Patent Description:
In a typical wireless communication network, UEs, also known as wireless communication devices, mobile stations, stations (STA) and/or wireless devices, communicate via a Radio access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into service areas or cell areas, with each service area or cell area being served by a radio network node such as an access node e.g. a Wi-Fi access point or a radio base station (RBS), which in some radio access technologies (RAT) may also be called, for example, a NodeB, an evolved NodeB (eNodeB) and a gNodeB (gNB). The service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node operates on radio frequencies to communicate over an air interface with the UEs within range of the access node. The radio network node communicates over a downlink (DL) to the UE and the UE communicates over an uplink (UL) to the radio network node. The radio network node may be a distributed node comprising a remote radio unit and a separated baseband unit.

A Universal Mobile Telecommunications System (UMTS) is a third generation telecommunication network, which evolved from the second generation (<NUM>) Global System for Mobile Communications (GSM). The UMTS terrestrial radio access network (UTRAN) is essentially a RAN using wideband code division multiple access (WCDMA) and/or High-Speed Packet Access (HSPA) for communication with UEs. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for present and future generation networks and UTRAN specifically, and investigate enhanced data rate and radio capacity. In some RANs, e.g. as in UMTS, several radio network nodes may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC) or a base station controller (BSC), which supervises and coordinates various activities of the plural radio network nodes connected thereto. The RNCs are typically connected to one or more core networks.

Specifications for the Evolved Packet System (EPS) have been completed within the <NUM>rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, such as <NUM> networks. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long-Term Evolution (LTE) radio access network, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a 3GPP radio access technology wherein the radio network nodes are directly connected to the EPC core network. As such, the Radio Access Network (RAN) of an EPS has an essentially "flat" architecture comprising radio network nodes connected directly to one or more core networks.

With the emerging <NUM> technologies also known as new radio NR, the use of very many transmit- and receive-antenna elements is of great interest as it makes it possible to utilize beamforming, such as transmit-side and receive-side beamforming. Transmit-side beamforming means that the transmitter can amplify the transmitted signals in a selected direction or directions, while suppressing the transmitted signals in other directions. Similarly, on the receive-side, a receiver can amplify signals from a selected direction or directions, while suppressing unwanted signals from other directions.

Beamforming allows the signal to be stronger for an individual connection. On the transmit-side this may be achieved by a concentration of the transmitted power in the desired direction(s), and on the receive-side this may be achieved by an increased receiver sensitivity in the desired direction(s). This beamforming enhances throughput and coverage of the connection. It also allows reducing the interference from unwanted signals, thereby enabling several simultaneous transmissions over multiple individual connections using the same resources in the time-frequency grid, so-called multi-user Multiple Input Multiple Output (MIMO).

Two new work items for mobility enhancements in LTE and NR have started in 3GPP in release <NUM>. The main objectives of the work items are to improve the robustness at handover and to decrease the interruption time at handover.

One problem related to robustness at handover (HO) is that the HO Command, such as RRCConnectionReconfiguration with mobilityControllnfo and RRCReconfiguration with a reconfigurationWithSync field, is normally sent when the radio conditions for the UE are already quite bad. That may lead to that the HO Command may not reach the UE in time if the message is segmented or there are retransmissions.

In LTE and NR, different solutions to increase mobility robustness have been discussed in the past. One solution discussed in NR is called "conditional handover" or "early handover command". In order to avoid the undesired dependence on the serving radio link upon the time (and radio conditions) where the UE should execute the handover, the possibility to provide RRC signalling for the handover to the UE earlier should be provided. To achieve this, it should be possible to associate the HO command with a condition e.g. based on radio conditions possibly similar to the ones associated to an A3 event, where a given neighbour becomes X db better than target. As soon as the condition is fulfilled, the UE executes the handover in accordance with the provided handover command.

Such a condition could e.g. be that the quality of the target cell or beam becomes X dB stronger than the serving cell. A threshold Y used in a preceding measurement reporting event should then be chosen lower than the one in the handover execution condition. This allows the serving cell to prepare the handover upon reception of an early measurement report and to provide the RRCConnectionReconfiguration with mobilityControllnfo at a time when the radio link between the source cell and the UE is still stable. The execution of the handover is done at a later point in time (and threshold) which is considered optimal for the handover execution.

<FIG> depicts an example with just a serving and a target cell and a Conditional handover execution. In practice there may often be many cells or beams that the UE reported as possible candidates based on its preceding radio resource management (RRM) measurements. The network should then have the freedom to issue conditional handover commands for several of those candidates. The RRCConnectionReconfiguration for each of those candidates may differ e.g. in terms of the HO execution condition, reference signal (RS) to measure and threshold to exceed, as well as in terms of the random access (RA) preamble to be sent when a condition is met.

While the UE evaluates the condition, it should continue operating per its current RRC configuration, i.e., without applying the conditional HO command. When the UE determines that the condition is fulfilled, it disconnects from the serving cell, applies the conditional HO command and connects to the target cell. These steps are equivalent to the current, instantaneous handover execution.

Conditional handover is described in CR R2-<NUM>.

A Conditional Handover (CHO) is defined as a handover that is executed by the UE when one or more handover execution conditions are met. The UE starts evaluating the execution condition(s) upon receiving the CHO configuration, and stops evaluating the execution condition(s) once the execution condition(s) is met.

CHO is not supported for N2 based handover in this release of the specification.

As in intra-NR RAN handover, in intra-NR RAN CHO, the preparation and execution phase of the conditional handover procedure is performed without involvement of the 5GC; i.e. preparation messages are directly exchanged between gNBs. The release of the resources at the source gNB during the conditional handover completion phase is triggered by the target gNB. The figure below depicts the basic conditional handover scenario where neither the AMF nor the UPF changes:.

The UE can be configured with Dual Connectivity (DC), communicating both via a Master Cell Group (MCG) and a Secondary Cell Group (SCG). When the UE is configured with dual connectivity, the UE is configured with two Medium Access Control (MAC) entities: one MAC entity for the MCG and one MAC entity for the SCG. In Multi-Radio Dual Connectivity (MR-DC) the cell groups are located in two different logical nodes, i.e. different NG-RAN nodes, possibly connected via a non-ideal backhaul, one providing NR access and the other one providing either E-UTRA or NR access. One node acts as the Master Node (MN) and the other as the Secondary Node (SN). The MN and SN are connected via a network interface and at least the MN is connected to the core network.

The operation in MR-DC involves different reconfiguration procedures, like secondary node addition, secondary node modification, secondary node release and secondary node change.

In the following, it is shown the signalling flow from TS <NUM> v. <NUM> for the SN initiated SN change, also called PSCell Change (PC). Therein, the UE is operating in MR-DC i.e. connected to an MN and a Source SN (S-SN) and, S-SN decides to move the UE to a Target SN (T-SN), possibly based on reported measurements on S-SN and/or T-SN frequencies.

<FIG> shows an example signalling flow for the Secondary Node Change initiated by the SN:.

The objective of the invention is achieved by means of the features of the appended independent claims.

This disclosure relates to the case where the SN PSCell is changed from one cell to another secondary cell, and even more specifically a conditional PSCell Change (CPC) which is being standardized in the release (rel)-<NUM> work item for mobility enhancements. In rel-<NUM> only the case intra-SN case without MN involvement for CPC is supported, i.e. where S-SN and T-SN are in the same node as in <FIG>. That means that the secondary cell is changed, but both the old and the new secondary cell are in the same node. On the other hand, embodiments herein are not limited to this case only since in further releases inter-SN change based on CPC may be introduced.

RAN2 has agreed to support Conditional PSCell Change (CPC) procedure. Therein a UE operating in Multi-Radio Dual Connectivity (MR-DC) receives an radio resource control (RRC) Reconfiguration, e.g. an RRCReconfiguration message, containing an SCG configuration, e.g. an secondaryCellGroup of IE CellGroupConfig, with a reconfigurationWithSync that is stored and associated to an execution condition, e.g. a condition like an A3 event configuration, so that the stored message is only applied upon the fulfilment of the execution condition, upon which the UE would perform a PSCell change. The following are the agreements related to the procedure:.

As part of developing embodiments herein one or more problems were identified. A first problem embodiments herein address concerns the scenario where the UE is operating in EUTRAN NG-RAN - Dual Connectivity (EN-DC) i.e. having a connection with a Master Node (MN) which is an LTE eNB, and a Secondary Node (SN) which is an NR gNB; and, being configured with a Conditional PSCell Change (CPC) for an NR cell as target candidate. The UE is then monitoring execution condition(s) for triggering a CPC procedure.

The problem relates to the following agreements from RAN2#109e:.

If SRB3 is configured, all communication occurs within the same RAT, particular the transmission of a complete message in NR format when CPC is executed (i.e. an RRCReconfigurationComplete transmitted via SRB3 to NR). However, when SRB3 is not configure, the UE needs to use the LTE's SRB1 to deliver any message that may later need to be forwarded to SN / NR side, assuming a procedure similar to legacy would be applicable here (i.e. MN forwards the RRCReconfigurationComplete to the target SN, via the SgNB Reconfiguration Complete message over the inter-node interface).

When CPC is configured, an RRCReconfiguration* is generated in the SN (i.e. at the NR gNB) including the execution condition configuration and an RRCReconfiguration*** per target candidate, see <FIG>, to then be provided to the MN. This is somewhat equivalent to step <NUM> in <FIG>: SN Change - SN initiated (TS <NUM>). , where a version of the SgNB Addition Request Acknowledge message (to be used in CPC) from the T-SN to the MN may contain the RRCReconfiguration*.

That RRCReconfiguration* is then encapsulated in an nr-SecondaryCellGroupConfig to be included in an RRCConnectionReconfiguration** in LTE format. Upon reception of that RRCConnectionReconfiguration** in LTE format the UE detects the inclusion of the nr-SecondaryCellGroupConfig and applies the RRCReconfiguration* that is encapsulated, and as part of the procedure creates an RRCReconfigurationComplete* message (in response to the RRCReconfiguration*). The UE then responds the MN with an RRCConnectionReconfigurationComplete** message, including inside the RRCReconfigurationComplete* message generated in response to the RRCReconfiguration* as a way to acknowledge the reception of the SN message with CPC configuration. At this procedure the UE starts monitoring CPC execution conditions.

When an execution condition associated to a target candidate for CPC is fulfilled, the UE applies RRCReconfiguration*** message in NR format. As part of that procedure the UE generates an RRCReconfigurationComplete*** (that needs to be transmitted to LTE) according to the agreements and perform random access with the target candidate cell (which is in the target SN (T-SN) illustrated below simply as NR). However, that message RRCReconfigurationComplete*** is in NR format and cannot be transmitted to LTE (or any other RAT in more general terms). This problem is illustrated in <FIG>.

A second problem embodiments herein concern is the scenario where the UE is operating in MR-DC i.e. having a connection with a Master Node (MN) which may be an NR gNB, and a Secondary Node (SN) which may be an LTE eNB; and, being configured with a Conditional PSCell Change for e.g. an LTE cell. In other words, the UE is monitoring an execution condition for a CPC procedure. In that case, upon the fulfilment of an execution condition the UE applies an RRCConnectionReconfiguration (in LTE format) and generates an RRCConnectionReconfigurationComplete that needs to be transmitted via NR. And, as in the first problem, it is not clear how that message could be transmitted to NR.

A main difference compared to the legacy procedure, i.e. PSCell Change, is that in the legacy procedure the UE receives the NR PSCell Change configuration to be applied (RRCReconfiguration) upon reception embedded within an LTE message (RRCConnectionReconfiguration). Then, upon applying the RRCReconfiguration and generating the RRCReconfigurationComplete in response, there is also the need to generate an RRCConnectionReconfigurationComplete in LTE format for the wrapper message. Hence, the RRCReconfigurationComplete in NR format can be transmitted in the RRCConnectionReconfigurationComplete that is anyway to be transmitted. However, when CPC is executed there is no RRCConnectionReconfigurationComplete to be transmitted, resulting in that communication may be interrupted or delayed, thereby, limiting or reducing the performance of the wireless communication network.

An object of embodiments herein is to provide a mechanism that improves performance in the wireless communication network.

According to embodiments herein the object is achieved by methods and nodes as claimed in claims <NUM>,<NUM>,<NUM>,<NUM>,<NUM> and <NUM>.

According to an aspect the object is achieved by providing a method performed by a UE for handling cell change of a secondary cell for the UE. The UE receives from a master node, a message of a first RAT comprising a reconfiguration message for a conditional reconfiguration of the secondary cell of a second RAT. The UE transmits to the master node, a first complete message of the second RAT embedded in another message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. The UE further transmits to the master node, upon fulfilment of a condition of the conditional reconfiguration, a second complete message of the second RAT embedded in a RRC message of the first RAT.

According to another aspect the object is achieved by providing a method performed a master node for handling cell change of a secondary cell for a UE. The master node transmits to the UE, a message of a first RAT comprising a reconfiguration message for a conditional reconfiguration of the secondary cell of a second RAT. The master node further receives from the UE, a first complete message of the second RAT embedded in another message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration; and transmits the first complete message to the secondary node. The master node further receives from the UE, a second complete message, indicating a condition fulfilled at the UE, of the second RAT embedded in a RRC message of the first RAT; and transmits the second complete message to the secondary node.

According to yet another aspect the object is achieved by providing a method performed a secondary node for handling cell change of a secondary cell for a UE. The secondary node transmits to a master node, a reconfiguration message for a conditional reconfiguration of the secondary cell of a second RAT; and receives from the master node, a first complete message of the second RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration; and further receives from the master node, a second complete message of the second RAT indicating a condition fulfilled at the UE.

It is furthermore provided herein a computer program product comprising instructions, which, when executed on at least one processor, cause the at least one processor to carry out any of the methods above, as performed by the master node, the secondary node or the UE, respectively. It is additionally provided herein a computer-readable storage medium, having stored thereon a computer program product comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the method according to any of the methods above, as performed by the master node, the secondary node, or the UE, respectively.

According to yet another aspect the object is achieved by providing a master or a secondary node configured to perform the methods in the network.

According to still another aspect the object is achieved by providing a UE configured to perform the methods by the UE.

According to yet still another aspect the object is achieved by providing a UE for handling cell change of a secondary cell for the UE. The UE is configured to receive from a master node, a message of a first RAT comprising a reconfiguration message for a conditional reconfiguraiton of the secondary cell of a second RAT, and to transmit to the master node, a first complete message of the second RAT embedded in another message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. The UE is configured to, upon fulfilment of a condition of the conditional reconfiguration, transmit to the master node, a second complete message of the second RAT embedded in a RRC message of the first RAT.

According to yet still another aspect the object is achieved by providing a master node for handling cell change of a secondary cell for a UE. The master node is configured to transmit to the UE, a message of a first RAT comprising a reconfiguration message for a conditional reconfiguration of the secondary cell of a second RAT. The master node is further configured to receive from the UE, a first complete message of the second RAT embedded in another message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. The master node is configured to transmit the first complete message to the secondary node; to receive from the UE, a second complete message, indicating a condition fulfilled at the UE, of the second RAT embedded in a RRC message of the first RAT; and to transmit the second complete message to the secondary node.

According to yet still another aspect the object is achieved by providing a secondary node for handling cell change of a secondary cell for a UE. The secondary node is configured to transmit to a master node, a reconfiguration message for a conditional reconfiguration of the secondary cell of a second RAT; and to receive from the master node, a first complete message of the second RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. The secondary node is further configured to receive from the master node a second complete message of the second RAT indicating a condition fulfilled at the UE.

Embodiments herein relate to methods and nodes for enabling secondary cell change.

The methods enable the transmission of a complete message in NR format (e.g. RRCConnectionReconfiguration) via LTE upon the execution of Conditional PSCell Change procedure i.e. in response to applying an RRCReconfiguration message. Thanks to the method it is possible to transmit an NR complete message via LTE without necessarily having to transmit an LTE complete message, which is not possible since that would require the UE to first apply an RRCConnectionReconfiguration message in LTE format, which does not happen in Conditional PSCell Change (CPC). That is different from legacy PSCell Change where the UE actually receives an RRCConnectionReconfiguration in LTE format which anyways require the transmission of an RRCConnectionReconfigurationComplete also in LTE format. Hence, that is not an issue in legacy PSCell Change when only SRB1 is configured via LTE and the UE operates in EN-DC.

However, in Conditional PSCell Change the UE receives an RRCConnectionReconfiguration in LTE format which requires the transmission of an RRCConnectionReconfigurationComplete including a first RRCReconfigurationComplete in NR format, but a second RRCReconfigurationComplete in NR format needs to be transmitted upon execution and without the method there is no way to transmit that over LTE since the network would not expect any complete message in LTE format any longer. Thanks to the method the UE transmits the NR complete message in an UL procedure via SRB1 using a message defined in LTE format that does not require a first configuration message to be transmitted.

Thus, embodiments herein improve performance in the wireless communication network.

Embodiments herein are described in the context of <NUM>/NR and LTE but the same concept can also be applied to other wireless communication system such as <NUM>/LTE and UMTS. Embodiments herein may be described within the context of 3GPP NR radio technology (3GPP TS <NUM> V15. <NUM> (<NUM>-<NUM>)), e.g. using gNB as the radio network node. It is understood, that the problems and solutions described herein are equally applicable to wireless access networks and user-equipments (UEs) implementing other access technologies and standards. NR is used as an example technology where embodiments are suitable, and using NR in the description therefore is particularly useful for understanding the problem and solutions solving the problem. In particular, embodiments are applicable also to 3GPP LTE, or 3GPP LTE and NR integration, also denoted as non-standalone NR.

Embodiments herein relate to wireless communication networks in general. <FIG> is a schematic overview depicting a wireless communication network <NUM>. The wireless communication network <NUM> comprises e.g. one or more RANs and one or more CNs. The wireless communication network <NUM> may use one or a number of different technologies, such as Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, NR, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possible implementations. Embodiments herein relate to recent technology trends that are of particular interest in <NUM> systems integrated with LTE systems, however, embodiments are also applicable in further development of the existing communication systems such as e.g. a WCDMA or a LTE system.

In the wireless communication network <NUM>, wireless devices e.g. a UE <NUM> such as a mobile station, a non-access point (non-AP) station (STA), a STA, a user equipment and/or a wireless terminal, communicate via one or more Access Networks (AN), e.g. RAN, to one or more core networks (CN). It should be understood by the skilled in the art that "UE" is a non-limiting term which means any terminal, wireless communication terminal, user equipment, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, internet of things (IoT) operable device, or node e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or even a small base station capable of communicating using radio communication with a network node within an area served by the network node.

The communication network <NUM> comprises a first radio network node <NUM> providing e.g. radio coverage over a geographical area, a first service area <NUM> i.e. a first cell, of a first radio access technology (RAT), such as NR, LTE, Wi-Fi, WiMAX or similar. The first radio network node <NUM> may be a transmission and reception point, a computational server, a base station e.g. a network node such as a base station, a Wireless Local Area Network (WLAN) access point or an Access Point Station (AP STA), an access node, an access controller, a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB), a gNodeB (gNB), a base transceiver station, a baseband unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit or node depending e.g. on the radio access technology and terminology used. The first radio network node <NUM> may alternatively or additionally be a controller node or a packet processing node or similar. The first radio network node <NUM> may be referred to as master node, source access node or a serving network node wherein the first service area <NUM> may be referred to as a serving cell, source cell or primary cell, and the first radio network node communicates with the UE <NUM> in form of DL transmissions to the UE <NUM> and UL transmissions from the UE <NUM>. The first radio network node may be a distributed node comprising a baseband unit and one or more remote radio units.

The communication network <NUM> comprises a second radio network node <NUM> providing e.g. radio coverage over a geographical area, a second service area <NUM> i.e. a second cell, of a second radio access technology (RAT), such as NR, LTE, Wi-Fi, WiMAX or similar. The second radio network node <NUM> may be a transmission and reception point, a computational server, a base station e.g. a network node such as a base station, a Wireless Local Area Network (WLAN) access point or an Access Point Station (AP STA), an access node, an access controller, a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB), a gNodeB (gNB), a base transceiver station, a baseband unit, an Access Point Base Station, a base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit or node depending e.g. on the radio access technology and terminology used. The second radio network node <NUM> may alternatively or additionally be a controller node or a packet processing node or similar. The second radio network node <NUM> may be referred to as a secondary node, a target access node or a target network node wherein the second service area <NUM> may be referred to as a target cell or secondary cell, and the second radio network node <NUM> communicates with the UE <NUM> in form of DL transmissions to the UE <NUM> and UL transmissions from the UE <NUM>. The second radio network node may be a distributed node comprising a baseband unit and one or more remote radio units. The first RAT is different than the second RAT.

It should be noted that a service area may be denoted as cell, beam, beam group or similar to define an area of radio coverage. It should further be noted that the first and second cell may be provided by the same first radio network node <NUM>.

Embodiments herein relate to a solution where the UE <NUM> is operating in dual connectivity wherein the UE <NUM> has a connection to a master node, i.e. the first radio network node <NUM> of the first RAT, and a connection to a secondary node, i.e. the second radio network node <NUM> of the second RAT. The second radio network node <NUM> transmits via the first radio network node <NUM> a reconfiguration message for a conditional reconfiguration of the secondary cell to the UE <NUM>. Since the first radio network node <NUM> is of a different RAT than the second radio network node <NUM>, the UE <NUM> receives the reconfiguration message for the conditional reconfiguration of the secondary cell of the second RAT embedded in a message of the first RAT. The UE <NUM> then transmits a first complete message of the second RAT embedded in another message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. That is, the first complete message is sent in response to the received conditional reconfiguration.

The UE may then apply the conditional reconfiguration and monitor one or more conditions of the conditional reconfiguration. Upon fulfilment of a condition of the conditional reconfiguration, the UE <NUM> then transmits to the first radio network node <NUM> a second complete message of the second RAT embedded in a radio resource control (RRC) message of the first RAT. The first radio network node <NUM> then unwraps the RRC message and forwards the second complete message to the second radio network node <NUM>. Thus, embodiments herein enable, in a dual connectivity scenario of different RATs, a change of secondary nodes improving the performance of the wireless communication network.

In the document the term LTE for the first RAT or the second RAT is equivalent to the term E-UTRA MCG.

<FIG> is combined flowchart and signalling scheme depicting embodiment herein. The UE may have a connection to the master node <NUM> of the first RAT, and a connection to the secondary node <NUM> of the second RAT.

Action <NUM>. The secondary node <NUM> transmits to the master node <NUM> a reconfiguration message for a conditional reconfiguration of the secondary cell of the second RAT. A condition may be included in the RRCReconfiguration message or RRCconnectionreconfiguration generated by the SN <NUM> for intra-SN conditional PSCell change initiated by the SN <NUM>.

Action <NUM>. The master node <NUM> transmits to the UE <NUM> the reconfiguration message embedded in a message of the first RAT.

Action <NUM>. The UE <NUM> transmits a first complete message of the second RAT embedded in another message of the first RAT, wherein the first complete message indicates that the UE <NUM> is able to comply to the conditional reconfiguration.

Action <NUM>. The master node <NUM> transmits the first complete message to the secondary node <NUM>.

Action <NUM>. The UE <NUM> monitors a condition of the conditional reconfiguration.

Action <NUM>. The UE <NUM>, upon fulfilment of the condition of the conditional reconfiguration, transmits a second complete message of the second RAT embedded in an RRC message of the first RAT.

Action <NUM>. The master node then transmits the second complete message to the secondary node <NUM>.

The method actions in the UE <NUM> for handling cell change of a secondary cell for the UE in the wireless communications network according to embodiments herein will now be described with reference to a flowchart depicted in <FIG>. The actions do not have to be taken in the order stated below, but may be taken in any suitable order. Actions performed in some embodiments are marked with dashed boxes. The UE <NUM> may have a connection to the master node <NUM> of the first RAT, and a connection to the secondary node <NUM> of the second RAT.

Action <NUM>. The UE <NUM> receives from the master node <NUM>, the message of the first RAT comprising the reconfiguration message for a conditional reconfiguration of the secondary cell of the second RAT. For example, reconfiguration of the secondary cell embedded in a first reconfiguration message of the first RAT.

The first RAT may be LTE and the second RAT may be NR. When the first RAT is LTE and the second RAT is NR, the reconfiguration message may be a RRCreconfiguration message and the message of the first RAT may be a RRCConnectionReconfiguration message.

The first RAT may be NR, and the second RAT may be LTE. When the first RAT is NR and the second RAT is LTE, the reconfiguration message may be a RRCconnectionreconfiguration message and the message of the first RAT may be a RRCreconfiguration message.

Action <NUM>. The UE <NUM> transmits to the master node <NUM>, the first complete message of the second RAT embedded in another message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration.

When the first RAT is LTE and the second RAT is NR, the first complete message of the second RAT may be a RRCreconfiguration complete message and the other message of the first RAT may be a RRCConnectionReconfiguration complete message.

When the first RAT is NR and the second RAT is LTE, the first complete message of the second RAT may be a RRCConnectionReconfiguration complete message and the other message of the first RAT is a RRCreconfiguration complete message.

Action <NUM>. The UE <NUM> may apply the conditional reconfiguration, performing an action according to the conditional reconfiguration. monitor one or more signals and compare with a condition such as signal strength threshold or the like.

Action <NUM>. The UE <NUM>, upon fulfilment of a condition of the conditional reconfiguration, transmits to the master node <NUM>, the second complete message of the second RAT embedded in a RRC message of the first RAT. The second complete message may be transmitted over a signalling radio bearer one, SRB1. The RRC message of the first RAT may be a ULInformationTransferMRDC message.

The method actions performed by the master node <NUM> for handling cell change of the secondary cell for the UE in the wireless communications network according to embodiments herein will now be described with reference to a flowchart depicted in <FIG>. The actions do not have to be taken in the order stated below, but may be taken in any suitable order.

Action <NUM>. The master node <NUM> transmits to the UE <NUM>, the message of the first RAT comprising the reconfiguration message for conditional reconfiguration of the secondary cell of the second RAT.

Action <NUM>. The master node <NUM> further receives from the UE, the first complete message of the second RAT embedded in the other message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration.

Action <NUM>. The master node <NUM> transmits the first complete message to the secondary node.

Action <NUM>. The master node <NUM> receives from the UE, the second complete message, indicating the condition fulfilled at the UE, of the second RAT embedded in the RRC message of the first RAT. The second complete message may be received over a SRB1. The RRC message of the first RAT may be a ULInformationTransferMRDC message.

Action <NUM>. The master node <NUM> then transmits the second complete message to the secondary node.

The method actions performed by the secondary node <NUM> for handling cell change of the secondary cell for the UE in the wireless communications network according to embodiments herein will now be described with reference to a flowchart depicted in <FIG>. The actions do not have to be taken in the order stated below, but may be taken in any suitable order.

Action <NUM>. The secondary node <NUM> transmits to the master node <NUM>, the reconfiguration message for the conditional reconfiguration of the secondary cell of the second RAT.

The first RAT may be LTE and the second RAT may be NR. When the first RAT is LTE and the second RAT is NR, the reconfiguration message may be a RRCreconfiguration message.

The first RAT may be NR, and the second RAT may be LTE. When the first RAT is NR and the second RAT is LTE, the reconfiguration message may be a RRCconnectionreconfiguration message.

Action <NUM>. The secondary node <NUM> receives from the master node, the first complete message of the second RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration.

When the first RAT is LTE and the second RAT is NR, the first complete message of the second RAT may be a RRCreconfiguration complete message.

When the first RAT is NR and the second RAT is LTE, the first complete message of the second RAT may be a RRCConnectionReconfiguration complete message.

Action <NUM>. The secondary node <NUM> receives from the master node, the second complete message, indicating a condition fulfilled at the UE, of the second RAT.

The document refers to a CPC configuration and procedures (like CPC execution). However, other terms may be considered as synonyms such as Conditional Reconfiguration, or Conditional Configuration (since the message that is stored and applied upon fulfilment of a condition is an RRCReconfiguration or RRCConnectionReconfiguration). Terminology-wise, one could also interpret conditional handover (CHO) in a broader sense, also covering CPC procedures.

So far, the configuration of CPC is done using the same IEs as conditional handover, which may be called at some point conditional configuration or conditional reconfiguration. The principle for the configuration is the same with configuring triggering/execution condition(s) and a reconfiguration message to be applied when the triggering condition(s) are fulfilled. The configuration IEs from TS <NUM>:.

The IE ConditionalReconfiguration is used to add, modify and release the configuration of conditional configuration.

The IE CondConfigld is used to identify a CHO or CPC configuration.

The IE CHO-ConfigToAddModList concerns a list of conditional configurations to add or modify, with for each entry the cho-ConfigId and the associated condExecutionCond and condRRCReconfig.

<FIG> is combined flowchart and signalling scheme depicting embodiment herein, wherein the UE is in MR-DC with MN LTE and SN NR.

The SN <NUM> transmits NR-SCG configuration to the MN <NUM>. The MN <NUM> transmits the LTE message for reconfiguration to the UE, for example, transmits RRCConnectionReconfiguration** including the NR-SCG configuration. The UE applies the NR-SCG configuration and generates a RRCReconfiguration complete*. The UE <NUM> includes the RRCReconfigurationComplete* within the RRCReconfigruationConnectionComplete**. The UE transmits the RRCConnectionReconfigurationComplete** with the RRCReconfiguration complete* to the MN <NUM>. The MN <NUM> transmits the RRCReconfigurationComplete* to the SN <NUM>.

The UE <NUM> may then start monitoring CPC conditions according to the conditionReconfiguration within the RRCReconfiguration*. A condition in the NR-SCG configuration may then be fulfilled for RRCReconfiguration** and e.g. a second cell such as cell-<NUM>. The UE <NUM> may then transmit an ULInformationTransferMRDC message including the RRCReconfigurationcomplete*** to the MN <NUM>. The MN <NUM> transmits RRCReconfigurationcomplete*** to the SN <NUM> and a random access procedure may be initiated.

It is herein disclosed a method in a wireless terminal (also called a User Equipment - UE) for conditional reconfiguration (e.g. Conditional PSCell Change (CPC) execution) the method comprising:.

Additionally or alternatively, the UE submits the RRCReconfigurationComplete as described above if at least one of the conditions (or combination) occurs:.

Additionally or alternatively, the UE submits the RRCReconfigurationComplete to lower layers for transmission via SRB1 if at least one of the conditions (or combination) occurs:.

Network embodiments are provided in the detailed description for this main use case wherein the UE is in EN-DC, i.e., MN LTE and SN NR.

UE and network embodiments are also provided herein for another use case (UE in MR-DC, i.e., MN NR and SN LTE).

Thus, a use case may be UE in EN-DC where MN LTE and SN NR as disclosed in <FIG>, but embodiments herein also cover where the UE <NUM> is in MR-DC with MN NR and SN LTE. It is herein disclosed a method performed by a wireless terminal (also called a User Equipment - UE) for conditional reconfiguration execution (e.g. Conditional PSCell Change (CPC) execution) the method comprising:.

Additionally or alternatively, the UE submits the RRCReconfigurationComplete as described above in the claim if at least one of the conditions (or combination) occurs:.

Example implementation in RRC specifications of NR (TS <NUM>) and LTE (TS <NUM>) for step <NUM>/
[TS <NUM>].

NOTE: If multiple NR cells are triggered in conditional configuration execution, it is up to UE implementation which one to select, e.g. the UE considers beams and beam quality to select one of the triggered cells for execution. [TS <NUM>].

The UE shall perform the following actions upon reception of the RRCReconfiguration, or upon execution of the conditional configuration (CHO or CPC):
[.

The purpose of this procedure is to transfer from the UE to E-UTRAN MR-DC dedicated information e.g. the NR RRC Measurement Report message or an NR RRCReconfigurationComplete (to be transmitted upon the CPC execution if only SRB1 is configured and the UE is operating in EN-DC).

A UE in RRC_CONNECTED initiates the UL information transfer procedure whenever there is a need to transfer MR DC dedicated information as specified in TS <NUM> [<NUM>]. the procedure is not used during an RRC connection reconfiguration involving NR connection reconfiguration, in which case the MR DC information is piggybacked to the RRCConnectionReconfigurationComplete message, except in the case the UE executes a Conditional PSCell Change.

The UE shall set the contents of the ULInformationTransferMRDC message as follows:.

It is herein disclosed a method in a first network node operating as Master Node (MN) for a UE in MR-DC configured with conditional reconfiguration (e.g. Conditional PSCell Change (CPC) execution) the method comprising:.

It is herein disclosed a method in a second network node operating as Secondary Node (SN) for a UE in MR-DC configured with conditional reconfiguration (e.g. CPC execution) the method comprising:.

Example implementation in RRC specifications of NR (TS <NUM>) and LTE (TS <NUM>) for steps <NUM>/ and <NUM>/
[TS <NUM>].

The purpose of this procedure is to modify an RRC connection, e.g. to establish/ modify/ release RBs, to perform handover, to setup/ modify/ release measurements, to add/ modify/ release SCells. As part of the procedure, NAS dedicated information may be transferred from E-UTRAN to the UE.

E-UTRAN may initiate the RRC connection reconfiguration procedure to a UE in RRC_CONNECTED. E-UTRAN applies the procedure as follows:.

The UE initiates the RRC connection reconfiguration procedure while in RRC_CONNECTED when a conditional reconfiguration (e.g. CHO) is executed i.e. upon the fulfilment of an execution condition, an associated RRCConnectionReconfiguration that is stored is applied.

If the RRCConnectionReconfiguration message does not include the mobilityControllnfo and the UE is able to comply with the configuration included in this message, the UE shall:.

The network configures the UE with one or more candidate target SpCells in the conditional configuration. The UE evaluates the condition of each configured candidate target SpCell. The UE applies the conditional configuration associated with one of the target SpCells which fulfills associated execution condition. The network provides the configuration parameters for the target SpCell in the ConditionalReconfigurationIE.

The UE performs the following actions based on a received ConditionalReconfigurationIE:.

For each condConfigld received in the condConfigToAddModList IE the UE shall:.

Note : up to <NUM> MeasId can be configured for each condConfigld. The conditional handover event of the <NUM> MeasId may have the same or different event conditions, triggering quantity, time to trigger, and triggering threshold. [TS <NUM>].

If the RRCConnectionReconfiguration message does not include the mobilityControllnfo and the UE is able to comply with the configuration included in this message, the UE shall:
[.

UE embodiments (UE in MR-DC with MN NR and SN LTE). It is herein disclosed a method in a wireless terminal (also called a User Equipment - UE) for conditional reconfiguration execution (e.g. CPC execution) the method comprising:.

Additionally or alternatively, the UE submits the RRCConnectionReconfigurationComplete as described above if at least one of the conditions (or combination) occurs:.

Additionally or alternatively, the UE submits the RRCConnectionReconfigurationComplete to lower layers for transmission via SRB1 if at least one of the conditions (or combination) occurs:.

It is herein disclosed a method in a first network node operating as Master Node (MN) for a UE in MR-DC configured with conditional reconfiguration (e.g. Conditional PSCell Change - CPC execution) the method comprising:.

It is herein disclosed a method in a second network node operating as Secondary Node (MN) for a UE in MR-DC configured with conditional reconfiguration (e.g. Conditional PSCell Change-CPC execution) the method comprising:.

The reception of the message indicates to the SN that the UE has successfully executed CPC in a target cell candidate;.

<FIG> is a block diagram depicting the MN <NUM>, in two embodiments, for handling cell change of the secondary cell for the UE <NUM>, wherein the UE has the connection to the master node of the first RAT, and the connection to the secondary node of the second RAT, e.g. for handling communication, such as handling, enabling or performing handover, in the wireless communication network <NUM> according to embodiments herein.

The MN <NUM> may comprise processing circuitry <NUM>, e.g. one or more processors, configured to perform the methods herein.

The MN <NUM> may comprise a transmitting unit <NUM>, e.g. a transmitter or a transceiver. The MN <NUM>, the processing circuitry <NUM> and/or the transmitting unit <NUM> is configured to transmit to the UE, the reconfiguration for the conditional cell change of the secondary cell of the second RAT embedded in the first reconfiguration message of the first RAT. For example, transmit to the UE <NUM> served by the MN <NUM> in the first cell <NUM>, the first RAT message. transmit an NR message including an LTE SCG configuration. In one embodiment the NR message is an RRCReconfiguration; In one embodiment the LTE SCG configuration is an RRCConnectionReconfiguration in LTE format; In one embodiment the RRCConnectionReconfiguration in LTE format contain a CPC configuration, comprising for each target candidate an execution condition configuration to be monitored (e.g. like an A3 and/or A5 event) and an RRCConnectionReconfiguration to be stored by the UE.

The MN <NUM> may comprise a receiving unit <NUM>, e.g. a receiver or a transceiver. The MN <NUM>, the processing circuitry <NUM> and/or the receiving unit <NUM> is configured to receive from the UE <NUM>, the first complete message of the second RAT embedded in the other message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. For example, receive a complete message in second RAT format embedded with a first RAT complete message in first RAT format. In one embodiment the NR message is an RRCReconfigurationComplete; In one embodiment the LTE message is an RRCConnectionReconfigurationComplete.

The MN <NUM>, the processing circuitry <NUM> and/or the transmitting unit <NUM> is configured to transmit the first complete message to the secondary node.

The MN <NUM>, the processing circuitry <NUM> and/or the receiving unit <NUM> is configured to receive from the UE, the second complete message, indicating the condition fulfilled at the UE, of the second RAT embedded in the RRC message of the first RAT. The RRC message may be ULInformationTransferMRDC message. The second complete message may be received over the SRB1.

The MN <NUM>, the processing circuitry <NUM> and/or the transmitting unit <NUM> is configured to transmit the second complete message to the secondary node.

The MN <NUM> further comprises a memory <NUM>. The memory comprises one or more units to be used to store data on, such as indications, strengths or qualities, grants, messages, execution conditions, user data, reconfiguration, configurations, scheduling information, timers, applications to perform the methods disclosed herein when being executed, and similar. The MN <NUM> comprises a communication interface <NUM> comprising transmitter, receiver, transceiver and/or one or more antennas. Thus, it is herein provided the MN for handling a cell change of the secondary cell for the UE <NUM>, wherein the UE <NUM> has the connection to the master node of the first RAT, and the connection to the secondary node of the second RAT in a wireless communications network, wherein the MN comprises processing circuitry and a memory, said memory comprising instructions executable by said processing circuitry whereby said MN is operative to perform any of the methods herein.

The methods according to the embodiments described herein for the MN <NUM> are respectively implemented by means of e.g. a computer program product <NUM> or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the MN <NUM>. The computer program product <NUM> may be stored on a computer-readable storage medium <NUM>, e.g. a universal serial bus (USB) stick, a disc or similar. The computer-readable storage medium <NUM>, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the MN <NUM>. In some embodiments, the computer-readable storage medium may be a non-transitory or transitory computer-readable storage medium.

<FIG> is a block diagram depicting the second radio network node <NUM> i.e. the secondary node <NUM>, in two embodiments, for handling cell change of the secondary cell for the UE <NUM>. For example, handling communication, e.g. handling, enabling or performing handover, in the wireless communication network <NUM> according to embodiments herein.

The secondary node <NUM> may comprise processing circuitry <NUM>, e.g. one or more processors, configured to perform the methods herein.

The secondary node <NUM> may comprise a generating unit <NUM>, e.g. a transmitter or a transceiver. The secondary node <NUM>, the processing circuitry <NUM> and/or the generating unit <NUM> may be configured to generate a first RAT e.g. LTE/E-UTRA , SCG configuration.

The secondary node <NUM> may comprise a transmitting unit <NUM>, e.g. a transmitter or a transceiver. The secondary node <NUM>, the processing circuitry <NUM> and/or the transmitting unit <NUM> is configured to transmit to the master node, the reconfiguration message for the conditional reconfiguration of the secondary cell of the second RAT, e.g. transmit the E-UTRA SCG configuration to the Master Node i.e. the first radio network node <NUM>.

The secondary node <NUM> may comprise a receiving unit <NUM>, e.g. a receiver or a transceiver. The secondary node <NUM>, the processing circuitry <NUM> and/or the receiving unit <NUM> is configured to receive from the master node, the first complete message of the second RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. receive from the MN a first E-UTRA complete message in E-UTRA format e.g. a first E-UTRA RRCConnectionReconfigurationComplete message. The reception of the message indicates to the SN that the UE has successfully received the message and is able to comply to the CPC configuration, at least the execution condition configuration(s).

The secondary node <NUM>, the processing circuitry <NUM> and/or the receiving unit <NUM> is further configured to receive from the master node, the second complete message of the second RAT indicating the condition fulfilled at the UE. The secondary node <NUM>, the processing circuitry <NUM> and/or a receiving unit may further be configured to receive from the MN a second E-UTRA complete message in E-UTRA format e.g. a second E-UTRA RRCConnectionReconfigurationComplete message.

The secondary node <NUM> further comprises a memory <NUM>. The memory comprises one or more units to be used to store data on, such as indications, strengths or qualities, grants, messages, execution conditions, user data, reconfiguration, configurations, scheduling information, timers, applications to perform the methods disclosed herein when being executed, and similar. The secondary node <NUM> comprises a communication interface <NUM> comprising transmitter, receiver, transceiver and/or one or more antennas. Thus, it is herein provided the SN for handling a cell change of the secondary cell for the UE <NUM>, wherein the UE <NUM> has the connection to the master node of the first RAT, and the connection to the secondary node of the second RAT in a wireless communications network, wherein the SN comprises processing circuitry and a memory, said memory comprising instructions executable by said processing circuitry whereby said SN is operative to perform any of the methods herein.

The methods according to the embodiments described herein for the secondary node <NUM> are respectively implemented by means of e.g. a computer program product <NUM> or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the secondary node <NUM>. The computer program product <NUM> may be stored on a computer-readable storage medium <NUM>, e.g. a universal serial bus (USB) stick, a disc or similar. The computer-readable storage medium <NUM>, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the secondary node <NUM>. In some embodiments, the computer-readable storage medium may be a non-transitory or transitory computer-readable storage medium.

<FIG> is a block diagram depicting the UE <NUM>, in two embodiments, for handling communication, e.g. handling, enabling or performing handover, in the wireless communication network <NUM> according to embodiments herein. Thus, it is herein disclosed the UE for handling cell change of a secondary cell for the UE <NUM>.

The UE <NUM> may comprise processing circuitry <NUM>, e.g. one or more processors, configured to perform the methods herein.

The UE <NUM> may comprise a receiving unit <NUM>, e.g. a receiver or a transceiver. The UE <NUM>, the processing circuitry <NUM> and/or the receiving unit <NUM> is configured to receive from the master node <NUM>, the message of the first RAT comprising the reconfiguration message for the conditional reconfiguration of the secondary cell of the second RAT. receives, from the first radio network node <NUM> serving the UE <NUM> in the first cell, a first RAT message including an SCG configuration of a second RAT; AND.

The UE <NUM> may comprise an applying unit <NUM>. The UE <NUM>, the processing circuitry <NUM> and/or the applying unit <NUM> may be configured to apply the conditional reconfiguration, and perform an action according to the conditional reconfiguration such as apply the SCG configuration of the second RAT e.g. reconfiguration. the UE <NUM> may apply an RRCReconfiguration in second RAT format containing CPC configuration(s), and may start monitoring conditional reconfiguration i.e. it starts to monitor the execution condition(s) (e.g. like an A3 and/or A5 event).

The UE <NUM> may comprise a transmitting unit <NUM>, e.g. a transmitter or a transceiver. The UE <NUM>, the processing circuitry <NUM> and/or the transmitting unit <NUM> is configured to transmit to the MN <NUM>, the first complete message of the second RAT embedded in the other message of the first RAT, wherein the first complete message indicates that the UE is able to comply to the conditional reconfiguration. The UE <NUM>, the processing circuitry <NUM> and/or the transmitting unit <NUM> is further configured to transmit, upon fulfilment of the condition of the conditional reconfiguration, to the master node, the second complete message of the second RAT embedded in the RRC message of the first RAT. The second complete message may be transmitted over the SRB1.

The UE <NUM> further comprises a memory <NUM>. The memory comprises one or more units to be used to store data on, such as indications, strengths or qualities, grants, indications, reconfiguration, configuration, values, scheduling information, timers, applications to perform the methods disclosed herein when being executed, and similar. The UE <NUM> comprises a communication interface <NUM> comprising transmitter, receiver, transceiver and/or one or more antennas. Thus, it is herein provided the UE for handling a cell change of the secondary cell for the UE <NUM>, wherein the UE <NUM> has the connection to the master node of the first RAT, and the connection to the secondary node of the second RAT in a wireless communications network, wherein the UE comprises processing circuitry and a memory, said memory comprising instructions executable by said processing circuitry whereby said UE is operative to perform any of the methods herein.

The methods according to the embodiments described herein for the UE <NUM> are respectively implemented by means of e.g. a computer program product <NUM> or a computer program product, comprising instructions, i.e., software code portions, which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the UE <NUM>. The computer program product <NUM> may be stored on a computer-readable storage medium <NUM>, e.g. a universal serial bus (USB) stick, a disc or similar. The computer-readable storage medium <NUM>, having stored thereon the computer program product, may comprise the instructions which, when executed on at least one processor, cause the at least one processor to carry out the actions described herein, as performed by the UE <NUM>. In some embodiments, the computer-readable storage medium may be a non-transitory or transitory computer-readable storage medium.

In some embodiments a more general term "radio network node" is used and it can correspond to any type of radio network node or any network node, which communicates with a wireless device and/or with another network node. Examples of network nodes are NodeB, Master eNB, Secondary eNB, a network node belonging to Master cell group (MCG) or Secondary Cell Group (SCG), base station (BS), multistandard radio (MSR) radio node such as MSR BS, eNodeB, network controller, radio network controller (RNC), base station controller (BSC), relay, donor node controlling relay, base transceiver station (BTS), access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU), Remote Radio Head (RRH), nodes in distributed antenna system (DAS), core network node e.g. Mobility Switching Centre (MSC), Mobile Management Entity (MME) etc., Operation and Maintenance (O&M), Operation Support System (OSS), Self-Organizing Network (SON), positioning node e.g. Evolved Serving Mobile Location Centre (E-SMLC), Minimizing Drive Test (MDT) etc..

In some embodiments the non-limiting term wireless device or user equipment (UE) is used and it refers to any type of wireless device communicating with a network node and/or with another UE in a cellular or mobile communication system. Examples of UE are target device, device-to-device (D2D) UE, proximity capable UE (aka ProSe UE), machine type UE or UE capable of machine to machine (M2M) communication, PDA, PAD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles etc..

The embodiments are described for <NUM>. However the embodiments are applicable to any RAT or multi-RAT systems, where the UE receives and/or transmit signals (e.g. data) e.g. LTE, LTE FDD/TDD, WCDMA/HSPA, GSM/GERAN, Wi Fi, WLAN, CDMA2000 etc..

As will be readily understood by those familiar with communications design, that functions means or modules may be implemented using digital logic and/or one or more microcontrollers, microprocessors, or other digital hardware. In some embodiments, several or all of the various functions may be implemented together, such as in a single application-specific integrated circuit (ASIC), or in two or more separate devices with appropriate hardware and/or software interfaces between them. Several of the functions may be implemented on a processor shared with other functional components of a wireless device or network node, for example.

Alternatively, several of the functional elements of the processing means discussed may be provided through the use of dedicated hardware, while others are provided with hardware for executing software, in association with the appropriate software or firmware. Thus, the term "processor" or "controller" as used herein does not exclusively refer to hardware capable of executing software and may implicitly include, without limitation, digital signal processor (DSP) hardware, read-only memory (ROM) for storing software, random-access memory for storing software and/or program or application data, and non-volatile memory. Designers of communications devices will appreciate the cost, performance, and maintenance trade-offs inherent in these design choices.

With reference to <FIG>, in accordance with an embodiment, a communication system includes a telecommunication network <NUM>, such as a 3GPP-type cellular network, which comprises an access network <NUM>, such as a radio access network, and a core network <NUM>. The access network <NUM> comprises a plurality of base stations 3212a, 3212b, 3212c, such as NBs, eNBs, gNBs or other types of wireless access points being examples of the radio network node <NUM> herein, each defining a corresponding coverage area 3213a, 3213b, 3213c. Each base station 3212a, 3212b, 3212c is connectable to the core network <NUM> over a wired or wireless connection <NUM>. A first user equipment (UE) <NUM>, being an example of the UE <NUM>, located in coverage area 3213c is configured to wirelessly connect to, or be paged by, the corresponding base station 3212c. A second UE <NUM> in coverage area 3213a is wirelessly connectable to the corresponding base station 3212a.

The host computer <NUM> and the connected UEs <NUM>, <NUM> are configured to communicate data and/or signalling via the OTT connection <NUM>, using the access network <NUM>, the core network <NUM>, any intermediate network <NUM> and possible further infrastructure (not shown) as intermediaries.

The wireless connection <NUM> between the UE <NUM> and the base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE <NUM> using the OTT connection <NUM>, in which the wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may achieving both high reliability and low data interruption (<NUM> or close to <NUM>), and at the same time keep the transport network load at an acceptable low level caused by forwarding of DL data packets and thereby provide benefits such as improved battery time, and better responsiveness.

In certain embodiments, measurements may involve proprietary UE signalling facilitating the host computer's <NUM> measurements of throughput, propagation times, latency and the like.

It will be appreciated that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and apparatus taught herein. As such, the apparatus and techniques taught herein are not limited by the foregoing description and accompanying drawings. Instead, the embodiments herein are limited only by the following claims.

Claim 1:
A method performed by a user equipment, UE, (<NUM>) for handling a Conditional PSCell Change, CPC, procedure, of a secondary cell for the UE (<NUM>), the method comprising:
receiving (<NUM>) from a master node, a message of a first radio access technology, RAT, comprising a reconfiguration message for the CPC procedure of the secondary cell of a second RAT, wherein the first RAT is different than the second RAT;
transmitting (<NUM>) to the master node, a message of the first RAT comprising a first complete message of the second RAT, wherein the first complete message indicates that the UE is able to comply to the reconfiguration message; and
upon fulfilment of a condition of the CPC procedure of the secondary cell of the second RAT, transmitting (<NUM>) to the master node, a radio resource control, RRC, message of the first RAT comprising a second complete message of the second RAT.