WO2022031457A1 - Physical random access channel for new radio positioning - Google Patents

Abstract

An apparatus and system to provide positioning information during a PRACH procedure, as well as the PRACH structure are described. For a two-step PRACH procedure, the UE sends a PRACH preamble, msgA payload, and UL SRS to a gNB, and the gNB in response responds with a msgB payload and a DL PRS. The gNB also provides an UL and DL PRS configuration that respectively indicates a time domain offset of an SRS slot relative to a PRACH slot and a number of successive time slots occupied by the UL SRS and a time domain offset of a DL PRS slot relative to a msgB slot and a number of successive time slots occupied by the DL PRS.

Description

PHYSICAL RANDOM ACCESS CHANNEL FOR NEW RADIO POSITIONING PRIORITY CLAIM [0001] This application claims the benefit of priority to United States Provisional Patent Application Serial No. 63/061,685, filed August 5, 2020, and United States Provisional Patent Application Serial No. 63/061,688, filed August 5, 2020, each of which is incorporated herein by reference in its entirety. TECHNICAL FIELD [0002] Embodiments pertain to fifth generation (5G) wireless communications. In particular, some embodiments relate to the physical random access channel (PRACH) in 5G systems. BACKGROUND [0003] The use and complexity of wireless systems, which include 4^th generation (4G) and 5^th generation (5G) networks among others, has increased due to both an increase in the types of devices user equipment (UEs) using network resources as well as the amount of data and bandwidth being used by various applications, such as video streaming, operating on these UEs. With the vast increase in number and diversity of communication devices, the corresponding network environment, including routers, switches, bridges, gateways, firewalls, and load balancers, has become increasingly complicated, especially with the advent of next generation (NG) (or new radio (NR) systems). As expected, a number of issues abound with the advent of any new technology. BRIEF DESCRIPTION OF THE FIGURES [0004] In the figures, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The figures illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. [0005] FIG. 1A illustrates an architecture of a network, in accordance with some aspects. [0006] FIG. 1B illustrates a non-roaming 5G system architecture in accordance with some aspects. [0007] FIG. 1C illustrates a non-roaming 5G system architecture in accordance with some aspects. [0008] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments. [0009] FIG. 3 illustrates a 4-step RACH procedure in accordance with some embodiments. [0010] FIG. 4 illustrates a 2-step RACH procedure in accordance with some embodiments. [0011] FIG. 5 illustrates a time-frequency occasions configuration and system frame indexes counting for 5^th generation NodeBs (gNBs) in accordance with some embodiments. [0012] FIG. 6 illustrates a synchronization procedure between a UE and the gNBs in accordance with some embodiments. [0013] FIG. 7 illustrates a 2-step RACH procedure for positioning in accordance with some embodiments. [0014] FIG. 8 illustrates a 4-step RACH procedure for positioning in accordance with some embodiments. [0015] FIG. 9 illustrates another 2-step RACH procedure for positioning in accordance with some embodiments. [0016] FIG. 10 illustrates mapping between a PRACH time slot and uplink (UL) sounding reference signal (SRS) time slots in accordance with some embodiments. [0017] FIG. 11 illustrates mapping between a msgB time slot and a downlink (DL) positioning reference signal (PRS) time slot in accordance with some embodiments. [0018] FIG. 12 illustrates round trip time (RTT) estimations in accordance with some embodiments. [0019] FIG. 13 illustrates another 2-step RACH procedure in accordance with some embodiments. [0020] FIG. 14 illustrates PRACH time-domain occasions in accordance with some embodiments. [0021] FIG. 15 illustrates PRACH frequency-domain occasions in accordance with some embodiments. [0022] FIG. 16 illustrates a msgA physical uplink shared channel (PUSCH) transmission in accordance with some embodiments. [0023] FIG. 17 illustrates a msgA PUSCH time slot configuration in accordance with some embodiments. [0024] FIG. 18 illustrates msgA PUSCH frequency-domain occasions in accordance with some embodiments. [0025] FIG. 19 illustrates UL SRS time-domain occasions in accordance with some embodiments. [0026] FIG. 20 illustrates UL SRS frequency-domain occasions in accordance with some embodiments. [0027] FIG. 21A illustrates a first UL SRS transmission in accordance with some embodiments. [0028] FIG. 21B illustrates a second UL SRS transmission in accordance with some embodiments. [0029] FIG. 22A illustrates a first resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. [0030] FIG. 22B illustrates a second resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. [0031] FIG. 23A illustrates a third UL SRS transmission in accordance with some embodiments. [0032] FIG. 23B illustrates a fourth UL SRS transmission in accordance with some embodiments. [0033] FIG. 24A illustrates a third resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. [0034] FIG. 24B illustrates a fourth resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. [0035] FIG. 25 illustrates another mapping between a PRACH time slot and UL SRS time slots in accordance with some embodiments. [0036] FIG. 26A illustrates a first mapping between PRACH preamble time-domain occasions and UL SRS time-domain occasions in accordance with some embodiments. [0037] FIG. 26B illustrates a second mapping between PRACH preamble time-domain occasions and UL SRS time-domain occasions in accordance with some embodiments. [0038] FIG. 27 illustrates another resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. [0039] FIG. 28 illustrates a mapping between a msgA PUSCH first time slot and UL SRS time slots in accordance with some embodiments. [0040] FIG. 29A illustrates a first mapping between msgA PUSCH time- domain occasions and UL SRS time-domain occasions in accordance with some embodiments. [0041] FIG. 29B illustrates a second mapping between msgA PUSCH time-domain occasions and UL SRS time-domain occasions in accordance with some embodiments. [0042] FIG. 30 illustrates resource mapping between msgA PUSCH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. [0043] FIG. 31 illustrates DL PRS time-domain occasions in accordance with some embodiments. [0044] FIG. 32 illustrates DL PRS frequency-domain occasions in accordance with some embodiments. [0045] FIG. 33 illustrates mapping between msgB time slot and DL PRS time slot in accordance with some embodiments. [0046] FIG. 34 illustrates a DL PRS signal structure in accordance with some embodiments. [0047] FIG. 35 illustrates a DL PRS transmission using multiple time slots and multiple time-domain occasions in accordance with some embodiments. DETAILED DESCRIPTION [0048] The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. [0049] FIG. 1A illustrates an architecture of a network in accordance with some aspects. The network 140A includes 3GPP LTE/4G and NG network functions that may be extended to 6G functions. Accordingly, although 5G will be referred to, it is to be understood that this is to extend as able to 6G structures, systems, and functions. A network function can be implemented as a discrete network element on a dedicated hardware, as a software instance running on dedicated hardware, and/or as a virtualized function instantiated on an appropriate platform, e.g., dedicated hardware or a cloud infrastructure. [0050] The network 140A is shown to include user equipment (UE) 101 and UE 102. The UEs 101 and 102 are illustrated as smartphones (e.g., handheld touchscreen mobile computing devices connectable to one or more cellular networks) but may also include any mobile or non-mobile computing device, such as portable (laptop) or desktop computers, wireless handsets, drones, or any other computing device including a wired and/or wireless communications interface. The UEs 101 and 102 can be collectively referred to herein as UE 101, and UE 101 can be used to perform one or more of the techniques disclosed herein. [0051] Any of the radio links described herein (e.g., as used in the network 140A or any other illustrated network) may operate according to any exemplary radio communication technology and/or standard. Any spectrum management scheme including, for example, dedicated licensed spectrum, unlicensed spectrum, (licensed) shared spectrum (such as Licensed Shared Access (LSA) in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz, and other frequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and other frequencies). Different Single Carrier or Orthogonal Frequency Domain Multiplexing (OFDM) modes (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-based multicarrier (FBMC), OFDMA, etc.), and in particular 3GPP NR, may be used by allocating the OFDM carrier data bit vectors to the corresponding symbol resources. [0052] In some aspects, any of the UEs 101 and 102 can comprise an Internet-of-Things (IoT) UE or a Cellular IoT (CIoT) UE, which can comprise a network access layer designed for low-power IoT applications utilizing short- lived UE connections. In some aspects, any of the UEs 101 and 102 can include a narrowband (NB) IoT UE (e.g., such as an enhanced NB-IoT (eNB-IoT) UE and Further Enhanced (FeNB-IoT) UE). An IoT UE can utilize technologies such as machine-to-machine (M2M) or machine-type communications (MTC) for exchanging data with an MTC server or device via a public land mobile network (PLMN), Proximity-Based Service (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC exchange of data may be a machine-initiated exchange of data. An IoT network includes interconnecting IoT UEs, which may include uniquely identifiable embedded computing devices (within the Internet infrastructure), with short-lived connections. The IoT UEs may execute background applications (e.g., keep- alive messages, status updates, etc.) to facilitate the connections of the IoT network. In some aspects, any of the UEs 101 and 102 can include enhanced MTC (eMTC) UEs or further enhanced MTC (FeMTC) UEs. [0053] The UEs 101 and 102 may be configured to connect, e.g., communicatively couple, with a radio access network (RAN) 110. The RAN 110 may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. [0054] The UEs 101 and 102 utilize connections 103 and 104, respectively, each of which comprises a physical communications interface or layer (discussed in further detail below); in this example, the connections 103 and 104 are illustrated as an air interface to enable communicative coupling, and can be consistent with cellular communications protocols, such as a Global System for Mobile Communications (GSM) protocol, a code-division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a 5G protocol, a 6G protocol, and the like. [0055] In an aspect, the UEs 101 and 102 may further directly exchange communication data via a ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a sidelink (SL) interface comprising one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel (PSSCH), a Physical Sidelink Discovery Channel (PSDCH), a Physical Sidelink Broadcast Channel (PSBCH), and a Physical Sidelink Feedback Channel (PSFCH). [0056] The UE 102 is shown to be configured to access an access point (AP) 106 via connection 107. The connection 107 can comprise a local wireless connection, such as, for example, a connection consistent with any IEEE 802.11 protocol, according to which the AP 106 can comprise a wireless fidelity (WiFi®) router. In this example, the AP 106 is shown to be connected to the Internet without connecting to the core network of the wireless system (described in further detail below). [0057] The RAN 110 can include one or more access nodes that enable the connections 103 and 104. These access nodes (ANs) can be referred to as base stations (BSs), NodeBs, evolved NodeBs (eNBs), Next Generation NodeBs (gNBs), RAN nodes, and the like, and can comprise ground stations (e.g., terrestrial access points) or satellite stations providing coverage within a geographic area (e.g., a cell). In some aspects, the communication nodes 111 and 112 can be transmission/reception points (TRPs). In instances when the communication nodes 111 and 112 are NodeBs (e.g., eNBs or gNBs), one or more TRPs can function within the communication cell of the NodeBs. The RAN 110 may include one or more RAN nodes for providing macrocells, e.g., macro RAN node 111, and one or more RAN nodes for providing femtocells or picocells (e.g., cells having smaller coverage areas, smaller user capacity, or higher bandwidth compared to macrocells), e.g., low power (LP) RAN node 112. [0058] Any of the RAN nodes 111 and 112 can terminate the air interface protocol and can be the first point of contact for the UEs 101 and 102. In some aspects, any of the RAN nodes 111 and 112 can fulfill various logical functions for the RAN 110 including, but not limited to, radio network controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management. In an example, any of the nodes 111 and/or 112 can be a gNB, an eNB, or another type of RAN node. [0059] The RAN 110 is shown to be communicatively coupled to a core network (CN) 120 via an S1 interface 113. In aspects, the CN 120 may be an evolved packet core (EPC) network, a NextGen Packet Core (NPC) network, or some other type of CN (e.g., as illustrated in reference to FIGS. 1B-1C). In this aspect, the S1 interface 113 is split into two parts: the S1-U interface 114, which carries traffic data between the RAN nodes 111 and 112 and the serving gateway (S-GW) 122, and the S1-mobility management entity (MME) interface 115, which is a signaling interface between the RAN nodes 111 and 112 and MMEs 121. [0060] In this aspect, the CN 120 comprises the MMEs 121, the S-GW 122, the Packet Data Network (PDN) Gateway (P-GW) 123, and a home subscriber server (HSS) 124. The MMEs 121 may be similar in function to the control plane of legacy Serving General Packet Radio Service (GPRS) Support Nodes (SGSN). The MMEs 121 may manage mobility aspects in access such as gateway selection and tracking area list management. The HSS 124 may comprise a database for network users, including subscription-related information to support the network entities' handling of communication sessions. The CN 120 may comprise one or several HSSs 124, depending on the number of mobile subscribers, on the capacity of the equipment, on the organization of the network, etc. For example, the HSS 124 can provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location dependencies, etc. [0061] The S-GW 122 may terminate the S1 interface 113 towards the RAN 110, and routes data packets between the RAN 110 and the CN 120. In addition, the S-GW 122 may be a local mobility anchor point for inter-RAN node handovers and also may provide an anchor for inter-3GPP mobility. Other responsibilities of the S-GW 122 may include a lawful intercept, charging, and some policy enforcement. [0062] The P-GW 123 may terminate an SGi interface toward a PDN. The P-GW 123 may route data packets between the EPC network 120 and external networks such as a network including the application server 184 (alternatively referred to as application function (AF)) via an Internet Protocol (IP) interface 125. The P-GW 123 can also communicate data to other external networks 131A, which can include the Internet, IP multimedia subsystem (IPS) network, and other networks. Generally, the application server 184 may be an element offering applications that use IP bearer resources with the core network (e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). In this aspect, the P-GW 123 is shown to be communicatively coupled to an application server 184 via an IP interface 125. The application server 184 can also be configured to support one or more communication services (e.g., Voice-over- Internet Protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for the UEs 101 and 102 via the CN 120. [0063] The P-GW 123 may further be a node for policy enforcement and charging data collection. Policy and Charging Rules Function (PCRF) 126 is the policy and charging control element of the CN 120. In a non-roaming scenario, in some aspects, there may be a single PCRF in the Home Public Land Mobile Network (HPLMN) associated with a UE's Internet Protocol Connectivity Access Network (IP-CAN) session. In a roaming scenario with a local breakout of traffic, there may be two PCRFs associated with a UE's IP-CAN session: a Home PCRF (H-PCRF) within an HPLMN and a Visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF 126 may be communicatively coupled to the application server 184 via the P-GW 123. [0064] In some aspects, the communication network 140A can be an IoT network or a 5G or 6G network, including 5G new radio network using communications in the licensed (5G NR) and the unlicensed (5G NR-U) spectrum. One of the current enablers of IoT is the narrowband-IoT (NB-IoT). Operation in the unlicensed spectrum may include dual connectivity (DC) operation and the standalone LTE system in the unlicensed spectrum, according to which LTE-based technology solely operates in unlicensed spectrum without the use of an “anchor” in the licensed spectrum, called MulteFire. Further enhanced operation of LTE systems in the licensed as well as unlicensed spectrum is expected in future releases and 5G systems. Such enhanced operations can include techniques for sidelink resource allocation and UE processing behaviors for NR sidelink V2X communications. [0065] An NG system architecture (or 6G system architecture) can include the RAN 110 and a 5G network core (5GC) 120. The NG-RAN 110 can include a plurality of nodes, such as gNBs and NG-eNBs. The core network 120 (e.g., a 5G core network/5GC) can include an access and mobility function (AMF) and/or a user plane function (UPF). The AMF and the UPF can be communicatively coupled to the gNBs and the NG-eNBs via NG interfaces. More specifically, in some aspects, the gNBs and the NG-eNBs can be connected to the AMF by NG-C interfaces, and to the UPF by NG-U interfaces. The gNBs and the NG-eNBs can be coupled to each other via Xn interfaces. [0066] In some aspects, the NG system architecture can use reference points between various nodes. In some aspects, each of the gNBs and the NG- eNBs can be implemented as a base station, a mobile edge server, a small cell, a home eNB, and so forth. In some aspects, a gNB can be a master node (MN) and NG-eNB can be a secondary node (SN) in a 5G architecture. [0067] FIG. 1B illustrates a non-roaming 5G system architecture in accordance with some aspects. In particular, FIG. 1B illustrates a 5G system architecture 140B in a reference point representation, which may be extended to a 6G system architecture. More specifically, UE 102 can be in communication with RAN 110 as well as one or more other 5GC network entities. The 5G system architecture 140B includes a plurality of network functions (NFs), such as an AMF 132, session management function (SMF) 136, policy control function (PCF) 148, application function (AF) 150, UPF 134, network slice selection function (NSSF) 142, authentication server function (AUSF) 144, and unified data management (UDM)/home subscriber server (HSS) 146. [0068] The UPF 134 can provide a connection to a data network (DN) 152, which can include, for example, operator services, Internet access, or third- party services. The AMF 132 can be used to manage access control and mobility and can also include network slice selection functionality. The AMF 132 may provide UE-based authentication, authorization, mobility management, etc., and may be independent of the access technologies. The SMF 136 can be configured to set up and manage various sessions according to network policy. The SMF 136 may thus be responsible for session management and allocation of IP addresses to UEs. The SMF 136 may also select and control the UPF 134 for data transfer. The SMF 136 may be associated with a single session of a UE 101 or multiple sessions of the UE 101. This is to say that the UE 101 may have multiple 5G sessions. Different SMFs may be allocated to each session. The use of different SMFs may permit each session to be individually managed. As a consequence, the functionalities of each session may be independent of each other. [0069] The UPF 134 can be deployed in one or more configurations according to the desired service type and may be connected with a data network. The PCF 148 can be configured to provide a policy framework using network slicing, mobility management, and roaming (similar to PCRF in a 4G communication system). The UDM can be configured to store subscriber profiles and data (similar to an HSS in a 4G communication system). [0070] The AF 150 may provide information on the packet flow to the PCF 148 responsible for policy control to support a desired QoS. The PCF 148 may set mobility and session management policies for the UE 101. To this end, the PCF 148 may use the packet flow information to determine the appropriate policies for proper operation of the AMF 132 and SMF 136. The AUSF 144 may store data for UE authentication. [0071] In some aspects, the 5G system architecture 140B includes an IP multimedia subsystem (IMS) 168B as well as a plurality of IP multimedia core network subsystem entities, such as call session control functions (CSCFs). More specifically, the IMS 168B includes a CSCF, which can act as a proxy CSCF (P-CSCF) 162BE, a serving CSCF (S-CSCF) 164B, an emergency CSCF (E-CSCF) (not illustrated in FIG. 1B), or interrogating CSCF (I-CSCF) 166B. The P-CSCF 162B can be configured to be the first contact point for the UE 102 within the IM subsystem (IMS) 168B. The S-CSCF 164B can be configured to handle the session states in the network, and the E-CSCF can be configured to handle certain aspects of emergency sessions such as routing an emergency request to the correct emergency center or PSAP. The I-CSCF 166B can be configured to function as the contact point within an operator's network for all IMS connections destined to a subscriber of that network operator, or a roaming subscriber currently located within that network operator's service area. In some aspects, the I-CSCF 166B can be connected to another IP multimedia network 170E, e.g. an IMS operated by a different network operator. [0072] In some aspects, the UDM/HSS 146 can be coupled to an application server 160E, which can include a telephony application server (TAS) or another application server (AS). The AS 160B can be coupled to the IMS 168B via the S-CSCF 164B or the I-CSCF 166B. [0073] A reference point representation shows that interaction can exist between corresponding NF services. For example, FIG. 1B illustrates the following reference points: N1 (between the UE 102 and the AMF 132), N2 (between the RAN 110 and the AMF 132), N3 (between the RAN 110 and the UPF 134), N4 (between the SMF 136 and the UPF 134), N5 (between the PCF 148 and the AF 150, not shown), N6 (between the UPF 134 and the DN 152), N7 (between the SMF 136 and the PCF 148, not shown), N8 (between the UDM 146 and the AMF 132, not shown), N9 (between two UPFs 134, not shown), N10 (between the UDM 146 and the SMF 136, not shown), N11 (between the AMF 132 and the SMF 136, not shown), N12 (between the AUSF 144 and the AMF 132, not shown), N13 (between the AUSF 144 and the UDM 146, not shown), N14 (between two AMFs 132, not shown), N15 (between the PCF 148 and the AMF 132 in case of a non-roaming scenario, or between the PCF 148 and a visited network and AMF 132 in case of a roaming scenario, not shown), N16 (between two SMFs, not shown), and N22 (between AMF 132 and NSSF 142, not shown). Other reference point representations not shown in FIG. 1E can also be used. [0074] FIG. 1C illustrates a 5G system architecture 140C and a service- based representation. In addition to the network entities illustrated in FIG. 1B, system architecture 140C can also include a network exposure function (NEF) 154 and a network repository function (NRF) 156. In some aspects, 5G system architectures can be service-based and interaction between network functions can be represented by corresponding point-to-point reference points Ni or as service-based interfaces. [0075] In some aspects, as illustrated in FIG. 1C, service-based representations can be used to represent network functions within the control plane that enable other authorized network functions to access their services. In this regard, 5G system architecture 140C can include the following service- based interfaces: Namf 158H (a service-based interface exhibited by the AMF 132), Nsmf 158I (a service-based interface exhibited by the SMF 136), Nnef 158B (a service-based interface exhibited by the NEF 154), Npcf 158D (a service-based interface exhibited by the PCF 148), a Nudm 158E (a service- based interface exhibited by the UDM 146), Naf 158F (a service-based interface exhibited by the AF 150), Nnrf 158C (a service-based interface exhibited by the NRF 156), Nnssf 158A (a service-based interface exhibited by the NSSF 142), Nausf 158G (a service-based interface exhibited by the AUSF 144). Other service-based interfaces (e.g., Nudr, N5g-eir, and Nudsf) not shown in FIG. 1C can also be used. [0076] NR-V2X architectures may support high-reliability low latency sidelink communications with a variety of traffic patterns, including periodic and aperiodic communications with random packet arrival time and size. Techniques disclosed herein can be used for supporting high reliability in distributed communication systems with dynamic topologies, including sidelink NR V2X communication systems. [0077] FIG. 2 illustrates a block diagram of a communication device in accordance with some embodiments. The communication device 200 may be a UE such as a specialized computer, a personal or laptop computer (PC), a tablet PC, or a smart phone, dedicated network equipment such as an eNB, a server running software to configure the server to operate as a network device, a virtual device, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. For example, the communication device 200 may be implemented as one or more of the devices shown in FIG. 1. Note that communications described herein may be encoded before transmission by the transmitting entity (e.g., UE, gNB) for reception by the receiving entity (e.g., gNB, UE) and decoded after reception by the receiving entity. [0078] Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules and components are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instructions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a machine readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations. [0079] Accordingly, the term “module” (and “component”) is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using software, the general-purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time. [0080] The communication device 200 may include a hardware processor (or equivalently processing circuitry) 202 (e.g., a central processing unit (CPU), a GPU, a hardware processor core, or any combination thereof), a main memory 204 and a static memory 206, some or all of which may communicate with each other via an interlink (e.g., bus) 208. The main memory 204 may contain any or all of removable storage and non-removable storage, volatile memory or non-volatile memory. The communication device 200 may further include a display unit 210 such as a video display, an alphanumeric input device 212 (e.g., a keyboard), and a user interface (UI) navigation device 214 (e.g., a mouse). In an example, the display unit 210, input device 212 and UI navigation device 214 may be a touch screen display. The communication device 200 may additionally include a storage device (e.g., drive unit) 216, a signal generation device 218 (e.g., a speaker), a network interface device 220, and one or more sensors, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The communication device 200 may further include an output controller, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.). [0081] The storage device 216 may include a non-transitory machine readable medium 222 (hereinafter simply referred to as machine readable medium) on which is stored one or more sets of data structures or instructions 224 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 224 may also reside, completely or at least partially, within the main memory 204, within static memory 206, and/or within the hardware processor 202 during execution thereof by the communication device 200. While the machine readable medium 222 is illustrated as a single medium, the term "machine readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 224. [0082] The term “machine readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by the communication device 200 and that cause the communication device 200 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of machine readable media may include: non-volatile memory, such as semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Radio access Memory (RAM); and CD-ROM and DVD-ROM disks. [0083] The instructions 224 may further be transmitted or received over a communications network using a transmission medium 226 via the network interface device 220 utilizing any one of a number of wireless local area network (WLAN) transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks. Communications over the networks may include one or more different protocols, such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi, IEEE 802.16 family of standards known as WiMax, IEEE 802.15.4 family of standards, a Long Term Evolution (LTE) family of standards, a Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, a next generation (NG)/5^th generation (5G) standards among others. In an example, the network interface device 220 may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the transmission medium 226. [0084] Note that the term “circuitry” as used herein refers to, is part of, or includes hardware components such as an electronic circuit, a logic circuit, a processor (shared, dedicated, or group) and/or memory (shared, dedicated, or group), an Application Specific Integrated Circuit (ASIC), a field-programmable device (FPD) (e.g., a field-programmable gate array (FPGA), a programmable logic device (PLD), a complex PLD (CPLD), a high-capacity PLD (HCPLD), a structured ASIC, or a programmable SoC), digital signal processors (DSPs), etc., that are configured to provide the described functionality. In some embodiments, the circuitry may execute one or more software or firmware programs to provide at least some of the described functionality. The term “circuitry” may also refer to a combination of one or more hardware elements (or a combination of circuits used in an electrical or electronic system) with the program code used to carry out the functionality of that program code. In these embodiments, the combination of hardware elements and program code may be referred to as a particular type of circuitry. [0085] The term “processor circuitry” or “processor” as used herein thus refers to, is part of, or includes circuitry capable of sequentially and automatically carrying out a sequence of arithmetic or logical operations, or recording, storing, and/or transferring digital data. The term “processor circuitry” or “processor” may refer to one or more application processors, one or more baseband processors, a physical central processing unit (CPU), a single- or multi-core processor, and/or any other device capable of executing or otherwise operating computer-executable instructions, such as program code, software modules, and/or functional processes. [0086] Any of the radio links described herein may operate according to any one or more of the following radio communication technologies and/or standards including but not limited to: a Global System for Mobile Communications (GSM) radio communication technology, a General Packet Radio Service (GPRS) radio communication technology, an Enhanced Data Rates for GSM Evolution (EDGE) radio communication technology, and/or a Third Generation Partnership Project (3GPP) radio communication technology, for example Universal Mobile Telecommunications System (UMTS), Freedom of Multimedia Access (FOMA), 3GPP Long Term Evolution (LTE), 3GPP Long Term Evolution Advanced (LTE Advanced), Code division multiple access 2000 (CDMA2000), Cellular Digital Packet Data (CDPD), Mobitex, Third Generation (3G), Circuit Switched Data (CSD), High-Speed Circuit-Switched Data (HSCSD), Universal Mobile Telecommunications System (Third Generation) (UMTS (3G)), Wideband Code Division Multiple Access (Universal Mobile Telecommunications System) (W-CDMA (UMTS)), High Speed Packet Access (HSPA), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+), Universal Mobile Telecommunications System-Time-Division Duplex (UMTS-TDD), Time Division-Code Division Multiple Access (TD-CDMA), Time Division- Synchronous Code Division Multiple Access (TD-CDMA), 3rd Generation Partnership Project Release 8 (Pre-4th Generation) (3GPP Rel. 8 (Pre-4G)), 3GPP Rel. 9 (3rd Generation Partnership Project Release 9), 3GPP Rel. 10 (3rd Generation Partnership Project Release 10) , 3GPP Rel. 11 (3rd Generation Partnership Project Release 11), 3GPP Rel. 12 (3rd Generation Partnership Project Release 12), 3GPP Rel. 13 (3rd Generation Partnership Project Release 13), 3GPP Rel. 14 (3rd Generation Partnership Project Release 14), 3GPP Rel. 15 (3rd Generation Partnership Project Release 15), 3GPP Rel. 16 (3rd Generation Partnership Project Release 16), 3GPP Rel. 17 (3rd Generation Partnership Project Release 17) and subsequent Releases (such as Rel. 18, Rel. 19, etc.), 3GPP 5G, 5G, 5G New Radio (5G NR), 3GPP 5G New Radio, 3GPP LTE Extra, LTE-Advanced Pro, LTE Licensed-Assisted Access (LAA), MuLTEfire, UMTS Terrestrial Radio Access (UTRA), Evolved UMTS Terrestrial Radio Access (E-UTRA), Long Term Evolution Advanced (4th Generation) (LTE Advanced (4G)), cdmaOne (2G), Code division multiple access 2000 (Third generation) (CDMA2000 (3G)), Evolution-Data Optimized or Evolution-Data Only (EV-DO), Advanced Mobile Phone System (1st Generation) (AMPS (1G)), Total Access Communication System/Extended Total Access Communication System (TACS/ETACS), Digital AMPS (2nd Generation) (D-AMPS (2G)), Push-to-talk (PTT), Mobile Telephone System (MTS), Improved Mobile Telephone System (IMTS), Advanced Mobile Telephone System (AMTS), OLT (Norwegian for Offentlig Landmobil Telefoni, Public Land Mobile Telephony), MTD (Swedish abbreviation for Mobiltelefonisystem D, or Mobile telephony system D), Public Automated Land Mobile (Autotel/PALM), ARP (Finnish for Autoradiopuhelin, "car radio phone"), NMT (Nordic Mobile Telephony), High capacity version of NTT (Nippon Telegraph and Telephone) (Hicap), Cellular Digital Packet Data (CDPD), Mobitex, DataTAC, Integrated Digital Enhanced Network (iDEN), Personal Digital Cellular (PDC), Circuit Switched Data (CSD), Personal Handy- phone System (PHS), Wideband Integrated Digital Enhanced Network (WiDEN), iBurst, Unlicensed Mobile Access (UMA), also referred to as also referred to as 3GPP Generic Access Network, or GAN standard), Zigbee, Bluetooth(r), Wireless Gigabit Alliance (WiGig) standard, mmWave standards in general (wireless systems operating at 10-300 GHz and above such as WiGig, IEEE 802.11ad, IEEE 802.11ay, etc.), technologies operating above 300 GHz and THz bands, (3GPP/LTE based or IEEE 802.11p or IEEE 802.11bd and other) Vehicle-to-Vehicle (V2V) and Vehicle-to-X (V2X) and Vehicle-to- Infrastructure (V2I) and Infrastructure-to-Vehicle (I2V) communication technologies, 3GPP cellular V2X, DSRC (Dedicated Short Range Communications) communication systems such as Intelligent-Transport-Systems and others (typically operating in 5850 MHz to 5925 MHz or above (typically up to 5935 MHz following change proposals in CEPT Report 71)), the European ITS-G5 system (i.e. the European flavor of IEEE 802.11p based DSRC, including ITS-G5A (i.e., Operation of ITS-G5 in European ITS frequency bands dedicated to ITS for safety re-lated applications in the frequency range 5,875 GHz to 5,905 GHz), ITS-G5B (i.e., Operation in European ITS frequency bands dedicated to ITS non- safety applications in the frequency range 5,855 GHz to 5,875 GHz), ITS-G5C (i.e., Operation of ITS applications in the frequency range 5,470 GHz to 5,725 GHz)), DSRC in Japan in the 700MHz band (including 715 MHz to 725 MHz), IEEE 802.11bd based systems, etc. [0087] Aspects described herein can be used in the context of any spectrum management scheme including dedicated licensed spectrum, unlicensed spectrum, license exempt spectrum, (licensed) shared spectrum (such as LSA = Licensed Shared Access in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz and further frequencies and SAS = Spectrum Access System / CBRS = Citizen Broadband Radio System in 3.55-3.7 GHz and further frequencies). Applicable spectrum bands include IMT (International Mobile Telecommunications) spectrum as well as other types of spectrum/bands, such as bands with national allocation (including 450 - 470 MHz, 902-928 MHz (note: allocated for example in US (FCC Part 15)), 863-868.6 MHz (note: allocated for example in European Union (ETSI EN 300220)), 915.9-929.7 MHz (note: allocated for example in Japan), 917-923.5 MHz (note: allocated for example in South Korea), 755-779 MHz and 779-787 MHz (note: allocated for example in China), 790 - 960 MHz, 1710 - 2025 MHz, 2110 - 2200 MHz, 2300 - 2400 MHz, 2.4-2.4835 GHz (note: it is an ISM band with global availability and it is used by Wi-Fi technology family (11b/g/n/ax) and also by Bluetooth), 2500 - 2690 MHz, 698-790 MHz, 610 - 790 MHz, 3400 - 3600 MHz, 3400 – 3800 MHz, 3800 – 4200 MHz, 3.55- 3.7 GHz (note: allocated for example in the US for Citizen Broadband Radio Service), 5.15-5.25 GHz and 5.25-5.35 GHz and 5.47-5.725 GHz and 5.725-5.85 GHz bands (note: allocated for example in the US (FCC part 15), consists four U-NII bands in total 500 MHz spectrum), 5.725-5.875 GHz (note: allocated for example in EU (ETSI EN 301893)), 5.47-5.65 GHz (note: allocated for example in South Korea, 5925-7125 MHz and 5925-6425MHz band (note: under consideration in US and EU, respectively. Next generation Wi-Fi system is expected to include the 6 GHz spectrum as operating band but it is noted that, as of December 2017, Wi-Fi system is not yet allowed in this band. Regulation is expected to be finished in 2019-2020 time frame), IMT-advanced spectrum, IMT-2020 spectrum (expected to include 3600-3800 MHz, 3800 – 4200 MHz, 3.5 GHz bands, 700 MHz bands, bands within the 24.25-86 GHz range, etc.), spectrum made available under FCC's "Spectrum Frontier" 5G initiative (including 27.5 - 28.35 GHz, 29.1 - 29.25 GHz, 31 - 31.3 GHz, 37 - 38.6 GHz, 38.6 - 40 GHz, 42 - 42.5 GHz, 57 - 64 GHz, 71 - 76 GHz, 81 - 86 GHz and 92 - 94 GHz, etc), the ITS (Intelligent Transport Systems) band of 5.9 GHz (typically 5.85-5.925 GHz) and 63-64 GHz, bands currently allocated to WiGig such as WiGig Band 1 (57.24-59.40 GHz), WiGig Band 2 (59.40-61.56 GHz) and WiGig Band 3 (61.56-63.72 GHz) and WiGig Band 4 (63.72-65.88 GHz), 57- 64/66 GHz (note: this band has near-global designation for Multi-Gigabit Wireless Systems (MGWS)/WiGig . In US (FCC part 15) allocates total 14 GHz spectrum, while EU (ETSI EN 302567 and ETSI EN 301217-2 for fixed P2P) allocates total 9 GHz spectrum), the 70.2 GHz - 71 GHz band, any band between 65.88 GHz and 71 GHz, bands currently allocated to automotive radar applications such as 76-81 GHz, and future bands including 94-300 GHz and above. Furthermore, the scheme can be used on a secondary basis on bands such as the TV White Space bands (typically below 790 MHz) where in particular the 400 MHz and 700 MHz bands are promising candidates. Besides cellular applications, specific applications for vertical markets may be addressed such as PMSE (Program Making and Special Events), medical, health, surgery, automotive, low-latency, drones, etc. applications. [0088] 3GPP Rel-16 specified various location technologies to support regulatory as well as commercial use cases. The target horizontal positioning requirements for commercial use cases studied in Rel-16 were <3 m (80%) for indoor scenarios and <10 m (80%) for outdoor scenarios. The 5G service requirements include High Accuracy Positioning, which are characterized by ambitious system requirements for positioning accuracy in many verticals. For example, on a factory floor, it is desirable to locate assets and moving objects such as forklifts, or parts to be assembled. Other areas, such as transportation and logistics for example, have similar desires. [0089] Emerging applications relying on high-precision positioning technology in autonomous applications (e.g., automotive), has brought with it the desire for high integrity and reliability in addition to high accuracy. Integrity is the measure of trust that can be placed in the correctness of information supplied by a navigation system. Integrity includes the ability of a system to provide timely warnings to user receivers in case of failure. The 5G service requirements include the determining the reliability, and the uncertainty or confidence level, of the position-related data. [0090] The NR positioning enhancements in 3GPP Rel-17 are being developed to address higher accuracy location and lower latency requirements resulting from new applications and use cases. The positioning enhancements should be evaluated and specified to meet the agreed upon requirements. As described, for the general commercial use cases, a sub-meter level accuracy (< 1 m) should be achieved with a target latency of less than hundred milliseconds (< 100 ms). For the industrial internet of things (IIoT) use cases, the requirements are stricter, and the positioning accuracy should be less than 0.2 m with the required latency of less than 10 ms. [0091] In particular, 3GPP NR Positioning in Rel-17 should evaluate and specify enhancements and solutions to meet the following exemplary performance targets: (a) For general commercial use cases: sub-meter level position accuracy (< 1 m); (b) For IIoT Use Cases: position accuracy < 0.2 m. The target latency requirement is < 100 ms; for some IIoT use cases, latency in the order of 10 ms is desired. For the evaluation of solutions, the Rel-16 scenarios and channel models may be reused where applicable, and additional scenarios for IIoT use cases should be defined. [0092] Therefore, identification and evaluation of the positioning techniques, including DL and UL reference signals, signaling, and procedures for improved accuracy, reduced latency, network and device efficiency is desired. However, there are currently no known low latency and high accuracy positioning solutions. [0093] The embodiments herein provide a two-step and a four-step PRACH procedure similar to existing PRACH procedures defined in 3GPP TS 38.211 v16.2.0 but applied for positioning services. These embodiments provide substantial latency reduction in comparison to existing positioning services/solutions, and in particular, for UEs in the RRC_IDLE or RRC_INACTIVE state. A UE in the RRC_IDLE or RRC_INACTIVE state may get channel access applying a two-step PRACH procedure defined in the above standard. The UE sends the PRACH preamble accompanied by the msgA message to a serving access node (AN) (such as a gNB) with a channel access response. If successful, a serving AN responds with a msgB message that includes a contention resolution and/or random access response. [0094] In some embodiments, the existing two-step PRACH procedure is generalized and positioning reference signals are introduced, including Sounding Reference Signals (SRS) and Positioning Reference Signals (PRS) for UL/DL transmission. This allows UEs to perform positioning measurements at an earlier stage during the random-access procedure, which in turn reduces the overall latency. Usage of the SRS/PRS signals for the timing measurements instead of the PRACH preamble signal results in the improved accuracy for the distance estimation. [0095] A UE performing a two-step or a four-step PRACH procedure for positioning may exchange the reference signals and the payload messages not only with a serving gNB, but also with the multiple neighbor gNBs. The simultaneous operation with the multiple number of gNBs allows for substantial latency reduction. [0096] The two-step and a four-step PRACH positioning procedure embodiments discussed herein provide substantial latency reduction, in particular, for UEs in the RRC_IDLE or RRC_INACTIVE state. The embodiments herein improve positioning latency and performance of NR communication systems, and also improve energy efficiency for positioning operation of NR communication systems. [0097] PRACH POSITIONING ASPECTS [0098] In Rel-15 NR, a 4-step procedure used for initial contention based random access (also referred to as a “random access procedure” or “RACH procedure”) was defined. FIG. 3 illustrates a 4-step RACH procedure in accordance with some embodiments. As illustrated in FIG. 3, in the first step of the 4-step procedure, the UE transmits a PRACH in the uplink by selecting one preamble signature (e.g., Msg1: random access preamble in FIG. 3). This allows the gNB to estimate the delay between the gNB and the UE for subsequent UL timing adjustment. The random access preamble is selected/determined according to subclause 8.1 of 3GPP RP-193237 New SID NR Positioning enhancements. Subsequently, in the second step, the gNB feedbacks a random access response (RAR), which carries timing advanced (TA) command information and uplink grant for the uplink transmission. Next, in the third step, the UE transmits a layer 1/layer 2 (L1/L2) message (e.g., Msg3) over the PUSCH, which may carry contention resolution ID and/or other information. The Msg3 may be a message transmitted on the uplink shared channel (UL- SCH) containing a Cell Radio Network Temporary Identifier (C-RNTI) Medium Access Control (MAC) Control Element (CE) or Common Control Channel (CCCH) Service Data Unit (SDU), submitted from the upper layer and associated with the UE Contention Resolution Identity, as part of a Random Access procedure. In the fourth step, the gNB sends a contention resolution message (e.g., Msg4) in the physical downlink shared channel (PDSCH). [0099] Existing NR positioning approaches support three types of radio access technology (RAT) dependent positioning solutions including DL only based solutions (e.g., gNB transmits reference signal and UE performs measurement of signal location parameters (SLPs); downlink Time Difference of Arrival (DL-TDOA), DL Reference Signal Time Difference (RSTD) measurement, etc.), UL only based solutions (e.g., UEs transmit reference signal and gNBs perform measurement of SLPs; uplink Time Difference of Arrival (UL-TDOA) UL RSTD measurement, etc.), and DL & UL only based solutions (e.g., gNB and UE transmits reference signal and gNB and UE perform measurement of SLPs; RTT measurements, etc.). Combinations of DL only, UL only, DL & UL based solutions may be used. [00100] SLPs are parameters of signaling/messages that can be applied for the purpose of UE positioning such as phase difference, time of arrival, time of arrival timestamps, time difference of arrival, propagation time/delays, angle of arrivals/departures, reference signal received power (RSRP), reference signal received quality (RSRQ), and/or any other information that can be relevant to facilitate an estimate of UE geographical coordinates. [00101] PRS are the signals sent by ANs (e.g., cells, eNBs, gNBs, transmission reception points (TRPs), Network Entities, etc.) and/or UEs used to measure SLPs, which knowledge is beneficial for UE location. PRS can include specifically designed sequences and signals with good cross and autocorrelation properties, or any data transmission depending on implementation and measurement and reporting type. Examples of such signals in UL include PRACH, SRS or PRS/ranging signals. Examples of such signals in DL include PRS, Channel State Information Reference Signal (CSI-RS), Cell Specific Reference Signal (CRS), and the like. [00102] Reference resources (or PRS resource) refer to resources where PRS is transmitted characterized by stamp/ID, timestamp, etc., that can be configured by higher layer signaling and may be configured to UE for measurement and reporting. For instance, the following ID may be used: PRS resource ID, CSI-RS resource ID, UL SRS Resource ID, PRACH resource ID, etc. [00103] In Rel-16 NR, a 2-step RACH procedure was defined, with the motivation to allow fast access and low latency uplink transmission. FIG. 4 illustrates a 2-step RACH procedure in accordance with some embodiments. In particular, the 4-step RACH procedure is reduced to 2 steps, where a UE may combine Msg1 and Msg3 in the conventional RACH procedure for low latency PRACH transmission. For example, in the first step of the 2-step RACH procedure, the UE transmits a PRACH preamble and associated MsgA PUSCH on a configured time and frequency resource, where the MsgA PUSCH may carry at least equivalent contents of Msg3 in the 4-step RACH procedure. In the second step of the 2-step RACH procedure, after the gNB YX16 successful detects the PRACH preamble and decodes the MsgA PUSCH, the gNB YX16 transmits an MsgB that may carry equivalent contents of Msg2 and Msg4 in 4- step RACH procedure. [00104] A 2-step RACH approach can be used for positioning services, which is characterized by MsgA transmission from a UE to a gNB and MsgB transmission from a gNB to a UE. In case of UE-initiated positioning, the MsgA can be considered as a positioning request while the MsgB as a positioning response. The transmission timing relationship between these two messages (e.g., transmission MsgA and reception MsgB) can be predefined, indicated in MsgA or determined by gNB. [00105] As illustrated in FIG. 4, a 2-step Positioning RACH procedure includes the UE transmitting the PRACH preamble and a Positioning Request within Msg1, and the gNB detects PRACH preamble and Msg1 and sends a Positioning Response by MsgB: incorporating Positioning response Msg2. [00106] The 2-step RACH approach can be used to trigger any type of NR positioning technique and solution (e.g., DL only (D-TDOA), UL only (U- TDOA), DL&UL E-CID and/or RTT). There may be multiple variations of different NR positioning procedures depending on the requested positioning approach. [00107] EXAMPLE EMBODIMENTS [00108] SYNCHRONIZATION AND CONFIGURATION EMBODIMENTS [00109] Embodiments include a two-step and four-step PRACH procedure for positioning. The positioning procedure is performed by a UE with a single serving gNB or with a serving gNBs and multiple neighbor gNBs. The UE performing PRACH for positioning may be in the RRC_IDLE or RRC_INACTIVE state. [00110] The UE may transmit the UL reference signal and the payload message to a single serving gNB or to a serving gNB and multiple neighbor gNBs. The UE may receive the DL reference signal and the payload message from the serving gNB or from the serving gNB and one or more neighbor gNBs. [00111] The serving gNB may transmit the payload message to a single neighbor gNB or multiple neighbor gNBs using a backhaul link. The serving gNB may receive the payload message from a single neighbor gNB or multiple neighbor gNBs using respective backhaul links. [00112] The UL reference signal may include a UL SRS, UL PRS, PRACH preamble, and/or any other type of the reference signal suitable for timing measurements. The DL reference signal may include a DL SRS, DL PRS, and/or any other type of the reference signal suitable for timing measurements as well as reference signals defined in the previous standard releases. [00113] The UL payload message may be transmitted using a PUSCH and/or a PUCCH. The DL payload message may be transmitted using a PDSCH) and/or a PDCCH. [00114] The UE performing the PRACH for positioning may acquire the initial time synchronization through reception of a single or multiple Synchronization Signal Blocks (SSBs) from a single or multiple gNBs. The UE demodulates the Physical Cell ID (PCI) of each received SSB and decodes the Master Information Block (MIB) to extract main cell parameters. [00115] The UE performs RSRP measurements, or some other suitable measurement(s), for each received SSB and creates the list of PCIs corresponding to the gNBs with the RSRPs exceeded the threshold. One of the gNBs is selected as a serving gNB and the other gNBs are selected as neighbor gNBs. [00116] The UE may acquire the PRACH positioning configuration through reception of a System Information Block (SIB) from the serving gNB or through reception of LTE Positioning Protocol (LPP) assistance data. The serving gNB provides a common PRACH configuration for positioning, including the following fields: [00117] The list of PCIs for the neighbor gNBs supporting common/shared configuration; [00118] A group ID of the gNBs supporting common configuration for positioning; [00119] Time-frequency occasions for the UL reference signal and UL payload message transmission. Time occasions are defined by: System Frame Number (SFN), n_SFN, Subframe index within the frame, nSF, Time slot index within the subframe, nslot, OFDM symbol indexes within the time slot, nOFDM; Frequency occasions are defined by: Frequency offset from the start of the initial or active Bandwidth Part (BWP), koffset, The number of Physical Resource Blocks (PRBs) defined per frequency occasion, NPRB, The size of the guard band between the successive frequency occasions, kGB, The total number of frequency occasions, kFO; [00120] PRACH preamble group indexes allocated for positioning: Total number of PRACH preambles allocated for positioning, Root sequence index, Cyclic shift of the sequence; [00121] SSB indexes for each of the PCIs; and [00122] Mapping between the SSB indexes and the time-frequency occasions for each of the PCIs. [00123] The frequency occasions can be specific for a UE, and therefore, the frequency occasions for the UE may be shared across the group of gNBs participating in the positioning procedure. [00124] FIG. 5 illustrates a time-frequency occasions configuration and system frame indexes counting for 5^th generation NodeBs (gNBs) in accordance with some embodiments. The time-frequency occasions configuration and the SFNs counting is shown for two gNBs, numbered as gNB1 and gNB2. One of the gNBs could be a serving gNB and another one could be a neighbor gNB. [00125] In the example, an SFN includes 10 subframes, each subframe includes two time slots, and each time slot includes 14 OFDM symbols. The time occasion may correspond to a single OFDM symbol or a group of successive OFDM symbols. [00126] The frequency domain occasion may correspond to the NPRB Physical Resource Blocks (PRBs), separated by the kGB PRBs as a guard band, and taken with an offset of koffset from the start of the initial or active Bandwidth Part (BWP). The total number of frequency occasions is specified by the kFO parameter. [00127] The serving gNB and multiple neighbor gNBs may be synchronized (e.g., their subframe boundaries may be aligned in time). The serving gNB and each of the multiple neighbor gNBs may have independent SFN counting. The UE may use the SFN counter and parameters provided by a serving gNB. [00128] FIG. 5 illustrates a time-frequency occasions configuration and system frame indexes counting for gNBs in accordance with some embodiments. In this case, gNB1 and the gNB2 are synchronized in time, i.e. their subframe boundaries are aligned in time. However, the gNB1 has n_SFN = i and the gNB2 has n_SFN = k, where i≠k. FIG. 6 illustrates a synchronization procedure between a UE and the gNBs in accordance with some embodiments. One of the gNBs could be a serving gNB and another one could be a neighbor gNB. [00129] In the considered example, a UE has a shorter distance to the gNB1 and a longer distance to the gNB2, with the propagation times T_p1 and T_p2, respectively, where T_p1 < T_p2. A UE receives the SSB from the gNB1, denoted as SSB1 earlier compared to the SSB from the gNB2 denoted as SSB2. The relative time difference between the synchronization acquired using SSB1 and SSB2 is equal to ΔT = T_p2 – T_p1. [00130] A UE may perform synchronization using the SSB1, i.e. the earliest received SSB, and transmit UL reference signal and UL payload message using zero timing advance T_TA1 = 0 to the gNB1 and with the value that may be viewed as a non-zero timing advance T_TA2 = ΔT to the gNB2. The gNB1 may receive the signal with the RTT delay equal to 2× T_p1. The gNB2 may receive the signal with the time delay T_p1 + T_p2, which is not an RTT time due to non-zero timing advance T_TA2. [00131] A UE may transmit the UL reference signal and the UL payload message with a Guard Period (GP) at the end of the signal to avoid Inter Symbol Interference (ISI) to the successive transmission. The duration of the GP should exceed the duration of the largest possible delay caused by the propagation time delay. [00132] A UE may transmit the UL reference signal and the UL payload message to a serving gNB and multiple neighbor gNBs concurrently at the same time-frequency occasion, using a synchronization procedure shown in FIG. 6. A UE may transmit the UL reference signal and the UL payload message to a serving gNB and multiple neighbor gNBs using different time-frequency occasions. [00133] Different UEs may use different PRACH preamble indexes during UL transmission. The UEs may use a dedicated set of the PRACH preambles allocated for positioning only with a specific group ID. [00134] A serving gNB and multiple neighbor gNBs may use a common/shared PRACH configuration for positioning which is differed from other configurations used by gNBs for initial random-access. In that case the time-frequency occasions allocated for the positioning are differed from the time-frequency occasions allocated for the initial random-access. It may be achieved by using different SFNs, different subframe indexes, different time slot indexes, different OFDM symbol indexes and/or different frequency occasions. [00135] A serving gNB and multiple neighbor gNBs may use a common/shared PRACH configuration with the time-frequency occasions overlapped with one or more time-frequency occasions of other configurations used by gNBs for initial random-access. In that case a serving gNB and multiple neighbor gNBs may use a dedicated set of the PRACH preambles with a specific group ID, which is differed from other sets of the preambles used for initial random-access. [00136] A serving gNB and multiple neighbor gNBs may use a common/shared PRACH configuration with the time-frequency occasions overlapped with one or more time-frequency occasions of other configurations used by gNBs for initial random-access and overlapped set of the PRACH preambles. In that case a UE should send a group ID as a part of the payload message to associate the time-frequency occasions and the used PRACH preambles to the positioning request. [00137] TWO-STEP PRACH FOR POSITIONING EMBODIMENTS [00138] The UE may use a two-step or a four-step PRACH procedure for positioning. FIG. 7 illustrates a 2-step RACH procedure for positioning in accordance with some embodiments. [00139] FIRST STEP [00140] The first step (or step A) of a two-step PRACH procedure for positioning should include an UL transmission of SigA from a UE to a serving gNB, may include an UL transmission of SigA1i from a UE to the i-th neighbor gNB, and may include a backhaul transmission of SigA2i from a serving gNB to the i-th neighbor gNB. [00141] As a part of the UL transmission, a UE should send SigA to a serving gNB, where SigA may be one of the following: SigA = PRACH preamble, SigA = PRACH preamble + msgA, SigA = PRACH preamble + UL SRS (or UL PRS), SigA = PRACH preamble + msgA + UL SRS (or UL PRS), SigA = UL SRS (or UL PRS), SigA = UL SRS (or UL PRS) + msgA. [00142] As a part of the UL transmission, a UE may send SigA1i to the i- th neighbor gNB, where SigA1i may be one of the following: SigA1i = SigA, SigA1i = PRACH preamble, SigA1i = PRACH preamble + msgAi, SigA1i = PRACH preamble + UL SRS (or UL PRS), SigA1i = PRACH preamble + msgAi + UL SRS (or UL PRS), SigA1i = UL SRS (or UL PRS), SigA1i = UL SRS (or UL PRS) + msgAi, SigA1i = N/A. The notation “SigA1i = N/A” denotes the case when the SigA1i is not transmitted from a UE to the i-th neighbor gNB. [00143] As a part of the backhaul transmission, a serving gNB may send SigA2i to the i-th neighbor gNB, where SigA2i may be one of the following: SigA2i = msgAi, SigA2i = N/A. [00144] The notation “SigA2i = N/A” denotes the case when the SigA2i is not transmitted from a serving gNB to the i-th neighbor gNB. [00145] The msgA and msgAi in the above are the payload messages. [00146] SECOND STEP [00147] The second step (or step B) of a two-step PRACH procedure for positioning should include a DL transmission of SigB from a serving gNB to a UE, may include a DL transmission of SigB1i from the i-th neighbor gNB to a UE, and may include a backhaul transmission of SigB2i from the i-th neighbor gNB to a serving gNB. [00148] As a part of the DL transmission, a serving gNB should send SigB to a UE, where SigB may be one of the following: SigB = msgB, SigB = msgB + DL PRS, SigB = DL PRS. [00149] As a part of the DL transmission, the i-th neighbor gNB may send SigB1i to a UE, where SigB1i may be one of the following: SigB1i = msgBi, SigB1i = msgBi + DL PRS, SigB1i = DL PRS, SigB1i = N/A. The notation “SigB1i = N/A” denotes the case when the SigB1i is not transmitted from the i- th neighbor gNB to a UE. [00150] As a part of the backhaul transmission, the i-th neighbor gNB may send SigB2i to a serving gNB, where SigB2i may be one of the following: SigB2i = msgBi, SigB2i = N/A. The notation “SigB2i = N/A” denotes the case when the SigB2i is not transmitted from the i-th neighbor gNB to a serving gNB. [00151] The msgB and msgBi in the above are the payload messages. [00152] Any combination of the signal transmissions SigA, SigA1i, SigA2i, SigB, SigB1i, and SigB2i from the lists provided above is possible. [00153] FOUR-STEP PRACH FOR POSITIONING [00154] FIG. 8 illustrates a 4-step RACH procedure for positioning in accordance with some embodiments. [00155] FIRST STEP [00156] The first step (or step A) of a four-step PRACH procedure for positioning should include an UL transmission of SigA from a UE to a serving gNB, may include an UL transmission of SigA1i from a UE to the i-th neighbor gNB, and may include a backhaul transmission of SigA2i from a serving gNB to the i-th neighbor gNB. [00157] As a part of the UL transmission, a UE should send SigA to a serving gNB, where SigA may be one of the following: SigA = PRACH preamble, SigA = PRACH preamble + msgA. [00158] As a part of the UL transmission, a UE may send SigA1i to the i- th neighbor gNB, where SigA1i may be one of the following: SigA1i = SigA, SigA1i = PRACH preamble, SigA1i = PRACH preamble + msgAi, SigA1i = N/A. The notation “SigA1i = N/A” denotes the case when the SigA1i is not transmitted from a UE to the i-th neighbor gNB. [00159] As a part of the backhaul transmission, a serving gNB may send SigA2i to the i-th neighbor gNB, where SigA2i may be one of the following: SigA2i = msgAi, SigA2i = N/A. The notation “SigA2i = N/A” denotes the case when the SigA2i is not transmitted from a serving gNB to the i-th neighbor gNB. [00160] The msgA and msgAi in the above are the payload messages. [00161] Second Step [00162] The second step (or step B) of a four-step PRACH procedure for positioning should include a DL transmission of SigB from a serving gNB to a UE, may include a DL transmission of SigB1i from the i-th neighbor gNB to a UE, and may include a backhaul transmission of SigB2i from the i-th neighbor gNB to a serving gNB. [00163] As a part of the DL transmission, a serving gNB should send SigB to a UE, where SigB may be one of the following: SigB = msgB. [00164] As a part of the DL transmission, the i-th neighbor gNB may send SigB1i to a UE, where SigB1i may be one of the following: SigB1i = msgBi, SigB1i = N/A. The notation “SigB1i = N/A” denotes the case when the SigB1i is not transmitted from the i-th neighbor gNB to a UE. [00165] As a part of the backhaul transmission, the i-th neighbor gNB may send SigB2i to a serving gNB, where SigB2i may be one of the following: SigB2i = msgBi, SigB2i = N/A. The notation “SigB2i = N/A” denotes the case when the SigB2i is not transmitted from the i-th neighbor gNB to a serving gNB. [00166] The msgB and msgBi in the above are the payload messages. [00167] Third Step [00168] The third step (or step C) of a four-step PRACH procedure for positioning should include an UL transmission of SigC from a UE to a serving gNB, may include an UL transmission of SigC1i from a UE to the i-th neighbor gNB, and may include a backhaul transmission of SigC2i from a serving gNB to the i-th neighbor gNB. [00169] As a part of the UL transmission, a UE should send SigC to a serving gNB, where SigC may be one of the following: SigC = UL SRS (or UL PRS), SigC = UL SRS (or UL PRS) + msgC, SigC = msgC, SigC = N/A. The notation “SigC = N/A” denotes the case when the SigC is not transmitted from the i-th neighbor gNB to a serving gNB. [00170] As a part of the UL transmission, a UE may send SigC1i to the i- th neighbor gNB, where SigC1i may be one of the following: SigC1i = SigC, SigC1i = UL SRS (or UL PRS), SigC1i = UL SRS (or UL PRS) + msgCi, SigC1i = msgCi, SigC1i = N/A. The notation “SigC1i = N/A” denotes the case when the SigC1i is not transmitted from a UE to the i-th neighbor gNB. [00171] As a part of the backhaul transmission, a serving gNB may send SigC2i to the i-th neighbor gNB, where SigC2i may be one of the following: SigC2i = msgCi, SigC2i = N/A. The notation “SigC2i = N/A” denotes the case when the SigC2i is not transmitted from a serving gNB to the i-th neighbor gNB. [00172] The msgC and msgCi in the above are the payload messages. [00173] Fourth Step [00174] The fourth step (or step D) of a four-step PRACH procedure for positioning should include a DL transmission of SigD from a serving gNB to a UE, may include a DL transmission of SigD1i from the i-th neighbor gNB to a UE, and may include a backhaul transmission of SigD2i from the i-th neighbor gNB to a serving gNB. [00175] As a part of the DL transmission, a serving gNB should send SigD to a UE, where SigD may be one of the following: SigD = DL PRS, SigD = DL PRS + msgD, SigD = msgD. [00176] As a part of the DL transmission, the i-th neighbor gNB may send SigD1i to a UE, where SigD1i may be one of the following: SigD1i = DL PRS, SigD1i = DL PRS + msgDi, SigD1i = msgDi, SigD1i = N/A. The notation “SigD1i = N/A” denotes the case when the SigD1i is not transmitted from the i- th neighbor gNB to a UE. [00177] As a part of the backhaul transmission, the i-th neighbor gNB may send SigD2i to a serving gNB, where SigD2i may be one of the following: SigD2i = msgDi, SigD2i = N/A. The notation “SigD2i = N/A” denotes the case when the SigD2i is not transmitted from the i-th neighbor gNB to a serving gNB. [00178] The msgD and msgDi in the above are the payload messages. [00179] Any combination of the signal transmissions SigA, SigA1i, SigA2i, SigB, SigB1i, SigB2i, SigC, SigC1i, SigC2i, SigD, SigD1i, and SigD2i from the lists provided above is possible. [00180] TWO-STEP PRACH FOR POSITIONING – PRIORITY 1 OPTION [00181] The first step (or step A) of a two-step PRACH procedure for priority 1 option should include an UL transmission of the PRACH preamble, msgA, and UL SRS from a UE to a serving gNB, should include an UL transmission of PRACH preamble, msgA, and UL SRS from a UE to the i-th neighbor gNB, and may include a backhaul transmission of msgA from a serving gNB to the i-th neighbor gNB. [00182] The second step (or step B) of a two-step PRACH procedure for positioning should include a DL transmission of the msgB and DL PRS from a serving gNB to a UE, should include a DL transmission of the Dl PRS from the i-th neighbor gNB to a UE, and may include a backhaul transmission of the msgB from the i-th neighbor gNB to a serving gNB. [00183] FIG. 9 illustrates another 2-step RACH procedure for positioning in accordance with some embodiments. The procedure of FIG. 9 is for a priority 1 option. [00184] A serving gNB may retransmit the msgA payload message to the single or multiple neighbor gNBs using a backhaul link, if a transmission by a UE of the msgA was not successful. This may happen due to link budget difference between the PRACH preamble and msgA transmissions. [00185] The i-th neighbor gNB may transmit the msgB payload message to a serving gNB using a backhaul link. [00186] Depending on the TypeOfMeasurement parameter, the following message exchange is possible: [00187] If TypeOfMeasurement = “RTT”, then: A UE transmits the PRACH preamble to a serving gNB and a single or multiple neighbor gNBs; A UE transmits the msgA to a serving gNB and a single or multiple neighbor gNBs, the msgA is transmitted with a certain offset in the time slot units relative to the given PRACH time slot; A UE transmits the UL SRS reference signal to a serving gNB and a single or multiple neighbor gNBs, the UL SRS is transmitted with a certain offset in time slot units relative to the given PRACH time slot; A serving gNB may retransmit the msgA to a single or multiple neighbor gNBs using a backhaul link; A single or multiple neighbor gNBs may transmit the msgB to a serving gNB using a backhaul link; A serving gNB transmits the msgB to a UE using a PDCCH/PDSCH channel; A serving gNB and a single or multiple neighbor gNBs transmit the DL PRS to a UE, the DL PRS is transmitted with a certain offset in time slot units relative to the given slot of msgB (transmitted by a serving gNB to a UE). [00188] If TypeOfMeasurement = “UL-TDOA”, then: A UE transmits the PRACH preamble to a serving gNB and a single or multiple neighbor gNBs; A UE transmits the msgA to a serving gNB and a single or multiple neighbor gNBs, the msgA is transmitted with a certain offset in the time slot units relative to the given PRACH time slot; A UE transmits the UL SRS reference signal to a serving gNB and a single or multiple neighbor gNBs, the UL SRS is transmitted with a certain offset in time slot units relative to the given PRACH time slot; A serving gNB may retransmit the msgA to a single or multiple neighbor gNBs using a backhaul link. [00189] If TypeOfMeasurement = “DL-TDOA”, then: A UE transmits the PRACH preamble to a serving gNB and a single or multiple neighbor gNBs; A UE transmits the msgA to a serving gNB and a single or multiple neighbor gNBs, the msgA is transmitted with a certain offset in the time slot units relative to the given PRACH time slot; A serving gNB may retransmit the msgA to a single or multiple neighbor gNBs using a backhaul link; A serving gNB transmits the msgB to a UE using a PDCCH/PDSCH channel; A serving gNB and a single or multiple neighbor gNBs transmit the DL PRS to a UE, the DL PRS is transmitted with a certain offset in time slot units relative to the given slot of msgB (transmitted by a serving gNB to a UE). [00190] A UE should acquire the UL SRS positioning configuration through reception of a SIB from a serving gNB or through reception of LTE Positioning Protocol (LPP) assistance data. A serving gNB provides a common/shared UL SRS configuration for positioning, including the following fields: UL-SRS-TimeDomainOffset – is the time domain offset in time slots relative to the PRACH slot; nrofSlotsUL-SRS – is the number of successive time slots occupied by the UL SRS; l₀ – is the starting position in the time domain, l₀ = N_symb ^slot – 1 – l_offset, l_offset = (0, 1, …, 13), N_symb ^slot = 14; N_symb ^SRS – is the total number of consecutive OFDM symbols, (1, 2, 4, 8, 12); k₀ – is the frequency- domain starting position of the UL SRS; K_TC – is the comb size of SRS transmission, (2, 4, 8); mSRS – is the total bandwidth that can be allocated for the UL SRS transmission in resource block units; n_ID ^SRS – sequence ID of the SRS transmission; groupOrSequenceHopping – is the parameter identifying group or sequence hopping type of transmission, (“neither”, “groupHopping”, “sequenceHopping”). [00191] All parameters may be the standard, except for the UL-SRS- TimeDomainOffset and nrofSlotsUL-SRS. These parameters may be added on top of the existing configuration structure. [00192] FIG. 10 illustrates mapping between a PRACH time slot and UL SRS time slots in accordance with some embodiments. In FIG. 10, the UL-SRS- TimeDomainOffset = 1 and nrofSlotUL-SRS = 2. [00193] A UE may transmit the msgA to a serving gNB and a single or multiple neighbor gNBs. The resource allocation and the modulation method of the msgA is kept unchanged with respect to the method described in the standard. [00194] The following fields are added to the msgA bit content: List of PCIs: PCI #1 – Serving gNB, PCI #2 – neighbor gNB #1, … PCI #N – neighbor gNB #N; TypeOfMeasurement: RTT, UL-TDOA, DL-TDOA; DL-PRS- ResourceBandwidth – is the total bandwidth allocated for the DL-PRS transmission in resource block units (depends on the UE bandwidth requesting the DL PRS), this field is present if RTT or DL-TDOA type of measurement is requested by a UE. [00195] The list of the Physical Cell IDs (PCIs) includes the list of the intendent recipients of the msgA payload content. It may be a subset of the gNBs, including a serving gNB and the number of neighbor gNBs. [00196] The TypeOfMeasurement field can be RTT, UL-TDOA or DL- TDOA. A serving gNB and the number of neighbor gNBs identify the type of the transmission and the possible response based on that field. The relevant scenarios are described above. [00197] The DL-PRS-ResourceBandwidth field provides a total bandwidth allocated in resource block units for the DL PRS transmission. This parameter is requested by a UE. [00198] A UE should acquire the DL PRS positioning configuration through reception of a SIB from a serving gNB or through reception of LTE Positioning Protocol (LPP) assistance data. A serving gNB provides a common/shared DL PRS configuration for positioning, including the following fields: DL-PRS-TimeDomainOffset - is the time domain offset in time slots of DL PRS slot relative to the msgB slot; nrofSlotsDL-PRS – is the number of successive time slots occupied by the DL PRS; n_ID,seq ^PRS – is the PRS sequence ID, (0, 1, …, 4095); l_start ^PRS – is the first DL PRS OFDM symbol index within the slot, (0, 1, …, 13); L_PRS – is the total number of DL PRS OFDM symbols, (2, 4, 6, 12); DL-PRS-PointA – the reference point for k = 0; K_comb ^PRS – is the comb size of PRS transmission, (2, 4, 6, 12); k_offset ^PRS – is the resource element offset, (0, 1, …, K_comb ^PRS-1); DL-PRS-ResourceBandwidth – is the total bandwidth that can be allocated for the DL PRS transmission in resource block units, (24:4:272). [00199] All parameters are standard, except for the DL-PRS- TimeDomainOffset and nrofSlotsDL-PRS. These parameters are new and added on top of the existing configuration structure. FIG. 11 illustrates mapping between a msgB time slot and a DL PRS time slot in accordance with some embodiments. As shown, the DL-PRS-TimeDomainOffset = 1 and nrofSlotDL- PRS = 1. [00200] The following fields are added to the msgB bit content: DL-PRS- TimeDomainOffset - is the time domain offset in time slots of DL PRS slot relative to the msgB slot; nrofSlotsDL-PRS – is the number of successive time slots occupied by the DL PRS; l_start ^PRS – is the first DL PRS OFDM symbol index within the slot, (0, 1, …, 13); L_PRS – is the total number of DL PRS OFDM symbols, (2, 4, 6, 12); (t3-t2) – is a serving gNB transmit-receive time difference; (t3i-t2i) – is the i-th neighbor gNB transmit-receive time difference. [00201] The transmit-receive time difference provided as a part of the msgB bit content represent the timestamp measurements. FIG. 12 illustrates RTT estimations in accordance with some embodiments. In particular, FIG. 12 illustrates the relevant time variables for RTT estimations. [00202] The following time variables are used: t1 – is the transmission time of the UL SRS reference signal by a UE to a serving gNB and a single or multiple neighbor gNBs; t2 – is the reception time of the UL SRS reference signal by a serving gNB; t2i – is the reception time of the UL SRS reference signal by the i-th neighbor gNB; t3 – is the transmission time of the DL PRS reference signal by a serving gNB to a UE; t3i – is the transmission time of the DL PRS reference signal by the i-th neighbor gNB to a UE; t4 – is the reception time of the DL PRS reference signal by a UE from a serving gNB; t4i – is the reception time of the DL PRS reference signal by a UE from the i-th gNB. [00203] In the above, a new two-step and a four-step PRACH procedure is described but applied for positioning. It allows for substantial latency reduction, specifically if a UE is in the RRC_IDLE or RRC_INACTIVE state. A UE in the RRC_IDLE or RRC_INACTIVE state may get channel access applying a two- step PRACH procedure defined in the standard. The UE sends the PRACH preamble accompanied by the msgA message to a serving gNB with a channel access response. If successful, a serving gNB responds with the msgB message that includes the contention resolution and/or random-access response. SRS and PRS for UL/DL transmission were introduced in two-step PRACH procedure. Therefore, a UE can perform positioning measurements at the earlier stage during the random-access procedure, which in turn reduces the overall latency. Usage of the SRS/PRS signals for the timing measurements instead of the PRACH preamble signal, results in the improved accuracy for the distance estimation. Here, a physical signal structure for the UL SRS and DL PRS reference signals for PRACH NR positioning procedure are provided. [00204] FIG. 13 illustrates another 2-step RACH procedure in accordance with some embodiments. As described above, the first step (or step A) of the two-step PRACH procedure includes an UL transmission of a PRACH preamble and payload msgA using a PUSCH. The second step (or step B) of a two-step PRACH procedure includes a DL transmission of payload msgB using a PDSCH or a PDCCH. [00205] PRACH Preamble Transmission [00206] A UE may transmit a PRACH preamble to a serving gNB to perform the initial random-access procedure in the predefined set of the time- frequency RACH Occasions (ROs). The PRACH transmission occasion in time domain is defined by the index n_t ^RA. [00207] An OFDM symbol index l of RO in time domain is defined in accordance with the following equation:

[00208] where: [00209] l₀ – is the starting OFDM symbol index [00210] n_t ^RA – is the RO time index [00211] N_t ^RA,slot – is the total number of ROs within the time slot [00212] N_dur ^RA – is the duration of the RO [00213] n_slot ^RA – is the time slot index [00214] A time-domain configuration is defined by the msgA-PRACH- ConfigurationIndex and the other parameters are derived based on this index. [00215] Table 1 shows an example of PRACH configuration table by example of msgA-PRACH-ConfigurationIndex = 68.

Table 1 An example of PRACH configuration table [00216] First, Table 1 defines a condition for the SFN n_SFN, which is in the range of (0, 1023), where a PRACH occasion may happen. The condition is written in the form: n_SFN mod x = y [00217] An example provided in Table 1 allows for the indexes n_SFN = 1, 9, 17, …, 1017. The considered condition provides a set of the valid indexes and configures the period of PRACH occasions in terms of the frame units. [00218] Second, Table 1defines a subframe index n_s,_f, which is equal to 9 in the provided example. Third, Table 1defines a starting symbol index l₀ within the subframe boundaries, which is equal to 0 in the provided example. Fourth, Table 1defines the total number of PRACH slots per subframe occasion, which is equal to 2 in the provided example. Fifth, Table 1defines the total number of PRACH occasions within a PRACH time slot, which is equal to 6 in the provided example. Sixth, Table 1 defines the duration of each of the PRACH occasions and is equal to 2 in the provided example. [00219] FIG. 14 illustrates PRACH time-domain occasions in accordance with some embodiments. Specifically, FIG. 14 shows an example of the considered configuration and the corresponding time-domain PRACH occasions. [00220] The PRACH transmission occasion in frequency domain is defined by the index n_RA, n_RA = 0, 1, …, msgA-RO-FDM – 1. msgA-RO-FDM defines the total number of the frequency-domain occasions. Each PRACH occasion is composed of the N_RB ^RA PRBs. The PRACH occasions are mapped with the frequency shift msgA-RO-FrequencyStart relative to the start of the Bandwidth Part (BWP). The PRACH occasions are mapped successively within the BWP. [00221] FIG. 15 illustrates PRACH frequency-domain occasions in accordance with some embodiments. In particular, FIG. 15 shows an example of PRACH frequency-domain occasions for the given index l of the OFDM symbol. The PRACH occasion may not be fully occupied and the red area in FIG. 15 highlights the actual populated subcarriers. The rest of the subcarriers are kept as the guard bands. The parameter k- defines the guard band size. [00222] MsgA PUSCH Transmission [00223] A UE may transmit a msgA PUSCH message to a serving gNB to perform the initial random-access procedure. A PRACH preamble and msgA should be transmitted in the different time slots. The configuration structure msgA-PUSCH-Config is used to specify the PUSCH allocation for the msgA relative to the valid PRACH slot in time domain. [00224] FIG. 16 illustrates a msgA PUSCH transmission in accordance with some embodiments. In particular, FIG. 15 shows an example of the msgA PUSCH transmission relative to the PRACH slot. msgA-PUSCH- TimeDomainOffset defines the time domain offset in time slots relative to the PRACH slot. nrofSlotsMsgA-PUSH defines the number of successive time slots occupied by the msgA PUSCH transmission. In the provided example msgA- PUSCH-TimeDomainOffset = 2 and nrofSlotsMsgS-PUSCH = 2. [00225] The msgA PUSCH Occasions (POs) within the time slot are defined by the following three parameters: startSymbolAndLengthMsgA – is the Start and Length Indicator Value (SLIV), i.e. S and L values where S – is the starting symbol index relative to the start of the time slot and L – is the number of consecutive OFDM symbols counting from the symbol with index S; guardPeriodMsgA-PUSCH – is the number of OFDM symbols separating the consecutive PUSCH occasions; nrofMsgA-PO-PerSlot – is the total number of PUSCH occasions in each time slot. [00226] FIG. 17 illustrates a msgA PUSCH time slot configuration in accordance with some embodiments. As shown, S = 4, L = 2, guardPeriodMsgA-PUSCH = 1, and nrofMsgA-PO-PerSlot = 3. [00227] The msgA PUSCH transmission occasion in frequency domain is defined by the index n_f, n_f = 0, 1, …, nrofMsgA-PO-FDM – 1. nrofMsgA-PO- FDM defines the total number of the frequency-domain occasions. Each msgA PUSCH occasion is composed of the nrofPRBs-PerMsgA-PO PRBs. The msgA PUSCH occasions are mapped with the frequency shift frequencyStartMsgA- PUSCH relative to the start of the BWP. The msgA PUSCH occasions are mapped successively with the BWP separated by the guard bands. guardBandMsgA-PUSCH defines the number of PRBs per guard band. [00228] FIG. 18 illustrates msgA PUSCH frequency-domain occasions in accordance with some embodiments. As shown in FIG. 18, the msgA PUSCH frequency-domain occasions are for the given index l of the OFDM symbol. [00229] Mapping Between PRACH Preamble and msgA PUSCH [00230] The msgA PUSCH transmission occasion maps to the PRACH preamble transmission occasion based on the Random-Access (RA) Radio RNTI nRNTI and Random-Access Preamble Identity (RAPI) n_RAPID indexes. [00231] The RA-RNTI is computed in accordance with the following equation: RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id [00232] s_id – is the index of the first OFDM symbol of the PRACH occasion [00233] t_id – is the index of the first slot of the PRACH occasion [00234] f_id – is the index of the PRACH occasion in the frequency domain [00235] ul_carrier_id – 0 for normal carrier and 1 for Supplementary Uplink (SUL) [00236] The RA-RNTI maps the msgA time-frequency occasion to the PRACH preamble time-frequency occasion. The RAPID is the index of the random-access PRACH preamble transmitted for the msgA PUSCH. Therefore, the RPAID maps the msgA time-frequency occasion to the PRACH preamble index. The msgA PUSCH codeword is scrambled prior to modulation using the initial scrambling seed value equal to c_init. The c_init is computed as follows:

[00237] In addition to the RA-RNTI and RAPID identities, the n_ID parameter is used. The n_ID may be assigned to the msgA-DataScramblingIndex provided as a part of the configuration structure. If msgA-DataScramblingIndex is not provided, then n_ID is assigned to the Physical Cell ID (PCI). The n_ID identifies an intendent serving gNB. [00238] Proposed PRACH Signal Structure for NR Positioning [00239] UL SRS Reference Signal Transmission [00240] An UL SRS for positioning is introduced as a part of the step A transmission and a DL PRS as a part of the step B transmission. [00241] In the time domain, an UL SRS reference signal may occupy the N_symb ^SRS consecutive OFDM symbols within the time slot. The UL SRS time domain occasion is defined by the starting OFDM symbol index l₀ within the time slot. [00242] FIG. 19 illustrates UL SRS time-domain occasions in accordance with some embodiments. That is, FIG. 19 shows an example of considered configuration and the corresponding time-domain UL SRS occasions. In the provided example l₀ = 4 and N_symb ^SRS = 4. [00243] In frequency domain, an UL SRS reference signal may occupy mSRS PRBs. The UL SRS transmission occasion in frequency domain is defined by the index kf, kf = 0, 1, …, M-1. The total number of the frequency occasions can be defined as follows:

[00244] where: [00245] N_SC ^RB = 12 – is the total number of subcarriers per PRB [00246] m_SRS – is the total number of PRBs allocated for the UL SRS transmission [00247] K_TC – is the comb size of the UL SRS transmission, it defines the step size for the subcarrier’s assignment [00248] FIG. 20 illustrates UL SRS frequency-domain occasions in accordance with some embodiments. In FIG. 20, the UL SRS frequency-domain occasions are for the given index l of the OFDM symbol. [00249] There are a number of options for the UL SRS reference signal transmission in combination with a PRACH preamble and msgA PUSCH. [00250] Option 1 [00251] In option 1, a UE may transmit the UL SRS reference signal using the same time-domain occasions as for PRACH preamble. In that case, the number of symbols allocated for a PRACH preamble is equal to the number of symbols allocated for the UL SRS reference signal, i.e. N_dur ^RA = N_symb ^SRS. [00252] The number of frequency-domain occasions allocated for a PRACH preamble transmission is equal to the number of frequency-domain occasions allocated for the UL SRS transmission, i.e. msgA-RO-FDM = K_TC. These occasions are FDMed in the frequency domain. [00253] FIG. 21A illustrates a first UL SRS transmission in accordance with some embodiments. FIG. 21B illustrates a second UL SRS transmission in accordance with some embodiments. That is, FIGS. 21A and 21B show sub options for option 1 for the UL SRS transmission FDMed with a PRACH preamble. [00254] In FIG. 21A, a PRACH preamble occupies the lower part of the signal spectrum and the UL SRS reference signal occupies an upper part. In FIG. 21B, a PRACH preamble occupies the upper part of the signal spectrum and the UL SRS reference signal occupies a lower part. In both cases a PRACH preamble and the UL SRS can be separated by a guard band denoted as a GuardBand in FIGS. 21A and 21B. The GuardBand parameter may be assigned to zero or greater than zero and defined in the PRB units. [00255] FIG. 22A illustrates a first resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. FIG. 22B illustrates a second resource mapping between PRACH frequency-domain occasions and UL SRS frequency- domain occasions in accordance with some embodiments. That is, FIGS. 22A and 22B show resource mapping between a PRACH preamble frequency- domain occasions and the UL SRS frequency-domain occasions in option 1. In the provided example, msgA-RO-FDM = 4 and K_TC =4. [00256] A PRACH preamble frequency-domain occasions are numbered from n_RA = 0 up to n_RA = 3 and highlighted by a different color. These PRACH frequency-domain occasions are mapped to the UL SRS frequency-domain occasions, where n_RA = 0 is mapped to the shift = 0, n_RA = 1 is mapped to the shift = 1, n_RA = 2 is mapped to the shift = 2, and n_RA = 3 is mapped to the shift = 3. Any other mapping of the n_RA and the shift values is possible. [00257] Option 2 [00258] In option 2, a UE may transmit the UL SRS reference signal using the same time-domain occasions as for msgA PUSCH. In that case, the number of symbols allocated for the msgA PUSCH is equal to the number of symbols allocated for the UL SRS reference signal, i.e. L = N_symb ^SRS. [00259] The number of frequency-domain occasions allocated for the msgA PUSCH transmission is equal to the number of frequency-domain occasions allocated for the UL SRS transmission, i.e. nrofMsgA-PO-FDM = K_TC. These occasions are FDMed in the frequency domain. [00260] FIG. 23A illustrates a third UL SRS transmission in accordance with some embodiments. FIG. 23B illustrates a fourth UL SRS transmission in accordance with some embodiments. That is, FIGS. 23A and 23B show sub options of option 2 for the UL SRS transmission FDMed with the msgA PUSCH. [00261] In FIG. 23A, the msgA PUSCH occupies the lower part of the signal spectrum and the UL SRS reference signal occupies an upper part. In FIG. 23B, the msgA PUSCH occupies the upper part of the signal spectrum and the UL SRS reference signal occupies a lower part. In both cases the msgA PUSCH and the UL SRS can be separated by a guard band denoted as a GuardBand in FIGS. 23A and 23B. The GuardBand parameter may be assigned to zero or greater than zero and defined in the PRB units. [00262] FIG. 24A illustrates a third resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. FIG. 24B illustrates a fourth resource mapping between PRACH frequency-domain occasions and UL SRS frequency- domain occasions in accordance with some embodiments. That is, FIGS. 24A and 24B show resource mapping between msgA PUSCH frequency-domain occasions and the UL SRS frequency-domain occasions in option 2. In FIGS. 24A and 24B, nrofMsgA-PO-FDM = 4 and K_TC =4. [00263] The msgA PUSCH frequency-domain occasions are numbered from n_f = 0 up to n_f = 3 and highlighted by a different color. These msgA PUSCH frequency-domain occasions are mapped to the UL SRS frequency- domain occasions, where n_f = 0 is mapped to the shift = 0, n_f = 1 is mapped to the shift = 1, n_f = 2 is mapped to the shift = 2, and n_f = 3 is mapped to the shift = 3. Any other mapping of the n_f and the shift values is possible. [00264] Option 3 [00265] In option 3, a UE may transmit the UL SRS reference signal using a single or multiple time slots not used for a PRACH preamble and msgA PUSCH transmission. Two parameters UL-SRS-TimeDomainOffset and nrofSlotsUL-SRS are used to specify the UL SRS time slot occasions. UL-SRS- TimeDomainOffset defines the time domain offset of UL SRS slots relative to a PRACH slot. nrofSlotsUL-SRS defines the number of successive time slots occupied by the UL SRS reference signal. [00266] FIG. 25 illustrates another mapping between a PRACH time slot and UL SRS time slots in accordance with some embodiments. In FIG. 25 UL- SRS-TimeDomainOffset = 1 and nrofSlotsUL-SRS = 2. In that case, the number of time-domain occasions for a PRACH preamble shown in FIG. 14 is equal to the number of time-domain occasions allocated for the UL SRS reference signal. [00267] FIG. 26A illustrates a first mapping between PRACH preamble time-domain occasions and UL SRS time-domain occasions in accordance with some embodiments. FIG. 26B illustrates a second mapping between PRACH preamble time-domain occasions and UL SRS time-domain occasions in accordance with some embodiments. In FIGS. 26A and 26B, N_dur ^RA = 2 and N_symb ^SRS = 2. In general case the UL SRS reference signal may occupy multiple time slots and N_dur ^RA may be not equal to the N_symb ^SRS. The UL SRS time- domain occasions are separated by the GuardPeriod. The GuardPeriod parameter may be assigned to zero or greater than zero and defined in the OFDM symbol units. [00268] A PRACH preamble time-domain occasions are numbered from nt = 0 up to nt = 3 and highlighted by a different color. These PRACH time- domain occasions are mapped to the UL SRS time-domain occasions, where nt = 0 is mapped to the n_t ^SRS = 0, n_t = 1 is mapped to the n_t ^SRS = 1, nt = 2 is mapped to the n_t ^SRS = 2, and nt = 3 is mapped to the n_t ^SRS = 3. Any other mapping of the nt and the n_t ^SRS values is possible. The number of frequency-domain occasions allocated for a PRACH preamble transmission is equal to the number of frequency-domain occasions allocated for the UL SRS transmission, i.e. msgA- RO-FDM = K_TC. [00269] FIG. 27 illustrates another resource mapping between PRACH frequency-domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. In FIG. 27, msgA-RO-FDM = 4 and K_TC =4. [00270] A PRACH preamble frequency-domain occasions are numbered from n_RA = 0 up to n_RA = 3 and highlighted by a different color. These PRACH frequency-domain occasions are mapped to the UL SRS frequency-domain occasions, where n_RA = 0 is mapped to the shift = 0, n_RA = 1 is mapped to the shift = 1, n_RA = 2 is mapped to the shift = 2, and n_RA = 3 is mapped to the shift = 3. Any other mapping of the n_RA and the shift values is possible. [00271] Option 4 [00272] In option 4, a UE may transmit the UL SRS reference signal using a single or multiple time slots not used for a PRACH preamble and msgA PUSCH transmission. Two parameters UL-SRS-TimeDomainOffset and nrofSlotsUL-SRS are used to specify UL SRS time slot occasions. UL-SRS- TimeDomainOffset defines the time domain offset of UL SRS slots relative to the msgA PUSCH first slot. nrofSlotsUL-SRS defines the number of successive time slots occupied by the UL SRS reference signal. [00273] FIG. 28 illustrates a mapping between a msgA PUSCH first time slot and UL SRS time slots in accordance with some embodiments. In FIG. 28 UL-SRS-TimeDomainOffset = 2 and nrofSlotsUL-SRS = 2. In that case, the number of time-domain occasions for the msgA PUSCH shown in FIG. 17 is equal to the number of time-domain occasions allocated for the UL SRS reference signal. [00274] FIG. 29A illustrates a first mapping between msgA PUSCH time- domain occasions and UL SRS time-domain occasions in accordance with some embodiments. FIG. 29B illustrates a second mapping between msgA PUSCH time-domain occasions and UL SRS time-domain occasions in accordance with some embodiments. In FIG. 29A and 29B, L = 2 and N_symb ^SRS = 2. In general, the UL SRS reference signal and msgA PUSCH may occupy multiple time slots and L may be not equal to the N_symb ^SRS. [00275] The UL SRS time-domain occasions are separated by the GuardPeriod. The GuardPeriod parameter may be assigned to zero or greater than zero and defined in the OFDM symbol units. The msgA PUSCH time- domain occasions are separated by the guardPeriodMsgA-PUSCH. The guardPeriodMsgA-PUSCH parameter may be assigned to zero or greater than zero and defined in the OFDM symbol units. In general case guardPeriodMsgA- PUSCH may not be equal to the GuardPeriod. [00276] The msgA PUSCH time-domain occasions are numbered from n_t ^msgA = 0 up to n_t ^msgA = 3 and highlighted by a different color. These msgA PUSCH time-domain occasions are mapped to the UL SRS time-domain occasions, where n_t ^msgA = 0 is mapped to the n_t ^SRS = 0, nt^msgA = 1 is mapped to the n_t ^SRS = 1, n_t ^msgA = 2 is mapped to the n_t ^SRS = 2, and n_t ^msgA = 3 is mapped to the n_t ^SRS = 3. Any other mapping of the n_t ^msgA and the n_t ^SRS values is possible. [00277] The number of frequency-domain occasions allocated for the msgA PUSCH transmission is equal to the number of frequency-domain occasions allocated for the UL SRS transmission, i.e. nrofMsgA-PO-FDM = K_TC. FIG. 30 illustrates resource mapping between msgA PUSCH frequency- domain occasions and UL SRS frequency-domain occasions in accordance with some embodiments. In FIG. 30, nrofMsgA-PO-FDM = 4 and K_TC =4. [00278] The msgA PUSCH frequency-domain occasions are numbered from n_f = 0 up to n_f = 3 and highlighted by a different color. These msgA PUSCH frequency-domain occasions are mapped to the UL SRS frequency- domain occasions, where n_f = 0 is mapped to the shift = 0, n_f = 1 is mapped to the shift = 1, n_f = 2 is mapped to the shift = 2, and n_f = 3 is mapped to the shift = 3. Any other mapping of the n_f and the shift values is possible. [00279] DL PRS Reference Signal Transmission [00280] In the time domain, a DL PRS reference signal may occupy the LPRS consecutive OFDM symbols within the time slot. The DL PRS time domain occasion is defined by the starting OFDM symbol index l_start ^PRS within the time slot. FIG. 31 illustrates DL PRS time-domain occasions in accordance with some embodiments. In FIG. 31 l_start ^PRS = 4 and LPRS = 4. [00281] In the frequency domain, a DL PRS reference signal may occupy DL-PRS-ResourceBandwidth PRBs. The UL SRS transmission occasion in frequency domain is defined by the index k_f, k_f = 0, 1, …, M-1. The total number of the frequency occasions can be defined as follows:

[00282] where: [00283] N_SC ^RB = 12 – is the total number of subcarriers per PRB [00284] DL-PRS-ResourceBandwidth – is the total number of PRBs allocated for the DL PRS transmission [00285] K_comb ^PRS – is the comb size of the DL PRS transmission, it defines the step size for the subcarrier’s assignment [00286] FIG. 32 illustrates DL PRS frequency-domain occasions in accordance with some embodiments. As shown, FIG. 32 is for the given index l of the OFDM symbol. DL-PRS-PointA defines the start PRB of the DL PRS transmission in frequency domain. k_offset ^PRS defines an offset within the K_comb ^PRS size period. k’(l) defines a time dependent frequency offset. [00287] For the DL PRS reference signal transmission in combination with the msgB PDSCH/PDCCH, a serving gNB and a single or multiple neighbor gNBs may transmit the DL PRS reference signal using a single or multiple time slots not used for the msgB transmission. Two parameters DL- PRS-TimeDomainOffset and nrofSlotsDL-PRS are used to specify the DL PRS time slot occasions. DL-PRS-TimeDomainOffset defines the time domain offset of DL PRS slots relative to the msgB slot. nrofSlotsDL-PRS defines the number of successive time slots occupied by the DL PRS reference signal. [00288] FIG. 33 illustrates mapping between msgB time slot and DL PRS time slot in accordance with some embodiments. In FIG. 33 DL-PRS- TimeDomainOffset = 1 and nrofSlotsDL-PRS = 1. The msgA may contain the list of the Physical Cell Identifiers (PCIs) corresponding to a serving gNB and a single or multiple neighbour gNBs. This list of the PCIs identifies the intendent recipients of the UL SRS reference signal. In case of the DL-TDOA or DL RTT solicited transmission, it also defines the DL PRS signal structure. [00289] FIG. 34 illustrates a DL PRS signal structure in accordance with some embodiments. In FIG. 34, the number of PCIs is equal to 4 and the K_comb ^PRS = 4. Each of the PCIs corresponds to its own unique frequency offset k_offset ^PRS, where PCI #0 is mapped to the k_offset ^PRS = 0, PCI #1 is mapped to the k_offset ^PRS = 1, PCI #2 is mapped to the k_offset ^PRS = 2, and PCI #3 is mapped to the k_offset ^PRS = 3. Any other mapping of the PCIs and the offset values is possible. In general, the DL PRS transmission shown in FIG. 34 can be repeated within the time slot and/or over the different time slots. nrofMsgB-PO-PerSlot defines the total number of DL PRS time-domain occasions within the slot. [00290] FIG. 35 illustrates a DL PRS transmission using multiple time slots and multiple time-domain occasions in accordance with some embodiments. In FIG. 35, nrofMsgB-PO-PerSlot = 2 and nrofSlotsDL-PRS = 2. The DL PRS time-domain occasions are separated by the GuardPeriod. The GuardPeriod parameter may be assigned to zero or greater than zero and defined in the OFDM symbol units. [00291] Although an embodiment has been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the present disclosure. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof show, by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled. [00292] The subject matter may be referred to herein, individually and/or collectively, by the term “embodiment” merely for convenience and without intending to voluntarily limit the scope of this application to any single inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. [00293] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, UE, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. [00294] The Abstract of the Disclosure is provided to comply with 37 C.F.R. §1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

Claims

CLAIMS What is claimed is: 1. An apparatus for a 5^th generation NodeB (gNB), the apparatus comprising: processing circuitry configured to: decode, from a user equipment (UE) during a physical random access channel (PRACH) procedure, uplink (UL) transmissions comprising a PRACH preamble and an UL Sounding Reference Signal (SRS); and encode, for transmission to the UE, a downlink (DL) transmission in response to reception of the UL SRS, at least one of: the UL transmissions comprising an UL Sounding Reference Signal (SRS) or the DL transmission comprising a DL Positioning Reference Signal (PRS); a^nd a memory configured to store the PRACH preamble.

2. The apparatus of claim 1, wherein the PRACH procedure is a two-step PRACH procedure in which the UL transmissions further comprise a msgA payload in a Physical Uplink Control Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH).

3. The apparatus of claim 2, wherein the DL transmission further comprises a msgB payload in a Physical Downlink Control Channel (PDCCH) or a Physical Downlink Shared Channel (PDSCH), the msgB payload comprising at least one of a contention resolution or random-access response.

4. The apparatus of claim 3, wherein the processing circuitry is further configured to: encode, for transmission to a neighbor gNB, a first backhaul transmission that contains the msgA payload and does not contain the UL SRS, and decode, from the neighbor gNB, a second backhaul transmission that contains the msgB payload and does not contain the DL PRS.

5. The apparatus of claim 3, wherein the processing circuitry is further configured to encode, for transmission to the UE, a System Information Block (SIB) or Long-Term Evolution (LTE) Positioning Protocol (LPP) assistance data that contains a DL PRS configuration, the DL PRS configuration comprising: a time domain offset of a DL PRS slot for transmission of the PRS in time slots relative to a msgB slot for transmission of the msgB payload, a number of successive time slots occupied by the DL PRS, a PRS sequence of the DL PRS, a first DL PRS orthogonal frequency domain multiplexing (OFDM) symbol index within the DL PRS slot, a total number of consecutive OFDM symbols of the DL PRS, a comb size of the DL PRS, a resource element offset of the DL PRS, and a total bandwidth that can be allocated for the DL PRS in resource block units.

6. The apparatus of claim 3, wherein the msgB payload comprises: a time domain offset of a DL PRS slot for transmission of the PRS in time slots relative to a msgB slot for transmission of the msgB payload, a number of successive time slots occupied by the DL PRS, a first DL PRS orthogonal frequency domain multiplexing (OFDM) symbol index within the DL PRS slot, a total number of consecutive OFDM symbols of the DL PRS, a transmit-receive time difference between a transmission time of the DL PRS and a reception time of the UL SRS, and a total bandwidth that can be allocated for the DL PRS in resource block units.

7. The apparatus of claim 2, wherein the msgA payload comprises: a list of Physical Cell Identities (PCIs) that indicates intendent recipients of the msgA payload and includes a PCI of the gNB, a TypeOfMeasurement parameter that includes one of: a round trip time (RTT), uplink Time Difference of Arrival (UL-TDOA), or downlink Time Difference of Arrival (DL-TDOA), and a total bandwidth allocated for a DL PRS transmission if the TypeOfMeasurement parameter is RTT or DL-TDOA.

8. The apparatus of claim 2, wherein the processing circuitry is further configured to encode, for transmission to the UE, a System Information Block (SIB) or Long-Term Evolution (LTE) Positioning Protocol (LPP) assistance data that contains a UL SRS configuration, the UL SRS configuration comprising: a time domain offset of an SRS slot for transmission of the SRS in time slots relative to a PRACH slot for transmission of the PRACH preamble, a number of successive time slots occupied by the UL SRS, a starting position in a time domain of the UL SRS, a total number of consecutive orthogonal frequency domain multiplexing (OFDM) symbols of the UL SRS, a frequency-domain starting position of the UL SRS, a comb size of the UL SRS, a total bandwidth that can be allocated for the UL SRS in resource block units, a sequence identifier (ID) of the UL SRS, and a parameter identifying group or sequence hopping type of UL SRS.

9. The apparatus of claim 1, wherein: the UL SRS occupies a number of consecutive orthogonal frequency domain multiplexing (OFDM) symbols within an UL SRS time slot, a UL SRS time domain occasion defined by a starting OFDM symbol index within the UL SRS time slot, and the UL SRS occupies a number of Physical Resource Blocks (PRBs), a UL SRS frequency domain occasion defined by a frequency domain index, a total number of frequency domain occasions being a total number of PRBs allocated for the UL SRS multiplied by a total number of subcarriers per PRB and divided by a comb size of the UL SRS.

10. The apparatus of claim 1, wherein: the UL SRS and the PRACH preamble are transmitted using a same time-domain occasion, a number of orthogonal frequency domain multiplexing (OFDM) symbols allocated for the UL SRS is equal to a number of OFDM symbols allocated for the PRACH preamble, a number of frequency-domain occasions allocated for the UL SRS is equal to a number of frequency-domain occasions allocated for the PRACH preamble, the frequency-domain occasions for the UL SRS frequency domain multiplexed with the frequency-domain occasions for the PRACH preamble, and the PRACH preamble and the UL SRS are separated by a guard band.

11. The apparatus of claim 1, wherein: the PRACH procedure is a two-step PRACH procedure in which the UL transmissions further comprise a msgA payload, the UL SRS and the msgA payload are transmitted using a same time- domain occasion, a number of orthogonal frequency domain multiplexing (OFDM) symbols allocated for the UL SRS is equal to a number of OFDM symbols allocated for the msgA payload, a number of frequency-domain occasions allocated for the UL SRS is equal to a number of frequency-domain occasions allocated for the msgA payload, the frequency-domain occasions for the UL SRS frequency domain multiplexed with the frequency-domain occasions for the msgA payload, and the msgA payload and the UL SRS are separated by a guard band.

12. The apparatus of claim 1, wherein: the PRACH procedure is a two-step PRACH procedure in which the UL transmissions further comprise a msgA payload transmitted on a physical uplink shared channel (PUSCH), the UL SRS and the msgA payload are transmitted using a different time slot than the msgA payload and the PRACH preamble, and the processing circuitry is further configured to encode, for transmission to the UE, a first parameter that indicates a time domain offset of UL SRS slots relative to a PRACH slot and a second parameter that indicates a number of successive time slots occupied by the UL SRS.

13. The apparatus of claim 12, wherein: the UL SRS occupies multiple time slots, UL SRS time-domain occasions are separated by a GuardPeriod, and a number of frequency-domain occasions allocated for the PRACH preamble is equal to a number of frequency-domain occasions allocated for the UL SRS.

14. The apparatus of claim 1, wherein: the PRACH procedure is a two-step PRACH procedure in which the UL transmissions further comprise a msgA payload transmitted on a physical uplink shared channel (PUSCH), the UL SRS and the msgA payload are transmitted using a different time slot than the msgA payload and the PRACH preamble, and the processing circuitry is further configured to encode, for transmission to the UE, a first parameter that indicates a time domain offset of UL SRS slots relative to a first msgA slot and a second parameter that indicates a number of successive time slots occupied by the UL SRS.

15. The apparatus of claim 14, wherein: the UL SRS occupies multiple time slots, UL SRS time-domain occasions are separated by a GuardPeriod, and a number of frequency-domain occasions allocated for the msgA payload is equal to a number of frequency-domain occasions allocated for the UL SRS.

16. The apparatus of claim 1, wherein: the DL transmission further comprises a msgB payload, the DL PRS occupies multiple consecutive orthogonal frequency domain multiplexing (OFDM) symbols within a DL PRS time slot, the DL PRS occupies Physical Resource Blocks (PRBs) having DL PRS time slot occasions defined by a first parameter that indicates a time domain offset of DL PRS slots relative to a msgB slot and a second parameter that indicates a number of successive time slots occupied by the DL PRS, and the DL PRS time slot occasions are separated by a guard period when the DL PRS occupies multiple time slots.

17. An apparatus for a user equipment (UE), the apparatus comprising: processing circuitry configured to: encode, to a 5^th generation NodeB (gNB), uplink (UL) transmissions comprising a physical random access channel (PRACH) preamble and a msgA payload; and decode, from the gNB, a downlink (DL) transmission in response to transmission of the UL transmissions, the DL transmission comprising a msgB payload, at least one of: the UL transmissions comprising an UL Sounding Reference Signal (SRS) or the DL transmission comprising a D^{L Positioning Reference Signal (PRS); and} a memory configured to store the PRACH preamble.

18. The apparatus of claim 17, wherein the processing circuitry is further configured to decode, from the gNB, a System Information Block (SIB) or Long-Term Evolution (LTE) Positioning Protocol (LPP) assistance data that contains a UL SRS configuration and a DL PRS configuration, the UL SRS configuration comprising a time domain offset of an SRS slot for transmission of the SRS in time slots relative to a PRACH slot for transmission of the PRACH preamble and a number of successive time slots occupied by the UL SRS, the DL PRS configuration comprising a time domain offset of a DL PRS slot for transmission of the PRS in time slots relative to a msgB slot for transmission of the msgB payload and a number of successive time slots occupied by the DL PRS.

19. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a 5^th generation NodeB (gNB), the one or more processors to configure the gNB to, when the instructions are executed: decode, from a user equipment (UE), uplink (UL) transmissions comprising a PRACH preamble, a msgA payload, and an UL Sounding Reference Signal (SRS); and encode, for transmission to the UE, a downlink (DL) transmission in response to reception of the UL SRS, the DL transmission comprising a msgB payload and a DL Positioning Reference Signal (PRS).

20. The medium of claim 19, wherein the one or more processors further configure the gNB to, when the instructions are executed encode, for transmission to the UE, a System Information Block (SIB) or Long-Term Evolution (LTE) Positioning Protocol (LPP) assistance data that contains a UL SRS configuration and a DL PRS configuration, the UL SRS configuration comprising a time domain offset of an SRS slot for transmission of the SRS in time slots relative to a PRACH slot for transmission of the PRACH preamble and a number of successive time slots occupied by the UL SRS, the DL PRS configuration comprising a time domain offset of a DL PRS slot for transmission of the PRS in time slots relative to a msgB slot for transmission of the msgB payload and a number of successive time slots occupied by the DL PRS.