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Title:
METHOD AND APPARATUS FOR SELECTING THE NETWORK ACCESS TYPE (3GPP OR NON-3GPP) WHEN MAKING MOBILE TERMINATED SHORT MESSAGE SERVICE (MT-SMS) DELIVERY OVER NON-ACCESS STRATUM (NAS) IN 5G COMMUNICATIONS SYSTEMS
Document Type and Number:
WIPO Patent Application WO/2019/081032
Kind Code:
A1
Abstract:
A method for configuring an access and mobility function node in communication with at least one user equipment over a control plane, the method comprising: configuring the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and exchanging the messages via the same access type based on the configuring.

Inventors:
WON SUNG HWAN (KR)
LEIS PETER (DE)
Application Number:
EP2017/077512
Publication Date:
May 02, 2019
Filing Date:
October 26, 2017
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
NOKIA SOLUTIONS & NETWORKS OY (FI)
International Classes:
H04W4/12; H04L12/58; H04L29/08; H04W4/00; H04W48/00; H04W48/18; H04W72/04; H04W88/10; H04W88/18
Foreign References:
Other References:
NOKIA ET AL: "SMS transport over NAS", vol. CT WG1, no. Krakow (Poland); 20170821 - 20170825, 25 August 2017 (2017-08-25), XP051327406, Retrieved from the Internet [retrieved on 20170825]
HUAWEI ET AL: "TS 23.502: Common MT SMS procedure to cover multiple cases", vol. SA WG2, no. Sophia Antipolis, France; 20170821 - 20170825, 29 August 2017 (2017-08-29), XP051335560, Retrieved from the Internet [retrieved on 20170829]
NOKIA ET AL: "Correction to MT SMS over NAS via non 3GPP access", vol. SA WG2, no. Sophia Antipolis, France; 20170821 - 20170825, 21 August 2017 (2017-08-21), XP051325350, Retrieved from the Internet [retrieved on 20170821]
"3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; System Architecture for the 5G System; Stage 2 (Release 15)", 3GPP STANDARD; 3GPP TS 23.501, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE ; 650, ROUTE DES LUCIOLES ; F-06921 SOPHIA-ANTIPOLIS CEDEX ; FRANCE, vol. SA WG2, no. V1.4.0, 28 September 2017 (2017-09-28), pages 1 - 151, XP051337397
HUAWEI ET AL: "TS23.502 NF services supported by AMF-system procedures", vol. SA WG2, no. Busan, Korea; 20170327 - 20170331, 26 March 2017 (2017-03-26), XP051247960, Retrieved from the Internet [retrieved on 20170326]
"3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; 5G System - Phase 1; CT WG1 Aspects (Release 15)", 10 September 2017 (2017-09-10), XP051314516, Retrieved from the Internet [retrieved on 20170910]
"3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Procedures for the 5G System; Stage 2 (Release 15)", 3GPP STANDARD; 3GPP TS 23.502, 3RD GENERATION PARTNERSHIP PROJECT (3GPP), MOBILE COMPETENCE CENTRE ; 650, ROUTE DES LUCIOLES ; F-06921 SOPHIA-ANTIPOLIS CEDEX ; FRANCE, vol. SA WG2, no. V1.2.0, 22 September 2017 (2017-09-22), pages 1 - 165, XP051337116
None
Attorney, Agent or Firm:
GARY JOHN SMITH et al. (GB)
Download PDF:
Claims:
Claims

1. A method for configuring an access and mobility function node in communication with at least one user equipment over a control plane, the method comprising:

configuring the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and

exchanging the messages via the same access type based on the configuring.

2. The method as claimed in claim 1 , wherein configuring the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type comprises:

receiving a new transaction identifier from a short message service function node; and defining for the messages exchanged between the access and mobility function node and the at least one user equipment the access type based on the transaction identifier.

3. The method as claimed in claim 2, wherein receiving a new transaction identifier from a short message service function node comprises receiving a new transaction identifier from a short message service function node for the at least one user equipment, the new transaction identifier within a Namf_Communication_N1 N2MessageTransfer service operation message.

4. The method as claimed in any of claims 2 to 3, further comprising storing the new transaction identifier to use for any subsequent messages exchanged between the access and mobility function node and the at least one user equipment associated with the user equipment terminated short message service are communicated via the same access type.

5. The method as claimed in any of claims 1 to 4, further comprising:

receiving at the access and mobility function node a request enabling reachability of the at least one user equipment from a short message service function node;

responding at the access and mobility function node to the request with an access type indicator, wherein the access type indicator is used to configure the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type.

6. The method as claimed in claim 5 when dependent on any of claims 2 to 4, wherein the transaction identifier is based on the access type indicator.

7. The method as claimed in any of claims 1 to 6, wherein configuring the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type further comprises:

receiving a message transfer service operation request to forward a short message service message to the at least one user equipment;

defining for the messages to forward a short message service message to the at least one user equipment the access type;

receiving from the at least one user equipment further messages associated with the short message service message via the same access type;

forwarding to a short message service function node an indicator identifying the access type such that further messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via the same access type.

8. A method for configuring an user equipment in communication with at least one access and mobility function node over a control plane, the method comprising:

configuring the user equipment to communicate with the access and mobility function node such that messages exchanged between the access and mobility function node and the user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and

exchanging the messages via the same access type based on the configuring.

9. The method as claimed in claim 8, wherein configuring the user equipment to communicate with the access and mobility function node such that messages exchanged between the access and mobility function node and the user equipment associated with a user equipment terminated short message service are communicated via a same access type comprises: receiving a short message service body message from the access and mobility function node via an access type; and

transmitting any further messages from the at least one user equipment associated with the short message service body message via the access type.

10. A method for configuring at least one short message service function node in communication with at least one access and mobility function node over a control plane, the at least one access and mobility function node further in communication with at least one user equipment over the control plane, the method comprising:

communicating to the access and mobility function node to configure the access and mobility function node such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction.

1 1 . The method as claimed in claim 10, further comprising:

transmitting to the at least one access and mobility function node a request enabling reachability of the at least one user equipment from the at least one short message service function node; and

receiving from the at least one access and mobility function node a response to the request with an access type indicator, wherein the access type indicator, wherein communicating to the access and mobility function node to configure the access and mobility function node such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction comprises transmitting the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function node selects an access type to communicate messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator.

12. The method as claimed in claim 10, further comprising receiving a short message service function node an access type indicator, the access type indicator based on a determination by the access and mobility function node of an access type of at least one message associated with the short message service message received at the access and mobility function node from the at least one user equipment, wherein communicating to the access and mobility function node to configure the access and mobility function node such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction comprises transmitting the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function node selects an access type to communicate messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator.

13. The method as claimed in any of claims 10 to 12, further comprising transmitting a transaction identifier for the at least one user equipment to the at least one access and mobility function node, the new transaction identifier being within a Namf_Communication_N1 N2MessageTransfer service operation message, and wherein the at least one access and mobility function node is configured to define for the messages exchanged between the access and mobility function node and the at least one user equipment the access type based on the transaction identifier.

14. The method as claimed in claim 13 when dependent on any of claims 1 1 and 12 wherein the transaction identifier is the access type indicator.

15. The method as claimed in any of the claims 1 to 14, wherein the access type comprises one of:

non-access stratum via non-3GPP access; and

non-access stratum via 3GPP access.

16. The method as claimed in any of claims 1 to 15, wherein exchanging the messages comprises exchanging:

at least one downlink non-access stratum transport message comprising a short message service body;

at least one uplink non-access stratum transport message comprising a short message service acknowledgement;

at least one uplink non-access stratum transport message comprising a short message service delivery report; and

at least one downlink non-access stratum transport message comprising a short message service delivery report acknowledgement.

17. The method as claimed in any of claims 1 to 16, wherein exchanging the messages comprises exchanging short message control protocol messages.

18. An apparatus for operating as an access and mobility function, the access and mobility in communication with at least one user equipment over a control plane, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are caused, with the at least one processor to:

configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and

exchange the messages via the same access type based on the configuring.

19. The apparatus as claimed in claim 18, wherein the processor caused to configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type is further caused to:

receive a new transaction identifier from a short message service function node; and define for the messages exchanged between the access and mobility function and the at least one user equipment the access type based on the transaction identifier.

20. The apparatus as claimed in claim 19, wherein the processor caused to receive a new transaction identifier from a short message service function is further caused to receive a new transaction identifier from a short message service function for the at least one user equipment, the new transaction identifier within a Namf_Communication_N1 N2 essageTransfer service operation message.

21 . The apparatus as claimed in any of claims 19 to 20, the processor further caused to store the new transaction identifier to use for any subsequent messages exchanged between the access and mobility function and the at least one user equipment associated with the user equipment terminated short message service are communicated via the same access type.

22. The apparatus as claimed in any of claims 18 to 21 , the processor further caused to: receive at the access and mobility function a request enabling reachability of the at least one user equipment from a short message service function node;

respond at the access and mobility function to the request with an access type indicator, wherein the access type indicator is used to configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type.

23. The apparatus as claimed in claim 22 when dependent on any of claims 19 to 21 , wherein the transaction identifier is based on the access type indicator.

24. The apparatus as claimed in any of claims 18 to 23, wherein the processor caused to configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type is further caused to:

receive a message transfer service operation request to forward a short message service message to the at least one user equipment;

define for the messages to forward a short message service message to the at least one user equipment the access type;

receive from the at least one user equipment further messages associated with the short message service message via the same access type;

forward to a short message service function an indicator identifying the access type such that further messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via the same access type.

25. An apparatus for operating as an user equipment, the user equipment in communication with at least one access and mobility function over a control plane, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are caused, with the at least one processor to:

configure the at least one user equipment to communicate with the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and exchange the messages via the same access type based on the configuring.

26. The apparatus as claimed in claim 25, wherein the processor caused to configure the user equipment to communicate with the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type is further caused to:

receive a short message service body message from the access and mobility function via a access type; and

transmit any further messages from the at least one user equipment associated with the short message service body message via the access type.

27. An apparatus for operating as a short message service function, the short message service function in communication with at least one access and mobility function over a control plane, the at least one access and mobility function further in communication with at least one user equipment over the control plane, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are caused, with the at least one processor to:

communicate to the access and mobility function to configure the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction.

28. The apparatus as claimed in claim 26, the at least one processor further caused to: transmit to the at least one access and mobility function a request enabling reachability of the at least one user equipment from the at least one short message service function node; and

receive from the at least one access and mobility function a response to the request with an access type indicator, wherein the access type indicator, wherein the processor caused to communicate to the access and mobility function to configure the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction is further caused to transmit the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function selects an access type to communicate messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator.

29. The apparatus as claimed in claim 28, the processor is further caused to receive a short message service function an access type indicator, the access type indicator based on a determination by the access and mobility function of an access type of at least one message associated with the short message service message received at the access and mobility function from the at least one user equipment, wherein the processor caused to communicate to the access and mobility function to configure the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction is further caused to transmit the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function selects an access type to communicate messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator.

30. The apparatus as claimed in any of claims 27 to 29, the processor further caused to transmit a transaction identifier for the at least one user equipment to the at least one access and mobility function node, the new transaction identifier being within a Namf_Communication_N 1 N2MessageTransfer service operation message, and wherein the at least one access and mobility function is configured to define for the messages exchanged between the access and mobility function and the at least one user equipment the access type based on the transaction identifier.

31. The apparatus as claimed in claim 30 when dependent on any of claims 28 and 29 wherein the transaction identifier is the access type indicator.

32. The apparatus as claimed in any of the claims 18 to 31 , wherein the access type comprises one of:

non-access stratum via non-3GPP access; and

non-access stratum via 3GPP access.

33. The apparatus as claimed in any of claims 18 to 32, wherein the processor caused to exchange the messages is caused to exchange: at least one downlink non-access stratum transport message comprising a short message service body;

at least one uplink non-access stratum transport message comprising a short message service acknowledgement;

at least one uplink non-access stratum transport message comprising a short message service delivery report; and

at least one downlink non-access stratum transport message comprising a short message service delivery report acknowledgement.

34. The apparatus as claimed in any of claims 18 to 33, wherein the messages comprise short message control protocol messages.

Description:
METHOD AND APPARATUS FOR SELECTING THE NETWORK ACCESS

TYPE (3GPP OR NON-3GPP) WHEN MAKING MOBILE TERMINATED SHORT MESSAGE SERVICE (MT-SMS) DELIVERY OVER NON-ACCESS STRATUM

(NAS) IN 5G COMMUNICATIONS SYSTEMS

Field

The present application relates to a method, apparatus, and computer program and in particular but not exclusively to methods, apparatus, and computer programs related to management and transmission of short message service (SMS) communications with respect to 3GPP based communications.

Background

A communication system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and/or other nodes by providing carriers between the various entities involved in the communications path. A communication system can be provided for example by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and/or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet.

In a wireless communication system at least a part of a communication session between at least two stations occurs over a wireless link. Examples of wireless systems comprise public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). The wireless systems can typically be divided into cells, and are therefore often referred to as cellular systems.

A user can access the communication system by means of an appropriate communication device or terminal. A communication device of a user is often referred to as user equipment (UE) or mobile station (MS). A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other users. The communication device may access a carrier provided by a station, for example a base station of a cell, and transmit and/or receive communications on the carrier.

The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which shall be used for the connection are also typically defined. An example of attempts to solve the problems associated with the increased demands for capacity is an architecture that is known as the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The LTE is being standardized by the 3rd Generation Partnership Project (3GPP). The various development stages of the 3GPP LTE specifications are referred to as releases. Certain releases of 3GPP LTE (e.g., LTE Rel-1 1 , LTE Rel-12, LTE Rel-13) are targeted towards LTE-Advanced (LTE- A). LTE- A is directed towards extending and optimising the 3GPP LTE radio access technologies. Another proposed communication system is a 5G network or a communication network which comprises enhancements for machine type communications or to support services for the Internet of Things.

According to 3rd Generation Partnership Project (3GPP) technical specifications 23.501 and 23.502, the 5G core network can choose to make mobile terminated (MT) short message service (SMS) delivery over non-access stratum (NAS) via non-3GPP access in addition to 3GPP access. This may be compared to the 4G core network, evolved packet core (EPC) which can perform SMS delivery over NAS only via 3GPP access. The MT SMS over NAS via non-3GPP access procedure is being defined currently. However current approaches risk the process being significantly complex.

Summary

In a first aspect there is provided a method for configuring an access and mobility function node in communication with at least one user equipment over a control plane, the method comprising: configuring the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and exchanging the messages via the same access type based on the configuring.

Configuring the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type may comprise: receiving a new transaction identifier from a short message service function node; and defining for the messages exchanged between the access and mobility function node and the at least one user equipment the access type based on the transaction identifier. Receiving a new transaction identifier from a short message service function node may comprise receiving a new transaction identifier from a short message service function node for the at least one user equipment, the new transaction identifier within a Namf_Communication_N1 N2MessageTransfer service operation message.

The method may further comprise storing the new transaction identifier to use for any subsequent messages exchanged between the access and mobility function node and the at least one user equipment associated with the user equipment terminated short message service are communicated via the same access type.

The method may further comprise: receiving at the access and mobility function node a request enabling reachability of the at least one user equipment from a short message service function node; responding at the access and mobility function node to the request with an access type indicator, wherein the access type indicator is used to configure the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type.

The transaction identifier may be based on the access type indicator.

Configuring the access and mobility function node to communicate with the at least one user equipment such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type further may comprise: receiving a message transfer service operation request to forward a short message service message to the at least one user equipment; defining for the messages to forward a short message service message to the at least one user equipment the access type; receiving from the at least one user equipment further messages associated with the short message service message via the same access type; forwarding to a short message service function node an indicator identifying the access type such that further messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via the same access type.

According to a second aspect there is provided a method for configuring an user equipment in communication with at least one access and mobility function node over a control plane, the method comprising: configuring the user equipment to communicate with the access and mobility function node such that messages exchanged between the access and mobility function node and the user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and exchanging the messages via the same access type based on the configuring. Configuring the user equipment to communicate with the access and mobility function node such that messages exchanged between the access and mobility function node and the user equipment associated with a user equipment terminated short message service are communicated via a same access type may comprise: receiving a short message service body message from the access and mobility function node via an access type; and transmitting any further messages from the at least one user equipment associated with the short message service body message via the access type.

According to a third aspect there is provided a method for configuring at least one short message service function node in communication with at least one access and mobility function node over a control plane, the at least one access and mobility function node further in communication with at least one user equipment over the control plane, the method comprising: communicating to the access and mobility function node to configure the access and mobility function node such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction.

The method may further comprise: transmitting to the at least one access and mobility function node a request enabling reachability of the at least one user equipment from the at least one short message service function node; and receiving from the at least one access and mobility function node a response to the request with an access type indicator, wherein the access type indicator, wherein communicating to the access and mobility function node to configure the access and mobility function node such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction may comprise transmitting the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function node may select an access type to communicate messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator.

The method may further comprise receiving a short message service function node an access type indicator, the access type indicator based on a determination by the access and mobility function node of an access type of at least one message associated with the short message service message received at the access and mobility function node from the at least one user equipment, wherein communicating to the access and mobility function node to configure the access and mobility function node such that messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction may comprise transmitting the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function node may select an access type to communicate messages exchanged between the access and mobility function node and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator.

The method may further comprise transmitting a transaction identifier for the at least one user equipment to the at least one access and mobility function node, the new transaction identifier being within a Namf_Communication_N1 N2MessageTransfer service operation message, and wherein the at least one access and mobility function node may be configured to define for the messages exchanged between the access and mobility function node and the at least one user equipment the access type based on the transaction identifier.

The transaction identifier may be the access type indicator.

The access type may comprise one of: non-access stratum via non-3GPP access; and non-access stratum via 3GPP access.

Exchanging the messages may comprise exchanging: at least one downlink non- access stratum transport message comprising a short message service body; at least one uplink non-access stratum transport message comprising a short message service acknowledgement; at least one uplink non-access stratum transport message comprising a short message service delivery report; and at least one downlink non-access stratum transport message comprising a short message service delivery report acknowledgement.

Exchanging the messages may comprise exchanging short message control protocol messages.

According to a fourth aspect there is provided an apparatus for operating as an access and mobility function, the access and mobility in communication with at least one user equipment over a control plane, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are caused, with the at least one processor to: configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and exchange the messages via the same access type based on the configuring.

The processor caused to configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type may be further caused to: receive a new transaction identifier from a short message service function node; and define for the messages exchanged between the access and mobility function and the at least one user equipment the access type based on the transaction identifier.

The processor caused to receive a new transaction identifier from a short message service function may be further caused to receive a new transaction identifier from a short message service function for the at least one user equipment, the new transaction identifier within a Namf_Communication_N1 2MessageTransfer service operation message.

The processor may be further caused to store the new transaction identifier to use for any subsequent messages exchanged between the access and mobility function and the at least one user equipment associated with the user equipment terminated short message service are communicated via the same access type.

The processor may be further caused to: receive at the access and mobility function a request enabling reachability of the at least one user equipment from a short message service function node; and respond at the access and mobility function to the request with an access type indicator, wherein the access type indicator is used to configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type.

The transaction identifier may be based on the access type indicator.

The processor caused to configure the access and mobility function to communicate with the at least one user equipment such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type may be further caused to: receive a message transfer service operation request to forward a short message service message to the at least one user equipment; define for the messages to forward a short message service message to the at least one user equipment the access type; receive from the at least one user equipment further messages associated with the short message service message via the same access type; and forward to a short message service function an indicator identifying the access type such that further messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via the same access type.

According to a fifth aspect there is provided an apparatus for operating as an user equipment, the user equipment in communication with at least one access and mobility function over a control plane, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are caused, with the at least one processor to: configure the at least one user equipment to communicate with the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction; and exchange the messages via the same access type based on the configuring.

The processor caused to configure the user equipment to communicate with the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type may be further caused to: receive a short message service body message from the access and mobility function via a access type; and transmit any further messages from the at least one user equipment associated with the short message service body message via the access type.

According to a sixth aspect there is provided an apparatus for operating as a short message service function, the short message service function in communication with at least one access and mobility function over a control plane, the at least one access and mobility function further in communication with at least one user equipment over the control plane, the apparatus comprising at least one processor, and at least one memory including computer program code, wherein the at least one memory and the computer program code are caused, with the at least one processor to: communicate to the access and mobility function to configure the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction.

The at least one processor may be further caused to: transmit to the at least one access and mobility function a request enabling reachability of the at least one user equipment from the at least one short message service function node; and receive from the at least one access and mobility function a response to the request with an access type indicator, wherein the access type indicator, wherein the processor caused to communicate to the access and mobility function to configure the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction may be further caused to transmit the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function may select an access type to communicate messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator. The processor may be further caused to receive a short message service function an access type indicator, the access type indicator based on a determination by the access and mobility function of an access type of at least one message associated with the short message service message received at the access and mobility function from the at least one user equipment, wherein the processor caused to communicate to the access and mobility function to configure the access and mobility function such that messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service are communicated via a same access type within a short message service transaction may be further caused to transmit the access type indicator to the at least one access and mobility function node, wherein the at least one access and mobility function selects an access type to communicate messages exchanged between the access and mobility function and the at least one user equipment associated with a user equipment terminated short message service based on the access type indicator.

The processor may be further caused to transmit a transaction identifier for the at least one user equipment to the at least one access and mobility function node, the new transaction identifier being within a Namf_Communication_N1 N2MessageTransfer service operation message, and wherein the at least one access and mobility function may be configured to define for the messages exchanged between the access and mobility function and the at least one user equipment the access type based on the transaction identifier.

The transaction identifier may be the access type indicator.

The access type may comprise one of: non-access stratum via non-3GPP access; and non-access stratum via 3GPP access.

The processor caused to exchange the messages may be caused to exchange: at least one downlink non-access stratum transport message comprising a short message service body; at least one uplink non-access stratum transport message comprising a short message service acknowledgement; at least one uplink non-access stratum transport message comprising a short message service delivery report; and at least one downlink non- access stratum transport message comprising a short message service delivery report acknowledgement.

The messages may comprise short message control protocol messages.

The apparatus may comprise at least one processor and at least one memory including computer code for one or more programs.

In another aspect there is provided a computer program embodied on a non-transitory computer-readable storage medium, the computer program comprising program code for providing any of the above methods. In another aspect there is provided a computer program product for a computer, comprising software code portions for performing the steps of any of the previous methods, when said product is run.

A computer program comprising program code means adapted to perform the method(s) may be provided. The computer program may be stored and/or otherwise embodied by means of a carrier medium.

A communications system may comprise one or more of the apparatus described herein.

In the above, many different embodiments have been described. It should be appreciated that further embodiments may be provided by the combination of any two or more of the embodiments described above.

In the above, many different embodiments have been described. It should be appreciated that further embodiments may be provided by the combination of any two or more of the embodiments described above.

Description of Figures

Embodiments will now be described, by way of example only, with reference to the accompanying Figures in which:

Figure 1 shows a schematic diagram of an example communication system comprising a base station and a plurality of communication devices;

Figure 2 shows a schematic diagram of an example mobile communication device;

Figure 3 shows a schematic diagram of an example control apparatus;

Figure 4 shows an example current access procedure for mobile terminal (MT) short message service (SMS) over non-access stratum (NAS) via non-3GPP;

Figure 5 shows a first example implementation access procedure for mobile terminal (MT) short message service (SMS) over non-access stratum (NAS) via non-3GPP access procedure delivered via the same access type according to some embodiments;

Figure 6 shows a second example implementation access procedure for mobile terminal (MT) short message service (SMS) over non-access stratum (NAS) via non-3GPP access procedure delivered via the same access type according to some embodiments; and

Figure 7 shows a third example implementation access procedure for mobile terminal (MT) short message service (SMS) over non-access stratum (NAS) via non-3GPP access procedure delivered via the same access type according to some embodiments.

Detailed description Before explaining in detail the examples, certain general principles of a wireless communication system and mobile communication devices are briefly explained with reference to Figures 1 , 2 and 3 to assist in understanding the technology underlying the described examples.

In a wireless communication system 100, such as that shown in Figure 1 , mobile communication devices or user equipment (UE) 102, 104, 105 are provided wireless access via at least one base station or similar wireless transmitting and/or receiving node or point. Base stations (BTS, NodeB (NB), enhanced NodeB (eNB) are typically controlled by at least one appropriate controller apparatus, so as to enable operation thereof and management of mobile communication devices in communication with the base stations. The controller apparatus may be located in a radio access network (e.g. wireless communication system 100) or in a core network (CN) (not shown) and may be implemented as one central apparatus or its functionality may be distributed over several apparatus. The controller apparatus may be part of the base station and/or provided by a separate entity such as a Radio Network Controller (RNC). In Figure 1 control apparatus 108 and 109 are shown to control the respective macro level base stations 106 and 107. The control apparatus of a base station can be interconnected with other control entities. The control apparatus is typically provided with memory capacity and at least one data processor. The control apparatus and functions may be distributed between a plurality of control units. In some systems, the control apparatus may additionally or alternatively be provided in a radio network controller or a base station controller (BSC).

LTE systems may however be considered to have a so-called "flat" architecture, without the provision of RNCs; rather the (e)NB is in communication with a system architecture evolution gateway (SAE-GW) and a mobility management entity (MME), which entities may also be pooled meaning that a plurality of these nodes may serve a plurality (set) of (e)NBs. Each UE is served by only one MME and/or S-GW at a time and the (e)NB keeps track of current association. SAE-GW is a "high-lever user plane core network element in LTE, which may consist of the S-GW and the P-GW (serving gateway and packet data network gateway, respectively). The functionalities of the S-GW and P-GW are separated and they are not required to be co-located.

In Figure 1 base stations 106 and 107 are shown as connected to a wider communications network 1 13 via gateway 1 12. A further gateway function may be provided to connect to another network.

The smaller base stations 1 16, 1 18 and 120 may also be connected to the network 1 13, for example by a separate gateway function and/or via the controllers of the macro level stations. The base stations 1 16, 1 18 and 120 may be pico or femto level base stations or the like. In the example, stations 1 16 and 1 18 are connected via a gateway 1 1 1 whilst station 120 connects via the controller apparatus 108. In some embodiments, the smaller stations may not be provided. Smaller base stations 116, 118 and 120 may be part of a second network, for example WLAN and may be WLAN APs.

A possible mobile communication device will now be described in more detail with reference to Figure 2 showing a schematic, partially sectioned view of a communication device 200. Such a communication device is often referred to as user equipment (UE), mobile station (MS) or terminal. An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a mobile station (MS) or mobile device such as a mobile phone or what is known as a 'smart phone', a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), personal data assistant (PDA) or a tablet provided with wireless communication capabilities, an loT device or any combinations of these or the like. The term "mobile station", may also cover any such device configured for movement, e.g. a mobile loT device. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services comprise two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non- limiting examples of the content comprise downloads, television and radio programs, videos, advertisements, various alerts and other information.

The mobile device 200 may receive signals over an air or radio interface 207 via appropriate apparatus for receiving (e.g., a receiver) and may transmit signals via appropriate apparatus for transmitting radio signals (e.g., a transmitter). In Figure 2a transceiver apparatus is designated schematically by block 206. The transceiver apparatus 206 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

A mobile device is typically provided with at least one data processing entity 201 , at least one memory 202 and other possible components 203 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 204. The user may control the operation of the mobile device by means of a suitable user interface such as key pad 205, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 208, a speaker and a microphone can be also provided. Furthermore, a mobile communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

Figure 3 shows an example of a control apparatus for a communication system, for example to be coupled to and/or for controlling a station of an access system, such as a RAN node, e.g. a base station, (e)node B or 5G AP, a central unit of a cloud architecture or a node of a core network such as an MME or S-GW, a scheduling entity, or a server or host. The method may be implanted in a single control apparatus or across more than one control apparatus. The control apparatus may be integrated with or external to a node or module of a core network or RAN. In some embodiments, base stations comprise a separate control apparatus unit or module. In other embodiments, the control apparatus can be another network element such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such a control apparatus as well as a control apparatus being provided in a radio network controller. The control apparatus 300 can be arranged to provide control on communications in the service area of the system. The control apparatus 300 comprises at least one memory 310, at least one data processing unit 320, 330 and an input/output interface 340. Via the interface the control apparatus can be coupled to a receiver and a transmitter of the base station. The receiver and/or the transmitter may be implemented as a radio front end or a remote radio head. For example the control apparatus 300 or processor 320 can be configured to execute an appropriate software code to provide the control functions.

The communication devices 102, 104, 105 may access the communication system based on various access techniques, such as code division multiple access (CDMA), or wideband CDMA (WCDMA). Other non-limiting examples comprise time division multiple access (TDMA), frequency division multiple access (FDMA) and various schemes thereof such as the interleaved frequency division multiple access (IFDMA), single carrier frequency division multiple access (SC-FDMA) and orthogonal frequency division multiple access (OFDMA), space division multiple access (SDMA) and so on. Signalling mechanisms and procedures, which may enable a device to address in-device coexistence (IDC) issues caused by multiple transceivers, may be provided with help from the LTE network. The multiple transceivers may be configured for providing radio access to different radio technologies.

An example of wireless communication systems are architectures standardized by the 3rd Generation Partnership Project (3GPP). A latest 3GPP based development is often referred to as the long term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The various development stages of the 3GPP specifications are referred to as releases. More recent developments of the LTE are often referred to as LTE Advanced (LTE- A). The LTE employs a mobile network architecture known as the Evolved Universal Terrestrial Radio Access Network (E-UTRAN). Base stations or access nodes of such systems are known as evolved or enhanced Node Bs (eNBs) and provide E-UTRAN features such as user plane Packet Data Convergence/Radio Link Control/Medium Access Control/Physical layer protocol (PDCP/RLC/MAC/PHY) and control plane Radio Resource Control (RRC) protocol terminations towards the communication devices. Other examples of a radio access system comprise those provided by base stations of systems that are based on technologies such as wireless local area network (WLAN) and/or WiMax (Worldwide Interoperability for Microwave Access). A base station can provide coverage for an entire cell or similar radio service area. The Non-Access Stratum (NAS) is a set of protocols in the Evolved Packet System. The NAS is used to convey non-radio signalling between the User Equipment (UE) and the Mobility Management Entity (MME) for an LTE/E- UTRAN access.

As discussed previously the 5G core network can choose to make mobile terminated (MT) short message service (SMS) delivery over non-access stratum (NAS) via non-3GPP access in addition to 3GPP access. The MT SMS over NAS via non-3GPP access procedure can be described with respect to the access procedure as shown in Figure 4.

The current example to make mobile terminated (MT) short message service (SMS) delivery over non-access stratum (NAS) via non-3GPP access (in addition to 3GPP access) starts from the service centre (SC) 400 which communicates the message to the SMS mobile switching centre (SMS-MSC) 420.

The operation of communicating the message from the SC to the SMS-MSC is shown in Figure 4 by step 401.

The SMS-MSC 420 then interrogates the unified data management (UDM) 410 function to obtain routing information.

The operation of obtaining from the UDM the routing information for the SMS-MSC is shown in Figure 4 by step 402.

The SMS-MSC 420 may then forward the mobile terminated (MT) short message (SM) to an identified short message service function (SMSF) 430.

The operation of forwarding the SM to an identified SMSF is shown in Figure 4 by step

403.

These operations 401 to 403 follow the known operations as defined in 3GPP TS

23.040.

The SMS function (SMSF) 430 may then invoke a Namf_MT_EnableReachbility service operation request to an access and mobility management function (AMF) 440.

The operation of invoking a Namf_MT_EnableReachbility request from the SMSF 430 to the AMF is shown in Figure 4 by step 404.

The AMF 440 may then reply to the request with a response to the SMSF 430 indicating whether the user equipment (UE) 450 is registered with the network via a non-3GPP access point and the option of SMS delivery over non-3GPP access is allowed. In other words the AMF is configured to indicate to the SMSF whether the UE became reachable.

The operation of the AMF responding to the SMSF is shown in Figure 4 by step 405.

If the AMF indicates SMSF that UE is not reachable, the procedure of the unsuccessful Mobile terminating SMS delivery is performed and the following operations are skipped.

Where the AMF indicates that the UE 450 is reachable then the SMSF is configured to forward the SMS message to be sent (as defined in 3GPP TS 23.040 in other words the SMS message consists of CP DATA/RP DATA/TPDU/SMS DELIVER parts) to AMF by invoking a Namf_Communication_N1 N2MessageTransfer service operation.

The operation of invoking a message transfer service operation between the SMSF 430 and AMF 440 is shown in Figure 4 by step 406.

The AMF 440 is then configured to transfer the SMS message to the UE 450 using a downlink NAS transport message.

The operation of transferring the SMS message from the AMF to the UE is shown in Figure 4 by step 407.

The UE 450 may be configured to acknowledge receipt of the SMS message to the SMSF using an uplink NAS transport message.

The operation of using an uplink NAS transport message to acknowledge the receipt of the SMS message is shown in Figure 4 by step 408.

The AMF 440 may be further configured to invoke a Nsmsf_SMService_Up!inkSMS service operation in order to forward the acknowledgement message to the SMSF 430

The operation of forwarding the acknowledgement message from the AMF to the SMSF by invoking a Nsmsf_SMService_UplinkSMS service operation is shown in Figure 4 by step 409.

Furthermore the UE 450 is configured to return a delivery report (as defined in 3GPP TS 23.040) which is encapsulated in an uplink NAS message and sent to the AMF 440.

The operation of operation of using an uplink NAS transport message to encapsulate a delivery report is shown in Figure 4 by step 410.

The AMF 440 is further configured to forward the delivery report to the SMSF 430 by invoking a further Nsmsf_SMService_UplinkSMS service operation.

The operation of forwarding the delivery report from the AMF to the SMSF by invoking a further Nsmsf_SMService_UplinkSMS service operation is shown in Figure 4 by step 41 1 .

The SMSF 430 is configured to acknowledge receipt of the delivery report to the UE 450 by using a Namf_Communication_N1 N2MessageTransfer service operation to send a short message control protocol (SM-CP) acknowledgement (ack) message to the AMF 440.

The operation of using a Namf_Communication_N1 N2MessageTransfer service operation to send a SM-CP ack message to the AMF is shown in Figure 4 by step 413. The AMF 440 is then configured to forward this SM-CP ack message to the UE 450 using a downlink NAS transport message.

The forwarding of the forward this SM-CP ack message to the UE from the AMF is shown in Figure 4 by step 414.

In parallel to operations 413 and 4 , the SMSF 430 is configured to deliver the delivery report to the SC 400 (as defined in 3GPP TS 23.040).

If SMSF has more than one SMS to send, the SMSF and the AMF forwards subsequent SMS/SMS ack/delivery report the same way as described in the earlier operations.

When no more SMS messages are to be sent, the SMSF 430 is configured to invoke a Namf_Communication_N1 N2MessageTransfer service release request operation to terminate the SMS transaction with the AMF 440.

The operation of invoke a Namf_Communication_N1 N2MessageTransfer service release request operation to terminate the SMS transaction is shown in Figure 4 by step 415.

In this approach it is not clear whether the messages exchanged between the UE 450 and the AMF 440, for example the downlink NAS messages transporting the SMS messages and the CP acknowledgement message to the UE and the uplink NS messages transporting CP acknowledgement message and delivery report message from the UE are transported through the same access type, and if they need to be exchanged via the same access type, how it can be achieved.

The concept as discussed in further detail in the embodiments hereafter is to define that these messages should be exchanged via the same access type. In exchanging the messages via the same access type the 5G mobility management (5GMM) instance (either 3GPP 5GMM instance or non-3GPP 5GMM instance) in charge of transporting the short message control protocol (SM-CP) messages in a single procedure can be maintained. Otherwise without such a method there would be required clear criteria for dynamic access type selection. Examining such criteria for every SM-CP message transport would also be required which would bring additional complexity without achieving any clearly shown benefit.

With respect to Figures 5, 6, and 7 are shown three examples of implementing embodiments of the concept defined above of defining and implementing a system which enables all of the messages discussed between the UE and the AMF to be delivered via the same access type.

With respect to Figure 5 a first example is shown wherein a SMSF indicates a transaction identifier to the AMF, and if a new transaction identifier is received, the AMF delivers the SM-CP message via the selected access type and maintains the access type for the SM-CP delivery with respect to the same transaction identifier.

According to this example implementation to make mobile terminated (MT) short message service (SMS) delivery over non-access stratum (NAS) via non-3GPP access (in addition to 3GPP access) starts from the service centre (SC) 500 which communicates the message to the SMS mobile switching centre (SMS-MSC) 520.

The operation of communicating the message from the SC to the SMS-MSC is shown in Figure 5 by step 501.

The SMS-MSC 520 then interrogates the unified data management (UDM) 510 function to obtain routing information.

The operation of obtaining from the UDM the routing information for the SMS-MSC is shown in Figure 5 by step 502.

The SMS-MSC 520 may then forward the mobile terminated (MT) short message (SM) to an identified short message service function (SMSF) 530.

The operation of forwarding the SM to an identified SMSF is shown in Figure 5 by step

503.

These operations 501 to 503 in the same manner as operations 401 to 403 of Figure 4 follow the known operations as defined in 3GPP TS 23.040.

The SMS function (SMSF) 530 may then invoke a Namf_MT_EnableReachbility service operation request to an access and mobility management function (AMF) 540.

The operation of invoking a Namf_MT_EnableReachbility request from the SMSF to the AMF is shown in Figure 5 by step 504.

The AMF 540 may then reply to the request with a response to the SMSF 530 indicating whether the user equipment (UE) 550 is reachable for an access type, where the access type is either 3GPP access or non-3GPP access. The AMF determines the access type for which reachability is indicated taking into account the UE's registration status and other conditions. For example, the AMF may indicate the reachability of the UE over non-3GPP access if the UE is registered with the network via a non-3GPP access point and the option of SMS delivery over non-3GPP access is allowed. In other words the AMF is configured to indicate to the SMSF whether the UE became reachable.

The operation of the AMF responding to the SMSF is shown in Figure 5 by step 505.

If the AMF indicates SMSF that UE is not reachable, the procedure of the unsuccessful Mobile terminating SMS delivery is performed and the following operations are skipped.

Where the AMF indicates that the UE 550 is reachable then the SMSF is configured to forward the SMS message (as defined in 3GPP TS 23.040 in other words the SMS message consists of CP DATA/RP DATA/TPDU/SMS DELIVER parts) to AMF by invoking a Namf_Communication_N1 N2MessageTransfer service operation. A difference between this and the method shown in Figure 4 is that the SMSF 530 is configured to assign a new transaction identifier and send it to the AMF 540 for this new MT SMS delivery transaction. The newly assigned transaction identifier is included in the N20 message as a dedicated information element. In other words the identifier is sent outside the SM-CP message. The operation of invoking a message transfer service operation between the SMSF and AMF is shown in Figure 5 by step 506.

The AMF 540 is then configured to transfer the SMS message to the UE 550 via the access type determined in operations 504 and 505 if the AMF 540 receives a new transaction identifier from the SMSF for the UE. Otherwise if a transaction identifier cannot be obtained, the 3GPP access shall be chosen. The AMF 540 in some embodiments is configured to obtain the transaction identifier from a dedicated information element in the message requesting the Namf_Communication_N1 N2MessageTransfer service. The AMF 540 in these embodiments is configured to map the transaction identifier and the access type and store this mapping for a determined period. This determined period for storing the mapping between the transaction identifier and access type in some embodiments is implementation-specific.

The operation of transferring the SMS message from the AMF to the UE using the determined access type based on the received or determined transaction identifier is shown in Figure 5 by step 507.

The UE 550 may be configured to acknowledge receipt of the SMS message to the SMSF using an uplink NAS transport message using the access type through which the UE received the downlink NAS message previously.

The operation of using an uplink NAS transport message to acknowledge the receipt of the SMS message using the access type through which the UE received the downlink NAS message previously is shown in Figure 5 by step 508.

The AMF 540 may be further configured to invoke a Nsmsf_SMService_UplinkSMS service operation in order to forward the acknowledgement message to the SMSF 530

The operation of forwarding the acknowledgement message from the AMF to the SMSF by invoking a Nsmsf_SMService_UplinkSMS service operation is shown in Figure 5 by step 509.

Furthermore the UE 550 is configured to return a delivery report (as defined in 3GPP TS 23.040) which is encapsulated in an uplink NAS message using the access type through which the UE received the downlink NAS message previously (and similarly the same access type used to encapsulate the receipt acknowledgement) and sent to the AMF 540.

The operation of operation of using an uplink NAS transport message using the access type through which the UE received the downlink NAS message previously to encapsulate a delivery report is shown in Figure 5 by step 510.

The AMF 540 is further configured to forward the delivery report to the SMSF 530 by invoking a further Nsmsf_SMService_UplinkSMS service operation.

The operation of forwarding the delivery report from the AMF to the SMSF by invoking a further Nsmsf_SMService_UplinkSMS service operation is shown in Figure 5 by step 51 1 . The SMSF 530 is configured to acknowledge receipt of the delivery report to the UE 550 by using a Namf_Communication_N1 N2MessageTransfer service operation to send a SM-CP ack message to the AMF 540. The SMSF 530 is configured to include the transaction identifier assigned earlier in operation 506 in the message requesting the Namf_Communication_N1 N2MessageTransfer service. The transaction identifier is included in the N20 message as a dedicated information element.

The operation of using a Namf_Communication_N1 N2MessageTransfer service operation to send a SM-CP ack message to the AMF is shown in Figure 5 by step 513.

The AMF 540 is then configured to forward this SM-CP ack message to the UE 550 using a downlink NAS transport message through the access type that was used to deliver SMS previously. The access type in these embodiments can be derived from the transaction identifier if the AMF receives the transaction identifier for which the AMF has the mapping information towards the access type. The AMF may be configured to obtain the transaction identifier from a dedicated information element in the message requesting the Namf_Communication_N1 N2MessageTransfer service.

The forwarding of the forward this SM-CP ack message to the UE from the AMF using the access type used to deliver the SMS message previously is shown in Figure 5 by step 514. In parallel to operations 513 and 514, the SMSF 530 is configured to deliver the delivery report to the SC 500 (as defined in 3GPP TS 23.040).

If SMSF has more than one SMS to send, the SMSF and the AMF forwards subsequent SMS/SMS ack/delivery report the same way as described in the earlier operations.

When no more SMS messages are to be sent, the SMSF 530 is configured to invoke a Namf_Communication_N1 N2MessageTransfer service release request operation to terminate the SMS transaction with the AMF 540.

The operation of invoke a Namf_Communication_N1 2MessageTransfer service release request operation to terminate the SMS transaction is shown in Figure 5 by step 515.

With respect to Figure 6 a second example implementation is shown. In this example when the SMSF requests enabling UE reachability to the AMF, the AMF is configured to respond to the SMSF with the access type subject to enabling the UE reachability. The SMSF then is configured to indicate the selected access type when it requests the AMF to transport SM-CP messages in the MT SMS delivery over NAS procedure.

The second example according to some embodiments to make mobile terminated (MT) short message service (SMS) delivery over non-access stratum (NAS) via non-3GPP access (in addition to 3GPP access) starts from the service centre (SC) 600 which communicates the message to the SMS mobile switching centre (SMS-MSC) 620.

The operation of communicating the message from the SC to the SMS-MSC is shown in Figure 6 by step 601. The SMS-MSC 620 then interrogates the unified data management (UDM) 610 function to obtain routing information.

The operation of obtaining from the UDM the routing information for the SMS-MSC is shown in Figure 6 by step 602.

The SMS-MSC 620 may then forward the mobile terminated (MT) short message (SM) to an identified short message service function (SMSF) 630.

The operation of forwarding the SM to an identified SMSF is shown in Figure 6 by step

603.

These operations 601 to 603 in the same manner as operations 401 to 403 of Figure 4 follow the known operations as defined in 3GPP TS 23.040.

The SMS function (SMSF) 630 may then invoke a Namf_MT_EnableReachbility service operation request to an access and mobility management function (AMF) 640.

The operation of invoking a Namf_MT_EnableReachbility request from the SMSF 630 to the AMF is shown in Figure 6 by step 604.

The AMF 640 may then reply to the request with a response to the SMSF 630 indicating whether the user equipment (UE) 650 is reachable for an access type, where the access type is either 3GPP access or non-3GPP access. The AMF determines the access type for which reachability is indicated taking into account the UE's registration status and other conditions. For example, the AMF may indicate the reachability of the UE over non-3GPP access if the UE is registered with the network via a non-3GPP access point and the option of SMS delivery over non-3GPP access is allowed. In other words the AMF is configured to indicate to the SMSF whether the UE became reachable. In addition, the AMF 604 may also indicate to the SMSF 630 the selected access type (for example either 3GPP access or non-3GPP access). If the SMSF 630 receives the selected access type, the SMSF 630 can be configured to include the selected access type in the following N20 messages carrying the SM-CP messages.

The operation of the AMF responding to the SMSF and including a selected access type is shown in Figure 6 by step 605.

If the AMF indicates SMSF that UE is not reachable, the procedure of the unsuccessful Mobile terminating SMS delivery is performed and the following operations are skipped.

Where the AMF indicates that the UE 650 is reachable then the SMSF is configured to forward the SMS message (as defined in 3GPP TS 23.040 in other words the SMS message consists of CP DATA/RP DATA/TPDU/SMS DELIVER parts) to AMF by invoking a Namf_Communication_N1 2MessageTransfer service operation. Furthermore as discussed above the selected access type may be included in the message. In other words within the message requesting Namf_Communication_N1 2MessageTransfer service, the SMSF 630 is configured to include the access type, if the SMSF 630 has received the selected access type from the AMF 640 previously.

The operation of invoking a message transfer service operation between the SMSF 630 and AMF 640 and including the access type which was provided in step 605 is shown in Figure 6 by step 606.

The AMF 640 is then configured to transfer the SMS message to the UE 650 using a downlink NAS transport message via the access network indicator provided by the access type indicated by the SMSF 630.

The operation of transferring the SMS message from the AMF to the UE via the access network indicated by the access type indication provided by the SMSF is shown in Figure 6 by step 607.

The UE 650 may be configured to acknowledge receipt of the SMS message to the SMSF using an uplink NAS transport message. For the uplink NAS message, the UE 650 is configured to use the access type through which the UE received the downlink NAS message previously.

The operation of using an uplink NAS transport message, via the same access type through which the downlink NAS message was received, to acknowledge the receipt of the SMS message is shown in Figure 6 by step 608.

The AMF 640 may be further configured to invoke a Nsmsf_SMService_UplinkSMS service operation in order to forward the acknowledgement message to the SMSF 630

The operation of forwarding the acknowledgement message from the AMF to the SMSF by invoking a Nsmsf_SMService_UplinkSMS service operation is shown in Figure 6 by step 609.

Furthermore the UE 650 is configured to return a delivery report (as defined in 3GPP TS 23.040) which is encapsulated in an uplink NAS message using the access type through which the UE received the downlink NAS message, the uplink NAS message being sent to the AMF 640.

The operation of operation of using an uplink NAS transport message, via the same access type through which the downlink NAS message was received, to encapsulate a delivery report is shown in Figure 6 by step 610.

The AMF 640 is further configured to forward the delivery report to the SMSF 630 by invoking a further Nsmsf_SMService_UplinkSMS service operation.

The operation of forwarding the delivery report from the AMF to the SMSF by invoking a further Nsmsf_SMService_UplinkSMS service operation is shown in Figure 6 by step 61 1 .

The SMSF 630 is configured to acknowledge receipt of the delivery report to the UE 650 by using a Namf_Communication_N1 N2MessageTransfer service operation to send a SM-CP ack message to the AMF 640. In the Namf_Communication_N1 N2MessageTransfer service request message, the SMSF is configured to include the access type, if the SMSF received the selected access type from the AMF as shown previously.

The operation of using a Namf_Communication_N1 N2MessageTransfer service operation to send a SM-CP ack message to the AMF is shown in Figure 6 by step 613.

The AMF 640 is then configured to forward this SM-CP ack message to the UE 650 using a downlink NAS transport message and using the same access type indicated in the service request message.

The forwarding of the forward this SM-CP ack message to the UE from the AMF using the same access type is shown in Figure 6 by step 6 4.

In parallel to operations 613 and 614, the SMSF 630 is configured to deliver the delivery report to the SC 600 (as defined in 3GPP TS 23.040).

If the SMSF has more than one SMS to send, the SMSF and the AMF forwards subsequent SMS/SMS ack/delivery report the same way as described in the earlier operations. When no more SMS messages are to be sent, the SMSF 630 is configured to invoke a Namf_Communication_N1 N2MessageTransfer service release request operation to terminate the SMS transaction with the AMF 640.

The operation of invoke a Namf_Communication_N1 N2MessageTransfer service release request operation to terminate the SMS transaction is shown in Figure 6 by step 615.

With respect to Figure 7 a third example implementation is shown. In this example when the SMSF requests the AMF to deliver the first downlink (DL) SM-CP message for the MT SMS delivery, the SMSF is configured to indicate that the access type can be selected by the AMF. Then via the SM-CP message the UE is configured to indicate to the SMSF the selected access type. The SMSF may then be configured to indicate the access type through which the second DL SM-CP message should be delivered.

The third example implementation to make mobile terminated (MT) short message service (SMS) delivery over non-access stratum (NAS) via non-3GPP access (in addition to 3GPP access) starts from the service centre (SC) 700 which communicates the message to the SMS mobile switching centre (SMS-MSC) 720.

The operation of communicating the message from the SC to the SMS-MSC is shown in Figure 7 by step 701.

The SMS-MSC 720 then interrogates the unified data management (UDM) 710 function to obtain routing information.

The operation of obtaining from the UDM the routing information for the SMS-MSC is shown in Figure 7 by step 702.

The SMS-MSC 720 may then forward the mobile terminated (MT) short message (SM) to an identified short message service function (SMSF) 730. The operation of forwarding the SM to an identified SMSF is shown in Figure 7 by step

703.

These operations 701 to 703 in the same manner as operations 401 to 403 of Figure 4 follow the known operations as defined in 3GPP TS 23.040.

The SMS function (SMSF) 730 may then invoke a Namf_MT_EnableReachbility service operation request to an access and mobility management function (AMF) 740.

The operation of invoking a Namf_MT_EnableReachbility request from the SMSF 730 to the AMF is shown in Figure 7 by step 704.

The AMF 740 may then reply to the request with a response to the SMSF 730 indicating whether the user equipment (UE) 750 is reachable for an access type, where the access type is either 3GPP access or non-3GPP access. The AMF determines the access type for which reachability is indicated taking into account the UE's registration status and other conditions. For example, the AMF may indicate the reachability of the UE over non-3GPP access if the UE is registered with the network via a non-3GPP access point and the option of SMS delivery over non-3GPP access is allowed. In other words the AMF is configured to indicate to the SMSF whether the UE became reachable.

The operation of the AMF responding to the SMSF is shown in Figure 7 by step 705.

If the AMF indicates SMSF that UE is not reachable, the procedure of the unsuccessful Mobile terminating SMS delivery is performed and the following operations are skipped.

Where the AMF indicates that the UE 750 is reachable then the SMSF is configured to forward the SMS message (as defined in 3GPP TS 23.040 in other words the SMS message consists of CP DATA/RP DATA/TPDU/SMS DELIVER parts) to AMF by invoking a Namf_Communication_N1 N2MessageTransfer service operation. The SMSF 730 furthermore is configured to send an indication to the AMF 740. The indication lets the AMF 740 transfer the SMS message through the access type determined during the exchange between the SMSF 730 and AMF 740 establishing the reachability of the user equipment 750 as shown by operations 704 and 705. In some embodiments where an indication is not sent to the AMF 740, the AMF is configured to select a suitable 3GPP access.

The operation of invoking a message transfer service operation between the SMSF 730 and AMF 740 and either sending an indication of the access type is shown in Figure 7 by step 706.

The AMF 740 is then configured to transfer the SMS message to the UE 750 using a downlink NAS transport message via the selected 3GPP access (either selected based on the received indicator or otherwise).

The operation of transferring the SMS message from the AMF to the UE via the selected 3GPP access type is shown in Figure 7 by step 707. The UE 750 may be configured to acknowledge receipt of the SMS message to the SMSF using an uplink NAS transport message. For the uplink NAS transport message incorporating the CP-ACK message, the UE is configured to use the selected access type. In other words the access type through which the UE received the downlink NAS message comprising the SMS message. In some embodiments the CP-ACK message comprises an indication of the access type through which the UE received the SM-CP message previously.

The operation of using an uplink NAS transport message to acknowledge the receipt of the SMS message, and sending via the selected access type, is shown in Figure 7 by step 708.

The AMF 740 may be further configured to invoke a Nsmsf_SMService_UplinkSMS service operation in order to forward the acknowledgement message to the SMSF 430

The operation of forwarding the acknowledgement message from the AMF to the SMSF by invoking a Nsmsf_SMService_UplinkSMS service operation is shown in Figure 4 by step 409.

Furthermore the UE 750 is configured to return a delivery report (as defined in 3GPP TS 23.040) which is encapsulated in an uplink NAS message and sent to the AMF 740. The NAS message is transmitted by the UE via the access type through which the UE received the downlink NAS message previously (and thus which the UE used to send the uplink NAS message with the acknowledgement message previously. For the uplink NAS message delivery of the delivery report, the UE is configured to use the access type through which the UE received the downlink NAS message with the SMS body as shown in Figure 7 by step 707. The CP-ACK delivery report message in some embodiments may comprise the access type through which the UE received the downlink SM-CP message with the SMS body.

The operation of operation of using an uplink NAS transport message to encapsulate a delivery report is shown in Figure 7 by step 710.

The AMF 740 is further configured to forward the delivery report to the SMSF 730 by invoking a further Nsmsf_SMService_UplinkSMS service operation.

The operation of forwarding the delivery report from the AMF to the SMSF by invoking a further Nsmsf_SMService_UplinkSMS service operation is shown in Figure 7 by step 71 1 .

The SMSF 730 is configured to acknowledge receipt of the delivery report to the UE 750 by using a Namf_Communication_N1 N2MessageTransfer service operation to send a SM-CP ack message to the AMF 740. The SMSF 730 furthermore is configured to indicate the access type that the SMSF received from the UE via the CP-ACK message either from the message acknowledgement message or the delivery report message.

The operation of using a Namf_Communication_N 1 N2MessageTransfer service operation to send a SM-CP ack message to the AMF is shown in Figure 7 by step 713. The A F 740 is then configured to forward this SM-CP ack message to the UE 750 using a downlink NAS transport message and through the access type indicated by the SMSF.

The forwarding of the forward this SM-CP ack message to the UE from the AMF through the access type indicated by the SMSF is shown in Figure 7 by step 714.

In parallel to operations 713 and 714, the SMSF 730 is configured to deliver the delivery report to the SC 700 (as defined in 3GPP TS 23.040).

If SMSF has more than one SMS to send, the SMSF and the AMF forwards subsequent SMS/SMS ack/delivery report the same way as described in the earlier operations.

When no more SMS messages are to be sent, the SMSF 730 is configured to invoke a Namf_Communication_N1 N2MessageTransfer service release request operation to terminate the SMS transaction with the AMF 740.

The operation of invoke a Namf_Communication_N1 N2MessageTransfer service release request operation to terminate the SMS transaction is shown in Figure 7 by step 715.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The embodiments of this invention may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and/or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computer- executable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it.

Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples.

Embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.