AIOT multi-point positioning method

Abstract

The invention relates to an AIOT multi-point positioning method. An apparatus comprises means for measuring a reception time of an activation signal triggering a response; means for determining the transmission time of the response; and means for determining the received transmission time difference as the difference between the transmission time of the response and the reception time of the activation signal triggering the response.

Description

Technical Field

[0001] Example and non - limiting example embodiments generally relate to communications, and more particularly to AIoT multi - point positioning methods. Background Art

[0002] It is known that communication devices access a communication network via access network nodes. Summary of the Invention

[0003] According to one aspect, a device includes components for measuring the reception time of an activation signal that triggers a response; components for determining the transmission time of the response; and components for determining the reception - transmission time difference as the difference between the transmission time of the response and the reception time of the activation signal that triggers the response. Brief Description of the Drawings

[0004] The foregoing aspects and other features are explained in the following description in conjunction with the drawings.

[0005] Figure 1 is a block diagram of one possible and non - limiting system in which example embodiments may be practiced.

[0006] Figure 2 Shows an example topology (Topology 1) of the communication between a base station and an ambient IoT device.

[0007] Figure 3 Shows an example topology (Topology 2) of the communication between a base station and an intermediate node, and the communication between the intermediate node and an ambient IoT device.

[0008] Figure 4A Shows an example topology (Topology 3) with downlink assistance.

[0009] Figure 4B Shows an example topology (Topology 3) with uplink assistance.

[0010] Figure 5 Shows an example topology (Topology 4) of the communication between a UE and an ambient AIoT device.

[0011] Figure 6 is an example signaling diagram based on the examples described herein.

[0012] Figure 7 is an example device configured to implement the examples described herein.

[0013] Figure 8 Shows a representation of an example of a non - volatile storage medium for storing instructions for implementing the examples described herein.

[0014] Figure 9 is an example method based on the examples described herein.

[0015] Figure 10 is an example method based on the examples described herein.

[0016] Figure 11 is an example method based on the examples described herein.

[0017] Figure 12 is an example method based on the examples described herein.

[0018] Figure 13 is an example method based on the examples described herein.

[0019] Figure 14 is an example method based on the examples described herein.

[0020] Figure 15 is an example method based on the examples described herein. Detailed implementation

[0021] Turning Figure 1 , the figure shows a block diagram of one possible non - restrictive example in which the examples can be practiced. A user equipment (UE) 110, a radio access network (RAN) node 170, and (a) network element(s) 190 are shown. In Figure 1In the example, user equipment (UE) 110 wirelessly communicates with a wireless network 100. The UE is a wireless device that can access the wireless network 100. UE 110 includes one or more processors 120, one or more memories 125, and one or more transceivers 130 interconnected by 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 interconnect mechanism, such as a series of lines on a motherboard or integrated circuit, optical fiber, or other optical communication devices. 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. UE 110 includes a module 140 that includes one or both of parts 140-1 and / or 140-2, and the module can be implemented in various ways. Module 140 can be implemented in hardware as module 140-1, such as being implemented as part of one or more processors 120. Module 140-1 can also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, module 140 can be implemented as module 140-2, which is implemented as computer program code 123 and executed by one or more processors 120. For example, the one or more memories 125 and the computer program code 123 can be configured to, together with the one or more processors 120, cause the user equipment 110 to perform one or more of the operations described herein. UE 110 communicates with the RAN node 170 via a wireless link 111.

[0022] In this example, the RAN node 170 is a base station that provides access to the wireless network 100 for wireless devices such as the UE 110. The RAN node 170 can be, for example, a base station for 5G, also known as New Radio (NR). In 5G, the RAN node 170 can be an NG-RAN node, which is defined as a gNB or an ng-eNB. A gNB is a node that provides NR user plane and control plane protocol termination towards the UE and is connected to the 5GC (such as, for example, the (one or more) network elements 190) via an NG interface (such as connection 131). An ng-eNB is a node that provides E-UTRA user plane and control plane protocol termination towards the UE and is connected to the 5GC via an NG interface (such as connection 131). The NG-RAN node can include multiple gNBs, and the gNB can also include a Central Unit (CU) (gNB-CU) 196 and the (one or more) Distributed Units (DU) (gNB-DU), where the DU 195 is shown. Note that the DU 195 can include or be coupled to and control a Radio Unit (RU). The gNB-CU 196 is a logical node that hosts the Radio Resource Control (RRC), SDAP, and PDCP protocols of the gNB or controls the operation of one or more gNB-DUs and the RRC and PDCP protocols of the en-gNB. The gNB-CU 196 terminates the F1 interface connected to the gNB-DU 195. The F1 interface is shown as reference numeral 198, although reference numeral 198 also shows the link between the remote element of the RAN node 170 and the centralized element of the RAN node 170, such as the link between the gNB-CU 196 and the gNB-DU 195. The gNB-DU 195 is a logical node that hosts the RLC, MAC, and PHY layers of the gNB or en-gNB, and its operation is partially controlled by the gNB-CU 196. One gNB-CU 196 supports one or more cells. One cell can be supported by one gNB-DU 195, or one cell can be supported / shared with multiple DUs under RAN sharing. The gNB-DU 195 terminates the F1 interface 198 connected to the gNB-CU 196. Note that the DU 195 is considered to include a transceiver 160, for example, as part of the RU, but some examples in this regard can make the transceiver 160 as part of a separate RU, for example, under the control of the DU 195 and connected to the DU 195. The RAN node 170 can also be an eNB (evolved NodeB) base station for LTE (Long Term Evolution), or any other suitable base station or node.

[0023] The RAN node 170 includes one or more processors 152, one or more memories 155, one or more network interfaces (N / W I / F) 161, and one or more transceivers 160 interconnected by 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 may include the (multiple) processors 152, one or more memories 155, and the network interface 161. Note that the DU 195 may also include its own one / more memories and the (multiple) processors, and / or other hardware, but these are not shown.

[0024] The RAN node 170 includes a module 150, which includes one or both of parts 150-1 and / or 150-2, and the module can be implemented in various ways. The module 150 can be implemented in hardware as the module 150-1, such as being implemented as part of one or more processors 152. The module 150-1 can also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the module 150 can be implemented as the module 150-2, which is implemented as computer program code 153 and executed by one or more processors 152. For example, the one or more memories 155 and the computer program code 153 are configured to work with the one or more processors 152 such that the RAN node 170 performs one or more of the operations described herein. Note that the functions of the module 150 can be distributed, such as being distributed between the DU 195 and the CU 196, or implemented individually in the DU 195.

[0025] One or more network interfaces 161 communicate via a network, such as via links 176 and 131. Two or more gNBs 170 can communicate using, for example, the link 176. The link 176 can be wired or wireless or both, and can implement, for example, the Xn interface for 5G, the X2 interface for LTE, or other suitable interfaces for other standards.

[0026] 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 optic or other optical communication devices, wireless channels, etc. For example, one or more transceivers 160 can be implemented as a remote radio head (RRH) 195 for LTE or a distributed unit (DU) 195 implemented for a gNB in 5G, where other elements of the RAN node 170 may be physically located at a different location from the RRH / DU 195, and one or more buses 157 can be partially implemented as, for example, a fiber optic cable or other suitable network connection for connecting other elements of the RAN node 170 (e.g., a central unit (CU), gNB-CU 196) to the RRH / DU 195. Reference numeral 198 also indicates these suitable (multiple) network links.

[0027] The RAN node / gNB can include one or more TRPs, and the methods described herein can be applied to the TRP. Figure 1 It is shown that the RAN node 170 includes TRP 51 and TRP 52 in addition to the TRP represented by the transceiver 160. Similar to the transceiver 160, each of the TRP 51 and TRP 52 can include a transmitter and a receiver. The RAN node 170 can host or include Figure 1 other TRPs not shown.

[0028] The relay node in NR is called an integrated access and backhaul node. The mobile terminal part of the IAB node facilitates the backhaul (parent link) connection. In other words, the mobile terminal part includes functions carrying UE functions. The distributed unit part of the IAB node facilitates the so-called access link (sub-link) connection (i.e., for access link UEs and, in the case of multi-hop IAB, for the backhaul of other IAB nodes). In other words, the distributed unit part is responsible for certain base station functions. The IAB scenario can follow the so-called split architecture, where the central unit hosts high-layer protocols for the UE and terminates the control plane and user plane interfaces with the 5G core network.

[0029] Note that the description herein indicates that a "cell" performs functions, but it should be clear that the devices forming the cell can perform the functions. A cell forms part of a base station. That is, each base station can have multiple cells. For example, a single carrier frequency and associated bandwidth can have three cells, and each cell covers one-third of the 360-degree area, so the coverage area of a single base station covers an approximately elliptical or circular shape. In addition, each cell can correspond to a single carrier and the base station can use multiple carriers. So if each carrier has 3 120-degree cells and there are 2 carriers, the base station has a total of 6 cells.

[0030] The wireless network 100 may include one or more network elements 190, which may include core network functions and provide connectivity to other networks such as telephone networks and / or data communication networks (e.g., the Internet) via one or more links 181. Such core network functions for 5G may include Location Management Function (LMF) and / or Access and Mobility Management Function(s) (AMF) and / or User Plane Function (UPF) and / or Session Management Function(s) (SMF). Such core network functions for LTE may include MME (Mobility Management Entity) / SGW (Serving Gateway) functions. Such core network functions may include Self-Organizing / Optimizing Network (SON) functions. These are merely example functions that may be supported by the network element(s) 190, and note that both 5G and LTE functions may be supported. The RAN node 170 is coupled to the network element 190 via the link 131. The link 131 may be implemented as, for example, the NG interface for 5G, or the S1 interface for LTE, or other suitable interfaces 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 by one or more buses 185. The one or more memories 171 include computer program code 173. The computer program code 173 may include SON and / or MRO functions 172.

[0031] The wireless network 100 may implement network virtualization, which is the process of combining hardware and software network resources and network functions into a single software-based management entity or virtual network. Network virtualization involves platform virtualization, which is typically combined with resource virtualization. Network virtualization is divided into external network virtualization or internal network virtualization. External network virtualization combines many networks or network parts into virtual units, and internal network virtualization provides network-like functions for software containers on a single system. Note that the virtualized entities resulting from network virtualization still use hardware such as processors 152 or 175 and memories 155 and 171 to some extent, and such virtualized entities also produce technical effects.

[0032] The computer-readable memories 125, 155, and 171 can be of any type suitable for 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, non-transitory memory, transitory memory, fixed memory, and removable memory. The computer-readable memories 125, 155, and 171 can be components for performing storage functions. The processors 120, 152, and 175 can be of any type suitable for the local technical environment, and by way of non-limiting example, can include one or more of a general-purpose computer, a special-purpose computer, a microprocessor, a digital signal processor (DSP), and a processor based on a multi-core processor architecture. The processors 120, 152, and 175 can be components for performing functions such as control of the UE 110, RAN node 170, (one or more) network elements 190, and other functions described herein.

[0033] Generally, various example embodiments of the user equipment 110 can include, but are not limited to, a cellular phone with wireless communication capabilities (such as a smart phone, a tablet computer, a personal digital assistant (PDA)), a portable computer with wireless communication capabilities, an image capture device with wireless communication capabilities (such as a digital camera), a gaming device with wireless communication capabilities, a music storage and playback device with wireless communication capabilities, an Internet device (including a device that allows wireless Internet access and browsing), a tablet computer with wireless communication capabilities, a head-mounted display (such as a display that implements virtual / augmented / mixed reality), and a portable unit or terminal that combines such functions in a combination. The UE 110 can also be a vehicle such as an automobile, or a UE installed in a vehicle, a UAV such as a drone, or a UE installed in a UAV. The user equipment 110 can be a terminal device, such as a mobile phone, a mobile device, a sensor device, etc., which is a device used or not used by a user.

[0034] The UE 110, RAN node 170, and / or (one or more) network elements 190 (and associated memories, computer program code, and modules) can be configured to implement (e.g., partially) the methods described herein. Thus, Figure 1 The computer program code 123, modules 140-1, modules 140-2, and other elements / features of the UE 110 shown can implement the user equipment-related aspects of the examples described herein. Similarly, Figure 1 The computer program code 153, modules 150-1, modules 150-2, and other elements / features of the RAN node 170 shown can implement the gNB / TRP-related aspects of the examples described herein. Figure 1The computer program code 173 of the (multiple) network elements 190 and other elements / features shown can be configured to implement the network element-related aspects of the examples described herein.

[0035] Therefore, after introducing a suitable but non-limiting technical context for the practice of the example embodiments, the example embodiments will now be described more specifically.

[0036] Regarding IoT applications, 3GPP has specified NB-IoT / eMTC and NR RedCap before R18 to meet the requirements of wide-area IoT communication for low-cost and low-power devices. These IoT devices typically consume tens or hundreds of milliwatts of power during transceiver operation, and cost only a few dollars. However, to achieve the interconnection of all things, IoT devices with a cost and power consumption reduced to one-tenth or even one-hundredth are needed, especially for a large number of applications that require battery-free devices.

[0037] 1. Typical use cases

[0038] In recent years, the number of IoT connections has grown rapidly and is expected to reach hundreds of billions by 2030. As more and more 'things' are expected to be interconnected to improve production efficiency and increase living comfort, there is a requirement to further reduce the size, cost, and power consumption of IoT devices. In particular, due to the huge consumption of materials and manpower, it is impractical to replace the batteries of all IoT devices regularly. Using the energy collected from the environment to power IoT devices to achieve self-sustainable communication has become a trend, especially in applications with a large number of devices (e.g., ID tags and sensors).

[0039] 2. 3GPP technologies

[0040] The most critical issue in existing 3GPP technologies for the target use cases is the ability to cooperate with energy harvesting considering the limited device size. Cellular devices typically consume tens or even hundreds of milliwatts of power for transceiver processing. Taking the NB-IoT module as an example, with a supply voltage higher than 3.1V, the typical current consumption for receive processing is about 60mA, and for transmit processing at 0dBm transmit power, the current consumption is 70mA. In addition, considering the small size of a typical device of a few square centimeters, the output power provided by a typical energy harvester is mostly below 1 milliwatt. Since the available power is much lower than the consumed power, it is impractical to directly power cellular devices through energy harvesting in most cases.

[0041] A possible solution is to integrate energy harvesting with rechargeable batteries or supercapacitors. However, there are still some problems to be solved. First, in practical situations, the lifetimes of both rechargeable batteries and supercapacitors may be shortened. It is difficult to provide a constant charging current or voltage through energy harvesting, and due to the small output power of the energy harvester, long-term continuous charging is required. Unstable charging current and long-term continuous charging are both harmful to battery life. For supercapacitors, their lifetimes in high-temperature environments will be significantly shortened (e.g., less than 3 years at 50 degrees Celsius). Second, the device size will increase significantly. Small button batteries can only provide a current of dozens of milliamperes, and much larger batteries (e.g., AA batteries) are usually used to power cellular devices, and their sizes may even be larger than the module itself. To store energy within an appropriate working time (e.g., one second), the capacitance required for a supercapacitor is one hundred millifarads. The size of such a supercapacitor may be larger than the NB-IoT module. Third, both rechargeable batteries and supercapacitors may be more expensive than the module itself. Even when purchased in large quantities, the cost of a suitable battery or supercapacitor may reach one dollar or several dollars, which is almost twice the device cost.

[0042] 3. Non-3GPP Technologies

[0043] RFID is the most well-known technology supporting battery-free tags (devices). The power consumption of commercial passive RFID tags can be as low as 1 micro-watt. The technologies for achieving such low power consumption are envelope detection for downlink data reception and backscatter communication for uplink data transmission. RFID is designed for short-range communication, and its typical effective range is less than 10 meters. Since the air interface of RFID has remained almost unchanged since 2005, the overly simple transmission scheme has become an obstacle to improving its link budget and supporting the ability of scalable networks.

[0044] Attracted by the extremely low power consumption of backscatter communication, many non-3GPP technologies have started to invest in related research, such as Wi-Fi, Bluetooth, UWB, and LORA. Various studies have shown that passive tags based on the above air interfaces or with minor modifications to them can support power consumption of several micro-watts or dozens of micro-watts. A large part of the research is aimed at long-range communication. Among them, LoRa tags implemented using commercial off-the-shelf components can send their sensed data to a receiver 381 meters away. Currently, most research focuses on independent and detailed technologies for various optimization goals. It is difficult to see a comprehensive system design that fully meets the requirements of the target use case. However, the standardization of these technologies is agile and fast because these industries usually follow some de facto standards. This means that after showing competitiveness in certain applications, many products on the market can even follow private standards.

[0045] 4.3GPP Activities in Ambient IoT

[0046] A passive radio is a device that utilizes the energy of wireless signals transmitted on a specific carrier and / or bandwidth and charges a simple circuit system, and after being activated, it transmits / reflects a signal encoding at least the ID of the passive radio. The typical system architecture around a passive radio includes (1 - 3):

[0047] 1. Activator: A device that sends an activation signal to wake up the passive radio.

[0048] 2. Passive radio: Utilizes the energy within a certain frequency range and listens for the activation signal. After detecting such a signal, the passive radio transmits / reflects a signal specific to the ID of that radio.

[0049] 3. Reader: A device that listens for and detects passive radio signals. The reader can be collocated with the activator or can be non - collocated with the activator.

[0050] RAN - level research projects have been approved, and the following two main types of devices have been identified recently in RAN#98 - e (RP - 223396):

[0051]

[0052] The objectives of this research project can be grouped into three aspects: (i) deployment scenarios; (ii) design objectives; and (iii) performance evaluation. Regarding deployment scenarios, operation in unlicensed spectrum has been emphasized:

[0053]

[0054]

[0055] 5. Overview of 3GPP Protocols Related to Ambient IoT So Far

[0056] In RAN#98ec, it was agreed to focus on three types of devices (1 - 3): 1. Device A: A passive device without energy storage, 2. Device B: A passive device with energy storage, 3. Device C: An active device with energy storage.

[0057] Power consumption design objective: Device A ≤ 10 μW, Device A < Device B < Device C, Device C ≤ 1 mW

[0058] Device complexity design objective: Device A: Comparable to UHF RFID, Device A ≤ Device B ≤ Device C, Device C: Several orders of magnitude lower than NB - IoT

[0059] During RAN#99, the rapporteur listed the following functions that the ambient IoT in RAN needs to address:

[0060]

[0061]

[0062]

[0063] 6. Topology agreed upon in FS_Ambient_IoT_RAN (TR 38.848)

[0064] For the purpose of research, the following connection topologies of the ambient IoT network and devices are defined. In all these topologies, the ambient IoT devices can be provided with carriers from (multiple) other nodes inside or outside the topology. The links in each topology can be bidirectional or unidirectional. The BS, UE, auxiliary node or intermediate node can be multiple BSs or UEs accordingly. The mixing of indoor and outdoor placement of such nodes is considered a network implementation option.

[0065] 6.1 Topology 1: BS <-> AIoT device

[0066] In Topology 1 (as Figure 2 shown), the ambient IoT device 202 communicates directly and bidirectionally with the base station 170. The communication between the base station 170 and the ambient IoT device 202 includes ambient IoT data and / or signaling (204). This topology includes the possibility that the BS sending to the ambient IoT device is different from the BS receiving from the ambient IoT device.

[0067] 3.6.2 Topology 2: BS <-> Intermediate node <-> AIoT device

[0068] In Topology 2 (as Figure 3 shown), the ambient IoT device 202 communicates bidirectionally with the intermediate node 304 between the device 202 and the base station 170. In this topology, the intermediate node 304 can be a relay capable of ambient IoT, an IAB node, a UE110, a repeater, etc. The intermediate node 304 transmits information between the BS170 and the ambient IoT device 202.

[0069] 6.3 Topology 3: BS <-> Auxiliary node <-> AIoT device <-> BS device

[0070] In Topology 3 (as Figure 4A and Figure 4BIn the scenario shown in the figure, the environmental IoT device 202 sends data / signaling 410 to the base station 170 and receives data / signaling 412 from the auxiliary node 406; or the environmental IoT device 202 receives data / signaling 414 from the base station 170 and sends data / signaling 416 to the auxiliary node 406. In this topology, the auxiliary node 406 can be a relay capable of environmental IoT, IAB, UE 110, repeater, etc.

[0071] 6.4 Topology 4: UE <-> AIoT Device

[0072] In Topology 4 (as Figure 5 shown in the figure), the environmental IoT device 202 communicates bidirectionally with the UE 110. The communication between the UE 110 and the environmental IoT device 202 includes environmental IoT data and / or signaling 502.

[0073] A method for 5G NR multi-RTT positioning is defined in 3GPP TS 37.355. This method is designed for 5G UEs, where each RTT session is allocated individual resources and no interference occurs. However, this method has not been extended to any type of AIOT device yet.

[0074] Locating an AIOT device requires the device to: (1) measure and report positioning signals from multiple sources, or (2) send positioning signals that can be detected and measured by multiple receivers after it has been charged and activated.

[0075] When synchronization is not possible, the only viable method is still RTT, where the AIOT device must perform tasks 1 and 2 one by one. In addition to signal transmission and measurement, the AIOT device also needs to (3) report the RX-TX time difference through a separate communication channel.

[0076] Performing 1, 2, and 3 by an AIOT device is challenging because: a) depending on the device type (A, B, or C), it may have sufficient charge and / or intelligence to only perform a subset of tasks 1, 2, and 3, and b) the transmission of positioning signals and RX-TX time differences from multiple AIOT devices can cause high AIOT cross-interference because the density of these devices may be many orders of magnitude higher than that of typical NR UEs (and thus orthogonality in the frequency domain is no longer realistic).

[0077] An AIOT multi-point positioning method that does not require the location of a known activator is described in this article. This method consists of the following elements (1 - 4):

[0078] 1. The AIoT device is required to calculate the Hybrid RX-TX Time Difference (HRTTD), where (a - b): a. The RX time is the reception time of the activation signal, and b. The TX time is the transmission time of the AIoT response. Note that the TX time includes all delays associated with, for example, charging the device, switching the RX chain to the TX chain, etc. In this way, the activation signal replaces one of the positioning signals in the standard RTT. The AIoT device requires continuous lighting signals for device types A and B, while device type C can operate without a continuous lighting source.

[0079] 2. The AIoT device is required to encode the quantized Hybrid RX-TX Time Difference in its own response, for example, by modulating the response using a bitstream encoding the quantized version of HRTTD (referred to as qHRTTD).

[0080] 3. The reader is required to report the Hybrid RX-TX Time Difference, where (a - d): a. The RX time is the reception time of the AIoT response, and b. The TX time is the transmission time of the activation signal transmitted by the activator radio rather than by the reader itself. c. To achieve this behavior, the activator and the reader need to be synchronized, and the reader should know the TX time of the activation signal. This can be achieved through pre-configuration of the NR NW control of the reading session. d. In addition to the HRTTD measured by itself, the reader also reports qHRTTD. In an alternative implementation, the reader can de-quantize qHRTTD itself and relay the result.

[0081] 4. The session control unit (e.g., LMF) receives the HRTTD and qHRTTD, de-quantizes qHRTTD and calculates the difference between the two, thereby eliminating the offset caused by the propagation delay of the activator AIoT device and the deviation of the AIoT clock relative to the reader.

[0082] The advantages and technical effects of the examples described herein include AIoT positioning that does not require (e.g., without the need for) synchronizing the AIoT device to the NW time, and the AIoT device does not need to explicitly report the RX-TX time difference, thereby minimizing the reporting overhead. The AIoT device can also be referred to as a tag or tagging device.

[0083] Solution 1

[0084] The process is as Figure 6 shown in the flowchart of, where the new signaling elements are in red and the new AIoT device methods are in purple. Specifically:

[0085] The Signal 1(601) element is a new IE in the LPP auxiliary data. B1 and B2 refer to the number of bits dedicated to quantifying the integer part and the fractional part of the HRTTD calculated by the AIOT device. Note that if the activator 620 and / or the reader 630 are changed to be located in the gNB 170, the auxiliary data is changed to be sent through the NRPPa interface. This configuration is executed by the LMF 190 and includes an explicit request for the HRTTD calculation 606 performed by the AIOT device 202 and the reader 630.

[0086] The AIOT HRTTD measurement needs to be standardized so that the AIOT device 202 understands how to obtain it after the LMF 190 issues a request (e.g., a new physical layer measurement in TS 38.215). The AIOT HRTTD measurement request can be made by defining a new IE in the LPPRequestLocationInformation.

[0087] The definition of AIOT HRTTD can be standardized as the difference between the TX time of the AIOT response 609 and the RX time of the activation signal (602) that triggers the AIOT response 609, specifically, (i - ii): i) The RX time is the reception time of the activation signal 602, and ii) The TX time is the transmission time of the AIOT response 609. Note that the TX time includes all delays related to, for example, charging the device, switching the RX chain to the TX chain, etc. In this way, the activation signal 602 replaces one of the positioning signals from the standard RTT. The AIOT device 202 requires continuous illumination signals for device types A and B, while device type C can operate without a continuous illumination source.

[0088] The reader HRTTD measurement also needs to be standardized (e.g., a new physical layer measurement in TS 38.215). The reader HRTTD measurement request can be made by defining a new IE in the LPP RequestLocationInformation.

[0089] The definition of reader HRTTD can be standardized as the difference between the TX time of the activation signal 602 and the RX time of the AIOT response 609 triggered by the activation signal 602 above, specifically, (i - ii): i) The RX time is the reception time of the AIOT response 609, and ii) The TX time is the transmission time of the activation signal 602 performed by the activator radio 620 rather than by the reader 630 itself.

[0090] The signal 12(612) consists of new IEs in the Location Information Message provided by LPP. Note that if the activator 620 and / or the reader 630 are changed to be located in the gNB 170, the report is changed to be sent via the NRPPa interface. The signal 612 must be received from multiple readers 630 so that the LMF 190 can perform triangulation / polygon measurement on the location of the AIoT device 202.

[0091] The step-by-step process in the case where the LMF 190 triggers a session is described in detail below Figure 6 below.

[0092] In step 1, the LMF 190 configures and triggers a session of the activator 620, the reader 630, and the AIoT device 202. Specifically, via the LPP assistance information, the LMF 190 configures (a-c): a. the activation signal transmission, including time and frequency resources, waveform, etc., b. the AIoT ID to be localized, c. the IDs of the activator and (multiple) readers related to the localization of the AIoT device. Then, via the LPP RequestLocationInformation, the LMF 190 can address the AIoT device 202 and the AIoT reader 630, and request the calculation of the AIoT HRTTD, and accordingly calculate the reader HRTTD and the AIoT qHRTTD.

[0093] In step 2(602), as a result of the above configuration (601), the activator 620 sends the corresponding activation signal that is at least received by the AIoT device 202.

[0094] d. According to the activator-reader distance, the activation signal can also be received by the reader 630. Specifically, if the reader 630 is exactly within the activation coverage, the reader 630 can receive the activation signal. In this case, if the activation signal 602 and the AIoT device signal (609) overlap (the tag signal 609 is the signal received from the AIoT device 202), the reader 630 should first cancel the activation signal 602, and then attempt tag detection. To achieve this, the reader 630 should know the activation signal in advance, and apply any available interference cancellation method to subtract the contribution of the activation signal 602 from the total received signal (where the total received signal corresponds to the activation signal 602 and the AIoT response 609).

[0095] In step 3(603), in response to the activation signal 602, the AIoT device 202 performs the calculation of the HRTTD 606 and the generation of the response of the embedded quantization version (i.e., qHRTTD), regarding Figure 6For the details of step 4 (604), step 5 (605), step 6 (606), step 7 (607) and step 8 (608), please refer to Solution 3.

[0096] In steps 10 (610) and 11 (611), the reader 630 detects the AIOT response 609 and calculates the reader HRTTD as described above.

[0097] In step 11 (611), based on the waveform characteristics of the response, the reader 630 also reconstructs the qHRTTD into a bit vector.

[0098] In step 12 (612), the reader 630 uses the new LPP ProvideLocationInformation IE to report both the HRTTD and qHRTTD of each detected AIOT device (including the AIOT device 202). Thus, the report contains the tuple: (AIOT device ID; reader HRTTD, AIOT qHRTTD).

[0099] In step 13 (613), the LMF 190 dequantizes the qHRTTD, now called the AIOT HRTTD.

[0100] In step 14 (614), the LMF 190 uses the AIOT HRTTD and the reported reader HRTTD, and calculates the propagation delay between the AIOT device 202 and the reader 630 as half of the difference of the above quantities. Then it converts the propagation delay to distance.

[0101] Finally, in step 15 (615), the LMF 190 estimates the location of the AIOT device 202 using the distances to different readers by state-of-the-art location methods.

[0102] Solution 2

[0103] In the case where the AIOT device 202 can only reflect the activation signal, the qHRTTD will be fixed, regardless of the situation, approximately 0 for device A and a constant but known value for device B. In this case, if the type cannot be derived solely from the ID, the AIOT device 202 can abandon Figure 6 Method 3 (603) in, and only reply using its ID and / or type (A or B).

[0104] Even in the case of pure backscattering, the AIoT device 202 reflects the incident wave in a pattern that indicates the ID of the AIoT device 202. For example, the AIoT device 202 can choose to reflect the incoming signal in an on / off manner to encode the ID in binary form. This type of encoding can be considered a form of attaching AIoT device-specific information. For an active AIoT device 202, the ID of the AIoT device 202 can be sent in the following manner (e.g., sent to the reader 630) or attached in such a way that the ID of the AIoT device 202 is carried by the actual payload.

[0105] Solution 3

[0106] This solution describes Figure 6 the behavior of the AIoT 202 shown in box 3 (603).

[0107] Specifically (1 - 8):

[0108] 1. At 604, the AIoT device 202 measures the reception time of the activation signal 602.

[0109] 2. The activation signal 602 is continuously transmitted during the positioning session.

[0110] 3. At 605, the AIoT device 202 selects a time slot for sending the response. A later time slot is called the TX time.

[0111] 4. At 606, the device 202 then calculates the difference between the RX time and the TX time, where this difference is called HRTTD.

[0112] 5. The device 202 normalizes this value to the 5G NR sampling time Ts, i.e.,

[0113]

[0114] 6. At 607, the AIoT device 202 quantizes the HRTTD to a precision with an integer part of B1 bits and a fractional part of B2 bits, as shown in the pre-configuration 601 (fixed or configurable by the implementation at the start of the positioning session):

[0115] qHRTTD = quantize(HRTTD, B1, B2).

[0116] 7. At 608, the AIOT device 202 encodes qHRTTD in its response. a. In one embodiment, if the waveform of the response is OOK, the qHRTTD modulates a bit string. b. In another embodiment, if the response waveform is SC-FDM or OFDM, then (i-ii): i. qHRTTD is modulated according to a QAM constellation, ii. the complex signal is mapped to one or more subcarriers and converted to a sum of sine curves in the time domain.

[0117] 8. At 609, the AIOT device 202 transmits its response (encoded qHRTTD) at the TX instance selected in step 2.

[0118] Examples (1-6):

[0119] 1. The AIOT device 202 measures RX time = 6.5Ts, where Ts = 32.55 ns.

[0120] 2. The AIOT device 202 selects TX time = 12Ts.

[0121] 3. The device 202 calculates HRTTD = 12TS - 6.5Ts = 5.5Ts.

[0122] 4. Apply normalization, and HRTTD = 5.5.

[0123] 5. The integer part of the normalized HRTTD is quantized to B1 = 7 bits, the fractional part is quantized to B2 = 1 bit, and the result becomes qHRTTD = [0 0 0 0 1 0 1 1].

[0124] 6. Then, qHRTTD is modulated and upconverted to a carrier and transmitted.

[0125] Advantages and technical effects of the examples described herein include AIOT positioning that does not require (e.g., without) synchronizing the AIOT device to the NW, and the AIOT device does not need to explicitly report the RX-TX time difference, thus minimizing reporting overhead.

[0126] The examples described herein are related to ambient IoT Rel.19SI and are thus related to standardized signaling. The estimated reception time of the activation signal of the ambient IoT device described herein can be implemented using ambient IoT devices (such as the device under test (DUT) ambient IoT device), gNB, and UE readers. This implementation connects a communication device (such as a communication tester) acting as a gNB and an SCU for configuration and measurement reporting. The SCU also controls a signal generator capable of generating RF signals for the analog activation signal and decodes the reflected signals from the AIOT device.

[0127] AsFigure 6 The configuration shown describes the system herein. The AIoT device measures the reception time of the activation signal. The AIoT device selects a time slot for sending a response. The AIoT device sends its response (encoded qHRTTD) on the selected TX instance. Based on this response, aspects of Solution 3 can be implemented.

[0128] Figure 7 An example device 700 configured to implement the examples described herein (which may be implemented in hardware). The device 700 includes at least one processor 702 (e.g., FPGA and / or CPU), one or more memories 704 including computer program code 705, the computer program code 705 having instructions for performing the methods described herein, wherein at least one memory 704 and the computer program code 705 are configured to, together with at least one processor 702, cause the device 700 to implement circuitry, processes, components, modules, or functions (implemented by control module 706) to implement the examples described herein. The memory 704 may be non-transitory memory, transitory memory, volatile memory (e.g., RAM), or non-volatile memory (e.g., ROM).

[0129] Localization 730 can implement the examples described herein for AIoT multi-point localization.

[0130] The device 700 includes a display and / or I / O interface 708, which includes user interface (UI) circuitry and elements that can be used to display aspects or states of the methods described herein (e.g., when one of these methods is being executed or at a subsequent time), or to receive input from a user, such as using a keypad, camera, touch screen, touch area, microphone, biometrics, one or more sensors, etc. The device 700 includes one or more communications, e.g., (multiple) network (N / W) interface(s) (I / F) 710. The (multiple) communication I / F 710 can be wired and / or wireless and communicate over the (multiple) Internet / other networks via any communication technology (including via one or more links 724). The (multiple) links 724 can be from Figure 1 the (multiple) links 131 and / or 176. The (multiple) links 131 and / or 176 from Figure 1 can also be implemented using the (multiple) transceivers 716 and the (multiple) corresponding wireless links 726. The (multiple) communication I / F 710 can include one or more transmitters or one or more receivers.

[0131] The transceiver 716 includes one or more transmitters 718 and one or more receivers 720. The transceiver 716 and / or the communication I / F(s) 710 may include standard well-known components such as amplifiers, filters, frequency converters, (de)modulators and encoder / decoder circuitry, and one or more antennas such as antenna 714 for communicating over the wireless link 726.

[0132] The control module 706 of the device 700 includes one or both of components 706-1 and / or 706-2, which can be implemented in a variety of ways. The control module 706 can be implemented in hardware as control module 706-1, such as being implemented as part of one or more processors 702. The control module 706-1 can also be implemented as an integrated circuit or by other hardware such as a programmable gate array. In another example, the control module 706 can be implemented as control module 706-2, which is implemented as computer program code (with corresponding instructions) 705 and executed by one or more processors 702. For example, one or more memories 704 store instructions that, when executed by one or more processors 702, cause the device 700 to perform one or more of the operations described herein. Additionally, one or more processors 702, one or more memories 704, and example algorithms (e.g., as flowcharts and / or signaling diagrams) (encoded as instructions, programs, or code) are components for performing the operations described herein.

[0133] The apparatus 700 for implementing the functions of the control module 706 may be the UE 110, the RAN node 170 (e.g., gNB), or the (multiple) network elements 190 (e.g., LMF 190). Thus, the processor 702 may correspond to the (multiple) processors 120, the (multiple) processors 152, and / or the (multiple) processors 175, the memory 704 may correspond to one or more memories 125, one or more memories 155, and / or one or more memories 171, the computer program code 705 may correspond to the computer program code 123, the computer program code 153, and / or the computer program code 173, the control module 706 may correspond to the module 140-1, the module 140-2, the module 150-1, and / or the module 150-2, and the (multiple) communication I / F 710 and / or the transceiver 716 may correspond to the transceiver 130, the (multiple) antennas 128, the transceiver 160, the (multiple) antennas 158, the (multiple) N / W I / F 161, and / or the (multiple) N / W I / F 180. Alternatively, the apparatus 700 and its elements may not correspond to any of the UE 110, the RAN node 170, or the (multiple) network elements 190 and their corresponding elements, because the apparatus 700 may be part of a self-organizing / optimizing network (SON) node or other node (such as a node in the cloud).

[0134] The apparatus 700 may also correspond to the environmental IoT device 202, the intermediate node 304, the auxiliary node 406, the activator 620, or the reader 630.

[0135] The apparatus 700 may also be distributed throughout the network (e.g., 100), including inside and between the apparatus 700 and any network element (such as the network control element (NCE) 190 and / or the RAN node 170 and / or the UE 110).

[0136] The interface 712 enables data communication and signaling between various items of the apparatus 700, such as Figure 7As shown. For example, interface 712 can be one or more buses, such as an address, data, or control bus, and can include any interconnection mechanism, such as a series of lines on a motherboard or integrated circuit, optical fibers, or other optical communication devices, etc. The computer program code (e.g., instructions) 705 including control module 706 can include object-oriented software configured to transfer data or messages between objects within the computer program code 705, or the computer program code (e.g., instructions) 705 including control module 706 can include function, script, or procedure code. Device 700 does not need to include every feature mentioned, or can also include other features. Various components of device 700 can be at least partially located in a common housing 728, or a subset of various components of device 700 can be at least partially located in different housings, which can include housing 728.

[0137] Figure 8 A schematic diagram shows non-volatile memory media 800a (e.g., computer / optical disc (CD) or digital versatile disc (DVD)) and 800b (e.g., universal serial bus (USB) memory stick) and 800c (e.g., cloud storage for downloading instructions and / or parameters 802 or receiving email instructions and / or parameters 802) storing instructions and / or parameters 802, which, when executed by a processor, allow the processor to execute one or more steps of the methods described herein. The instructions and / or parameters 802 can represent a non-transitory computer-readable medium.

[0138] Figure 9 is an example method 900 based on the example embodiments described herein. At 910, the method includes sending a configuration associated with the received transmission time difference to a first device or a second device. At 920, the method includes where the configuration includes at least one of the following: information for determining the received transmission time difference, or a request to determine the received transmission time difference. At 930, the method includes receiving a report associated with the received transmission time difference from the second device. Method 900 can be executed using one or more network elements 190 (e.g., LMF 190) or device 700.

[0139] Figure 10 is an example method 1000 based on the example embodiments described herein. At 1010, the method includes receiving a configuration associated with the received transmission time difference. At 1020, the method includes where the configuration includes at least one of the following: information for determining the received transmission time difference, or a request to determine the received transmission time difference. At 1030, the method includes determining the received transmission time difference. At 1040, the method includes sending a response including the determined received transmission time difference to a device. Method 1000 can be executed using AIoT device 202 or device 700.

[0140] Figure 11 is an example method 1100 based on the example embodiments described herein. At 1110, the method includes receiving a configuration associated with a received transmission time difference from a network entity. At 1120, the method includes where the configuration includes at least one of the following: information for determining the received transmission time difference, or a request to determine the received transmission time difference. At 1130, the method includes determining the received transmission time difference. At 1140, the method includes sending a report associated with the determined received transmission time difference to the network entity. Method 1100 can be executed using reader 630 or device 700.

[0141] Figure 12 is an example method 1200 based on the example embodiments described herein. At 1210, the method includes receiving a configuration for multi-hop positioning, where the configuration includes an indication to send an activation signal. At 1220, the method includes sending an activation signal to a first device. At 1230, the method includes where the activation signal is configured to determine a first device received transmission time difference associated with the first device and a second device received transmission time difference associated with a second device. Method 1200 can be executed using activator 620 or device 700.

[0142] Figure 13 is an example method 1300 based on the example embodiments described herein. At 1310, the method includes receiving information from a device, the information including at least one of the following: an identifier of the device, or a type of the device. At 1320, the method includes determining the type of the device. At 1330, the method includes where the type of the device is determined according to the identifier of the device, or the type of the device is determined according to the information including the type of the device. At 1340, the method includes determining a received transmission time difference associated with the device based on the type of the device. Method 1300 can be executed using one or more network elements 190 (e.g., LMF 190), reader 630 or device 700.

[0143] Figure 14is an example method 1400 based on the example embodiments described herein. At 1410, the method includes receiving an activation signal. At 1420, the method includes sending information to a network entity, the information including at least one of: an identifier of the device, or a type of the device. At 1430, the method includes sending, in response to the activation signal triggering a response, information including at least one of the identifier of the device or the type of the device to the network entity. At 1440, the method includes where the type of the device includes the device is a passive device without energy storage, or the type of the device includes the device is a passive device with energy storage. Method 1400 may be performed using the AIoT device 202 or the device 700.

[0144] Figure 15 is an example method 1500 based on the example embodiments described herein. At 1510, the method includes measuring a reception time of an activation signal triggering a response. At 1520, the method includes determining a transmission time of the response. At 1530, the method includes determining a reception transmission time difference as a difference between the transmission time of the response and the reception time of the activation signal triggering the response. Method 1500 may be performed using the AIoT device 202 or the device 700.

[0145] The following examples are provided and described herein.

[0146] Example 1. A device, comprising: components for sending a configuration associated with a reception transmission time difference to a first device or a second device; where the configuration includes at least one of: information for determining the reception transmission time difference, or a request for determining the reception transmission time difference; and components for receiving a report associated with the reception transmission time difference from the second device.

[0147] Example 2. The device according to Example 1, where: the first device includes an Ambient Internet of Things (AIoT) device, or the AIoT device includes the first device, or the second device includes a reader, or the reader includes the second device, or the device includes a Location Management Function (LMF).

[0148] Example 3. The device according to any one of Examples 1 to 2, where: when the report associated with the determined reception transmission time difference is received based on an activation signal sent from a gNB, or at least one of the second device resides within the gNB, the report associated with the determined reception transmission time difference is received from the second device within an information element (IE) of a Long-Term Evolution Positioning Protocol (LPP) provide location information message, or the report associated with the determined reception transmission time difference is received from the second device via a New Radio Positioning Protocol A (NRPPa) interface.

[0149] Example 4. The apparatus according to any one of Examples 1 to 3, wherein the configuration associated with the received transmission time difference is sent within an information element (IE) of a Long Term Evolution Positioning Protocol (LPP) request location information message.

[0150] Example 5. The apparatus according to any one of Examples 1 to 4, wherein the report associated with the determined received transmission time difference includes at least one of the following: information related to a first device received transmission time difference associated with the first device, or information related to a second device received transmission time difference associated with the second device.

[0151] Example 6. The apparatus according to Example 5, further comprising: components for determining the first device received transmission time difference based on the information related to the first device received transmission time difference.

[0152] Example 7. The apparatus according to any one of Examples 5 to 6, further comprising: components for determining a propagation delay between the first device and the second device based on the first device received transmission time difference and the second device received transmission time difference; components for determining a distance between the first device and the second device based on the propagation delay; and components for determining a position of the first device based on the distance between the first device and the second device.

[0153] Example 8. The apparatus according to Example 7, further comprising: components for determining the propagation delay based on a difference between the first device received transmission time difference and the second device received transmission time difference.

[0154] Example 9. The apparatus according to any one of Examples 7 to 8, further comprising: components for determining a distance between the first device and at least one other device based on a propagation delay between the first device and the at least one other device; and components for determining the position of the first device based on the distance between the first device and the at least one other device.

[0155] Example 10. The apparatus according to any one of Examples 5 to 9 further comprises: means for sending to the first device a request for determining the reception transmission time difference of the first device; wherein the request for determining the reception transmission time difference of the first device includes an indication of the number of bits for the integer part of the transmission time difference received by the first device; wherein the request for determining the reception transmission time difference of the first device includes an indication of the number of bits for the fractional part of the transmission time difference received by the first device; and wherein the information related to the reception transmission time difference of the first device received from the second device is based on the number of bits for the integer part of the transmission time difference received by the first device and the number of bits for the fractional part of the transmission time difference received by the first device.

[0156] Example 11. The apparatus according to any one of Examples 1 to 10 further comprises: means for sending to the first device an identifier of the second device; and means for sending to the second device an identifier of the first device.

[0157] Example 12. An apparatus comprises: means for receiving a configuration associated with a reception transmission time difference; wherein the configuration includes at least one of the following: information for determining the reception transmission time difference, or a request for determining the reception transmission time difference; means for determining the reception transmission time difference; and means for sending to a device a response including the determined reception transmission time difference.

[0158] Example 13. The apparatus according to Example 12 further comprises: means for determining the reception transmission time difference as the difference between the transmission time of the response and the reception time of an activation signal triggering the response.

[0159] Example 14. In the apparatus according to Example 13, the transmission time of the response includes one or more of the following: a delay related to charging the apparatus, or a delay related to switching from a receiver chain of the apparatus to a transmission chain of the apparatus.

[0160] Example 15. The apparatus according to any one of Examples 12 to 14 further comprises: means for approximating the reception transmission time difference to generate an approximated reception transmission time difference; and means for sending to the device a response including the approximated reception transmission time difference.

[0161] Example 16. The apparatus according to Example 15 further comprises: components for receiving, within the request for determining the received transmission time difference, an indication of the number of bits for the integer part of the approximate received transmission time difference; components for receiving, within the request for determining the received transmission time difference, an indication of the number of bits for the fractional part of the approximate received transmission time difference; and components for approximating the received transmission time difference based on the number of bits for the integer part of the approximate received transmission time difference and the number of bits for the fractional part of the approximate received transmission time difference.

[0162] Example 17. The apparatus according to any one of Examples 15 to 16, wherein approximating the received transmission time difference to generate the approximate received transmission time difference comprises: quantizing the received transmission time difference to generate a quantized received transmission time difference, the quantized received transmission time difference being an approximation of the received transmission time difference.

[0163] Example 18. An apparatus comprises: components for receiving, from a network entity, a configuration associated with a received transmission time difference; wherein the configuration comprises at least one of the following: information for determining the received transmission time difference, or a request for determining the received transmission time difference; components for determining the received transmission time difference; and components for sending, to the network entity, a report associated with the determined received transmission time difference.

[0164] Example 19. The apparatus according to Example 18 further comprises: components for receiving an acknowledgement from a device; components for determining the received transmission time difference as the difference between the transmission time of an activation signal that triggers the acknowledgement and the reception time of the acknowledgement; and components for sending, to the network entity, the report comprising the received transmission time difference associated with the apparatus and an approximate received transmission time difference associated with the device.

[0165] Example 20. The apparatus according to Example 19 further comprises: components for receiving the acknowledgement from the device, wherein the acknowledgement comprises the approximate received transmission time difference associated with the device; and components for reconstructing the approximate received transmission time difference based on waveform characteristics of the acknowledgement received from the device.

[0166] Example 21. The apparatus according to any one of Examples 19 to 20 further comprises: components for receiving the activation signal when the apparatus is within the coverage area of the activation signal; and components for canceling the activation signal in response to an overlap between the activation signal and the acknowledgement received from the device.

[0167] Example 22. The apparatus according to any one of Examples 19 to 21 further comprises: a component for sending an identifier of the device to the network entity in the report.

[0168] Example 23. The apparatus according to any one of Examples 19 to 22 further comprises: a component for receiving an identifier of the device from the device in the response received from the device.

[0169] Example 24. An apparatus comprising: a component for receiving a configuration for multi-hop positioning, wherein the configuration includes an indication of sending an activation signal; and a component for sending the activation signal to a first device; wherein the activation signal is configured to determine a first device receive transmission time difference associated with the first device and a second device receive transmission time difference associated with a second device.

[0170] Example 25. The apparatus according to Example 24, wherein: the first device receive transmission time difference includes a difference between a transmission time of a response from the first device and a reception time of the activation signal that triggers the response; and the second device receive transmission time difference includes a difference between a transmission time of the activation signal that triggers the response and a reception time of the response from the first device; wherein the apparatus includes an activator, or the activator includes the apparatus.

[0171] Example 26. A method comprising: sending a configuration associated with a receive transmission time difference to a first device or a second device; wherein the configuration includes at least one of the following: information for determining the receive transmission time difference, or a request for determining the receive transmission time difference; and receiving a report associated with the receive transmission time difference from the second device.

[0172] Example 27. A method comprising: receiving a configuration associated with a receive transmission time difference; wherein the configuration includes at least one of the following: information for determining the receive transmission time difference, or a request for determining the receive transmission time difference; determining the receive transmission time difference; and sending a response including the determined receive transmission time difference to a device.

[0173] Example 28. A method comprising: receiving a configuration associated with a receive transmission time difference from a network entity; wherein the configuration includes at least one of the following: information for determining the receive transmission time difference, or a request for determining the receive transmission time difference; determining the receive transmission time difference; and sending a report associated with the determined receive transmission time difference to the network entity.

[0174] Example 29. A method includes: receiving a configuration for multi-hop positioning, where the configuration includes an indication of sending an activation signal; and sending the activation signal to a first device; where the activation signal is configured to determine a first device receive transmission time difference associated with the first device and a second device receive transmission time difference associated with a second device.

[0175] Example 30. A device includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: send a configuration associated with receive transmission time difference to a first device or a second device; where the configuration includes at least one of the following: information for determining the receive transmission time difference, or a request for determining the receive transmission time difference; and receive a report associated with the receive transmission time difference from the second device.

[0176] Example 31. A device includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: receive a configuration associated with receive transmission time difference; where the configuration includes at least one of the following: information for determining the receive transmission time difference, or a request for determining the receive transmission time difference; determine the receive transmission time difference; and send a response including the determined receive transmission time difference to a device.

[0177] Example 32. A device includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: receive a configuration associated with receive transmission time difference from a network entity; where the configuration includes at least one of the following: information for determining the receive transmission time difference, or a request for determining the receive transmission time difference; determine the receive transmission time difference; and send a report associated with the determined receive transmission time difference to the network entity.

[0178] Example 33. A device includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: receive a configuration for multi-hop positioning, where the configuration includes an indication of sending an activation signal; and send the activation signal to a first device; where the activation signal is configured to determine a first device receive transmission time difference associated with the first device and a second device receive transmission time difference associated with a second device.

[0179] Example 34. A computer-readable medium comprising instructions stored thereon for at least performing the following: sending a configuration associated with a received transmission time difference to a first device or a second device; wherein the configuration comprises at least one of the following: information for determining the received transmission time difference, or a request for determining the received transmission time difference; and receiving a report associated with the received transmission time difference from the second device.

[0180] Example 35. A computer-readable medium comprising instructions stored thereon for at least performing the following: receiving a configuration associated with a received transmission time difference; wherein the configuration comprises at least one of the following: information for determining the received transmission time difference, or a request for determining the received transmission time difference; determining the received transmission time difference; and sending a response comprising the determined received transmission time difference to a device.

[0181] Example 36. A computer-readable medium comprising instructions stored thereon for at least performing the following: receiving a configuration associated with a received transmission time difference from a network entity; wherein the configuration comprises at least one of the following: information for determining the received transmission time difference, or a request for determining the received transmission time difference; determining the received transmission time difference; and sending a report associated with the determined received transmission time difference to the network entity.

[0182] Example 37. A computer-readable medium comprising instructions stored thereon for at least performing the following: receiving a configuration for multi-hop positioning, wherein the configuration comprises an indication of sending an activation signal; and sending the activation signal to a first device; wherein the activation signal is configured to determine a first device received transmission time difference associated with the first device and a second device received transmission time difference associated with a second device.

[0183] Example 38. A device comprising: means for receiving information from a device, the information comprising at least one of the following: an identifier of the device, or a type of the device; means for determining the type of the device; wherein the type of the device is determined based on the identifier of the device, or the type of the device is determined based on the information comprising the type of the device; and means for determining a received transmission time difference associated with the device based on the type of the device.

[0184] Example 39. The device according to Example 38, wherein the means for receiving the information comprises means for receiving a response to an activation signal for conveying the information.

[0185] Example 40. The apparatus of Example 39 further comprises: a component for determining a pattern of the response to the activation signal; and a component for determining at least one of the identifier of the device or the type of the device based on the pattern of the response to the activation signal.

[0186] Example 41. An apparatus according to any one of Examples 39 to 40, wherein: the response to the activation signal is received in a known pattern; and the component for determining at least one of the identifier of the device or the type of the device based on the pattern includes: a component for inferring at least one of the identifier of the device or the type of the device from the known pattern.

[0187] Example 42. The apparatus of any one of Examples 38 to 41, further comprising means for sending a report to a network element, the report including the determined receive-transmit time difference associated with the device.

[0188] Example 43. The apparatus of Example 42, wherein the report is sent within an information element (IE) of a Long Term Evolution Positioning Protocol (LPP) Provide Location Information message.

[0189] Example 44. An apparatus according to any one of Examples 42 to 43, wherein the report is sent using a New Radio Positioning Protocol A (NRPPa) interface in response to at least one of the following: the information including at least one of the identifier of the device or the type of the device is received based on an activation signal sent from a gNB, or the apparatus resides within a gNB.

[0190] Example 45. The apparatus of any one of Examples 42 to 44, wherein the network element comprises a location management function (LMF).

[0191] Example 46. The apparatus of any one of Examples 38 to 45, further comprising a component for determining the type of the device based on the identifier of the device.

[0192] Example 47. An apparatus according to any one of Examples 38 to 46, further comprising: a component for determining the receive-transmit time difference associated with the device to be substantially equal to zero in response to determining that the type of the device is a passive device without energy storage; and a component for determining the receive-transmit time difference associated with the device to be a known value in response to determining that the type of the device is a passive device with energy storage.

[0193] Example 48. The apparatus according to any one of Examples 38 to 47, wherein: when the type of the device includes that the device is a passive device without energy storage, the type of the device is A; and when the type of the device includes that the device is a passive device with energy storage, the type of the apparatus is B.

[0194] Example 49. The apparatus according to any one of Examples 38 to 48, further comprising: a component for receiving a response to an activation signal from the device, the response including a reflection of the activation signal that triggered the response; wherein the response to the activation signal that triggered the response includes: the information including at least one of the identifier of the device or the type of the device.

[0195] Example 50. The apparatus according to any one of Examples 38 to 49, wherein: the device includes an ambient Internet of Things (AIoT) device, or the ambient Internet of Things (AIoT) device includes the device, or the device includes a reader, or the reader includes the device.

[0196] Example 51. The apparatus according to any one of Examples 38 to 50, wherein: the apparatus includes a reader, or the reader includes the apparatus, or the apparatus includes a Location Management Function (LMF).

[0197] Example 52. An apparatus, comprising: a component for receiving an activation signal; and a component for sending information to a network entity, the information including at least one of: the identifier of the apparatus, or the type of the apparatus; wherein the information including at least one of the identifier of the apparatus or the type of the apparatus is sent to the network entity in a response to the activation signal that triggers a response; wherein the type of the apparatus includes that the apparatus is a passive device without energy storage, or the type of the apparatus includes that the apparatus is a passive device with energy storage.

[0198] Example 53. The apparatus according to Example 52, further comprising: a component for sending the response to the activation signal to the network entity as a reflection of the activation signal, the mode of the response to the activation signal indicating at least one of the identifier of the apparatus or the type of the apparatus.

[0199] Example 54. The apparatus according to any one of Examples 52 to 53, wherein the type of the apparatus is configured to determine a received transmission time difference associated with the apparatus.

[0200] Example 55. The apparatus according to any one of Examples 52 to 54, wherein the identifier of the apparatus indicates the type of the apparatus.

[0201] Example 56. The apparatus according to any one of Examples 52 to 55, wherein: when the type of the apparatus includes that the apparatus is a passive device without energy storage, the type of the apparatus is A; and when the type of the apparatus includes that the apparatus is a passive device with energy storage, the type of the apparatus is B.

[0202] Example 57. The apparatus according to any one of Examples 52 to 56, wherein when the type of the apparatus includes that the apparatus is a passive device without energy storage, the reception transmission time difference associated with the apparatus is substantially equal to zero.

[0203] Example 58. The apparatus according to any one of Examples 52 to 57, wherein when the type of the apparatus includes that the apparatus is a passive device with energy storage, the reception transmission time difference associated with the apparatus is a known value.

[0204] Example 59. The apparatus according to any one of Examples 52 to 58, further comprising: components for encoding at least one of the identifier of the apparatus or the type of the apparatus in a known pattern and sending the response to the activation signal to the network entity in the known pattern.

[0205] Example 60. The apparatus according to any one of Examples 52 to 59, wherein: the apparatus includes an ambient Internet of Things (AIoT) device, or the ambient Internet of Things (AIoT) device includes the apparatus.

[0206] Example 61. The apparatus according to any one of Examples 52 to 60, wherein: the network entity includes a reader, or the reader includes the network entity.

[0207] Example 62. The apparatus according to any one of Examples 52 to 61, wherein the activation signal is received from an activator.

[0208] Example 63. A method, comprising: receiving information from a device, the information including at least one of the following: an identifier of the device, or a type of the device; determining the type of the device; wherein the type of the device is determined according to the identifier of the device, or the type of the device is determined according to the information including the type of the device; and determining a reception transmission time difference associated with the device based on the type of the device.

[0209] Example 64. A method includes: receiving an activation signal; and sending information to a network entity, the information including at least one of the following: an identifier of the device, or a type of the device; wherein the information including at least one of the identifier of the device or the type of the device is sent to the network entity in response to the activation signal that triggers a response; wherein the type of the device includes that the device is a passive device without energy storage, or the type of the device includes that the device is a passive device with energy storage.

[0210] Example 65. A device includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: receive information from a device, the information including at least one of the following: an identifier of the device, or a type of the device; determine the type of the device; wherein the type of the device is determined based on the identifier of the device, or the type of the device is determined based on the information including the type of the device; and determine a receive transmit time difference associated with the device based on the type of the device.

[0211] Example 66. A device includes: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the device to at least: receive an activation signal; and send information to a network entity, the information including at least one of the following: an identifier of the device, or a type of the device; wherein the information including at least one of the identifier of the device or the type of the device is sent to the network entity in response to the activation signal that triggers a response; wherein the type of the device includes that the device is a passive device without energy storage, or the type of the device includes that the device is a passive device with energy storage.

[0212] Example 67. A computer-readable medium includes instructions stored thereon for at least performing the following: receiving information from a device, the information including at least one of the following: an identifier of the device, or a type of the device; determining the type of the device; wherein the type of the device is determined based on the identifier of the device, or the type of the device is determined based on the information including the type of the device; and determining a receive transmit time difference associated with the device based on the type of the device.

[0213] Example 68. A computer-readable medium includes instructions stored thereon for at least performing the following: receiving an activation signal; and sending information to a network entity, the information including at least one of the following: an identifier of the device, or the type of the device; wherein the information including at least one of the identifier of the device or the type of the device is sent to the network entity in response to the activation signal that triggers the response; wherein the type of the device includes that the device is a passive device without energy storage, or the type of the device includes that the device is a passive device with energy storage.

[0214] Example 69. A device includes: components for measuring the reception time of an activation signal that triggers a response; components for determining the transmission time of the response; and components for determining the reception-transmission time difference as the difference between the transmission time of the response and the reception time of the activation signal that triggers the response.

[0215] Example 70. The device according to Example 69, wherein the activation signal is continuously received during a positioning session.

[0216] Example 71. The device according to any one of Examples 69 to 70 further includes: components for determining the reception-transmission time difference as the determined reception-transmission time difference divided by a sampling time.

[0217] Example 72. The device according to Example 71, wherein the sampling time includes a fifth-generation new radio sampling time.

[0218] Example 73. The device according to any one of Examples 69 to 72 further includes: components for approximating the reception-transmission time difference to generate an approximated reception-transmission time difference.

[0219] Example 74. The approximating the reception-transmission time difference to generate the approximated reception-transmission time difference includes: quantifying the reception-transmission time difference to generate a quantized reception-transmission time difference, the quantized reception-transmission time difference being an approximation of the reception-transmission time difference.

[0220] Example 75. The device according to any one of Examples 73 to 74 further includes: components for approximating the reception-transmission time difference to generate the approximated reception-transmission time difference by using the number of bits for the integer part of the approximated reception-transmission time difference.

[0221] Example 76. The device according to Example 75 further includes: components for determining an indication of the number of bits for the integer part of the approximated reception-transmission time difference based on a configuration.

[0222] Example 77. The apparatus according to Example 76, further comprising: a component for receiving the configuration from a location management function.

[0223] Example 78. The apparatus according to any one of Examples 76 to 77, further comprising: a component for determining the configuration based on the implementation of the apparatus.

[0224] Example 79. The apparatus according to any one of Examples 73 to 78, further comprising: a component for approximating the received transmission time difference using the number of bits for the fractional part of the approximated received transmission time difference to generate the approximated received transmission time difference.

[0225] Example 80. The apparatus according to Example 79, further comprising: a component for determining an indication of the number of bits for the fractional part of the approximated received transmission time difference based on a configuration.

[0226] Example 81. The apparatus according to Example 80, further comprising: a component for receiving the configuration from a location management function.

[0227] Example 82. The apparatus according to any one of Examples 80 to 81, further comprising: a component for determining the configuration based on the implementation of the apparatus.

[0228] Example 83. The apparatus according to any one of Examples 73 to 82, further comprising: a component for encoding the approximated received transmission time difference within the response.

[0229] Example 84. The apparatus according to Example 83, further comprising: a component for transmitting the response including the encoded approximated received transmission time difference to a reader at a selected transmission time of the response.

[0230] Example 85. The apparatus according to any one of Examples 73 to 84, further comprising: a component for modulating the approximated received transmission time difference based on the bits for the approximated received transmission time difference when the waveform of the response is based on on - off keying.

[0231] Example 86. In the apparatus according to Example 85, the bits for the approximated received transmission time difference include bits for the integer part of the approximated received transmission time difference.

[0232] Example 87. In the apparatus according to any one of Examples 85 to 86, the bits for the approximated received transmission time difference include bits for the fractional part of the approximated received transmission time difference.

[0233] Example 88. The apparatus according to any one of Examples 73 to 87 further comprises: components for modulating the approximate received transmission time difference based on an orthogonal amplitude modulation constellation when the waveform of the response is based on single-carrier frequency division multiplexing.

[0234] Example 89. The apparatus according to any one of Examples 73 to 88 further comprises: components for modulating the approximate received transmission time difference based on an orthogonal amplitude modulation constellation when the waveform of the response is based on orthogonal frequency division multiplexing.

[0235] Example 90. The apparatus according to any one of Examples 73 to 89 further comprises: components for mapping the approximate received transmission time difference to one or more subcarriers.

[0236] Example 91. The apparatus according to any one of Examples 73 to 90 further comprises: components for converting the approximate received transmission time difference into a sum of time domains of sine curves.

[0237] Example 92. The apparatus according to any one of Examples 69 to 91, wherein the apparatus comprises an ambient Internet of Things device.

[0238] Example 93. The apparatus according to any one of Examples 69 to 92, wherein the ambient Internet of Things device comprises the apparatus.

[0239] Example 94. A method comprising: measuring the reception time of an activation signal that triggers a response; determining the transmission time of the response; and determining the received transmission time difference as the difference between the transmission time of the response and the reception time of the activation signal that triggers the response.

[0240] Example 95. A device comprising: at least one processor; and at least one memory storing instructions which, when executed by the at least one processor, cause the device to at least: measure the reception time of an activation signal that triggers a response; determine the transmission time of the response; and determine the received transmission time difference as the difference between the transmission time of the response and the reception time of the activation signal that triggers the response.

[0241] Example 96. A computer-readable medium comprising instructions stored thereon for at least performing the following: measuring the reception time of an activation signal that triggers a response; determining the transmission time of the response; and determining the received transmission time difference as the difference between the transmission time of the response and the reception time of the activation signal that triggers the response.

[0242] References to "computers", "processors", etc., should be understood to cover not only computers with different architectures, such as single / multiprocessor architectures and sequential or parallel architectures, but also dedicated circuits, such as field programmable gate arrays (FPGAs), application specific circuits (ASICs), signal processing devices, and other processing circuitry. References to computer programs, instructions, code, etc., should be understood to cover software or firmware for programmable processors, such as, for example, the programmable content of a hardware device, whether instructions for a processor or configuration settings for a fixed function device, gate array, or programmable logic device, etc.

[0243] The memories described herein 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, non-transitory memory, transitory memory, fixed memory, and removable memory. The memory can include a database for storing data.

[0244] As used herein, the term "circuitry" can refer to the following: (a) a hardware circuit implementation, such as an implementation in analog and / or digital circuitry, and (b) a combination of circuits and software (and / or firmware), such as, as applicable: (i) a combination of (one or more) processors, or (ii) portions of (one or more) processors / software, including (one or more) digital signal processors, software, and memory, which work together to enable a device to perform various functions, and (c) a circuit that requires software or firmware to operate (even if the software or firmware is not physically present), such as (one or more) microprocessors or portions of (one or more) microprocessors. As another example, as used herein, the term "circuitry" will also cover an implementation that includes only one processor (or more than one processor) or a portion of a processor and its attendant software and / or firmware. For example, if applicable to a particular element, the term "circuitry" will also cover a baseband integrated circuit or an application processor integrated circuit for a mobile phone, or a similar integrated circuit in a server, a cellular network device, or another network device.

[0245] It should be understood that the above description is illustrative only. Those skilled in the art can design various alternatives and modifications. For example, the features recited in the various dependent claims can be combined with each other in any suitable combination. In addition, the features of the above different example embodiments can be selectively combined into new example embodiments. Accordingly, this specification is intended to cover all such alternatives, modifications, and variations that fall within the scope of the appended claims.

[0246] The following abbreviations and acronyms may appear in the specification and / or drawings (the abbreviations and acronyms may be attached / combined with other characters using, for example, dashes, hyphens, slashes, letters, or numbers, and may be case-insensitive):

[0247] 3GPP: The Third Generation Partnership Project

[0248] 4G: The Fourth Generation

[0249] 5G: The Fifth Generation

[0250] 5GC: 5G Core Network

[0251] AMF: Access and Mobility Management Function

[0252] AIOT: Ambient Internet of Things

[0253] ASIC: Application Specific Integrated Circuit

[0254] B1: The number of bits dedicated to quantizing the integer part of the hybrid receive transmission time difference. B2: The number of bits dedicated to quantizing the fractional part of the hybrid receive transmission time difference. BS: Base Station

[0255] CD: Compact Disc / Computer Disc

[0256] CN: Core Network

[0257] CPU: Central Processing Unit

[0258] CU: Central Unit or Centralized Unit

[0259] DL: Downlink

[0260] DRX: Discontinuous Reception

[0261] DSP: Digital Signal Processor

[0262] DU: Distributed Unit

[0263] DUT: Device Under Test

[0264] DVD: Digital Versatile Disc

[0265] eMTC: Enhanced Machine Type Communication

[0266] eNB: Evolved Node B (e.g., LTE base station)

[0267] EN-DC: E-UTRAN New Radio - Dual Connectivity

[0268] en-gNB: A node that provides termination of the NR user plane and control plane protocols towards the UE and acts as a secondary node in EN-DC

[0269] E-UTRA: Evolved UMTS Terrestrial Radio Access, i.e., LTE radio access technology

[0270] E-UTRAN: E-UTRA Network

[0271] F1: Interface between CU and DU

[0272] FDD: Frequency Division Duplexing

[0273] FPGA: Field Programmable Gate Array

[0274] FS: Feasibility Study

[0275] gNB: Base station for 5G / NR, i.e., a node that provides NR user plane and control plane protocol termination towards the UE and is connected to the 5GC via the NG interface HRTTD: Hybrid Receive Transmission Time Difference

[0276] IAB: Integrated Access and Backhaul

[0277] ID: Identifier

[0278] IE: Information Element

[0279] IEEE: Institute of Electrical and Electronics Engineers

[0280] I / F: Interface

[0281] I / O: Input / Output

[0282] IoT: Internet of Things

[0283] LMF: Location Management Function

[0284] LORA, LoRa: Remote or standardized communication protocol of the International Telecommunication Union

[0285] LPP: LTE Positioning Protocol

[0286] LS: Liaison Statement

[0287] LTE: Long Term Evolution (4G)

[0288] MAC: Media Access Control

[0289] MME: Mobility Management Entity

[0290] MRO: Mobility Robustness Optimization

[0291] NB-IoT: Narrowband Internet of Things

[0292] NCE: Network Control Element

[0293] ng or NG: New Generation

[0294] ng-eNB: New Generation eNB NG-RAN: New Generation Radio Access Network

[0295] NR: New Radio

[0296] NRPPa: NR Positioning Protocol A

[0297] N / W: Network

[0298] NW: Network

[0299] OFDM: Orthogonal Frequency Division Multiplexing

[0300] OOK: On-Off Keying

[0301] PDA: Personal Digital Assistant

[0302] PDCP: Packet Data Convergence Protocol

[0303] PHY: Physical Layer

[0304] QAM: Quadrature Amplitude Modulation

[0305] qHRTTD: Quantized Hybrid Receive Transmission Time Difference

[0306] R: Release (e.g., R18)

[0307] RAM: Random Access Memory

[0308] RAN: Radio Access Network

[0309] RAN#: RAN Meeting or Document

[0310] RedCap: Reduced Capability

[0311] Rel: Release

[0312] RF: Radio Frequency

[0313] RFID: Radio Frequency Identification or Identifier

[0314] RLC: Radio Link Control

[0315] ROM: Read Only Memory

[0316] RP: RAN Plenary

[0317] RRC: Radio Resource Control

[0318] RTT: Round-Trip Time

[0319] RU: Radio Unit

[0320] Rx, RX: Receive or Receiver or Reception SA: Standalone

[0321] SA1: System Aspects Working Group 1

[0322] SC-FDM: Single Carrier Frequency Division Multiplexing

[0323] SCU: Session Control Unit

[0324] SDAP: Service Data Adaptation Protocol

[0325] SGW: Serving Gateway

[0326] SI: Study Item

[0327] SMF: Session Management Function

[0328] SON: Self-Organizing / Optimizing Network

[0329] TDD: Time Division Duplex

[0330] TR: Technical Report

[0331] TRP: Transmission and Reception Point

[0332] TS: Technical Specification

[0333] Tx, TX: Transmit or Transmitter or Transmission

[0334] UAV: Unmanned Aerial Vehicle

[0335] UE: User Equipment (e.g., wireless device, typically a mobile device)

[0336] UHF: Ultra High Frequency

[0337] UI: User Interface

[0338] UMTS: Universal Mobile Telecommunications System

[0339] UPF: User Plane Function

[0340] USB: Universal Serial Bus

[0341] UTRAN: UMTS Terrestrial Radio Access Network

[0342] UWB: Ultra Wide Band

[0343] WG: Working Group

[0344] Wi-Fi: Wireless network protocol family based on the IEEE 802.11 standard family

[0345] X2: Network interface between RAN nodes and between RAN and core network

[0346] Xn: Network interface between NG-RAN nodes.

Claims

1. A device for communication, comprising: means for measuring the time of receipt of an activation signal triggering a response; means for determining a transmission time of said response; as well as Means for determining a reception transmission time difference as a difference between the transmission time of the acknowledgement and the reception time of the activation signal triggering the acknowledgement. The apparatus of claim 1 , wherein the activation signal is received continuously during a positioning session.

3. The device according to any one of claims 1 to 2, further comprising: means for determining the reception transmission time difference as the determined reception transmission time difference divided by a sampling time. The apparatus of claim 3 , wherein the sampling time comprises a fifth generation new radio sampling time.

5. The device according to any one of claims 1 to 4, further comprising: means for approximating the received transmission time difference to generate an approximate received transmission time difference.

6. The apparatus of claim 5 , wherein the approximating the received transmission time difference to generate the approximate received transmission time difference comprises: The received transmission time difference is quantized to generate a quantized received transmission time difference, the quantized received transmission time difference being an approximation of the received transmission time difference.

7. The device according to any one of claims 5 to 6, further comprising: means for approximating the received transmission time difference using the number of bits used for the integer portion of the approximate received transmission time difference to generate the approximate received transmission time difference.

8. The apparatus according to claim 7, further comprising: Means for determining an indication of the number of bits used for the integer portion of the approximate received transmission time difference based on a configuration.

9. The apparatus according to claim 8, further comprising: Means for receiving said configuration from a location management function.

10. The device according to any one of claims 8 to 9, further comprising: Means for determining the configuration based on an implementation of the apparatus.

11. The apparatus according to any one of claims 5 to 10, further comprising: means for approximating the received transmission time difference using a number of bits for a fractional portion of the approximate received transmission time difference to generate the approximate received transmission time difference.

12. The apparatus according to claim 11, further comprising: Means for determining an indication of the number of bits used for the fractional portion of the approximate received transmission time difference based on a configuration.

13. The apparatus according to claim 12, further comprising: Means for receiving said configuration from a location management function.

14. The apparatus according to any one of claims 12 to 13, further comprising: Means for determining the configuration based on an implementation of the apparatus.

15. The apparatus according to any one of claims 5 to 14, further comprising: Means for encoding said approximate receive-transmit time difference within said reply.

16. The apparatus according to claim 15, further comprising: means for transmitting said reply including said encoded approximate receive-transmit time difference to a reader at a selected transmission time of said reply.

17. The apparatus according to any one of claims 5 to 16, further comprising: means for modulating the approximate received transmit time difference based on bits for the approximate received transmit time difference when the waveform of the reply is based on on-off keying.

18. The apparatus of claim 17, wherein the bits used for the approximate received transmit time difference comprise bits for an integer portion of the approximate received transmit time difference.

19. The apparatus of any one of claims 17 to 18, wherein the bits used for the approximate received transmit time difference include bits for a fractional portion of the approximate received transmit time difference.

20. The apparatus according to any one of claims 5 to 19, further comprising: means for modulating the approximate received transmission time difference based on a quadrature amplitude modulation constellation when the waveform of the reply is based on single carrier frequency division multiplexing.

21. The apparatus according to any one of claims 5 to 20, further comprising: means for modulating the approximate receive transmission time difference based on a quadrature amplitude modulation constellation when the waveform of the reply is based on orthogonal frequency division multiplexing.

22. The apparatus according to any one of claims 5 to 21, further comprising: Means for mapping the approximate receive-transmit time difference to one or more subcarriers.

23. The apparatus according to any one of claims 5 to 22, further comprising: means for converting said approximate receive-transmit time difference into a time-domain sum of sinusoids.

24. The apparatus of any one of claims 1 to 23, wherein the apparatus comprises an ambient IoT device.

25. The apparatus according to any one of claims 1 to 24, wherein an ambient IoT device comprises the apparatus.

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