Method of providing information on device-to-device resources, cellular network node and user equipment

1. A method of providing information on resources for a device-to-device discovery and/or a device-to-device communication, the method comprising: performing, in a network node, a comparison of device-to-device resources for a cell and further device-to-device resources for at least one further cell different from the cell to determine whether the device-to-device resources of the cell are offset from the further device-to-device resources of the at least one further cell along time and frequency, and generating at least one information element of a message for transmission to a user equipment based on a result of the comparison, wherein performing the comparison comprises: comparing a pattern of the device-to-device resources in a time-frequency resource grid and a further pattern of the further device-to-device resources in the time-frequency resource grid; and

at least one of determining whether the pattern and the further pattern are identical or determining whether the further pattern is shifted in the time-frequency resource grid relative to the pattern.

2. The method of claim 1 ,

wherein the at least one information element comprises information on a time offset and/or a frequency offset between the pattern and the further pattern.

3. The method of claim 2 ,

wherein the time offset and/or the frequency offset is determined with reference to a serving cell.

4. The method of claim 1 ,

wherein performing the comparison comprises:

determining whether a frame timing of the cell and a frame timing of the at least one further cell are aligned.

5. The method of claim 4 ,

wherein the at least one information element comprises information on a time offset between the frame timing of the cell and the frame timing of the at least one further cell.

6. The method of claim 4 ,

wherein the at least one information element is generated such that it includes a type identifier which defines

whether the further pattern is identical to the pattern or shifted in the time-frequency resource grid relative to the pattern, and

whether the frame timing of the cell and the frame timing of the at least one further cell are aligned.

7. The method of claim 1 , further comprising:

selecting, in dependence on a result of the comparison, the at least one further cell to provide the user equipment with information on the further device-to-device resources.

8. The method of claim 1 ,

wherein information on the further device-to-device resources is selectively included in the message only if the comparison shows that the further device-to-device resources are not derivable from the device-to-device resources.

9. The method of claim 1 ,

wherein the at least one information element defines an offset in a time-frequency resource grid with reference to a serving cell.

10. The method of claim 1 , further comprising:

receiving, from the user equipment, a request for additional information on the further device-to-device resources in response to transmitting the message to the user equipment, and

generating a further message for transmission to the user equipment which includes the additional information.

11. The method of claim 10 ,

wherein the request identifies frequencies of the further device-to-device resources and/or a public land mobile network in which the user equipment is interested.

12. The method of claim 1 ,

wherein the message is generated to include information on the device-to-device resources for the cell, and

wherein the method further comprises:

determining, by the user equipment, the further device-to-device resources from the information on the device-to-device resources and the at least one information element included in the message.

13. The method of claim 12 ,

wherein determining the further device-to-device resources comprises:

determining, by the user equipment, a time offset and/or a frequency offset between the device-to-device resources and the further device-to-device resources based on the at least one information element.

14. The method of claim 1 , further comprising:

performing, by the user equipment, a device-to-device discovery using resources determined based on the at least one information element to discover a further user equipment attached to a cell or public land mobile network different from the cell or public land mobile network to which the user equipment is attached.

15. A cellular network node, comprising: a processing device configured to: perform in the network node a comparison of device-to-device resources for a cell and further device-to-device resources for at least one further cell different from the cell to determine whether the device-to-device resources of the cell are offset from the further device-to-device resources of the at least one further cell along time and frequency,

wherein the processing device is configured to perform the comparison by comparing a pattern of the device-to-device resources in a time-frequency resource grid and a further pattern on the further device-to-device resources in the time-frequency resource grid; determining at least one of whether the pattern and the further pattern are identical or whether the further pattern is shifted in the time-frequency resource grid relative to the pattern, and generate at least one information element of a message for transmission to a user equipment based on a result of the comparison; and an interface configured to output the at least one information element for transmission to the user equipment.

16. The cellular network node of claim 15 ,

wherein the processing device is operative to determine whether a pattern of the device-to-device resources in a time-frequency resource grid and a further pattern of the further device-to-device resources in the time-frequency resource grid are identical.

17. The cellular network node of claim 15 ,

wherein the processing device is operative to determine whether a pattern of the device-to-device resources in a time-frequency resource grid and a further pattern of the further device-to-device resources in the time-frequency resource grid are shifted in the time-frequency resource grid.

18. The cellular network node of claim 15 ,

wherein the processing device is operative to generate the at least one information element such that it indicates

whether a pattern of the device-to-device resources in a time-frequency resource grid and a further pattern of the further device-to-device resources in the time-frequency resource grid are identical or shifted in the time-frequency resource grid, and

whether a frame timing of the cell and a frame timing of the at least one further cell are aligned.

19. The cellular network node of claim 15 ,

wherein the cellular network node is operative to selectively provide information on the further device-to-device resources for transmission to the user equipment if the further device-to-device resources are not derivable from the device-to-device resources.

20. A user equipment, comprising:

a wireless interface configured for communication with a cellular communication network; and

a processing device configured to control the wireless interface to perform a device-to-device discovery and/or a device-to-device communication with a further user equipment,

the processing device being configured to process a message received from the cellular communication network at the wireless interface that identifies whether device-to-device resources of a cell are offset from further device-to-device resources of at least one further cell along time and frequency to determine which further device-to-device resources are used by a further user equipment for the device-to-device discovery and/or a device-to-device communication, the further user equipment being located in a further cell different from the cell in which the user equipment is located

wherein the message comprises at least one information element which indicates whether a pattern of the device-to-device resources in a time-frequency-resource grid is identical to a pattern of the further device-to-device resources in the time-frequency-resource grid, or at least one information element which indicates whether a pattern of the device-to-device resources in a time-frequency-resource grid is shifted in the time-frequency-resource grid relative to a pattern of the further device-to-device resources in the time-frequency-resource grid.

21. The user equipment of claim 20 ,

wherein the processing device is configured to detect device-to-device discovery signals transmitted by the further user equipment at the further device-to-device resources based on the message received from the cellular communication network.

22. The user equipment of claim 20 ,

wherein the message comprises at least one information element which indicates

whether a pattern of the device-to-device resources in a time-frequency resource grid and a further pattern of the further device-to-device resources in the time-frequency resource grid are identical or shifted in the time-frequency resource grid, and

whether a frame timing of the cell and a frame timing of the at least one further cell are aligned.

23. The user equipment of claim 20 ,

wherein information on the further device-to-device resources are included in the message if the further device-to-device resources are not derivable from the device-to-device resources.