Autonomous timing advance estimation in idle mode for 6G UE

Abstract

Various embodiments of the present disclosure relate to apparatuses, devices, methods, and computer readable storage media for autonomous timing advance estimation in idle mode of 6G UE. The apparatus comprises: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: receiving physical layer signals from a plurality of user equipments; determining a corresponding timing advance measurement based at least in part on the received physical layer signal; and selecting, based at least in part on the one or more parameters, at least one of the respective timing advance measurements for determining a timing advance for the apparatus for transmitting a signal to the network equipment.

Description

TECHNICAL FIELD

[0001] Example and non-limiting embodiments relate generally to timing advance estimation, and more particularly, to timing advance for user equipment in idle mode. Brief description of the development of the prior art

[0002] Estimating timing advance for equipment for communicating with a base station is generally known. SUMMARY

[0003] The following summary is merely intended to illustrate example. The summary does not intend to limit the scope of the claims.

[0004] According to one aspect, there is provided an example apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: determining information about a physical layer signal to be transmitted from a user equipment; receiving, by the apparatus, the physical layer signal transmitted from the user equipment; and determining, by the apparatus, a timing advance for the apparatus for transmitting a signal to network equipment based on the determined information and the reception of the physical layer signal.

[0005] According to another aspect, there is provided an example method comprising: determining, by an apparatus, information about a physical layer signal to be transmitted from a user equipment; receiving, by the apparatus, the physical layer signal transmitted from the user equipment; and determining, by the apparatus, a timing advance for the apparatus for transmitting a signal to network equipment based on the determined information and the reception of the physical layer signal.

[0006] According to another aspect, there is provided an example apparatus comprising: means for determining information about a physical layer signal to be transmitted from a user equipment; means for receiving the physical layer signal transmitted from the user equipment; and means for determining a timing advance for the apparatus for transmitting a signal to network equipment based on the determined information and the reception of the physical layer signal.

[0007] According to another aspect, there is provided an example program storage device readable by an apparatus, the device tangibly embodying a program of instructions executable by the apparatus for performing operations, the operations comprising: determining information about a physical layer signal to be transmitted from a user equipment; receiving the physical layer signal transmitted from the user equipment; and determining a timing advance for the apparatus for transmitting a signal to network equipment based on the determined information and the reception of the physical layer signal.

[0008] According to another aspect, an example apparatus is provided that includes at least one processor; and at least one memory that stores instructions, which when executed by the at least one processor, cause the apparatus to perform: determining information related to a physical layer signal to be received by the apparatus, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus; and transmitting, by the apparatus, the information to a second user equipment, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment.

[0009] According to another aspect, an example method is provided that includes determining information related to a physical layer signal to be received by the apparatus, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus; and transmitting, by the apparatus, the information to a second user equipment, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment.

[0010] According to another aspect, an example apparatus is provided that includes means for determining information related to a physical layer signal to be received by the apparatus, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus; and means for transmitting, by the apparatus, the information to a second user equipment, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment.

[0011] According to another aspect, an example program storage device readable by a apparatus tangibly embodying a program of instructions executable by the apparatus for performing operations, the operations including: determining information related to a physical layer signal to be received by the apparatus, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus; and transmitting, by the apparatus, the information to a second user equipment, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment.

[0012] According to another aspect, an example apparatus is provided that includes at least one processor; and at least one memory that stores instructions, which when executed by the at least one processor, cause the apparatus to perform: receiving physical layer signals from a plurality of user equipments; determining corresponding timing advance measurements based at least in part on the received physical layer signals; and selecting, based at least in part on one or more parameters, at least one of the corresponding timing advance measurements for determining a timing advance for the apparatus for transmitting signals to network equipment.

[0013] According to another aspect, an example method is provided that includes receiving physical layer signals from a plurality of user equipment; determining respective timing advance measurements based at least in part on the received physical layer signals; and selecting at least one of the respective timing advance measurements for use in determining a timing advance for transmitting signals to network equipment based at least in part on one or more parameters.

[0014] According to another aspect, an example apparatus is provided that includes means for receiving physical layer signals from a plurality of user equipment; means for determining respective timing advance measurements based at least in part on the received physical layer signals; and means for selecting at least one of the respective timing advance measurements for use in determining a timing advance for transmitting signals to network equipment based at least in part on one or more parameters.

[0015] According to another aspect, an example program storage device readable by a apparatus is provided that tangibly embodies a program of instructions executable by the apparatus to perform operations, the operations including receiving physical layer signals from a plurality of user equipment; determining respective timing advance measurements based at least in part on the received physical layer signals; and selecting at least one of the respective timing advance measurements for use in determining a timing advance for transmitting signals to network equipment based at least in part on one or more parameters.

[0016] According to another aspect, an example apparatus is provided that includes at least one processor; and at least one memory that stores instructions that, when executed by the at least one processor, cause the apparatus to perform operations comprising: determining a first timing advance pattern for transmitting signals from the apparatus to network equipment; determining a second timing advance pattern for transmitting signals from the apparatus to the network equipment; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on physical layer signals from one or more user equipment.

[0017] According to another aspect, an example method is provided that includes determining a first timing advance pattern for transmitting signals from the apparatus to network equipment; determining a second timing advance pattern for transmitting signals from the apparatus to the network equipment; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on physical layer signals from one or more user equipment.

[0018] According to another aspect, an example apparatus is provided that includes means for determining a first timing advance pattern for transmitting signals from the apparatus to network equipment; means for determining a second timing advance pattern for transmitting signals from the apparatus to the network equipment; and means for switching between the first timing advance pattern and the second timing advance pattern based at least in part on physical layer signals from one or more user equipments.

[0019] According to another aspect, an example of a program storage device readable by an apparatus, the program storage device tangibly embodying a program of instructions executable by the apparatus to perform operations, is provided that includes determining a first timing advance pattern for transmitting signals from the apparatus to network equipment; determining a second timing advance pattern for transmitting signals from the apparatus to the network equipment; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on physical layer signals from one or more user equipments.

[0020] According to some aspects, the subject matter of the independent claims is provided. Some further aspects are provided in the subject matter of the dependent claims. BRIEF DESCRIPTION OF DRAWINGS

[0021] The foregoing aspects and other features are explained in the following description, taken in connection with the accompanying drawings, wherein:

[0022] Figure 1 is a block diagram of one possible and non-limiting example system in which example embodiments can be practiced;

[0023] Figure 2A is a diagram illustrating a 4-step contention-based random access procedure;

[0024] Figure 2B is a diagram illustrating a 2-step RACH procedure;

[0025] Figure 3 is a diagram illustrating an NR RRC state machine with RRC state transitions;

[0026] Figure 4 is a diagram illustrating an example of relative locations of beams from network equipment and a user equipment;

[0027] Figure 5 is Figure 4 is a timing diagram corresponding to the user equipment locations illustrated in

[0028] Figure 6 is a diagram illustrating an example of relative locations of beams from network equipment and a user equipment;

[0029] Figure 7 is Figure 6 is a timing diagram corresponding to the user equipment locations illustrated in

[0030] Figure 8 is a diagram illustrating an example of relative locations of beams from network equipment and user equipment;

[0031] Figure 9 is a diagram illustrating an example of a beam directed to a user equipment;

[0032] Figure 10 is a diagram illustrating an example of relative locations of beams from network equipment and user equipment;

[0033] Figure 11 is a diagram illustrating an example signaling flow;

[0034] Figure 12 is a diagram illustrating an example method;

[0035] Figure 13 is a diagram illustrating an example method;

[0036] Figure 14 is a diagram illustrating an example method;

[0037] Figure 15 is a diagram illustrating an example method;

[0038] Figure 16 is a diagram illustrating an example method. DETAILED DESCRIPTION

[0039] The following abbreviations which can be found in the specification and / or drawings 3GPP Third Generation Partnership Project 5G Fifth Generation 5GC 5G Core Network 6G Sixth Generation AMF Access and Mobility Management Function BTS Base Transceiver Station CP Cyclic Prefix CU Central Unit D2D Device-to-Device DCI Downlink Control Information DL Downlink DMRS Demodulation Reference Signal DU Distributed Unit eNB (or eNodeB) Evolved Node B (e.g., LTE base station) EN-DC E-UTRA-NR Dual Connectivity en-gNB or En-gNB A node that provides NR user plane and control plane protocol terminations to a UE, and acts as a secondary node in EN-DC E-UTRA evolved universal terrestrial radio access, i.e., LTE radio access technology FDD frequency division duplex gNB (or gNodeB) next generation eNB GP guard period I / F interface ICI inter-subcarrier interference ISI inter-symbol interference LTE long term evolution MAC medium access control ML machine learning MME mobility management entity MSC message sequence chart N CS cyclic shift parameter ng or NG next generation ng-eNB or NG-eNB next generation eNB NR new radio N / W or NW network OFDMA orthogonal frequency division multiple access OTDOA observed time difference of arrival PD propagation delay PDCCH physical downlink control channel PDCP packet data convergence protocol PHY physical layer PRACH physical random access channel PUCCH physical uplink control channel RACH random access channel RAN radio access network RAR random access response Rel release RIS reconfigurable intelligent surface RLC radio link control RRH remote radio head RRC radio resource control RSRP reference signal received power RU radio unit Rx receiver SDAP service data adaptation protocol SGW serving gateway SIB system information block SMF session management function SRS sounding reference signal SSB synchronization signal block SS-RSRP synchronization signal reference signal received power TA timing advance TDD time division duplex TS technical specification Tx transmitter UE user equipment (e.g., wireless, typically mobile device) UL uplink UPF user plane function

[0040] turn to Figure 1 The figure illustrates a block diagram of one possible and non-limiting example in which examples can be practiced. A user equipment (UE) 110, a radio access network (RAN) node 170, and network element(s) 190 are shown. Examples of network equipment, network device, or network entity can be understood to include at least a portion of a transmission reception point or cell or gNB or node. In Figure 1 In the example of FIG. 1, a user equipment (UE) 110 is in wireless communication with a wireless network 100. The UE is a wireless device that can access the wireless network 100. The UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver, Rx, 132 and a transmitter, Tx, 133. The one or more buses 127 can be address, data, or control buses, and can include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, optical fiber or other optical communication device, and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a module 140, which includes one or both of portions 140-1 and / or 140-2, which can be implemented in a variety of ways. The module 140 can be implemented in hardware as module 140-1, such as being implemented as part of the one or more processors 120. The module 140-1 can also be implemented as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 140 can be implemented as module 140-2, which is implemented as computer program code 123 and executed by the one or more processors 120. For example, the one or more memories 125 and computer program code 123 can be configured to, with the one or more processors 120, cause the user equipment 110 to perform one or more of the operations according to the teachings herein. The UE 110 communicates with the RAN node 170 via a wireless link 111.

[0041] In this example, the RAN node 170 is a base station that provides access to wireless network 100 for wireless devices such as UE 110. The RAN node 170 can be, for example, a base station for 5G, also referred to as New Radio (NR). In 5G, the RAN node 170 can be an NG-RAN node, which is defined to be a gNB or ng-eNB. A gNB is a node that terminates the NR user plane and control plane protocol terminations toward a UE and connects to a 5GC (e.g., network element(s) 190) via an NG interface. An ng-eNB is a node that terminates the E-UTRA user plane and control plane protocol terminations toward a UE and connects to a 5GC via an NG interface. The NG-RAN node can include multiple gNBs, which can also include a central unit (CU) (gNB-CU) 196 and a distributed unit (DU) (gNB-DU), of which a DU 195 is shown. Note that the DU can include or be coupled to and control a radio unit (RU). The gNB-CU is a logical node that hosts the RRC, SDAP, and PDCP protocols of the gNB or the RRC and PDCP protocols of the en-gNB that control the operation of one or more gNB-DUs. The gNB-CU terminates the Fl interface with the gNB-DU. The Fl interface is shown as reference 198, although reference 198 also shows links between remote elements of the RAN node 170 and centralized elements of the RAN node 170, such as between gNB-CU 196 and gNB-DU 195. The gNB-DU is a logical node that hosts the RLC, MAC, and PHY layers of the gNB or en-gNB and whose operation is partially controlled by the gNB-CU. One gNB-CU supports one or more cells. One cell is supported by only one gNB-DU. The gNB-DU terminates the Fl interface 198 with the gNB-CU. Note that the DU 195 is considered to include the transceiver 160, e.g., as part of a RU, although some examples in relation thereto can have the transceiver 160 as part of a separate RU, e.g., under the control of and connected to the DU 195. The RAN node 170 can also be an eNB (Evolved Node B) base station, for LTE (Long Term Evolution), or any other suitable base station or node.

[0042] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces ((N / W)I / F(s)) 161, and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver, Rx, 162 and a transmitter, Tx, 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The CU 196 can include the processor(s) 152, the memory(ies) 155, and the network interface(s) 161. Note that the DU 195 can also contain its own memory / memory(ies) and processor(s) and / or other hardware, but these are not shown.

[0043] The RAN node 170 includes a module 150, which includes one or both of portions 150-1 and / or 150-2, which can be implemented in a variety of ways. The module 150 can be implemented in hardware as module 150-1, such as being implemented as part of the processor(s) 152. The module 150-1 can also be implemented as an integrated circuit or through other hardware such as a programmable gate array. In another example, the module 150 can be implemented as module 150-2, which is implemented as computer program code 153 and executed by the processor(s) 152. For instance, the memory(ies) 155 and the computer program code 153 are configured to, with the processor(s) 152, cause the RAN node 170 to perform one or more of the operations described herein. Note that the functionality of the module 150 can be distributed, such as between the DU 195 and the CU 196, or implemented only in the DU 195.

[0044] The network interface(s) 161 communicate through a network, such as via links 176 and 131. Two or more gNBs 170 can communicate using, for example, link 176. The link 176 can be wired or wireless or both and can implement, for example, an Xn interface for 5G, an X2 interface for LTE, or other suitable interface for other standards.

[0045] The one or more buses 157 can be address, data, or control buses, and can include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, fiber optics or other optical communication devices, wireless channels, and the like. For example, the one or more transceivers 160 can be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 for a gNB implementation for 5G, where other elements of the RAN node 170 can be physically located in a different location from the RRH / DU, and the one or more buses 157 can be implemented, in part, as, for example, fiber optic cables or other suitable network connections to connect the other elements of the RAN node 170 (e.g., central unit (CU), gNB-CU) to the RRH / DU 195. Reference 198 also indicates those suitable network links.

[0046] Note that the description herein indicates that a“cell” performs functions, but it should be clear that the equipment forming the cell will perform the functions. A cell constitutes a portion of a base station. That is, each base station can have multiple cells. For example, there can be three cells for a single carrier frequency and associated bandwidth, each cell covering one third of a 360 degree region, so that a single base station covers an approximately elliptical or circular region. Further, each cell can correspond to a single carrier, and a base station can use multiple carriers. Thus, if there are three 120 degree cells per carrier and there are two carriers, then a base station has a total of 6 cells.

[0047] The wireless network 100 can include a network element or multiple network elements 190, which can include core network functionality, and which provides connectivity to another network, such as a telephone network and / or a data communications network (e.g., the Internet) via link or links 181. Such core network functionality for 5G can include Access and Mobility Management Function(s) (AMF) and / or User Plane Function(s) (UPF) and / or Session Management Function(s) (SMF). Such core network functionality for LTE can include MME (Mobility Management Entity) / SGW (Serving Gateway) functionality. These are merely exemplary functionality that can be supported by the network element 190, and note that both 5G and LTE functionality can be supported. The RAN node 170 is coupled via a link 131 to the network element 190. The link 131 can be implemented, for example, as an NG interface for 5G, or an SI interface for LTE, or other suitable interface for other standards. The network element 190 includes one or more processors 175, one or more memories 171, and one or more network interfaces (N / W I / F) 180 interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to, with the one or more processors 175, cause the network element 190 to perform one or more operations.

[0048] Wireless network 100 can implement network virtualization, which is the process of combining hardware and software network resources and network functionality into a single, software- defined administrative entity, a virtual network. Network virtualization involves platform virtualization, which is often combined with resource virtualization. Network virtualization is classified as external, combining many networks, or parts of networks, into a virtual unit, or internal, providing software containers on a single system with network-like functionality. Note that the virtualized entities resulting from network virtualization still implement, to some extent, using hardware such as processors 152 or 175 and memories 155 and 171, and such virtualized entities can also produce technical effects.

[0049] Computer-readable memories 125, 155, and 171 can be of any type suitable to the local technical environment and can be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The computer-readable memories 125, 155, and 171 can be means for performing storage functions. The processors 120, 152, and 175 can be of any type suitable to the local technical environment, and can include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multi-core processor architectures, as non-limiting examples. The processors 120, 152, and 175 can be means for performing functions, such as control of UE 110, RAN node 170, and other functions in accordance with this specification.

[0050] In general, the various embodiments of User Equipment 110 can include, but are not limited to, cellular telephones such as smart phones, tablets, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, tablets with wireless communication capabilities, as well as portable units or terminals that incorporate combinations of such functions.

[0051] In accordance with that which is known in the art, Figure 2A A basic procedure for 4-step contention-based random access is shown, and Figure 2B A 2-step RACH procedure is shown. In 2-step RACH, MsgA combines the preamble signal (Msgl) and data signal (Msg3), and MsgB combines the random access response (Msg2) and contention resolution (Msg4). Further, in accordance with that which is known in the art, Figure 3RRC states including RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE are shown in the NR context.

[0052] In a 5G New Radio Radio Access Network (RAN), synchronization for a UE in idle mode to a gNB uses a synchronization signal block (SSB) transmitted in the downlink. However, due to the propagation distance between the gNB and the UE, the SSB reception at the UE is delayed compared to the time at the gNB. The delay is typically d / c seconds, where d is the distance between the gNB and the UE and c is the speed of light (3 x 10 8 Similarly, a transmission from the UE to the gNB will take time, such as d / c seconds, to reach the gNB. Thus, due to the round trip propagation delay of the signal, there is a time offset of approximately 2d / c between the gNB downlink radio frame transmitted at the gNB and the UE uplink radio frame received. The uplink of the 5G New Radio network is based on Orthogonal Frequency Division Multiple Access (OFDMA). To avoid inter-symbol interference (ISI) and inter-carrier interference (ICI) in OFDMA, the uplink transmissions from multiple users are received at the gNB within a cyclic prefix (CP) duration. Thus, correcting for this 2d / c time offset between the downlink and uplink frames for a UE helps avoid ISI and ICI. In the 5G New Radio RAN, a timing advance (TA) procedure is used to correct for this offset, where the uplink frames of the UE are advanced by 2d / c.

[0053] In the 5G New Radio RAN, the TA procedure is classified as an initial timing advance procedure or a continuous timing advance procedure.

[0054] The initial timing advance is necessary before a UE in idle mode can move to connected mode. The initial timing advance is performed as part of a random access procedure and advances the uplink timing at the UE to correct for the propagation delay between the gNB and the UE. During the random access procedure, a message 1 (see Figure 2A ) is transmitted from the UE to the gNB. Based on the timing of the received message 1 (preamble), the gNB determines a TA value and transmits the TA value to the UE using a message 2 (random access response (RAR)). The UE uses the TA value from the RAR and advances its uplink transmission. This procedure is referred to as the initial timing advance procedure. Because the gNB and the UE are not time aligned when the preamble is transmitted, a preamble format with a large cyclic prefix (CP) value and a large guard period (GP) value is used. In connected mode, the UE can move around the cell and the propagation delay can change. This requires updating the initial TA value. The TA at the gNB is updated by the gNB using a MAC control element (CE) containing a TA command and is referred to as the continuous timing advance procedure. The features described herein can primarily be intended for use in the initial timing advance procedure.

[0055] As noted above, the existing initial timing advance procedure specified in 3GPP results in signaling overhead and waste of time-frequency resources due to large CP and GP values. Various schemes have been proposed to perform TA autonomously, thereby reducing the cost due to the timing advance procedure. TA estimation methods also utilize positioning methods, as once the UE position is known relative to the gNB, the TA can be estimated.

[0056] Obtaining initial TA according to 3GPP always incurs a signaling overhead cost. This signaling overhead cost increases as the number of users increases. However, signaling is needed to estimate and then signal the TA value for each UE. Because the UE is not time-aligned with the gNB, the preamble must include a large CP and a large GP, which results in a cost in terms of time-frequency resources. These values are typically proportional to twice the cell radius. The time-frequency resources within the CP and GP are wasted resources. Similarly, in the case of the 2-step RACH procedure, a GP between PUSCH resources is needed due to the lack of timing synchronization between the gNB and the UE. These are also wasted resources. In addition to the cost incurred for initial TA estimation for idle mode UEs, a signaling cost is incurred to perform random access and TA update when the UE loses timing synchronization with the gNB during connected mode.

[0057] The PRACH (Physical Random Access Channel) preamble planning is also affected because the gNB and the UE are not time-aligned when transmitting the preamble. Preambles based on the same root sequence are preferred due to their superior auto-correlation properties. Preambles based on the same root sequence should be cyclically shifted N CS apart. The value of N CS depends on the value of zeroCorrelationZoneConfig. Because the preamble transmission is not time-aligned, N CS is proportional to twice the cell radius. Thus, based on the value of N CS , only a few preambles can be generated from a single root sequence. More root sequences can be used to configure up to 64 preambles, but the root sequences do not have good cross-correlation properties. Furthermore, using multiple root sequences per cell makes preamble sequence planning and interference management difficult in neighboring cells.

[0058] With the features of this document, if the UE can autonomously estimate its TA and pre-compensate for the propagation delay (PD) before transmitting the preamble, the time-frequency resources wasted due to the CP and GP of the preamble can be reduced, the initial TA signaling can be reduced or avoided, the preamble sequence planning can be made simpler, and the interference can be reduced.

[0059] An example method can be provided for autonomous timing advance (TA) estimation for idle mode UEs (e.g., with 6G capable of receiving beamforming, for example). TA for a candidate UE can be estimated by processing SRS (sounding reference signal) signals transmitted by one or more reference UEs located in the same base station beam as the candidate UE. In one example, SRS signals from at least two reference UEs are used. As used herein, a reference user equipment (“reference UE”) is a UE in connected state or mode that transmits SRS to a gNB and whose uplink frames are time advanced so that its propagation delay to the gNB is compensated. The proposed method uses SRS signals that are transmitted by the reference UEs as part of their usual UE-specific procedures (e.g., link adaptation). Thus, the proposed method can use existing SRS signals for an additional purpose; namely, timing advance estimation for a candidate UE. The SRS transmissions from the reference UEs are not requested by the candidate UE from the reference UEs. The SRS transmissions requested by the gNB from the reference UEs are also not intended exclusively with initiating TA measurements at the candidate UE. Rather, the SRS signals are for an auxiliary or additional purpose; a type of reuse. This additional purpose can also be referred to as an auxiliary or supplemental or backup purpose. Thus, the method incurs minimal signaling overhead as the SRS signals are already generated by another UE (reference UE) and the term “reference UE” is used herein only as a naming item to distinguish between UEs such as a candidate UE (in idle state) and a reference UE (in connected state). The reception beamforming capability of, for example, 6G UEs can be used to filter the TA measurements and provide a reliable TA estimate for the candidate UE.

[0060] Although the candidate UE receives and processes SRS from one or more reference UEs, the example method described herein can be referred to as “autonomous” because the candidate UE does not need to perform signaling with the gNB or the reference UEs to estimate its TA. The candidate UE can remain in its idle state while estimating its TA. In the context of implementing this method, for example, in a 6G RAN, the method is efficient because it reuses an existing physical layer signal (SRS signal from the reference UEs) transmitted from the reference UEs to the gNB as part of the reference UEs’ general physical layer procedures. Moreover, multiple candidate UEs can estimate their TAs based on SRS transmissions from a single reference UE (or at least some of the same reference UEs). In terms of standardization, the proposed method can add only a few bits to SIB and DCI signaling.

[0061] In other applications, the example method can enable an ML-based 6G BTS to adaptively control the N CS , CP, and GP values of the preamble format, whereby the PRACH load will decrease rather than increase as the number of users increases.

[0062] As noted above, the proposed method can be used to autonomously estimate TA, and thus is different from the regular TA scheme in 3GPP.

[0063] Figure 4 An example of a beamformed cell is shown. For simplicity, only three beams B1, B2, and B3 are shown. However, more or fewer beams can be provided. Beam B1 contains a candidate UE 110 whose TA is to be estimated. The candidate UE 110 is capable of receiving beamforming, and Figure 4 Three UE receiver beams B R An example of the steps that can be used to estimate the TA at the candidate UE 110 is as follows.

[0064] With reference to Figure 4 , the gNB 170 can select another UE 402 in the connected state (connected mode UE) in beam B1 that is already time aligned with the gNB 170 and located near the cell edge 404. This is also shown at 1202 in Figure 12 The cell edge is typically the farthest portion of the beam B1 in units of length of the beam. The time aligned here means that the uplink frame of the UE 402 is time advanced so that its propagation delay to the gNB is fully compensated. This UE 402 is referred to herein as the reference UE. The candidate UE 110 is in idle mode and, as shown in Figure 4 , is located at a distance “d” from the gNB 170. The reference UE 402 is located at a distance “d + 1” from the gNB 170. For simplicity of description, Figure 4 only one reference UE is shown in . However, as will be understood from the description below, more than two UEs can be present in the beam B1, and one or more of those UEs (that are in the connected state and time aligned with the gNB) can be used by the candidate UE 110 as reference UEs. In one type of example, the candidate UE 110 uses signals from multiple reference UEs for its autonomously determined timing advance (TA).

[0065] The reference UE 402 sends a sounding reference signal (SRS) to the gNB 170. This is also shown at 1204 in Figure 121208. The purpose of SRS transmission to the gNB is codebook-based link adaptation. However, other purposes for using SRS (such as beam management and / or antenna switching) are not excluded. These types of SRS can also be used with the features described herein. In the examples described below, it is assumed that the reference UE 402 sends aperiodic SRS. However, in alternative examples, the SRS can be periodic, semi-persistent or aperiodic. The SRS sent by the reference UE 402 to the gNB is part of the usual link adaptation process. With the features described herein, these types of conventional SRS signals can be additionally used for new purposes (also referred to herein as reuse) by the proposed method. This is in Figure 12 1210 is partially shown. C ) 110 can effectively receive 1210 the sounding reference signal (SRS) 1208 even if the signal 102 is received by the reference UE (UE R ) 402 is sent to the network device (gNB) 170, and the information from this signal 1208 is used for an additional new purpose. Thus, the same conventional SRS signal can be used for more than one purpose. In the example described below, the multiple uses include a first use with a first purpose by the gNB in ​​a conventional manner, and a second new use with a second new purpose by the candidate UE 110. The candidate UE 110 or gNB 170 does not request SRS transmission from the reference UE 402 for the exclusive purpose of this new, second use. Instead, the feature described herein enables the use of only the pre-existing purpose signal for the new, second purpose; TA measurements are enabled at the candidate UE 110. Thus, a single purpose signal can now be used for multiple purposes as described herein, and one of these uses can be used for a previously unintended recipient / user.

[0066] Similar to 5G, it is expected that 6G gNB will be able to request UE to send aperiodic SRS in specific symbols using DCI (Downlink Control Information) for downlink or uplink data transmission. Thus, gNB 170 can request reference UE 402 to send aperiodic SRS in specific symbols using DCI (Downlink Control Information) for downlink or uplink data transmission (e.g., see Figure 12 1207 in the common search space). Utilizing the features described herein, the gNB can simultaneously inform all UEs in beam B1 that the SRS transmission from the reference UE 402 will occur in a specific symbol. As further described below, this can be accomplished by sending the TA DCI in the common search space. Figure 12The gNB 170 can also inform all UEs in beam B1 about the parameters needed to demodulate the SRS signal from the reference UE 402, partially illustrated by 1204. This can be done using, for example, SIB signaling, as further described below.

[0067] Based on the information about the reference UE shared by the gNB 170 in the steps described above, the candidate UE 110 can use this information to demodulate the SRS from the reference UE 402 (see 1210). This is not difficult in a TDD deployment, since the candidate UE uses the same frequency on uplink and downlink. However, in the case of an FDD deployment, the candidate UE will have to demodulate the FDD uplink frequency. Thus, the proposed method naturally applies to TDD cells. However, it is also possible to implement the method in an FDD cell.

[0068] Reference Figure 5 At "(a)", the DL transmission at the gNB can be aligned with time t = 0. Due to the propagation delay, these transmissions are received at the reference UE 402 at time d / c (see "(b)" in Figure 5 Figure 5 The DL transmissions can be, for example, SSB signals transmitted by the gNB 170 at periodic intervals. The candidate UE 110 can record the time at which the SSB arrives at it as time "ti" in "(b)". Figure 5

[0069] Because the reference UE 402 is time-aligned with the gNB 170, the reference UE 402 transmits its SRS using a timing advance of (d + l) / c compared to the gNB time (t = 0) to ensure that the reference UE arrives at the gNB 170 at t = 0. Because the candidate UE 110 is located between the reference UE 402 and the gNB 170, this SRS signal arrives at the candidate UE 110 after l / c seconds. The candidate UE 110 records the time at which the SRS arrives at it as time "t2" (see "(e)" in Figure 5 The reference UE 402 can be time-aligned with the gNB to ensure that t1 and t2 are reliably measured and that the resulting TA estimated by the candidate UE 110 is accurately estimated. With the example method, the method does not actually measure the distance; only t1 and t2 are measured.

[0070] The candidate UE 110 can calculate its timing advance as TA = ti - t2 = 2d / c. Based on the distance between the candidate UE 110 and the gNB 170, this value is correct. The candidate UE 110 can also correctly estimate that the absolute time at the gNB before t1 starts (t1 - t2) / 2 seconds from t = 0. ​​

[0071] Figure 4 and 5 The examples shown in FIGS. 1-3 are merely to illustrate the basic idea of one proposed method. However, many non-ideal aspects can be considered and the basic idea can be extended to provide robust performance in real-world networks. Some of these aspects are considered in the examples below. The ability to utilize signals from a reference UE for more than one purpose makes the method clearly efficient. While regular TA estimation for UEs in idle mode uses regular 3GPP procedures and utilizes dedicated physical layer signals from the gNB specific to the candidate UE to estimate its TA, features as outlined herein can provide autonomous (or semi-autonomous) TA estimation that does not need to use regular 3GPP procedures with dedicated physical layer signals from the gNB, but can instead reuse (or assist with the reuse of) SRS signals transmitted by other UEs of the gNB that are assisted in being sensed / received by the candidate UE.

[0072] With features as outlined herein, valuable time-frequency resources that would have otherwise been used for TA estimation for individual UEs can instead be used for other purposes, such as user data. Furthermore, as outlined above, due to the signaling of the TA DCI by the gNB 170 in the common search space, multiple candidate UEs in the same beam can perform TA measurements based on a single SRS transmission from the same reference UE (or the same multiple reference UEs). In one example, compared to regular systems that use messages on the downlink and uplink for each UE and suffer from preamble collisions, with features described herein only the overhead due to the TA DCI and SIB signaling is needed. The SIB signaling is shown in part 1206 in FIG. 12. However, as outlined above, this overhead can be only a few bits, not for each candidate UE, and only on the downlink. Thus, in one example, these are the only changes that would need to be made in the 3GPP 6G standards to implement one example embodiment as outlined herein. Figure 12

[0073] While the SRS from the reference UE can be used to estimate the TA of the candidate UE 110, the proposed method should not be confused with a cooperation-based method (e.g., sidelink signaling). With features as outlined herein, there is no link or direct signaling between the reference UE 402 and the candidate UE 110. There is also no UE-specific signaling between the candidate UE 110 and the gNB 170. After receiving the SIB from the gNB, the candidate UE 110 is completely autonomous in estimating the TA based on the SRS signals sensed / received by other UEs and can remain in idle mode while estimating the TA. This is in contrast to cooperation-based methods that rely on sidelink / D2D signaling between the UEs that generate the overhead.

[0074] ​Impact of candidate UE and reference UE locations on accuracy of TA estimation

[0075] In Figure 4 , the gNB 170, the candidate UE 110, and the reference UE 402 are in a straight line with the candidate UE located between the gNB and the reference UE. This is an ideal topology where the estimated TA fully compensates for the propagation delay between the candidate UE and the gNB. However, in real-world networks, the UEs can not necessarily be geometrically positioned in this way. Aspects of this feature as outlined herein can be applicable to consider all possible positions of the candidate UE and the reference UE relative to each other and the gNB. The position of the reference UE relative to the candidate UE is an aspect that helps ensure accurate TA estimation. To illustrate the importance of this aspect, Figure 6 A scenario is shown where the potential reference UE 602 is located closer to the gNB 170 than the candidate UE 110. Similar to Figure 5 , Figure 7 A corresponding timing diagram is shown for the case illustrated in Figure 6

[0076] In this case, where the potential reference UE 602 is closer to the gNB than the candidate UE 110, t1-t2 = 2l / c is not correct to use as the timing advance. Since the correct TA for the candidate UE should be equal to 2(d+l) / c, the timing advance is highly underestimated. The position of absolute time t=0 is also estimated incorrectly, as the position of absolute time t=0 should be (t1-t2) / 2 seconds earlier than t1. This case, where the potential reference UE 602 is closer to the gNB than the candidate UE 110, is therefore not an acceptable case in which to use the UE 602 as the reference UE for the candidate UE. In this type of case, the candidate UE 110 should not select the UE 602 as the reference UE. Thus, with features as outlined herein, features can be provided to ensure that the candidate UE 110 correctly selects one or more reference UEs. In an example, the candidate UE 110 can ignore the TA measurement in Figure 6 topology in that the candidate UE 110 is capable of receiving beamforming and will know that the gNB and the reference UE are in the same receive beam or direction. In other words, the candidate UE 110 is capable of determining the receive beam from which it receives signals from both the gNB and the potential reference UE, and using this signal reception beam determination to determine whether the potential reference UE (e.g., 602 or 402) is closer to the gNB than the candidate UE. Ideally, from the candidate UE perspective, the gNB and the reference UE should be in the same receive beam as Figure 4 ​The shown full directions are opposite directions, but of course the ideal case will not always occur. Moreover, from an efficiency perspective, it is desirable that the maximum number of candidate UEs are able to perform reliable TA measurements based on SRS transmissions from the reference UE. From the above description, it can be observed that when the reference UE is located at the cell edge 404, the SRS of the reference UE can be used by the maximum number of candidate UEs to perform reliable TA measurements. Therefore, in one example, the gNB can be configured to select only those UEs that are located near the far cell edge as reference UEs. Identifying whether a reference UE is close to the cell edge is easy because the reference UE is in connected state or connected mode with the gNB, and thus the reference UE can send its TA to the gNB. Connected mode UEs that are time-aligned with the gNB and have TA values close to the values expected for a cell edge UE can be selected as reference UEs. For example, due to the narrow beam width in a beamformed cell as shown in Bl, such reference UEs will be almost ideally located in the candidate UEs in the beam (the candidate UEs are further inwards from the far cell edge 404 and closer to the cell center), and the estimated TA will be closer to the ideal correct value.

[0077] As above, in one type of example, the potential reference UEs can be located near the cell edge before being considered or selected by the candidate UE as reference UEs for TA estimation. However, another topology to consider is that the candidate UE is also located near the cell edge. Figure 8 A candidate UE 110 and two reference UEs 402 and 802 (also referred to as reference UE1 and reference UE2, respectively, below) are shown. Both reference UEs 402, UE 802 are located at the same distance l from the candidate UE 110. The candidate UE 110 can be configured to be a beamformed UE and configured such that the candidate UE 110 will only consider those TA measurements for potential reference UEs that are not located closer to the gNB than the candidate UE. In other words, the azimuth angle of the receive beam at the candidate UE when receiving from the reference UE is -90° < Θ < 90°. In Figure 8 In the shown case, the reference UE2 802 is located at Θ = 90°; at one of these extremes. The candidate UE 110 does not need to determine the exact angle Θ at which the reference UE is located. The candidate UE 110 can be configured to only ensure that the signal from the reference UE is received in a receive beam that is approximately opposite to the receive beam from which the gNB is received. This is shown in Figure 9The directions are generally shown with directional arrow 902 and generally opposite directional arrow 904. Arrow 902 shows signals from the gNB that can be received on a first side of the candidate UE, and arrow 904 shows signals from one or more reference UEs that can be received on an opposite second side of the candidate UE. For example, if the UE can form only two receive beams of 180 beamwidth, one receive beam will be directed toward the gNB and the other toward the reference UEs. In Figure 8 In the example of FIG. 8, candidate UE 110 and reference UE2 802 are located at the same distance from the gNB and thus are expected to have similar TA values. Reference UE1 402 is located farther from the gNB than the candidate UE and thus has a higher TA value. By preparing similar Figure 5 and Figure 7 In the example of FIG. 8, candidate UE 110 and reference UE2 802 are located at the same distance from the gNB and thus are expected to have similar TA values. Reference UE1 402 is located farther from the gNB than the candidate UE and thus has a higher TA value. By preparing similar Figure 8 and Figure 4 In the example of FIG. 8, candidate UE 110 and reference UE2 802 are located at the same distance from the gNB and thus are expected to have similar TA values. Reference UE1 402 is located farther from the gNB than the candidate UE and thus has a higher TA value. By preparing similar Figure 4 In the example of FIG. 8, candidate UE 110 and reference UE2 802 are located at the same distance from the gNB and thus are expected to have similar TA values. Reference UE1 402 is located farther from the gNB than the candidate UE and thus has a higher TA value. By preparing similar

[0078] When the distance between the potential reference UE and the candidate UE is not significant (e.g., 100-200 meters for a cell with a radius of 10 km), then the value of theta in the range -90° < theta < 90° can be considered unimportant. If the value of the distance / is significant (e.g., 1 km for a cell with a radius of 10 km), then the TA value is underestimated when theta > 0°, with the worst case theta = 90°; this is the case where the TA estimate is derived based on, for example, measurements from UE2 802. Based on a TA measurement with a single reference UE with theta close to 90° will likely introduce an error in the TA estimate for a candidate UE close to the cell edge. In one example embodiment, the candidate UE is best aware of the distance at which the reference UE is located; such as being able to determine if the TA estimate is good or not. However, the example method does not require the candidate UE to measure the distance to the reference UE. In an example embodiment, to ensure that the TA is not underestimated, the candidate UE can be configured to filter the TA measurements from multiple reference UEs, and prioritize measurements with theta closer to 0°. Thus, the gNB can configure multiple reference UEs in a gNB beam based on which candidate UEs can perform multiple TA measurements. As above, in practice, the candidate UE will not need to determine the exact value of theta. The candidate UE can be configured to prioritize the reference UEs located opposite to the receiving beam diameter from which the gNB’s receive beam is received. Examples of some mechanisms that enable the candidate UE to filter the measurements without knowing the exact value of theta are discussed below.

[0079] The candidate UE can use various criteria to filter the multiple TA measurements. As above, when estimating the TA, the SRS signals arriving from directions with theta closer to 0° can be given higher weight. Only in the case where the candidate UE can determine that the reference UE is close to it and thus the angle is not important, can the SRS signals from other directions be given higher weight. In an example implementation, to determine if the reference UE is close to it, the candidate UE can measure the received power of the SRS. As specified in 4G and 5G, and expected in 6G, the transmit power of the SRS is expected to be the same when the path loss (i.e., the distance from the gNB) is high. Based on the SSB power and the received RSRP, the candidate UE can measure the path loss from the gNB to its location, and determine the power Pc that would be needed if it were to transmit the SRS. In an example implementation, the candidate UE can be configured to prioritize the reference UEs with the lowest Pc. Figure 8In the middle, UE1 402 is further away from the gNB than the candidate UE and is positioned at an angle of theta that is closer to 0°, and thus will transmit SRS at a power that is greater than Pc. Thus, when received at the candidate UE, its SRS power will be close to Pc. UE2 802 will transmit SRS with a power that is almost equal to Pc. Thus, when received at the candidate UE, its SRS power will be much lower than Pc (except when it is located near the candidate UE). Based on the received power of the reference UE at the candidate UE, the candidate UE can determine which measurements can be considered valid and which measurements should be filtered out and not used for TA estimation. Furthermore, if the reference UE is able to transmit beamforming, it will transmit its beams to the gNB with relatively narrow beams, and thus, if theta is close to 0°, its SRS will be received only by the candidate UE, and if theta is close to 90°, it is not received by the candidate UE.

[0080] In one example, a criterion that can be used to filter TA measurements is the estimated TA value from each measurement. From earlier analysis, when theta is much higher than 0° and the reference UE is not close to the candidate UE, the TA measurement is lower. Thus, if the candidate UE has multiple TA measurements based on multiple reference UEs from more than one received beam in -90° < theta < 90°, the candidate UE can be configured to filter out measurements that are much lower than the other values; because these measurements are expected to be incorrect and from a direction where theta is close to 90°. A 6G UE is expected to have machine learning (ML) capabilities. Such a 6G candidate UE can use the measured TA, the measured power, and the receiver beam of the received SRS signal, or a combination of all three, to filter the TA measurements. Based on these multiple criteria and TA measurements from multiple reference UEs, such a UE can filter the measurements and derive a TA estimate that is close to the correct value. Based on the distribution of filtered measurements, the UE can also determine whether the quality of the estimate is good.

[0081] In the example in Figure 8 In the example in, the candidate UE 110 is further away from the edge of the beam produced by the gNB, and thus can prioritize TA measurements where theta is closer to 0°. A UE that is located near the edge of two beams produced by a gNB can be configured to prioritize measurements that are offset from 0° by a small amount. The UE can be configured to determine whether it is located at the edge of two gNB beams by measuring the RSRP level of each beam. In effect, the candidate UE can prioritize the receive beams that are opposite to the gNB.

[0082] It is important to note that there is no correspondence between the candidate UE and the reference UE. The candidate UE can perform multiple TA measurements corresponding to multiple reference UEs. Multiple candidate UEs can perform TA measurements based on SRS signals transmitted by a single reference UE. Therefore, multiple candidate UEs can estimate their TA based on SRS signals transmitted by multiple reference UEs.

[0083] Impact of expected error in TA estimation and preamble design

[0084] Similar to 5G cells, 6G cells are expected to have narrow beams. Because the reference UE is located near the cell edge, from Figure 4 It can be observed that for candidate UEs that are far from the cell edge, the filtered TA measurements will have a low-variance distribution and the TA estimate will be close to the correct value, regardless of the reference UE they use, as θ will always be within a few degrees of 0°. From Figure 8 It can be seen that for candidate UEs located near the cell edge, for a cell with beam width of Φ radians and cell radius of R, in the worst case when θ = 90°, l is equal to ΦR and the TA measurement error it introduces is ΦR / c. Because multiple TA measurements are recommended to be used, this worst-case measurement can be filtered out. However, this calculation can be used to determine the worst-case maximum error in the TA estimate. Therefore, if a candidate UE is to estimate its TA based on such a TA measurement, it will underestimate the TA by ΦR / c. As an example, considering a beam width of 30° (Φ = Π / 6), the estimation error will be ~ R / 2c. This is only 25% of the round-trip time (2R / c) used as the propagation distance factor in the preamble design. Therefore, even in the worst case and with a fairly high beam width, using the proposed method, the gNB can use a preamble format where CP, GP, and N CS can be reduced by 75%. Moreover, using reference UEs from neighboring beams will introduce too much error in the TA measurements for candidate UEs located near or far from the cell edge. Based on this discussion, although this method performs best in beamformed cells, non-beamformed cells (where the candidate UEs can autonomously detect the direction of the reference UEs) can also use the proposed TA estimation method. Such UEs in non-beamformed cells can use the TA estimate, for example, only when they can determine that θ is close to 0°.

[0085] Therefore, this method can provide reliable TA estimation when the candidate UE is located far from the cell edge. For such candidate UEs, the measurements based on two or three reference UEs can provide good TA estimation as the variance in the measurements will be smaller. The candidate UEs located in this way can use the TA measurements from multiple reference UEs to verify that the estimated TA is indeed correct. When the candidate UE is located closer to the cell edge, the TA measurements corresponding to multiple reference UEs can have higher variance, but the error in the TA estimation can be limited. The preamble design using this worst-case error in the TA estimation can still provide CP, GP, and N CS values that are 75% smaller in size. Typically, this method performs better when the beams are loaded (i.e., the number of reference UEs increases) as it allows the UE to obtain multiple measurements of 0 closer to 0°, ultimately helping the UE to converge to the TA estimation with minimal error.

[0086] Because the proposed method allows the idle-mode UE to estimate its TA, one application of the estimated TA is to allow the UE to pre-compensate the propagation delay (PD) while transmitting the preamble, and thus allow the gNB to use the preamble format with smaller CP, GP, and N CS values. Here, pre-compensation means that the UE transmits the preamble after advancing the uplink transmission by the TA value it has estimated. Based on the maximum error expected in the autonomously estimated TA, a preamble design with appropriate values of CP, GP, and N CS can be selected. Some of the available PRACH occasions can also be reserved for the preamble format, where CP, GP, and N CS values correspond to twice the cell radius, so that the 6G UE can fall back to using the traditional TA estimation method. These can be used in situations where there are not enough reference UEs available, and thus, the 6G UE cannot reliably estimate its TA using the existing reference UEs. In one example, the 6G gNB can thus have two or more types of PRACH occasions supporting at least two types of preamble formats, such as: the preamble format with smaller CP, GP, and N CS for candidate UEs that can reliably estimate their TA, and the preamble format with larger CP, GP, and N CS (corresponding to twice the cell radius) for candidate UEs that cannot reliably estimate their TA. The gNB can also control the use of the proposed method to ensure that the UE uses the PRACH occasions with smaller CP, GP, and N CS values only when a minimum number of reliable TA measurements are available after filtering or the candidate UE is located far from the cell edge. This is discussed further below.

[0087] Aspects of SRS scheduling for reference UEs

[0088] The quality of the TA estimate can depend on the time when it is estimated and the time when it is used. This can depend on the mobility of the candidate UE. With reference to Figure 5 , the time t1 depends on the reception time of the SSB. If the candidate UE knows that it is moving, it can compute the value of t1 from the latest SSB burst set received before the PRACH occasion in which the candidate UE will send its preamble. To ensure that the time t2 is accurate, the gNB can try to schedule the SRS for the reference UEs in the slot before the PRACH occasion of the preambles with smaller CP, GP and N CS . This will ensure that the TA value computed for a moving candidate UE has not changed significantly before the candidate UE sends its PRACH.

[0089] The filtering of the TA measurements at the candidate UE can take into account the mobility of the UE itself. If it knows that it is moving, the old TA measurements can not be given a high weight in the final estimate. As before, a machine learning (ML) process based on the TA measurements, the candidate UE can determine the quality of its TA estimate. If the quality is not good and the filtered TA estimate has a high variance, the candidate UE can use the PRACH occasions with preambles having larger CP, GP and N CS . As discussed further below, if a reliable TA estimate cannot be guaranteed, the gNB can also control the TA measurements of the candidate UEs and prohibit the use of the PRACH occasions with preambles having smaller CP, GP and N CS .

[0090] The TA of the reference UEs can fully compensate for the propagation delay of their signals to the gNB. Therefore, the TA for the reference UEs is best updated by the gNB before they send their SRS. However, this can not be necessary for stationary reference UEs. Therefore, the UEs selected as reference UEs are best stationary or slowly moving to ensure that the TA measurements are robust. In an example embodiment, from this perspective, FWA (fixed wireless access) UEs located near the cell edge can be ideal reference UEs.

[0091] The gNB does not always request the UEs to perform SRS transmission for link adaptation. For UEs transmitting at full rank in the uplink, DMRS can be used to perform link adaptation. In this case, the candidate UEs can not be able to perform TA measurements due to the lack of SRS transmission from the reference UEs. However, this is less likely to happen because of the way the reference UEs are selected in the proposed method. Because the reference UEs are located near the cell edge, it is likely that their transmission rank is not full rank. Therefore, SRS transmission is likely to be requested from the reference UEs.

[0092] Another aspect that can be considered is the time alignment of the accumulated uplink transmissions at the candidate UE from the UEs scheduled together with the reference UE. The transmissions from the UEs within the cell are time aligned with respect to the gNB, i.e., to ensure that these transmissions are received at the gNB within a cyclic prefix (CP) time window. When the SRS of the reference UE is received at the candidate UE, the transmissions from the UEs scheduled in the same symbol as the SRS can not be received within the CP time window, as they have not been transmitted together with this consideration. Furthermore, the transmissions from the UEs in the symbol adjacent to the SRS of the reference UE can spill over the symbol boundary and interfere with the SRS reception when received at the candidate UE. This can make the proposed method unusable due to excessive ISI and ICI from the transmissions in the same and adjacent symbols. However, this can be easily avoided by scheduling the UEs from other beams in the same symbol adjacent to the reference UE and in multiple same symbols. The candidate UE will not receive these signals in its receiver beam, as the receiver beam of the candidate UE is directed towards the reference UE. Thus, the SRS signal of the reference UE received at the candidate UE will not be corrupted by ISI and ICI. For example, as shown in Figure 10 FIG. 1, when scheduling the SRS of the reference UE, uplink transmissions from the UEs in beam B3 can be scheduled in the adjacent symbol. The uplink transmissions from the UEs in beam B3 will be transmitted towards the gNB. Because the receive beam of the candidate UE in beam Bl is directed towards the reference UE, the uplink transmissions from the UEs in beam B3 will not be received at the candidate UE and will not corrupt the reception of the reference UE with ICI and ISI. Even if the signals from the UEs in beam B3 find their way to the receive beam of the candidate UE due to multipath reflections, the power of this interfering signal will be too low to significantly affect the SNR of the demodulated SRS signal. In an exemplary embodiment, the reference UE can be scheduled in the first uplink symbol after a gap period in a special slot. A special slot is a slot containing downlink symbols, followed by a gap period, and then uplink symbols. In such an embodiment, the scheduling considerations described above can only have to be satisfied for the SRS of the reference UE and the subsequent symbol. Figure 10 The illustration in FIG. 1 also shows that, in terms of reducing the ICI and ISI impact from the UEs scheduled together with the reference UE, it is beneficial to prioritize the TA measurement from the reference UE that is closer to 0° than.

[0093] If the transmit beam of the UE in gNB beam B3 is not a narrow beam and its signal is expected to interfere with the receive beam of the candidate UE in gNB beam B1, the gNB can alternatively schedule the UE in a gNB beam that is orthogonal or in a completely opposite gNB beam to gNB beam B1. This will ensure that the candidate UE can reliably receive the reference UE. Thus, despite having good capabilities, the UE is not forced to support transmit beamforming when using the proposed method.

[0094] Gnb control of TA measurement

[0095] As outlined above, the preamble design with smaller CP, GP and N CS values is selected based on the maximum expected error in the autonomous estimation of the TA for candidate UEs located near the cell edge. For additional reliability, the gNB can use CP, GP and N CS values corresponding to the maximum expected error, but it is expected that the use of the proposed method is limited to candidate UEs located far from the cell edge. To this end, in an exemplary implementation, the gNB can signal a threshold RSRP TA to the UE. Only when the measured SS-RSRP (or equivalent measurement quantity in 6G) is greater than RSRP TA , the candidate 6G UE can use the proposed method to perform the TA measurement. The 6G gNB can derive the value of RSRP TA by averaging the SS-RSRP values sent by the reference UE and then adding an offset that determines the range within which the gNB allows the candidate UE to use the proposed method. A lower offset allows the proposed method to be used by candidate UEs closer to the cell edge, and vice versa for a higher offset. Because the reference UE is in connected mode, the layer 1 SS-RSRP values from the reference UE can be easily obtained at the gNB from the CSI report sent for beam management by connected mode UEs (as in 5G). In addition, the cell edge reference UE can also be configured to send a layer 3 measurement report including layer 3 SS-RSRP values. If the measured SS-RSRP at the candidate UE is lower than RSRP TA , the candidate UE can determine that it is located closer to the cell edge and thus can not be allowed to autonomously estimate its TA using the proposed method. The candidate UE will not use the proposed method to perform the TA measurement, but instead use a PRACH occasion with CP, GP and N CS values corresponding to twice the cell radius. The gNB can also signal the number N RefUeTA。 if the candidate UE is not able to perform N RefUeTATA measurement, it can be assumed that a reliable autonomous TA estimation is not possible and it can fall back to using PRACH occasions whose CP, GP and NCS values correspond to twice the cell radius. The gNB can signal the RSRP threshold via SIB message TA and N RefUeTA .

[0096] For candidate UEs capable of speed estimation, the gNB can similarly signal a speed threshold via SIB message. This can be used to limit high speed UEs from using unreliable TA estimation and causing interference. Candidate UEs travelling above the threshold speed can use PRACH occasions whose CP, GP and N CS values correspond to twice the cell radius.

[0097] Time dispersion

[0098] The impact of time dispersion of SSBs transmitted by the gNB and SRS transmitted by the reference UE is not shown in the figure. However, the impact can be similar to the way in 3GPP, i.e. due to delay spread, multipath introduces few microseconds of bias in the computed TA. The impact of delay spread can actually be lower when using this method. The reference Figure 5 Due to the time dispersion between the gNB and the candidate UE, ti can be increased. But t2 can also be increased due to the time dispersion between the reference UE and the candidate UE. Thus, the proposed method can reduce the impact of time dispersion on the estimated TA value compared to the traditional method in 3GPP.

[0099] Another embodiment related timing aspect is that the ti and t2 measurements in Figure 5 may not always correspond to the same OFDM slot or symbol. Specifically, t2 can only be measured when the gNB needs to receive link adaptation SRS from the reference UE. However, the candidate UE can be aware of the slot length and OFDM symbol length. Thus, if ti and t2 are measured in different slots and / or symbols, the timing can be normalized by subtracting the time equal to the number of slots and / or symbols between ti and t2.

[0100] Light load beams

[0101] In light loaded beams, the number of expected reference UEs is less and for some candidate UEs it can not be possible to perform enough measurements to obtain a reliable TA estimation using the proposed method. However, the motivation to save time-frequency resources is also much less in lighter loads. Thus, in lighter loads, preambles with large (corresponding to twice the cell radius) CP, GP and N CS values can be used more often by candidate UEs. With smaller CP, GP and N CSThe number of such PRACH occasions can be higher compared to the PRACH occasions with CP, GP and N CS of two times the cell size. When the beams are highly loaded, multiple reference UEs and hence TA measurements are available, increasing the feasibility of the proposed method. The motivation for reducing the usage of time-frequency resources for TA estimation and instead using these resources for user data is also higher. Hence, in this case, candidate UEs can use the proposed TA estimation method more frequently. With CP, GP and N CS of two times the cell size, the number of PRACH occasions can be higher compared to the PRACH occasions with smaller CP, GP and N CS . Hence, the proposed method is unique as it saves more time-frequency resources and reduces the signaling load in high load scenarios. The conventional method in 3GPP would instead suffer from throughput degradation as the load of TA estimation increases with the number of UEs.

[0102] TA estimation for reference UEs

[0103] In the above example method, it has been assumed that the reference UEs are already aligned with the gNB. When these UEs are located far from the cell edge, some of these UEs can have been TA aligned in the idle state using the proposed method and would have moved to the connected mode by using PRACH occasions with smaller CP, GP and N CS . Then, continuous TA alignment for such UEs can be performed in the connected mode. When such UEs move closer to the cell edge, they can be used by the gNB as reference UEs. In an example embodiment, FWA (Fixed Wireless Access) UEs at the cell edge can be used as reference UEs. Such UEs would be permanently aligned with the gNB. In other cases, candidate 6G UEs at the cell edge can be TA aligned using PRACH occasions with CP, GP and N CS of two times the cell size and then used as reference UEs.

[0104] Use cases, advantages, and comparison to prior art

[0105] Traditionally, in each generation, even in 5G, UE-specific signals are used for procedures specific to that UE. With the example method as outlined herein, the method can enable paradigm shift in 6G gNBs, where UE-specific signals specific to a UE (in this case, SRS) can be processed to derive useful information for other UEs. Thus, the overall signaling load is reduced, ultimately improving cell throughput. gNBs can transmit beamformed signals in 5G, but because receiving beamforming UEs are not common in 5G, the proposed method can not work reliably in 5G. Due to the receiving beamforming capability of 6G UEs, the proposed method will work reliably in 6G and produce the applications and advantages pointed out below.

[0106] An adaptive control of the combination of preamble formats can be provided, e.g., with a 6G gNB. A lightly loaded gNB can know that the number of reference UEs is less than the required number, and some candidate UEs can not be able to perform enough measurements to estimate TA using the proposed method. Thus, the gNB can configure more PRACH occasions of preamble formats with higher CP, GP, and N CS values (corresponding to twice the cell size). As the load increases and enough reference UEs become available for most candidate UEs, it can reduce the number of PRACH occasions of preamble formats with higher CP, GP, and N CS and increase the number of PRACH occasions of preamble formats with lower CP, GP, and N CS . Additionally, for occasions with lower CP, GP, and N CS , the gNB can adapt the CP, GP, and N CS values based on the expected error in the TA estimation. Thus, a RACH design for 6G gNBs can be created that adapts the preamble format in conjunction with the cell load. Because more candidate UEs can derive reliable TA estimates using the proposed method when beams become heavily loaded, more PRACH occasions with lower CP and GP values can be used, freeing up the time-frequency resources used by larger CP and GP. These resources can then be used to improve cell throughput or increase more PRACH occasions. If the total number of PRACH occasions remains the same as the load increases, the method can show a parity advantage, where the time-frequency resource usage for PRACH decreases, rather than increases, as the number of UEs increases.

[0107] Idle mode UE positioning can be provided. By computing TA using the proposed method and knowing the beam, an idle mode UE can estimate its approximate location in an isolated cell. In a cell that is not isolated, the method is useful for UEs positioned far from the cell edge, as they can not receive signals from multiple gNBs to perform OTDOA position estimation. Reconfigurable intelligent surfaces (RIS) have been proposed for 6G UEs located near the cell center for UE positioning. However, unlike RIS, the proposed method can be used to position idle mode UEs and does not require RIS.

[0108] A candidate UE can measure TA based on multiple reference UEs, filter the measurements, and based on the distribution of the filtered measurements, it can determine whether the quality of the TA estimate is good. A UE knowing that the quality of the TA estimate is not good can use PRACH occasions with higher CP, GP, and N CS values corresponding to twice the cell size. The gNB can also use RSRP TA and N RefUeTA explicitly control the quality of the estimate. Thus, the method is robust.

[0109] 2-step RACH can require a guard period of several symbols to combat ISI due to propagation delay. The guard period can correspond to twice the cell radius. A UE using the proposed method can compensate for the propagation delay and thus can use the guard period to only account for the expected TA estimation error. Thus, in the case of 2-step RACH, the proposed method reduces the waste of valuable PUSCH resources. As above, for a beam with a 30° beamwidth, GP can be reduced by over 75%.

[0110] Signaling-based TA estimation methods can only provide TA after the signaling required to complete the TA estimation. Because PUSCH data can only be sent after the TA is compensated, these methods suffer from high latency. Using the proposed method, a UE can start transmitting directly on the PUSCH, as in 2-step RACH, resulting in lower latency.

[0111] By pre-compensating PD before preamble transmission, the number of preamble resources can be increased, e.g., by reducing N CS . Thus, preamble planning can also become simpler.

[0112] Reduced CP and GP enable energy-efficient RACH signal design. UE power is not wasted on redundant time-frequency resources.

[0113] Regarding security, UE-specific signals are demodulated by other UEs, but this is not a problem because SRS is only a physical layer signal and does not contain any user data.

[0114] While the description of the proposed method uses aperiodic SRS, the method does not exclude the use of other transmissions from the reference UE, including but not limited to periodic SRS and DMRS associated with PUCCH / PUSCH transmissions. All these transmissions are sent by the reference UE with timing advance and can be used to estimate the TA of the candidate UE. In particular, the DMRS signal provides an advantage because the symbols adjacent to the DMRS come from the same user and, therefore, the scheduler is not constrained in time domain to schedule the UE together with the reference UE, as Figure 10 indicated in

[0115] While the method is particularly useful for idle mode UEs, connected mode UEs can also autonomously adjust their TA if the TA estimation quality is good and error-free. This is particularly relevant for candidate UEs located close to the cell center. Therefore, the connected mode time alignment timer in 6G, corresponding to the timeAlignmentTimer in 5G, can be set to a higher value and the signaling dedicated to timing alignment can be reduced. The 6G gNB can set the time alignment timer for connected mode candidate UEs to a higher value in loaded beams because the candidate UEs can autonomously generate robust TA estimates under such conditions. Therefore, for connected mode UEs, the proposed method can help reduce the signaling overhead under loaded conditions. Similarly, the common time alignment timer in 6G, corresponding to timeAlignmentTimerCommon in SIB1 in 5G, can be set to a higher value in loaded beams.

[0116] In US2022 / 0217669A1, TA adjustment is described to be performed autonomously by the UE based on RSRP and UE position and results in signaling overhead. US2019 / 0159149A1 describes estimating the TA using RSRP and satellite positioning. In contrast, the UE using the proposed method also performs the TA estimation autonomously; however, the proposed method has minimal signaling overhead and it is more predictable because the TA is measured directly from timing measurements, not derived from RSRP. Moreover, satellite positioning can not always be available.

[0117] In US2021 / 0297976A1, a single cell range based technique is used and the UL transmission is performed multiple times if the predicted TA value happens to be incorrect, which results in signaling overhead. In contrast, the current proposal explicitly produces a TA estimation method that reuses existing signals sent by other UEs. Because multiple UEs and, therefore, data points are available, the current proposal is more robust compared to US2021 / 0297976A1. Moreover, the quality of the estimation and, therefore, the robustness can be controlled by the gNB.

[0118] Unlike some solutions in the prior art, the proposed method does not require multiple cells, multiple cell-specific overheads, and cooperative communication between cells. In fact, the proposed method can also work in a single isolated cell.

[0119] Some solutions in the prior art are only for stationary candidate UEs. In contrast, the proposed method is generic and suitable for mobile candidate UEs. Such solutions require random access signaling for initial TA computation, after which TA adjustment can be performed. However, the proposed method can perform TA adjustment for UEs that have not performed random access on the network.

[0120] Unlike some solutions in the prior art, a UE using the proposed method does not need to perform complex processing of RSRP values. Moreover, because direct TA measurement using the proposed method is available, the estimation is robust compared to RSRP value-based processing. Therefore, the design of CP, GP, and N CS can be deterministic because the maximum error of a single measurement is limited in the proposed method, as outlined above. Moreover, the gNB can control and ensure the reliability of the estimation by using the parameters RSRPI TA and N RefUeTA Unlike solutions in the prior art, the proposed method does not require training data.

[0121] In contrast to passive techniques, the proposed method does not require preamble transmission (i.e., signaling) or the use of passive receiving devices with known locations to estimate TA. Existing UEs can be used as reference UEs and do not require additional hardware. The proposed method also does not require knowledge of the exact location of the reference UEs.

[0122] In contrast to cooperative methods, the proposed method does not require additional hardware or UE support for sidelink / D2D communication.

[0123] In one example, while the proposed concept has many advantages, there are no side effects because if a candidate UE is not able to reliably estimate its TA using the proposed method, it can fall back to using PRACH occasions with CP, GP, and N CS values corresponding to twice the cell size.

[0124] As outlined above, in terms of standardization, the proposed method can only add a few bits to SIB and DCI signaling.

[0125] Standardization aspects

[0126] The proposed method can be implemented in 6G by including the following signaling components: • To demodulate the SRS transmitted by the reference UEs, the candidate UEs should know its parameters. These parameters in the 6G gNB would correspond to the 5G parameters within the SRS resource IE in TS 38.331. These parameters can be defined within the SIB message in 6G. If necessary, this SIB message can also signal the RSRP TA and N RefUeTA values. The gNB can use the parameters signaled in the SIB message to configure the reference UEs to transmit their link adaptation SRS. All the reference UEs can use this common set of parameters to transmit their link adaptation SRS; Although at different times. • The timing advance DCI can be used to inform the UEs in the base station beam that the SRS transmission will occur from the reference UEs that can be used for TA measurement. The PDCCH is beamformed, so only the UEs within the same base station beam will be informed of the SRS transmission from the reference UEs. The TA DCI can be transmitted in the common search space. Because the parameters defining the SRS are set in the SIB message, the TA DCI can be used only to inform the UEs about the beam for the upcoming SRS transmission and, thus, consume a minimum number of bits.

[0127] The proposed method can define the parameters of the SRS resource in the SIB message and use the TA DCI containing a minimum number of bits to signal the transmission of the SRS. In return, tens of candidate UEs in the beam can be able to perform the TA estimation autonomously. The signaling load for the TA estimation can not increase proportionally with the number of UEs. Figure 11 An exemplary 6G signaling flow for TA estimation using the proposed method is shown. The steps in this example MSC (message sequence chart) are: 1. The gNB signals the parameters defining the SRS of the reference UEs via the SIB. If necessary, the same SIB message can also be used to transmit the RSRP TA and N RefUeTA . 2. To ensure that the designated reference UEs use the parameters signaled in the SIB message to transmit their SRS, every time the gNB identifies a new reference UE, it should configure one of the reference UEs' SRS signals with the parameters signaled in the SIB message. The use / purpose of the SRS will remain codebook-based link adaptation; only the SRS attributes (e.g., time-frequency resources, hopping, etc.) will be similar to the parameters signaled in the SIB message. As in 5G, the SRS configuration for the reference UEs is expected to be a standard 6G Part of the call flow. The only change in the proposed method is that the SRS parameters will be set according to those defined in the SIB message. 3. The reference UE in connected mode is sent DCI for uplink or downlink transmission with SRS request bit set appropriately to request the reference UE to transmit the link adaptation SRS configured in step 2 above. As in 5G, this is expected to be part of the standard 6G call flow and the proposed method does not change it in any way. 4. While the DCI for uplink or downlink transmission containing the SRS request bit is sent to the reference UE, the gNB sends a TA DCI in the common search space to inform all the UEs within the beam that the reference UE will transmit SRS which they can use to perform TA measurement. Subsequently, the reference UE performs SRS transmission and the candidate UEs can perform TA measurement in accordance with Figure 5 the timing diagram in FIG. 1.

[0128] The physical layer signal of the reference UE, e.g., SRS, can be used to autonomously measure the TA of one or more candidate UEs. The candidate UEs can estimate their TA based on measurements from more than one reference UE. The candidate UEs can perform TA estimation in idle mode.

[0129] The parameters of the SRS can be broadcast to the UEs within the beam using broadcast signaling, such as SIB signaling. The candidate UEs in the beam can be informed from the reference UE using broadcast signaling, e.g., the TA DCI sent in the common search space. The reference UEs are configured with the SRS parameters using point-to-point RRC reconfiguration message. The candidate UEs use the broadcast information.

[0130] The reference UEs can be UEs located at or close to the cell edge. The reference UEs can be time advanced so that they are time aligned with the gNB.

[0131] The candidate UEs can be capable of receiving beamforming with a minimum requirement of two (2) receive beams. The proposed method does not need to know the exact angle from which the candidate UEs receive signals.

[0132] The transmission scheduled in the same symbol as the SRS of the reference UE and the symbol adjacent to the SRS can be from a UE that is far away (i.e., not adjacent) from the gNB beam in which the reference UE is located.

[0133] The proposed method can have a bounded estimation error. The gNB can tailor the preamble design according to the maximum expected TA estimation error. With the example method, the bounded estimation error is not sent to the candidate UEs. Additionally, the handover can be based on RSRP TA and N RefUeTAAs an input from the network equipment to the device. The first timing advance mode can use PRACH preambles with shorter cyclic prefix, guard time and Ncs. The length of these parameters depends on the maximum value of the estimation error. In practice, the estimation error will be responsible by the shorter cyclic prefix, guard time and Ncs. Therefore, making the value of these parameters based on a bounded estimation error will ensure that the proposed method works in a robust way.

[0134] As mentioned above, the example method does not determine the position. RSRP TA Can be used as a parameter to decide whether a candidate UE is near the cell edge or near the cell center. This parameter can be used as an input for handover and the example method does not actually compute the distance.

[0135] The proposed method can perform better when the reference UE is fixed or a FWA UE. A FWA UE can be used as an ideal reference UE.

[0136] The main content of the SIB is the SRS parameters (parameters containing at least the time and frequency position of the SRS). RSRP TA And N RefUeTA Are other parameters that can be used to control the robustness of the method. The gNB can control the maximum TA estimation error and, therefore, the robustness of the method using the parameters RSRP TA And N RefUeTA . The gNB can limit the use of the proposed method for TA estimation for high speed candidate UEs.

[0137] The gNB can have two types of PRACH occasions using two different preamble formats: one preamble format with higher CP, GP and N CS And a second preamble format with lower CP, GP and N CS . The gNB can adapt the number of PRACH occasions according to the UE load in the beam.

[0138] The features described herein can be used to provide a mechanism to estimate timing advance for a UE in idle mode for 6G. The RAN can select a connected mode UE in a beam that is time-aligned with the RAN and located near a cell edge; the UE can be referred to as a reference UE. The RAN can send symbol information in a TA (timing advance) DCI in a common search space to a candidate UE to monitor for SRS (sounding reference signal) transmissions in that symbol, and inform the UE via SIB signaling about the parameters required to demodulate the SRS signal. When the reference UE transmits an SRS to the RAN, the candidate UE can demodulate the SRS from the reference UE based on information received from the RAN about the reference UE. The candidate UE can then autonomously estimate the TA based on the demodulated SRS signal. Thus, the feature can provide a method for autonomous timing advance (TA) estimation for idle mode UEs by reusing the SRS signal sent by a connected mode UE in a cell edge for the candidate UE to estimate the TA of the candidate UE in idle mode (such as, for example, 6G).

[0139] There can be one or more reference UEs. DL transmissions can be SSB. Candidate UEs are capable of receiving beamforming with a minimum requirement of two (2) receive beams. Candidate UEs can autonomously estimate TA in the following steps: • The RAN performs DL transmissions aligned with time t=0, and these transmissions are received at the candidate UEs and at the reference UE with a propagation delay. The candidate UE records the arrival time of the DL signal and the SRS, and calculates its timing advance as the time difference between the two. The candidate UE can also correctly estimate that the absolute time t = 0 at the RAN begins (t1 - t2) / 2 seconds before t1. Transmissions scheduled in the same symbol as the reference UE and adjacent to the SRS symbol are from UEs in RAN beams that are not adjacent to the RAN beam in which the reference UE resides. The gNB performs scheduling. The reference UE can be a stationary or FWA (Fixed Wireless Access) UE. The gNB can select whether the reference UE is stationary or FWA. The RAN can adapt the number of PRACH opportunities based on the UE load in the beam.

[0140] The feature can be used to reduce the overall signaling load. The feature can be used to improve cell throughput. The feature can be used to provide adaptive control of preamble format combinations in 6G gNBs and above. The feature can be used to provide idle mode UEs with an ability to estimate their approximate position in isolated cells. The feature can be used to provide a robust estimation process compared to RSRP-based estimation. The feature can be used to provide a method that does not require additional hardware or UE support, such as for sidelink / D2D communications.

[0141] According to one example embodiment, an apparatus is provided comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: determining information about a physical layer signal to be transmitted from a user equipment; receiving, by the apparatus, the physical layer signal transmitted from the user equipment; and determining, by the apparatus, a timing advance for the apparatus to use for transmitting a signal to network equipment based on the determined information and the reception of the physical layer signal.

[0142] The receiving of the physical layer signal can occur without transmitting to the network equipment in the uplink. The instructions, when executed by the at least one processor, can cause the apparatus to perform receiving symbol information from the network equipment, where the symbol information is configured to be used with the apparatus for demodulating the physical layer signal received from the user equipment. The symbol information can include downlink control information in a common search space from the network equipment. The symbol information can include information about the physical layer signal to be transmitted from the user equipment. The symbol information can include a system information block. The physical layer signal can include a sounding reference signal transmitted from user equipment. The determining the information about the physical layer signal to be transmitted from the user equipment includes use of parameters configured to decode the physical layer signal, where the parameters indicate at least a location of the physical layer signal in a time domain and a frequency domain. The determining the information about the physical layer signal to be transmitted from the user equipment can include receiving broadcast signaling from the network equipment, where the broadcast signaling includes information configured for the apparatus to decode a sounding reference signal transmitted from the user equipment. The broadcast signaling can include at least one of a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate a timing advance of the apparatus. Where the determining the information about the physical layer signal to be transmitted from the user equipment includes receiving timing advance downlink control information from the network equipment, where the timing advance downlink control information is configured to inform the apparatus in a base station beam of the network equipment that a sounding reference signal transmission will be made from the user equipment that can be used for timing advance measurements. The apparatus can be in an idle mode. The determining the information includes receiving symbol information from the network equipment, and where the instructions, when executed by the at least one processor, cause the apparatus to perform switching between a first timing advance mode and a different timing advance mode based at least in part on the symbol information received from the network equipment and the physical layer signal received from the user equipment. The receiving of the physical layer signal includes receiving physical layer signals from a plurality of user equipment, and where the instructions, when executed by the at least one processor, cause the apparatus to perform selecting, based on parameters received by the apparatus from the network equipment, the physical layer signal to be used for the determining the timing advance from the one or more of the plurality of user equipment. The receiving of the physical layer signal includes receiving physical layer signals from a plurality of user equipment, and the determining the timing advance can include determining respective timing advance measurements for the plurality of user equipment, and determining the timing advance based on parameters received by the apparatus from the network equipment and based on the determined timing advance measurements.The determination of the timing advance: without explicit or implicit knowledge of the location of the apparatus, without use of network equipment, without establishing a link with the user equipment, without receiving timing advance information from the user equipment, and without using stored timing advance as the timing advance.

[0143] Reference is also made to Figure 13According to one example embodiment, an example method can be provided including determining, by an apparatus, information about a physical layer signal to be transmitted from a user equipment, as shown in block 1302; receiving, by the apparatus, the physical layer signal transmitted from the user equipment, as shown in block 1304; and determining, by the apparatus, a timing advance for the apparatus to use for transmitting signals to network equipment based on the determined information and the reception of the physical layer signal, as shown in block 1306. The reception of the physical layer signal can occur without transmitting to the network equipment in an uplink. The method can include receiving symbol information from the network equipment, where the symbol information is configured to be used with the apparatus for demodulating the physical layer signal received from the user equipment. The symbol information can include downlink control information in a common search space from the network equipment. The symbol information can include information about the physical layer signal to be transmitted from the user equipment. The symbol information can include a system information block. The physical layer signal can include a sounding reference signal transmitted from user equipment. The determining the information about the physical layer signal to be transmitted from the user equipment includes use of a parameter configured to decode the physical layer signal, where the parameter indicates at least a location of the physical layer signal in a time domain and a frequency domain. The determining the information about the physical layer signal to be transmitted from the user equipment includes receiving broadcast signaling from the network equipment, where the broadcast signaling includes information configured for the apparatus to decode a sounding reference signal transmitted from the user equipment. The broadcast signaling can include at least one of a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate its timing advance. The determining the information about the physical layer signal to be transmitted from the user equipment can include receiving timing advance downlink control information from the network equipment, where the timing advance downlink control information is configured to inform the apparatus in a base station beam of the network equipment that a sounding reference signal transmission will be made from the user equipment that can be used for timing advance measurements. The apparatus can be in an idle mode. The determining of information can include receiving symbol information from network equipment, and further including switching between a first timing advance mode and a different timing advance mode based at least in part on the symbol information received from the network equipment and the physical layer signal received from the user equipment. The receiving of a physical layer signal can include receiving physical layer signals from a plurality of user equipment, and further including selecting, based on a parameter received by the apparatus from the network equipment, the physical layer signal to be used from the one or more of the plurality of user equipment for the determining of the timing advance.The reception of the physical layer signal can include reception of the physical layer signal from a plurality of user equipment, and the determination of the timing advance can include determining respective timing advance measurements for the plurality of user equipment, and determining the timing advance based on parameters received by the apparatus from the network equipment and based on the determined timing advance measurements. The determination of the timing advance can be without explicit or implicit knowledge of a location of the apparatus, without use of a plurality of network equipment, without establishing a link with the user equipment, without receiving timing advance information from the user equipment, and without use of a stored timing advance as the timing advance.

[0144] According to one example embodiment, an apparatus comprises means for determining information about a physical layer signal to be transmitted from a user equipment; means for receiving the physical layer signal transmitted from the user equipment; and means for determining, by the apparatus, a timing advance for the apparatus for transmitting a signal to a network equipment based on the determined information and the reception of the physical layer signal.

[0145] According to one example embodiment, a program storage device can be provided by an apparatus tangibly embodying a program of instructions executable by the apparatus to perform operations comprising determining information about a physical layer signal to be transmitted from a user equipment; receiving the physical layer signal transmitted from the user equipment; and determining, by the apparatus, a timing advance for the apparatus for transmitting a signal to a network equipment based on the determined information and the reception of the physical layer signal.

[0146] According to one example embodiment, an apparatus is provided comprising at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform determining information related to a physical layer signal to be received by the apparatus, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus; and transmitting, by the apparatus, the information to a second user equipment, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment.

[0147] The information can be configured for the first user equipment for transmitting a physical layer signal. The physical layer signal can comprise a sounding reference signal. Transmitting the information to the second user equipment can comprise signaling the information broadcast in a beam from the apparatus. The information can comprise parameters for the second user equipment to demodulate the transmitted sounding reference signal. The instructions, when executed by the at least one processor, can cause the apparatus to perform: transmitting timing advance downlink control information to the second user equipment in a common search space in a beam from the apparatus. The information transmitted by the apparatus can comprise parameters configured to decode the physical layer signal, wherein the parameters indicate at least a location of the physical layer signal in a time domain and a frequency domain. The information can comprise symbol information in a system information block. The system information block can comprise at least one of: a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate its timing advance. The system information block can comprise information configured for the second user equipment to control a maximum timing advance estimation error. The system information block can comprise parameters configured for the second user equipment to select one or more determined respective timing advances from respective first user equipment in a plurality of first user equipment to transmit signals to the apparatus with timing advance. The instructions, when executed by the at least one processor, can cause the apparatus to perform: transmitting information about switching at the second user equipment between a first timing advance pattern and a different timing advance pattern based at least in part on the physical layer signal received at the second user equipment from the first user equipment. The transmission of the information can be configured to be received at the second user equipment when the second user equipment is in an idle mode. Determining the information about the physical layer signal can comprise selecting the first user equipment from a plurality of user equipment based at least in part on: the first user equipment being in a connected state with the apparatus; and a proximity of the first user equipment to a cell edge of a beam from the apparatus. The instructions, when executed by the at least one processor, can cause the apparatus to perform: determining a bounded estimation error. The instructions, when executed by the at least one processor, can cause the apparatus to perform: scheduling transmission of a symbol for a sounding reference signal for a first user equipment in the plurality of user equipment, and scheduling a symbol adjacent to the sounding reference signal from at least a second user equipment in the plurality of user equipment that is not adjacent to a beam in which the first user equipment is located. The instructions, when executed by the at least one processor, can cause the apparatus to perform: determining that at least one user equipment in the plurality of user equipment is at least one of: stationary, or a fixed wireless access user equipment.

[0148] Reference is also made to Figure 14, according to one example embodiment, a method can be provided that includes determining information related to a physical layer signal to be received by the apparatus, as shown in block 1402, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus, and transmitting, by the apparatus, the information to a second user equipment, as shown in block 1404, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment. The information can be configured for the first user equipment for transmitting the physical layer signal. The physical layer signal can include a sounding reference signal. Transmitting the information to the second user equipment can include broadcasting signaling of the information in a beam from the apparatus. The method can include transmitting timing advance downlink control information to the second user equipment in a common search space in the beam from the apparatus. The information can include parameters for the second user equipment to demodulate the transmitted sounding reference signal. The information can include parameters configured to decode the physical layer signal, wherein the parameters indicate at least a location of the physical layer signal in a time domain and a frequency domain. The information can include symbol information in a system information block. The system information block can include at least one of a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate its timing advance. The system information block can include information configured for the second user equipment to control a maximum timing advance estimation error. The system information block can include parameters configured for the second user equipment to select one or more determined respective timing advances from respective first user equipment of a plurality of first user equipment to transmit a signal to the apparatus with a timing advance. A single TA estimation can be obtained after processing a plurality of TA measurements. Thus, there can be only one final TA estimation that is used to transmit a signal with a timing advance to the network. The method can include transmitting, at the second user equipment, information about switching between a first timing advance pattern and a different timing advance pattern based at least in part on the physical layer signal received at the second user equipment from the first user equipment. The transmission of the information can be configured to be received at the second user equipment when the second user equipment is in an idle mode. The determining of the information related to the physical layer signal can include selecting the first user equipment from a plurality of user equipment based at least in part on: the first user equipment being in a connected state with the apparatus; and a proximity of the first user equipment to a cell edge of a beam from the apparatus. The method can include determining a bounded estimation error. The method can include scheduling a transmission of a symbol for a sounding reference signal for a first user equipment of the plurality of user equipment, and scheduling a symbol adjacent to the sounding reference signal from at least a second user equipment of the plurality of user equipment that is not adjacent to a beam in which the first user equipment is located. The method can include determining that at least one user equipment of the plurality of user equipment is at least one of: stationary or a fixed wireless access user equipment.

[0149] According to one example embodiment, an apparatus comprises means for determining information related to a physical layer signal to be received by the apparatus, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus; and means for transmitting, by the apparatus, the information to a second user equipment, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment.

[0150] According to one example embodiment, instructions executable by an apparatus to perform operations are tangibly embodied in a program storage device readable by the apparatus, the operations comprising: determining information related to a physical layer signal to be received by the apparatus, wherein the physical layer signal is to be transmitted from a first user equipment to the apparatus; and transmitting, by the apparatus, the information to a second user equipment, wherein the information is configured at least in part for the second user equipment for demodulating the physical layer signal transmitted from the first user equipment and received at the second user equipment.

[0151] According to one example embodiment, an apparatus is provided comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: receiving physical layer signals from a plurality of user equipments; determining respective timing advance measurements based at least in part on the received physical layer signals; and selecting, based at least in part on one or more parameters, at least one of the respective timing advance measurements for use in determining a timing advance for the apparatus for transmitting signals to network equipment.

[0152] The physical layer signals can include sounding reference signals. The apparatus can be in an idle mode. The instructions, when executed by the at least one processor, can cause the apparatus to perform receiving, from the network equipment, symbol information about the physical layer signals from the plurality of user equipment. Receiving the symbol information from the network equipment is with downlink control information from the network equipment. The instructions, when executed by the at least one processor, can cause the apparatus to perform receiving, from the network equipment, a system information block including the one or more parameters. The parameters can include at least one of a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate a timing advance of the apparatus. The selecting can include filtering the respective timing advance measurements to use based on at least one of: determining that the physical layer signals and network equipment signals are received with substantially opposite beams; or determining that the user equipment is located proximate to the apparatus based on at least a received power of the physical layer signals. The instructions, when executed by the at least one processor, can cause the apparatus to perform demodulating the received physical layer signals based on information received from the network equipment, where the information includes at least in part the one or more parameters. The information can include sounding reference signal information about the physical layer signals from the plurality of user equipment. The apparatus can be configured to receive the physical layer signals from the plurality of user equipment in at least one first receive beam, and receive signals from the network equipment in a different second receive beam, and the apparatus is configured to determine that the first receive beam and the second receive beam are substantially opposite, and where the selecting is based on the determination that the first receive beam and the second receive beam are substantially opposite. The instructions, when executed by the at least one processor, can cause the apparatus to perform switching between a first timing advance mode and a second timing advance mode based on the physical layer signals from one or more of the plurality of user equipment. The first timing advance mode can be based on a bounded estimation error.

[0153] Reference is also made to Figure 15According to one example embodiment, a method is provided that includes receiving physical layer signals from a plurality of user equipment, as represented by block 1502; determining respective timing advance measurements based at least in part on the received physical layer signals, as represented by block 1504; and selecting, based at least in part on one or more parameters, at least one of the respective timing advance measurements for use in determining a timing advance for the apparatus to use in transmitting signals to network equipment, as represented by block 1506. The physical layer signals can include sounding reference signals. The method can include performing the selecting by the apparatus while the apparatus is in an idle mode. The method can include receiving, from the network equipment, symbol information regarding the physical layer signals from the plurality of user equipment. Receiving the symbol information from the network equipment is with downlink control information from the network equipment. The method can include receiving, from the network equipment, a system information block that includes the one or more parameters. The parameters can include at least one of a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate its timing advance. The selecting can include filtering the respective timing advance measurements to use based on at least one of determining that the physical layer signals and network equipment signals were received with substantially opposite beams; or determining that the user equipment is located near the apparatus based at least on a received power of the physical layer signals. The method can include demodulating the received physical layer signals based on information received from the network equipment, where the information at least partially includes the one or more parameters. The information can include sounding reference signal information regarding the physical layer signals from the plurality of user equipment. The method can include receiving the physical layer signals from the plurality of user equipment in at least one first receive beam and receiving signals from the network equipment in a different second receive beam, and the apparatus is configured to determine that the first receive beam and the second receive beam are substantially opposite, and where the selecting is based on the determination that the first receive beam and the second receive beam are substantially opposite. The method can include switching between a first timing advance mode and a second timing advance mode based on the physical layer signals from one or more of the plurality of user equipment. The first timing advance mode can be based on a bounded estimation error.

[0154] According to one example embodiment, an apparatus is provided that includes means for receiving physical layer signals from a plurality of user equipment; means for determining respective timing advance measurements based at least in part on the received physical layer signals; and means for selecting, based at least in part on one or more parameters, at least one of the respective timing advance measurements for use in determining a timing advance for transmitting signals to network equipment.

[0155] According to one example embodiment, a program storage device readable by a device is provided, tangibly embodying a program of instructions executable by the device to perform operations, the operations comprising: receiving physical layer signals from a plurality of user equipment; determining respective timing advance measurements based at least in part on the received physical layer signals; and selecting at least one of the respective timing advance measurements for determining a timing advance for the device to use for transmitting signals to network equipment based at least in part on one or more parameters.

[0156] According to one example embodiment, a device is provided, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to perform: determining a first timing advance pattern for transmitting signals from the device to network equipment; determining a second timing advance pattern for transmitting signals from the device to the network equipment; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on physical layer signals from one or more user equipment.

[0157] The first timing advance pattern can comprise a timing advance pattern configured to be performed when the device is in an idle mode. The second timing advance pattern can comprise a timing advance pattern configured to be performed when the device is not in an idle mode. The switching can be based at least in part on information received from the network equipment regarding the physical layer signals. The information received from the network equipment regarding the physical layer signals can be received in a system information block from the network equipment. The information received from the network equipment regarding the physical layer signals can comprise information related to sounding reference signals from the one or more user equipment. The switching can be based at least in part on information received from the network equipment regarding transmission scheduling of the physical layer signals from the one or more user equipment. The switching can be based at least in part on information regarding at least one of: a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the device to estimate its timing advance. The switching can be based at least in part on a determination of a first direction of signals from the network equipment relative to at least one second direction of the physical layer signals from the one or more user equipment.

[0158] Reference is also made to Figure 16According to an example embodiment, a method is provided that includes determining a first timing advance pattern for transmitting signals from a device to network equipment, as represented by block 1602; determining a second timing advance pattern for transmitting signals from the device to the network equipment, as represented by block 1604; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on a physical layer signal from one or more user equipment, as represented by block 1606. The first timing advance pattern can include a timing advance pattern configured to be performed when the device is in an idle mode. The second timing advance pattern can include a timing advance pattern configured to be performed when the device is not in an idle mode. The switching can be based at least in part on information received from the network equipment regarding the physical layer signal. The information received from the network equipment regarding the physical layer signal can be received in a system information block from the network equipment. The information received from the network equipment regarding the physical layer signal can include information related to a sounding reference signal from the one or more user equipment. The switching can be based at least in part on information received from the network equipment regarding a transmission schedule of the physical layer signal from the one or more user equipment. The switching can be based at least in part on information regarding at least one of: a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the device to estimate its timing advance. The switching can be based at least in part on a determination of a first direction of a signal from the network equipment relative to at least one second direction of the physical layer signal from the one or more user equipment.

[0159] According to an example embodiment, an apparatus is provided that includes means for determining a first timing advance pattern for transmitting signals from a device to network equipment; means for determining a second timing advance pattern for transmitting signals from the device to the network equipment; and means for switching between the first timing advance pattern and the second timing advance pattern based at least in part on a physical layer signal from one or more user equipment.

[0160] According to an example embodiment, a program storage device readable by a device tangibly embodying a program of instructions executable by the device for performing operations is provided, the operations including determining a first timing advance pattern for transmitting signals from a device to network equipment; determining a second timing advance pattern for transmitting signals from the device to the network equipment; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on a physical layer signal from one or more user equipment.

[0161] According to an example embodiment, an apparatus is provided comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: transmitting, by the apparatus, first information to a first user equipment, wherein the first information is configured at least in part for the first user equipment to demodulate a physical layer signal transmitted from a second user equipment and received at the first user equipment; and transmitting, by the apparatus, second information to the first user equipment, wherein the second information comprises symbol information related to the physical layer signal. The second information can comprise timing advance downlink control information in a common search space from a network device. The first information can comprise a system information block. The instructions, when executed by the at least one processor, can cause the apparatus to perform: scheduling transmission of a symbol for a sounding reference signal for the second user equipment, and scheduling a symbol adjacent to the sounding reference signal, the sounding reference signal being from another user equipment in a beam from the apparatus that is not adjacent to a beam in which the first user equipment is located. The instructions, when executed by the at least one processor, can cause the apparatus to perform: selecting the second user equipment to be one of: stationary, or slowly moving, or a fixed wireless access user equipment. The apparatus can determine a bounded estimation error, and configure a first timing advance pattern based on the determined bounded estimation error.

[0162] As used herein, the term “non-transitory” is a limitation of the medium itself (i.e., tangible, not a signal), not a limitation of data storage durability (e.g., RAM vs. ROM).

[0163] As used in this application, the term “circuitry” can refer to one or more or all of the following: (a) hardware-only circuitry implementations (such as implementations in only analog and / or digital circuitry). (b) combinations of hardware circuits and software such as, for example: (i) combinations of analog and / or digital hardware circuits with software / firmware and (ii) portions of hardware processor(s) with software (including digital signal processors), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions and (iii) hardware circuitry, such as a microprocessor(s) or a portion of a microprocessor, that requires software (e.g., firmware) for operation, but software is not present when it is not needed for operation.

[0164] Such definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation that is at least partially functional and / or an implementation that is at least partially software and / or firmware in addition to an implementation that is at least partially hardware. For example, if applicable, the term circuitry also covers a baseband integrated circuit or processor integrated circuit for a mobile device or server, cellular network device, or other computing or network device that is similar in function and / or structure to a baseband integrated circuit or processor integrated circuit.

[0165] It is to be understood that the above description is illustrative only. Various alternative and modifications can be devised by those skilled in the art without departing from the scope of the claims. For example, features recited in the various dependent claims can be combined with each other in any appropriate combination. Furthermore, features from different embodiments described above can be selectively combined into new embodiments. Accordingly, the description is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the appended claims.

[0166] In addition, various implementations of the disclosure can be described with reference to the following clauses, which can be combined in any reasonable manner:

[0167] Clause 1. An apparatus for wireless communication, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: receiving physical layer signals from a plurality of user equipment; determining respective timing advance measurements based at least in part on the received physical layer signals; and selecting, based at least in part on one or more parameters, at least one of the respective timing advance measurements for use in determining a timing advance for the apparatus to use in transmitting signals to network equipment.

[0168] Clause 2. The apparatus of clause 1, wherein the physical layer signals comprise sounding reference signals.

[0169] Clause 3. The apparatus of clause 1, wherein the apparatus is in an idle mode.

[0170] Clause 4. The apparatus of clause 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to perform: receiving, from the network equipment, symbol information regarding the physical layer signals from the plurality of user equipment.

[0171] Clause 5. The apparatus of clause 4, wherein receiving the symbol information from the network equipment is with downlink control information from the network equipment.

[0172] Clause 6. The apparatus of clause 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to perform: receiving, from the network equipment, a system information block comprising the one or more parameters.

[0173] Clause 7. The apparatus of clause 1, wherein the parameters comprise at least one of: a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate a timing advance.

[0174] Clause 8. The apparatus of clause 1, wherein the selecting comprises filtering the respective timing advance measurements to use based on at least one of: determining that the physical layer signals and network equipment signals are received in substantially opposite beams, or determining that the user equipment is located in proximity to the apparatus based on at least a received power of the physical layer signals.

[0175] Clause 9. The apparatus of clause 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to perform: demodulating the received physical layer signals based on information received from the network equipment, wherein the information comprises at least in part the one or more parameters.

[0176] Clause 10. The apparatus of clause 9, wherein the information comprises sounding reference signal information regarding the physical layer signals from the plurality of user equipment.

[0177] Clause 11. The apparatus of clause 1, wherein the apparatus is configured to receive the physical layer signals from the plurality of user equipment in at least one first receive beam and to receive signals from the network equipment in a different second receive beam, and the apparatus is configured to determine that the first receive beam and the second receive beam are substantially opposite, and wherein the selecting is based on the determination that the first receive beam and the second receive beam are substantially opposite.

[0178] Clause 12. The apparatus of any of clauses 1-11, wherein the instructions, when executed by the at least one processor, cause the apparatus to perform: switching between a first timing advance mode and a second timing advance mode based on the physical layer signals from one or more of the plurality of user equipment.

[0179] Clause 13. The apparatus of clause 12, wherein the first timing advance mode is based on a bounded estimation error.

[0180] Clause 14. A method for wireless communication, comprising: receiving physical layer signals from a plurality of user equipments; determining respective timing advance measurements based at least in part on the received physical layer signals; and selecting, based at least in part on one or more parameters, at least one of the respective timing advance measurements for use in determining a timing advance for transmitting signals to network equipment.

[0181] Clause 15. An apparatus for wireless communication, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: determining a first timing advance pattern for transmitting signals from the apparatus to network equipment; determining a second timing advance pattern for transmitting signals from the apparatus to the network equipment; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on physical layer signals from one or more user equipments.

[0182] Clause 16. The apparatus of Clause 15, wherein the first timing advance pattern comprises a timing advance pattern configured to be performed when the apparatus is in an idle mode.

[0183] Clause 17. The apparatus of Clause 15, wherein the second timing advance pattern comprises a timing advance pattern configured to be performed when the apparatus is not in an idle mode.

[0184] Clause 18. The apparatus of Clause 15, wherein the switching is based at least in part on information received from the network equipment regarding the physical layer signals.

[0185] Clause 19. The apparatus of Clause 18, wherein the information received from the network equipment regarding the physical layer signals is received in a system information block from the network equipment.

[0186] Clause 20. The apparatus of Clause 18, wherein the information received from the network equipment regarding the physical layer signals comprises information related to sounding reference signals from the one or more user equipments.

[0187] Clause 21. The apparatus of Clause 18, wherein the switching is based at least in part on information received from the network equipment regarding transmission scheduling of the physical layer signals from the one or more user equipments.

[0188] Clause 22. The apparatus of clause 18, wherein the switching is based at least in part on information regarding at least one of: a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate a timing advance.

[0189] Clause 23. The apparatus of any of clauses 18 to 21, wherein the switching is based at least in part on a determination of a first direction of a signal from the network equipment relative to at least one second direction of the physical layer signals from the one or more user equipment.

[0190] Clause 24. A method for wireless communication, comprising: determining a first timing advance pattern for transmitting signals from an apparatus to network equipment; determining a second timing advance pattern for transmitting signals from the apparatus to the network equipment; and switching between the first timing advance pattern and the second timing advance pattern based at least in part on physical layer signals from one or more user equipment.

Claims

1. An apparatus for wireless communication, comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: receiving physical layer signals from a plurality of user equipments; determining respective timing advance measurements based at least in part on the received physical layer signals; and selecting, based at least in part on one or more parameters, at least one of the respective timing advance measurements for determining a timing advance for the apparatus to use for transmitting signals to a network equipment.

2. The apparatus of claim 1, wherein the physical layer signals comprise sounding reference signals.

3. The apparatus of claim 1, wherein the apparatus is in an idle mode.

4. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to perform: receiving, from the network equipment, symbol information about the physical layer signals from the plurality of user equipments.

5. The apparatus of claim 4, wherein receiving the symbol information from the network equipment is with a downlink control information from the network equipment.

6. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to perform: receiving, from the network equipment, a system information block comprising the one or more parameters.

7. The apparatus of claim 1, wherein the parameters comprise at least one of: a threshold reference signal received power, or a number representing a minimum number of timing advance measurements available to the apparatus to estimate its timing advance.

8. The apparatus of claim 1, wherein the selecting comprises filtering the respective timing advance measurements to use based on at least one of: determining that the physical layer signals and network equipment signals are received with approximately opposite beams, or determining that the user equipment is located near the apparatus based at least on received power of the physical layer signals.

9. The apparatus of claim 1, wherein the instructions, when executed by the at least one processor, cause the apparatus to perform: demodulating the received physical layer signals based on information received from the network equipment, wherein the information comprises at least in part the one or more parameters.

10. The apparatus of claim 9, wherein the information comprises sounding reference signal information about the physical layer signals from the plurality of user equipments.

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