TIME INFORMATION IN A SPLIT ARCHITECTURE

TECHNICAL FIELD

The present disclosure relates, in general, to wireless communications and, more particularly, apparatus and methods for network pre-compensation of reference time information in a split architecture.

BACKGROUND

In 3 ^rd Generation Partnership Project (3GPP) Release 16, 3GPP Technical Specification Group Service and System Aspects WG2 (TSG SA2) and Radio Layer 2 (RAN2) have aimed at providing support for Time Sensitive Networking (TSN) such that the 5 ^th Generation System (5GS) can operate as a TSN logical bridge between TSN-based network elements. Successful 5 ^th Generation (5G)-TSN integration to support time critical industrial application requires end-to- end time synchronization. Time reference information such as, for example, that which may be associated with a TSN Grandmaster Clock, is needed for the applications running on end devices in most of the industrial automation deployments. The same or an additional type of time reference information is also required in the bridges of a TSN network (e.g., to realize an ingress to egress traffic delay target for a TSN bridge) when time-based TSN tools are used, like Scheduled Traffic (802.1Qbv), to provide deterministic low latency for time-critical traffic.

Time synchronization requirements from vertical industries has been defined by 3GPP specifications. Table 1 below corresponds to Table 5.6.2-1 from 3GPP TS 22.104 v. 18.2.0 and shows a diverse set of clock synchronization service performance requirements for 5GS.

Table 1: Clock synchronization service performance requirements for 5GS For the integration with TSN, the 5GS is considered as a virtual bridge. For time synchronization support, such a 5G virtual bridge is modelled as a time-aware system as per IEEE 802. IAS. There are two synchronization processes running in parallel in an integrated 5G-TSN system: a 5 ^th Generation (5G) system internal synchronization process (i.e. , distribution of a 5G internal clock required to realize ingress to egress traffic delay targets for a 5GS) and a TSN synchronization process (i.e., needed to realize synchronization between a TSN Grandmaster clock source and devices reachable through the 5GS).

The two synchronization processes can be considered independent from each other. The gNodeB (gNB) only needs to be aware of and synchronized to the 5G reference clock as this is sufficient for the 5GS internal synchronization process to be kept intact, functioning, and independent of the TSN synchronization process such as, for example, the external generalized Precision Time Protocol (gPTP) synchronization process that makes use of gPTP Grand Master clocks delivered transparently through the 5GS.

5GS Internal Synchronization

The use of time synchronization has been common practice already for cellular networks of different generations and is an integral part of operating 5G cellular radio systems. The 5G radio network components themselves are also time synchronized, e.g., for advanced radio transmission, such as synchronized Time Division Duplex (TDD) operation, cooperative multipoint (CoMP) transmission, or carrier aggregation. The new 5G capability introduced when integrating 5G systems and TSN networks is to provide 5G internal clock (reference time) delivery as a service over the 5GS.

• Once the 5G reference time is acquired by a gNB (e.g. from a Global Positioning System (GPS) receiver) it is sent to different nodes in the 5G network with the goal introducing as little synchronicity error (uncertainty) as possible when distributing it.

• The distribution of 5G reference time information to user equipments (UEs) is designed to exploit the existing synchronized operation inherent to the 5G radio access network.

• Such a building block approach enables end-to-end time synchronization for industrial applications communication services running over 5G system. FIGURE 1 illustrates gNB SFN transmissions. The gNB maintains the acquired 5G reference time on an ongoing basis and periodically projects the value it will have when a specific reference point in the system frame structure. For example, as shown in FIGURE 1, the gNB may project the value occurring at the gNB Antenna Reference Point (ARP) at the end of the zth System Frame Number (SFNz)), which is shown at reference point tR.

The gNB then transmits the projected reference time value and the corresponding reference point (the value of SFNz) in a Radio Resource Control (RRC) message. The message is transmitted during SFN _X and received by a UE in advance of t _R . It is broadcasted to all UEs in a System Information Block 9 (SIB9) message or transmitted to an individual UE in a unicast DLInformationTransfer message.

The message used to send the 5G reference time information may also contain an uncertainty value to indicate to the UE the expected error (uncertainty) that the indicated 5G reference time value (applicable to the reference point t _R ) is expected to have. The uncertainty value reflects (a) the accuracy with which a gNB implementation can ensure that the indicated reference time corresponding to reference point t _R (the end of SFNz) will reflect the actual time when that reference point occurs at the ARP and (b) the accuracy with which the reference time can be acquired by the gNB.

The uncertainty introduced by (a) is implementation specific but is expected to be negligible and is, therefore, not further considered.

The reference time information is transmitted in the RRC information element (IE) ReferenceTimelnfo. The details are shown below.

ReferenceTimelnfo information element

Propagation Delay Compensation (PDC)

In an industrial use case where the provision of industrial clock synchronization service is supported through the 5GS, the 5GS is, in practice, only allowed to contribute a portion of the maximum end-to-end synchronicity budget (uncertainty budget) allowed for any given TSN Grandmaster clock. There are many uncertainty components in the 5GS, including the UE internal synchronization error budget, and the synchronization error budget associated with delivering the 5G internal clock to the user plane function (UPF) and the UE. The biggest 5GS synchronization error introduced is when the 5G internal clock is delivered to a UE from the gNB via the Uu interface. It occurs on the air interface and is due to the error from unknown propagation delays. In some large cells, the propagation delay from the gNB to the UE can be 1 us or larger (i.e., the distance from the gNB to the UE is 300 meters or more). Without any PDC applied to the 5G internal clock, it is not possible to meet stringent clock synchronization service performance requirements, for example, those shown in the TABLE 1.

The range of uncertainty for the most demanding synchronization requirement for a single Uu interface is shown in TABLE 2 below and was agreed at 3GPP TSG-RAN WG2 #113-e to meet performance requirements in TABLE 1. Two scenarios are listed to represent a general wide area deployment and a local deployment area. Table 2. Time synchronization error budget for single Uu interface

In 3GPP Rel-15/Rel-16, the legacy uplink (UL) transmission timing adjustment (i.e., timing advanced, TA) can be re-used to estimate and compensate the propagation delay. 3GPP Timing Advance (TA) command is utilized in cellular communication for UL transmission synchronization and it is an implementation variant of a Round Trip Time (RTT) measurement. Theoretically, the dynamic part of the TA, i.e., NTA is equal to (2 x propagation delay) considering the same propagation delay value applies to both downlink (DL) and UL directions. Since the TA command is transmitted to the UE mainly via the Medium Access Control (MAC) control element (CE), the UE can derive the propagation delay. The challenges of the TA method are that due to various implementation inaccuracies in transmit timing and reception timing at gNB and UE, it introduces up-to 540 ns uncertainty to determine the DL propagation delay on a single Uu interface based on Rel-15/Rel-16 implementation requirements. See, Rl-1901470, Reply LS on TSN requirements evaluation, RANI, 3GPP TSG-RAN WG1 Ad-Hoc Meeting 1901 Taipei, Taiwan, January 21-25, 2019.

Thus, there is a need to introduce a new PDC method to meet the most demanding synchronization requirement in Rel-17. The Rel-17 RAN work item “Enhanced Industrial Internet of Things (loT) and ultra-reliable and low latency communication (URLLC) support for NR” has the following objective related to PDC:

Enhancements for support of time synchronization: a. RAN impacts of SA2 work on uplink time synchronization for TSN, if any. [RAN2] b. Propagation delay compensation enhancements (including mobility issues, if any). [RAN2, RANI, RAN3, RAN4]

One potential method is to enhance the TA-based method with finer granularity TA commands and requirements. Another potential method is to leverage the legacy multi-RTT positioning method. This legacy method makes use of, for example, the UE Receiver-Transmitter (Rx-Tx) time difference measurements and DL-Positioning Reference Signal-Reference Signal Received Power (DL-PRS-RSRP) of DL signals received from multiple Transmission Reception Points (TRPs) as measured by the UE, and the measured gNB Rx-Tx time difference measurements and Uplink-Sounding Reference Signal-Reference Signal Received Power (UL- SRS-RSRP) at multiple TRPs of UL signals transmitted from the UE. The measurements are used to determine the RTT at the positioning server which are used to estimate the location of the UE.

The new RTT based delay compensation method is illustrated in FIGURE 2 and leverages the legacy multi-RTT positioning method as follows:

. UE transmits an uplink frame i and records the transmission time as t1.

. gNB receives uplink frame i and records the time of arrival of the first detected path as t3.

. gNB transmits a downlink frame j to the UE, and records transmission time as t2.

. UE receives downlink frame j and records the time of arrival of the first detected path as t4.

• The following calculations are performed in the UE and gNB, respectively: i) UE RX-TX diff= t4- t1 ii) gNB Rx-Tx diff= t3- 12. This quantity can be positive or negative depending on the whether gNB transmits the DL frame before or after receiving the UL frame.

• Propagation delay can be calculated as follows: Round Trip Time (RTT)= (gNB Rx - Tx time difference) + (UE Rx - Tx time difference). The propagation delay is one half of the RTT.

There are two variants of the method, depending on which node calculates the RTT and the other node delivers its Rx-TX difference.

1. UE-side PDC: The gNB delivers the gNB Rx - Tx time difference to the UE and the UE calculates the round-trip time RTT to obtain the propagation delay.

2. gNB-side PDC: The UE delivers the UE Rx - Tx time difference to the gNB and the gNB calculates the round-trip time RTT to obtain the propagation delay. gNB Pre-Compensation for All UEs in a Cell

UE-specific PDC introduces overhead, which includes, for example, the reference signals and RRC messages to deliver the measurement report individually for each UE of concern. As such, it is beneficial, from the system point of view, to have as few UE-specific PDCs as possible.

A broadcasted and pre-compensated reference time information is an efficient configuration. Suppose the tightest synchronization error/inaccuracy budget allocated to propagation delay for all UEs in the cell is ± X nanoseconds (ns). Corresponding to the budget of X ns, the distance covered by the radio wave is estimated as D = C*X (ignore non-line-of-sight effect), where C denotes the speed of light in meters per ns.

• An uncompensated reference time information from the gNB means that those UEs, whose distance to the gNB is within [0, D], would have Uu interface synchronization error of [0, X] ns. Thus, without pre-compensation, the subset of UEs located more than distance D meters away would require propagation delay compensation individually.

• On the other hand, a smart gNB implementation would broadcast a pre- compensated reference time information with X ns (i.e., the indicated time in the SIB9 message is X ns before the actual internal gNB clock time). In this way, those UEs, whose distance to the gNB is within [0, 2* D], would have Uu interface synchronization error of [-X, X] ns. Thus, with pre-compensation of X ns to SIB9 message, only the subset of UEs located more than distance 2*D away would require propagation delay compensation individually.

Thus, with pre-compensation to SIB9 message, the signalling overhead for per-UE propagation delay compensation is reduced since the UEs located with distance [0, 2*D] away from gNB no longer need UE-specific propagation delay compensation.

To sum up, the gNB can pre-compensate the reference time in SIB9 as long as the gNB is aware of the tightest Uu interface requirements for UEs in the cell. UE-specific propagation delay compensation is still necessary for UEs located too far away even with gNB pre-compensation.

CU-DU Split and Reference Time Delivery

FIGURE 3 illustrates the gNB split architecture. In the gNB split architecture, the Centralized Unit (CU) receives information over Next Generation Application Protocol (NGAP) on the N2 interface. The System Information Blocks (SIBs) are distributed to the Distributed Unit (DU) over F1 Application Protocol (F1 AP) on the F1 interface, and the DU handles the scheduling and transmission to the Uu interface.

For the RRC broadcast message of reference time information (i.e., SIB9), the message is generated at the CU and passed to DU for transmission, but the DU can overwrite/refresh/re- encode the field time in the IE RefereneceTimelnfo-r 16 before transmission over the air. It is possible to overwrite because SIB9 is not encrypted by the CU. The reason to modify time is that the gNB clock is located at the DU and there is an unknown, unexpected, and/or varying delay between CU and DU. Even though CU can pre-compensate the delay between CU and DU when setting time in the CU message to DU, it may be inaccurate. It is preferable to allow DU to overwrite the time (if possible). It is also allowed that the DU generates the SIB9 on its own.

For the RRC unicast message of reference time information (i.e., DLInformationTransfer), the message is also generated at the CU but encrypted. The CU can request the DU to deliver the accurate reference time information either on demand or by a periodic reporting, as specified in 3GPP TS 38.473 clause 9.2.11.

There currently exist certain challenge(s), however. For example, for network to pre- compensate all UEs in a cell with a broadcast message, the network must be aware of all UEs time synchronization target in the cell so that the tightest value can be derived and used in the pre- compensation. It has agreed in 3GPP RAN2#114 that there are some benefits for NG-RAN to receive the time synchronization error budget available for the NG-RAN for Uu interface to fulfil the time sync accuracy request. However, the information on the time sync accuracy budget (in addition to, for example, the cell size, etc.) are known only at the CU. Therefore, it is only the CU that is aware of whether it makes sense to have a pre-compensation for all UEs in a cell and, if so, how much the pre-compensation amount should be.

SUMMARY

Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges. For example, methods and systems are provided for computing the pre- compensated amount (i.e., χ nanoseconds) of reference time information in a split architecture.

According to certain embodiments, a method for network pre-compensation of reference time information by a DU or CU of a network node in a split architecture includes determining a reference time, t2. A pre-compensation amount, A, is obtained, and a message is generated that includes an adjusted reference time for transmission to at least one UE. The adjusted reference time is based on the reference time and the pre-compensation amount, and the DU obtains the pre- compensation amount from the CU or the CU obtains the reference time from the DU.

According to certain embodiments, a DU or CU of a network node in a split architecture includes processing circuitry configured to determine a reference time, t2, and obtain a pre- compensation amount, X. The processing circuitry is configured to generate a message that includes an adjusted reference time for transmission to at least one UE. The adjusted reference time is based on the reference time and the pre-compensation amount, and the DU obtains the pre- compensation amount from the CU or the CU obtains the reference time from the DU. According to certain embodiments, a method for network pre-compensation of reference time information by a UE includes receiving a message including an adjusted reference time. The adjusted reference time is based on a reference time, t2, and a pre-compensation amount, X. The message is received from a DU or CU of a network node in a split architecture.

According to certain embodiments, a UE for network pre-compensation of reference time information includes processing circuitry configured to receive a message including an adjusted reference time. The adjusted reference time is based on a reference time, t2, and a pre- compensation amount, X. The message is received from a DU or CU of a network node in a split architecture.

Certain embodiments may provide one or more of the following technical advantage(s). For example, certain embodiments may provide a technical advantage of enabling the network to pre-compensate the accurate reference time information broadcasted (e.g., in SIB 9) while also be able to perform the propagation delay compensation for specific UEs, depending on the synchronization targets for all UEs in the cell. This allows the network to reduce the number of UEs that require per-UE propagation delay compensation and thus reducing the signalling overhead (e.g., reference signals) over the Uu interface.

Other advantages may be readily apparent to one having skill in the art. Certain embodiments may have none, some, or all of the recited advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosed embodiments and their features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 illustrates gNB SFN transmissions;

FIGURE 2 illustrates an RTT based delay compensation method;

FIGURE 3 illustrates the gNB split architecture;

FIGURE 4 illustrates example signaling in which a CU determines to perform pre- compensation and transmits the decision to the DU, according to certain embodiments;

FIGURE 5 illustrates example signaling in which the DU transmits time information to the CU for performing pre-compensation by the CU, according to certain embodiments;

FIGURE 6 illustrates an example communication system, according to certain embodiments; FIGURE 7 illustrates an example UE, according to certain embodiments;

FIGURE 8 illustrates an example network node, according to certain embodiments;

FIGURE 9 illustrates a block diagram of a host, according to certain embodiments;

FIGURE 10 illustrates a virtualization environment in which functions implemented by some embodiments may be virtualized, according to certain embodiments;

FIGURE 11 illustrates a host communicating via a network node with a UE over a partially wireless connection, according to certain embodiments;

FIGURE 12 illustrates a method for network pre-compensation of reference time information by a DU or CU of a network node in a split architecture, according to certain embodiments; and

FIGURE 13 illustrates a method for network pre-compensation of reference time information by a UE, according to certain embodiments.

DETAILED DESCRIPTION

Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

For the purpose of time synchronization in a cell of a radio network, only those UEs with the need of Uu interface time synchronization are of concern, although in general there may also exist UEs in the cell that do not require Uu interface time synchronization. Also, in a cell, there may be idle UEs (i.e., in RRC-IDLEstate), inactive UEs (i.e., in RRC INACTIVE state) and connected UEs (i.e., in RRC-CONNECTED state). Thus, for the rest of the description, unless otherwise stated, ‘UE’ refers to an RRC-connected UE which has the need of Uu interface time synchronization.

CU Transmits the Decision to DU

FIGURE 4 illustrates example signaling 100 in which a CU 105 determines to perform pre- compensation and transmits the decision to the DU 110, according to certain embodiments. In this scenario, it is assumed that the CU 105 decides that a pre-compensation of e.g., X nanoseconds of all UEs 115 in a cell is needed. In particular embodiments, this decision may be based on, for example, the time synchronization error budget available for the Uu interface for each UE 115 that have synchronization needs, the cell size, location of the TRP(s), etc. After computing or knowing the sync targets for UEs 115 (e.g. all UEs) in a cell, the CU 105 performs gNB pre-compensation for UEs 115 (e.g. all UEs) in a cell by transmitting a message with a reference time, t2, an amount of χ nanoseconds, or both to DU 110. There are two methods for transmitting the amount of X nanoseconds to the DU 110, as shown in FIGURE 4. First, according to a particular embodiment, the CU 105 generates the SIB9 message on its own with information from the DU 110 and transmits the SIB9 message to the DU, at 120 A. Such information may include, for example, the delay between the CU 105 and the DU 110 as estimated by the DU 110. In this scenario, the SIB9 message 120A includes t2 and A nanoseconds. In a particular embodiment, the DU 110 may overwrite the t2 in the SIB9 message with a new t2, at 125 A, and transmit the SIB9 message to the UE, at 130A. In another particular embodiment, the DU 110 may generate t2 on its own, at 125B, and transmit the SIB9 message with the generated t2, at 130B.

In still another particular embodiment, the CU 105 may transmit an indication to the DU 110 that the SIB9 transmitted at 120A shall not be overwritten by the DU 110. In this scenario, the DU 110 shall not generate the SIB9 on its own or overwrite the information with its own t2.

According to other embodiments, the CU 105 may rely on the DU 110 to generate the intended broadcast message. In this scenario, the CU 105 sends the amount of pre-compensation, e.g., X nanoseconds, to the DU 110, in message 120B. This information can be sent in a F1AP message such as, for example, a F1 Setup RESPONSE, agNB-CU CONFIGURATION UPDATE, or a gNB-DU CONFIGURATION UPDATE ACKNOWLEDGE.

The DU 110 generates the SIB9 message and can adjust the time based on the pre- compensated amount, X, received from CU 105. For example, upon receiving message 120B, the DU 110 overwrites, refresh, or re-encodes the time field in the SIB9 with a value of t2 - X nanoseconds, in which t2 is the time at the DU. More precisely, U is the start or end time of a specific DL frame. A typical example of t2 is the time at the SFN boundary at or immediately after the ending boundary of the Si-window in which SIB9 is transmitted from the DU 110 according to the clock at the DU 110.

In another alternative embodiment, upon receiving message 120B, the DU 110 stores the value X nanoseconds and at the next time the DU 110 decides to broadcast the reference time information in SIB9, the DU 110 encodes the time field in the SIB9 with a value of t2 - X nanoseconds, in which t2 is the time at the DU 110.

In another particular embodiment, one or more of the following may be true: • This pre-compensation of X nanoseconds is static/fixed and can be configured in the DU 110.

• There is a validity duration of this pre-compensation of X nanoseconds. For DU 110, upon receiving this information and after some period of time (either fixed or also transmitted by the CU 105), the DU 110 considers that there is no need for the pre-compensation either by discarding the pre-compensation information of X nanosecond or considering that the value X is equal to zero.

• The value of X nanoseconds is configurable by the CU 105. The CU 105 can configure it to a new value or de-configure it (either setting to zero or explicitly indicating DU 110 to discard it).

One example of the F1AP implementation of the embodiments in this section is to update the TS 38.473 9.3.1.42 gNB-CU System Information as described in more detail below with regard to Table 3, where the newly added field is in the last row.

DU Transmits the Time Information to CU

FIGURE 5 illustrates example signaling 200 in which the DU 110 transmits time information to the CU 105 for performing pre-compensation by the CU 105, according to certain embodiments.

According to certain embodiments, the CU 105 decides that a pre-compensation of e.g., X nanoseconds of all UEs 115 in a cell is needed. This decision may be based on information such as, for example, the time synchronization error budget available for the Uu interface, the cell size, location of the TRP(s), etc. It is assumed that, in a particular embodiment, the CU 105 requests the DU 110 to deliver the accurate reference time information, e.g. as specified in clause 9.2.11 of 3GPP TS 38.473.

In a particular embodiment, at 205, the DU transmits the estimated delay between CU 105 and DU 110 and reference time information at the DU 110. In a particular embodiment, for example, the estimated delay is the time, Y nanoseconds, it needs to transmit a message from CU 105 to DU 110. The CU 105 then encodes the SIB9 with the pre-compensation amount, e.g., t1 - Y - X nanoseconds, also taking into account the delay between CU 105 and DU 110. In this scenario, t1 is the start or end time of a specific DL frame. One typical example includes t1 corresponding to the SFN boundary at or immediately after the ending boundary of the Si-window in which SIB9 is generated/transmitted from the CU 105. In this scenario, t1-Y is the t2 in the example embodiments described above. In a further particular embodiment, the DU 110 transmits the reference time pre- compensated with the delay between CU 105 and DU 110. In other words, using the above example, the DU 110 transmits the time t1 - Y nanoseconds directly to the CU 105.

In another particular embodiment, before or upon the CU 105 sending this encoded SIB9 message, the CU 105 transmits/indicates to the DU 110 that the SIB9 shall not be overwritten and the DU 110 shall not generate the SIB9 on its own. In a further particular embodiment, the indication is static/fixed and can be configured in the DU 110. In still another particular embodiment, there is a validity duration associated with the indication. For DU 110, upon receiving this information and after some period of time (either fixed or also transmitted by the CU 105), the DU 110 considers that it is allowed to overwrite. Whether it is allowed or not allowed to overwrite is configurable by the CU, in a particular embodiment.

Inter-operability with a Previous Release DU

In a particular embodiment, the previously described assistance information (a pre- compensated amount of X nanoseconds, and a flag that the DU shall not overwrite the reference time) can be sent to a previous release DU. In this example, it is a Rel-17 CU that communicates with a Rel-16 DU.

In a particular embodiment, the Rel-17 defined additions are defined in a new IE group that is assigned with criticality Reject, as shown in Error! Reference source not found.. This means that, when the Rel-16 DU receives this updated info from the Rel-17, the new IE grouped procedure is rejected, and the Rel-17 is aware of that. Otherwise, the new IE group is ignored by the Rel-16 DU, and this may lead to mis-alignment if the DU overwrites the SIB9 with an uncompensated time while the CU understands that all UEs in the cell have a pre-compensated time. In the example, the UEs within the distance between [ D, 2*D] will not get per-UE propagation delay compensation from the CU and lead to that the time synchronization target is not reached.

In a further particular embodiment, if the Rel-17 CU receives, from a DU, a rejection of the assistance information related to the reference time information, then the Rel-17 CU understands that the DU does not comprehend the Information Element and, thus, cannot perform the pre-compensation. Instead, the CU performs the per-UE propagation delay compensation for a subset of all UEs, which may include UE set A. In the example, it is the UEs whose distance is larger than D. In a further particular embodiment, if the Rel-17 CU does not receive a rejection from a DU on the assistant information of the reference time information, then the Rel-17 CU understands that the DU can perform the pre-compensation, and the CU performs per-UE propagation delay compensation for a subset of set A such as, for example, the UEs whose distance is larger than 2*D.

In the above two embodiments that include per-UE propagation delay compensation, the CU delivers RRC unicast reference time (with no pre-compensation) for the said subset of UEs and triggers a per-UE propagation delay compensation by either TA-based or RTT-based methods.

Methods for Identifying UEs to Perform UE-specific Propagation Delay Compensation

In the discussion above, a simplified calculation off) = C x X was used, with X being equal to the minimum of Uu interface accuracy requirement among the UEs in the cell. An example of a more accurate analysis is shown below.

In general, for a z-th UE with Uu interface synchronization accuracy target of A _i , the UE is considered synchronized if the difference between actual time T _{actual, UE, i} and the determined time T _i at the UE is smaller than A _i , i.e., |T _i - T _{actual, UE, i} | < A _i , where T _{actual, UE, i} = T _{actual, gNB} + T _p,i , and T _p,i is the true propagation time for the z-th UE. It is noted that ‘<’ can be changed to ‘<=’ if desired. For a UE that does not perform propagation delay compensation, the determined time T _i at the z-th UE is equal to the time information (T _signal ) signalled by the gNB, T _i = T _signal , where the time information may be carried in a broadcast message or a UE-specific message. Conversely, for a UE that performs propagation delay compensation, the determined time T _i at the z-th UE is set to T _i = T _signal + T _p,est,i , where T _signal is the time information signalled by the gNB and T _p,est,i is the estimated propagation delay at the z-th UE.

Synchronized Without Propagation Delay Compensation

Without propagation delay compensation, the UEs with | T _i - T _{actual, UE, i} | = |T _signal - T _{actual, UE,i} | < A _i are synchronized, as follows: o If gNB does not pre-compensate the signalled time, then: T _signal = T _actual,gNB , where T _actual,gNB is the actual time at the gNB side. |T _signal - T _{actual, UE, i} | = |T _actuai,gNB - (T _actual,gNB + T _p,i ) | . Thus, UEs with T _p,i < A _i can be considered synchronized. Ignoring non-line-of-sight effect, a UE with propagation delay T _p,i is located T _p,i x C from the gNB. Thus, if the i-th UE located no more than A _i x C from the gNB can be considered synchronized. o If gNB performs pre-compensation, then T _signal = T _actual,gNB + X, where X is the amount of pre-compensation. | T _signal - T _{actual, UE, i} | = | (T _{actual, gNB} + χ) - (T _{actual, gNB} + T _p,i ) | = |X - T _p,i | . Thus, UEs with |X - T _p,i | < A _i can be considered synchronized. Ignoring non-line-of-sight effect, a UE with propagation delay T _p,i is located T _p,i x C from the gNB. Thus, if the i-th UE located no more than (A _i + X) x C from the gNB can be considered synchronized. Note that X=0 also covers the case where the gNB does not pre-compensate.

• In a particular embodiment, gNB sets , if the gNB can determine or estimate the minimum of Uu interface accuracy requirements among all UEs. For example, the gNB may receive Uu interface accuracy requirement A _i of i-th UE from a core network node for all UEs.

• In another particular embodiment, the gNB can estimate T _p,i + A _i for each UE, and then take the minimum among them, i.e., . The gNB can estimate propagation delay T _p,i of i-th UE based on the timing advance for this UE.

• In another particular embodiment, the gNB picks a value X so that the number of UEs that require per-UE propagation delay compensation is minimized. The i-th UE requires the per-UE propagation delay compensation if T _p,i — (A _i + X) * C > 0 where the gNB can estimate propagation delay T _p,i of i-th UE based on the timing advance for this UE. This procedure can be expressed as the below equation. The operation | . | is to compute the cardinality, i.e., the number of elements in a set.

• X* = arg min X | {i | T _p,i — (A _i + X) * C > 0} |

While, in general, the time synchronization procedure is applied to UEs in connected state, UEs in an idle state or inactive state can also receive broadcast messages, including SIB9. Thus, even if the i-th UE is in idle state or inactive state, the i-th UE can have 5GS synchronized time if the UE is located no more than distance (A _i + X) x C from the gNB. This implies that such UE do not need to switch to RRC-CONNECTED state in order to perform time synchronization procedure, thus saving UE power as well as gNB signalling burden. To allow the i-th idle or inactive UE to determine if it is synchronized without UE-specific propagation delay compensation, the gNB may include the cell-common compensation X (ns) in the broadcast message, e.g., include X (ns) in SIB9.

Assuming that an idle or inactive UE receives its distance information from gNB, e.g., obtained from stored information, or the UE estimates the distance information using idle mode positioning methods to estimate, the UE can combine the distance estimation with X and its accuracy target A _i to decide if the UE can stay idle or inactive without losing synchronicity.

While it is possible to set a UE-specific pre-compensation value X. it is simpler to have a common X that applies to all UEs in the cell so that only one X value needs to be determined and can be incorporated into a broadcast message. Herein, it is assumed that X is cell-common. If a UE-specific X _i is used, the analysis can be simply extended with X _i for the i-th UE.

Identify UEs that Need Propagation Delay Compensation

For UEs that do not satisfy the above conditions, then explicit propagation delay compensation is needed in a UE-specific manner. According to certain embodiments, the gNB can estimate if the condition |X — T _p,i | < A _i is satisfied by combining the following information:

(a) Accuracy requirement A _i : The gNB may receive Uu interface accuracy requirement A _i of i-th UE from a core network node. Alternatively, the i-th UE may report its A _i value to the gNB, e.g., via RRC message, MAC message, etc.

(b) Propagation time T _p,i of the i-th UE: The gNB can use a variety of methods and signaling to obtain the estimation of T _p,i value. For example, for UEs in connected mode, the gNB can estimate T _p,i using the i-th UE’s timing advance value. Alternatively, the gNB may perform propagation delay compensation using a UE measurement report (e.g., UE RxTxTimeDiff). For UEs in inactive or idle mode, if any history of timing advance value or propagation delay estimate is stored, the gNB can use the historic value as an estimate. If the estimated T _p,i by gNB is not adequately accurate (e.g., the TA value is too coarse, or historical TA value is outdated), the gNB can account for this by including a margin 8.

The gNB is aware of the X value it used in time information signalling. Thus, the gNB can identify the UEs with |X — T _p,i | > A _i in the cell as those that require UE-specific propagation delay compensation. Consequently, the gNB can trigger UE-specific propagation delay compensation for the selected UE(s). FIGURE 6 shows an example of a communication system 300 in accordance with some embodiments. In the example, the communication system 300 includes a telecommunication network 302 that includes an access network 304, such as a radio access network (RAN), and a core network 306, which includes one or more core network nodes 308. The access network 304 includes one or more access network nodes, such as network nodes 310a and 310b (one or more of which may be generally referred to as network nodes 310), or any other similar 3 ^rd Generation Partnership Project (3GPP) access node or non-3GPP access point. The network nodes 310 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 312a, 312b, 312c, and 312d (one or more of which may be generally referred to as UEs 312) to the core network 306 over one or more wireless connections.

Example wireless communications over a wireless connection include transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 300 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. The communication system 300 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

The UEs 312 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes 310 and other communication devices. Similarly, the network nodes 310 are arranged, capable, configured, and/or operable to communicate directly or indirectly with the UEs 312 and/or with other network nodes or equipment in the telecommunication network 302 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in the telecommunication network 302.

In the depicted example, the core network 306 connects the network nodes 310 to one or more hosts, such as host 316. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 306 includes one more core network nodes (e.g., core network node 308) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 308. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function (SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and/or a User Plane Function (UPF).

The host 316 may be under the ownership or control of a service provider other than an operator or provider of the access network 304 and/or the telecommunication network 302, and may be operated by the service provider or on behalf of the service provider. The host 316 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio/video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.

As a whole, the communication system 300 of FIGURE 6 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and/or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and/or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.

In some examples, the telecommunication network 302 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 302 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 302. For example, the telecommunications network 302 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and/or Massive Machine Type Communication (mMTC)/Massive loT services to yet further UEs. In some examples, the UEs 312 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 304 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 304. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

In the example, the hub 314 communicates with the access network 304 to facilitate indirect communication between one or more UEs (e.g., UE 312c and/or 312d) and network nodes (e.g., network node 310b). In some examples, the hub 314 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 314 may be a broadband router enabling access to the core network 306 for the UEs. As another example, the hub 314 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 310, or by executable code, script, process, or other instructions in the hub 314. As another example, the hub 314 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 314 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 314 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 314 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, the hub 314 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.

The hub 314 may have a constant/persistent or intermittent connection to the network node 310b. The hub 314 may also allow for a different communication scheme and/or schedule between the hub 314 and UEs (e.g., UE 312c and/or 312d), and between the hub 314 and the core network 306. In other examples, the hub 314 is connected to the core network 306 and/or one or more UEs via a wired connection. Moreover, the hub 314 may be configured to connect to an M2M service provider over the access network 304 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 310 while still connected via the hub 314 via a wired or wireless connection. In some embodiments, the hub 314 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to the network node 310b. In other embodiments, the hub 314 may be a non- dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 310b, but which is additionally capable of operating as a communication start and/or end point for certain data channels.

FIGURE 7 shows a UE 400 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded/integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.

A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).

The UE 400 includes processing circuitry 402 that is operatively coupled via a bus 404 to an input/output interface 406, a power source 408, a memory 410, a communication interface 412, and/or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in FIGURE 7. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.

The processing circuitry 402 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 410. The processing circuitry 402 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 402 may include multiple central processing units (CPUs).

In the example, the input/output interface 406 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and/or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 400. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.

In some embodiments, the power source 408 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 408 may further include power circuitry for delivering power from the power source 408 itself, and/or an external power source, to the various parts of the UE 400 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 408. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 408 to make the power suitable for the respective components of the UE 400 to which power is supplied.

The memory 410 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 410 includes one or more application programs 414, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 416. The memory 410 may store, for use by the UE 400, any of a variety of various operating systems or combinations of operating systems.

The memory 410 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and/or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 410 may allow the UE 400 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 410, which may be or comprise a device-readable storage medium.

The processing circuitry 402 may be configured to communicate with an access network or other network using the communication interface 412. The communication interface 412 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 422. The communication interface 412 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 418 and/or a receiver 420 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 418 and receiver 420 may be coupled to one or more antennas (e.g., antenna 422) and may share circuit components, software or firmware, or alternatively be implemented separately.

In the illustrated embodiment, communication functions of the communication interface 412 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and/or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio (NR), UMTS, WiMax, Ethernet, transmission control protocol/intemet protocol (TCP/IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.

Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 412, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).

As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.

A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, amotion detector, a thermostat, a smoke detector, a door/window sensor, a flood/moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or item- tracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and/or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 400 shown in FIGURE 7.

As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another UE and/or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation.

In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and/or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.

FIGURE 8 shows a network node 500 in accordance with some embodiments.

As used herein, network node refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a UE and/or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)).

Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS). Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and/or Minimization of Drive Tests (MDTs).

The network node 500 includes a processing circuitry 502, a memory 504, a communication interface 506, and a power source 508. The network node 500 may be composed of multiple physically separate components (e.g., aNodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 500 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 500 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 504 for different RATs) and some components may be reused (e.g., a same antenna 510 may be shared by different RATs). The network node 500 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 500, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 500.

The processing circuitry 502 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node 500 components, such as the memory 504, to provide network node 500 functionality.

In some embodiments, the processing circuitry 502 includes a system on a chip (SOC). In some embodiments, the processing circuitry 502 includes one or more of radio frequency (RF) transceiver circuitry 512 and baseband processing circuitry 514. In some embodiments, the radio frequency (RF) transceiver circuitry 512 and the baseband processing circuitry 514 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 512 and baseband processing circuitry 514 may be on the same chip or set of chips, boards, or units.

The memory 504 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device-readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by the processing circuitry 502. The memory 504 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and/or other instructions capable of being executed by the processing circuitry 502 and utilized by the network node 500. The memory 504 may be used to store any calculations made by the processing circuitry 502 and/or any data received via the communication interface 506. In some embodiments, the processing circuitry 502 and memory 504 is integrated.

The communication interface 506 is used in wired or wireless communication of signaling and/or data between anetwork node, access network, and/or UE. As illustrated, the communication interface 506 comprises port(s)/terminal(s) 516 to send and receive data, for example to and from a network over a wired connection. The communication interface 506 also includes radio front- end circuitry 518 that may be coupled to, or in certain embodiments a part of, the antenna 510. Radio front-end circuitry 518 comprises filters 520 and amplifiers 522. The radio front-end circuitry 518 may be connected to an antenna 510 and processing circuitry 502. The radio front- end circuitry may be configured to condition signals communicated between antenna 510 and processing circuitry 502. The radio front-end circuitry 518 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 518 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 520 and/or amplifiers 522. The radio signal may then be transmitted via the antenna 510. Similarly, when receiving data, the antenna 510 may collect radio signals which are then converted into digital data by the radio front-end circuitry 518. The digital data may be passed to the processing circuitry 502. In other embodiments, the communication interface may comprise different components and/or different combinations of components. In certain alternative embodiments, the network node 500 does not include separate radio front-end circuitry 518, instead, the processing circuitry 502 includes radio front-end circuitry and is connected to the antenna 510. Similarly, in some embodiments, all or some of the RF transceiver circuitry 512 is part of the communication interface 506. In still other embodiments, the communication interface 506 includes one or more ports or terminals 516, the radio front-end circuitry 518, and the RF transceiver circuitry 512, as part of a radio unit (not shown), and the communication interface 506 communicates with the baseband processing circuitry 514, which is part of a digital unit (not shown).

The antenna 510 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. The antenna 510 may be coupled to the radio front-end circuitry 518 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In certain embodiments, the antenna 510 is separate from the network node 500 and connectable to the network node 500 through an interface or port.

The antenna 510, communication interface 506, and/or the processing circuitry 502 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by the network node. Any information, data and/or signals may be received from a UE, another network node and/or any other network equipment. Similarly, the antenna 510, the communication interface 506, and/or the processing circuitry 502 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and/or signals may be transmitted to a UE, another network node and/or any other network equipment.

The power source 508 provides power to the various components of network node 500 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 508 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 500 with power for performing the functionality described herein. For example, the network node 500 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 508. As a further example, the power source 508 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail. Embodiments of the network node 500 may include additional components beyond those shown in FIGURE 8 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, the network node 500 may include user interface equipment to allow input of information into the network node 500 and to allow output of information from the network node 500. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 500.

FIGURE 9 is a block diagram of a host 600, which may be an embodiment of the host 316 of FIGURE 6, in accordance with various aspects described herein.

As used herein, the host 600 may be or comprise various combinations hardware and/or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 600 may provide one or more services to one or more UEs.

The host 600 includes processing circuitry 602 that is operatively coupled via a bus 604 to an input/output interface 606, a network interface 608, a power source 610, and a memory 612. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 4 and 5, such that the descriptions thereof are generally applicable to the corresponding components of host 600.

The memory 612 may include one or more computer programs including one or more host application programs 614 and data 616, which may include user data, e.g., data generated by a UE for the host 600 or data generated by the host 600 for a UE. Embodiments of the host 600 may utilize only a subset or all of the components shown. The host application programs 614 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FL AC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 614 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 600 may select and/or indicate a different host for over-the-top services for a UE. The host application programs 614 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time Messaging Protocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.

FIGURE 10 is a block diagram illustrating a virtualization environment 700 in which functions implemented by some embodiments may be virtualized.

In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 700 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.

Applications 702 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein.

Hardware 704 includes processing circuitry, memory that stores software and/or instructions executable by hardware processing circuitry, and/or other hardware devices as described herein, such as a network interface, input/output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 706 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 708a and 708b (one or more of which may be generally referred to as VMs 708), and/or perform any of the functions, features and/or benefits described in relation with some embodiments described herein. The virtualization layer 706 may present a virtual operating platform that appears like networking hardware to the VMs 708.

The VMs 708 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 706. Different embodiments of the instance of a virtual appliance 702 may be implemented on one or more of VMs 708, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

In the context ofNFV, a VM 708 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 708, and that part of hardware 704 that executes that VM, be it hardware dedicated to that VM and/or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context ofNFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 708 on top of the hardware 704 and corresponds to the application 702.

Hardware 704 may be implemented in a standalone network node with generic or specific components. Hardware 704 may implement some functions via virtualization. Alternatively, hardware 704 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 710, which, among others, oversees lifecycle management of applications 702. In some embodiments, hardware 704 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 712 which may alternatively be used for communication between hardware nodes and radio units.

FIGURE 11 shows a communication diagram of a host 802 communicating via a network node 804 with a UE 806 over a partially wireless connection in accordance with some embodiments.

Example implementations, in accordance with various embodiments, of the UE (such as a UE 312a of FIGURE 6 and/or UE 400 of FIGURE 7), network node (such as network node 310a of FIGURE 6 and/or network node 500 of FIGURE 8), and host (such as host 316 of FIGURE 6 and/or host 600 of FIGURE 9) discussed in the preceding paragraphs will now be described with reference to FIGURE 11.

Like host 600, embodiments of host 802 include hardware, such as a communication interface, processing circuitry, and memory. The host 802 also includes software, which is stored in or accessible by the host 802 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 806 connecting via an over-the-top (OTT) connection 850 extending between the UE 806 and host 802. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 850.

The network node 804 includes hardware enabling it to communicate with the host 802 and UE 806. The connection 860 may be direct or pass through a core network (like core network 306 of FIGURE 6) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.

The UE 806 includes hardware and software, which is stored in or accessible by UE 806 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 806 with the support of the host 802. In the host 802, an executing host application may communicate with the executing client application via the OTT connection 850 terminating at the UE 806 and host 802. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 850 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 850.

The OTT connection 850 may extend via a connection 860 between the host 802 and the network node 804 and via a wireless connection 870 between the network node 804 and the UE 806 to provide the connection between the host 802 and the UE 806. The connection 860 and wireless connection 870, over which the OTT connection 850 may be provided, have been drawn abstractly to illustrate the communication between the host 802 and the UE 806 via the network node 804, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

As an example of transmitting data via the OTT connection 850, in step 808, the host 802 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 806. In other embodiments, the user data is associated with a UE 806 that shares data with the host 802 without explicit human interaction. In step 810, the host 802 initiates a transmission carrying the user data towards the UE 806. The host 802 may initiate the transmission responsive to a request transmitted by the UE 806. The request may be caused by human interaction with the UE 806 or by operation of the client application executing on the UE 806. The transmission may pass via the network node 804, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step 812, the network node 804 transmits to the UE 806 the user data that was carried in the transmission that the host 802 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 814, the UE 806 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 806 associated with the host application executed by the host 802.

In some examples, the UE 806 executes a client application which provides user data to the host 802. The user data may be provided in reaction or response to the data received from the host 802. Accordingly, in step 816, the UE 806 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input/output interface of the UE 806. Regardless of the specific manner in which the user data was provided, the UE 806 initiates, in step 818, transmission of the user data towards the host 802 via the network node 804. In step 820, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 804 receives user data from the UE 806 and initiates transmission of the received user data towards the host 802. In step 822, the host 802 receives the user data carried in the transmission initiated by the UE 806.

One or more of the various embodiments improve the performance of OTT services provided to the UE 806 using the OTT connection 850, in which the wireless connection 870 forms the last segment. More precisely, the teachings of these embodiments may improve one or more of, for example, data rate, latency, and/or power consumption and, thereby, provide benefits such as, for example, reduced user waiting time, relaxed restriction on file size, improved content resolution, better responsiveness, and/or extended battery lifetime.

In an example scenario, factory status information may be collected and analyzed by the host 802. As another example, the host 802 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 802 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 802 may store surveillance video uploaded by a UE. As another example, the host 802 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host 802 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and/or transmitting data.

In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 850 between the host 802 and UE 806, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host 802 and/or UE 806. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 850 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 850 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 804. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host 802. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 850 while monitoring propagation times, errors, etc.

FIGURE 12 illustrates a method 900 for network pre-compensation of reference time information by a DU or CU of a network node 310 in a split architecture, according to certain embodiments. The method begins at step 902 when the DU or CU determines a reference time, t2. At step 904, the DU or CU obtains a pre-compensation amount, X. At step 906, the DU or CU generates a message including an adjusted reference time for transmission to at least one UE 312. The adjusted reference time is based on the reference time and the pre-compensation amount. The method includes the DU obtaining the pre-compensation amount from the CU or the CU obtaining the reference time from the DU.

In a particular embodiment, the reference time, t2, is a start or an end time of a downlink frame associated with a boundary of a window in which the message is transmitted to the at least one UE.

In a particular embodiment, the pre-compensation amount, A, is an amount of time associated with a synchronization error allocated to propagation delay for a plurality of UEs in a cell. In a particular embodiment, the adjusted reference time is t2-X.

In a particular embodiment, the message comprises a broadcast message for transmission to the plurality of UEs in the cell.

In a particular embodiment, X is an amount of time associated with a synchronization error allocated to a particular UE.

In a particular embodiment, the method is performed by the DU of the network node and wherein determining the pre-compensation amount, X, comprises receiving the pre-compensation amount, X, from the CU.

In a particular embodiment, t2 is a time at the DU, and the method includes calculating, by the DU, the adjusted reference time as t2-X.

In a particular embodiment, prior to calculating t2-X, the method includes determining whether a validity duration timer associated with the pre-compensation amount, X, has not expired. When the validity duration timer has not expired, t2-X is calculated using the pre-compensation amount, X, received from the CU. When the validity duration timer has expired, t2-X is calculated using a value of zero for the pre-compensation amount, X.

In a particular embodiment, X is received from the CU via a F1 Application Protocol message, and the method includes encoding t2-x in a time field of a SIB9 message and transmitting the SIB9 message to the at least one UE.

In a particular embodiment, prior to receiving the pre-compensation amount, X, the method includes transmitting, to the CU, information indicating an amount of time delay, t1, between the CU and the DU.

In a particular embodiment, the method is performed by the CU of the network node and determining the reference time, t2, comprises receiving the reference time, t2, from the DU.

In a particular embodiment, determining the pre-compensation amount, X, comprises calculating the pre-compensation amount, X.

In a particular embodiment, prior to calculating the pre-compensation amount, X, the method includes receiving from DU, information indicating an amount of time delay, t1, between the CU and the DU.

In a particular embodiment, calculating the pre-compensation amount, X, includes receiving, from a core network, a synchronization error for each of a plurality of UEs and generating the pre-compensation amount, X, based on the synchronization error for each of the plurality of UEs. The pre-compensation amount, X, is synchronization error for the cell. In a particular embodiment, the method includes sending t2-X to the DU for transmission to the at least one UE.

In a particular embodiment, t2-X is transmitted to the DU in a SIB9 message or a Fl Application Protocol message.

In a particular embodiment, the method includes transmitting, to the DU, an indication that the SIB9 message is not to be overwritten.

In a particular embodiment, the method includes receiving a rejection message from the DU, and the rejection message indicates that the DU has not used t2-X for the at least one UE.

In a particular embodiment, the method includes performing propagation delay compensation for the at least one UE based on the rejection message.

In a particular embodiment, the method includes sending the message including t2-x to the at least one UE.

In a particular embodiment, the message is sent to the at least one UE via a SIB9 message.

FIGURE 13 illustrates a method 1000 for network pre-compensation of reference time information by a UE 312, according to certain embodiments. The method includes receiving, at step 1002, a message including an adjusted reference time that is based on a reference time, t2, and a pre-compensation amount, X. The message is received from a DU or a CU of a network node (310) in a split architecture.

In a particular embodiment, the reference time, t2, is a start or an end time of a downlink frame associated with a boundary of a window in which the message is transmitted to the at least one UE.

In a particular embodiment, the pre-compensation amount, X, is an amount of time associated with a synchronization error allocated to propagation delay for a plurality of UEs in a cell.

In a particular embodiment the message comprises a broadcast message transmitted to a plurality of UEs in the cell, the plurality of UEs including the UE.

In a particular embodiment, X is an amount of time associated with a synchronization error allocated to the UE.

In a particular embodiment, t2 is a time at the DU, and the adjusted reference time is t2-X.

In a particular embodiment, the message comprises a SIB9 message and t2-x is encoded in a time field of the SIB9 message.

In a particular embodiment, the message comprises an F1 Application Protocol message. Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and/or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and/or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.

In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and/or by end users and a wireless network generally. EXAMPLE EMBODIMENTS

Group A Example Embodiments

Example Embodiment A1. A method by a user equipment for network pre-compensation of reference time information in split architecture, the method comprising: any of the user equipment steps, features, or functions described above, either alone or in combination with other steps, features, or functions described above.

Example Embodiment A2. The method of the previous embodiment, further comprising one or more additional user equipment steps, features or functions described above.

Example Embodiment A3. The method of any of the previous embodiments, further comprising: providing user data; and forwarding the user data to a host computer via the transmission to the network node.

Group B Example Embodiments

Example Embodiment B1. A method performed by a network node for network pre- compensation of reference time information in split architecture, the method comprising: any of the network node steps, features, or functions described above, either alone or in combination with other steps, features, or functions described above.

Example Embodiment B2. The method of the previous embodiment, further comprising one or more additional network node steps, features or functions described above.

Example Embodiment B3. The method of any of the previous embodiments, further comprising: obtaining user data; and forwarding the user data to a host or a user equipment.

Group C Example Embodiments

Example Embodiment C1. A method for network pre-compensation of reference time information by a central unit of a network node in a split architecture, the method comprising: transmitting, to a distributed unit of the network node, timing information that includes or is at least partially based on a pre-compensated time value.

Example Embodiment C2. The method of Example Embodiment C1, wherein the distributed unit is configured to: adjust a reference time based on the pre-compensated time value; and transmit the adjusted reference time to at least one wireless device.

Example Embodiment C3. The method of Example Embodiment C2, wherein the distributed unit is configured to transmit the adjusted reference time via a broadcast message.

Example Embodiment C4a. The method of Example Embodiment C3, wherein the broadcast message is transmitted to a group of wireless devices that includes the wireless device.

Example Embodiment C4b. The method of Example Embodiment C4a, wherein each wireless device in the group of wireless devices are is in an RRC Connected state.

Example Embodiment C5. The method of any one of Example Embodiments C3 to C4b, wherein the broadcast message comprises a SIB9.

Example Embodiment C6. The method of Example Embodiment C5, wherein the distributed unit is configured to encode the time information in a time field of the SIB9.

Example Embodiment C7. The method of Example Embodiment C1, further comprising adjusting a reference time based on the pre-compensated time value, and wherein the transmitted timing information includes the adjusted reference time.

Example Embodiment C8. The method of Example Embodiment C7, wherein the timing information is transmitted to the distributed unit in a SIB9 message.

Example Embodiment C9. The method of Example Embodiment C8, transmitting, to the distributed unit, an indication that the SIB9 message is not to be overwritten.

Example Embodiment C10. The method of any one of Example Embodiments C7 to C9, wherein prior to transmitting the timing information to the distributed unit, the method comprises receiving, from the distribute unit, information indicating an amount of time delay between the central unit and the distributed unit.

Example Embodiment C11. The method of Example Embodiment C10, further comprising determining the pre-compensated time value based on the time delay between the central unit and the distributed unit.

Example Embodiment C12. The method of any one of Example Embodiments C1 to C11, wherein the pre-compensated time value is associated with an amount of time delay between the central unit and the distributed unit.

Example Embodiment C13. The method of any one of Example Embodiments C1 to C12, further comprising receiving a rejection message from the distributed unit, the rejection message indicating that the distributed has not used the timing information to adjust a reference time for at least one wireless device.

Example Embodiment C14.The method of Example Embodiment C13, further comprising performing propagation delay compensation for the at least one wireless device based on the rejection message.

Example Embodiment C15.The method of any one of Example Embodiments C13 to C14, further comprising transmitting an adjusted reference time to the at least one wireless device, the adjusted reference time based on the propagation delay compensation performed by the central unit.

Example Embodiment C16.The method of any one of Example Embodiments C1 to C15, wherein the network node comprises a gNodeB (gNB).

Example Embodiment C17. The method of any of the previous Example Embodiments, further comprising: obtaining user data; and forwarding the user data to a host or a user equipment.

Example Embodiment C18. A network node comprising processing circuitry configured to perform any of the methods of Example Embodiments C1 to C17.

Example Embodiment C19. A computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments C1 to Cl 7.

Example Embodiment C20. A computer program product comprising computer program, the computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments C1 to C17.

Example Embodiment C21. A non-transitory computer readable medium storing instructions which when executed by a computer perform any of the methods of Example Embodiments C1 to C17.

Group D Example Embodiments

Example Embodiment D1. A method for network pre-compensation of reference time information by a distributed unit of a network node in a split architecture, the method comprising: receiving, from a central unit of the network node, a pre-compensated time value; and transmitting, to at least one wireless device, time information that is at least partially based on the pre- compensated time value.

Example Embodiment D2. The method of Example Embodiment D1, further comprising adjusting a reference time based on the pre-compensated time value, wherein the time information transmitted to the group of wireless devices comprises the reference time that is adjusted based on the pre-compensated time value.

Example Embodiment D3. The method of any one of Example Embodiments D1 to D2, wherein the time information is transmitted via a broadcast message.

Example Embodiment D4a. The method of Example Embodiment D3, wherein the broadcast message is transmitted to a group of wireless devices that includes the wireless device.

Example Embodiment D4b. The method of Example Embodiment D4a, wherein each wireless device in the group of wireless devices are is in an RRC Connected state.

Example Embodiment D5. The method of any one of Example Embodiments D3 to D4b, wherein the broadcast message comprises a SIB9.

Example Embodiment D6. The method of Example Embodiment D5, further comprising encoding the time information in a time field of the SIB9.

Example Embodiment D7. The method of Example Embodiment D1, wherein receiving the pre-compensated time value from the central unit comprises receiving the pre-compensated time value in a SIB9 message.

Example Embodiment D8. The method of Example Embodiment D7, receiving an indication from the central unit that the SIB9 message is not to be overwritten.

Example Embodiment D9. The method of any one of Example Embodiments D7 to D8, wherein prior to receiving the pre-compensated time value, the method comprises transmitting, to the central unit information indicating an amount of time delay between the central unit and the distributed unit.

Example Embodiment D10. The method of any one of Example Embodiments D1 to

D9, wherein a pre-compensated time value is associated with an amount of time delay between the central unit and the distributed unit.

Example Embodiment D11. The method of any one of Example Embodiments D1 to

DIO, wherein the network node comprises a gNodeB (gNB).

Example Embodiment D12. The method of any of the previous Example Embodiments, further comprising: obtaining user data; and forwarding the user data to a host or a user equipment.

Example Embodiment D13. A network node comprising processing circuitry configured to perform any of the methods of Example Embodiments D1 to D12.

Example Embodiment D14. A computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments D1 to D12.

Example Embodiment D15. A computer program product comprising computer program, the computer program comprising instructions which when executed on a computer perform any of the methods of Example Embodiments D1 to D12.

Example Embodiment D16. A non-transitory computer readable medium storing instructions which when executed by a computer perform any of the methods of Example Embodiments D1 to D12. Group E Example Embodiments

Example Embodiment E1. A user equipment for network pre-compensation of reference time information in split architecture, comprising: processing circuitry configured to perform any of the steps of any of the Group A Example Embodiments; and power supply circuitry configured to supply power to the processing circuitry.

Example Embodiment E2. A network node for network pre-compensation of reference time information in split architecture, the network node comprising: processing circuitry configured to perform any of the steps of any of the Group B, C, and D Example Embodiments; power supply circuitry configured to supply power to the processing circuitry.

Example Embodiment E3. A user equipment (UE) for network pre-compensation of reference time information in split architecture, the UE comprising: an antenna configured to send and receive wireless signals; radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry; the processing circuitry being configured to perform any of the steps of any of the Group A Example Embodiments; an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

Example Embodiment E4. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a communication interface and processing circuitry, the communication interface and processing circuitry of the UE being configured to perform any of the steps of any of the Group A Example Embodiments to receive the user data from the host.

Example Embodiment E5. The host of the previous Example Embodiment, wherein the cellular network further includes a network node configured to communicate with the UE to transmit the user data to the UE from the host.

Example Embodiment E6. The host of the previous 2 Example Embodiments, wherein: the processing circuitry of the host is configured to execute a host application, thereby providing the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application. Example Embodiment E7. A method implemented by a host operating in a communication system that further includes a network node and a user equipment (UE), the method comprising: providing user data for the UE; and initiating a transmission carrying the user data to the UE via a cellular network comprising the network node, wherein the UE performs any of the operations of any of the Group A embodiments to receive the user data from the host.

Example Embodiment E8. The method of the previous Example Embodiment, further comprising: at the host, executing a host application associated with a client application executing on the UE to receive the user data from the UE.

Example Embodiment E9. The method of the previous Example Embodiment, further comprising: at the host, transmitting input data to the client application executing on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application.

Example Embodiment E10. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a cellular network for transmission to a user equipment (UE), wherein the UE comprises a communication interface and processing circuitry, the communication interface and processing circuitry of the UE being configured to perform any of the steps of any of the Group A Example Embodiments to transmit the user data to the host.

Example Embodiment E11. The host of the previous Example Embodiment, wherein the cellular network further includes a network node configured to communicate with the UE to transmit the user data from the UE to the host.

Example Embodiment E12. The host of the previous 2 Example Embodiments, wherein: the processing circuitry of the host is configured to execute a host application, thereby providing the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application.

Example Embodiment E13. A method implemented by a host configured to operate in a communication system that further includes a network node and a user equipment (UE), the method comprising: at the host, receiving user data transmitted to the host via the network node by the UE, wherein the UE performs any of the steps of any of the Group A Example Embodiments to transmit the user data to the host.

Example Embodiment E14. The method of the previous Example Embodiment, further comprising: at the host, executing a host application associated with a client application executing on the UE to receive the user data from the UE.

Example Embodiment E15. The method of the previous Example Embodiment, further comprising: at the host, transmitting input data to the client application executing on the UE, the input data being provided by executing the host application, wherein the user data is provided by the client application in response to the input data from the host application.

Example Embodiment E16. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to provide user data; and a network interface configured to initiate transmission of the user data to a network node in a cellular network for transmission to a user equipment (UE), the network node having a communication interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations of any of the Group B, C, and D Example Embodiments to transmit the user data from the host to the UE.

Example Embodiment E17. The host of the previous Example Embodiment, wherein: the processing circuitry of the host is configured to execute a host application that provides the user data; and the UE comprises processing circuitry configured to execute a client application associated with the host application to receive the transmission of user data from the host.

Example Embodiment E18. A method implemented in a host configured to operate in a communication system that further includes a network node and a user equipment (UE), the method comprising: providing user data for the UE; and initiating a transmission carrying the user data to the UE via a cellular network comprising the network node, wherein the network node performs any of the operations of any of the Group B, C, and D Example Embodiments to transmit the user data from the host to the UE.

Example Embodiment E19.The method of the previous Example Embodiment, further comprising, at the network node, transmitting the user data provided by the host for the UE.

Example Embodiment E20. The method of any of the previous 2 Example Embodiments, wherein the user data is provided at the host by executing a host application that interacts with a client application executing on the UE, the client application being associated with the host application.

Example Embodiment E21. A communication system configured to provide an over-the- top service, the communication system comprising: a host comprising: processing circuitry configured to provide user data for a user equipment (UE), the user data being associated with the over-the-top service; and a network interface configured to initiate transmission of the user data toward a cellular network node for transmission to the UE, the network node having a communication interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations of any of the Group B, C, and D Example Embodiments to transmit the user data from the host to the UE.

Example Embodiment E22. The communication system of the previous Example Embodiment, further comprising: the network node; and/or the user equipment.

Example Embodiment E23. A host configured to operate in a communication system to provide an over-the-top (OTT) service, the host comprising: processing circuitry configured to initiate receipt of user data; and a network interface configured to receive the user data from a network node in a cellular network, the network node having a communication interface and processing circuitry, the processing circuitry of the network node configured to perform any of the operations of any of the Group B, C, and D Example Embodiments to receive the user data from a user equipment (UE) for the host.

Example Embodiment E24. The host of the previous 2 Example Embodiments, wherein: the processing circuitry of the host is configured to execute a host application, thereby providing the user data; and the host application is configured to interact with a client application executing on the UE, the client application being associated with the host application.

Example Embodiment E25.The host of the any of the previous 2 Example Embodiments, wherein the initiating receipt of the user data comprises requesting the user data.

Example Embodiment E26. A method implemented by a host configured to operate in a communication system that further includes a network node and a user equipment (UE), the method comprising: at the host, initiating receipt of user data from the UE, the user data originating from a transmission which the network node has received from the UE, wherein the network node performs any of the steps of any of the Group B, C, and D Example Embodiments to receive the user data from the UE for the host.

Example Embodiment E27. The method of the previous Example Embodiment, further comprising at the network node, transmitting the received user data to the host.