Creating a pseudonym for requesting a network slice

1. A method performed by a communication device for requesting use of a network slice from a network, the method comprising:

receiving a message transmitted by a network node in the network, the message comprising a set of network slice identifiers, wherein each network slice identifier identifies a different network slice, and the message conveys information for enabling the communication device to obtain, for each identified network slice, a network slice pseudonym for the network slice, wherein the network slice pseudonym for the network slice is different than the network slice identifier that identifies the network slice;

selecting a first network slice from the set of identified network slices;

using the information conveyed by the message to obtain a first network slice pseudonym for use in identifying the selected first network slice; and

transmitting a request message to the network, wherein the request message comprises the first network slice pseudonym.

2. The method of claim 1 , wherein the message further comprises information for generating a slice pseudonym for each identified network slice.

3. The method of claim 1 , wherein the message further comprises, for each identified network slice, a slice pseudonym for identifying the network slice.

4. The method of claim 3 , wherein

each slice pseudonym is specific to the wireless device.

5. The method of claim 1 , wherein

the message further comprises, for each identified network slice, a slice number associated with the identified network slice, and

using the information conveyed by the message to obtain the first network slice pseudonym for use in identifying the selected first network slice comprises:

selecting a number between the slice number associated with said selected network slice and an adjacent slice number; and

using the selected number as the first network slice pseudonym.

6. The method of claim 1 , wherein the set of network slice identifiers is an ordered set of network slice identifiers and the position of each network slice identifier in the ordered set conveys the information enabling the communication device to obtain, for each identified network slice, a network slice pseudonym for the network slice.

7. The method of claim 6 , wherein using the information conveyed by the message to obtain the first network slice pseudonym for use in identifying the selected first network slice comprises calculating:

sp=p +( r×L ), where

sp represents the first network slice pseudonym,

p is the position, within the ordered set of network slice identifiers, of the network slice identifier that identifies the selected network slice,

r is a selected whole number greater than or equal to zero, and

L is the total number of network slice identifies in the ordered set of network slice identifiers.

8. The method of claim 7 , further comprising randomly selecting r.

9. The method of claim 1 , wherein the network node is in a home network of the wireless device.

10. The method of claim 1 , wherein a network slice is represented by Single Network Slice Selection Assistance Information (S-NSSAI) and said request message is a NSSAI-NAS request (Requested NSSAI-NAS) or a NSSAI-RRC request (Requested NSSAI-RRC).

11. The method of claim 1 , wherein the step of selecting the network slice is performed after the step of receiving the message.

12. The method of claim 1 , further comprising

selecting a second network slice from the set of identified network slices; and

using the information conveyed by the message to obtain a second network slice pseudonym for use in identifying the selected second network slice, wherein

the request message further comprises the second network slice pseudonym.

13. The method of claim 1 , wherein

the message further comprises, for each identified network slice, a slice number associated with the identified network slice, and

obtaining the first network slice pseudonym for use in identifying the selected first network slice comprises obtaining a number using the slice number associated with said selected network slice, wherein

the obtained number is used as the first network slice pseudonym.

14. A method performed by a network node, for allocating a network slice to a communication device, the method comprising:

transmitting a message to the communication device, the message comprising a set of network slice identifiers, wherein each network slice identifier identifies a different network slice, and the message conveys information for enabling the communication device to obtain, for each identified network slice, a network slice pseudonym for the network slice, wherein the network slice pseudonym for the network slice is different than the network slice identifier that identifies the network slice;

receiving a request message relating to a request sent by a wireless device, wherein the request message comprises a first network slice pseudonym;

identifying a first requested network slice from the first network slice pseudonym; and

permitting use of the requested network slice.

15. The method of claim 14 , wherein the message further comprises, for each identified network slice, a slice pseudonym for identifying the network slice.

16. The method of claim 14 , wherein

the set of network slice identifiers is an ordered set of network slice identifiers and the position of each network slice identifier in the ordered set conveys the information enabling the communication device to obtain, for each identified network slice, a network slice pseudonym for the network slice.

17. The method of claim 14 , wherein

the message further comprises, for each identified network slice, a slice number associated with the identified network slice, and

identifying the first requested network slice from the first network slice pseudonym comprises:

mapping the first network slice pseudonym to one of the slice numbers; and

using the slice number to which the first network slice pseudonym is mapped to identify the first requested network slice.

18. The method of claim 14 , wherein

the set of network slice identifiers is an ordered set of network slice identifiers and the position of each network slice identifier in the ordered set conveys the information enabling the communication device to obtain, for each identified network slice, a network slice pseudonym for the network slice.

19. The method of claim 14 , performed in a home network of the wireless device, the method comprising:

receiving said request message from a network that is being visited by the wireless device;

identifying the requested network slice to the visited network; and

providing the visited network with the or each requested network slice.

20. The method of claim 14 , wherein identifying the first requested network slice from the first network slice pseudonym comprises:

calculating X=P modulo len(S); and

using X to identify the first request network slice, where

P is the first network slice pseudonym, and

len(S) is the number of network slice identifiers included in the set of network slice identifiers.

21. A wireless device, the wireless device comprising:

processing circuitry configured to perform the steps of claim 1 ; and

power supply circuitry configured to supply power to the wireless device.

22. The wireless device of claim 21 , wherein at least some of said steps are performed in a Mobile Equipment part of the wireless device.

23. The wireless device of claim 21 , wherein at least some of said steps are performed in a Universal Integrated Circuit Card part of the wireless device.

24. A network node, the network node comprising:

processing circuitry configured to perform the steps of claim 14 ; and

power supply circuitry configured to supply power to the network node.