TECHNICAL FIELD

Embodiments herein relate to a first radio network node, a second radio network node and methods performed therein for communication. Furthermore, a computer program and a computer readable storage medium are also provided herein. In particular, embodiments herein relate to handling communication for a wireless device or a radio network node in a wireless communication network. BACKGROUND

In a typical wireless communication network, wireless devices, also known as wireless communication devices, mobile stations, stations (STA) and/or user equipments (UE), 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 a radio access node e.g., a Wi-Fi access point or a radio base station (RBS), which in some networks may also be denoted, for example, a "NodeB" or "eNodeB". A service area or cell area is a geographical area where radio coverage is provided by the radio network node. The radio network node communicates over an air interface operating on radio frequencies with the wireless device within range of the radio network node.

A Universal Mobile Telecommunications System (UMTS) is a third generation (3G) telecommunication network, which evolved from the second generation (2G) 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 user equipments. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks, 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. This type of connection is sometimes referred to as a backhaul connection. The RNCs and BSCs are typically connected to one or more core networks. Specifications for the Evolved Packet System (EPS), also called a Fourth

Generation (4G) network, have been completed within the 3 ^rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, for example to specify a Fifth Generation (5G) network. 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 variant of a 3GPP radio access network wherein the radio network nodes are directly connected to the EPC core network rather than to RNCs. In general, in E-UTRAN/LTE the functions of an RNC are distributed between the radio network nodes, e.g. eNodeBs in LTE, and the core network. As such, the RAN of an EPS has an essentially "flat" architecture comprising radio network nodes connected directly to one or more core networks, i.e. they are not connected to RNCs. To compensate for that, the E-UTRAN specification defines a direct interface between the radio network nodes, this interface being denoted the X2 interface. EPS is the Evolved 3GPP Packet Switched Domain. Fig. 1 is an overview of the EPC architecture. This architecture is defined in 3GPP TS 23.401 v.13.4.0 wherein definitions of radio network nodes such as a Packet Data Network Gateway (P-GW), a Serving Gateway (S-GW), a Policy and Charging Rules Function (PCRF), a Mobility Management Entity (MME) and also for a wireless or mobile device (denoted as UE) are found. The LTE radio access, E-UTRAN, comprises one or more eNBs. Fig. 2 shows the overall E- UTRAN architecture and is further defined in for example 3GPP TS 36.300 v.13.1.0. The E-UTRAN comprises eNBs, providing a user plane comprising the protocol layers Packet Data Convergence Protocol (PDCP)/Radio Link Control (RLC)/Medium Access Control (MACyPhysical layer (PHY), and a control plane comprising Radio Resource Control (RRC) protocol in addition to the user plane protocols towards the wireless device. The radio network nodes are interconnected with each other by means of the X2 interface. The radio network nodes are also connected by means of the S1 interface to the EPC, more specifically to the MME by means of an S1-MME interface and to the S-GW by means of an S1-U interface.

The S1-MME interface is used for control plane between the radio network nodes, eNodeB/E-UTRAN and MME. The main protocols used in this interface are S1 Application Protocol (S1-AP) and Stream Control Transmission Protocol (SCTP). S1AP is the application layer protocol between the radio network node and the MME and SCTP for example guarantees delivery of signaling messages between MME and the radio network node. SCTP is capable to transmit several independent streams of chunks of data in parallel, for example transmitting web page images together with the web page text. Several streams, also referred to as SCTP streams, are bundled into a single SCTP association. SCTP is also used between radio base stations over X2 and XW between radio base station and wireless local area network (WLAN) Termination node.

The Radio Network Layer in for instance LTE is on top of a transport layer as shown Fig. 3. The radio network layer may comprise the S1AP layer. The Transport Network layer may comprise a physical layer, a data link layer, an Internet Protocol (IP) layer and an SCTP layer. Within the SCTP association established between a pair of one MME and one radio network node:

- a single pair of stream identifiers is reserved for the sole use of S1 AP elementary procedures that utilize non wireless device-associated signalling.

At least one pair of stream identifiers is reserved for the sole use of S1 AP elementary procedures that utilize wireless device-associated signallings. However a few pair, i.e. more than one, should be reserved.

- A single wireless device-associated signalling uses one SCTP stream and the stream should not be changed during the communication of the wireless device- associated signalling."

Wreless device-associated signalling, also denoted as UE-associated signalling, is described in [1] as:

"UE-associated signalling: When S1-AP messages associated to one UE uses the UE-associated logical S1-connection for association of the message to the UE in eNB and EPC.

UE-associated logical S1 -connection: The UE-associated logical S1-connection uses the identities MME UE S1AP ID and eNB UE S1AP ID according to definition in TS 23.401 [2]. For a received UE associated S1-AP message the MME identifies the associated UE based on the MME UE S1AP ID IE and the eNB identifies the associated UE based on the eNB UE S1AP ID IE. The UE-associated logical S1-connection may exist before the S1 UE context is setup in eNB."

According to [2] the definitions of MME UE S1AP ID and eNB UE S1AP ID are "eNB UE S1 AP ID: Unique identity of the UE within eNodeB

MME UE S1AP ID: Unique identity of the UE within MME"

Which SCTP stream is assigned for non wireless device-associated signalling could be detected by a method such as that the first message sent over the interface is a non-wireless device associated message or by configuration. In SCTP Associations where several wireless device-associated stream pairs are used, the radio network nodes can select any of them. A wireless device associated message received today needs to be handled as follows.

1. The SCTP message with Abstract syntax notation (ASN.1) encoded S1 AP payload is received on one of the wireless device associated streams. ASN.1 is a formal notation used for describing data transmitted by telecommunications protocols.

2. The payload is ASN.1 decoded to retrieve the radio network node-wireless device- S1AP ID

3. The message is routed to its next destination based on the radio network node- wireless device-S1AP ID.

In order to send the information retrieved from SCTP to the next destination the

SCTP payload containing the ASN1 decoded S1AP messaged needs to be at least partly retrieved. This comes with a cost with respect to

Central Processing unit (CPU) cycles

Complexity since functions to retrieve the radio network node wireless device S1 AP ID from an ASN1 encoded message is needed.

In order to avoid retrieving the information from the payload, SCTP streams can, to some extent, be used for routing. However, the destination within the receiving radio network node is decided by the sending radio network node which may result in a limited performance of the wireless communication network.

SUMMARY

An object of embodiments herein is to provide a mechanism for improving performance of the wireless communication network in an efficient manner.

According to an aspect the object is achieved by providing a method performed by a first radio network node for handling communication of a wireless device or another radio network node. The first radio network node has a SCTP association e.g. a S1AP interface, to a second radio network node, which SCTP association comprises one or more streams. The first radio network node determines a stream identity (ID) e.g. a SCTP stream ID, of a stream of the SCTP association for the wireless device or the other radio network node. The first radio network node then sends, to the second radio network node, an indication indicating the determined stream ID of the stream for the second radio network node to use as an incoming stream, to the first radio network node, for data for the wireless device or the other radio network node. Thus, the first radio network node indicates an inbound or incoming stream ID that the second radio network node shall use for a stream for the wireless device or the other radio network node. According to an aspect the object is achieved by providing a method performed by a second radio network node for handling communication of a wireless device or another radio network node. The second radio network node has a SCTP association to a first radio network node, which SCTP association comprises one or more streams. The second radio network node receives, from the first radio network node, an indication of a stream ID of a stream of the SCTP association upon which stream the first radio network node wants to receive from the second radio network node data for a wireless device or another radio network node. The second radio network node stores the indication of the stream ID mapped, e.g. associated with, to the wireless device or the other radio network node. E.g. the second radio network node may store information mapping the wireless device or the other radio network node to the received stream ID. The second radio network node may then perform communication for the wireless device or other radio network node over the stream with the stored stream ID.

According to yet another aspect the object is achieved by providing a first radio network node for handling communication of a wireless device or another radio network node, which first radio network node is configured to have an SCTP association to a second radio network node, which SCTP association comprises one or more streams. The first radio network node is configured to determine a stream identity of a stream of the SCTP association for the wireless device or the other radio network node. The first radio network node is further configured to send to the second radio network node, an indication indicating the determined stream identity of the stream for the second radio network node to use as an incoming stream, to the first radio network node, for data for the wireless device or the other radio network node.

According to still another aspect the object is achieved by providing a second radio network node for handling communication of a wireless device or another radio network node, which second radio network node is configured to have an SCTP association to a first radio network node, and which SCTP association comprises one or more streams. The second radio network node is configured to receive from the first radio network node, an indication of a stream identity of a stream of the SCTP association upon which stream the first radio network node wants to receive from the second radio network node data for a wireless device or another radio network node. The second radio network node is further configured to store the indication of the stream identity mapped to the wireless device or the other radio network node. It is furthermore provided herein a computer program 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 first radio network node or the second radio network node. It is additionally provided herein a computer-readable storage medium, having stored thereon a computer program 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 first radio network node or the second radio network node.

Enabling e.g. an inbound SCTP stream to the receiving first radio network node to be selected by the first radio network node itself, and not by the sending second radio network node, gives one or more advantages such as:

- Efficient routing to processes or processing units within or associated with the first radio network node based on the stream ID is enabled since the receiving first radio network node with the inbound SCTP streams can decide which SCTP stream ID the sending second radio network node selects.

Thus, embodiments herein introduce an efficient manner of handling resources of a receiving radio network node, such as the first radio network node, since the first radio network node may efficiently route and handle SCTP of different wireless device and/or radio network nodes by determining stream IDs associated with processes such as internal units in a balanced and efficient manner. This leads to an improved performance of the wireless communication network.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in more detail in relation to the enclosed drawings, in which:

Fig. 1 is a schematic overview depicting a communication network according to prior art; Fig. 2 is a schematic overview depicting a radio access network in connection with a core network according to the overall E-UTRAN architecture;

Fig. 3 is a schematic overview depicting a protocol stack;

Fig. 4 is a schematic overview depicting a wireless communication network according to embodiments herein;

Fig. 5 is a combined flowchart and signalling scheme according to embodiments herein; Fig. 6 is a block diagram depicting a first radio network node according to embodiments herein;

Fig. 7 is a signalling diagram according to embodiments herein; Fig. 8 is a schematic flowchart depicting a method performed by a first radio network node according to embodiments herein;

Fig. 9 is a schematic flowchart depicting a method performed by a second radio network node according to embodiments herein;

Fig. 10 is a block diagram depicting a wireless device according to embodiments herein; and

Fig. 11 is a block diagram depicting a second radio network node according to

embodiments herein. DETAILED DESCRIPTION

Embodiments herein relate to communication networks in general. Fig. 4 is a schematic overview depicting a wireless communication network 1. The

communication network 1 comprises one or more RANs e.g. a first RAN (RAN 1), connected to one or more CNs. The communication network 1 may use a number of different technologies, such as Wi-Fi, Long Term Evolution (LTE), LTE-Advanced, 5G, Wideband Code Division Multiple Access (WCDMA), Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WMax), 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 a 5G context, however, embodiments are applicable also in further development of the existing communication systems such as e.g. 3G and LTE.

In the wireless communication network 1 , wireless devices e.g. a wireless device 10 such as a mobile station, a non-access point (non-AP) STA, a STA, a user equipment and/or a wireless terminal, are connected via the one or more RANs, to the one or more CNs. It should be understood by those skilled in the art that "wireless device" is a non- limiting term which means any terminal, wireless communication terminal, communication equipment, Machine Type Communication (MTC) device, Device to Device (D2D) terminal, or user equipment e.g. smart phone, laptop, mobile phone, sensor, relay, mobile tablets or any device communicating within a cell or service area.

The wireless communication network 1 comprises a first radio network node 12. The first radio network node 12 is exemplified herein as a RAN node providing radio coverage over a geographical area, a first service area 11 , of a radio access technology (RAT), such as LTE, UMTS, Wi-Fi or similar. The first radio network node 12 may be a radio access network node such as radio network controller or an access point such as a wireless local area network (WLAN) access point or an Access Point Station (AP STA), an access controller, a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB), a base transceiver station, Access Point Base Station, base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit capable of serving a wireless device within the service area served by the first radio network node 12 depending e.g. on the radio access technology and terminology used and may be denoted as a receiving radio network node. The first radio network node 12 may alternatively be a core network node such as an MME e.g. in the case where the communication is performed from the RAN to the CN.

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.

Furthermore, the wireless communication network 1 comprises a second radio network node 13. The second radio network node 13 is exemplified herein as a core network node in the core network such as an MME or other network node with a SCTP association with another radio network node. However, the second radio network node 13 may alternatively be a radio access network node such as radio network controller or an access point such as a wireless local area network (WLAN) access point or an Access Point Station (AP STA), an access controller, a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB), a base transceiver station, Access Point Base Station, base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit capable of using an SCTP association with the first radio network node 12 depending e.g. on the radio access technology and terminology used. The second radio network node 13 may be referred to as sending radio network node. Thus, the second radio network node 13 has one or more SCTP associations e.g. S1 AP SCTP associations or X2AP SCTP associations, where each SCTP association contains or comprises one or more streams, to the first radio network node 12. The radio network nodes 12, 13 may be interconnected with each other by means of one or more S1 interfaces, X2 interfaces or XW interfaces. In the illustrated examples herein the first radio network node 12 is an access point and the second radio network node13 is core network node, however, as stated above may the first radio network node 12 be a core network node and the second radio network node may be an access point 13. The wireless communication network 1 may further comprise a third radio network node 15 that may be a part of a combined node comprising the first radio network node 12 and the third radio network node 15. The third radio network node 15 may be a RAN node providing radio coverage over a geographical area, a second service area 14, of a radio access technology (RAT), such as LTE, UMTS, Wi-Fi or similar. The third radio network node 15 may be a radio access network node such as radio network controller or an access point such as a wireless local area network (WLAN) access point or an Access Point Station (AP STA), an access controller, a base station, e.g. a radio base station such as a NodeB, an evolved Node B (eNB, eNodeB), a base transceiver station, Access Point Base Station, base station router, a transmission arrangement of a radio base station, a stand-alone access point or any other network unit capable of serving a wireless device within the service area served by the third radio network node 15 depending e.g. on the radio access technology and terminology used and may be denoted as a second receiving radio network node. The third radio network node 15 may in some embodiments be a core network node such as an MME being a part of a combined core network node. The second radio network node 13 may be

interconnected to the combined node comprising the first and third radio network node by means of one or more S1 interfaces, X2 interfaces or XW interfaces.

An SCTP association between the first radio network node 12 and the radio network node 13 comprises streams. The payload sent in SCTP may e.g. be an S1AP message or an X2AP message. According to embodiments herein the receiving radio network node, i.e. the first radio network node 12, determines a stream ID of a stream of the SCTP association for the wireless device 10 or the third radio network node 15 e.g. in case of a combined node. The first radio network node 12 then transmits, to the second radio network node 13, an indication indicating the determined SCTP stream ID for the second radio network node to use as a stream for data for the wireless device 10 or the third radio network node 15.

Embodiments herein enable a receiving radio network node, such as the first radio network node 12, to decide which incoming stream, i.e. the stream ID, another SCTP endpoint such as the second radio network node 13 selects for the wireless device 10 or the third radio network node 15 in case of a combined node which is a prerequisite for the receiving first radio network node 12 to route the message to an internal process e.g. a processor without retrieving information from the payload and simultaneously decide the routing destination.

Fig. 5 is a combined flowchart and signalling scheme according to some embodiments herein. This embodiments relates to an S1 SCTP association over an S1 interface thus the second radio network node 13 is an MME and the first radio network node 12 is a radio base station. However there are communications between other radio network nodes where SCTP is part of the protocol stack but S1 AP is not used, such as

X2AP or XWAP communications.

Action 501. The first radio network node 12 determines a stream ID of a SCTP stream out of a number of SCTP streams of the SCTP association for the wireless device 5 10. E.g. the first radio network node 12 assigns a stream ID to an internal unit, of the first radio network node 12, such as a processor, controller, resource unit, or board to handle communication processes for the wireless device 10. Hence, the stream ID is associated to the internal unit such as a routing address to this internal unit (see Fig. 6 below). This may be determined based on processing capacity, a preconfigured function, randomly or 10 similar. The internal unit may be associated with several streams, or stream IDs, hence, the stream ID may be selected among those randomly. Hence, the first radio network node may distribute the tasks/load between available resources or internal units.

Action 502. The first radio network node 12 transmits, to the second radio network node 13, the indication of the determined stream ID. The indication may be the stream ID 15 value or an ID of the wireless device 10 associated to the first radio network node 12 such as a radio network node wireless device S1AP ID. The indication may be sent in payload, e.g. higher layer signaling, or SCTP layer of a message.

Action 503. The second radio network node 13 receives the indication and stores the indication in the second radio network node 13. E.g. the second radio network node 20 13 may, based on the received indication, determine or calculate a suggested stream ID for the wireless device 10 and store the mapping of the stream ID and the wireless device

10.

Action 504. The second radio network node 13 may trigger a transmission of data associated with the wireless device 10. E.g. the second radio network node 13 may obtain 25 data intended for the wireless device 10. The second radio network node 13 may trigger a transmission of control data, received data, a message, data intended for the wireless device 10 to the first radio network node 12. The second radio network node 13 may e.g. receive data intended for the wireless device 10 from another radio network node or if e.g. the second radio network node 13 is configured to start a trace for a wireless device the 30 second radio network node 13 may obtain/create this data internally.

Action 505. The second radio network node 13 then selects the suggested stream ID indicated in the stored indication e.g. based on the ID of the wireless device 10.

Action 506. The second radio network node 13 then transmits the data over the SCTP association with the selected stream ID as indicated in the received indication. E.g. 35 the second radio network node 13 may transmit a DL Non Access Stratum (NAS) signalling to the first radio network node 12 using the indicated stream ID. The second radio network node 13 may also indicate a stream the second radio network node 13 wants its signalling on as well.

Action 507. The first radio network node 12 receives the data over the SCTP association with the stream ID and based on the stream ID the payload is forwarded to the internal unit which is associated with this stream ID i.e. the received is routed and handled to an internal unit at the first radio network node 12. This internal unit then decodes the payload and takes this decoded payload into account for further processing. For any further processing the payload is opened which contains the message, e.g.ASNI coded message according to S1AP spec TS36.413 v.13.0.0, and is then further processed.

Fig. 6 shows an SCTP message containing payload data that is received by the SCTP termination point such as the first radio network node 12. The stream ID on which the payload was received is taken into account for when routing the payload to its next destination which in the Fig. 6 is A2 out of the N possible destinations AI-AN.

This solution can be implemented in a radio network node where SCTP is used for the transport network layer. Fig. 6 illustrates this for the first radio network node 12 receiving an SCTP message on a stream.

61. The SCTP message is received in the first radio network node 12. The payload data and the stream ID are retrieved from the SCTP layer.

62. The payload is forwarded for further processing in one of the node internal units A _n n = 1.. N in a router e.g. based on a function of the received indication.

In some embodiments, different tasks may be handled on different processes such as different hardware and/or in logical entities of the first radio network node 12 as illustrated by the Ai ... AN. These different hardware and/or in logical entities are examples of the internal units mentioned above. To make an efficient node implementation it is beneficial that each receiving radio network node, i.e. the first radio network node 12, decides where and how a task is executed to allow the first radio network node 12 to distribute the tasks/load between the available resources or internal units. In the first radio network node 12 it may be beneficial to distribute the handling of, as an example, wireless devices among several entities. This requires that when the first radio network node 12 has decided to handle the wireless device 10 at a particular internal unit, any signaling regarding the wireless device 10 from other radio network nodes needs to be routed to this internal unit. In SCTP, the streams are unidirectional. An endpoint, e.g. the first radio network node 12 in an SCTP association has a number of incoming, also referred to as inbound, streams on which it receives data for the wireless device 10 or the third radio network node 15 in case of combined node . In E-UTRAN there are rules on how the SCTP 5 streams are used (see above) but these are not sufficient for the receiving first radio network node 12 to decide which stream the sending second radio network node 13 needs to select for a particular wireless device, such as the wireless device 10.

Embodiments are described with reference to Fig. 6. The first radio network node 12 wants to allocate the wireless device 10 to the internal unit A _n (n = 1... N) and needs 10 the other endpoint, the second radio network node 13 to select a suitable stream.

Start condition:

- An SCTP Association exists between the first radio network node 12 and the second radio network node 13

The first radio network node 12 has K inbound streams or SCTP streams and this

15 K is known to the second radio network node 13

The first radio network node 12 uses the identifier of the wireless device 10 associated with the first radio network node 12 denoted Node12_UEID for the wireless device 10. Wireless device-associated logical S1 -connection is an S1 association where both radio network nodes have exchanged their own unique id

20 of the wireless device e.g. eNB UES1 AP ID and MME UE S1AP ID in the case of the connection between eNB and MME.

In some embodiments, when a message comprising the Node12_UEID is sent to the second radio network node 13, the inbound stream ID to the first radio network node 25 12 is added to the message. The second radio network node 13 then stores that the stream id of the inbound stream that shall be used for this wireless device 10 towards the first radio network node 12 until indicated otherwise.

If implementing this on an E-UTRAN interface such as S1-AP it could be added as 30 shown in bold and underlined in the table below.

INITIAL WIRELESS DEVICE MESSAGE

This message is sent by the first radio network node 12 to transfer the initial layer 3 message to the second radio network node 13 over the S1 interface. This is exemplified as an eNB informing the MME but as stated above it may also be the other way around, 35 i.e. the MME informing the eNB. Direction: eNB→ MME

As long as the stream ID, also referred to a SCTP stream ID or inbound stream ID, is not included the inbound stream to the first radio network node 12 remains the same.

However, in some embodiments if the Stream ID is changed, see below, the first radio network node 12 may indicate that the first radio network node 12 has changed the inbound stream, e.g. changed board or processing unit to handle the communication for the wireless device 10. This embodiment enables the first radio network node 12 to decide which of the inbound streams to the first radio network node 12 is selected by the second radio network node 13. A second embodiment enables the first radio network node 12 to change which of the inbound streams to the first radio network node 12 is selected by the second radio network node 13.

When the first message comprising the Node12_UEID is sent to the second radio network node 13 no explicit stream information is included. Instead there exists a function f known in both the first radio network node 12 and the second radio network node 13 describing how the second radio network node 13 selects the stream ID. The indication of the stream ID is thus the wireless device identifier and the second radio network node 13 then stores that the stream id associated with the wireless device identifier shall be used for this wireless device 10 towards the first radio network node 12 until indicated otherwise. Thus, the indication may indicate the stream ID implicitly.

An example of a function f distributing the Node12_UEID over the stream IDs is a modulo operation. Assuming that L inbound streams are for non wireless device

Associated signaling the stream selected by the second radio network node 13 could be f = (Node12_UEID mod (K-L)) + L.

Assuming one common stream and four wireless device Associated streams gives

K = 5 and L = 1.

f = (Node12_UEID mod (5-1)) + 1 = (Node12_UEID mod 4) + 1.

Applying this example to E-UTRAN and the S1AP protocol the Node12_UEID is the first radio network node-wireless device S1AP ID which may be 24 bits long. If the first radio network node 12 supports one non-wireless device associated stream and four wireless device Associated streams the first radio network node 12 may let the two least significant bits indicate the stream, i.e. stream ID, and the remaining 22 bits may be a unique identifier in the internal unit. The benefit with such algorithm is that it is easy for the first radio network node 12 to build the first radio network node wireless device S1AP ID and easy for the second radio network node 13 to decode the stream id from the first radio network node wireless device S1AP ID.

This embodiment also allows the stream or stream ID to be changed by modifying the first radio network node wireless device S1AP ID. If the first radio network node 12 changes the two least significant bits it indicates that the inbound stream to the first radio network node 12 for that specific wireless device 10 should be changed.

The issue with LTE though is that even though the second radio network node 13 identifies the wireless device 10 on the second radio network node wireless device S1AP ID it may regard the changed pair of the first radio network node wireless device S1AP ID and the second radio network node wireless device S1AP ID as an error over the interface. In order to solve this, the message where the first radio network node wireless device S1AP ID is changed may contain a previously used first radio network node wireless device S1AP ID. The new and changed first radio network node wireless device S1AP ID is then added as separate information element containing the new first radio network node wireless device S1AP ID.

Embodiments herein provide further advantages:

- An SCTP endpoint such as the first radio network node 12 is not easily distributed over several Central Processing Unit (CPU) cores. A large radio network node such as a base station would therefore need to mitigate scaling problems regarding to SCTP endpoint by either deploying a more powerful processor managing the work or by establishing more SCTP endpoints which in LTE would correspond to more MMEs for the S1 interface. Looking at, for instance, cloud solutions the size of the base station may grow but the processing capacity of one processor/core is not sufficient to handle the amount of signaling. Deploying more

MMEs comes with additional cost and increased complexity and may not be a cost efficient way to deploy the network, hence, the more efficient routing according to embodiments herein may decrease the overall cost of the network.

The two radio network nodes are enabled to have different number of inbound streams optimized to the needs of each radio network node. In LTE today the standard mandates stream pairs which set restrictions on the implementations. Embodiments herein enable several logical radio network nodes, denoted herein as a combined node, to be hidden behind one S1 interface since more than one radio network node may be associated with the same SCTP association.

Fig. 7 shows how the first radio network node 12 and the second radio network node 13 can select the inbound streams. The radio network nodes use stream 0 for the common signaling and then both radio network nodes have 4 inbound streams for wireless device associated signaling, i.e. K = 5, L=1. Action 701. The first radio network node 12 transmits an S1 Setup Request message on stream 0.

Action 702. The second radio network node 13 responds with a S1 Setup

Response message on stream 0.

Action 703. The first radio network node 12 wants the second radio network node

13 to send information on the inbound stream identified by stream ID 2. The first radio network node 12 thus selects a first radio network node wireless device S1AP ID (eNB- UE-S1AP ID) according to the function f1 in such way that the second radio network node 13 selects the stream accordingly. The first radio network node 12 sends the initial message on stream ID = 0 such as common signaling. The initial message indicates stream ID 2 by selecting the first radio network node wireless device S1AP ID indicating the stream ID 2 with the function, e.g. eNB UE S1AP ID = 181.

Action 704. The second radio network node 13 calculates the stream ID based on the received first radio network node wireless device S1AP ID as f1 = (181 mod (5-1)) + 1 = (181 mod 4) + 1 = 2. The It should also be noted that the first radio network node 12 may be an MME and then the MME may send e.g. a Downlink (DL) NAS Transport message including the radio network node wireless device S1AP ID = 1022 indicating that the MME wants the eNodeB to use stream ID 3 for this wireless device. Thus, the second radio network node 13 may additionally select stream ID for a wireless device and inform the first radio network node 12.

Action 705. The first radio network node 12 may then calculate the stream ID based on the second radio network node wireless device S1AP ID as f2 = (1022 mod (5- 1)) + 1 = (1022 mod 4) + 1 = 3. (In this example f1 = f2 since both nodes have the same number of inbound streams). The first radio network node 12 may then transmit an UL NAS Transport message including the radio network node wireless device S1AP IDs.

Sending the Initial message on the common stream e.g. stream ID=0, is aligned to current specification TS36.412 v.13.0.0 since a stream is not allowed to be changed once wireless device associated signaling is established. Without this requirement it would also be possible to send the initial message on any stream and let the second radio network node 13 move the wireless device to streams internally.

Above shows how the streams are selected for the wireless device 10. However, it is of course possible to select streams based on other criteria than the wireless device. One such example could be if one or more base stations, e.g. the third radio network node 15, are located behind the SCTP termination point such as the first radio network node 12. The first radio network node 12 could then, as an example, select streams based on an identifier of the third radio network node 15 such as a base station identifier, or as a combination of the identifier of the third radio network node 15 and the identifier of the wireless device 10.

This allows messages which are non-wireless device associated to be routed to a correct destination handling processing for the third radio network node 15. The second radio network node 13 may need to have sufficient information to know which stream shall carry which information.

Configuration

- Signaling exchange

Function which takes parameters such as number of base stations, number of established inbound streams into account.

As an example, the second radio network node 13 such as an MME could retrieve the information that a combined node comprises two logical radio network nodes, here indicated as the first radio network node 12 and the third radio network node 15, and the information may further define that:

SCTP Stream 0: Inbound common signaling for the first radio network node 12 to the combined node

- SCTP Stream 1 : Inbound common signaling for the third radio network node 15 to the combined node

SCTP Stream 2: Inbound wireless device associated signaling

SCTP Stream 3: Inbound wireless device associated signaling

SCTP Stream 4: Inbound wireless device associated signaling

- SCTP Stream 5: Inbound wireless device associated signaling

This automatic configuration can be achieved by for example:

The first radio network node 12 sends a S1 Setup Request message to the second radio network node 15 containing an additional list of supported the radio network nodes, in this example this additional list contains the third radio network node 15, and on which inbound SCTP stream to the combined node the second radio network node 13 shall use for each logical radio network node.

The second radio network node 13 may send the S1 Setup Response message to the first radio network node 12 the SCTP stream IDs it would like the other radio network nodes to signal on. The remaining logical radio network node, such as the third radio network node 15, may send a S1 Setup Request message to the second radio network node 13 on the respective stream.

The second radio network node 13 now knows which streams to use to send non- wireless device Associated signaling with each logical radio network node in the combined node.

The combined node and the second radio network node 13 interworks as above to select the appropriate stream id for wireless device associated signaling. The S1 Setup implies that the S1 interface is reset. Each of the S1 Setup messages in the step of sending S1 Setup Responses need to contain an indicator indicating that the information provided in the step of sending requests or in other messages sending S1 responses may not be impacted by a new message comprising the indication.

This can be further generalized to cover signaling common for all radio network nodes in a combined node. This would reduce the signaling over the interface because paging messages to be sent to all logical radio network nodes in the combined node only needs to be sent once. An example of SCTP stream configuration for such setup is:

SCTP Stream 0: Inbound common signaling for all radio network nodes (here first and third) in the combined node

SCTP Stream 1 : Inbound common signaling for the first radio network node 12 to the combined node

SCTP Stream 2: Inbound common signaling for the third radio network node 15 to the combined node

- SCTP Stream 3: Inbound wireless device associated signaling

SCTP Stream 4: Inbound wireless device associated signaling

SCTP Stream 5: Inbound wireless device associated signaling

SCTP Stream 6: Inbound wireless device associated signaling This automatic configuration may be achieved by for example:

The first radio network node 12 sends a S1 Setup Request message to the second radio network node 13 containing an additional list of supported radio network nodes (in this example this additional list contains the third radio network node 15) and on which inbound SCTP stream to the combined node the second radio network node 13 shall use for each logical radio network node and common signaling for all radio network nodes in the combined node.

The second radio network node 13 sends in the S1 Setup Response message to the first radio network node 12 the SCTP stream IDs it would like the other radio network nodes to signal on.

The remaining logical radio network nodes send a S1 Setup Request message to the second radio network node 13 on the respective stream.

The second radio network node 13 now knows which streams to use to send non- wireless device Associated signaling with each logical radio network node in the combined node.

The first radio network node 12 and the second radio network node 13 interworks as above to select the appropriate stream id for wireless device associated signaling.

The method actions performed by the first radio network node 12 for handling communication of the wireless device or another radio network node according to some embodiments will now be described with reference to a flowchart depicted in Fig. 8. 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 first radio network node 12 has an SCTP association to the second radio network node, which SCTP association comprises one or more streams. Thus, the second radio network node 13 has one or more SCTP associations e.g. one S1 SCTP association to the first radio network node 12, wherein each SCTP association comprises one or more streams to the first radio network node 12.

Action 801. The first radio network node 12 determines the stream ID of the stream of the SCTP association for the wireless device 10 or the other radio network node, such as the third radio network node 15 e.g. in case the first and third radio network nodes 15 represents a combined node .

Action 802. The first radio network node 12 may store information indicating that the stream identity is associated with an internal unit, of the first radio network node 12, for processing the data.

Action 803. The first radio network node 12 then sends, to the second radio network node, the indication indicating the determined stream identity of the stream for the second radio network node to use as the incoming stream, to the first radio network node 12, for data for the wireless device or the other radio network node. For example, the first radio network node may transmit, to the second radio network node 13, the indication indicating the determined stream ID for the wireless device 10 or the other radio network node. The indication may be an identity of the wireless device 10 indicating the determined stream identity according to a function using the identity of the wireless device 10. For example, the indication may be the actual stream ID value or an identity indicating the stream ID implicitly by e.g. calculating the stream ID from a function of the identity. This may be for configuring wireless device associated signaling.

Action 804. The first radio network node 12 may then receive data for the wireless device 10 or the other radio network node over the incoming stream with the determined stream identity, e.g. over an SCTP association with the determined stream ID.

Action 805. The first radio network node 12 may further route the data to the process e.g. internal unit or processor, associated with the stream identity based on the stored information.

The method actions performed by the second radio network node 13 for handling communication for the wireless device or another radio network node according to some embodiments will now be described with reference to a flowchart depicted in Fig. 9. 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 second radio network node 13 has the SCTP association to the first radio network node 12, and which SCTP association comprises one or more streams. Thus, the second radio network node has one or more SCTP associations e.g. one S1 SCTP association to the first radio network node 12, wherein each SCTP association comprises one or more streams to the first radio network node 12.

Action 901. The second radio network node 13 receives from the first radio network node, the indication of the stream ID of the stream, such as SCTP stream, of the SCTP association upon which stream the first radio network node 12 wants to receive from the second radio network node 13 data for the wireless device 10 or another radio network node.

Action 902. The second radio network node 13 stores the indication of the stream ID mapped to the wireless device 10 or other radio network node. E.g. the second radio network node 13 may store information mapping the wireless device 10 or the other radio network node to the received stream ID. As an example the second radio network node 13 may store the received S1AP ID from which the second radio network node 13 may recalculate the stream ID every time. The indication may be the identity of the wireless device 10 or the other radio network node, or the indication may be the actual stream ID. Action 903. The second radio network node 13 may, when the received indication is the identity of the wireless device 10, calculate the stream identity based on the identity of the wireless device 10. Thus, the indication may be used to calculate the stream ID, e.g. stream ID = f(stored indication).

Action 904. The second radio network node 13 may then perform the

communication for the wireless device or the other radio network node over the stream with the stream identity indicated by the stored indication. E.g. the second radio network node 13 may trigger transmission of data associated with the wireless device 10 or the other radio network node. The second radio network node 13 may send data over an SCTP association using the stream with the stored stream ID. E.g. the second radio network node 13 may select and use a stream as stored in the second radio network node 13 for the wireless device 10 or the other radio network node.

Fig. 10 is a block diagram depicting the first radio network node 12 for handling communication for the wireless device or another radio network node in the wireless communication network according to embodiments herein. The first radio network node 12 is configured to setup one or more SCTP associations, e.g. S1/X2 SCTP associations, with the second radio network node 13, wherein each SCTP association comprises one or more streams to the first radio network node 12.

The receiving first radio network node 12 such as a radio base station or an MME may comprise a processing unit 1001 , e.g. one or more processors, configured to perform the methods herein.

The first radio network node 12 may comprise a determining module 1002. The first radio network node 12, the processing unit 1001 and/or the determining module 1002 is configured to determine the stream ID, of the stream of the SCTP association, for the wireless device 10 or the other radio network node such as the third radio network node 15 e.g. in case the first and third radio network nodes represents a combined node. The first radio network node 12 may allocate processing resources in an efficient manner by distribute processes of different wireless devices to different processing resources such as internal units.

The first radio network node 12 may comprise a transmitting module 1003. The first radio network node 12, the processing unit 1001 and/or the transmitting module 1003 is configured to send, to the second radio network node 13, the indication indicating the determined stream ID of the stream for the second radio network node to use as the incoming stream, to the first radio network node 12, for the wireless device 10 or the other radio network node. The indication may be the actual stream value or an identity indicating the stream ID implicitly. The indication may be the identity of the wireless device 10 indicating the determined stream identity according to the function using the identity of the wireless device 10. This may be for configuring wireless device associated signaling from the second radio network node 13.

The first radio network node 12 may comprise a receiving module 1004. The first radio network node 12, the processing unit 1001 and/or the receiving module 1004 may be configured to receive data for the wireless device 10 or the other radio network node over the incoming stream with the determined stream ID. The first radio network node 12 may comprise a routing module 1005. The first radio network node 12, the processing unit 1001 and/or the routing module 1005 may be configured to route the data to the process, e.g. processor, associated with the stream identity based on the stored information. The first radio network node12 may thus route the data to a process, e.g. internal unit, associated with that stream ID.

The first radio network node 12 may comprise a storing module 1006. The first radio network node 12, the processing unit 1001 and/or the storing module 1006 may be configured to store the information indicating that the stream identity is associated with an internal unit, of the first radio network node 12, for processing the data.

The first radio network node 12 further comprises a memory 1007. The memory comprises one or more units to be used to store data on, such as stream IDs, wireless device identities, radio network node identities, applications to perform the methods disclosed herein when being executed, and similar. Thus, the first radio network node 12 may comprise the processing unit and the memory, said memory comprising instructions executable by said processing unit whereby said radio network node is operative to perform the methods herein.

The methods according to the embodiments described herein for the first radio network node 12 are respectively implemented by means of e.g. a computer program 1008 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 first radio network node 12. The computer program 1008 may be stored on a computer-readable storage medium 1009, e.g. a disc or similar. The computer-readable storage medium 1009, having stored thereon the computer program, 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 first radio network node 12. In some embodiments, the computer-readable storage medium may be a non-transitory computer-readable storage medium.

Fig. 11 is a block diagram depicting the second radio network node 13 for handling communication of the wireless device 10 or another radio network node 15 according to embodiments herein. The second radio network node 13 is configured to have the SCTP association to the first radio network node 12, and which SCTP association comprises one or more streams. The second radio network node 13 may be configured to setup up one or more SCTP associations e.g. S1/X2 SCTP associations to the first radio network node 12, wherein each SCTP association comprises one or more streams to the first radio network node 12. The second radio network node 13 may comprise a processing unit 1101 , e.g. one or more processors, configured to perform the methods herein.

The second radio network node 13 may comprise a receiving module 1102. The second radio network node 13, the processing unit 1101 and/or the receiving module 1 102 may be configured to receive from the first radio network node 12, the indication of the, suggested, stream ID of the stream, such as SCTP stream, of the SCTP association upon which stream the first radio network node 12 wants to receive from the second radio network node 13 data for the wireless device or the other radio network node.

The second radio network node 13 may comprise a storing module 1103. The second radio network node 13, the processing unit 1 101 and/or the storing module 1 103 is configured to store the indication of the stream ID mapped to the wireless device 10 or the other radio network node. E.g. the second radio network node 13 may be configured to store information mapping the wireless device 10 or the other radio network node to the received stream ID.

The second radio network node 13 may comprise a triggering module 1104. The second radio network node 13, the processing unit 1101 and/or the triggering module 1 104 may be configured to trigger transmission of data, which transmission is associated with the wireless device 10 or the other radio network node. For example, the second radio network node 13 may be configured to obtain data associated with the wireless device 10 or the other radio network node or initiate a trace process of the wireless device 10.

The second radio network node 13 may comprise a selecting module 1105. The second radio network node 13, the processing unit 1 101 and/or the selecting module 1 105 may be configured to select the stream of the SCTP association with the stream ID for the transmission. The received indication may be the identity of the wireless device 10 and/or the second radio network node 13, the processing unit 1 101 and/or the selecting module 1105 may be configured to calculate the stream identity in the function based on the identity of the wireless device 10.

The second radio network node 13 may comprise a transmitting module 1106.

The second radio network node 13, the processing unit 1 101 and/or the transmitting module 1 106 may be configured to perform communication for the wireless device or the other radio network node over the stream with the stream identity indicated by the stored indication. E.g. transmit data over an SCTP association using the stream with the stored stream ID. Thus, the second radio network node 13 may be configured to select and use a stream as stored in the second radio network node 13 for the wireless device 10 or the other radio network node. The second radio network node 13, the processing unit 1101 and/or the transmitting module 1106 may be configured to perform communication for the wireless device or the other radio network node over the stream with the stream identity indicated by the stored indication.

The methods according to the embodiments described herein for the second radio network node 13 are respectively implemented by means of e.g. a computer program 1107 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 second radio network node 13. The computer program 1 107 may be stored on a computer-readable storage medium 1108, e.g. a disc or similar. The computer-readable storage medium 1108, having stored thereon the computer program, 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 second radio network node 13. In some embodiments, the computer-readable storage medium may be a non-transitory computer- readable storage medium.

The second radio network node 13 may further comprise a memory 1109. The memory comprises one or more units to be used to store data on, such as stream IDs, functions to calculate stream ID from wireless device identity or radio network node identity, wireless device IDs, radio network node IDs, applications to perform the methods disclosed herein when being executed, and similar. Thus, the second radio network node 13 may comprise the processing unit and the memory, said memory comprising instructions executable by said processing unit whereby said radio network node is operative to perform the methods herein. 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 radio 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. Other hardware, conventional and/or custom, may also be included. Designers of radio network nodes will appreciate the cost, performance, and maintenance trade-offs inherent in these design choices.

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 and their legal equivalents.

REFERENCES

[1] TS 36.413 V. 13.0.0

[2] TS 23.401 v. 13.0.0