Patent Description:
To this end, the present disclosure presents a network entity for determining time information and providing the time information to another network entity. This disclosure also presents a network entity that synchronizes an internal time valid at the network entity with an external time valid at an external network entity. Further, the present disclosure presents corresponding methods.

Precise time reference synchronization within multiple clock domains and deterministic data transmission over the <NUM> system (5GS) is desired by the applications in diverse vertical industries, such as smart factory, Program Making & Special Events (PMSE), autonomous driving and its underlying V2X communication, etc..

<FIG> schematically illustrates, in a smart factory scenario, working clock domain interactions including "Merge" <NUM> and "Separate" <NUM>, according to the prior art. The interactions between the working clock domain are exemplarily discussed in <NPL>.

In conventional mobile communication systems, the synchronization is normally done by simple broadcasting of time information and there is no strict control of communication delay. As a result, the time synchronization bias and data transfer jitter becomes uncontrollable, which cannot meet the aforementioned requirements from diverse vertical industries.

<CIT> discloses one or more relay stations being employed along a wireless communication access path between an ingress station and an egress station.

<NPL>, discloses time sensitive networking related enhancements based on accurate reference timing.

<NPL>, discloses challenges to be considered in rolling out mobile backhaul synchronization solutions. <CIT> discloses an electronic time or timer system comprising a counter-based time generator for continuously generating raw base time, and a translator for translating between raw base time and local precise time.

In view of the above-mentioned problems and disadvantages, embodiments of the present invention aim to improve the conventional devices and methods. Embodiments of the present invention have thereby the objective to provide network entities for a wireless network system (e.g., in a core network) and methods performed by the network entities. In some embodiments of the invention, the delay measurement and the jitter control may be provided, for example, in the cellular communication system.

An objective is achieved by the solution provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims. In the following, parts of the description and drawings referring to embodiments not covered by the claims, are not part of the invention, but are illustrative examples necessary for understanding the invention.

Moreover, a further objective of embodiments of the present invention is to support multiple clock domains for a <NUM> System functioning as a time-aware relay and to achieve time-sensitive deterministic transmission with fixed delay/low jitter.

This may be achieved by an End-to-End (E2E) synchronization within the 5GS. The two ends of the 5GS may be for instance a User Plane Function (UPF) and a User Equipment (UE), or two UEs. Efficient delivery of ingress/egress timestamps may be used for measuring residence time (delay within 5GS) and/or for realizing adaptive buffering until fixed residence time before egress.

A first aspect of the disclosure provides a network entity for a wireless network system, wherein the network entity is configured to obtain an ingress time of a received packet, the ingress time indicating the time at which the packet enters the network system, determine time information regarding the packet based on the ingress time, determine if the packet belongs to a set of packets that enter the network system periodically, determine an interval, if the packet belongs to such a set of packets, provide the time information to another network entity, and provide information indicative of the periodicity to the other network entity, wherein the information indicative of the periodicity is based on the interval.

The network entity may be, for example, a network node, such as a User equipment (UE), or a User Plane Function (UPF). The UPF may also be a network node or it may be implemented as a function in a network node. The wireless network system may be a Long Term Evolution (LTE) network system, a fifth Generation (<NUM>) network system, etc. In some embodiments, the network entity may be in the core network, for example, the wireless network system may be the <NUM> network system and the network entity may be the UPF being in the core network of the <NUM> network system.

The network entity (e.g., the UE or the UPF) is configured to obtain the ingress time of a received packet. The received packet may be received from an entity or a node in an external network. The network entity (e.g., the UE or the UPF) may further determine the time information and provide the time information to another network entity which may be, for example, another UE or another UPF (e.g., being in the core network of the wireless network system).

In an implementation form of the first aspect, the time information includes the ingress time of the packet.

In a further implementation form of the first aspect, the network entity is further configured to calculate an egress time of the packet, the egress time indicating the time at which the packet leaves the network system, based on the ingress time and a predetermined residence time of the packet in the network system, wherein the time information includes the egress time.

In a further implementation form of the first aspect, the network entity is further configured to obtain a synchronization message associated with the packet, modify the synchronization message, in particular modify a correction field of the synchronization message, according to the predetermined residence time, and provide the modified synchronization message to the other network entity.

In an implementation, the time interval is indicative of the periodicity of the set of packets. Based on the knowledge of the time interval, the network entity can determine the egress time. As an example, the network entity determine the egress time of packets in the set of packets based on the egress time of a first packet of the set of packets and on the time interval. In particular, the network entity may add to the egress time of a packet the time interval to obtain the egress time of the next packet.

In a further implementation form of the first aspect, the network entity is further configured to incorporate the time information into a timestamp bit-format, and truncate the timestamp bit-format by removing at least one most significant bit and/or at least one least significant bit.

In a further implementation form of the first aspect, the network entity is further configured to provide the time information to the other network entity by at least one of:.

Moreover, in some embodiments, a first part of the time information (i.e. the time information after the truncation) may be carried in the data plane and second part of the time information (i.e. the truncated part of the time information) may be carried in the control plane.

A second aspect of the disclosure provides a wireless network system comprising the network entity according to the first aspect or any of its implementation forms and another network entity, wherein the other network entity is configured to obtain time information regarding a received packet from the network entity, obtain information indicative of a periodicity of a set of packets that enter the network system periodically, wherein the packet belongs to the set of packets, and obtain an egress time of the packet, the egress time indicating a time at which the packet leaves the network system, based on the time information and the periodicity.

The other network entity (i.e., of the second aspect) may be, for example, a UE or a UPF. The other network entity is configured to obtain time information regarding the received packet from the network entity which is an entity within the network system, for example from another UE or UPF.

In a further implementation form of the second aspect, the other network entity is further configured to determine a residence time of the packet in the network system based on the ingress time and the egress time of the packet, wherein the time information includes an ingress time of the packet, the ingress time indicating a time at which the packet enters the wireless network system.

In a further implementation form of the second aspect, the other network entity is further configured to determine the egress time of the packet based on the ingress time and a predetermined residence time of the packet in the network system, wherein the time information includes an ingress time of the packet, the ingress time indicating a time at which the packet enters the wireless network system.

In a further implementation form of the second aspect, the time information includes the egress time, and the other network entity is configured to extract the egress time from the time information.

In a further implementation form of the second aspect, the other network entity is further configured to obtain a predetermined residence time of the packet in the network system.

In a further implementation form of the second aspect, the other network entity is further configured to provide a synchronization message including information indicative of the residence time of the packet in the network system to an external network entity, wherein the external network entity is external to the wireless network system.

In a further implementation form of the second aspect, the other network entity is further configured to generate the synchronization message by modifying a synchronization message received from the network entity, in particular modifying a correction field of the synchronization message, according to the residence time.

In a further implementation form of the second aspect, the other network entity is further configured to buffer the packet until the egress time is reached, and provide the packet to an external network entity at the egress time, wherein the external network entity is external to the wireless network system.

In a further implementation form of the second aspect, the other network entity is further configured to synchronize a time with the network entity.

For example, the other network entity (e.g., the UE or the UPF) may synchronize the time with the internal network entities. In some embodiments, there is no need for the UE or UPF to do synchronization with the external network entities.

In a further implementation form of the first aspect, the network entity is further configured to synchronize an internal time valid at the network entity with an external time valid at an external network entity, wherein the external network entity is external to the wireless network system, provide time information to another network entity, wherein the time information includes a mapping of the internal time to the external time.

The network entity (e.g., of the first aspect) may be a UE or a UPF. Moreover, the time information may be provided to another network entity which may be an entity in the network system, for example, another UE or another UPF.

In an implementation form of the first aspect, the time information further includes a domain number, indicating a clock domain of the external time.

For example, the clock domain may include different working clock domains and the global clock domain.

A fifth aspect of the disclosure provides a method performed by a network entity for a wireless network system, wherein the method comprises obtaining an ingress time of a received packet, the ingress time indicating the time at which the packet enters the network system, determining time information regarding the packet based on the ingress time, determining if the packet belongs to a set of packets that enter the network system periodically, determining an interval, if the packet belongs to such a set of packets, providing the time information to another network entity, and providing information indicative of the periodicity to the other network entity, wherein the information indicative of the periodicity is based on the interval.

In an implementation form of the fifth aspect, the time information includes the ingress time of the packet.

In a further implementation form of the fifth aspect, the method further comprises calculating an egress time of the packet, the egress time indicating the time at which the packet leaves the network system, based on the ingress time and a predetermined residence time of the packet in the network system, wherein the time information includes the egress time.

In a further implementation form of the fifth aspect, the method further comprises obtaining a synchronization message associated with the packet, modifying the synchronization message, in particular modifying a correction field of the synchronization message, according to the predetermined residence time, and providing the modified synchronization message to the other network entity.

In a further implementation form of the fifth aspect, the method further comprises incorporating the time information into a timestamp bit-format, and truncating the timestamp bit-format by removing at least one most significant bit and/or at least one least significant bit.

In a further implementation form of the fifth aspect, the method further comprises providing the time information to the other network entity by at least one of:.

A sixth aspect of the disclosure provides a method performed by a wireless network system comprising a network entity and another network entity, wherein the method comprises the method of the fifth aspect or any of its implementation forms performed by the network entity, wherein the method further comprises the other network entity performing: obtaining time information regarding a received packet from another network entity, obtaining information indicative of a periodicity of a set of packets that enter the network system periodically, wherein the packet belongs to the set of packets; and obtaining an egress time of the packet, the egress time indicating a time at which the packet leaves the network system, based on the time information and the periodicity.

In an implementation form of the sixth aspect, the time information includes an ingress time of the packet, the ingress time indicating a time at which the packet enters the network system, and the method further comprises determining the egress time based on the ingress time.

In a further implementation form of the sixth aspect, the method further comprises determining a residence time of the packet in the network system based on the ingress time and the egress time of the packet.

In a further implementation form of the sixth aspect, the method further comprises determining the egress time of the packet based on the ingress time and a predetermined residence time of the packet in the network system.

In a further implementation form of the sixth aspect, the time information includes the egress time, and the method further comprises extracting the egress time from the time information.

In a further implementation form of the sixth aspect, the method further comprises obtaining a predetermined residence time of the packet in the network system.

In a further implementation form of the sixth aspect, the method further comprises providing a synchronization message including information indicative of the residence time of the packet in the network system to an external network entity.

In a further implementation form of the sixth aspect, the method further comprises generating the synchronization message by modifying a synchronization message received from the network entity, in particular modifying a correction field of the synchronization message, according to the residence time.

In a further implementation form of the sixth aspect, the method further comprises buffering the packet until the egress time is reached, and provide the packet to an external network entity at the egress time.

In a further implementation form of the sixth aspect, the method further comprises synchronizing a time with the network entity, wherein the network entity is within the wireless network system.

A ninth aspect of the disclosure provides a computer program product comprising a program code for controlling a network entity according to the first aspect, or for carrying out, when implemented on a processor, a method according to the fifth aspect.

The above described aspects and implementation forms of the present disclosure will be explained in the following description of specific embodiments in relation to the enclosed drawings, in which:.

The following embodiment is not encompassed by the wording of the claims but is considered as useful for understanding the invention.

<FIG> schematically illustrates a network entity <NUM> for a wireless network system <NUM>, for determining time information <NUM>, according to embodiments of the invention.

The network entity <NUM> and/or the network entity <NUM> may be the UE or the UPF and the wireless network system <NUM> may be the <NUM> network system. For example, the network entity <NUM> may be the UPF being in the core network of the <NUM> network system and the other network entity <NUM> may be the UE (or the UPF) in the <NUM> network system.

The network entity <NUM> (e.g., the UE or the UPF) is configured to obtain an ingress time t<NUM> of a received packet <NUM>, the ingress time t<NUM> indicating the time at which the packet <NUM> enters the network system <NUM>.

The network entity <NUM> is further configured to determine time information <NUM> regarding the packet <NUM> based on the ingress time t<NUM> , and provide the time information <NUM> to another network entity <NUM>.

<FIG> also illustrates a network entity <NUM> for a wireless network system <NUM>, wherein the network entity <NUM> is configured to obtain time information <NUM> regarding a received packet <NUM> from another network entity <NUM>, and obtain an egress time t<NUM> of the packet <NUM>, the egress time t<NUM> indicating a time at which the packet <NUM> leaves the network system <NUM>, based on the time information <NUM>.

For example, in some embodiments, a new type of UE or UPF may be provided which may record the ingress timestamp and may further signal the timestamp to another UE or another UPF at the other end. The timestamp is in this case an example of time information <NUM>. Moreover, it may further egress a packet according to a specified egress time, correct the correction field using measured delay between ingress and egress times, etc..

Moreover, the signalling for the timestamps, or in general for the time information, between ingress and egress points may be based on, for example:.

In some embodiments, the measurement of the E2E delay within 5GS (residence time) and correction in synchronization message may be provided, for example:.

In some embodiments, the adaptive buffering may be provided until the fixed E2E delay within the 5GS (residence time), for example:.

In some embodiments, the formats for representing timestamps may be provided in order to reduce the overheads, for example, it may be based on:.

<FIG> schematically illustrates a network entity <NUM> for a wireless network system <NUM> for synchronizing an internal time ts with an external time Ek(ts ), according to various embodiments of the invention.

The network entity <NUM> is configured to synchronize an internal time ts valid at the network entity <NUM> with an external time Ek(ts ) valid at an external network entity <NUM>.

The network entity <NUM> is further configured to provide time information <NUM> to another network entity <NUM>, wherein the time information <NUM> includes a mapping of the internal time ts to the external time Ek(ts ).

<FIG> also illustrates a network entity <NUM> for a network system <NUM>, wherein the network entity <NUM> is configured to obtain time information <NUM> from another network entity <NUM>, wherein the time information <NUM> includes a mapping of an internal time ts valid at the other network entity <NUM> and an external time Ek(ts ) valid at a first external network entity <NUM>, and synchronize an internal time ts valid at the network entity <NUM> with an external time Ek(ts ) valid at a second external network entity <NUM>, based on the mapping in the time information <NUM>.

The network entity <NUM> and the network entity <NUM> may be the same network entity or may be based on the same type of network entities. For example, both network entities <NUM> and <NUM> may be the UE or the UPF. Similarly, the network entity <NUM> and the network entity <NUM> may be the same network entity or may be based on the same type of network entities. For example, both network entities <NUM> and <NUM> may be the other UE or the other UPF, without limiting the present disclosure to a specific configuration in that regard.

Furthermore, the time information <NUM> may include the mapping of the internal time ts valid at the other network entity <NUM> and the external time Ek(ts ) valid at the first external network entity <NUM>. The mapping may be, for example, comparing the internal time ts to the external time Ek(t), wherein k is the clock domain number and measuring the frequency offset Δk between the internal time (i.e., the internal clock) and the external time (i.e., the external clock).

<FIG> illustrates an exemplarily scheme of timing in a wireless communication system <NUM>, which can be carried out by the embodiments of the invention, including the wireless communication system <NUM> described in <FIG> and <FIG>.

For example, the ingress time of user data is variable. Moreover, the Tx/Rx processing time periods are implementation specific and may also be variable.

Furthermore, the wireless transmission time start at the beginning of a specific slot or a symbol (mini-slot). Hence, the Tx holding time can be obtained, for example, by the network entity <NUM> by achieving the pre-determined fixed delay and/or measuring the variable delay.

For example, for supporting multiple clock domains with a time-aware relay, the exact residence time of a packet staying in the 5GS may be measured and added in "correctionField" of TSN Sync and Follow_Up messages. The measured delay in real-time can then be provided to the TSN's synchronization protocol for optimizing its accuracy.

<FIG> illustrates an exemplary scheme of an architectural view. The scheme of the architectural view in <FIG> is illustrated, as an example, for the wireless network system <NUM> being the <NUM> network system comprising one or more network entities. The network entities may be or may include the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>. Without limiting the present disclosure, in following, the scheme of the architectural view is discussed based on the UPF <NUM> (i.e., the network entity <NUM>) in the core network and the UE <NUM> being the other network entity (other network entity).

Moreover, the network entity <NUM> (and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>) may further synchronize the internal time with the external time of the external network entity <NUM> which is the TSN of the <NUM> network system.

The architectural view comprises the core network (exemplary illustrated with 5GS as Logic Bridge or link) performing an internal E2E synchronization between the UE <NUM> and the UPF <NUM> as well as between the UEs <NUM> and <NUM> (over Uu or sidelink). In addition, with the 5GS internal sync, it may be possible to achieve the delay measurement between any pair of N60 or N6 interfaces.

<FIG> schematically illustrates a procedure <NUM> for a live measurement and correction of residence time based on signaling the ingress time. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

In the following, the procedure <NUM> is exemplarily discussed to be partially performed by the network entity <NUM> (e.g., the UE or the UPF) being located at the ingress point and the network entity <NUM> (e.g., the UE or the UPF) being located at the egress point of the wireless network system <NUM>.

In the procedure <NUM>, the network entity <NUM> (e.g., the UE or the UPF) obtains the synchronization message from the upstream node <NUM>. The network entity <NUM> further obtains the ingress time t<NUM> and sends a signaling including the t<NUM> to another network entity <NUM> (another UE or another UPF).

Moreover, the another network entity <NUM> (another UE or another UPF) may determine the egress time t<NUM> , add the "correctionField" with the residence time TR = t<NUM> -t<NUM>. Furthermore, the another network entity <NUM> may further wait until the time t<NUM> , and at the time of t<NUM> send the synchronization message with correction to downstream node <NUM>.

The procedure <NUM> for the live measurement and correction of residence time based on the signaling the ingress time may be applicable to variable delays in 5GS. The procedure <NUM> may be used in applications with bounded delay requirements. Further, the procedure <NUM> does not require changes to the <NUM> Quality of Service (QoS) framework.

<FIG> schematically illustrates a procedure <NUM> for a live measurement and correction of residence time based on signaling the targeted egress time. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

In the following, the procedure <NUM> is exemplarily discussed to be partially performed by the network entity <NUM> (e.g., the UE or the UPF) located at the ingress point and the network entity <NUM> (e.g., the UE or the UPF) located at the egress point of the wireless network system <NUM>.

In the procedure <NUM>, the network entity <NUM> (e.g., the UE or the UPF) obtains the synchronization message from the upstream node <NUM>. The network entity <NUM> further obtains the ingress time t<NUM>. The network entity <NUM> may further determine the targeted egress time t<NUM> and add the "correctionField" with the residence time t<NUM> = t<NUM> + TR. The network entity <NUM> may further send a signaling including the t<NUM> to another network entity <NUM> (another UE or another UPF).

The another network entity <NUM> may wait until the time t<NUM>, and at the time of t<NUM> send the synchronization message with correction to downstream node <NUM>.

The procedure <NUM> for the live measurement and correction of residence time based on the signaling the targeted egress time may be applicable to fixed delays in 5GS. The procedure <NUM> may be used in applications with fixed delay/bounded jitter requirements.

In some embodiments, an adaptive buffering may be provided, for example, until a fixed residence time.

<FIG> schematically illustrates a procedure <NUM> for adaptive buffering based on signaling the ingress time. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

Moreover, <FIG> schematically illustrates a procedure <NUM> for adaptive buffering based on signaling the targeted egress time. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

The adaptive buffering at the egress node may ensure that a precise residence time in the 5GS is maintained.

Moreover, the buffering time may be determined based on either:.

Furthermore, the adaptive buffering may rely on 5GS internal synchronization in the user-plane, for example:.

In the procedure <NUM> of <FIG>, the traffic with random arriving time based on signaling the ingress time, the network entity <NUM> (e.g., the UE or the UPF) obtains the data packet from the upstream node <NUM>. The network entity <NUM> further obtains the ingress time t<NUM> and sends a signaling including the t<NUM> to another network entity <NUM> (another UE or another UPF). Moreover, the another network entity <NUM> (another UE or another UPF) may determine the egress time t<NUM> = t<NUM> + TR and wait until the time t<NUM>. At the egress time t<NUM>, the another network entity <NUM> may send the data packet to downstream node <NUM>.

In the procedure <NUM> of <FIG>, the traffic with random arriving time based on signaling the targeted egress time, the network entity <NUM> (e.g., the UE or the UPF) obtains the data packet from the upstream node <NUM>. The network entity <NUM> obtains the ingress time t<NUM> and may determine the targeted egress time t<NUM> = t<NUM> + TR. Moreover, the network entity <NUM> sends a signaling including the t<NUM> to another network entity <NUM> (another UE or another UPF). The another network entity <NUM> (another UE <NUM> or another UPF <NUM>) may wait until the time t<NUM>. At the egress time t<NUM>, the another network entity <NUM> sends the data packet to downstream node <NUM>.

In some embodiments, a fixed residence time may be achieved.

<FIG> schematically illustrates a procedure <NUM> for achieving fixed residence time for periodic or predictable traffic pattern based on signaling of ingress timestamp. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

In the procedure <NUM>, the fixed residence time for periodic or predictable traffic pattern may be achieved based on signaling of ingress timestamp, for example, by:.

Moreover, <FIG> schematically illustrates a procedure <NUM> for achieving fixed residence time for periodic or predictable traffic pattern based on signaling of egress timestamp. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

In the procedure <NUM>, the fixed residence time for periodic or predictable traffic pattern may be achieved based on signaling of egress timestamp, for example, by:.

In some embodiments, a timestamp compression may be provided. <FIG> schematically illustrates a synchronization message format including high amount of data in IEEE <NUM> timestamp. The compression may be performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

The high amount of data in existing timestamp scheme may be compressed (e.g., by the network entity <NUM>), as it is illustrated in <FIG>, for example:.

Moreover, since the residence time is normally small (< <NUM>), the timestamp data may further be truncated for saving the overhead, for example, by:.

<FIG> schematically illustrates truncation of timestamp for saving overhead. The truncation of the timestamp may performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard. For example, by assuming the original timestamp of <NUM> octets (80bit) with precision of 1ns, by truncating bits #<NUM>~<NUM> and #<NUM>~<NUM> (preserving bits #<NUM>~#<NUM>), the maximum residence time of <NUM> with precision of 128ns may be handled. Moreover, the PCF may be based on (<NUM>) the maximum residence time (delay) and (<NUM>) precision requirement to specify the truncation of the most/least significant digits.

In some embodiments, the signaling methods for timestamps between the ingress and the egress points may be provided. <FIG> schematically illustrates signaling methods for timestamps between ingress point (for example, it may be performed by the network entity <NUM> or the network entity <NUM> located at the ingress point) and egress points (for example, it may be performed by the network entity <NUM> or the network entity <NUM> located at the egress point).

The ingress times and/or the egress times and/or the residence times may be signaled in various ways between the ingress and egress points, for example:.

<FIG> schematically illustrates using reserved data field to deliver the ingress/egress time stamp. In <FIG>, the reserved data field are used to deliver the ingress time stamp (for example, it may be performed by the network entity <NUM> or the network entity <NUM> located at the ingress point) and the egress time stamp (for example, it may be performed by the network entity <NUM> or the network entity <NUM> located at the egress point). Moreover, the reserved field of <NUM> bits in PTP header may be sufficient to accommodate timestamp with nanosecond precision and hundred millisecond of range.

In some embodiments, the reference architecture and signaling within <NUM> system may be provided. <FIG> schematically illustrates a reference architecture in 5GS. In <FIG>, the wireless network system <NUM> is exemplarily discussed to be the <NUM> network system. Moreover, the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> may be the UE or the UPF in the <NUM> network system.

The reference architecture to configure the network for high accuracy time synchronization may be provided, for example, based on:.

Moreover, the reference architecture to communicate the time assistance info over CP, may also be provided, for example, based on:.

<FIG> illustrates an exemplary scheme of communicating the static time assistance information using the CP signaling. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

In the following, the procedure <NUM> is exemplarily discussed to be partially performed by the network entity <NUM> (e.g., the UPF) located at the ingress point and the network entity <NUM> (e.g., the UPF) located at the egress point of the wireless network system <NUM>.

Examples of communicating the static time assistance information using the CP signaling, may be as follows:.

Note that the steps <NUM> to <NUM> may be trigged by the SMF <NUM> using the N2 session modification procedure in order to update the static time assistance info whenever necessary. Moreover, the steps <NUM> to <NUM> may also be used from the SMF <NUM> in order to configure the UPF on the time related treatment.

<FIG> illustrates an exemplary scheme <NUM> of boundary clock based propagation of synchronization without transparent delivery of message. The procedure <NUM> may be (for example, fully or partially) performed by the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM> and/or the network entity <NUM>, without limiting the present disclosure to a specific network entity in that regard.

In the following, the procedure <NUM> is exemplarily discussed to be partially performed by the network entity <NUM> (e.g., the UE or the UPF) performing the slave function and the network entity <NUM> (e.g., the UE or the UPF) performing the master function.

In some embodiments, the transmission of a timestamp within 5GS may not be triggered by an external sync message but triggered autonomously by the Slave Function <NUM> within the 5GS. In some embodiments, not only the internal timestamp ts but also its according external time Ek(ts ), the domain number k, and, optionally, the external to internal frequency offset Δk may be transferred to the Master Function <NUM> in one or more message(s) {ts , Ek(ts ), Δk, k}.

<FIG> shows a method <NUM> according to an embodiment of the invention for a network entity <NUM> for a wireless network system <NUM>. The method <NUM> may be carried out by the device <NUM>, as it is described above.

The method <NUM> comprises a step <NUM> of obtaining an ingress time t<NUM> of a received packet <NUM>, the ingress time t<NUM> indicating the time at which the packet <NUM> enters the network system <NUM>.

The method <NUM> further comprises a step <NUM> of determining time information <NUM> regarding the packet <NUM> based on the ingress time t<NUM>.

The method <NUM> further comprises a step <NUM> of providing the time information <NUM> to another network entity <NUM>.

The method <NUM> comprises a step <NUM> of obtaining time information <NUM> regarding a received packet <NUM> from another network entity <NUM>.

The method <NUM> further comprises a step <NUM> of obtaining an egress time t<NUM> of the packet <NUM>, the egress time t<NUM> indicating a time at which the packet <NUM> leaves the network system <NUM>, based on the time information <NUM>.

<FIG> shows a method <NUM> according to an embodiment of the invention for a network entity for a wireless network system <NUM>. The method <NUM> may be carried out by the device <NUM>, as it is described above.

The method <NUM> comprises a step <NUM> of synchronizing an internal time ts valid at the network entity <NUM> with an external time Ek(ts ) valid at an external network entity <NUM>.

The method <NUM> further comprises a step <NUM> of providing time information <NUM> to another network entity <NUM>, wherein the time information <NUM> includes a mapping of the internal time ts to the external time Ek(ts ).

The method <NUM> comprises a step <NUM> of obtaining time information <NUM> from another network entity <NUM>, wherein the time information <NUM> includes a mapping of an internal time ts valid at the other network entity <NUM> and an external time Ek(ts ) valid at a first external network entity <NUM>.

The method <NUM> further comprises a step <NUM> of synchronizing an internal time ts valid at the network entity <NUM> with an external time Ek(ts ) valid at a second external network entity <NUM>, based on the mapping in the time information <NUM>.

The mapping may be, for example, comparing the internal time ts to the external time Ek(t), wherein k is the clock domain number and measuring the frequency offset Δk between the internal time (i.e., the internal clock) and the external time (i.e., the external clock).

Claim 1:
A network entity (<NUM>) for a wireless network system (<NUM>), wherein the network entity (<NUM>) is configured to:
obtain an ingress time (t<NUM> ) of a received packet (<NUM>), the ingress time (t<NUM> ) indicating the time at which the packet (<NUM>) enters the wireless network system (<NUM>);
determine time information (<NUM>) regarding the packet (<NUM>) based on the ingress time (t<NUM> );
determine if the packet (<NUM>) belongs to a set of packets that enter the network system (<NUM>) periodically;
determine an interval, if the packet (<NUM>) belongs to such a set of packets;
provide the time information (<NUM>) to another network entity (<NUM>); and
provide information indicative of the periodicity to the other network entity (<NUM>), wherein the information indicative of the periodicity is based on the interval.