Network controlled device to device / machine to machine cluster operation

1. A method, comprising:

assigning a cluster-specific device to device cluster cell radio network identifier to a cluster;

determining uplink resources to be granted to a cluster;

preparing, at an apparatus, an uplink resource grant for the cluster, based on the determining, by re-using an existing uplink resource grant message and apply the assigned cluster-specific device to device cluster cell radio network identifier, wherein the prepared uplink resource grant includes a transmitter identifier; and

transmitting the uplink resources grant to a plurality of cluster nodes of the cluster, wherein the transmitter identifier identifies at least one node of the plurality of cluster nodes.

2. The method of claim 1 , wherein the cluster comprises at least one group and each of the at least one group comprises at least one node, the method further comprising:

assigning transmitter identifiers and group identifiers for cluster members.

3. The method of claim 1 , wherein the preparing the uplink resource grant comprises replacing an existing field of the e existing uplink resource grant message by the transmitter identifier and a group identifier.

4. The method of claim 1 , wherein the preparing the uplink resource grant comprises replacing an existing field of the existing uplink resource grant message by an uplink/downlink configuration information.

5. The method of claim 1 , wherein the preparing the uplink resource grant comprises replacing an existing field of the existing uplink resource grant message by a multicast indication in the uplink resources grant.

6. An apparatus, comprising:

at least one memory including computer program code; and

at least one processor,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to

assign a cluster-specific device to device cluster cell radio network identifier to a cluster;

determine uplink resources to be granted to a cluster;

prepare an uplink resource grant for the cluster, based on the determining, by re-using an existing uplink resource grant message and applying the assigned cluster-specific device to device cluster cell radio network identifier, wherein the prepared uplink resource grant includes a transmitter identifier; and

transmit the uplink resources grant to a plurality of cluster nodes of the cluster, wherein the transmitter identifier identifies at least one node of the plurality of cluster nodes.

7. The apparatus of claim 6 , wherein the cluster comprises at least one group and each of the at least one group comprises at least one node, wherein the at least one memory and the computer program code are also configured to, with the at least one processor, cause the apparatus at least to assign transmitter identifiers and group identifiers for cluster members.

8. The apparatus of claim 6 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to prepare the uplink resource grant by replacing an existing field of the existing uplink resource grant message by the transmitter identifier and a group identifier.

9. The apparatus of claim 6 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to replace an existing field of the existing uplink resource grant message by an uplink/downlink configuration information.

10. The apparatus of claim 6 , wherein the at least one memory and the computer program code are further configured to, with the at least one processor, cause the apparatus at least to replace an existing field of the existing uplink resource grant message by a multicast indication in the uplink resources grant.

11. A method, comprising:

receiving, at an apparatus, a cluster-specific device to device cluster cell radio network identifier;

receiving an uplink resource grant message for a cluster;

decoding the uplink resource grant message by applying the received cluster-specific device to device cluster cell radio network identifier;

if the uplink resource grant message is successfully decoded, re-interpreting the received uplink resource grant message to obtain a transmitter identifier carried in the uplink resource grant message; and

checking the transmitter identifier to determine whether it corresponds to the apparatus.

12. The method of claim 11 , wherein the cluster comprises at least one group and each of the at least one group comprises at least one node, the method further comprising:

re-interpreting the received uplink resource grant message to obtain a group identifier carried in the uplink resource grant message.

13. The method of claim 11 , further comprising:

re-interpreting the received uplink resource grant message to obtain an uplink/downlink configuration information carried in the uplink resource grant message.

14. The method of claim 11 , further comprising:

re-interpreting the received uplink resource grant message to obtain a multicast indication carried in the uplink resource grant message.

15. The method of claim 11 , further comprising,

when the determination is that the transmitter identifier corresponds to the apparatus, preparing a frame for transmission based on the uplink resources grant, otherwise,

switching the apparatus to reception mode, or listening for device to device control channel information.

16. An apparatus, comprising:

at least one memory including computer program code; and

at least one processor,

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to

receive a cluster-specific device to device cluster cell radio network identifier;

receive an uplink resource grant message for a cluster;

decode the uplink resource grant message by applying the received cluster-specific device to device cluster cell radio network identifier;

if the uplink resource grant message is successfully decoded, re-interpret the received uplink resource grant message to obtain a transmitter identifier carried in the uplink resource grant message; and

check the transmitter identifier to determine whether it corresponds to the apparatus.

17. The apparatus of claim 16 , wherein the cluster comprises at least one group and each of the at least one group comprises at least one node, and wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to re-interpret the received uplink resource grant message to obtain a group identifier carried in the uplink resource grant message.

18. The apparatus of claim 16 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to re-interpret the received uplink resource grant message to obtain an uplink/downlink configuration information carried in the uplink resource grant message.

19. The apparatus of claim 16 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to re-interpret the received uplink resource grant message to obtain a multicast indication carried in the uplink resource grant message.

20. The apparatus of claim 16 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus at least to, when the determination is that the transmitter identifier corresponds to the apparatus, prepare a frame for transmission based on the uplink resources grant, otherwise to switch the apparatus to reception mode or to listen for device to device control channel information.