WO2016171602A1

WO2016171602A1 - A base station, a communication entity, and methods therein, for routing a data flow related to a user equipment

Info

Publication number: WO2016171602A1
Application number: PCT/SE2016/050278
Authority: WO
Inventors: Helka-Liina Määttanen; Torsten DUDDA; Stefan Wager; Riikka Susitaival
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2015-04-20
Filing date: 2016-04-04
Publication date: 2016-10-27
Anticipated expiration: 2017-10-20

Abstract

A method performed by a base station, for controlling a data flow related to a UE is provided. The data flow is routed according to any one out of: via a cellular radio network, via a Wireless Local Area Network (WLAN) and via both the cellular radio network, and the WLAN. When the base station has obtained (301) from a communication entity, an indication about a WLAN mobility event, the base station controls (302) the data flow based on the obtained indication.

Description

A BASE STATION, A COMMUNICATION ENTITY, AND METHODS THEREIN, FOR ROUTING A DATA FLOW RELATED TO A USER EQUIPMENT.

TECHNICAL FIELD

Embodiments herein relate to a base station, a community entity and a method therein. In particular, they relate to controlling a data flow related to a user equipment.

BACKGROUND

Wireless devices are also known as e.g. communication devices, User Equipments (UE), mobile terminals, wireless terminals and/or mobile stations. Wireless devices are enabled to communicate wirelessly in a cellular communications network or wireless communication system, sometimes also referred to as a cellular radio system or cellular networks. The communication may be performed e.g. between two wireless devices, between a wireless device and a regular telephone and/or between a wireless devices and a server via a Radio Access Network (RAN) and possibly one or more core networks, comprised in the cellular communications network.

Wireless devices may further be referred to as mobile telephones, cellular telephones, computers, or surf plates with wireless capability, just to mention some further examples. The wireless devices in the present context may be, for example, portable, pocket-storable, hand-held, computer-comprised, or vehicle-mounted mobile devices, enabled to communicate voice and/or data, via the RAN, with another entity, such as another wireless devices or a server.

The cellular communications network covers a geographical area which is divided into cell areas, wherein each cell area is served by a base station, e.g. a Radio Base Station (RBS), which sometimes may be referred to as e.g. "eNB", "eNodeB", "NodeB", "B node", or BTS (Base Transceiver Station), depending on the technology and terminology used. The base stations may be of different classes such as e.g. macro eNodeB, home eNodeB or pico base station, based on transmission power and thereby also cell size. A cell is the geographical area where radio coverage is provided by the base station at a base station site. One base station, situated on the base station site, may serve one or several cells. The cells often overlap each other. Further, each base station may support one or several communication technologies. The base stations communicate over the air interface, also referred to as the cellular interface, operating on radio frequencies with the wireless devices within range of the base stations.

In 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), base stations, which may be referred to as eNodeBs or even eNBs, may be directly connected to one or more core networks.

3GPP LTE radio access standard has been written in order to support high bitrates and low latency both for uplink and downlink traffic. All data transmission is in LTE controlled by the radio base station. In modern cellular networks, the need to provide ever increasing data rates to UEs may be met by integrating different RATs at radio level. In particular, it is currently discussed better ways to integrate cellular systems such as LTE, and Wireless Local Area Network (WLAN), in particular for operator-deployed WLANs, so that throughput provided by the individual systems can be aggregated by a UE. A problem with this solution is that a data flow to a UE will probably be interrupted during mobility of the UE with Access Point (AP) change in the WLAN.

SUMMARY It is therefore an object of embodiments herein to improve the way of integrating communications networks such as a cellular networks and a WLAN.

According to a first aspect of embodiments herein, the object is achieved by a method performed by a base station, for controlling a data flow related to a UE. The data flow is routed according to any one out of: via a cellular radio network, via a Wireless Local Area Network, WLAN, and via both the cellular radio network, and the WLAN.

When the base station has obtained from a communication entity, an indication about a WLAN mobility event, the base station controls the data flow based on the obtained indication.

According to a second aspect of embodiments herein, the object is achieved by a method performed by a communication entity, for assisting a base station in controlling a data flow related to a user equipment, UE. The data flow is routed according to any one out of: via a cellular radio network, via a Wireless Local Area Network, WLAN, and via both the cellular radio network, and the WLAN. The method comprising: The communication entity estimates a WLAN mobility event. The communication entity assists the base station in controlling the data flow by sending an indication about the WLAN mobility event to the base station. According to a third aspect of embodiments herein, the object is achieved by a base station for controlling a data flow related to a user equipment, UE. The data flow is adapted to be routed according to any one out of: via a cellular radio network, via a Wireless Local Area Network, WLAN, and via both the cellular radio network and the WLAN 102. The base station is configured to: Obtain from a communication entity, an indication about a WLAN mobility event, and control the data flow based on the obtained indication.

According to a fourth aspect of embodiments herein, the object is achieved by a communication entity for assisting a base station in controlling a data flow related to a user equipment, UE. The data flow is routed according to any one out of: Via a cellular radio network, via a Wireless Local Area Network, WLAN, and via both the cellular radio network and the WLAN. The communication entity is configured to: Estimate a WLAN mobility event, and assist the base station in controlling the data flow by sending an indication about the WLAN mobility event to the base station.

Since the base station has obtained from a communication entity an indication about the WLAN mobility event, the base station can control the data flow based on the obtained indication during the WLAN mobility event. This results in an improved way of integrating communications networks such as a cellular networks and a WLAN.

An advantage with embodiments herein is that efficient base station flow control for cellular network WLAN aggregation is enabled.

DETAILED DESCRIPION

As part of developing embodiments herein, a problem will first be identified and shortly discussed. As mentioned above, it is currently discussed better ways to integrate cellular systems such as LTE and WLAN, in particular for operator-deployed WLANs, so that throughput provided by the individual systems can be aggregated by a UE.

For this purpose, it is currently discussed how to standardize LTE-WLAN

aggregation based on a protocol architecture similar to the split bearer architecture in LTE Dual Connectivity. Thereby, throughput from both LTE and WLAN may be aggregated for a single traffic flow mapped to a split bearer. A potential solution for LTE WLAN aggregation has been discussed, which is shown in Figure 1.

Figure 1 shows an example of a potential LTE-WLAN aggregation architecture based on split bearer architecture.

As can be seen from Figure 1 , control signaling, e.g. received via a Core Network (CN) on S1 -MME, or Radio Resource Control (RRC) signaling is conveyed to the UE via LTE. An eNB may use the S1 -MME interface with the Mobility Management Entity (MME) for control plane traffic. User plane data is received from the CN in the eNB via S1 -U interface. The control plane carries control information, also known as signalling. The user plane carries the user's traffic, such as Internet Protocol (IP) packets. The term base station and eNB is used interchangeably in this document. The user plane data may be split at the Packet Data Convergence Protocol (PDCP) layer among LTE link to the UE such as Radio Link Control (RLC), LTE- Medium Access Control (MAC), LTE- Physical Layer (PHY), and WLAN link to the UE such as IEEE 802.1 1 logical link control (LLC), MAC, and PHY. IEEE 802.1 1 is a set of MAC and PHY specifications for implementing WLAN computer communication e.g. in the 900 MHz and 2.4, 3.6, 5, and 60 GHz frequency bands. To send PDCP Protocol Data Units (PDUs) via the WLAN link, data may need to be adapted. E.g. an additional header identifying the logical channel the PDCP PDU belongs to, may be added to the PDU. The adaptation layer may reside as shown in Figure 1 in the eNB, or also in a WLAN node. Non-access stratum (NAS) describes functions in the LTE wireless telecom protocol stack between the CN and the UE. RRC protocol layer exists in a UE and an eNB, it is part of LTE air interface control plane.

Furthermore, termination of the WLAN protocol may be implemented in a different node, e.g. non-collocated node from the eNB, which node is denoted WLAN Termination (WT) in Figure 1 . The WT is a logical node, which may implement the functionality of one or several WLAN Access Points (APs), and/or WLAN Access Controllers (ACs).

Alternatively, a WT may be co-located with the eNB. An interface between eNB and WLAN termination may be defined, which is denotes as Xw in Figure 1 . This interface may be used to exchange control plane signaling messages, as well as to convey user plane data and flow control feedback for the user plane data. The interface Xw between eNB and WLAN termination is among others discussed in in another Rel-13 study item entitled Multi-RAT Joint Coordination, where it is used for enhancing e.g. traffic offloading decisions from LTE to WLAN. The interface Xw may potentially be reused and extended to cover also the described use cases for LTE WLAN aggregation.

Also reporting of WLAN measurements by the UE in LTE to the eNB may be possible. In this way the eNB may be informed e.g. about signal strengths of WLAN links which the UE measures. This information may be the basis for the eNB to trigger setup, termination or change of the LTE WLAN aggregation. It may also be used by the eNB to reconfigure the UE to trigger certain WLAN Mobility events, e.g. to change the serving AP.

In typical WLAN networks, working standalone, i.e. without LTE aggregation, the mobility is controlled by the UEs which are called Stations (STAs) in context of WLAN. The STAs determine the best AP to connect to and send an Association Request. The request may be granted or denied. Before sending the request, the STA has read a beacon sent by the AP and received system information for that AP to learn whether it may even send the request. The AP may also control the STAs by sending request to make a handover to another AP.

WLAN mobility may be optimized with proprietary methods, e.g. WLAN mobility may be more seamless in terms of shorter data interruption or delays e.g. between APs that belong to the same so called mobility domain. A mobility domain may be e.g. a list of APs, or all APs belonging to the same AC. A mobility domain may include multiple ACs and thus all APs controlled by the ACs. A UE/STA is able to transfer AP more seamlessly within a mobility domain.

Consider a case where LTE-WLAN aggregation has been configured to a WLAN termination point which is a logical node thus it may be associated with a single access point (AP) or an access controller (AC) that controls multiple APs. A WT may also be associated with an AC controlling other ACs. When the AP for the STA changes in WLAN, i.e. WLAN mobility, WLAN handover, there will be interruption in data transferring. It is WLAN network implementation that specifies how data is handled in case of AP change, however interruption in data flow to UE happens during AP change. Depending on whether new and old AP belongs to different mobility domains within the WT, or to the same or different WT, data interruption may take certain time. In case the WLAN mobility is not fully eNB controlled, it is unclear how the data interruption may be mitigated in this situation.

To give a base station such as an eNB control of WLAN mobility in order to handle flow control and delivery of data to a UE efficiently according to embodiments herein, the base station such as the eNB gets to know, preferably prior to handover about the coming WLAN mobility event. In this way, data interruption and delivery delays may be avoided during WLAN mobility as data may be routed to the UE using the LTE link while WLAN link has an interruption.

Embodiments herein relate to flow control during WLAN AP change with LTE-WLAN aggregation. The architecture of Figure 1 may be used to implement embodiments herein.

Figure 2 depicts an example of a communications network 100 in which embodiments herein may be implemented.

The communications network 100 comprises a cellular radio network 101 . The cellular radio network 101 is a wireless communication network or cellular

communications network such as an LTE, WCDMA, GSM network, any 3GPP cellular network, Wimax, or any cellular network or system.

The communications network 100 further comprises a WLAN 102. The WLAN 102 may e.g. be referred to as a WiFi network. One or more base stations operate in the cellular radio network 101 whereof one, a base station 110 is depicted in Figure 2. The base station 1 10 may e.g. be a radio base station, for example an eNB, an eNodeB, or an Home Node B, an Home eNode B or any other network node capable to serve a user equipment or a machine type communication device in a cellular radio network.

Two or more APs operate in the WLAN 102 whereof two, a first AP 11 l and a second AP 112 are depicted in Figure 2.

Further, one or more UEs operate in the communications network 100 whereof one, a UE 120 is depicted in Figure 2. The UE 120 is a communication entity that e.g. may be a user equipment, a mobile terminal or a wireless terminal, a mobile phone, a computer such as e.g. a laptop, a Personal Digital Assistants (PDAs) or a tablet computer, sometimes referred to as a surf plate, with wireless capability, or any other radio network units capable to communicate over a radio link in a wireless communications network. 5 Please note the term user equipment used in this document also covers other wireless devices such as Machine to machine (M2M) devices, even though they do not have any user.

Yet further, a WLAN Termination (WT) node 130 operates in the communications network 100. Also the WT node 130 is referred to as a communication entity. The WT 10 node 130 may e.g. be co-located with any one out of the base station 1 10, the first AP 1 1 1 , the second AP 1 12, and a WLAN Access Controller (AC).

A communication entity 140 operates in the communications network 100. The communication entity 140 may be represented by any one or more out of a

15 communication node such as e.g. the WT node 130 and a wireless communication

network node such as e.g. the UE 120.

A data flow may be routed via the cellular radio network 101 such as e.g. LTE, via a WLAN 102 or via both the cellular radio network 101 such as e.g. LTE, and the WLAN 20 102. This means that the WLAN 102 may be aggregated to the cellular network 101 .

In order to have an efficient flow control also in this case of WLAN based mobility according to embodiments herein, the following example methods may be provided:

The communication entity such as e.g. the WT node 130 or the UE 120 notifies the

25 base station 1 10 about an upcoming WLAN mobility event. The upcoming WLAN mobility event may e.g. be a change from the first AP 1 1 1 of the WLAN 102 to the second AP 1 12 of the WLAN 102 for the UE 120, and/or an interruption that is coming. In other terms an upcoming WLAN mobility event may e.g. be a change from a source AP, i.e. first AP 1 1 1 , to a target AP, i.e. second AP 1 12 for the UE 120.

30 When the base station 1 10 gets this indication a priori, it may route data such as PDCP data via LTE while there is an interruption on the WLAN side. The signalling may also include estimated time to the interruption and estimated duration of the interruption. The estimated duration for the interruption may for example be estimated by the time a WLAN authentication method typically takes.

35 Example of embodiments of a method performed by the base station 1 10 for controlling a data flow related to the UE 120 will now be described with reference to

Figure 3. The data flow is routed according to any one out of: via a cellular radio network 5 101 , via a Wireless Local Area Network, WLAN, 102, and via both the cellular radio network 101 , and the WLAN 102. This means that in some example scenarios the WLAN 102 may be aggregated to the cellular network 101 , i.e. that the data flow such as user plane data can be routed via both cellular radio network and WLAN to the UE 120 and furthermore that due to a joint control, a switch between routing data via either cellular 10 radio network, WLAN, or both can be issued at any time during the aggregation.

The method may comprise the following actions, which actions may be taken in any suitable order.

Action 301

15 To give the base station 1 10 control of WLAN mobility in order to handle the data flow control and delivery of data to the UE 120 efficiently according to embodiments herein, the base station 1 10 requires to know, preferably prior to a handover about the coming WLAN mobility event. Thus according to embodiments herein, the base station 1 10 obtains from the communication entity 120, 130, 140, an indication about a WLAN

20 mobility event.

The indication about the WLAN mobility event may be obtained explicitly or implicitly from the communication entity 120, 130, 140. This will be described more in detail below.

The WLAN mobility event may relate to any one or more out of:

- An upcoming WLAN mobility event.

25 - When performing WLAN mobility event, and.

- When interruption according to a WLAN mobility event has happened.

In some embodiments WLAN mobility event relates to a handover of the UE 120 from the first AP 1 1 1 to the second AP 1 12, i.e. an AP change. Thus the WLAN mobility event may comprise a change from the first, AP 1 1 1 of the WLAN 102 to the second AP 30 1 12 of the WLAN 102 for the UE 120. The indication about the WLAN mobility event may relate to an interruption of the data routed via the WLAN 102.

The indication about the WLAN mobility event may further comprise any one or more out of: estimated time to the interruption related to the change to the second AP 1 12, and estimated duration of the interruption related to the change to the second AP 35 1 12. Based on this the base station 1 10 may change the routing of the data flow for this time duration, and e.g. change back to a previous routing configuration afterwards, optimizing the overall throughput of the data flow.

In some embodiments the communication entity 140, 130 is represented by a WT node 130. In these embodiments the indication about the WLAN mobility event may be obtained from the WT node 130 according to any one out of:

- Implicitly, by obtaining flow control feedback message elements for a Flow Control (FC) protocol between the base station 1 10 and the WT node 130.

- Explicitly, by receiving a signaling message over an application layer protocol between the base station 1 10 and the WT node 130.

In some alternative embodiments, the communication entity 140 is represented by the UE 120. In these embodiments the indication about the WLAN mobility event is obtained from the UE 120 according to any one out of:

- Implicitly, by obtaining a measurement report, based on which, the base station 1 10 implicitly deduces that the UE 120 will change WLAN AP, and

- Explicitly, by receiving the indication in a measurement report, and

- Explicitly, by receiving the indication in a separate message.

Action 302

The base station 1 10 controls the data flow based on the obtained indication. The controlling of the data flow may comprise controlling the routing of the data flow.

Based on the received indication, the base station 1 10 may control the data flow by deciding to route the data flow via the cellular radio network 101 such as e.g. LTE, via the WLAN 102, or via both the cellular radio network 101 such as e.g. LTE, and the WLAN 102. In this way, data interruption and delivery delays may be avoided during WLAN mobility as data may e.g. be routed to the UE using the LTE link while WLAN link has an interruption.

In some embodiments, the indication about the WLAN mobility event comprises an indication that no more data shall be forwarded to a WT node 130 of the WLAN 102 and in some embodiments e.g. when the indication is received when the WLAN mobility event already has started, an indication of packets of the data flow that are lost. E.g. depending on an interruption of the data routed via the WLAN 102.

Action 303

In some embodiments, the base station 1 10 controls the data flow by routing the data related to the UE 120 only via the cellular radio network 101 . However, in some further embodiments, the base station 1 10 may route the data flow only via the WLAN 102, or via both the cellular radio network 101 such as e.g. LTE, and the WLAN 102.

To avoid the data interruption at the WLAN mobility event, the base station 1 10 would control the data flow by routing the data to the UE 120 only via the cellular network. However, for example in cases where the cellular radio network 101 is under high load, it may be beneficial to route the data flow via WLAN despite the indicated WLAN mobility event. Furthermore, in an intermediate case, for example at medium cellular network load, and when only a short data interruption at the WLAN mobility event is expected, it may be beneficial to route the data flow via both cellular radio network 101 and the WLAN 102.

Action 304

In some embodiments wherein the base station 1 10 has routed the data related to the UE 120 only via the cellular radio network 101 , the base station 1 10 may re-route the data related to the UE 120 via the WLAN 102 again, when the first AP 1 1 1 has been changed to the second AP 1 12 for the user equipment UE 120.

Example of similar embodiments of a method performed by the base station 1 10, for handling routing of a data flow related to a user equipment, UE, 120, will now be described with reference to Figure 4 and 7. The data flow may be routed via a cellular radio network 101 such as e.g. LTE, via a WLAN 102 or via both the cellular radio network 101 such as e.g. LTE, and the WLAN 102. This means that the WLAN 102 may be aggregated to the cellular network 101 .

The cellular radio network 101 is a wireless communication network or cellular communications network such as an LTE, WCDMA, GSM network, any 3GPP cellular network, Wimax, or any cellular network or system.

The base station 1 10 may be a radio base station, for example an eNB, an eNodeB, or an Home Node B, an Home eNode B or any other network node capable to serve a user equipment or a machine type communication device in a cellular radio network.

The UE 120 may e.g. be a user equipment, a mobile terminal or a wireless terminal, a mobile phone, a computer such as e.g. a laptop, a Personal Digital Assistants PDAs or a tablet computer, sometimes referred to as a surf plate, with wireless capability, or any other radio network units capable to communicate over a radio link in a wireless communications network. Please note the term user equipment used in this document also covers other wireless devices such as Machine to machine M2M devices, even though they do not have any user.

The WLAN 102 may e.g. be a WiFi network.

Action 401

The base station 1 10 may e.g. explicitly or implicitly, obtain from a communication entity 120, 130 such as e.g. a WT node 130 or a UE 120, an indication about an upcoming WLAN mobility event such as a change from a first AP 1 1 1 of the WLAN 102 to a second AP 1 12 of the WLAN 102 for the UE 120.

The indication about the WLAN mobility event may relates to an interruption of the data routed via the WLAN 102.

The indication about the WLAN mobility event may further comprise any one or more out of: estimated time to the interruption related to the change to the second AP 1 12, and estimated duration of the interruption related to the change to the second AP 1 12.

The communication entity may be represented by any one or more out of a communication node or wireless communication network node.

The communication entity may be represented by any one out of: a WLAN

Termination, WT, node 130, which WT node 130 e.g. may be co-located with any one out of the base station 1 10, the first AP 1 1 1 , the second AP 1 12, a WLAN Access Controller, AC.

The communication entity may further be represented by the UE 120.

The base station or an obtaining module 710 therein may be configured to perform this action.

Action 402

Based on the obtained indication, the base station 1 10 may route the data related to the UE 120 only via the cellular radio network 101 such as e.g. LTE. The base station or a routing module 720 therein may be configured to perform this action.

Action 403

When the first AP 1 1 1 has been changed to the second AP 1 12 for the UE 120, the base station 1 10 may re-route the data or part of the data related to the UE 120 via the WLAN 102 again. The base station or the routing module 720 therein may be configured to perform this action.

Example of embodiments of a method performed by a communication entity 120,

130, 140, for assisting the base station 1 10 in controlling a data flow related to the UE 120, will now be described with reference to Figure 5. The data flow is routed according to any one out of: via a cellular radio network 101 , via a Wireless Local Area Network, WLAN, 102, and via both the cellular radio network 101 and the WLAN. As mentioned above, this means that the WLAN 102 may be aggregated to the cellular network 101 .

Action 501

The communication entity 120, 130 estimates a WLAN mobility event. How this is done will be described more in detail below.

The WLAN mobility event may relate to any one or more out of: An upcoming WLAN mobility event, when performing WLAN mobility event, and when interruption according to a WLAN mobility event has happened.

The WLAN mobility event may comprise a change from a first, AP 1 1 1 of the WLAN

102 to a second AP 1 12 of the WLAN 102 for the UE 120. This may be referred to as an

AP change.

Action 502

The communication entity 120, 130 assists the base station 1 10 in controlling the data flow by sending an indication about the WLAN mobility event to the base station 1 10.

Assisting the base station 1 10 in controlling the data flow may comprise assisting the base station 1 10 in controlling the routing of the data flow.

In some embodiments, the indication about the WLAN mobility event may comprise an indication that no more data shall be forwarded to the WT node 130 of the WLAN 102 and an indication of packets of the data flow that are lost.

In some embodiments, the indication about the WLAN mobility event further comprises any one or more out of: Estimated time to the interruption related to the change to the second AP 1 12, and estimated duration of the interruption related to the change to the second AP 1 12.

The indication about the WLAN mobility event may be sent explicitly or implicitly to the base station 1 10.

In some embodiments the communication entity 140 is represented by a WT node

130. In these embodiments, the indication about the WLAN mobility event may be sent to the base station 1 10 according to any one out of: Implicitly, by sending flow control feedback message elements for an FC protocol to the base station 1 10, and explicitly, by sending a signalling message over an application layer protocol to the base station 1 10.

In some alternative embodiments the communication entity 140 is represented by the UE 120. In these embodiments, the indication about the WLAN mobility event may be sent to the base station 1 10 from the UE 120 according to any one out of:

Implicitly, by sending a measurement report, based on which, the base station 1 10 implicitly deduces that the UE 120 will change WLAN AP, explicitly, by sending the indication in a measurement report, and explicitly, by sending the indication in a separate message.

In some embodiments the communication entity 140 is represented by the WT node 130. The WT node 130 may be co-located with any one out of: The base station 1 10, the first AP 1 1 1 , the second AP 1 12, a WLAN Access Controller, AC.

Example of similar embodiments of a method performed by a communication entity 120, 130 such as the WT node 130 or the UE 120, for assisting the base station 1 10 in routing a data flow related to a UE 120, will now be described with reference to Figure 6 and 8. The data flow may be routed via a cellular radio network 101 such as e.g. LTE, via a WLAN 102 or via both the cellular radio network 101 such as e.g. LTE, and the WLAN 102. This means that the WLAN 102 may be aggregated to the cellular network 101 .

Action 601

The communication entity 120, 130 such as the WT node 130 or the UE 120 may estimate an upcoming WLAN mobility event such as a change from a first AP 1 1 1 of the WLAN 102 to a second AP 1 12 of the WLAN 102 for the UE 120. The communication entity 120, 130 such as the WT node 130 or the UE 120, or an estimating module 810 therein may be configured to perform this action.

Action 602

5 The communication entity 120, 130 such as the WT node 130 or the UE 120 may send, e.g. explicitly or implicitly, an indication about the upcoming AP change to the base station 1 10. The indication may enable the base station 1 10 to route the data related to the UE 120 only via the cellular radio network 101 such as e.g. LTE.

The indication about the AP change may relate to an interruption of the data routed 10 via the WLAN 102.

The indication about the AP change may further comprise any one or more out of: estimated time to the interruption related to the change to the second AP 1 12, and estimated duration of the interruption related to the change to the second AP 1 12.

The communication entity may be represented by a WLAN Termination, WT, node 15 130, which WT node 130 e.g. may be co-located with any one out of the base station 1 10, the first AP 1 1 1 , the second AP 1 12, a WLAN Access Controller, AC.

The communication entity may further be represented by the UE 120

The communication entity 120, 130 such as the WT node 130 or the UE 120, or a sending module 820 therein may be configured to perform this action.

20

The embodiments above will now be described more in detail and exemplified. This text below is applicable to any suitable embodiment described above.

25 In the following two example, methods are describe by which the eNB such as the base station 1 10 may be informed about an upcoming WLAN mobility event potentially associated with a data interruption if not properly dealt with. In the subsections it is further described how the eNB such as the base station 1 10 may mitigate the potential data interruption based on the obtained information.

30

The eNB such as the base station 110 informed by the WT such as the WT node 130

In some embodiments, the WT such as the WT node 130 informs the eNB, such as 35 the base station 1 10, of a change of WLAN AP for a given UE such as the UE 120. The change of WLAN AP may e.g. relate to an upcoming change or an ongoing change. The change of WLAN AP may e.g. be from the first AP1 1 1 also referred to as a source AP, to the second AP 1 12 also referred to as the target AP. The WT such as e.g. the WT node 130 to which the source AP belongs may estimate the upcoming mobility event. The WT may inform the eNB such as the base station 1 10 in different ways, e.g.:

Inband

The base station 1 10 may be informed, such as receiving the indication about the WLAN mobility event from the WT node 130 inband, i.e. no explicit signaling is needed meaning that the indication is provided within existing signaling. In this case the WT node 130 may reuse flow control feedback message elements for a Flow Control (FC) protocol between the eNB such as the base station 1 10 and WT node 130. E.g. by

- If FC is window based, feedback information may include following information:

Advertising desired buffer size as 0, that is no data packets in the buffer. Information which Xw-U sequence numbers are lost, that is which data packets that are lost.

Information which PDCP PDUs have been received by the UE 120, that is which data packets that are received by the UE 120.

- Else if FC is rate based, feedback information may include following information:

Indicate rate = 0 Mbps.

Information which Xw-U sequence numbers are lost, that is which data packets that are lost.

Information which PDCP PDUs have been received by the UE, that is which data packets that are received by the UE 120.

Based on receiving such feedback, the eNB such as the base station 1 10 would stop forwarding data to the WT node 130 for transmission to the UE 120 and instead transmit the data to the UE 120 itself. The eNB such as the base station 1 10 may retransmit PDCP PDUs which have not been acknowledged yet or have been reported to be lost. Determination of which PDUs to retransmit may be done based on flow control information and received Xw-U and PDCP sequence numbers.

Outband

The base station 1 10 may be informed, such as receive the indication about the WLAN mobility event from the WT node 130 outband, i.e. by explicit signaling meaning that new signaling is defined for this purpose outside of existing signaling. This means typically by sending a signaling message from the WT node 130 to the eNB such as the base station 1 10 over an application layer protocol, e.g. defined for Xw. E.g. by:

- Sending the same information as for the flow control above, i.e. indicating that no more data shall be forwarded to the WT node 130 as well as indication of packets that are lost.

- Informing about time to interruption and duration of interruption. The duration of the interruption depends e.g. on used authentication method of the UE 120. The duration depends also on type of WLAN mobility, e.g. mobility between APs such as the first AP1 1 1 and the second AP1 12, belonging to the same AC, or to the same WT, or not to the same WT, or whether the APs belong to the same mobility domain within an AP, a WT, or not.

- Based on that information the eNB such as the base station 1 10 may stop forwarding packets immediately or after a certain fraction of the indicated "time to interruption". The eNB such as the base station 1 10 may suspend the data forwarding only for the indicated "duration of interruption" and resume data forwarding afterwards. In addition, the eNB such as the base station 1 10 may start retransmission of the PDCP PDUs as explained above.

Furthermore, the WT may indicate in case of inter-WT mobility also the new WT to which the UE 120 will connect to. In this case the eNB such as the base station 1 10 may setup a new Xw interface instance to the new WT. Temporarily the eNB such as the base station 1 10 may maintain both Xw interfaces for the UE 120. The indicated "duration of interruption" may be used by the eNB such as the base station 1 10 to determine for how long data shall be exclusively routed to the UE 120 via the eNB-UE LTE connection itself. After "time to interruption" + "duration of interruption" the eNB such as the base station 1 10 may start forwarding data on the new Xw interface to the new WT and stop forwarding data to the old WT. At that time maintaining the old Xw to the old WT may be stopped. In addition, the eNB such as the base station 1 10 may start retransmission of the PDCP PDUs as towards new WT.

The eNB such as the base station 110 informed by the UE 120 The UE 120 informs eNB such as the base station 1 10, such as sends the indication about the WLAN mobility event. E.g. to indicate that it is going to happen and possibly that data interruption is coming and optionally about the new AP such as the second AP 1 12.

The information such as the indication about the WLAN mobility event may be included in a Measurement report, based on which the eNB such as the base station 1 10 implicitly deduces that the UE 120 will change WLAN AP. Based on comparing WLAN measurement values, e.g. Received Signal Strength Indicator (RSSI), with configured thresholds for UE based WLAN mobility, the eNB such as the base station 1 10 may further deduce when the WLAN mobility is going to happen, e.g. by considering certain UE trajectory and speed.

• Explicit indication from UE 120 e.g. before the UE 120 will change the WLAN AP. This may be included in a measurement report or in a separate message, for instance a RRC message. The message may indicate:

- Change of WLAN AP or that the UE 120 has lost connection with WLAN AP.

- That the change of a WLAN AP is about to happen, e.g. the explicit indication from the UE 120 is triggering a certain preconfigured time before the AP change is done.

Another way of achieving this behavior would be to define that the WLAN mobility event has a certain time to trigger, referred to as timeToTrigger, after mobility conditions and/or thresholds are met. The indication to the eNB such as the base station 1 10 would however happen already earlier, e.g. a certain time to report, referred to as timeToReport, after the conditions are met. TimeToTrigger and timeToReport may be preconfigured.

- Handover type, e.g. within WLAN mobility area or between WLAN mobility area. See also explanations for interruption duration in previous subsection.

- When, i.e. in which time, the WLAN mobility event is going to happen.

- The estimated time the WLAN mobility and associated data interruption would take.

For the case where the UE 120 informs eNB such as the base station 1 10 of an upcoming WLAN AP change, the UE may include a PDCP status report to inform the eNB such as the base station 1 10 of the PDCP receiver status. The UE 120 may also be specified to always report the PDCP receiver status when performing the WLAN mobility event such as a WLAN AP/WT change or when interruption has happened due to any reason, or periodically. Thus also a PDCP status report may be triggered in case the information of the interruption is received from the WT node 130. The PDCP status report helps the eNB such as the base station 1 10 to understand which PDCP PDUs had already been received by the UE 120 and this way data forwarding to the new WT or new AP may be done more selectivity, i.e. already received PDUs may be excluded from the forwarding and later retransmission, which is more efficient.

Based on the received information from the UE 120, the eNB such as the base station 1 10 may react similarly as described for the information obtained from the WT (see previous subsection).

Optionally, the UE 120 may also inform Basic Service Set Identifier (BSSID) or other details of the target AP if seen needed. This may be done even if the indication of HO is not included with the measurement reports which would likely include these by default.

To perform the method actions for controlling a data flow related to the UE 120, base station 1 10 may comprise the following arrangement depicted in Figure 7. As mentioned above the data flow is adapted to be routed according to any one out of: via a cellular radio network 101 , via a Wireless Local Area Network, WLAN, 102, and via both the cellular radio network 101 and the WLAN 102.

The base station 1 10 is configured to, e.g. by means of an obtaining module 710 configured to, obtain from a communication entity 120, 130, 140, an indication about a WLAN mobility event.

The WLAN mobility event may be adapted to relate to any one or more out of: An upcoming WLAN mobility event, when performing WLAN mobility event, and when interruption according to a WLAN mobility event has happened.

In some embodiments, the indication about the WLAN mobility event is adapted to comprise an indication that no more data shall be forwarded to the WT node 130 of the WLAN 102, and an indication of packets of the data flow that are lost. The indication about the WLAN mobility event may be adapted to comprise an interruption of the data routed via the WLAN 102.

The indication about the WLAN mobility event may further be adapted to comprise any one or more out of: Estimated time to the interruption related to the change to the second AP 1 12, and estimated duration of the interruption related to the change to the second AP 1 12.

In some embodiments, the communication entity 140 is configured to be

represented by the WT node 130. In these embodiments, the indication about the WLAN mobility event may be adapted to be obtained from the WT node 130 according to any one out of:

Implicitly, by obtaining flow control feedback message elements for a FC protocol between the base station 1 10 and the WT node 130.

Explicitly, by receiving a signalling message over an application layer protocol between the base station 1 10 and the WT node 130.

The communication entity 140 is in some embodiments, adapted to be represented by the UE 120. In these embodiments, the indication about the WLAN mobility event is adapted to be obtained from the UE 120 according to any one out of:

Implicitly, by obtaining a measurement report, based on which, the base station 1 10 implicitly deduces that the UE 120 will change WLAN AP, explicitly, by receiving the indication in a measurement report, and explicitly, by receiving the indication in a separate message.

The base station 1 10 is further configured to, e.g. by means of a processor 720 configured to, control the data flow based on the obtained indication.

The base station 1 10 being configured to control the data flow may comprise, the base station 1 10 being configured to, e.g. by means of a routing module 730 configured to, route the data related to the UE 120 only via the cellular radio network 101 .

The base station 1 10 may further be configured to control the data flow by, e.g. by means of the routing module 730 configured to, control the routing of the data flow.

In some embodiments, the WLAN mobility event is adapted to comprise a change from the first AP 1 1 1 of the WLAN 102 to a second AP 1 12 of the WLAN 102 for the UE The indication about the WLAN mobility event may be adapted to be obtained explicitly or implicitly from the communication entity 120, 130, 140.

The base station 1 10 further being configured to,, e.g. by means of the routing module 730 configured to, when the first AP 1 1 1 has been changed to the second AP 1 12 for the UE 120, re-route the data related to the UE 120 via the WLAN 102 again.

In some embodiments, a computer program comprises instructions, which when executed by the at least one processor 720, cause the at least one processor 720 to perform actions according to any of the Actions 301 -304, and 401 -403.

In some embodiments, a carrier comprises the computer program, wherein the carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer- readable storage medium.

To perform the method actions for assisting the base station 1 10 in controlling a data flow related to the UE 120, the communication entity 120, 130, 140 may comprise the following arrangement depicted in Figure 8. As mentioned above, the data flow is routed according to any one out of: via a cellular radio network 101 , via a Wireless Local Area Network, WLAN, 102, and via both the cellular radio network 101 and the WLAN 102. The communication entity 120, 130, 140 is configured to, e.g. by means of an estimating module 810 configured to, estimate a WLAN mobility event.

The WLAN mobility event may be adapted to comprise a change from the first AP

1 1 1 of the WLAN 102 to a second AP 1 12 of the WLAN 102 for the UE 120. The communication entity 120, 130, 140 is configured to, e.g. by means of a sending module 820 configured to, assist the base station 1 10 in controlling the data flow by sending an indication about the WLAN mobility event to the base station 1 10.

The communication entity 120, 130, 140 being configured to assisting the base station 1 10 in controlling the data flow may comprise the communication entity 120, 130, 140 being configured to assisting the base station 1 10 in controlling the routing of the data flow.

The indication about the WLAN mobility event may be adapted to comprise an indication that no more data shall be forwarded to the WT node 130 of the WLAN 102 and an indication of packets of the data flow that are lost.

In some embodiments, the indication about the WLAN mobility event is adapted to relate to an interruption of the data routed via the WLAN 102.

In some embodiments, the communication entity 120, 130, 140 further is configured to send the indication about the WLAN mobility event explicitly or implicitly to the base station 1 10.

In some embodiments, the communication entity 140 is adapted to be represented by the WT node 130. In these embodiments, the communication entity 120, 130, 140 may further be configured to send the indication about the WLAN mobility event to the base station 1 10 according to any one out of: Implicitly, by sending flow control feedback message elements for an FC protocol to the base station 1 10, and explicitly, by sending a signalling message over an application layer protocol to the base station 1 10.

In the embodiments where the communication entity 140 is adapted to be represented by the WT node 130, the WT node 130 may be co-located with any one out of: the base station 1 10, the first AP 1 1 1 , the second AP 1 12, a WLAN Access Controller, (AC).

In some embodiments, the communication entity 140 is adapted to be represented by the UE 120. In these embodiments, the communication entity 120, 140 further is configured to send the indication about the WLAN mobility event to the base station 1 10 from the UE 120 according to any one out of: Implicitly, by sending a measurement report, based on which, the base station 1 10 implicitly deduces that the UE 120 will change WLAN AP, explicitly, by sending the indication in a measurement report, and explicitly, by sending the indication in a separate message.

5

In some embodiments, a computer program comprises instructions, which when executed by the at least one processor 830, cause the at least one processor 830 to perform actions according to any of the Actions 501 -502 and 601 -602.

10 In some embodiments, a carrier comprises the computer program, wherein the

carrier is one of an electronic signal, an optical signal, an electromagnetic signal, a magnetic signal, an electric signal, a radio signal, a microwave signal, or a computer- readable storage medium.

15

The embodiments herein comprising the process of controlling a data flow related to a UE 120 and assisting the base station 1 10 in controlling a data flow related to a UE 120, may be implemented through one or more processors, such as the processor 720 in the base station 1 10 depicted in Figure 7 and a processor 830 in the communication entity

20 120, 130 such as WT node 130 or UE 120 depicted in Figure 8, together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier carrying computer program code for performing the embodiments herein when being loaded into the base station 1 10 and/or the

25 communication entity 120, 130 140 such as the WT node 130 or the UE 120. One such carrier may be in the form of a CD ROM disc. It is however feasible with other data carriers such as a memory stick. The computer program code may furthermore be provided as pure program code on a server and downloaded to the base station 1 10 and/or the communication entity 120, 130 140 such as WT node 130 or UE 120.

30

The base station 1 10 and/or the communication entity 120, 130 such as WT node 130 or UE 120 may further comprise a respective memory comprising one or more memory units, such as the memory 740 in Figure 7, and the memory 840 in Figure 8. The respective memory 740 and memory 840 each comprises instructions executable by 35 the respective processor. The respective memory 740 and memory 840 are arranged to be used to store e.g. data, configurations, and applications to perform the methods herein when being executed in base station 1 10 and/or the communication entity 120, 130 such as WT node 130 or UE 120.

Those skilled in the art will also appreciate that the modules in the base station 1 10 and/or the communication entity 120, 130 such as WT node 130 or UE 120, described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in the respective memory 740 and memory 840, that when executed by the one or more processors such as the processor 720 and the processor 830 as described above. One or more of these processors, as well as the other digital hardware, may be included in a single Application- Specific Integrated Circuitry (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system-on-a-chip (SoC).

The base station 1 10 may further comprise a sending/receiving module 750. The communication entity 120, 130, 140 may further comprise a sending/receiving module 850. The sending/receiving modules may be used for communication.

When using the word "comprise" or "comprising" it shall be interpreted as non- limiting, i.e. meaning "consist at least of".

The embodiments herein are not limited to the above described preferred embodiments. Various alternatives, modifications and equivalents may be used.

Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.

Claims

1 . A method performed by a base station (1 10), for controlling a data flow related to a user equipment, UE, (120), which data flow is routed according to any one out of: via a cellular radio network (101 ), via a Wireless Local Area Network, WLAN, (102), and via both the cellular radio network (101 ), and the WLAN (102), the method comprising:

obtaining (301 ) from a communication entity (120, 130, 140) an indication about a WLAN mobility event,

controlling (302) the data flow based on the obtained indication.

The method according to claim 1 , wherein controlling (302) the data flow comprises:

routing (303) the data related to the UE (120) only via the cellular radio network (101 ).

The method according to any of the claim 1 -2, wherein the WLAN mobility event relates to any one or more out of:

an upcoming WLAN mobility event,

when performing WLAN mobility event, and

when interruption according to a WLAN mobility event has happened.

The method according to any of the claim 1 -3, wherein controlling (302) the data flow comprises, controlling (302) the routing of the data flow.

The method according to any of the claim 1 -4, wherein the indication about the WLAN mobility event comprises an indication that no more data shall be forwarded to a WLAN Termination, WT, node (130) of the WLAN (102) and an indication of packets of the data flow that are lost.

The method according to any of the claim 1 -5, wherein the WLAN mobility event comprises a change from a first, Access Point, AP, (1 1 1 ) of the WLAN (102) to a second AP (1 12) of the WLAN (102) for the UE (120).

7. The method according to any of the claims 1 -6, wherein the indication about the WLAN mobility event relates to an interruption of the data routed via the WLAN (102).

The method according to claim 7, wherein the indication about the WLAN mobility event further comprises any one or more out of: estimated time to the interruption related to the change to the second AP (1 12), and estimated duration of the interruption related to the change to the second AP (1 12).

The method according to any of the claim 1 -8, wherein the indication about the WLAN mobility event is obtained explicitly or implicitly from the communication entity (120, 130, 140).

10. The method according to any of the claim 1 -9, wherein the communication entity (130, 140) is represented by a WLAN Termination, WT, node (130), wherein the indication about the WLAN mobility event is obtained from the WT node (130) according to any one out of:

implicitly, by obtaining flow control feedback message elements for a Flow Control (FC) protocol between the base station (1 10) and the WT node (130). explicitly, by receiving a signalling message over an application layer protocol between the base station (1 10) and the WT node (130).

The method according to any of the claims 1 -10, wherein the communication entity (120, 140) is represented by the UE (120), wherein the indication about the WLAN mobility event is obtained from the UE (120) according to any one out of:

implicitly, by obtaining a measurement report, based on which, the base station (1 10) implicitly deduces that the UE (120) will change WLAN AP, and

explicitly, by receiving the indication in a measurement report, and

explicitly, by receiving the indication in a separate message.

The method according to any of the claim 6-1 1 , further comprising

when the first, Access Point, AP, (1 1 1 ) has been changed to the second AP (1 12) for the UE (120), re-routing (304) the data related to the UE (120) via the WLAN (102) again.

13. A method performed by a communication entity (120, 130, 140), for assisting a base station (1 10) in controlling a data flow related to a user equipment, UE, (120), which data flow is routed according to any one out of: via a cellular radio network (101 ), via a Wireless Local Area Network, WLAN, (102), and via both the cellular radio network (101 ) and the WLAN (102), the method comprising:

estimating (501 ) a WLAN mobility event,

assisting the base station (1 10) in controlling the data flow by sending (502), an indication about the WLAN mobility event to the base station (1 10).

14. The method according to claim 13, wherein the WLAN mobility event relates to any one or more out of:

an upcoming WLAN mobility event,

when performing WLAN mobility event, and

when interruption according to a WLAN mobility event has happened.

15. The method according to any of the claim 13-14, wherein assisting the base station (1 10) in controlling the data flow comprises, assisting the base station (1 10) in controlling the routing of the data flow.

16. The method according to any of the claim 13-15, wherein the indication about the WLAN mobility event comprises an indication that no more data shall be forwarded to a WLAN Termination, WT, node (130) of the WLAN (102) and an indication of packets of the data flow that are lost.

17. The method according to any of the claim 13-16, wherein the WLAN mobility event comprises a change from a first, Access Point, AP, (1 1 1 ) of the WLAN (102) to a second AP (1 12) of the WLAN (102) for the UE (120).

18. The method according to any of the claims 13-17, wherein the indication about the WLAN mobility event relates to an interruption of the data routed via the WLAN (102).

19. The method according to claim 18, wherein the indication about the WLAN mobility event further comprises any one or more out of: estimated time to the interruption related to the change to the second AP (1 12), and estimated duration of the interruption related to the change to the second AP (1 12).

20. The method according to any of the claim 13-19, wherein the indication about the WLAN mobility event is sent explicitly or implicitly to the base station (1 10).

21 . The method according to any of the claim 13-20, wherein the communication entity (130, 140) is represented by a WLAN Termination, WT, node (130), wherein the indication about the WLAN mobility event is sent to the base station (1 10) according to any one out of:

implicitly, by sending flow control feedback message elements for a Flow Control (FC) protocol to the base station (1 10), and

explicitly, by sending a signalling message over an application layer protocol to the base station (1 10).

22. The method according to claim 21 , wherein the communication entity (130, 140) is represented by a WLAN Termination, WT, node (130), which WT node (130) is co- located with any one out of: the base station (1 10), a first AP (1 1 1 ), a second AP (1 12), a WLAN Access Controller, AC.

23. The method according to any of the claims 17-22, wherein the communication entity (120, 140) is represented by the UE (120), and wherein the indication about the WLAN mobility event is sent to the base station (1 10) from the UE (120) according to any one out of:

implicitly, by sending a measurement report, based on which, the base station

(1 10) implicitly deduces that the UE (120) will change WLAN AP, and

explicitly, by sending the indication in a measurement report, and

explicitly, by sending the indication in a separate message.

24. A base station (1 10) for controlling a data flow related to a user equipment, UE, (120), which data flow is adapted to be routed according to any one out of: via a cellular radio network (101 ), via a Wireless Local Area Network, WLAN, (102), and via both the cellular radio network (101 ) and the WLAN (102), the base station (1 10) being configured to: obtain from a communication entity (120, 130, 140) an indication about a WLAN mobility event, and

control the data flow based on the obtained indication.

25. The base station (1 10) according to claim 24, wherein the base station (1 10) being configured to control the data flow comprises:

the base station (1 10) being configured to route the data related to the UE (120) only via the cellular radio network (101 ).

26. The base station (1 10) according to any of the claim 24-25, wherein the WLAN mobility event is adapted to relate to any one or more out of:

an upcoming WLAN mobility event,

when performing WLAN mobility event, and

when interruption according to a WLAN mobility event has happened.

27. The base station (1 10) according to any of the claim 24-26, wherein the base

station (1 10) being configured to control the data flow comprises the base station (1 10) being configured to control the routing of the data flow.

28. The base station (1 10) according to any of the claim 24-27, wherein the indication about the WLAN mobility event is adapted to comprise an indication that no more data shall be forwarded to a WLAN Termination, WT, node (130) of the WLAN (102) and an indication of packets of the data flow that are lost.

29. The base station (1 10) according to any of the claim 24-28, wherein the WLAN mobility event is adapted to comprise a change from a first, Access Point, AP, (1 1 1 ) of the WLAN (102) to a second AP (1 12) of the WLAN (102) for the UE (120).

30. The base station (1 10) according to any of the claims 24-29, wherein the indication about the WLAN mobility event is adapted to comprise an interruption of the data routed via the WLAN (102).

31 . The base station (1 10) according to claim 30, wherein the indication about the

WLAN mobility event further is adapted to comprise any one or more out of:

estimated time to the interruption related to the change to the second AP (1 12), and estimated duration of the interruption related to the change to the second AP (1 12).

32. The base station (1 10) according to any of the claim 24-31 , wherein the indication about the WLAN mobility event is adapted to be obtained explicitly or implicitly from the communication entity (120, 130, 140).

33. The base station (1 10) according to any of the claim 24-32, wherein the

communication entity (130, 140) is configured to be represented by a WLAN Termination, WT, node (130), wherein the indication about the WLAN mobility event is adapted to be obtained from the WT node (130) according to any one out of:

implicitly, by obtaining flow control feedback message elements for a Flow Control (FC) protocol between the base station (1 10) and the WT node (130), and explicitly, by receiving a signalling message over an application layer protocol between the base station (1 10) and the WT node (130).

34. The base station (1 10) according to any of the claims 24-33, wherein the

communication entity (120, 140) is adapted to be represented by the UE (120), wherein the indication about the WLAN mobility event is adapted to be obtained from the UE (120) according to any one out of:

explicitly, by receiving the indication in a measurement report, and

explicitly, by receiving the indication in a separate message.

35. The base station (1 10) according to any of the claim 29-34, further being

configured to:

when the first, Access Point, AP, (1 1 1 ) has been changed to the second AP (1 12) for the UE (120), re-route the data related to the UE (120) via the WLAN

(102) again.

36. A communication entity (120, 130, 140) for assisting a base station (1 10) in

controlling a data flow related to a user equipment, UE, (120), which data flow is routed according to any one out of: via a cellular radio network (101 ), via a Wireless Local Area Network, WLAN, (102), and via both the cellular radio network

(101 ) and the WLAN (102), the communication entity (120, 130, 140) being configured to:

estimate a WLAN mobility event, and

assist the base station (1 10) in controlling the data flow by sending an indication about the WLAN mobility event to the base station (1 10).

37. The communication entity (120, 130, 140) according to claim 36, wherein the

WLAN mobility event is adapted to relate to any one or more out of:

an upcoming WLAN mobility event,

when performing WLAN mobility event, and

when interruption according to a WLAN mobility event has happened.

38. The communication entity (120, 130, 140) according to any of the claim 36-38, wherein the communication entity (120, 130, 140) being configured to assisting the base station (1 10) in controlling the data flow comprises the communication entity (120, 130, 140) being configured to assisting the base station (1 10) in controlling the routing of the data flow.

39. The communication entity (120, 130, 140) according to any_of the claim 36-37, wherein the indication about the WLAN mobility event is adapted to comprise an indication that no more data shall be forwarded to a WLAN Termination, WT, node (130) of the WLAN (102) and an indication of packets of the data flow that are lost.

40. The communication entity (120, 130, 140) according to any of the claim 36-39, wherein the WLAN mobility event is adapted to comprises a change from a first, Access Point, AP, (1 1 1 ) of the WLAN (102) to a second AP (1 12) of the WLAN

(102) for the UE (120).

41 . The communication entity (120, 130, 140) according to claim 40, wherein the

indication about the WLAN mobility event is adapted to relate to an interruption of the data routed via the WLAN (102).

42. The communication entity (120, 130, 140) according to any of the claims 40-41 , wherein the indication about the WLAN mobility event further is adapted to comprise any one or more out of: estimated time to the interruption related to the change to the second AP (1 12), and estimated duration of the interruption related to the change to the second AP (1 12).

43. The communication entity (120, 130, 140) according to any of the claim 36-42, wherein the communication entity (120, 130, 140) further is configured to send the indication about the WLAN mobility event explicitly or implicitly to the base station (1 10).

The communication entity (120, 130, 140) according to any of the claim 36-43, wherein the communication entity (140) is adapted to be represented by a WLAN Termination, WT, node (130), wherein the communication entity (120, 130, 140) further is configured to send the indication about the WLAN mobility event to the base station (1 10) according to any one out of:

45. The communication entity (120, 130, 140) according to claim 44, wherein the

communication entity (130, 140) is adapted to be represented by a WLAN

Termination, WT, node (130), which WT node (130) is co-located with any one out of: the base station (1 10), a first AP (1 1 1 ), a second AP (1 12), a WLAN Access Controller, AC.

46. The communication entity (120, 130, 140) according to any of the claims 36-45, wherein the communication entity (120, 140) is adapted to be represented by the UE (120), and wherein the communication entity (120, 140) further is configured to send the indication about the WLAN mobility event to the base station (1 10) from the UE (120) according to any one out of:

implicitly, by sending a measurement report, based on which, the base station (1 10) implicitly deduces that the UE (120) will change WLAN AP, and

explicitly, by sending the indication in a measurement report, and

explicitly, by sending the indication in a separate message.