Network time monitoring and adjustment

Abstract

Apparatus and methods for monitoring network timing are disclosed. One method includes: storing (300) information about a reference propagation delay between the apparatus and one or more radio access nodes; controlling (302) receiving a reference signal from the one or more radio access nodes, the reference signal including information about the transmission time of the signal; determining (304) the reception time of the reference signal; determining (306) the propagation delay of the reference signal based on the time difference between the reception time and the transmission time; and determining (308) the correctness of the time reference of the apparatus and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay.

Description

Technical Field

[0001] Exemplary and non-limiting embodiments of the present invention generally relate to wireless communication systems. Exemplary and non-limiting embodiments of the present invention particularly relate to apparatus and methods in wireless communication networks. Background Technology

[0002] In wireless telecommunications synchronization systems such as GSM, LTE-A (Advanced Long Term Evolution), or NR (5G), information about network time, such as Coordinated Universal Time (UTC), can be provided to user terminals via a radio interface. Network time can be used, for example, for synchronizing the user terminal's internal clock. Generally, the time reference in a user terminal is poorly stable, and the internal clock needs to be periodically synchronized with the network time. This also applies to the radio access nodes serving the user terminals. The internal clock of the radio access node needs to be synchronized with the network's precise reference clock, PRC. The PRC can be obtained, for example, from GNSS time or from atomic clocks.

[0003] If PRC synchronization is lost, the mobile network can continue operating for a given period of time based on the network unit's internal clock. For example, if the network time is based on GNSS time, a failure or outage of the satellite-based system may occur. Examples of this could be solar flares or interference attacks. Furthermore, in the case of atomic clocks, system failures may occur. If the accumulated time or frequency error due to some failure becomes too large, further operation of the network may be at risk. This also applies to operation on the radio interface, where user terminals can continue operating for a relatively short period of time without synchronization. Summary of the Invention

[0004] To provide a basic understanding of some aspects of the invention, a brief overview of the invention is presented below. This overview is not a comprehensive summary of the invention. It is not intended to identify key elements of the invention or to define its scope. Its sole purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that follows.

[0005] According to one aspect of the present invention, an apparatus in a communication network is provided, comprising: components for storing information about a reference propagation delay between the apparatus and one or more radio access nodes; components for controlling the reception of a reference signal from the one or more radio access nodes, wherein the reference signal includes information about a transmission time of the signal; components for determining the reception time of the reference signal; components for determining the propagation delay of the reference signal based on a time difference between the reception time and the transmission time; and components for determining the correctness of a time reference of the apparatus and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay.

[0006] According to one aspect of the present invention, an apparatus in a communication network is provided, comprising: components for controlling the transmission of a reference signal to a user terminal, wherein the reference signal includes information about the transmission time of the signal; components for controlling the reception of an instruction from the user terminal, wherein the instruction includes information about the correction of a time reference for the apparatus; and components for correcting the time reference of the apparatus based on the instruction.

[0007] According to one aspect of the present invention, a method is provided, comprising: storing information about a reference propagation delay between a device and one or more radio access nodes; controlling the reception of a reference signal from the one or more radio access nodes, the reference signal including information about the transmission time of the signal; determining the reception time of the reference signal; determining the propagation delay of the reference signal based on a time difference between the reception time and the transmission time; and determining the correctness of a time reference of the device and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay.

[0008] According to one aspect of the present invention, a method in a communication network is provided, comprising: controlling the transmission of a reference signal to a user terminal, the reference signal including information about the transmission time of the signal; controlling the reception of an instruction from the user equipment, the instruction including information about correction of a time reference for the device; and correcting the time reference of the device based on the instruction.

[0009] According to one aspect of the invention, a computer program is provided, comprising instructions for causing a device to perform at least the following operations: storing information about a reference propagation delay between the device and one or more radio access nodes; controlling the reception of a reference signal from the one or more radio access nodes, the reference signal including information about the transmission time of the signal; determining the reception time of the reference signal; determining the propagation delay of the reference signal based on the time difference between the reception time and the transmission time; and determining the correctness of the time reference of the device and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay.

[0010] According to one aspect of the invention, a computer program is provided, comprising instructions for causing a device to perform at least the following operations: controlling the transmission of a reference signal to a user terminal, the reference signal including information about the transmission time of the signal; controlling the reception of an instruction from the user terminal, the instruction including information about the correction of a time reference for the device; and correcting the time reference of the device based on the instruction.

[0011] One or more examples of the implementation are illustrated in more detail in the following figures and description. Other features will be apparent from the description and figures and from the claims. Embodiments and / or examples and features (if any) described in this specification that are not within the scope of the independent claims are to be construed as examples useful for understanding various embodiments of the invention. Attached Figure Description

[0012] In the following, the invention will be described in more detail with reference to the accompanying drawings, in which:

[0013] Figure 1 and Figure 2 This diagram illustrates a simplified system architecture example of a communication system.

[0014] Figure 3 and Figure 4 These are flowcharts illustrating some embodiments;

[0015] Figure 5A , Figure 5B , Figure 6A , Figure 6B , Figure 7A and Figure 7B Examples of some embodiments are illustrated;

[0016] Figure 8 This is a flowchart illustrating an example of user equipment calibration;

[0017] Figure 9 Example of numerical values ​​shown in the diagram;

[0018] Figure 10 This is a flowchart illustrating an example of operation of a calibrated user equipment;

[0019] Figure 11 , Figure 12 , Figure 13 and Figure 14 This is a flowchart illustrating some examples of some embodiments;

[0020] Figure 15 and Figure 16 Examples of apparatuses for some embodiments are illustrated. Detailed Implementation

[0021] The following embodiments are merely examples. Although the specification may refer to "a," "an," or "some" embodiments in several places, this does not mean that every such reference refers to the same embodiment or that a feature applies only to a single embodiment. Individual features of different embodiments may also be combined to provide other embodiments. Furthermore, the words "comprising" and "including" should be understood not to limit the described embodiments to consisting only of those features mentioned, and such embodiments may also include features, structures, units, modules, etc., not specifically mentioned.

[0022] Some embodiments of the present invention are applicable to user equipment, user terminals, base stations, eNodeBs, gNodeBs, distributed implementations of base stations, network units of communication systems, corresponding components, and / or any combination of different communication systems that support the required functions.

[0023] The protocols and specifications used in communication systems, servers, and user equipment (especially in wireless communications) are evolving rapidly. This evolution may necessitate additional modifications to embodiments. Therefore, all words and expressions should be interpreted broadly, and they are intended to illustrate rather than limit the embodiments.

[0024] In the following description, different exemplary embodiments will be used with radio access architectures based on Advanced Long Term Evolution (LTE-A, LTE-A) or New Radio (NR, 5G) (as examples of access architectures to which the embodiments can be applied), but the embodiments are not limited to such architectures. These embodiments can also be applied to other types of communication networks with suitable components by appropriately adapting parameters and processes. Some examples of other options for suitable systems are Universal Mobile Telecommunications System (UMTS) Radio Access Network (UTRAN or E-UTRAN), Long Term Evolution (LTE, the same as E-UTRA), Wireless Local Area Network (WLAN or WiFi), and Global Microwave Access Interoperability (WiMAX). Personal Communication Services (PCS) Wideband Code Division Multiple Access (WCDMA), systems using Ultra Wideband (UWB) technology, sensor networks, Mobile Ad Hoc Networks (MANET), and Internet Protocol Multimedia Subsystem (IMS), or any combination thereof.

[0025] Figure 1 An example of a simplified system architecture is depicted, showing some units and functional entities (all or some of which are logical units), the implementation of which may differ from that shown. Figure 1 The connections shown are logical connections; the actual physical connections may differ. This will be apparent to those skilled in the art, except... Figure 1 In addition to those shown, the system typically includes other functions and structures.

[0026] However, the embodiments are not limited to the system given as an example, but those skilled in the art can apply the solution to other communication systems equipped with the necessary features.

[0027] Figure 1 The example illustrates a portion of an exemplary radio access network.

[0028] Figure 1 Devices 100 and 102 are shown. Devices 100 and 102 may be, for example, user equipment or user terminals. Devices 100 and 102 are configured to wirelessly connect with node 104 on one or more communication channels. Node 104 is further connected to core network 106. In one example, node 104 may be an access node, such as an (e / g)NodeB that provides services to devices in a cell or serves devices. In one example, node 104 may be a non-3GPP access node. The physical link from the device to the (e / g)Node B is referred to as an uplink or reverse link, and the physical link from the (e / g)Node B to the device is referred to as a downlink or forward link. It should be understood that the (e / g)Node B or its functionality can be implemented using any entity suitable for this purpose, such as a node, host, server, or access point.

[0029] A communication system typically includes more than one (e / g)Node B, which may also be configured to communicate with each other over wired or wireless links designed for this purpose. These links may be used for signaling purposes. An (e / g)Node B is a computing device configured to control the radio resources of the communication system to which it is coupled. A Node B may also be referred to as a base station, access point, or any other type of interface device, including relay stations capable of operating in a wireless environment. An (e / g)Node B includes or is coupled to a transceiver. A connection provided from the transceiver of the (e / g)Node B to an antenna element establishes a bidirectional radio link with the device. The antenna element may include multiple antennas or antenna elements. The (e / g)Node B is further connected to the core network 106 (CN or Next Generation Core NGC). Depending on the system, the corresponding part on the CN side may be a Serving Gateway (S-GW, which routes and forwards user data packets), a Packet Data Network Gateway (P-GW) for providing connectivity from the device (UE) to an external packet data network, or a Mobility Management Entity (MME), etc.

[0030] This device (also referred to as user equipment, subscriber unit, user equipment (UE), user terminal, terminal equipment, etc.) illustrates a type of apparatus to which resources on the air interface are allocated and assigned; therefore, any feature described herein as a device can be implemented using a corresponding apparatus (such as a relay node). An example of such a relay node is a Layer 3 relay (self-backhaul relay) directed toward a base station.

[0031] This device typically refers to a wireless mobile communication device (e.g., portable or non-portable computing device) that operates with or without a Universal Subscriber Identity Module (USIM), including but not limited to the following types of devices: mobile stations (mobile phones), smartphones, personal digital assistants (PDAs), cell phones, devices using wireless modems (alarm or measuring devices, etc.), laptops and / or touchscreen computers, tablets, game consoles, laptops, and multimedia devices. It should be understood that the device can also be a nearly exclusive uplink device, an example of which is a camera or camcorder that uploads images or video clips to the network. The device can also be a device capable of operating in an Internet of Things (IoT) network, in which objects are provided with the ability to transmit data over the network without human-to-human or human-to-computer interaction, for example, for smart grids and connected vehicles. The device can also utilize the cloud. In some applications, the device may include a user portable device (such as a watch, headset, or glasses) with a radio component, and computation is performed in the cloud. The device (or, in some embodiments, a Layer 3 relay node) is configured to perform one or more user equipment functions.

[0032] The various techniques described in this paper can also be applied to cyber-physical systems (CPS) (systems where collaborative computing elements control physical entities). CPS enables the realization and utilization of a large number of interconnected information and communication technology (ICT) devices (sensors, actuators, processors, microcontrollers, etc.) embedded in physical objects at different locations. Mobile cyber-physical systems (where the physical systems under discussion have inherent mobility) are a subcategory of cyber-physical systems. Examples of mobile physical systems include mobile robots and electronic devices transported by humans or animals.

[0033] Furthermore, although the device is described as a single entity, different units, processors, and / or memory units can be implemented. Figure 1 (Not all of them are shown in the image).

[0034] 5G enables the use of multiple-input multiple-output (MIMO) antennas, far more base stations or nodes than LTE (the so-called small cell concept), including macro sites that cooperate with small base stations and utilize various radio technologies depending on service requirements, use cases, and / or available spectrum. 5G mobile communications support a wide range of use cases and related applications, including video streaming, augmented reality, different data sharing methods, and various forms of machine-type applications (such as (massive) machine-type communications (mMTC)), including vehicle safety, various sensors, and real-time control. 5G is expected to have multiple radio interfaces, namely sub-6 GHz, cmWave, and mmWave, and can also integrate with existing legacy radio access technologies (such as LTE). Integration with LTE can be implemented, at least in the early stages, where macro coverage is provided by LTE and 5G radio interface access comes from systems via small cells aggregated to LTE. In other words, 5G is planned to support inter-RAT operability (such as LTE-5G) and inter-RI operability (inter-radio interface operability, such as sub-6 GHz). – cmWave, below 6GHz – cmWave – Both mmWave and network slicing are considered to be used in 5G networks. One such concept is network slicing, where multiple independent and dedicated virtual sub-networks (network instances) can be created within the same infrastructure to run services with different requirements for latency, reliability, throughput, and mobility.

[0035] The current architecture in LTE networks is entirely distributed across the radio and entirely centralized in the core network. Low-latency applications and services in 5G require bringing content closer to the radio, leading to local bursts and multi-access edge computing (MEC). 5G enables analytics and knowledge generation to occur at the source of the data. This approach requires leveraging resources that may not be continuously connected to the network, such as laptops, smartphones, tablets, and sensors. MEC provides a distributed computing environment for hosting applications and services. It also enables the storage and processing of content closer to cellular subscribers to accelerate response times. Edge computing encompasses a wide range of technologies, such as wireless sensor networks, mobile data acquisition, mobile signature analytics, collaborative distributed peer-to-peer self-organizing networking and processing, and can also be categorized as local cloud / fog computing and grid / grid computing, exposed computing, mobile edge computing, micro-cloud, distributed data storage and retrieval, autonomous and self-healing networks, remote cloud services, augmented and virtual reality, data caching, the Internet of Things (massive connectivity and / or latency critical), and critical communications (autonomous vehicles, traffic safety, real-time analytics, time-critical control, healthcare applications).

[0036] The communication system can also communicate with or use other networks such as the public switched telephone network or the Internet. The communication network can also support the use of cloud services; for example, at least a portion of the core network operations can be performed as a cloud service (this is in...). Figure 1 (Described by “Cloud” 114). The communication system may also include a central control entity, thereby providing facilities for different operators’ networks to collaborate, for example, in spectrum sharing.

[0037] Edge cloud technology can be introduced into the radio access network (RAN) by using Network Functions Virtualization (NVF) and Software-Defined Networking (SDN). Using edge cloud technology means that access node operations will be performed, at least partially, in servers, hosts, or nodes operatively coupled to remote radio heads or base stations including radio sections. Node operations can also be distributed across multiple servers, nodes, or hosts. Applying a cloud RAN architecture enables real-time RAN functions to be performed on the RAN side (in distributed unit DU 104), while non-real-time functions are performed centrally (in centralized unit CU 108).

[0038] It should also be understood that the division of labor between core network operations and base station operations may differ from, or even not exist, in LTE. Some other technological advancements available are big data and all-IP, which could potentially transform how networks are built and managed. 5G (or New Radio) networks are designed to support multiple hierarchical structures where MEC servers can be placed between the core and base stations or NodeBs (gNBs). It should be understood that MEC can also be applied to 4G networks.

[0039] 5G can also utilize satellite communications to enhance or supplement the coverage of 5G services, for example, by providing backhaul. Possible use cases include providing service continuity for machine-to-machine (M2M) or Internet of Things (IoT) devices or passengers in vehicles, or ensuring the availability of critical communications and future rail / maritime / aviation communications. Satellite communications can utilize geostationary orbit (GEO) satellite systems or low Earth orbit (LEO) satellite systems, particularly mega-constellations (systems deploying hundreds of (nano) satellites). At least one satellite 110 in a mega-constellation can cover several network entities supporting satellites that create terrestrial cells. Terrestrial cells can be created via ground relay nodes 104 or via gNBs located on the ground or in satellites.

[0040] It will be apparent to those skilled in the art that the depicted system is merely an example of a portion of a radio access system, and in practice the system may include multiple (e / g)Node Bs that can access multiple radio cells, and the system may also include other devices such as physical layer relay nodes or other network units. At least one of the (e / g)Node Bs may be a home (e / g)Node B. Furthermore, multiple different types of radio cells and multiple radio cells may be provided within the geographical area of ​​the radio communication system. Radio cells may be macrocells (or umbrella cells, which are typically large areas with diameters of up to tens of kilometers) or smaller cells, such as microcells, femtocells, or picocells. Figure 1 The (e / g) Node B can provide any type of these cells. Cellular radio systems can be implemented as multi-layer networks comprising several types of cells. Typically, in a multi-layer network, one access node provides one or more cells of one type, and therefore multiple (e / g) Node Bs may be required to provide this network structure.

[0041] To meet the needs of improved communication system deployment and performance, the concept of "plug and play" (e / g) Node B has been introduced. Typically, in addition to the Home (e / g) Node B (H(e / g) Node B), networks capable of using "plug and play" (e / g) Node B also include Home Node B gateways or HNB-GWs. Figure 1 (Not shown in the image). HNB gateways (HNB-GWs), typically installed in carrier networks, can aggregate traffic from a large number of HNBs back to the core network.

[0042] Figure 2 An example of a communication system based on 5G network components is illustrated. A user terminal or user equipment 200 communicates with a data network 204 via a 5G network 202. The user equipment 200 is connected to a base station or gNB 206, which provides connectivity to the data network 204 to the user equipment via one or more user plane functions 208. The user equipment 200 is further connected to a core access and mobility management function (AMF) 210, which is the control plane core connector for the (radio) access network and can be viewed from this perspective as a 5G version of the mobility management entity (MME) in LTE. The 5G network further includes a session management function (SMF) 212 and a policy control function 214. The SMF 212 is responsible for subscriber sessions, such as session establishment, modification, and release, while the policy control function 214 is configured to control network behavior by providing policy rules to the control plane functions. The network further includes an operator's operations and maintenance (O&M) unit 220.

[0043] For wireless communication synchronization systems to operate, a common time reference is required. Otherwise, communication over the radio interface may fail because network units send / receive at incorrect times. This requirement for a stable and accurate time source necessitates the provision of a precise reference clock (PRC), such as GNSS time or an atomic clock. This can be costly for network operators and also introduces the risk of single points of failure, potentially related to the availability of PRC services. Therefore, even in stand-alone operation of radio access nodes such as eNBs, monitoring the accuracy of the provided network time via the radio interface is necessary when the PRC is lost. The possibility of correcting timing errors would be valuable.

[0044] Figure 3 This is a flowchart illustrating an embodiment. The flowchart illustrates an example of the operation of a device or network unit that acts as a user equipment or part of a user equipment.

[0045] In step 300, the device is configured to store information about the reference propagation delay between the device and one or more radio access nodes.

[0046] In step 302, the device is configured to control the reception of a reference signal from one or more radio access nodes, the reference signal including information about the transmission time of the signal.

[0047] In step 304, the device is configured to determine the reception time of the reference signal.

[0048] In step 306, the device is configured to determine the propagation delay of the reference signal based on the time difference between the receiving time and the transmitting time.

[0049] In step 308, the device is configured to determine the correctness of the time reference of the device and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay.

[0050] In an embodiment, the device may be configured to determine that the device’s time base is incorrect if the determined propagation delay associated with more than one radio access node is not equal to the stored propagation delay.

[0051] In an embodiment, the device may be configured to determine that the time base of the first radio access node is incorrect if the determined propagation delay and the stored propagation delay associated with the first radio access node are not equal and the determined propagation delay and the stored propagation delay associated with the second radio access node are equal with a given margin.

[0052] In the embodiment, a correction is determined for an incorrect time base.

[0053] In one embodiment, the device can be configured to control the transmission of an instruction to a first radio access node, the instruction including information about corrections for an incorrect time reference.

[0054] In an embodiment, the device can be configured to correct the device’s time reference based on a determined correction.

[0055] Figure 4 This is a flowchart illustrating an embodiment. The flowchart illustrates an example of the operation of a device or network unit that acts as a radio access node or part of a radio access node.

[0056] In step 400, the device is configured to control the transmission of a reference signal to the user equipment, the reference signal including information about the transmission time of the signal.

[0057] In step 402, the device is configured to control receiving an instruction from the user equipment, the instruction including information about the correction of the device's time reference.

[0058] In step 404, the device is configured to correct its time reference based on the instruction.

[0059] In this embodiment, a user equipment (UE) can be used to monitor both the timing of the radio access node and the UE's own timing. Therefore, the method described above ensures that time alignment within the network monitored by the UE remains stable even when the radio access node operates in standalone mode without an infinite PRC.

[0060] Figure 5A and Figure 5B An example is illustrated. The attached figure shows User Equipment 500. User Equipment 500 (which may be designated as Reference User Terminal Ref UT or Reference User Equipment Ref UE) can be an Internet of Things (IoT) device or a broadband UE. It can be located in the coverage area of ​​multiple cells from different radio access nodes (e.g., eNBs). Figure 5A In the example, for simplicity, Ref UE 500 is shown in the coverage area of ​​the two access nodes 502, 504. In embodiments, Ref UE may be fixed, for example, mounted on a mast or any other suitable facility. In embodiments, the location of Ref UE may enable line-of-sight visibility of the radio access nodes within the coverage area of ​​Ref UE.

[0061] The line-of-sight distance between the Ref UE and eNB within the coverage area can be measured, and then that distance can be converted into a time equivalent, since microwaves travel at the speed of light using a radio interface.

[0062] In this embodiment, the radio access node can be configured to transmit or broadcast a reference signal that includes information about the physical signal transmission time T0. Time T0 uses the access node's internal clock as a time reference. Let us assume in this document that eNB1 502 transmits the reference signal. The transmission time can be denoted as T0(e1). The reference signal can be any selected frame, subframe, or symbol.

[0063] The reference signal transmitted by the radio access node can be received by the Ref UE at time T1. Time T1 uses the Ref UE's internal clock as a reference / base. The reception time can be denoted as T1(ue).

[0064] Therefore, the arrival time TOA (time difference T1–T0) corresponds to the signal propagation delay, but uses two different reference time sources—the access node and the Ref UE. Because synchronous transmission is used, the time relationships between many measurements can be compared. Using the above notation, the time difference of the reference signal transmitted by eNB1 502 can be denoted as T. prop (eNB1,T e1 ,T ue ).

[0065] As mentioned above, the Ref UE can be configured to store information about the reference propagation delay between the device and one or more radio access nodes. The reference propagation delay 506 between the user equipment 500 and the access node eNB1502 can be denoted as T. ref (eNB1), and the reference propagation delay 510 between user equipment 500 and access node eNB2 504 can be denoted as T. ref (eNB2).

[0066] The determined TOA propagation delay between the Ref UE and the access node can be compared with the reference propagation delay used for the same access node. Any deviation in the TOA measurement can indicate a time drift of the time reference source on either the access node or the Ref UE side. By analyzing TOA measurements for other access nodes, the Ref UE can determine whether the reference clock drift exists on the access node side or the Ref UE side.

[0067] In this embodiment, the Ref UE can propose time compensation for the access node or the Ref UE accordingly. The Ref UE can identify the source of the time drift and can provide time correction for the internal reference clock of the eNB or the Ref UE. This approach provides bottom-up time synchronization, unlike the traditional top-down methods used for time synchronization.

[0068] exist Figure 5A and Figure 5B In the example, the reference propagation delay between user equipment 500 and access node eNB1 502 is 506T. ref The reference propagation delay between eNB1 and user equipment 500 and access node eNB2 504 is 510T. ref (eNB2) was determined at an earlier point in time.

[0069] For example, the distance between User Equipment (Ref UE) and Access Nodes eNB1 502 and eNB2 504 can be measured, for example, using a laser rangefinder with millimeter accuracy. The propagation time is proportional to this distance. For example, for Access Node eNB1, the following applies:

[0070]

[0071] Among them, T ref (eNB1) is the propagation delay of the reference signal to eNB1 based on distance measurement, where c is the speed of light, and D is the distance to eNB1. ref (eNB1) is the measured reference distance between Ref UE and eNB1.

[0072] Access node eNB1 502 sends reference signal 508 to user equipment 500 at time T0, and user equipment receives the signal at time T1. Similarly, access node eNB2 504 sends reference signal 512 to user equipment 500 at time T3, and user equipment receives the signal at time T4.

[0073] Using the above method, the corresponding TOA ring can be determined, with radii of 514 and 516, which are proportional to the TOA propagation delay. Taking eNB1 as an example, the equation used to determine the reference signal propagation delay is as follows:

[0074] T prop (eNB1,T e1 ,T ue )=T1(T ue )–T0(T e1 (Equation 2)

[0075] Among them, T prop (eNB1,T e1 ,T ue ) is the reference signal propagation delay, which is a function of the distance between Ref UE and eNB1, and the reference clocks of eNB1 and Ref UE are: T1(T ue ) is the time received by the physical reference signal of the Ref UE, which depends on the Ref UE clock, T0(T e1 The time is the time when the physical reference signal of eNB1 is sent, which depends on the eNB1 clock.

[0076] exist Figure 5A In the example, the reference clocks of Ref UE, eNB1, and eNB2 are at the correct time. Therefore, the following conditions, Equations 3 and 4, are satisfied (again, using eNB1 as an example):

[0077] T prop (eNB1,T e1 ,T ue ) = T ref (eNB1)(Equation 3)

[0078]

[0079] If the above equations match, there are no errors in the reference clock. Both the access point eNB and the Ref UE are synchronized with the precise reference clock PRC, which can be defined as a function T. ue (T e1 (T) This is a typical scenario for mobile network operation. Typically, the access point provides synchronization for the user equipment. Therefore, under normal circumstances, the reference time in the user equipment is a function of the user equipment's own reference time, which in turn is a function of the access point's reference time.

[0080] Based on equations 3 and 4, the reference time T can be determined. ue or T e1 This is because the relative TOA propagation delay needs to be substantially equal to the reference delay determined by the precise distance measurement device. If equations 3 and 4 are satisfied, the time base of the access point and the Ref UE is ordered. If these equations do not match, the reference time of the access point or the Ref UE is incorrect.

[0081] Furthermore, if one of these equations does not match (by analyzing equations 3 and 4 for multiple access points), it can be determined whether the instability of the reference time source is related to the access points, i.e., whether there is a common point of failure—RefUE. If an error exists for one access point but the equations for other access points match, the corresponding access point may have incorrect timing in its reference clock. If the equations for more than one access point indicate an error, the incorrect timing is in the RefUE.

[0082] In an embodiment, a given error tolerance may be applied when determining the correctness of equations 3 and 4.

[0083] Figure 5A and Figure 5B The diagram illustrates a situation where the propagation delay of the reference signals transmitted by both eNB1 and eNB2 is essentially equal to the propagation delay of the corresponding reference signals. Figure 6A and Figure 6BThe diagram then illustrates an example where access point eNB1 502 loses synchronization with the PRC for a period of time. This means that eNB1 needs to rely on its own internal clock to maintain clock synchronization. In this case, the time relationship can be represented as T. ue (T e1 (T e1 )).exist Figure 6A and Figure 6B In the example, the lack of PRC has caused instability in the clock of eNB1.

[0084] Figure 6A and Figure 6B The illustration shows an example where the TOA propagation delay distance between Ref UE and eNB1 is not substantially equal to the reference delay to eNB1, and the conditions defined by Equations 3 and 4 are not satisfied. Propagation delay T1(T ue )–T0(T e1 (Greater than the reference delay T) ref (eNB1):

[0085] T1(T ue )–T0(T e1 )>T ref (eNB1)

[0086] Since the positions of eNB1 and Ref UE have not changed, the cause of the TOA error is likely a drift in the reference time source at either eNB1 or Ref UE. This is an option because the microwave velocity is constant. At this point, based on a single TOA measurement of one eNB, it may not be possible to determine if the problem lies with the reference time source T at the Ref UE. ue Or the eNB1 reference time source T e1 .

[0087] The source of time drift can be clearly indicated by analyzing other eNB pairs—the Ref UE and the associated TOA measurements. Figure 6A and Figure 6B In the example, the TOA measurement for eNB2 satisfies the conditions in equations 3 and 4:

[0088] T4(T ue )–T3(T e2 ) = T ref (eNB2)

[0089] This indicates that the Ref UE reference time source T ue and eNB2 reference time source T e2 It has a common reference clock (within a given tolerance). For the TOA measurement of eNB1, the same Ref UE clock T is used. ueIt can be determined that the problem is related to the eNB1 internal clock T. e1 It is related because it affects T0(T) e1 The time determined by ).

[0090] exist Figure 6A and Figure 6B In the example, the error caused an excessively long propagation delay. A similar situation could occur where the propagation delay of a specific TOA is shorter than the corresponding reference delay, i.e., the propagation delay T1(T ue )–T0(T e1 Delay T compared to reference ref (eNB1) is shorter.

[0091] Figure 7A and Figure 7B Another example is illustrated. In this example, neither the reference signal transmitted by eNB1 nor the reference signal transmitted by eNB2 satisfies Equation 3:

[0092] T1(T ue )–T0(T e1 )>T ref (eNB1)

[0093] T4(T ue )–T3(T e2 )>T ref (eNB2)

[0094] This can happen, for example, when Ref UE 500 has lost synchronization for any reason. An incorrect reference time at Ref UE can lead to incorrect TOA measurements because T... ue It will affect T1(T) ue ) and T4(T ue The time determined by T. ue TOA measurements are public, therefore any TOA propagation measurement may be incorrect.

[0095] It can be noted that current user equipment needs to periodically synchronize with the radio access node, a process that requires random access and consumes radio resources.

[0096] like Figure 7A and Figure 7B A similar scenario could be that the propagation delay of any TOA is shorter than the delay of any relevant reference.

[0097] It can be noted that typical time drift is a continuous and gradual process, and its time drift can be modeled sufficiently relative to the Ref UE sampling period. For eNB1, the parameters for the allowed time drift (e.g., T) drift1MaxThis can be determined in order to specify whether any correction action from Ref UE is required.

[0098] Having different current T drift1 The cross-region of the indicated TOA measurement can be used to further evaluate the stability of the reference time and can also trigger the optimal correction action.

[0099] In this embodiment, Ref UE 500 can be calibrated before use. In LTE, the basic time unit T is used. s = 0.0325 microseconds, because it is the sampling time of the OFDM symbol. The T... s =0.0325 microseconds creates a granularity (accuracy) of 4,875m over a distance, which is relative to T, which can be determined with nanosecond accuracy. ref The accuracy is very poor for values.

[0100] Figure 8 The diagram illustrates an example of the Ref UE calibration process for three eNBs. However, a similar process applies to any number of eNBs.

[0101] At step 800, namely “PRC: Precision Reference Clock”, the time from the precision reference clock T is provided to eNB1, which can be common to eNB. It can be assumed that this requirement can be met during calibration.

[0102] In step 802, namely “eNB1: Synchronize Internal Clock”, the eNB1 internal clock can be synchronized with the PRC. Therefore, the eNB1 internal clock T e1 It is a function of T, that is, T e1 (T). If the PRC is available for the eNB, then essentially the same amount of time is used across the mobile network:

[0103] T e1 (T)=T e2 (T)(Equation 5)

[0104] Without synchronization with the PRC, time T e1 It needs to rely on its own crystal oscillator (or other means) for stability, in which case T e1 The time value can be expressed as T e1 (T e1 Furthermore, relation 5 may not hold true.

[0105] At step 804, namely “eNB1: Transmit TOA Reference Symbol”, the eNB1 broadcasts or transmits a reference symbol, which includes information about the transmission time of the physical reference symbol. In an embodiment, this can be the transmission time from the eNB1 antenna system. In this case, T0(Te1 It can be provided in the form HH:MM:SS:MS:US:NS, and due to the latching process, T0 depends on T. e1 The quality. Due to T0(T) e1 The value represents the physical transmission time, and therefore may require compensation for eNB1 processing and eNB1-specific transmission delays.

[0106] In the next step 806, namely "Ref UE: Synchronize internal clock with eNB1", Ref UE can perform a random access procedure to receive network time. In this way, Ref UE can synchronize its own internal clock T ue Synchronize with the connected eNB1, which means that initially it is function T ue (T e1 ). T e1 Any inaccuracies may affect T ue This step is for calibration. Additionally, Ref UE time drift can be expected, and therefore synchronization may be lost after a period of time.

[0107] T ue (T ue ) = T ue (T e1 (Equation 6)

[0108] If the PRC is available for the Ref UE, the Ref UE time can be a function of time T, as specified in Equation 7, which can be considered typical. When the Ref UE is synchronized with the network, T can be... ue Time drift is compensated periodically.

[0109] T ue (T ue ) = T ue (T e1 ) = T ue (T e1 (T))(Equation 7)

[0110] In step 808, namely “Ref UE: Receive TOA reference symbol from NB1”, Ref UE can receive the reference symbol relative to its own time reference source T. ue To latch its receiving time T1, which means it is a function T1(T ue The Ref UE can take into account the Ref UE processing and transmission delays.

[0111] In step 810, namely “Ref UE: Measure TOA Propagation Delay to eNB1”, Ref UE uses the T0 and T1 values ​​to measure the TOA signal propagation delay to eNB1. The signal propagation delay T...prop1 (eNB1,T e1 ,T ue It is determined by Equation 2, but in the basic time unit T. s The particle size was measured.

[0112] At step 812, namely “Ref UE: Reference delay (distance) to eNB1”, the reference delay for the eNB can be determined as specified by Equation 1.

[0113] Step 814, "Ref UE: Calibrate Ref UE TOA Propagation Delay (Distance) for NB1," describes the process of fine-tuning the TOA accuracy improvement. A correction factor eNB1corr related to the TOA is determined. This correction factor can be added to the TOA propagation delay measurement for a given eNB. This can be illustrated with numerical examples of exemplary data (also...). Figure 9 The figures shown are used for explanation. The non-restrictive values ​​are merely illustrative examples.

[0114] In this example, the Ref UE is fully synchronized with the network time, i.e., T ue (T ue ) = T ue (T e1 This ensures that any initial time drift is compensated.

[0115] Reference signal T0(T e1 The sending time of HH:MM:SS:MS:US:NS is 00:00:00:00:00:00.

[0116] In this example, Ref UE is at a distance D from the eNB antenna system ref1 At (eNB1) = 10000m900, this corresponds to 33,356 microseconds of microwave signal propagation and corresponds to T. ref1 (eNB1)=102,64Ts;00:00:00:00:33:36.

[0117] Ref UE can be in T s 902 resolution latch about T1(T) ue The information, which means T1(T) ue ) = 103T s It can exist with T1(T ue The particle size-related error can be equal to -0.36T. s It can be identified as eNB1corr.

[0118] In the next step, eNB1corr = -0.36T s It can be added to Tue (T ue (Referring to eNB1, in this case it can be denoted as T) ue1 (T ue ):

[0119] T ue1 (T ue ) = T ue (T ue )-eNB1corr(Equation 8)

[0120] Based on Equation 8, any subsequent TOA measurement of eNB1 can be compensated by eNB1corr. As a result, T s Boundary and T ref1 The actual propagation delay alignment determined by (eNB1). T1(T ue Minor differences in the accuracy of the time base in ) can then be detected by the indicated T s The changes are used to transmit signaling, which can be 103T. s (If in Figure 9 (left side) or 104T s (If in Figure 9 (on the right side);

[0121] Furthermore, the additional accuracy of TOA measurements can be achieved by using an orthogonal time reference T. ue1 I(T ue )904 and T ue1 Q(T ue )906 (Offset 0.5T) s This is achieved by ); as can be seen, for T ue1 I(T ue The reference symbol can be found in T1(T ue ) = 104T s It is latched at time, while for T ue1 Q(T ue ), in T1(T ue ) = 103T s hour.

[0122] As a result, it can be 1 / 4T s To allocate T1(T) with the precision of ue This event, for example, can be four times better than a conventional TOA measurement.

[0123] By adding eNB1corr to the time base on the Ref UE side, any changes in the TOA measurement can be detected, implying higher TOA accuracy. In this embodiment, the correction of eNB1corr is static. Additional correction factors can be determined for any other eNB.

[0124] Return to Figure 8 In step 816, namely “Ref UE: Measure reference clock drift for eNB1”, Ref UE measures T drift1 (T e1 ,T ue1 The stability of ). By using T ue1 I(T ue ) and T ue1 Q(T ue (Or, using a more offset reference clock for TOA measurement) can improve TOA accuracy. In this case, a time offset of 8,125 ns can be detected, which is sufficient for mobile network time monitoring and verification. This can also be denoted as T. drift1Max Value, if the measured TOA delay is relative to T ref1 (eNB1) can be used as a trigger if it exceeds this limit.

[0125] In an embodiment, by using more T s Using the offset as a time base at Ref UE can also achieve higher TOA accuracy. This is not technically complicated because the T1 latching process requires multiplication over the offset base time, such as:

[0126] T ue1 I(T ue ) = T ue1 (T ue (Equation 9A)

[0127]

[0128] In the embodiment, once the Ref UE is calibrated, any change in the TOA propagation delay can be determined by the parameters for T1(T). ue )Ref UE T ue Or for T0(T) e1 eNB1 T e1 This is caused by related instability.

[0129] In the embodiment, in eNB1 T e1 (T e1 The instability of ) can affect TOA measurements related to eNB1.

[0130] In the embodiment, in Ref UE T ue (T ue The instability of ) can affect any TOA measurement performed by the Ref UE relative to any other eNB, because the time floor T ue (T ueIt can be public and any corrections added are static, such as Equation 8.

[0131] In normal mobile network operation where the PRC is available, the time base at the eNB is within tolerance, meaning that any Ref UE (or any UE) connected to the network can have accurate and precise time. The UE's timing can be periodically resynchronized to cover any instabilities at the UE's reference time source. However, if the PRC is unavailable for some eNBs, the resynchronization mechanism may give incorrect results.

[0132] Finally, in step 818, the Ref UE TOA measurement can be calibrated using any eNB within the coverage area. The parameter T for eNB1... drift1Max Accuracy / precision can be determined, and if it exceeds a certain limit, it can be used for T. ue or T e1 The trigger for time correction. As explained, higher accuracy can be achieved if orthogonal or similar techniques are used (see Equations 9A and 9B).

[0133] Figure 10 An example activity diagram of a calibrated Ref UE 500 is illustrated. In this example, eNB1 may have lost synchronization with the PRC. However, the PRC may still be available for eNB2 and eNBX. ENB1 operates based on its own internal clock. In an embodiment, once the TOA measurement using the reference signal sent by eNB1 exceeds a given threshold level (such as T...),... drift1Max ), then the Ref UE can detect any reference time drift. This could be because, even though the access node has lost synchronization, its internal clock may still maintain sufficiently accurate time, at least for a period of time. Figure 10 In the example, the time drift of ENB1 may still be within limits, even though it has lost synchronization with the PRC. The Ref UE can determine that the TOA measurement from the eNB is correct, meaning that the conditions in Equations 3 and 4 hold for the eNB. No further action is required from the Ref UE. This state can correspond to Figure 5A and Figure 5B The scene shown.

[0134] about Figure 10 After a given time period, the internal clock of eNB1 may drift beyond the T defined by TOA. drift1Max Threshold. In this case, the Ref UE can detect this state, such as... Figure 11 The NOK state for eNB1 shown is obtained from step 1100. This can correspond to... Figure 6A and Figure 6B The scene shown.

[0135] To pinpoint the source of the problem, the Ref UE can measure the TOA propagation delay of other nearby eNBs (which could be eNB2 and eNBX). As indicated by the OK status from steps 1102 and 1104, these additional TOA measurements are correct in this example. This confirms to the Ref UE that the problem is related to the TOA propagation delay of eNB1. e1 Drift-related. Reference time T at Ref UE. ue That's correct, because T ue It is common to eNB (eNB1corr is a static offset).

[0136] In the embodiment, if better accuracy is required, then eNB1 T e1 Time drift can be assessed as being essentially equal to T. drift1Max Or generally T drift1 The change can be positive or negative, and it can be denoted as + / -T. drift1 .

[0137] In the embodiment, when Ref UE has determined the eNB1 internal clock T e1 When adjustments are needed, it can perform actions such as regarding Figure 12 The actions shown.

[0138] exist Figure 12 In step 1200, namely “Ref UE: Time correction required for eNB1”, if a precise reference time base is available (as previously explained) or T drift1Max Then Ref UE determines the time correction + / -T that may be needed for eNB1. drift1 (It can be an exact value).

[0139] Ref UE requests an RRC connection to eNB1.

[0140] Furthermore, in step 1202, namely “Ref UE: Send eNB time correction”, Ref UE can report to eNB1 that the internal clock of eNB1 needs to be adjusted + / -T. drift1 This means T e1 The time should be changed to T e1 + / -T drift1 .

[0141] In step 1204, namely “eNB1: Resynchronize Internal Clock”, eNB1 is configured to adjust its internal clock to T. e1 + / -T drift1This will also affect any UE connected to that eNB. Therefore, even if a given eNB is operating without a PRC connection, any other UE will receive the corrected time according to the traditional synchronization mechanism.

[0142] In step 1206, namely “Ref UE: Resynchronize Internal Clock”, the Ref UE in the RRC connection state also adjusts its internal clock T. ue (T e1 + / -T drift1 This means that both eNB1 and Ref UE will have a common reference clock for TOA measurements.

[0143] At step 1208, eNB1 transmits a reference signal at time T0. Ref UE receives the signal at step 1210, as at time T1, as previously described. These transmissions occur during the updated internal clock cycles of eNB1 and Ref UE. For Ref UE, this means that the TOA measurement of eNB1 is correct again.

[0144] Ref UE is configured to also continuously measure other TOA measurements to verify that these other measurements are still correct, which confirms that the problem has been resolved via T. e1 The time adjustment has been resolved. If other TOA measurements are normal (ok), the problem is resolved and no further action is required. Synchronization has been restored.

[0145] If the PRC is unavailable or does not exist for a large number of eNBs, then Ref UE can determine the time drift in more than one eNB, as per the information provided. Figure 13 As shown, two NOK states, 1300 and 1302, can be received. This also applies to the Ref UE internal clock T. ue The instability. This situation can be signaled through more than one TOA measurement error; if one eNB is affected, it is a different situation.

[0146] In this scenario, Ref UE can determine which TOA measurements are incorrect and then separately address them via T for the eNB. drift1Max or T drift1 The value is used to evaluate the error / error. Therefore, Ref UE can determine the error / error value for T. ue The time correction can be shown in Equation 10:

[0147] min(T drift1 ,T drift2 (Equation 10)

[0148] Among them, T drift1 、T drift2It refers to the value for different eNBs.

[0149] The proposed solution ensures that changes are implemented in smaller increments, which improves the management of such changes. It can be noted that T ue Changes in this can also affect other TOA measurements. Figure 14 The illustration shows an example of how a change to the reference time at the Ref UE can be implemented (Equation 10). The Ref UE may be in an RRC idle state, or if it is in an RRC connected state, the change can be applied to the received time value, so the current time value may have no effect on these changes.

[0150] After implementing the change in the internal clock reference time of the Ref UE, the Ref UE can be configured to repeat the TOA measurement until the TOA measurement is similar to those from the calibration.

[0151] In an embodiment, in more complex scenarios, a correction can be proposed to any eNB and Ref UE until the result is correct again.

[0152] Therefore, as shown in the example above, the Ref UE can distinguish whether the reference time source needs to be corrected at the eNB or the Ref UE. This is useful when the mobile network needs to operate without PRC access for any reason. This could be in situations where the network uses satellite-based synchronization and the performance of satellite-based synchronization is affected or interfered with by natural phenomena such as solar flares, or when such a system is unavailable.

[0153] As shown in the figure, the proposed solution, for example, does not require complex and expensive equipment related to the PRC in the form of an atomic clock. The Ref UE can be an IoT / LTE-M or broadband UE, and its performance is still sufficient to maintain operation.

[0154] Figure 15 An embodiment is illustrated. The accompanying figure illustrates a simplified example of a device or network entity to which an embodiment of the invention is applied. In some embodiments, the device may be a user equipment (such as Ref UE 500) or part of Ref UE.

[0155] It should be understood that the device is described herein as an example illustrating some embodiments. It will be apparent to those skilled in the art that the device may also include other functions and / or structures, and not all described functions and structures are necessary. Although the device has been described as a single entity, different modules and memories may be implemented in one or more physical or logical entities.

[0156] The example device 500 includes a control circuit 1500 configured to control at least a portion of the operation of the device.

[0157] The device may include a memory 1502 for storing data. Furthermore, the memory may store software 1504 that can be executed by the control circuitry 1500. The memory may be integrated into the control circuitry.

[0158] The device further includes one or more interface circuits 1506 configured to connect the device to other devices and network units or entities in a radio access network, such as access nodes or eNBs.

[0159] In an embodiment, software 1504 may include a computer program that includes program code components adapted to cause the control circuitry 1500 of the device to implement at least some of the embodiments described above.

[0160] Figure 16 An embodiment is illustrated. The accompanying drawing illustrates a simplified example of a device or network entity to which an embodiment of the invention is applied. In some embodiments, the device may be a network element or network entity that acts as a radio access node or eNB 502, or it may be part of a radio access node or eNB.

[0161] It should be understood that the device is described herein as an example illustrating some embodiments. It will be apparent to those skilled in the art that the device may also include other functions and / or structures, and not all described functions and structures are necessary. Although the device has been described as a single entity, different modules and memories may be implemented in one or more physical or logical entities.

[0162] The example device 502 includes a control circuit 1600 configured to control at least a portion of the operation of the device.

[0163] The device may include a memory 1602 for storing data. Furthermore, the memory may store software 1604 that can be executed by the control circuitry 1600. The memory may be integrated into the control circuitry.

[0164] The device further includes one or more interface circuits 1606, 1608 configured to connect the device to other devices and network units or entities in a radio access network, such as a core network and user terminals. These interfaces can provide wired or wireless connectivity.

[0165] In an embodiment, software 1604 may include a computer program that includes program code components adapted to cause the control circuitry 1600 of the device to implement at least some of the embodiments described above.

[0166] The steps and related functions described above and in the accompanying figures are not in an absolute chronological order, and some steps may be performed simultaneously or in a different order than given. Other functions may also be performed between or within steps. Some steps may also be omitted or replaced with corresponding steps.

[0167] The device or controller capable of performing the above steps can be implemented as an electronic digital computer, processing system, or circuit, which may include working memory (random access memory, RAM), a central processing unit (CPU), and a system clock. The CPU may include a set of registers, an arithmetic logic unit, and a controller. The processing system, controller, or circuit is controlled by a sequence of program instructions transferred from RAM to the CPU. The controller may contain multiple microinstructions for basic operations. The implementation of the microinstructions may vary depending on the CPU design. The program instructions may be encoded in a programming language, which may be a high-level programming language (such as C, Java, etc.) or a low-level programming language (such as machine language or assembler). The electronic digital computer may also have an operating system that provides system services for computer programs written with the program instructions.

[0168] As used in this application, the term "circuit" means all of the following: (a) a hardware circuit implementation, such as an implementation employing only analog and / or digital circuits; and (b) a combination of circuitry and software (and / or firmware), such as (if applicable): (i) a combination of processors; or (ii) a portion of processor / software, including a digital signal processor, software, and memory, which work together to enable the device to perform various functions; and (c) a circuit, such as a microprocessor or a portion thereof, which requires software or firmware to function, even if such software or firmware does not exist physically.

[0169] This definition of "circuit" applies to all uses of the term in this application. As a further example, as used in this application, the term "circuit" will also cover only the implementation of a processor (or processors) or a portion thereof and its accompanying software and / or firmware. The term "circuit" will also cover (for example, and if applicable to a particular element) baseband integrated circuits or application processor integrated circuits for mobile phones, or similar integrated circuits in servers, cellular network devices, or other network devices.

[0170] An embodiment provides a computer program embodied on a distributed medium, which includes program instructions that, when loaded into an electronic device, are configured to control the device to perform the embodiments described above.

[0171] Computer programs can take the form of source code, object code, or some intermediate form, and they can be stored on some kind of medium, which can be any entity or device capable of carrying the program. Such media include, for example, recording media, computer memory, read-only memory, and software distribution packages. Depending on the required processing power, a computer program can be executed on a single electronic digital computer, or it can be distributed across multiple computers.

[0172] The device can also be implemented as one or more integrated circuits, such as application-specific integrated circuits (ASICs). Other hardware embodiments are also possible, such as circuits constructed from separate logic components. A mixture of these different implementations is also possible. When choosing an implementation method, those skilled in the art will consider, for example, the requirements set for the device's size and power consumption, the required processing power, manufacturing costs, and production volume.

[0173] In one embodiment, an apparatus includes: at least one processor; and at least one memory including computer program code configured, together with the at least one processor, to cause the apparatus to at least: store information about a reference propagation delay between the apparatus and one or more radio access nodes; control the reception of a reference signal from the one or more radio access nodes, the reference signal including information about the transmission time of the signal; determine the reception time of the reference signal; determine the propagation delay of the reference signal based on the time difference between the reception time and the transmission time; and determine the correctness of the time reference of the apparatus and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay.

[0174] In one embodiment, an apparatus includes: at least one processor; and at least one memory including computer program code, the at least one memory and the computer program code being configured, together with the at least one processor, to cause the apparatus to at least: control the transmission of a reference signal to a user terminal, the reference signal including information about the timing of the transmission of the signal; control the reception of an instruction from the user terminal, the instruction including information about a correction of a time reference for the apparatus; and correct the time reference of the apparatus based on the instruction.

[0175] In one embodiment, a non-transitory computer-readable medium includes program instructions for causing a device to perform at least the following operations: storing information about a reference propagation delay between the device and one or more radio access nodes; controlling the reception of a reference signal from the one or more radio access nodes, the reference signal including information about the transmission time of the signal; determining the reception time of the reference signal; determining the propagation delay of the reference signal based on the time difference between the reception time and the transmission time; and determining the correctness of the time reference of the device and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay.

[0176] In one embodiment, a non-transitory computer-readable medium includes program instructions for causing a device to perform at least the following operations: controlling the transmission of a reference signal to a user terminal, the reference signal including information about the time of transmission of the signal; controlling the reception of an instruction from the user terminal, the instruction including information about the correction of a time reference for the device; and correcting the time reference of the device based on the instruction.

[0177] It will be apparent to those skilled in the art that the concept of this invention can be implemented in various ways as technology advances. The invention and its embodiments are not limited to the examples described above, but can be varied within the scope of the claims.

Claims

1. A user equipment, comprising: Components (1500, 1506) for storing information about the reference propagation delay between the user equipment and one or more radio access nodes; Components (1500, 1506) for controlling the reception of reference signals from one or more radio access nodes, wherein the reference signals include information about the transmission time of the reference signals; Components (1500, 1504) used to determine the reception time of the reference signal; Components (1500, 1504) for determining the propagation delay of the reference signal based on the time difference between the receiving time and the transmitting time; Components (1500, 1504) for determining the correctness of the time reference of the user equipment and the one or more radio access nodes based on the determined propagation delay and the stored propagation delay; A component for determining that the time base of the user equipment is incorrect if the determined propagation delay and the stored propagation delay associated with more than one radio access node are not equal; and A component for determining that the time base of a radio access node is incorrect if the determined propagation delay and the stored propagation delay associated with one of the one or more radio access nodes are not equal, and the determined propagation delay and the stored propagation delay associated with at least one of the other one or more radio access nodes are equal with a given margin.

2. The user equipment according to claim 1, further comprising: A component used to determine corrections for incorrect time bases.

3. The user equipment according to claim 1, further comprising: Components for controlling the transmission of an indication to one of the one or more radio access nodes, wherein the indication includes information regarding the correction of the incorrect time reference.

4. The user equipment according to claim 1, further comprising: A component for correcting the time reference of the user equipment based on the determined correction.

5. A method performed by a user equipment, comprising: Store (300) information about the reference propagation delay between the user equipment and one or more radio access nodes; Control (302) receives a reference signal from one or more radio access nodes, the reference signal including information about the transmission time of the reference signal; Determine the reception time of the reference signal described in (304); Based on the time difference between the receiving time and the sending time, the propagation delay of the reference signal is determined (306); Based on the determined propagation delay and the stored propagation delay, determine (308) the correctness of the time reference of the user equipment and the one or more radio access nodes; If the determined propagation delay and the stored propagation delay associated with more than one radio access node are not equal, then the time base of the user equipment is determined to be incorrect. as well as If the determined propagation delay and the stored propagation delay associated with one of the one or more radio access nodes are not equal, and the determined propagation delay and the stored propagation delay associated with at least one of the other one or more radio access nodes are equal with a given margin, then the time base of the radio access node is determined to be incorrect.

6. The method of claim 5, further comprising: Determine corrections for incorrect time bases.

7. The method of claim 5, further comprising: The control sends an instruction to one of the one or more radio access nodes, the instruction including information regarding correction for the incorrect time base.

8. The method of claim 5, further comprising: Based on the determined correction, the time base of the user equipment is corrected.

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