocation is received in a second message of a two-step RACH procedure; the determining step: receiving an assignment of the at least one RACH preamble from the first set of RACH preambles from the at least one TRP. The method of claim 1.

6. transmitting the at least one RACH preamble by the UE in response to receiving the assignment. receiving the assignment of the at least one RACH preamble from the first set of RACH preambles indicates that the UE is involved in the positioning session. the UE is in an RRC idle state and the UE receives the assignment in RRC signaling; or the UE is in an RRC inactive state and the UE receives the assignment in physical layer signaling; The method of claim 5.

7. receiving a pre-configured uplink resource (PUR) configuration from the at least one TRP; 10. The method of claim 1, further comprising: wherein the PUR configuration is received in a fourth message of a four-step RACH procedure or a second message of a two-step RACH procedure.

8. 2. The method of claim 1, wherein the first set of RACH preambles and the second set of RACH preambles are all RACH preambles associated with the at least one TRP for network access.

9. 1. A method of wireless communication performed by a Transmit Receiving Point (TRP), comprising: transmitting an indication of at least one Random Access Channel (RACH) preamble of a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes, a second set of RACH preambles is for communication purposes, and a third set of RACH preambles is reserved for critical communications, the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles are associated with the TRP, and a total of 64 RACH preambles are provided for the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles; receiving the at least one RACH preamble from the first set of RACH preambles from a user equipment (UE); transmitting, in response to receiving the at least one RACH preamble, to the UE an allocation of one or more resources for transmission of uplink positioning signals for a positioning session involving the UE; A method for providing the above.

10. 10. The method of claim 9, wherein the UE is in a radio resource control (RRC) idle state or an RRC inactive state when the TRP receives the at least one RACH preamble and sends the allocation.

11. the allocation is sent in a fourth message of a four-step RACH procedure; wherein the transmitting the indication comprises broadcasting a system information block (SIB) indicating at least the first set of RACH preambles; 10. The method of claim 9, wherein reception of the at least one RACH preamble from the first set of RACH preambles indicates that the UE is involved in the positioning session.

12. the allocation being transmitted in a second message of a two-step RACH procedure; wherein the step of transmitting the indication comprises transmitting to the UE an assignment of the at least one RACH preamble from the first set of RACH preambles. The UE is in an RRC idle state and the TRP sends the assignment in RRC signaling; or 10. The method of claim 9, wherein the UE is in an RRC inactive state and the TRP sends the allocation in physical layer signaling.

13. The method of claim 12, wherein the step of transmitting the indication comprises the step of transmitting to the UE an assignment of the at least one RACH preamble from the first set of RACH preambles; detecting that the UE will be involved in the positioning session, wherein the TRP sends the assignment in response to detecting that the UE will be involved in the positioning session. the TRP detecting that the UE is involved in the positioning session based on receiving a request from a location server to allocate positioning resources to the UE; the request from the location server comprises a Long Term Evolution (LTE) Positioning Protocol (LPP) Type A (LPPa) request; and / or the request includes a latency requirement for the positioning session; The latency requirement is: an indication that the positioning session has normal latency; an indication that the positioning session is for Ultra Reliable Low Latency (URLL) communications; or an indication of end-to-end latency for the positioning session; The method of claim 12.

14. transmitting a pre-configured uplink resource (PUR) configuration to the UE. The PUR configuration is sent in the fourth message of a four-step RACH procedure or the second message of a two-step RACH procedure, or the first set of RACH preambles and the second set of RACH preambles are all RACH preambles associated with the TRP for network access; The method of claim 9.

15. A user equipment (UE), Memory and at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor: determining at least one Random Access Channel (RACH) preamble from a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes, a second set of RACH preambles is for communication purposes, and a third set of RACH preambles is reserved for critical communications, the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles are associated with at least one Transmit Reception Point (TRP), and a total of 64 RACH preambles are provided for the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles; causing the at least one transceiver to transmit the at least one RACH preamble to the at least one TRP to indicate that the UE is involved in a positioning session; receiving, in response to transmitting the at least one RACH preamble, an allocation of one or more resources for transmission of uplink positioning signals for the positioning session from the at least one TRP; and causing the at least one transceiver to transmit the uplink positioning signal over the one or more resources. User equipment.

16. A UE as described in claim 15, wherein the at least one processor is further configured to execute a method described in any one of claims 2 to 8.

17. A transmit receiving point (TRP), comprising: Memory and at least one transceiver; and at least one processor communicatively coupled to the memory and the at least one transceiver, the at least one processor: causing the at least one transceiver to transmit an indication of at least one Random Access Channel (RACH) preamble of a first set of RACH preambles, wherein the first set of RACH preambles is for positioning purposes, a second set of RACH preambles is for communication purposes, and a third set of RACH preambles is reserved for critical communications, the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles are associated with the TRP, and a total of 64 RACH preambles are provided for the first set of RACH preambles, the second set of RACH preambles, and the third set of RACH preambles; receiving the at least one RACH preamble from the first set of RACH preambles from a user equipment (UE); and causing the at least one transceiver to transmit to the UE, in response to receiving the at least one RACH preamble, an allocation of one or more resources for transmission of uplink positioning signals for a positioning session involving the UE. Send-receive points.

18. A TRP as described in claim 17, wherein the one or more processors are further configured to execute a method as described in any one of claims 10 to 14.

19. A non-transitory computer-readable medium storing computer-executable instructions, the computer-executable instructions comprising: At least one instruction for instructing a user equipment (UE) to perform the method according to any one of claims 1 to 8; or At least one instruction instructing a Transmit Receive Point (TRP) to perform the method according to any one of claims 9 to 14.

1. A non-transitory computer-readable medium comprising:

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