Device-to-device message forwarding mechanism using positioning protocol

Abstract

Under the condition that all related user equipment cannot directly communicate with a server, a mechanism is necessary to be implemented through an intermediate node to forward information contained in a side chain positioning protocol (SLPP) message. Development of an efficient, reliable and safe side chain positioning information forwarding mechanism is a major challenge in the field. Solving this challenge is crucial for realizing accurate positioning in various scenarios, especially under the condition that all parties cannot communicate directly due to distance limitation, network coverage problems or other limitations.

Description

[0001] Cross-referencing

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 584,915, filed September 25, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to wireless communication, and more specifically, to communication between multiple devices participating in positioning operations on a side link port. Background Technology

[0004] In modern wireless systems, such as 3GPP 5G cellular networks, device-to-device (D2D) communication capabilities are increasingly supported. These capabilities allow user devices (UEs) to communicate directly without intervention from network infrastructure nodes. This direct communication interface has various names, including sidechain, PC5, short-range communication (SRC), or point-to-point interface. A significant advantage of this direct communication capability is its ability to determine UE location and distances between UEs through a process called sidechain localization.

[0005] Sidechain positioning is based on transmitting and measuring specific signals on the sidechain interface, which are called sidechain positioning reference signals (SL-PRS). While this technique can be used in conjunction with device-to-network measurements, such as those performed via the 3GPP Uu interface in so-called joint PC5 / Uu positioning operations, the main focus of this discussion is the sidechain positioning aspect of these operations.

[0006] Current sidechain localization implementations face several key challenges that hinder their optimal performance in modern wireless communication systems. These challenges include restricted node-to-node communication, inflexible message structures, data synchronization issues from disparate sources, difficulties in scaling in large-scale networks, poor adaptability to changing network environments, and barriers to deployment across different network types. Most critically, message routing and network management can become extremely complex in topologies where direct connections between all nodes are not always possible. These challenges collectively impede the protocol's efficiency, scalability, and reliability, particularly in scenarios involving multiple devices. Addressing these issues is crucial for improving the protocol's effectiveness and ensuring its suitability for next-generation wireless communication systems where accurate and secure sidechain localization is increasingly important. Summary of the Invention

[0007] One embodiment discloses a method of message forwarding in a wireless system. The method includes receiving, by a first node, a first message from a second node. The first message includes a message body and an identifier of a third node. The method further includes identifying, by the first node, the third node as a destination based on the identifier of the third node, and sending, by the first node, a second message to the third node. The second message includes information related to the first message and an identifier of the second node as a source. The first message and the second message are constructed using a Sidelink Positioning Protocol (SLPP) or a Ranging and Sidelink Positioning Protocol (RSPP).

[0008] Another embodiment discloses a method of message forwarding in a wireless system. The method includes receiving, by a first node, a first message from a second node. The first message includes a message body and an identifier of a third node. The method further includes starting a countdown upon receiving the first message at the first node, identifying, by the first node, the third node as a destination based on the identifier of the third node, and sending, by the first node, a second message to the third node when the countdown is completed. The second message includes information related to the first message and an identifier of the second node as a source. The first message and the second message are constructed using a Sidelink Positioning Protocol (SLPP) or a Ranging and Sidelink Positioning Protocol (RSPP).

[0009] One embodiment discloses a user equipment (UE) comprising a memory and a processor coupled to the memory. The processor is configured to receive a first message from a second node, identify a third node as a destination, and send a second message to the third node. The first message and the second message are constructed using a Sidelink Positioning Protocol (SLPP) or a Ranging and Sidelink Positioning Protocol (RSPP). The first message includes a message body and an identifier of the third node as a destination. The second message includes information related to the first message and an identifier of the second node as a source.

[0010] Another embodiment discloses a user equipment (UE) comprising a memory and a processor coupled to the memory. The processor is configured to receive a first message from a second node, start a countdown upon receiving the first message, identify a third node as a destination, and send a second message to the third node when the countdown is completed. The first message and the second message are constructed using a Sidelink Positioning Protocol (SLPP) or a Ranging and Sidelink Positioning Protocol (RSPP). The first message includes a message body and an identifier of the third node. The second message includes information related to the first message and an identifier of the second node as a source.

[0011] These and other objects of the present application will not be evident from the following detailed description of the preferred embodiments, which, taken in conjunction with the various drawings, illustrate various embodiments of the application. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 An embodiment of a wireless system is shown.

[0013] Figure 2 Another embodiment of a wireless system is shown.

[0014] Figure 3 Another embodiment of a wireless system based on Figure 1 is shown.

[0015] Figure 4 Another embodiment of a wireless system based on Figure 2 is shown.

[0016] Figure 5 An embodiment of a SLPP forwarding mechanism is shown.

[0017] Figure 6 An alternative embodiment of a SLPP forwarding mechanism is shown.

[0018] Figure 7 An alternative embodiment of a SLPP forwarding mechanism is shown.

[0019] Figure 8 An alternative embodiment of a SLPP forwarding mechanism is shown.

[0020] Figure 9 A timer-based approach for optimizing the SLPP forwarding mechanism is shown.

[0021] Figure 10 A simplified block diagram of a wireless device according to these embodiments is shown. DETAILED DESCRIPTION

[0022] The present disclosure relates to wireless communication systems and methods, with primary focus on 3GPP-based systems, but whose applicability extends beyond these particular implementations. Those skilled in the art will recognize immediately that the technology, devices and systems described herein can be practiced without certain specific details, which have been omitted in the interest of clarity. Well-known methods, procedures, components and circuits have not been described in detail to avoid obscuring the core concepts presented.

[0023] The present disclosure is particularly applicable to various wireless multiple access systems. These include, but are not limited to, Code Division Multiple Access (CDMA), Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single-Carrier Frequency Division Multiple Access (SC-FDMA), and Multi-Carrier Frequency Division Multiple Access (MC-FDMA) systems. Each of these multiple access systems can be implemented with certain radio technologies.

[0024] For example, CDMA can be implemented by a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA can be implemented by a radio technology such as Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), or Enhanced Data Rates for GSM Evolution (EDGE). OFDMA can be implemented by a radio technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, or Evolved UTRA (E-UTRA).

[0025] It is noted that UTRA is part of Universal Mobile Telecommunication System (UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) is a part of Evolved UMTS (E-UMTS) using E-UTRA. In 3GPP LTE context, OFDMA is utilized for the downlink (DL) transmission and SC-FDMA is utilized for the uplink (UL) transmission. The evolution of 3GPP LTE includes a number of iterations including LTE-Advanced (LTE-A), LTE-A Pro, and 5G New Radio (NR).

[0026] While the embodiments described in this specification concern primarily 3GPP-based wireless communication systems, the features presented are not limited to such systems. The principles and methods discussed can be adapted and applied to other wireless communication systems that can not strictly follow 3GPP standards.

[0027] In 3GPP and other wireless communication standards, various Radio Access Networks (RANs) are used to facilitate communication between base stations (which can be referred to as RAN nodes, network nodes, or simply nodes) and wireless communication devices known as User Equipment (UEs). These RANs can include, but are not limited to, Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution RAN (GERAN), Universal Terrestrial Radio Access Network (UTRAN), Evolved Universal Terrestrial Radio Access Network (E-UTRAN), and Next Generation RAN (NG-RAN).

[0028] In 3GPP standards, the Side-Link Positioning Protocol (SLPP), which can also be referred to as the Ranging and Side-Link Positioning Protocol (RSPP), is a communication protocol specifically designed to facilitate positioning operations in cellular networks, particularly in scenarios involving Device-to-Device (D2D) or side-link communication. SLPP plays a key role in enabling and coordinating various side-link positioning-related functions between UEs and network entities such as the Location Management Function (LMF).

[0029] A side-link positioning procedure typically involves UEs operating in two roles: a target UE, whose position is sought by the system, and one or more anchor UEs, which serve as reference points for determining the target's position. In the case of a ranging operation, where the goal is to determine the distance between two UEs, the system can model the scenario in different ways. For example, it can consider both UEs as targets, or it can consider one as a target and the other as an anchor. In addition to the target UE and the anchor UEs, a side-link positioning operation can involve a third "server" role of a UE, which will be described below.

[0030] To meet different scenarios and requirements, multiple side-link positioning methods have been developed. These methods include Side-Link Time Difference of Arrival (SL-TDOA), Side-Link Relative Time of Arrival (SL-RTOA), Side-Link Angle of Arrival (SL-AoA), and Side-Link Round-Trip Time (SL-RTT). While these methods differ in their specifics, they all share a common foundation: the position of the target is computed using measurements of SL-PRSs.

[0031] The exact nature of SL-PRS transmission and measurement depends on the positioning method used. In some cases, the target UE can transmit SL-PRSs, which are then received and measured by the anchor UEs. In other cases, the opposite can occur, with the anchor UEs transmitting and the target UE measuring. Some methods can involve bidirectional transmission and measurement. Regardless of the specific method, the resulting SL-PRS measurements typically contain information about various signal characteristics. This information can include data about the time, angle, phase, and / or signal strength of the received SL-PRSs.

[0032] Once these measurements are collected, they are communicated to a server for processing and interpretation. Depending on the implementation, the server can take different forms. In some cases, it can be a special UE known as a server UE, for example, with the capability to interpret SL-PRS measurements and form a position estimate for the target UE and / or a range estimate between the two participating UEs. The server UE can be the same as the target UE or one of the anchor UEs, or it can be a separate UE that communicates with a certain subset of the target and anchor UEs.

[0033] In other scenarios, particularly when one or more UEs are within cellular network coverage, the computation of the position estimate can be performed by a network entity called a Location Management Function (LMF). The LMF is a server in the network with the capability to coordinate assistance data and measurements and can compute the position estimate based at least in part on SL-PRS measurements. For the purposes of this discussion, the term "server" is used generically to refer to either a server UE or an LMF.

[0034] Communications between the participating UEs and the server are conducted through a specialized protocol, called the Sidelink Positioning Protocol (SLPP), which can also be referred to as the Ranging and Sidelink Positioning Protocol (RSPP). The SLPP contains a variety of messages that can be sent from a UE in one functional role (target / anchor / server) to a UE in another functional role (typically in a different functional role). The SLPP can also be used for communications between a UE participating in sidelink positioning and an LMF. The protocol is designed to be flexible, and can be transported over a variety of lower protocol layers between the endpoints.

[0035] However, in certain embodiments, a significant challenge arises: the server can not be able to communicate directly with all of the participating UEs. The meaning of "direct communication" depends on the type of server. In the case of an LMF, direct communication refers to communication over the air interface of the cellular system, typically involving wireless communication between a UE and a base station, which is then coupled to the LMF through one or more network interfaces. For a server UE, direct communication refers to communication over the sidelink interface itself.

[0036] It is noted that anchor user equipment (UE) and target user equipment (UE) are expected to communicate directly, as they need to receive and measure each other's sidelink positioning reference signal (SL-PRS) transmissions. Thus, the communication challenge primarily applies to interactions involving a server. However, in certain cases, these methods can also need to be applied to communications between a target user equipment and an anchor user equipment, or between two anchor user equipment.

[0037] In cases where all relevant user equipment cannot directly communicate with the server, it is necessary to implement a mechanism to forward information contained in a sidelink positioning protocol (SLPP) message through an intermediate node. Developing an efficient, reliable, and secure sidelink positioning information forwarding mechanism is a significant challenge in this field. Solving this challenge is crucial for enabling accurate positioning in various scenarios, especially in cases where direct communication between all parties is not possible due to distance limitations, network coverage issues, or other restrictions. SLPP is structured to support a range of positioning-related transactions and message types. These can include, but are not limited to, capability exchange, assistance data transfer, position information transfer, and error indication. Each transaction type has a specific use in the positioning process. For example, capability exchange allows devices to inform each other or the network of their positioning-related capabilities, while assistance data transfer enables the sharing of information to aid more accurate positioning calculations. The protocol is designed to be flexible and extensible, allowing various information elements and / or metadata to be incorporated within its messages. These elements can be structured using a standardized format, such as Abstract Syntax Notation One (ASN.1), which provides a method for consistently encoding and decoding message content across different implementations and devices.

[0038] SLPP messages typically contain key components such as transaction type identifiers, source and destination information, and a message body carrying the actual payload data. One key feature of SLPP is its ability to handle complex communication patterns, including one-to-many and many-to-one scenarios, which are particularly useful in sidelink positioning operations, as multiple devices can need to coordinate their activities or share information simultaneously.

[0039] For terms and technologies not explicitly defined or described in this specification, the reader is referred to wireless communication standard documents published prior to this disclosure (e.g., 3GPP specifications). These documents provide comprehensive definitions and explanations of relevant terms and technologies.

[0040] It is important to note that while this discussion frequently uses 5G terminology, this usage is not limiting. Alternative nomenclature can be used in various implementations to refer to nodes and / or interfaces serving similar purposes as described herein. The principles and methods discussed can be adapted to future wireless communication technologies beyond 5G.

[0041] Figure 1An embodiment of a wireless system 100 is shown having multiple user equipment (UEs) capable of sidelink positioning. The wireless system 100 includes two anchor UEs 101 and 102, a target UE 103, and a server UE 104, which is distinct from the other UEs. The target UE 103 can communicate directly with the anchor UEs 101 and 102 and the server UE 104. The server UE 104 has a direct communication link with the target UE 103 and the anchor UE 101, but not with the anchor UE 102. The two anchor UEs 101, 102 can communicate directly with each other and the target UE 103, while the anchor UE 101 also maintains a direct link with the server UE 104. Sidelink positioning reference signals (SL-PRSs) can be transmitted by the anchor UEs 101 and 102 and / or the target UE 103 over a sidelink interface. While Figure 1 Bidirectional transmission of SL-PRSs is shown, but it is noted that this can only occur from anchor to target or vice versa.

[0042] It is noted that a UE transmitting SL-PRSs is referred to as a SL-PRS Tx UE, while a UE receiving and measuring SL-PRSs is referred to as a SL-PRS Rx UE. In some cases, a single UE can act as both a SL-PRS Tx and Rx UE.

[0043] Figure 2 An embodiment of a wireless system 200 is shown. The wireless system 200 includes two anchor UEs 201 and 202, a target UE 203, a base station (BS) 204, and a core network (CN) 205, as shown. The CN 205 includes a Location Management Function (LMF) 206. It is understood that other nodes of the CN 205, although not explicitly shown, can exist. The BS 204 is communicatively connected to the LMF 206, which connection can traverse other CN nodes, such as an Access and Mobility Management Function (AMF), which are omitted from the figure to maintain clarity. The nodes of the CN 205 can communicate through a service bus.

[0044] In the illustrated configuration, two anchor UEs 201 and 202 are capable of direct communication through the PC5 interface. Target UE 203 can communicate directly with anchor UEs 201, 202 through the PC5 interface and with BS 203 through the Uu interface. In addition, anchor UE 201 can communicate directly with BS 203 through the Uu interface. Notably, BS 204 lacks direct communication capabilities with anchor UE 202, which can be due to anchor UE 202 being located outside the coverage area of BS 204. It is assumed that any UE capable of direct communication with BS 204 can also communicate with LMF 206, e.g., for the purpose of exchanging SLPP signaling.

[0045] In Figure 1 and Figure 2 a common challenge observed is that the server (whether a UE or LMF) cannot communicate directly with anchor UE 202. This limitation poses a potential obstacle to effective sidelink positioning, which can require the server to determine the capabilities of anchor UE 202, exchange assistance data, retrieve SL-PRS measurement results, and perform other necessary operations.

[0046] To address this challenge, Figure 3 a high-level solution based on Figure 1 the illustrated wireless system 100 is presented. In this solution, target UE 303 assumes the role of forwarding information between server UE 304 and anchor UE 302. This forwarding process is executed through a series of steps: In the first step, server UE 304 sends a first SLPP message to target UE 303. This message contains first information explicitly directed to anchor UE 302. Subsequently, target UE 303 sends a second SLPP message to anchor UE 302, conveying the aforementioned first information. The next step involves anchor UE 302 sending a third SLPP message to target UE 303. This message contains second information intended for server UE 304. In the final step, target UE 303 sends a fourth SLPP message to server UE 304, containing the second information received from anchor UE 302.

[0047] This series of message exchanges enables server UE 304 to effectively communicate with anchor UE 302, overcoming the limitation of direct communication. This mechanism enhances the flexibility and robustness of the sidelink positioning system, enabling more comprehensive and efficient positioning operations even in scenarios where direct communication between all nodes is not feasible.

[0048] The present disclosure relates to methods and systems for forwarding SLPP messages in a cellular network where direct communication between all nodes is not feasible. Various embodiments are described to facilitate efficient information exchange between network entities, particularly in scenarios involving a server (possibly a Location Management Function or a Server User Equipment), an anchor UE, and a target UE. These methods address the common challenge of enabling communication between network elements that lack direct connectivity, thereby enhancing the overall functionality and efficiency of the Sidelink Positioning System.

[0049] Figure 4 One high-level solution is illustrated in FIG. 2, which demonstrates a scenario where a target UE 202 forwards information between a LMF 206 and an anchor UE 204. This process involves a series of SLPP message transmissions, enabling indirect communication between the LMF 206 and the anchor UE 204. The method includes four distinct steps, each involving the transmission of a SLPP message. Figure 2 Another high-level solution for the wireless system 200 is illustrated in FIG. 4. In the wireless system 400, the target UE 403 is involved in forwarding information between the LMF 406 and the anchor UE 402. This process involves a series of SLPP message transmissions, enabling indirect communication between the LMF 406 and the anchor UE 402. The method includes four different steps, each involving the transmission of a SLPP message.

[0050] The process begins with the Location Management Function (LMF) 406 sending a first Sidelink Positioning Protocol (SLPP) message to the target User Equipment (UE) 403. This message includes information explicitly indicating the destination as the anchor UE 402. Including this destination information is crucial as it enables the target UE to recognize its role in the forwarding process.

[0051] Next, the target UE 403, upon receiving and processing the first SLPP message, sends a second SLPP message to the anchor UE 402. This second message includes the first information originally sent by the LMF 406. Essentially, the target UE 403 acts as an intermediary, relaying information from the LMF 406 to the anchor UE 402. Note that the LMF 406 can be located in the Core Network (CN) 405.

[0052] The next step involves the anchor UE 402 sending a third SLPP message to the target UE. This message includes second information indicating the destination as the LMF 406. This step illustrates the bidirectionality of the communication, allowing the anchor UE 402 to respond or feedback information to the LMF 406.

[0053] In the final step, the target UE 403 completes the exchange by sending a fourth SLPP message to the LMF 406. This message includes the second information received from the anchor UE 402. Through this series of messages, the LMF 406 is able to exchange information with the anchor UE 402, despite the lack of direct communication between them.

[0054] This approach provides a robust solution for scenarios where network topology or other limitations prevent direct communication between certain nodes. By utilizing the target UE as an intermediary, the system can maintain effective information exchange and coordination between all relevant parties during a sidelink positioning procedure.

[0055] Figure 5 An embodiment of the SLPP forwarding mechanism is presented. This embodiment is presented in a simplified wireless system 500, comprising two UEs 501, 502 and a server 503. The approach involves forwarding the entire SLPP message as a Protocol Data Unit (PDU) within another SLPP message. This approach provides a simple forwarding solution, albeit with certain trade-offs.

[0056] The procedure begins with the server 503 (which can be an LMF or a server UE) sending a first SLPP message to UE 501. This first SLPP message includes destination information indicating that it is intended for UE 502. Including this destination information is crucial, as it enables UE 501 to understand its role in the forwarding process without needing to interpret the full contents of the message.

[0057] Upon receiving the first SLPP message, UE 501 processes the message to determine the intended recipient. Recognizing that the target of the message is UE 502, UE 501 prepares to forward the message. Rather than extracting and repackaging the contents, UE 501 encapsulates the entire first SLPP message as a PDU within a second SLPP message.

[0058] Next, UE 501 sends this second SLPP message to UE 502. The second message contains the complete first SLPP message as its payload, preserving all of the original information, including the destination details. When UE 502 receives this message, it can extract and process the original message from the server as if it was received directly.

[0059] This approach offers several advantages. Primarily, it simplifies the processing required of the intermediary UE (e.g., UE 501 in this example). UE 501 does not need to interpret or modify any part of the first message, only recognizing the destination information. This is particularly beneficial in scenarios where the intermediary UE may not have the capability or authorization to handle the contents of the forwarded message.

[0060] However, this approach has certain limitations. Since the entire original message is forwarded, including elements such as the original destination information, there can be unnecessary data transmitted over the air. This can impact network efficiency, especially in scenarios where bandwidth is limited or a large number of messages are being processed.

[0061] Furthermore, this approach does not allow different parts of a single SLPP message to be sent to different UEs. Each forwarded message must be targeted to a single recipient, which can not be ideal in all network configurations or use cases.

[0062] It is important to note that while Figure 5 While the description focuses on the forward path (from server 503 to UE 502 through UE 501), a similar mechanism can be employed in the reverse direction. In this case, UE 502 can send a message directed to server 503, which UE 501 will forward to server 503 using the same PDU encapsulation method.

[0063] Figure 6 Another embodiment of a SLPP forwarding mechanism is presented. This approach aims to address some of the limitations of the previous method by allowing more selective forwarding of message content. In this mechanism, the intermediary UE extracts specific parts of the SLPP message and repackages them as part of a new SLPP message for transmission to the final recipient.

[0064] The process begins with server 603 (which can be an LMF or a server UE) sending a first SLPP message to UE 601. This message includes two key components: destination information indicating that the content target is UE 602 and a message body. The message body can take a standardized format, such as an SLPP-MessageBody information element (IE) encoded using Abstract Syntax Notation One (ASN.1).

[0065] Upon receiving this message, UE 601 processes the message to identify the intended recipient and extract the relevant content. Instead of forwarding the entire original message, UE 601 prepares a new SLPP message for transmission to UE 602.

[0066] Next, UE 601 sends a second SLPP message to UE 602. This new message includes a copy of the message body in the original SLPP message. The message body in the second message can maintain the same structure and format as the original message (e.g., SLPP-MessageBody IE in ASN.1 format). The second SLPP message can also include additional source information indicating that the content originated from a server. This source information enables the final recipient (i.e., UE 602) to understand the origin of the message, which can be crucial for proper handling and response.

[0067] This approach offers several advantages over the previous one. By extracting and forwarding only the necessary content, it eliminates the transmission of unnecessary information over the air, such as the original destination information, which is no longer needed once the message reaches UE 601. This can result in more efficient use of network resources, especially in scenarios where bandwidth is limited or the volume of messages is large.

[0068] Like the previous approach, this approach can also be applied in the reverse direction, although not explicitly shown in the figure. In this case, UE 602 can send a third SLPP message containing a message body pointing to the server, and UE 601 will extract the relevant content and forward it to server 603 in a fourth SLPP message.

[0069] While this approach addresses the issue of forwarding unnecessary information, it still has a limitation. Since SLPP messages typically contain only one message body, this approach does not allow a single message to contain information targeting multiple target UEs. This limitation can be significant in more complex network scenarios that require efficient multi-point communication, as well as in scenarios where multiple UEs (e.g., multiple anchor UEs) have limited direct communication with the server.

[0070] To address the limitations of the previous approaches, Figure 7 A more flexible sidelink positioning protocol (SLPP) forwarding mechanism is demonstrated in the following. This approach allows multiple entries in a single SLPP message, each with its own destination information. The approach is demonstrated in a simplified wireless system 700, which includes three user equipment (UE) 701, 702, 703 and a server 704 (which can be a location management function (LMF) or a server UE), demonstrating its ability to handle more complex communication scenarios.

[0071] In this mechanism, SLPP messages are associated with a specific transaction type. The figure uses capability exchange as an example, but it should be noted that this approach can be applied to various SLPP transaction types, such as assistance data transmission, location information transmission, error indication, etc.

[0072] The process begins with the server sending a first SLPP message to UE 701. In the example shown, this is an SLPP Request Capabilities message, but the principle applies equally to other message types. The key feature of this message is its structure: it contains a message body, which in turn contains multiple entries, each with its own destination information and content.

[0073] In particular, in this example, the message body of the first SLPP message contains two entries. The first entry, labeled "ReqCap entry 1", includes destination information indicating that it is intended for UE 702, as well as a first set of message content (labeled "Contents 1") for UE 2 to receive and interpret. The second entry, labeled "ReqCap entry 2", contains destination information specifying UE 703 as the intended recipient, along with a second set of message content (labeled "Contents 2") for UE 703 to use.

[0074] When UE 701 receives this first SLPP message, it processes the message to identify the multiple entries and their respective destinations. Recognizing that the two entries need to be delivered to their intended recipients separately, UE 701 prepares to forward the information accordingly.

[0075] In the next step, UE 701 sends a second SLPP message to UE 702. This message is of the same type as the first SLPP message (e.g., in this case, an SLPP Request Capabilities message). The second message contains a message body, which includes two key elements. First, it contains source information indicating that the content comes from the server, ensuring that UE 702 understands the origin of the information. Second, it includes a copy of the first set of message content ("Contents 1") extracted from the first entry of the original message.

[0076] Similarly, UE 701 then sends a third SLPP message to UE 703. This message is also of the same type as the original message. The message body contains source information identifying the server as the origin of the content, along with a copy of the second set of message content ("Contents 2") extracted from the second entry of the original message.

[0077] This approach offers significant advantages in terms of flexibility and efficiency. It allows a single SLPP message to carry information for multiple recipients, which is particularly useful in complex network scenarios or when coordinating activities of multiple UEs. The intermediary UE (e.g., UE 701 in this case) can efficiently process and forward the relevant parts of the message to each intended recipient, reducing the number of transmissions required compared to sending separate messages for each recipient.

[0078] In addition, the method preserves the context and transaction type of the original message, ensuring that each recipient UE can handle the information within the appropriate framework. The source information included in the forwarded message also ensures that the recipient is aware of the origin of the information, which is crucial for proper interpretation and response.

[0079] While Figure 7 the example in illustrates forwarding information from a single source (server 704) to multiple destinations (UE 702 and UE 703), the same principles can be applied in the reverse direction. Figure 8 This reverse scenario is illustrated, where UE 801 is responsible for forwarding information from multiple sources to a single destination.

[0080] Figure 8 The scenario depicted in can be considered a response to the process shown in Figure 7 In Figure 8 , UE 801 acts as an intermediary, responsible for forwarding information from multiple sources (in this case, UE 802 and UE 803) to a single destination, server 804 (which could be an LMF or a UE). The process involves multiple steps, demonstrating the flexibility of the SLPP forwarding mechanism in handling various communication patterns.

[0081] The process begins with UE 802 sending a first SLPP message to UE 801. In this example, the message is a SLPP Provide Capabilities message, but the same principle applies to other message types. This first message contains a message body, which includes two key elements: the first destination information, indicating that the content is intended for server 804, and a first set of message content (labeled "Contents 1").

[0082] In the next step, UE 803 sends a second SLPP message to UE 801. In this example, the message is also a SLPP Provide Capabilities message. Similar to the first message, it contains a message body, which includes destination information specifying the server as the intended recipient, and a second set of message content (labeled "Contents 2").

[0083] Upon receiving these messages, UE 801 processes them and recognizes that both contain information intended for the same destination (the server). Instead of forwarding each message separately, UE 801 prepares to combine the information into a single message for efficient transmission.

[0084] In the final step of this process, UE 801 sends a third SLPP message to the server. In this example, the message, like the previous ones, is a SLPP Provide Capabilities message. The key feature of this message is its structure: its message body contains two list entries, effectively combining the information from both received messages.

[0085] The first entry in the merged message is labeled "ProvCap entry 1" and contains two elements: a first source information indicating that its content comes from UE 802, and a copy of the first set of message content ("Contents 1") received in the message from UE 2. Similarly, the second entry is labeled "ProvCap entry 2" and includes source information identifying UE 803 as the source of its content, and a copy of the second set of message content ("Contents 2") received in the message from UE 803.

[0086] This approach offers several advantages. It allows for efficient merging of information from multiple sources into a single message, reducing the number of transmissions required and potentially saving network resources. The inclusion of source information in each entry ensures that the server can distinguish between information provided by different UEs, maintaining the context and origin of each piece of information.

[0087] However, it should be noted that in practical implementations, the first and second SLPP messages can not be delivered to UE 801 simultaneously. This introduces a challenge: UE 801 needs to implement some form of processing to identify when the contents should be bulk-merged into a single outgoing message, rather than forwarding each received message individually.

[0088] To address this challenge, Figure 9 A timer-based approach is demonstrated for optimizing the forwarding process when messages are not received simultaneously. This approach allows the UE to bulk-process multiple received messages before forwarding them to the server, improving efficiency while ensuring timely delivery of information.

[0089] In step 1, the process begins with UE 902 sending a first SideLink Positioning Protocol (SLPP) message (in this example, an SLPP Provide Capabilities message) to UE 901. In step 2, UE 901 starts a timer upon receiving this message. This timer serves as a mechanism to allow a time window for receiving additional messages before initiating the forwarding process.

[0090] During the running of the timer, in step 3, UE 903 sends a second SLPP message (also an SLPP Provide Capabilities message in this example) to UE 901. UE 901 receives and stores this SLPP message along with the first SLPP message.

[0091] In step 4, after a predetermined time has elapsed, the timer started by UE 901 expires. This expiration serves as a trigger for UE 901 to construct an outgoing message using the information received from UE 902 and UE 903 during the timer period.

[0092] After the expiry of the timer, in step 5, the UE 901 composes a third SLPP message. This message is structured according to the principles described earlier: its message body contains multiple list entries, each containing information from one of the received messages and an indication of its origin. In this case, the message will include a first entry for the information from the SLPP message of UE 902 and a second entry for the information from the SLPP message of UE 903.

[0093] Finally, in step 6, the UE 901 sends this third SLPP message to the server 904, effectively delivering the information from UE 902 and UE 903 in a single transmission.

[0094] This timer-based approach offers flexibility and efficiency in handling message forwarding. It allows the integration of multiple messages received in a short period of time, potentially reducing the number of transmissions and optimizing network resource usage. At the same time, the use of a timer ensures that information is not indefinitely delayed if no additional messages are received.

[0095] It is important to note that additional criteria can be incorporated into this process to further optimize its operation. For example, if the UE 901 is triggered to send its own information to the server 904, it can immediately compose and send a message that includes its own information and any stored information from received SLPP messages, without waiting for the timer to expire.

[0096] Another potential optimization involves the delivery deadline. One or both of the received SLPP messages can contain information indicating a delivery deadline. In this case, the UE 901 can be programmed to compose and send the integrated message at any time before the earliest deadline, ensuring timely delivery of time-sensitive information.

[0097] Figure 10 A simplified block diagram of a wireless device according to an embodiment is shown, in particular a user equipment (UE) 1001 and a network entity 1011. The network entity 1011 can be implemented as a location management function (LMF), comprising several key components. These components include a memory 1012, a processor 1013, a protocol stack 1080, and a measurement processor 1090. The memory 1012 can be used to store program instructions and data 1020 that control the operation of the network entity 1011. The processor 1013 can execute these program instructions to analyze and interpret positioning-related data transmitted through SLPP messages. It is responsible for extracting relevant information to determine or refine a position estimate, processing various types of measurements that are crucial for accurate positioning in sidelink scenarios, such as time of arrival, angle of arrival, and signal strength indicators. It focuses on efficient analysis of raw measurement data, transforming it into meaningful positioning information.

[0098] Working in conjunction with the processor 1013, the measurement processor 1090 is dedicated to processing measurements received through the SLPP. The protocol stack 1080 facilitates standardized communication and data exchange between network entities and other devices in the network, ensuring proper encapsulation, addressing, and routing of SLPP messages.

[0099] These components collectively form a comprehensive system for processing and analyzing positioning data in sidelink communications. The synergy between the processor 1013, the memory 1012, and the measurement processor 1090 is crucial for enabling the system to perform accurate position determinations in device-to-device (D2D) and sidelink communication environments. By effectively processing measurements transmitted via SLPP, this integrated system significantly enhances the overall accuracy and reliability of sidelink positioning systems, providing a solid foundation for advanced location-based services and applications.

[0100] According to embodiments, the UE 1001 includes a memory 1002, a processor 1003, and a radio frequency transceiver 1004 coupled with an antenna 1005. The processor 1003 can be implemented using various technologies, such as a digital signal processor (DSP) or an application-specific integrated circuit (ASIC), to process received baseband signals and invoke different functional modules and circuits to perform functions in the UE 1001. The memory 1002 stores data and program instructions 1010 executed by the processor 1003 to control UE operations.

[0101] The UE 1001 further includes a set of functional modules and control circuits 1070 and a protocol stack 1060. The protocol stack 1060 includes layers and / or sub-layers, such as the non-access stratum (NAS), radio resource control (RRC), packet data convergence protocol / radio link control (PDCP / RLC), medium access control (MAC), and physical layer (PHY). The system modules and circuits 1070 include PDU session and PDN connection processing circuitry 1021, QoS flow and EPS bearer processing circuitry 1022, and configuration and control circuitry 1023.

[0102] Regarding the protocol stacks 1080 and 1060, located in the network entity 1011 and the UE 1001, respectively, these protocol stacks implement a layered communication protocol framework, with each layer performing specific functions to enable efficient and reliable data exchange. These protocol stacks ensure interoperability between different devices and systems by adhering to standardized protocols, thereby abstracting the complexity of network communication from higher-level applications.

[0103] In particular, the protocol stacks 1080 and 1060 integrate SLPP (also referred to as RSPP) and LTE Positioning Protocol (LPP). As such, these protocol stacks also serve as fundamental components that manage a wide range of tasks required for efficient positioning operations, especially in D2D or sidelink communication scenarios. Their responsibilities include comprehensive message handling, implementation of various forwarding mechanisms, timer management, transaction handling, SL-PRS coordination, multi-UE communication facilitation, interface management, security implementation, interoperability assurance, and error handling. By performing these diverse functions, they enable efficient coordination of positioning operations, optimize communication processes, and ensure robust and accurate positioning capabilities in various network scenarios.

[0104] Various embodiments and optimizations provide a range of flexible and efficient solutions for SLPP message forwarding in different network configurations. By addressing the challenges of indirect communication in sidelink positioning systems, these approaches enhance the overall functionality and efficiency of cellular networks, especially in cases where direct communication between all nodes is not possible.

[0105] Furthermore, various embodiments provide significant advancements in wireless communication systems, particularly in sidelink positioning. The main advantage lies in the enhanced flexibility that allows communication between various network entities even without direct links, enabling positioning operations in a wider range of network topologies. The protocol's ability to facilitate indirect communication through intermediary UEs ensures effective information exchange in cases where direct communication is not possible. This flexibility is combined with efficient resource utilization, as various forwarding mechanisms, especially those that integrate multiple messages, reduce unnecessary data transmission, optimizing network resource usage in bandwidth-constrained environments.

[0106] The protocol's support for complex communication patterns, including one-to-many and many-to-one scenarios, makes it particularly suitable for coordinating positioning activities among multiple devices simultaneously. Its adaptability to various network conditions, including scenarios where messages are not received simultaneously, is enhanced through timer-based forwarding functions. The protocol's comprehensive functionality, which integrates various transaction types within a single framework, simplifies the overall positioning process in cellular networks.

[0107] Furthermore, the invention improves scalability by allowing easy integration of additional user equipment (UEs) or network entities without significant reconfiguration. It improves positioning accuracy by facilitating the exchange of detailed positioning information and capabilities between devices. The use of a structured format like ASN.1 ensures standardization, providing consistent and interoperable exchange of positioning-related information between different devices and implementations. Finally, the protocol's scalability allows future adaptability, enabling integration as new positioning methods or technologies evolve. These collective advantages contribute to establishing a more robust, efficient, and versatile positioning system in cellular networks, addressing current implementation challenges and paving the way for advanced location-based services and applications.

[0108] Furthermore, various embodiments have broad applications in the field of wireless communication, with a particular focus on sidelink positioning in cellular networks. The main use is to enhance device-to-device (D2D) positioning, making positioning determination between devices more accurate and efficient without constant reliance on network infrastructure. This capability is particularly valuable in scenarios where traditional positioning methods like GPS may be limited, such as indoor environments or urban areas with poor satellite visibility. The technology also significantly improves network coverage by allowing devices to relay positioning information, effectively extending the range of positioning services beyond direct base station coverage. This functionality is particularly beneficial in rural or remote areas where network infrastructure is sparse.

[0109] Applications extend to various industries, including automotive, emergency services, Internet of Things (IoT), and smart city infrastructure. In vehicle-to-everything (V2X) communication, it improves the accuracy and reliability of vehicle positioning, which is crucial for advanced driver assistance systems and autonomous driving technologies. For emergency services, improved positioning capabilities help locate callers more accurately, especially in challenging environments. In IoT deployments, the protocol's efficient resource usage and ability to handle multiple devices simultaneously make it well-suited for tracking numerous low-power devices. The technology also has significant potential in urban planning and management, providing precise location data for public services, traffic management, and infrastructure monitoring. Additionally, its applicability in indoor navigation in large buildings, asset tracking in logistics, augmented reality applications, and network optimization for operators demonstrates its versatility and potential to significantly impact various industries by improving the accuracy, efficiency, and reliability of positioning services in different scenarios and environments.

[0110] In the context of the foregoing embodiments and their various implementations, it is important to note that the sidelink positioning protocol (SLPP) can also be referred to as the ranging and sidelink positioning protocol (RSPP). This alternative terminology reflects a comprehensive description of the protocol capabilities (see 3GPP TS 23.586). In the preceding discussion, wherever SLPP is mentioned, it is understood that RSPP can be used interchangeably. This equivalence applies to all aspects of the protocol as previously described, including its structure, message types, transaction categories, and forwarding mechanisms.

[0111] It is important to note that this terminology flexibility does not change the core functionality or characteristics of the protocol, as detailed in the foregoing description. Whether referred to as SLPP or RSPP, the protocol maintains its capabilities in the areas of capability exchange, assistance data transfer, position information transfer, and error indication. Likewise, the protocol's adaptability to various network topologies and its support for complex communication patterns remain unchanged. In the practical application and future development of this technical standard (i.e., 3GPP standards), both terms (SLPP and RSPP) can be encountered. Implementers, researchers, and users of the protocol should be aware of this dual nomenclature to avoid confusion and ensure clear communication when discussing or using the positioning protocol.

[0112] For clarity in the present specification, certain terminology conventions are followed. The singular forms "a," "an," and "the" are intended to cover the plural forms as well, unless the context clearly indicates otherwise. The term "and / or" refers to and encompasses any and all possible combinations of one or more of the associated listed items. The terms "includes," "containing," "comprises," and "comprising" specify the presence of stated features, integers, steps, operations, elements, and / or components but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0113] The term "exemplary" is used herein to mean "serving as an example, instance, or illustration," and should not necessarily be construed as preferred or advantageous over other aspects or designs.

[0114] In the specification and claims, ordinal designators, such as "first," "second," and so on, are used to distinguish between instances of like elements. These designators do not necessarily imply a chronological or sequential order, priority, or a spatial arrangement, or a functional relationship between the elements, unless specifically stated. Rather, they are used to uniquely identify and distinguish between individual instances of elements that share common names or descriptions.

[0115] Unless specifically stated, the term "some" refers to one or more. Various combinations of the terms "at least one" or "one or more" followed by a list of items (for example, A, B, or C) are to be construed to include any combination of the listed items, including individual items and multiples of items.

[0116] The terms "coupled," "connected," "connecting," and "electrically connected" are used synonymously to describe the state of being electrically or electronically linked. When an entity is described as being "in communication" with another entity or entities, it means that the sending and / or receiving of electrical signals, which can include voice or non-voice data / control information, is possible whether such signals are analog or digital in nature.

[0117] In the context of this patent specification, the term "user equipment" (UE) encompasses a broad range of devices with radio communication capabilities. This definition includes, but is not limited to, smartphones, particularly handheld touchscreen mobile computing devices capable of connecting to one or more cellular networks, personal data assistants (PDAs), pagers, laptop computers, desktop computers, wireless handsets, and any computing device equipped with a wireless communication interface. User equipment can also be referred to by a variety of alternative terms, including but not limited to: client, mobile, mobile terminal, user terminal, mobile unit, mobile station, mobile user, subscriber, user, remote station, access agent, user agent, receiver, radio, reconfigurable radio, or reconfigurable mobile. These terms should be considered as used interchangeably in the context of this document.

[0118] The scope of UEs also extends to Internet of Things (IoT) devices. IoT UEs are characterized by a network access layer designed for low-power IoT applications, which typically involve short-lived UE connections. These IoT UEs can employ various technologies for data exchange, including machine-to-machine (M2M), machine-type communications (MTC), or massive MTC (mMTC). This data exchange can occur through a public land mobile network (PLMN) with an MTC server or device, using proximity services (ProSe) or device-to-device (D2D) communications with other UEs, or through a sensor network or Internet of Things network. Notably, M2M or MTC data exchange is typically initiated by the machine itself, rather than by human intervention.

[0119] Internet of Things networks, as described in this specification, describe a system of Internet of Things user equipment (UE) interconnection. These UEs can include embedded computing devices with unique identification integrated into a broader Internet infrastructure. IoT UEs can execute background applications, such as keep-alive messages or status updates, to maintain and facilitate connectivity within the IoT network.

[0120] The UE is configured to establish a communicative coupling with a radio access network (RAN) over a radio interface. The radio interface is a physical communication interface or layer designed to operate with various cellular communication protocols. These protocols can include, but are not limited to, global system for mobile communications (GSM) protocols, code division multiple access (CDMA) network protocols, push-to-talk (PTT) protocols, PTT over cellular (POC) protocols, universal mobile telecommunications system (UMTS) protocols, third generation partnership project long-term evolution (3GPP LTE) protocols, 5G protocols, and new radio (NR) protocols.

[0121] As one specific example, the UE and RAN can utilize a Uu interface (e.g., an LTE-Uu interface) to exchange control plane data. This exchange occurs over a protocol stack that includes multiple layers: a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a radio resource control (RRC) layer. In this context, downlink (DL) transmissions refer to data transmitted from the RAN to the UE, while uplink (UL) transmissions refer to data transmitted from the UE to the RAN.

[0122] Further, the UE can use a sidelink to communicate directly with other UEs, facilitating device-to-device (D2D), peer-to-peer (P2P), and / or ProSe communications. For example, a ProSe interface can contain one or more logical channels. These channels include, but are not limited to, a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), a physical sidelink discovery channel (PSDCH), and a physical sidelink broadcast channel (PSBCH).

[0123] The various aspects described herein can be implemented using a variety of hardware and software components. These components can include processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gates or transistor logic, or discrete hardware components. In this context, a processor can be a microprocessor, but can also be any conventional processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0124] The aspects described in this specification can be implemented in hardware and software instructions. The instructions can be stored on various types of computer-readable media, including, but not limited to, random access memory (RAM), flash memory, read-only memory (ROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), registers, a hard disk, a removable disk, a CD-ROM, or any other storage medium known in the art. In a typical configuration, the storage medium is connected to the processor so that the processor can read information from, and write information to, the medium. In some configurations, the storage medium can be part of the processor.

[0125] In some embodiments, the computing instructions can be executed by an operating system, which can include, but is not limited to, Microsoft Windows, Apple Mac OS X, macOS or iOS, various distributions of the Linux operating system, or the Google Android operating system.

[0126] Some embodiments can involve a computer from a distributed system, e.g., a networked environment in which the various clients and / or servers have different, but potentially overlapping, capabilities. In such embodiments, a client can run software implementing the client portion of the system and method, while a server handles requests from these clients. Communications between the clients and the server can be carried out over one or more electronic networks, which can include the Internet, a wide area network, a mobile phone network, a wireless network (e.g., Wi-Fi, 5G), or a local area network, using any known network protocol.

[0127] In embodiments in which the systems described in this specification collect user information, measures can be taken to protect user privacy and data. In particular, users can be given the opportunity to opt in or opt out of programs or features that collect personal information, e.g., data related to user preferences or smart device usage patterns. Additionally, in some embodiments, data protection measures can be implemented to anonymize collected information before storage or use. For example, users’ identities can be anonymized to prevent the association of personally identifiable information with a particular user. Additionally, user preference and interaction data can be generalized, possibly based on broader demographic categories, rather than being associated with individual users.

[0128] It is noted that the operational steps described in any exemplary aspect of the specification are provided as examples and discussion only. The steps can be performed in various different sequences than shown, and some steps can be omitted, combined, or further partitioned into additional steps. The steps of the steps in the figures can be modified in light of the teachings of the specification.

[0129] Certain embodiments can include all of the features described herein, and other embodiments can include only those features necessary to practice the core teachings of the application. Conversely, other embodiments can omit certain features described herein without departing from the scope of the invention. Such flexibility in the choice of elements and features of the invention is considered to be within the scope of the invention, and is contemplated by at least one embodiment. This flexibility in the choice of elements and features of the invention is not considered to be a disclaimer of scope of the application, or a means-plus-function clause, with respect to a set of elements in the abstract.

[0130] The logical stages shown in the figures can be reordered, combined, or divided, if they are not sequentially dependent. The ordering and grouping of the stages described herein are not exhaustive, and the skilled person will find other arrangements. The stages can be implemented by hardware, firmware, software, or any combination thereof.

[0131] The drawings and description provided in this specification provide detailed illustrations of various embodiments of the invention. However, the skilled person will understand that these embodiments can be implemented without necessarily adhering to every specific detail provided herein. In certain instances, well-known methods, procedures, components and circuits have been referred to without detailed explanation in order not to obscure the key aspects of the embodiments. It is noted that the drawings provided in this specification, including any component diagrams, are for illustration purposes only and can not be drawn to scale. This allows for variations and adjustments within the scope of the invention while clearly demonstrating the inventive concept.

[0132] The skilled person will readily observe that many modifications and alterations can be made to the devices and methods while retaining the teachings of the invention. Accordingly, the above disclosure should only be interpreted according to the limits of the appended claims.

Claims

1. A method for message forwarding in a wireless system, comprising: A first node receives a first message from a second node, the first message including a message body and an identifier of a third node; The first node identifies the third node as the destination based on the identifier of the third node; as well as The first node sends a second message to the third node, the second message including information related to the first message and an identifier of the second node as the source; The first message and the second message are constructed using the Sidechain Positioning Protocol (SLPP) or the Ranging and Sidechain Positioning Protocol (RSPP).

2. The method of claim 1, wherein: The first node is a first user equipment (UE); The second node is a Management Function (LMF) or a second UE; and The third node is either the LMF or a third UE.

3. The method of claim 1, wherein the information associated with the first message includes a protocol data unit (PDU), and the PDU includes the first message.

4. The method of claim 1, wherein the information associated with the first message includes a message body.

5. The method of claim 1, wherein the information associated with the first message includes one or more information elements (IEs) associated with the first message.

6. The method of claim 1, further comprising: The first node receives a third message from a fourth node, the third message including a message body and an identifier of the third node as the destination; Package the information related to the third message and the identifier of the fourth node as the source into a fourth message; and The first node sends the fourth message to the second node.

7. A method for message forwarding in a wireless system, comprising: A first node receives a first message from a second node, the first message including a message body and an identifier of a third node; A countdown begins when the first node receives the first message. The first node identifies the third node as the destination based on the identifier of the third node; as well as When the countdown is complete, the first node sends a second message to the third node. The second message includes information related to the first message and an identifier of the second node as the source. The first message and the second message are constructed using the Sidechain Positioning Protocol (SLPP) or the Ranging and Sidechain Positioning Protocol (RSPP).

8. The method of claim 7, further comprising: After the countdown is started, the first node receives a fourth message from a fourth node; as well as The information related to the fourth message is packaged into the second message.

9. The method of claim 8, wherein: The first node is a first user equipment (UE); The second node is a Management Function (LMF) or a second UE; The third node is either the LMF or a third UE; and The fourth node is either the LMF or a fourth UE.

10. The method of claim 7, wherein the information associated with the first message includes a protocol data unit (PDU), and the PDU includes the first message.

11. The method of claim 7, wherein the information associated with the first message includes a message body.

12. The method of claim 7, wherein the information associated with the first message includes one or more information elements (IEs) associated with the first message.

13. A user equipment (UE), comprising: A memory; as well as A processor coupled to the memory is configured as follows: Receive a first message from a second node; Identify a third node as the destination; and Send a second message to the third node; in: The first message and the second message are constructed using the Sidechain Positioning Protocol (SLPP) or the Ranging and Sidechain Positioning Protocol (RSPP); The first message includes a message body and an identifier for the third node as the destination; and The second message includes information related to the first message and the identifier of the second node as the source.

14. The UE as claimed in claim 13, wherein: The second node is a Management Function (LMF) or a second UE; and The third node is either the LMF or a third UE.

15. The UE of claim 13, wherein the information is associated with the first message including a protocol data unit (PDU), and the PDU includes the first message.

16. The UE of claim 13, wherein the information is associated with the first message including the message body.

17. The UE of claim 13, wherein the information is associated with the first message which includes one or more information elements (IEs) associated with the first message.

18. A user equipment (UE), comprising: A memory; as well as A processor coupled to the memory is configured as follows: Receive a first message from a second node; Upon receiving the first message, a countdown begins; Determine a third node as the destination; and When the countdown is complete, send a second message to the third node; Wherein: The first message and the second message are constructed using the Sidechain Positioning Protocol (SLPP) or the Ranging and Sidechain Positioning Protocol (RSPP); The first message includes a message body and an identifier for a third node; and The second message includes information associated with the first message and the identifier of the second node as the source.

19. The UE of claim 18, wherein the processor is further configured to: After starting the countdown, receive a fourth message from a fourth node; and The information associated with the fourth message is packaged into the second message.

20. The UE of claim 19, wherein: The second node is either a Management Function (LMF) or a second UE; The third node is either the LMF or a third UE; and The fourth node is either the LMF or a fourth UE.

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