FI113128B - Interworking between different radio access network e.g. for UMTS, involves inter working function using user defined information element of existing protocol - Google Patents

Abstract

The method involves inter working function using a user defined information element of an existing protocol which is used for establishing the data transport bearers to adapt a new protocol for controlling the transport bearers in the Transport Network Layer. An Independent claim is included for a system for controlling an inter working function linked with an ATM transport network

Description

113128

METHOD 'AND SYSTEM FOR IMPLEMENTING THE TRANSMISSION

FIELD OF THE INVENTION

The present invention relates to telecommunications systems. In particular, the present invention relates to a novel and advanced method and system for implementing a mediation protocol in an existing network structure.

BACKGROUND OF THE INVENTION

In current specifications for third generation mobile networks (referred to as UMTSs), the system employs the same well-known architecture as used in all the most common second-generation systems. At present, a block diagram of the system architecture of a UMTS (Universal Mobile Telecommunication System) network is shown in Figure 1. The UMTS network architecture includes a Core Network (CN), a UMTS Terrest-20 rial Radio Access Network (UTRAN), and a User ( UE, User Equipment). The core network is still connected to external networks. : networks, i.e. Internet, PSTN (PSTN, Public * *>

Switched Telephone Network) and / or ISDN (ISDN Integrated Services Digital Network) and / or other public land mobile networks (PLMNs).

The UTRAN architecture comprises a plurality of Radio Network Subsystems (RNS). The RNS is further subdivided into a radio network controller (RNC, Radio 30 Network Controller) and a plurality of base stations (BTS, Base Transceiver Station; called node B in 3GPP specifications). The RNC may have two distinct logical roles relative to the interface with the UE.

»: · · # '' The RNC is called a serving radio network controller; 'J; 35 (SRNC, Serving Radio Network Controller) when it terminates both the IU connection to transfer user data and the corresponding RANAP (Radio Access Net- 113128 2 work Application Part) signaling to / from the CN. The SRNC also has other responsibilities, which include radio resource management operations. The receiving RNC (DRNC, Drift Radio Network Controller) is any RNC other than the SRNC that controls the cell used by the UE. The DRNC is connected to the SRNC via an Iur interface. In this architecture, there are several different connections between network elements. The Iu interface connects the CN to the UTRAN. The IUR interface allows signaling information to be transmitted between two RNCs. There is no interface similar to Iur in second generation cellular network architectures. The signaling protocol over the Iur interface is called a radio network subsystem application part (RNSAP). The RNSAP is terminated at both ends of the Iur interface by the RNC. The Iub interface connects the RNC and Node B.

The iub interface enables the RNC and Node B to negotiate radio resources, for example, adding and deleting Node B-controlled cells to support a designated connection between the UE and the SNRC for transmission-20 and paging control information, and relaying information transmitted through search channels. One Node B can serve one or more cells.

: The UE is connected to Node B via the Uu radio interface. UE

: · Further comprises a subscriber identity module (USIM,:: 25 UMTS Subscriber Identity Module) and a mobile station * · (ME, Mobile Equipment). They are connected via a Cu interface.

Connections to external networks are made by a gateway *, a Gateway MSC (circuit switched networks), or a gateway node in the GPRS network. 30 (GGSN, Gateway GPRS Support Node) (for packet switching networks).

* ··· 'The CN (GSM CN) architecture consists of a Home Location Register (HLR), which is a data base for storing the host copy in the user's service. 35 profiles. In addition, the HLR stores the location of the UE at * * · '· * · [MSC / VLR]' * level (Mobile Services Swithing Center / Visitor Lo 113128 3 cation Register) and / or SGSN: n level. In Figure 1, the CN also comprises an MCS / VLR which is a hub (MSC) and a database (VLR) serving the UE at its current location for circuit-switched services.

A general protocol model for UTRANs is illustrated in Figure 2, and will be explained in more detail below. The structure explained is based on the principle that layers and layers are logically independent of each other.

The protocol structure consists of two main layers, a radio network layer (RNL) and a transmission network layer (TNL). These are shown horizontally in Figure 2. All aspects of the UTRAN are shown only on the radio network layer and the transmission network 15 layer represents the standard transmission technology selected for use in the UTRAN without UTRAN specific modifications. UTRAN has certain special requirements for TNL. For example, the real-time requirement, i.e. the transmission delay must be controllable 20 and kept low.

The control layer includes an application protocol, i.e. RANAP (RANAP, Radio Access Network Application Part), * RNSAP (RNSAP, Radio Network Subsystem Application)

Part) or NBAP (NBAP, Node B Application Part), which is part of the RNL, and a signaling channel, which is part of: TNL, for transmitting application protocol messages. The signaling channel for the application protocol may be the same or different as the signaling connection to ALCAP ( ALCAP, Access Link Control Ap-30 plication Part). ALCAP is a generic name for the protocol or protocols used to establish data transmission channels for the Iu, Iur and Iub interfaces.

*: · ·: Capability Set 2 of the AAL2 Signaling Protocol (ITU-T

·; ··· Q.2630.2, a.k.a. Q.aal2 CS-2) is the selected protocol. 35 for use as ALCAP in UTRAN. Q. 2630.2 adds a new • · · * · * · | optional feature Q.2630.1. * used in the first version of UTRAN.

113128 4 ITU-T Recommendation Q.2630.2 The AAL Type 2 signaling protocol (Capability Set 2) defines the inter-node protocol and node functions that control AAL type 2 point-to-point communications.

5 AAL Type 2 stands for ATM (Asynchronous Transfer Mode) Type 2 (AAL2, ATM Adaptation Layer 2), which is an ATM performance layer that supports variable bit rate, connection oriented, time dependent data traffic. Figure 3 shows an example of the use of Q.2630.2 in connection with a UTRAN for different interfaces.

In the future, the Internet Protocol (IP) will be introduced as a transmission protocol for Radio Access Network (RAN). The so-called IP RAN represents 15 IP base stations (IP BTS or IP BS) which replace the RNC functions of earlier versions of UTRAN in several functions. IP RANs can be connected to other RANs including the UTRAN on GERAN gateways or servers, or connections can be made directly from the IP 20 BTS. IP based RAN is also developed by 3GPP.

In 3GPP 3G System (UMTS) Version 5, IP forwarding is introduced as an alternative to ATM / AAL2. ATM / AAL2, is the only transmission technology in earlier versions of UTRAN1.t. version 99 and version 5. A working version of 5:25 to configure IP migration is currently underway and • aims to complete it by 12/2001. Work in progress: The ongoing work and its results are documented in TR25.933.

Together with the introduction of the new transfer option, it must be ensured that new and existing technologies can work together and together. This is perceived as difficult from both the operator's network development point of view and from the vendors' business: • point of view.

In addition, it is emphasized that the mediation 35 between ATM / AAL2 and IP transmission should be implemented and • · · implemented with changes to existing 1 Rel99 and Rel4 technologies and specifications 113128 5 minimal and mediation "additions" to existing 1 Technology is also limited.

It is an object of the present invention to provide a method for managing a relay function (IWF) on an ATM transmission network. In particular, it is an object of the invention to provide a useful mechanism for carrying out a switching operation such that a new transport protocol can be used in the interface of an existing network structure and in a new structure or 10 elements. It is a further object of the invention to provide such an implementation that changes to existing technology, such as the version 99 and 4 technologies mentioned above, and their configuration are minimal and "additions" to the new technologies of the intermediary function 15 are also minimized.

The invention is characterized in what is stated in the independent claims.

SUMMARY OF THE INVENTION

The invention relates to transmission technologies in a RAN.

In transmission networks (regions), two transmission technologies are used and network elements in two regions must * * '· be adapted to communicate with each other. It should be noted that '' the number of transfer technologies is not limited to two.

·, · 25 The basic premise of the invention is that the existing <: ATM / AAL2 network and its 3GPP specifications should be kept intact for as long as possible. The RAN-based ATM / AAL2 transmission uses AAL2 signaling ALCAPma.

Further, the invention is based on the idea that an existing ALCAP, e.g. Q.2630, is not used exclusively in the ATM / AAL2 domain ALCAPma, i.e. without changes to the configuration, but also as an additional control protocol ': * *: in the IP migration area. This is accomplished by using 35 existing user defined infor- mation ALCAPs. maatioelementtiä. This means that any I M I | Indeed, ALCAP must have an information element whose content can be specified by the service user. In one example, this is accomplished by extending the capabilities of the Q.2630 by using its Service User Transfer Information Element (SUT). The SUT is a select-5 female information element in the Q.2630 Generation Request message that can transparently transport information from one AAL2-served user to another (parallel AAL2-serving user). According to the above recommendations, the length of the SUT is 1-254 ok-10 volts. In the present invention, the SUT transparently transmits all IP-related transmission information between parallel Q.2630 entities on the network.

The advantages of the present invention can be summarized as follows. When implementing a new transfer layer protocol, a new ALCAP protocol11 is not required. Instead, the existing ALCAP, i.e. Q.2630 in one example may also be used in the new protocol, i.e. IP side. The signaling channel over Q.2630 over IP 20 is already available in version 99. Further, only a subset of the existing ALCAP (Q.2630) has to be implemented on IP-based RAN nodes, thereby reducing the amount of transmission caused by the relay operation. overload and only minor modifications to existing ATM / AAL2-: 25 network elements are required.

! There is still no need for radio network layer · · relay functions because the standard RANAP / RNSAP / NBAP can be used without new information elements. Your mediation function can be implemented in Vt 30 and can only be used on the transmission network layer. Also, there is no need to know the type of adjacent RAN ·; * 'node (IP / ATM) in advance. The type is implicitly defined by its transport layer address type ·; · *! leading to either the original operation or an operation with 35 TNL IWFs. Further, the invention has no limitations on the location of the relay function (IWF), but can be either a standalone node or part of any RAN or IP RAN node. The invention facilitates transmission between different radio access networks.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated by reference in order to facilitate the understanding of the invention, which form part of this specification, illustrate embodiments of the present invention and in conjunction therewith help to explain the principles of the invention. In the drawings: FIG. 1 is a block diagram showing an exemplary prior art arrangement with respect to current cellular networks;

Figure 2 is a general protocol model for the UTRAN interfaces of Figure 1; Figure 3 is a signaling diagram illustrating an example of using Q.2630.2 in connection with a UTRAN;

Fig. 4 is a block diagram illustrating an embodiment of the invention; and

Figures 5a and 5b form a signaling scheme 20 illustrating an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION ', * ·: embodiments of the invention, examples of which are described below; 25 in the drawings.

The following are four different examples of use for the present invention. These examples relate to possible handover situations in the current ATM-based UTRAN. It should be noted that these examples are provided with reference to UTRAN; ** and AAL2 (Q.2630) signaling as ALCAP and assuming ... "that the new protocol is IP. However, the invention is not limited to these.

Figure 4 shows the involved ones with AAL2

• I

35 service users and their logical location according to an invention »* i * .V. In Fig. 4, the left '*' · side represents the ATM / AAL2 area and the right side shows the IP-8 113128 area. In the middle is your brokerage IWF. The IWF can be implemented as a standalone node or as part of any other network node, for example an IP BTS, an RNC, a gateway or a server.

5 ALCAP connections, i.e. Q.2630 in this example cat always passes through the IWF. Thus, the IWF terminates the Q.2630 on both sides and acts as an AAL2-served user. The radio network layer signaling does not have to pass through the IWF at all. This is one of the advantages of the invention.

On the ATM / AAL2 side, Q.2630 is used in exactly the same way as defined in the UTRAN specifications of 3GPP so far. On the IP side, only the SUT (Served User Transport) information element and its contents as well as the Binding ID (B-ID) are relevant to the UTRAN's IP node. The term Sig bearer in Figure 4 refers to the ALCAP signaling channel and is defined in the above specifications. The designations L1 and L2 refer to the terms layer 1 and layer 2, respectively.

The following is a more detailed description of specific embodiments of the invention. In this example, the embodiments of the invention cover the following situations:> · 'Establishing / releasing Iur on a V · ATM / AAL2 area per IP area.

v;, · '25 Connecting / Unlocking with Iur; ··: From IP to ATM / AAL2. This is also shown; | 5a and 5b.

, ··. Connecting / Unblocking with Iub> »ATM / AAL2 RNC to IP Base Station.

... 30 Connecting / Unblocking with Iub »* · IP from RNC to ATM / AAL2 Base Station.

* · '··' It is also noted that the Iur interface *: * *: always establishes a transport channel on a particular serving ·; ··· RNC. Thus, in the physical sense, the Iur formation 35 can begin at either end of the Iur. With Iub * t ·, the transport channel is always formed and released by the controlling RNC. Node B will never form or release

»MM

113128 9

Iub transmission channels. These principles are in line with current 3GPP specifications.

In the first example, the SRNC in the ATM / AAL2 initiates transmission channel establishment by transmitting a corresponding RNSAP message on the radio network layer. Thereafter, the receiving RNC is assumed to respond by sending an RNSAP response message. The response includes the required transport information such as the destination IP address and the UDP port. In addition, the Binding ID is included. 10 The transfer information is checked by the SRNC and when the destination address is other than the ATM termination system address (AE-SA), the SRNC application logic determines that the IWF is required. The IWF is found either by using the default IWF (RNC specific, physical signaling interface specific or logical signaling interface specific) or by retrieving the IWF based on the address information. In this case, an adaptation table can be used in the SRNC with the input (IWF address (AESA)) for each IP RNC. The IWF information can also be in a central location if-20 I got to a network that is accessed by each RNC similar to the name server (DNS) in the IP world. The information that the SRNC needs is the IWF:: routable address. RNCs having ATM / AAL2- only; : interfaces, this address must be an ATM termination. . 25 system type addresses.

Once the IWF address has been found, the ALNCAP of the SRNC is called. sends a standard Q.2630 Build Request (ERQ) per IWF. The optional served user transfer IE si is stored here and includes the transfer 30 address information initially received from: DRNC. When the IWF receives the ERQ, it checks the I I *: lit: SUT and finds the IP transfer information. The IWF adapts the AAL2 / ATM interface and the IP interface and allocates the necessary resources. Then ALCAP in IWF transmits. 35 ERQ 'per DRNC. ERQ 'represents a normal connection request, except that connection endpoint information »may be zero. The SUT now includes a destination address and 113128 10 new IWF UDP ports (the port used by the IWF to receive data from the DRNC side). The Binding ID (B-ID) is transported normally in the served User Generated Reference (SUGR) IE. B-ID is the only one initially allocated by DRNC). The DRNC signaling address is determined by the IWF based on the default address or DRNC IP address information (received in the ERQ SUT from the SRNC). The DRNC recognizes the received ERQ '. The DRNC sends a gain (ECF ') ta-10 to the IWF. The IWF then sends the Q.2630 Generation Confirmation (ECF) back to the SRNC. From the SRNC's point of view, there is now a transmission channel between the SRNC and the DRNC.

The transmission channel release is implemented by default on the SRNC in the same way. There is no need for any TNL signaling message on the IP side of the IWF.

On the ATM / AAL2 side, release is done according to Q.2630, initialized by RNC. The IWF frees the AAL2 connection resource and removes the connection and IP address and 20 UDP ports. The RNC on the IP side works similarly to everything in an IP situation (i.e. no IWF); the connection resource is released based on the RNL signaling functions. Binding ID is not required and is not used here.

'When the transport channel is established on the IP side:: 25 Iur, see Figures 5a and 5b, message sequence by RNL; is just like any other | | imaging. The RSNC now initiates the procedure by sending a radio link reconfiguration request to the DRNC. The DRNC on the ATM / AAL2 side transmits an RNSAP response message to the RSNC 30 and includes all necessary transmissions; (B-ID, AESA) as defined in the RNSAPs> ·; · 'specification [TS25.423 v3.00 (Rel99) and v4.00 (Rel4)]. When the SRNC on the IP side detects that the transfer address type is not IP, it determines that the IWF 35 is required. The IWF (its address) »t * associated with this case is found in one of the first described cases (RNC) described above. When the IWF is found at 11312811 (its signaling address), the ERQ 'is transmitted to it (Q.2630 over SigTran). ERQ 'includes SUT IE carrying the destination IP address and SRNC UDP port and SUGR IE carrying the B-ID originally named DRNC and 5AEA carrying the DRNC AESA. As soon as the IWF receives the ERQ ', it initiates a connection per DRNC (in the ATM / AAL2 area) by sending a standard Q.2630 ERQ copied from the ERQ' B-ID and AESA. The DRNC then responds by sending the ECF 10 back to the IWF. Once the EFC is received, it triggers the IWF to send the ECF 'back to the SRNC. This ECF 'is a standard ECF, but equipped with SUT [Note: this is the only change needed in Q.2630]. SUT carries the IWF IP address and the UDP-15 port.

The transport channel release is done by sending a Q.2630 release message (REL ') from the SRNC (IP) to the IWF. Based on the received REL ', the IWF cleans the pass-through and the IP resources and sends 20 RELs to the DRNCs according to the Q.2630 release procedure.

On the Iub, all the control functions of the connection transport channel are initialized by the RNC controlling the base station (BS). The transmission channel establishment v * is initiated as soon as the NBAP response is received by 25 RNCs from the BS. The response (to the originally sent: * NBAP configuration request) contains the transport layer information ,,.: (Binding ID, IP address, and UDP port). The RNC recognizes, ·· *, a non-AESA address and determines that an IWF is required.

The correct IWF is found as described above in case 30 1. The ALCAP in the RNC then transmits Q.2630 per ERQ • '' on the IWF provided with SUT IE including IP transfer information, SUGR including B-ID, and so on.

; >> · The receiving IWF then sends the ERQ 'to the BS with a SUT containing the IWF IP-35 address and the UDP port. BS acknowledges by sending '· *. * ECF' back to IWF. The IWF then responds to the * RNC by sending a normal ECF to it.

113128 12

The connection is released as in the first case. ALCAP signaling is not needed in TNL on the IP side of IWF.

The RNC with an IP interface receives an NBAP response from the 5 BSs, carrying an AESA-type transfer address. It shows that IWF is needed. The IWF is found and the RNC transmits per ERQ 'to the IWF with a SUT that carries the RNC's IP address and UDP port. The SUGR carries the B-ID. CEID is zero because it is not needed in 10 IWFs. Once the IWF has received the ERQ ', it starts a normal Q.2630 connection per BS using the B-ID received in the ERQ'. As soon as the ECF is received from the BS, the IWF transmits the ECF to the RNC including the SUT containing the IWF IP address and 15 UDP ports.

The transport channel is released by the RNC in the same way as in the other case.

It will be apparent to one skilled in the art that as technology advances, the basic idea of the invention can be implemented in a variety of ways and in multiple network environments. The invention and its applications are thus not limited to the examples described herein, but may vary *! within the scope of the appended claims.

i '.'25 * <»» »il1 • · I» »1 ·

Claims (25)

1. A method for controlling a coordination function linked to an ATM transport network, characterized in that the coordination function uses a user-defined information element of the existing protocol, which protocol is used to form data transport connections, for arranging the new protocol for controlling the transport connections in the transport network layer. 10 2. A method according to claim 1, characterized in that said ATM transport network is used in radio access networks; ooh that the existing protocol is an ALCAP protocol based on AAL2 signaling. 15 3. A method according to claim 2, characterized in that said AAL2 signaling is based on ITU recommendation Q.2630. 4. A method according to claim 3, characterized in that, as the user-defined information element of the existing ALCAP protocol, the Q.2630 signaling serving service transport element (SUT, Served User Transport) is used. 5. A method according to claim 1, characterized in that said user-defined information element is used in the new protocol for transporting information needed by the existing ALCA protocol. 6. A method according to claim 1, characterized in that the user is defined by the user. The information element is connected to the existing "T ALCAP Protocol" confirmation message (Establish Confirm). ; ··! 7. A method according to claim 2, characterized in that upon receiving the radio access * node address information, 113128 is checked if the address information is compatible with the address space of the receiving protocol and if all the address information is not compatible, it is defined address of the coordination function. 5 8. The method of claim 7, wherein the address of the coordination function is defined as the wait value for each network node. 9. A method according to claim 7, characterized in that the address of the coordinating function is interrogated from the centralized point of the network. Method according to claim 7, characterized in that the address of the coordination function is defined at the base of a physical port from which the application protocol was received. 15 11. A method according to claim 7, characterized in that the address of the coordination function is defined on the basis of a logical port from which the application protocol was received. Method according to claim 7, characterized in that the examination is carried out using the address field information field, which indicates at least one of the following, the type of the network node, ·. in the type of address and the type of transport layer. Method according to claim 7, characterized in that the examination is performed using the node type information field, which indicates at least one of the following, the type of the network node, the type of », ···, the address and type of the transport layer. 14. A method according to claim 7, characterized in that the examination is performed using the information layer type field, which indicates at least one of the following, the type of the network node, the type of address and the type of the transport layer. 15. A method according to claim 1, characterized in that the first interface of the existing protocol and the second interface of the new protocol are arranged in the coordination function on the base 113128 of the information in the user-defined element. 16. A method according to claim 1, characterized in that said coordination function is realized as an independent node in the ATM transport network. 17. A method according to claim 1, characterized in that the coordination function is realized as an independent node in the transport network. 10 18. A method according to claim 1, characterized in that the coordination function is realized as part of the network node in the ATM transport network. 19. A method according to claim 1, characterized in that the coordination function is implemented as part of the network node in the transport network. 20. A method according to claim 17 or 19, characterized in that the transport network is based on IP networks. 21. A system for controlling a coordination function linked to an ATM transport network, characterized in that the coordination function includes; arranging the entity, which is: arranged for use by a user-defined information element of the existing protocol; j which protocol is used for forming data transport connections, for arranging a new protocol for controlling the transport connections in the transport network layer. 22. A system according to claim 21, characterized in that said ATM transport network is used in a radio access network; and that the existing protocol is an ALCAP protocol based on AAL2 signaling. 23. A system according to claim 22, characterized in that the AAL2 signaling is based on ITU's recommendation Q.2630. 113128 The system according to claim 23, characterized in that, as defined by the user, the information element of the existing protocol, the Q.2630 signaling serving service transport element (SUT) is used. 25. The system of claim 21, c h a r a c t e r i s e d in that the system further includes a review entity for review if the address information is compatible with the receiving address space upon receipt of the radio access network node address information; and the address defining entity for defining the coordinate function address. 1>