WO2024216559A1

WO2024216559A1 - Timing advance determination

Info

Publication number: WO2024216559A1
Application number: PCT/CN2023/089357
Authority: WO
Inventors: Mads LAURIDSEN; Rafhael MEDEIROS DE AMORIM; Jing Yuan Sun; Ping Yuan; Srinivasan Selvaganapathy; Jeroen Wigard
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Priority date: 2023-04-19
Filing date: 2023-04-19
Publication date: 2024-10-24
Anticipated expiration: 2025-10-19

Abstract

Embodiments of the present disclosure relate to timing advance (TA) determination. A terminal device obtains a configuration for determining a TA after performing a positioning measurement; and obtains, after performing the positioning measurement, a TA value based on the configuration. In this way, a way of determining a TA after a positioning measurement can be defined or configured, such that the terminal device is aware of how to determine the TA for subsequent transmission (s).

Description

TIMING ADVANCE DETERMINATION

FIELD

Various example embodiments relate to the field of telecommunication and in particular, to a terminal device, a network device, methods, apparatuses and a computer readable storage medium for timing advance determination.

BACKGROUND

In a communication system, a network device may transmit timing advance (TA) commands to a terminal device to align uplink (UL) transmissions to downlink (DL) transmissions timing at the network device. With the TA, different propagation delays for various terminal devices can be considered and compensated. Thus the TA determination needs to be well studied in order to mitigate or minimize uplink interference.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for TA determination.

In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: obtain a configuration for determining a timing advance, TA, after performing a positioning measurement; and obtain, after performing the positioning measurement, a TA value based on the configuration.

In a second aspect, there is provided a network device. The network device comprises at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: transmit, to a terminal device, a configuration for determining a timing advance, TA, after performing a positioning measurement; and receive, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.

In a third aspect, there is provided a method. The method comprises obtaining, at a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and obtaining, after performing the positioning measurement, a TA value based on the configuration.

In a fourth aspect, there is provided a method. The method comprises transmitting, at a network device and to a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and receiving, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.

In a fifth aspect, there is provided an apparatus comprising: means for obtaining, at a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and means for obtaining, after performing the positioning measurement, a TA value based on the configuration.

In a sixth aspect, there is provided an apparatus comprising: means for transmitting, at a network device and to a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and means for receiving, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.

In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to any one of the above third to fourth aspect.

In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: obtain, at a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and obtain, after performing the positioning measurement, a TA value based on the configuration.

In a ninth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus at least to: transmit, at a network device and to a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and receive, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration

In a tenth aspect, there is provided a terminal device comprising: obtaining circuitry configured to obtain a configuration for determining a timing advance, TA, after a positioning measurement; and obtaining circuitry configured to obtain, after performing the positioning measurement, a TA value based on the configuration.

In an eleventh aspect, there is provided a network device comprising: transmitting circuitry configured to transmit, at a network device and to a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and receiving circuitry configured to receive from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

Fig. 1A illustrates an example uplink-downlink timing relation;

Fig. 1B illustrates an example communication system in which embodiments of the present disclosure may be implemented;

Fig. 2 illustrates an example of a process for TA determination according to some embodiments of the present disclosure;

Fig. 3 illustrates an example of a process for obtaining a TA value for a subsequent transmission according to some embodiments of the present disclosure;

Fig. 4 illustrates another example of a process for obtaining a TA value for a subsequent transmission according to some embodiments of the present disclosure;

Fig. 5 illustrates an example of a process of a terminal device obtaining a TA value for a subsequent transmission according to some embodiments of the present disclosure;

Fig. 6 illustrates a flowchart of a method implemented at a terminal device according to some embodiments of the present disclosure;

Fig. 7 illustrates a flowchart of a method implemented at a network device according to some embodiments of the present disclosure;

Fig. 8 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 9 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) , that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

As mentioned above, the UL transmissions may be aligned to DL transmissions timing at the network device in order to mitigate the uplink interference. Fig. 1A illustrates an example uplink-downlink timing relation. As can be seen from Fig. 1A, a transmission of the uplink radio frame number i from UE may start T_TA seconds before the start of the corresponding downlink radio frame i at the UE.

Conventionally, T_TA may be determined based on a fixed timing offset N_TA, offset and a network-controlled component N_TA. DL and UL may be frame aligned at an uplink time synchronization reference point (RP) with an offset given by N_TA, offset. The N_TA, offset may be determined based on parameters conveyed by the network. The N_TA may be dynamically adjusted. For example, the N_TA may be adjusted according to the following equation (1) and wherein T_A denotes a TA index indicated by a TA command (TAC) .
N_TA=N_TA-old+ (T_A-31) ·16·64/2^μ (1)

In a non-terrestrial network (NTN) , the UE may pre-compensate the T_TA by considering a common TA corresponding to a round trip time (RTT) between the RP and the NTN payload, UE position, and the satellite position through the satellite ephemeris. This pre-compensation may be needed, when the NTN system is operating over low-earth orbit satellites, which move about 28,000 km/h relative to Earth. The pre-compensation may be performed based on the UE being aware of the target satellite’s position (for example, via satellite assistance information broadcast in system information broadcast (SIB) 31 –see 3GPP TS 36.331) and the UE’s own position.

The UE may perform a global navigation satellite system (GNSS) measurement to determine a UE position and then determine a distance between the UE and the satellite and how the distance will change during a transmission, so as to determine exact timings of UL transmissions. In addition to the satellite-UE distance, the UE may also compensate for the delay on the feeder link, which is the link between the satellite and the eNB on Earth in Rel-17 and Rel-18, because the satellite is transparent/bent pipe i.e. acting as a relay without an eNB onboard.

For example, as defined in 3GPP TS 36.211, T_TA may be determined based on and details are omitted herein. As can be seen from the equation, two additional NTN-specific componentsandare considered in the determination of the T_TA. Themay be used for compensation of a common delay between the RP and the serving satellite. Themay be used for compensation of a transmission delay between the serving satellite and the UE. Themay be a UE service link-specific component related to the distance between the UE and the serving satellite.

However, in 3GPP Rel-17 and Rel-18, it is assumed that the UE is not able to perform a GNSS measurement and NTN communication simultaneously. Specifically, it is agreed in Rel-17 that the UE will move to a radio resource control (RRC) idle state when it needs to perform a GNSS measurement. Such a need is known to the UE based on the UE reporting the remaining GNSS validity duration. However, moving to the RRC idle state creates overhead in terms of connection setup signaling if the UE has a long connection and is non-stationary i.e., it may need to move to the RRC idle state to perform GNSS measurements multiple times.

Moreover, it is agreed in Rel-18 that the eNB can trigger the UE to perform a GNSS measurement, e.g., when the current GNSS validity duration is about to expire. It is agreed that the eNB can at least aperiodically trigger the UE to perform a GNSS measurement. It is also agreed that for a GNSS measurement in a RRC connected state, if the eNB aperiodically triggers connected UE to make a GNSS measurement, the UE can re-acquire a GNSS position fix with a gap. The gap may be referred to as a GNSS measurement gap.

Therefore, based on the above assumption, the UE may need to communicate or re-communicate with the NTN system after completing a GNSS measurement. Moreover, the UE may need a suitable TA for subsequent transmission (s) to the NTN system since the current/previous/old TA may be inappropriate due to, for example, UE movement, satellite movement, inaccuracy in the TA common function used for determineand/or a propagation environment change.

For example, after the GNSS measurement is completed, the UE may be unaware of how to adjust, determine or obtain the N_TA for the subsequent transmission (s) . This may be due to a fact that the TAC, which is used for determining the N_TA, does not specify the reason why it is transmitted. As an example, the network may transmit the TAC to the terminal device to compensate for incorrectcaused by an out-of-date UE position. As another example, the network may transmit the TAC to the terminal device to compensate for incorrectcaused due to errors in the common TA calculation. As yet another example, the network may transmit the TAC to the terminal device to create an artificial latency in an NTN link.

According to embodiments of the present disclosure, there is providing a solution for TA determination. In this solution, a terminal device obtains a configuration for determining a TA after performing a positioning measurement. The terminal device further obtains, after performing the positioning measurement, a TA value based on the configuration. With the configuration for determining a TA after a positioning measurement, the terminal device can be aware of how to obtain the TA after the positioning measurement. Thus, the TA determination after a positioning measurement can be defined or configured.

Principle and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, it is to be noted that these embodiments are illustrated as examples and not intended to limit scope of the present application in any way.

Reference is now made to Fig. 1B, which illustrates an example communication system 100 in which embodiments of the present disclosure may be implemented. As illustrated in Fig. 1B, the communication system 100 may comprise a terminal device 110, a network device 120, a gateway 130, a data network 140 and a non-terrestrial device 150.

In some embodiments, in a transparent (bent-pipe) case, the network device 120 is on Earth and in or near the gateway 130. The terminal device 110 may communicate with the network device 120 via a service link 151 between the non-terrestrial device 150, e.g., a satellite and the terminal device 110 and a feeder link 152 between the non-terrestrial device 150 and the network device 120 on Earth. There may be a link connection 153 between the gateway 130 and the data network 140.

Alternatively, in a non-transparent (regenerative) case, which is not shown herein, the network device 120 may correspond to or be included in the non-terrestrial device 150. The terminal device 110 may communicate with the network device 120 via the service link 151. The network device 120 may communicate with the gateway 130 via the feeder link 152. There may be a link connection 153 between the gateway 130 and the data network 140. The network device 120 may access the data network 140 via the feeder link 152, the gateway 130, and/or the link connection 153 between the gateway 130 and the data network 140.

It is to be understood that in Fig. 1B, the number of network devices and terminal devices is only for the purpose of illustration without suggesting any limitations. The communication system 100 may include any suitable number of network devices and terminal devices adapted for implementing embodiments of the present disclosure.

Communications in the communication system 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , Frequency Division Duplex (FDD) , Time Division Duplex (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiple (OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

In the communication system 100, the terminal device 110 obtains a configuration for determining a TA after performing a positioning measurement. In some embodiments, the terminal device 110 may obtain the configuration from the network device 120. Alternatively or additionally, the configuration may be defined in the specification, i.e., hard coded. The terminal device 110 further obtains, after performing the positioning measurement, a TA value based on the configuration. In some embodiments, the terminal device 110 may determine the TA value based on the configuration. Alternatively, the terminal device 110 may perform a random access and the network device 120 may transmit a TA value in a random access response to the terminal device 110.

Reference is now made to Fig. 2, which shows an example of a process 200 for TA determination according to an embodiment of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to Fig. 1B. The terminal device 110 and the network device 120 may be involved in the process 200 for the purpose of illustration.

In the process 200, the network device 120 may transmit 205 a configuration 210 for determining a TA after a positioning measurement. The terminal device 110 may receive 215 the configuration 210. Alternatively, the configuration 210 may be defined by the specification and hard coded in the terminal device 110. In both cases, the terminal device 110 obtains 217 the configuration 210 for determining a TA after a positioning measurement.

The configuration 210 may define a way or rule to obtain a TA after a positioning measurement by the terminal device 110. The term “TA” herein may refer to a timing advance that an uplink radio frame shall start before a corresponding downlink radio frame at the terminal device 110. The uplink radio frame and the corresponding downlink radio frame are aligned at the uplink time synchronization RP with a fixed offset. For example, as illustrated by Fig. 1A, the TA may refer to T_TA in seconds.

The positioning measurement may comprise any suitable positioning procedure. In some embodiments, the positioning measurement may comprise a global navigation satellite system (GNSS) measurement. Alternatively, the positioning measurement may comprise a 3GPP-based positioning procedure, for example, a multi-cell round trip time (RTT) measurement and/or an observed time difference of arrival (OTDOA) measurement.

The terminal device 110 performs 220 a positioning measurement, for example, a GNSS measurement and get a new position of the terminal device 110. In some embodiments, the positioning measurement may be triggered by the network device 120 via a trigger command. For example, in Rel-18, it has been agreed that the eNB can trigger the UE to perform a GNSS measurement, e.g., when the current GNSS validity duration is about to expire. Alternatively or additionally, the positioning measurement may be performed autonomously by the terminal device 110. The terminal device 110 may autonomously update its position fix by performing a positioning measurement.

After the positioning measurement, the terminal device 110 obtains 245 a TA value based on the configuration 210. The term “TA value” herein may refer to a value or component for determining the TA. As an example, the TA value may be the N_TA as defined in 3GPP TS 36.211. As another example, The TA value may be a newly-defined component other than the N_TA for determining the TA.

In some embodiments, the configuration 210 may indicate the terminal device 110 to perform a random access to acquire a new TA value. As illustrated in Fig. 2, the terminal device 110 may transmit 230 a random access channel 235 to the network device 120. The network device 120 may receive 240 the random access channel and transmit a random access response (RAR) to the terminal device 110. The new TA value may be indicated in the RAR. The random access may comprise a contention-free random access (CFRA) or a contention-based (CBRA) random access.

In some embodiments, if CFRA resources are pre-configured and a measurement gap is used for performing the positioning measurement, a MAC command may indicate whether the resources can be used after the measurement gap or just before start of the measurement gap. Alternatively, a MAC command may indicate a release of the CFRA resources pre-configured at any time. In such case, the terminal device 110 may switch to the CBRA instead of the CFRA.

Alternative to the random access, the configuration 210 may indicate the terminal device 110 to obtain 245 a TA value by other ways. The configuration 210 may indicate a way or rules of obtaining the TA value by the terminal device 110. The details will be described hereafter. Based on the obtained TA value, the terminal device 110 may determine a new TA for the subsequent transmission (s) and transmit 250 a transmission 255 using the obtained TA value to the network device 120. The network device 120 may receive 260 the transmission 255 which was transmitted with the new TA.

In some embodiments, the configuration 210 may indicate a position threshold. The position threshold may be associated with a position change of the terminal device 110. As an example, the configuration 210 may define or indicate a value of the position threshold directly. As another example, a value of the position threshold may be pre-defined, e.g., defined in the specification or hard coded in the terminal device 110, and the configuration 210 may indicate the terminal device 110 to use the position threshold for obtaining a TA value.

The terminal device 110 may obtain 245 the TA value based on a comparison between the position threshold and a difference associated with the position change of the terminal device 110. In some embodiments, the difference may comprise a geometrical difference between a first/old position prior to the positioning measurement and a second/new position determined from the positioning measurement.

The terminal device 110 may determine the geometrical difference based on a difference or distance between the first/old position and the second/new position. As an example, the terminal device 110 may determine the difference or distance between the first/old position and the second/new position as the geometrical difference. As another example, the terminal device 110 may perform a statistical analysis of the difference or difference between the first/old position and the second/new position to determine the geometrical difference.

Alternatively or additionally, the difference may comprise a time difference between a first time adjustment value determined based on the first/old position and a second time adjustment value determined based on the second/new position. The term “time adjustment value” herein may refer to any adjustment value associated with the position of the terminal device suitable for determining the TA. For example, the time adjustment value may beas defined in 3GPP TS 36.211.

In some embodiments, based on determining that the difference, e.g., the geometrical difference and/or the time difference, is above (or equal to) the position threshold, the terminal device 110 may determine the TA value by adjusting a previous/current/old TA value to be a new TA value that is below a network-configured threshold value. Alternatively or additionally, the terminal device 110 may determine the TA value by adjusting the previous TA value with a network-configured maximum value. For example, the terminal device 110 may adjust the previous TA value with a network-configured or pre-defined x seconds. As an example, based on determining that the difference is above the position threshold, the terminal device 110 may assume that the previous TA value is not applicable for determining the TA anymore, and the previous TA value needs to be updated or adjusted.

Alternatively, the terminal device 110 may determine a first fraction of a previous TA value as the TA value, and the first fraction may range from zero to one. The first fraction may be network-configured or pre-defined. For example, the terminal device 110 may determine a fraction x of N_TA as the new TA value, and x may be 0, 0.5, 0.7 or 1, etc.

Alternatively, the terminal device 110 may determine the TA value based on omitting a number of TACs last received from the network device 120. As described above, the N_TA may be accumulatively adjusted based on a TA index, T_A, indicated in a TAC. In other words, the TA value, e.g., N_TA, may be accumulatively adjusted based on a sequence of TACs. In some embodiments, the terminal device 110 may omit or drop a number of TACs last received from the network device 120 based on an assumption that the number of last received TACs was most likely transmitted for compensating for the incorrect UE position.

The number of omitted or dropped TACs may be network-configured or pre-defined. As an example, all or a portion of TACs that are received since the last positioning measurement may be omitted in determining the new TA value. In some embodiments, the number of omitted or dropped TACs may be associated with the number of TACs received within a time window T. For example, the number of omitted or dropped TACs may be at least a portion of TACs received within the time window T.

In some embodiments, based on determining that the difference, e.g., the geometrical difference and/or the time difference is above the position threshold, the terminal device 110 may perform a random access to acquire a new TA value for determining the TA for subsequent transmission (s) .

In some embodiments, based on determining that the difference associated with the position change of the terminal device 110 is above the position threshold, the terminal device 110 may further reset a time alignment timer (TAT) corresponding to the previous TA value. The TAT may be used for controlling how long one or more serving cells are considered to be uplink time aligned. When the TAT is reset, the corresponding previous TA value may be considered to be no longer applicable.

Alternatively, based on determining that the difference associated with the position change of the terminal device 110 is above the position threshold, the terminal device 110 may continue running the TAT corresponding to the previous TA value. In this case, the one or more serving cells may be considered as uplink time aligned until expiry of the TAT.

In some embodiments, based on determining that the difference associated with the position change of the terminal device 110 is below (or equal to) the position threshold, the terminal device 110 may determine a second fraction of the previous TA value as the TA value, wherein the second fraction ranges from zero to one. The second fraction may be network-configured or pre-defined. For example, the terminal device 110 may keep the previous/current TA value for determining the TA for subsequent transmission (s) . Similarly, the terminal device 110 may further reset the TAT corresponding to the previous TA value or continue running the TAT corresponding to the previous TA value.

In some embodiments, alternatively or in addition to the position threshold, the configuration 210 may indicate a validity threshold. The validity threshold may be associated with a validity duration (or age) of satellite assistance information. The term “satellite assistance information” may refer to any suitable satellite information associated with determination of the TA. In some embodiments, the satellite assistance information may comprise ephemeris that impacts theAlternatively or additionally, the satellite assistance information may comprise a common TA of system information broadcast (SIB) 31 that impacts theSimilar to the position threshold, the configuration 210 may indicate the validity threshold in different ways and the details are omitted herein.

The terminal device 110 may obtain 245 the TA value based on a comparison between the validity threshold and a duration for which the terminal device 110 applies the satellite assistance information (before and after the positioning measurement) . In some embodiments, the terminal device 110 may determine the duration for which the terminal device 110 applies the satellite assistance information based on a difference between an epoch time of the satellite assistance information and a current or present time.

In some embodiments, based on determining that the duration for which the terminal device 110 applies the satellite assistance information is below (or equal to) the validity threshold, the terminal device 110 may determine the TA value based on omitting a number of or a fraction of TACs last received from the network device 120. As an example, based on determining that the duration is below the validity threshold, the terminal device 110 may assume that the satellite assistance information is still relatively new and the number of TACs last received within a time window T is not needed for adjusting the TA. Alternatively, based on determining that the duration is below (or equal to) the validity threshold, the terminal device 110 may perform a random access to acquire the TA value for determining the TA for subsequent transmission (s) .

In some embodiments, based on determining that the duration for which the terminal device 110 applies the satellite assistance information is above (or equal to) the validity threshold, the terminal device 110 may determine the TA value based on keeping a number of or a fraction of TACs last received from the network device 120. As an example, based on determining that the duration is above the validity threshold, the terminal device 110 may assume that the satellite assistance information is relatively old and the number of TACs last received within a time window T is useful for adjusting the TA. Alternatively, based on determining that the duration is above (or equal to) the validity threshold, the terminal device 110 may perform a random access to acquire the TA value for determining the TA for subsequent transmission (s) .

In some embodiments, the configuration 210 may indicate that at least one TAC received from the network device 120 is persistent for determining the TA value after the positioning measurement. Based on this configuration 210, the persistent TAC (s) may not be dropped or omitted in the determination of the TA. Note that, the indication that the persistent TAC (s) shall not be dropped may be independent from other rules of obtaining the TA value. For example, the terminal device 110 may determine to drop last received x TACs for determining the TA value based on the configuration 210. In the meantime, one of the TACs to be dropped is indicated to be persistent for determining the TA value. In such case, the terminal device 110 may drop the TACs excluding the persistent TAC.

In some embodiments, the persistence of TAC (s) may be indicated by a flag in the TAC (s) . For example, the terminal device 110 may receive a TAC with a flag indicating that the TAC is persistent for determining the TA value. In other words, the indication of a persistent TAC may be provided as part of the TAC itself, and the indication to omit or not omit the persistent TAC may be part of the configuration 210.

In some embodiments, the configuration 210 may indicate determining a third fraction of a previous TA value as the TA value, and wherein the third fraction ranges from zero to one. For example, the configuration 210 may indicate scaling the N_TA with a fraction x for the subsequent transmission (s) . Note that, in these embodiments, the configuration 210 may not indicate any threshold as described above. Instead, the configuration 210 may indicate the terminal device 110 to determine the TA value using the third fraction of the previous TA value directly. Moreover, the first fraction, second fraction and third fraction may be the same or different depending on use cases.

In some embodiments, the configuration 210 may indicate one or more of the position threshold, the validity threshold, and rules of obtaining the TA value as described above. The configuration 210 may be transmitted or indicated in various signaling. In some embodiments, the terminal device 110 may receive the configuration 210 by receiving a trigger command for the positioning measurement. Alternatively or additionally, the terminal device 110 may receive the configuration 210 by receiving a media access control (MAC) control element (CE) . Alternatively or additionally, the terminal device 110 may receive the configuration 210 by receiving a radio resource control (RRC) configuration. For example, the configuration 210 may be indicated in a trigger command for an aperiodic GNSS measurement and the trigger command may be provided in a MAC CE or RRC configuration.

Alternatively or additionally, the terminal device 110 may receive the configuration 210 by receiving a system information broadcast (SIB) . Alternatively or additionally, the terminal device 110 may receive the configuration 210 by receiving an active configuration. Alternatively or additionally, the terminal device 110 may receive the configuration 210 by receiving an activation of a pre-configured configuration. As an example, the pre-configured configuration may be indicated in a SIB or RRC configuration.

Alternatively or additionally, the terminal device 110 may receive the configuration 210 by receiving a measurement gap configuration for the positioning measurement. For example, a GNSS measurement gap configuration may comprise the configuration 210 which defines a way to obtain the TA value for determining the TA for subsequent transmission (s) . The GNSS measurement gap configuration may comprise information about the N_TA changes and conditions for triggering an RA as discussed above.

With the configuration 210, the terminal device 110 can be aware of a way to obtain a TA after the positioning measurement. The terminal device 110 can understand how to determine, adjust or acquire the TA for subsequent transmission (s) after the positioning measurement.

In a case where the network device 120 transmits the configuration 210 to the terminal device 110, the network device 120 can be enabled to at least partially control the TA that the terminal device 110 will apply after the positioning measurement. In some embodiments, the network device 120 can be enabled to control whether the terminal device 110 will perform a random access after the positioning measurement to acquire a new TA value or update/reuse the previous TA value for determining the TA. In this way, a trade-off between the RA load or signalling overhead and uplink interference due to an incorrect TA can be achieved.

Fig. 3 illustrates an example of a process 300 of for obtaining a TA value for a subsequent transmission according to some embodiments of the present disclosure. It is noted that the process 300 can be deemed as a more specific example of the process 200. It would be appreciated that the process 300 may be applied to the communication system 100 of Fig. 1B and any other similar communication scenarios.

As shown in Fig. 3, the network device 120 may transmit 305, to the terminal device 110 a configuration 310 for determining a TA after a positioning measurement. The terminal device 110 may receive 315 the configuration 310. The configuration 310 may be an example of the configuration 210 described with reference to Fig. 2.

The network device 120 may transmit 320, to the terminal device 110, an activation 325 of the configuration 310 and the terminal device 110 may receive 330 the activation 325. The network device 120 may transmit 335, to the terminal device 110, a trigger command 340 for a positioning measurement. The terminal device 110 may receive 345 the trigger command 340 and perform 347 the positioning measurement. After the positioning measurement, the network device 120 may determine 350 whether to perform a random access or adjust a previous/current TA based on the configuration 310.

As an example, the configuration 310 may indicate the terminal device 110 to transmit 355 a random access channel 360 to the network device 120. The network device 120 may receive 365 the random access channel 360 and transmit 367 an RAR 368 indicating a TA value to the terminal device 110. The terminal device 110 may receive 369 the RAR 368 and obtain 370 the TA value from the RAR 368. The terminal device 110 may use the obtained TA value to determine a TA for subsequent transmission (s) . For example, the terminal device 110 may determine the TA according to the equation (1) as discussed above. Then the terminal device 110 may transmit 375, to the network device 120, a transmission 380 using the obtained TA value. The network device 120 may receive 385 the transmission 380 that was transmitted based on the TA determined from the obtained TA value.

Fig. 4 illustrates another example of a process for obtaining a TA value for a subsequent transmission according to some embodiments of the present disclosure. It is noted that the process 400 can be deemed as a more specific example of the process 200. It would be appreciated that the process 400 may be applied to the communication system 100 of Fig. 1B and any other similar communication scenarios.

As shown in Fig. 4, the network device 120 may transmit 405, to the terminal device 110 a configuration 410 for determining a TA after a positioning measurement. The terminal device 110 may receive 415 the configuration 410. The configuration 410 may be an example of the configuration 210 described with reference to Fig. 2.

The terminal device 110 may trigger 420 the positioning measurement autonomously and activate 425 the configuration 410. The terminal device 110 may determine 430, after performing the positioning measurement, whether to perform a random access or adjust a previous/current TA based on the configuration 410.

As an example, the configuration 410 may indicate the terminal device 110 to transmit 435 a random access channel 440 to the network device 120. The network device 120 may receive 445 the random access channel 440 and transmit an RAR indicating a TA value to the terminal device 110. The terminal device 110 may obtain 450 the TA value from the RAR and transmit 455, to the network device 120, a transmission 460 using the obtained TA value. The network device 120 may receive 465 the transmission 460 that was transmitted based on the TA determined from the obtained TA value.

Fig. 5 illustrates an example of a process 500 of a terminal device obtaining a TA value for a subsequent transmission according to some embodiments of the present disclosure. The process 500 may be performed by the terminal device 110 in the communication system 100 of Fig. 1B or any other similar communication devices. For the purpose of illustration, the process 500 will be described with reference to Fig. 1B.

As illustrated in Fig. 5, at block 501, the terminal device 110 may receive a configuration for determining a TA after a positioning measurement. At block 502, the terminal device 110 may perform the positioning measurement, e.g., a GNSS measurement autonomously or in response to a trigger command.

After performing the positioning measurement, the terminal device 110 may obtain a TA value for determining the TA based on the received configuration. As discussed above, the configuration may indicate various thresholds and/or rules regarding UE behaviour after the positioning measurement. Examples of the UE behaviour are illustrated in Fig. 5 for the purpose of illustration.

As illustrated in Fig. 5, in some embodiments, at block 510, the terminal device 110 may determine whether the network device 120 indicates keeping a previous or old N_TA (also denoted by N_TA) in the configuration. If yes, the terminal device 110 may determine, at block 513, the old N_TA as the N_TA for determining the T_TA for subsequent transmission (s) and communicate with the network using the determined T_TA. If no, the terminal device 110 may determine, at block 511, whether the network device 120 indicates keeping a fraction x of the old N_TA.

If yes, the terminal device 110 may determine, at block 513, a scaled N_TA*x as the N_TA for determining the T_TA for subsequent transmission (s) and communicate with the network using the determined T_TA. If no, the terminal device 110 may determine, at block 512, whether the network device 120 indicates setting the N_TA to zero in the configuration. If yes, the terminal device 110 may determine, at block 513, N_TA=0 for determining the T_TA for subsequent transmission (s) and communicate with the network using the determined T_TA. If no, the terminal device 110 may perform a CFRA or a CBRA to acquire the N_TA for determining the T_TA for subsequent transmission (s) .

Alternatively, at block 520, the terminal device 110 may determine whether the network device 120 indicates performing an RA in the configuration. If yes, the terminal device 110 may perform, at block 521, a CFRA or CBRA to acquire the N_TA for determining the T_TA for subsequent transmission (s) . If no, the terminal device 110 may use, at block 533, the old N_TA for determining the T_TA for subsequent transmission (s) and communicate with the network using the determined T_TA.

Alternatively, at block 530, the terminal device 110 may receive a distance threshold in the configuration provided by the network device 120. The distance threshold may be an example of the position threshold as described above with reference to Fig. 2. At block 531, the terminal device 110 may determine whether the distance between an old position prior to the positioning measurement (e.g., an old GNSS position) and a new position determined from the positioning measurement (e.g., a new GNSS position) is above the distance threshold.

If yes, the terminal device 110 may perform, at block 532, one of a CFRA, a N_TA adjustment no larger than a network-configured threshold, or a N_TA adjustment based on omitting last X received TACs (within a time window T) . If no, the terminal device 110 may use, at block 533, the old N_TA for determining the T_TA for subsequent transmission (s) and communicate with the network using the determined T_TA.

Alternatively, at block 540, the terminal device 110 may receive a timing advance threshold in the configuration provided by the network device 120. The timing advance threshold may be an example of the position threshold as described above with reference to Fig. 2. At block 541, the terminal device 110 may determine whether the difference between an old TA (or) prior to the positioning measurement and a new TA (or ) determined from the positioning measurement is above the timing advance threshold.

Alternatively, at block 550, the terminal device 110 may receive a duration threshold for SIB31 in the configuration provided by the network device 120. The duration threshold may be an example of the validity threshold as described above with reference to Fig. 2. At block 551, the terminal device 110 may determine whether the difference between a current time and an epoch time of SIB31 indicating the satellite assistance information is above the duration threshold.

If yes, i.e., the satellite assistance information is considered as relatively new, the terminal device 110 may perform, at block 552, a N_TA adjustment based on omitting last X or all received TACs (within a time window T) . If no, i.e., the satellite assistance information is considered as relatively old, the terminal device 110 may perform, at block 553, a N_TA adjustment based on keeping last X or all received TACs (within a time window T) .

Fig. 6 illustrates a flowchart of an example method 600 implemented at a terminal device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 600 will be described from the perspective of the terminal device 110 with reference to Fig. 1B.

At block 610, the terminal device 110 obtains a configuration for determining a timing advance, TA, after performing a positioning measurement. At block 620, the terminal device 110 obtains, after performing the positioning measurement, a TA value based on the configuration.

In some embodiments, the configuration may indicate a position threshold, and wherein the terminal device may be caused to obtain the TA value by performing one of the following based on determining that a difference associated with a position change of the terminal device is above the position threshold: a random access to acquire the TA value, determining the TA value by adjusting a previous TA value to be a value below a network-configured threshold value, determining a first fraction of a previous TA value as the TA value, wherein the first fraction ranges from zero to one, or determining the TA value based on omitting a number of time advance commands, TACs, last received from the network device.

In some embodiments, the terminal device 110 may be further caused to obtain the TA value by performing the following based on determining that the difference is below the position threshold: determining a second fraction of a previous TA value as the TA value, wherein the second fraction ranges from zero to one.

In some embodiments, the terminal device 110 may be further caused to perform one of the following: continuing running a time alignment timer, TAT, corresponding to a previous TA value, or resetting a TAT corresponding to a previous TA value.

In some embodiments, the terminal device 110 may be further caused to determine the difference associated with the position change based on a first position of the terminal device prior to the positioning measurement and a second position of the terminal device determined from the positioning measurement.

In some embodiments, the difference may comprise at least one of the following: a geometrical difference between the first position and the second position, or a time difference between a first time adjustment value determined based on the first position and a second time adjustment value determined based on the second position.

In some embodiments, the configuration may indicate a validity threshold, and wherein the terminal device 110 may be caused to obtain the TA value by performing one of the following based on determining that a duration for which the terminal device applies satellite assistance information is above the validity threshold: determining the TA value based on keeping a number of or a fraction of time advance commands, TACs, last received from the network device, or a random access to acquire the TA value.

In some embodiments, the terminal device 110 may be caused to obtain the TA value by performing one of the following based on determining that the duration is below the validity threshold: determining the TA value based on omitting a number of or a fraction of time advance commands, TACs, last received from the network device, or a random access to acquire the TA value.

In some embodiments, the terminal device 110 may be caused to determine the duration of the satellite assistance information based on a difference between an epoch time of the satellite assistance information and a current time.

In some embodiments, the configuration may indicate that at least one TAC received from the network device is persistent for determining the TA value after the positioning measurement. In some embodiments, the terminal device 110 may be further caused to: receive a TAC with a flag indicating that the TAC is persistent for determining the TA value.

In some embodiments, the configuration may indicate determining a third fraction of a previous TA value as the TA value, and wherein the third fraction ranges from zero to one. In some embodiments, the configuration may indicate performing a random access to acquire the TA value.

In some embodiments, the terminal device may be caused to receive the configuration by receiving at least one of the following: a trigger command for the positioning measurement, a media access control, MAC, control element, CE, a radio resource control, RRC, configuration, a system information broadcast, an active configuration, an activation of a pre-configured configuration, or a measurement gap configuration for the positioning measurement.

In some embodiments, the positioning measurement may comprise at least one of: a global navigation satellite system, GNSS, measurement, a multi-cell round trip time, RTT, measurement or an observed time difference of arrival, OTDOA, measurement.

Fig. 7 illustrates a flowchart of an example method 700 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 700 will be described from the perspective of the network device 120 with reference to Fig. 1B.

At block 710, the network device 120 transmits, to the terminal device 110, a configuration for determining a timing advance, TA, after performing a positioning measurement. At block 720, the network device 120 receives, from the terminal device 110, a random access channel or a transmission using a TA value obtained based on the configuration.

In some embodiments, the configuration may indicate the terminal device 110 to obtain the TA value by performing one of the following based on determining that a difference associated with a position change of the terminal device is above a position threshold: a random access to acquire the TA value, determining the TA value by adjusting a previous TA value to be a value below a network-configured threshold value, determining a first fraction of a previous TA value as the TA value, wherein the first fraction ranges from zero to one, or determining the TA value based on omitting a number of time advance commands, TACs, last received from the network device.

In some embodiments, the configuration may further indicate the terminal device 110 to obtain the TA value by performing the following based on determining that the difference is below the position threshold: determining a second fraction of a previous TA value as the TA value, wherein the second fraction ranges from zero to one.

In some embodiments, the configuration may further indicate the terminal device 110 to perform one of the following: continuing running a time alignment timer, TAT, corresponding to a previous TA value, or resetting a TAT corresponding to a previous TA value.

In some embodiments, the difference may comprise at least one of the following: a geometrical difference between a first position of the terminal device prior to the positioning measurement and a second position of the terminal device determined from the positioning measurement, or a time difference between a first time adjustment value determined based on the first position and a second time adjustment value determined based on the second position.

In some embodiments, the configuration may indicate the terminal device 110 to obtain the TA value by performing one of the following based on determining that a duration for which the terminal device applies satellite assistance information is above a validity threshold: determining the TA value based on keeping a number of or a fraction of time advance commands, TACs, last received from the network device.

In some embodiments, the configuration may further indicate the terminal device 110 to obtain the TA value by performing one of the following based on determining that the duration is below the validity threshold: determining the TA value based on omitting a number of or a fraction of time advance commands, TACs, last received from the network device, or a random access to acquire the TA value.

In some embodiments, the configuration may further indicate that at least one TAC received from the network device is persistent for determining the TA value after the positioning measurement.

In some embodiments, the network device 120 may be further caused to: transmit, to the terminal device, a TAC with a flag indicating that the TAC is persistent for determining the TA value.

In some embodiments, the configuration may indicate the terminal device 110 to determine a third fraction of a previous TA value as the TA value, and wherein the third fraction ranges from zero to one. In some embodiments, the configuration may indicate the terminal device 110 to perform a random access to acquire the TA value.

In some embodiments, the network device 120 may be caused to transmit the configuration by transmitting at least one of the following: a trigger command for the positioning measurement, a media access control, MAC, control element, CE, a radio resource control, RRC, configuration, a system information broadcast, an active configuration, an activation of a pre-configured configuration, or a measurement gap configuration for the positioning measurement.

In some embodiments, an apparatus capable of performing any of the method 600 (for example, the terminal device 110) may comprise means for performing the respective steps of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises: means for obtaining a configuration for determining a timing advance, TA, after performing a positioning measurement; and means for obtaining, after performing the positioning measurement, a TA value based on the configuration.

In some embodiments, the configuration may indicate a position threshold, and the means for obtaining the TA value may comprise means for performing one of the following based on determining that a difference associated with a position change of the terminal device is above the position threshold: a random access to acquire the TA value, determining the TA value by adjusting a previous TA value to be a value below a network-configured threshold value, determining a first fraction of a previous TA value as the TA value, wherein the first fraction ranges from zero to one, or determining the TA value based on omitting a number of time advance commands, TACs, last received from the network device.

In some embodiments, the means for obtaining the TA value may comprise means for performing the following based on determining that the difference is below the position threshold: determining a second fraction of a previous TA value as the TA value, wherein the second fraction ranges from zero to one.

In some embodiments, the apparatus may further comprise means for performing one of the following: continuing running a time alignment timer, TAT, corresponding to a previous TA value, or resetting a TAT corresponding to a previous TA value.

In some embodiments, the apparatus may further comprise means for determining the difference associated with the position change based on a first position of the terminal device prior to the positioning measurement and a second position of the terminal device determined from the positioning measurement.

In some embodiments, the configuration may indicate a validity threshold, and the means for obtaining the TA value may comprise means for performing one of the following based on determining that a duration for which the terminal device applies satellite assistance information is above the validity threshold: determining the TA value based on keeping a number of or a fraction of time advance commands, TACs, last received from the network device, or a random access to acquire the TA value.

In some embodiments, the means for obtaining the TA value may comprise means for performing one of the following based on determining that the duration is below the validity threshold: determining the TA value based on omitting a number of or a fraction of time advance commands, TACs, last received from the network device, or a random access to acquire the TA value.

In some embodiments, the apparatus may further comprise means for determining the duration of the satellite assistance information based on a difference between an epoch time of the satellite assistance information and a current time.

In some embodiments, the configuration may indicate that at least one TAC received from the network device is persistent for determining the TA value after the positioning measurement. In some embodiments, the apparatus may further comprise means for receiving a TAC with a flag indicating that the TAC is persistent for determining the TA value.

In some embodiments, the means for obtaining the configuration may comprise means for receiving at least one of the following: a trigger command for the positioning measurement, a media access control, MAC, control element, CE, a radio resource control, RRC, configuration, a system information broadcast, an active configuration, an activation of a pre-configured configuration, or a measurement gap configuration for the positioning measurement.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 600. In some embodiments, the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 700 (for example, the network device 120) may comprise means for performing the respective steps of the method 700. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises: means for transmitting, to a terminal device, a configuration for determining a timing advance, TA, after performing a positioning measurement; and means for receiving, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.

In some embodiments, the apparatus may further comprise means for transmitting, to the terminal device, a TAC with a flag indicating that the TAC is persistent for determining the TA value.

In some embodiments, the means for transmitting the configuration may comprise means for transmitting at least one of the following: a trigger command for the positioning measurement, a media access control, MAC, control element, CE, a radio resource control, RRC, configuration, a system information broadcast, an active configuration, an activation of a pre-configured configuration, or a measurement gap configuration for the positioning measurement.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 700. In some embodiments, the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

FIG. 8 is a simplified block diagram of a device 800 that is suitable for implementing embodiments of the present disclosure. The device 800 may be provided to implement the communication device, for example the terminal device 110 and the network device 120 as shown in Fig. 1B. As shown, the device 800 includes one or more processors 810, one or more memories 840 coupled to the processor 810, and one or more communication modules 840 coupled to the processor 810.

The communication module 840 is for bidirectional communications. The communication module 840 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 810 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 800 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 820 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 824, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 822 and other volatile memories that will not last in the power-down duration.

A computer program 830 includes computer executable instructions that are executed by the associated processor 810. The program 830 may be stored in the ROM 824. The processor 810 may perform any suitable actions and processing by loading the program 830 into the RAM 822.

The embodiments of the present disclosure may be implemented by means of the program 830 so that the device 800 may perform any process of the disclosure as discussed with reference to Figs. 2 to 7. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 830 may be tangibly contained in a computer readable medium which may be included in the device 800 (such as in the memory 820) or other storage devices that are accessible by the device 800. The device 800 may load the program 830 from the computer readable medium to the RAM 822 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 9 shows an example of the computer readable medium 900 in form of CD or DVD. The computer readable medium has the program 830 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the method 600 or 700 as described above with reference to Figs. 2-7. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM) .

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A terminal device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to:

obtain a configuration for determining a timing advance, TA, after performing a positioning measurement; and

obtain, after performing the positioning measurement, a TA value based on the configuration.
The terminal device of claim 1, wherein the configuration indicates a position threshold, and wherein the terminal device is caused to obtain the TA value by performing one of the following based on determining that a difference associated with a position change of the terminal device is above the position threshold:

a random access to acquire the TA value,

determining the TA value by adjusting a previous TA value to be a value below a network-configured threshold value,

determining a first fraction of a previous TA value as the TA value, wherein the first fraction ranges from zero to one, or

determining the TA value based on omitting a number of time advance commands, TACs, last received from the network device.
The terminal device of claim 2, wherein the terminal device is further caused to obtain the TA value by performing the following based on determining that the difference is below the position threshold:

determining a second fraction of a previous TA value as the TA value, wherein the second fraction ranges from zero to one.
The terminal device of claim 2 or 3, wherein the terminal device is further caused to perform one of the following:

continuing running a time alignment timer, TAT, corresponding to a previous TA value, or

resetting a TAT corresponding to a previous TA value.
The terminal device of any of claims 2 to 4, wherein the terminal device is further caused to:

determine the difference associated with the position change based on a first position of the terminal device prior to the positioning measurement and a second position of the terminal device determined from the positioning measurement.
The terminal device of claim 5, wherein the difference comprises at least one of the following:

a geometrical difference between the first position and the second position, or

a time difference between a first time adjustment value determined based on the first position and a second time adjustment value determined based on the second position.
The terminal device of any of claims 1 to 6, wherein the configuration indicates a validity threshold, and wherein the terminal device is caused to obtain the TA value by performing one of the following based on determining that a duration for which the terminal device applies satellite assistance information is above the validity threshold:

determining the TA value based on keeping a number of or a fraction of time advance commands, TACs, last received from the network device, or

a random access to acquire the TA value.
The terminal device of claim 7, wherein the terminal device is further caused to obtain the TA value by performing one of the following based on determining that the duration is below the validity threshold:

determining the TA value based on omitting a number of or a fraction of time advance commands, TACs, last received from the network device, or

a random access to acquire the TA value.
The terminal device of claim 7 or 8, wherein the terminal device is further caused to:

determine the duration of the satellite assistance information based on a difference between an epoch time of the satellite assistance information and a current time.
The terminal device of any of claims 1 to 9, wherein the configuration indicates that at least one TAC received from the network device is persistent for determining the TA value after the positioning measurement.
The terminal device of claim 10, wherein the terminal device is further caused to:

receive a TAC with a flag indicating that the TAC is persistent for determining the TA value.
The terminal device of any of claims 1 to 11, wherein the configuration indicates determining a third fraction of a previous TA value as the TA value, and wherein the third fraction ranges from zero to one.
The terminal device of claim 1, wherein the configuration indicates performing a random access to acquire the TA value.
The terminal device of any of claims 1 to 13, wherein the terminal device is caused to obtain the configuration by receiving at least one of the following:

a trigger command for the positioning measurement,

a media access control, MAC, control element, CE,

a radio resource control, RRC, configuration,

a system information broadcast,

an active configuration,

an activation of a pre-configured configuration, or

a measurement gap configuration for the positioning measurement.
The terminal device of any of claims 1 to 14, wherein the positioning measurement comprises at least one of:

a global navigation satellite system, GNSS, measurement,

a multi-cell round trip time, RTT, measurement or

an observed time difference of arrival, OTDOA, measurement.
A network device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to:

transmit, to a terminal device, a configuration for determining a timing advance, TA, after performing a positioning measurement; and

receive, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.
The network device of claim 16, wherein the configuration indicates the terminal device to obtain the TA value by performing one of the following based on determining that a difference associated with a position change of the terminal device is above a position threshold:

a random access to acquire the TA value,

determining the TA value by adjusting a previous TA value to be a value below a network-configured threshold value,

determining a first fraction of a previous TA value as the TA value, wherein the first fraction ranges from zero to one, or

determining the TA value based on omitting a number of time advance commands, TACs, last received from the network device.
The network device of claim 17, wherein the configuration further indicates the terminal device to obtain the TA value by performing the following based on determining that the difference is below the position threshold:

determining a second fraction of a previous TA value as the TA value, wherein the second fraction ranges from zero to one.
The network device of claim 17 or 18, wherein the configuration further indicates the terminal device to perform one of the following:

continuing running a time alignment timer, TAT, corresponding to a previous TA value, or

resetting a TAT corresponding to a previous TA value.
The network device of any of claims 17 to 19, wherein the difference comprises at least one of the following:

a geometrical difference between a first position of the terminal device prior to the positioning measurement and a second position of the terminal device determined from the positioning measurement, or

a time difference between a first time adjustment value determined based on the first position and a second time adjustment value determined based on the second position.
The network device of any of claims 16 to 20, wherein the configuration indicates the terminal device to obtain the TA value by performing one of the following based on determining that a duration for which the terminal device applies satellite assistance information is above a validity threshold:

determining the TA value based on keeping a number of or a fraction of time advance commands, TACs, last received from the network device.
The network device of claim 21, wherein the configuration further indicates the terminal device to obtain the TA value by performing one of the following based on determining that the duration is below the validity threshold:

determining the TA value based on omitting a number of or a fraction of time advance commands, TACs, last received from the network device, or

a random access to acquire the TA value.
The network device of any of claims 16 to 22, wherein the configuration indicates that at least one TAC received from the network device is persistent for determining the TA value after the positioning measurement.
The network device of claim 23, wherein the network device is further caused to:

transmit, to the terminal device, a TAC with a flag indicating that the TAC is persistent for determining the TA value.
The network device of any of claims 16 to 24, wherein the configuration indicates the terminal device to determine a third fraction of a previous TA value as the TA value, and wherein the third fraction ranges from zero to one.
The network device of claim 16, wherein the configuration indicates the terminal device to perform a random access to acquire the TA value.
The network device of any of claims 16 to 26, wherein the network device is caused to transmit the configuration by transmitting at least one of the following:

a trigger command for the positioning measurement,

a media access control, MAC, control element, CE,

a radio resource control, RRC, configuration,

a system information broadcast,

an active configuration,

an activation of a pre-configured configuration, or

a measurement gap configuration for the positioning measurement.
The network device of any of claims 16 to 27, wherein the positioning measurement comprises at least one of:

a global navigation satellite system, GNSS, measurement,

a multi-cell round trip time, RTT, measurement or

an observed time difference of arrival, OTDOA, measurement.
A method comprising:

obtaining, at a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and

obtaining, after performing the positioning measurement, a TA value based on the configuration.
A method comprising:

transmitting, at a network device and to a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and

receiving, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.
An apparatus, comprising:

means for obtaining, at a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and

means for obtaining, after performing the positioning measurement, a TA value based on the configuration.
An apparatus, comprising:

means for transmitting, at a network device and to a terminal device, a configuration for determining a timing advance, TA, after a positioning measurement; and

means for receiving, from the terminal device, a random access channel or a transmission using a TA value obtained based on the configuration.
A computer readable medium comprising program instructions for causing an apparatus to perform at least the method of any of claims 29 to 30.