Signalling for group communications

1. An apparatus configured to schedule both a device-to-device (D2D) transmission and D2D reception of data between nodes of a scheduling group using a single resource allocation grant, the apparatus comprising:

at least one processor; and

at least one memory including computer program code,

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

reserve resources for a device-to-device-(D2D) communication between a set of nodes organized into one or more scheduling groups having a predetermined group identity, each node in a scheduling group having an unique identity;

transmit a scheduling message to each of the one or more scheduling groups, each of the scheduling messages providing a single resource allocation grant for both D2D transmission and reception of data between nodes of the scheduling group, each scheduling message comprising the group identity that identifies the scheduling group for which the scheduling message is intended, an information element identifying a node within the scheduling group that is allowed to transmit data via D2D communication to other nodes in the group using the allocated resources, a bitmap identifying nodes within the scheduling group that are instructed to receive the data via D2D communication using the allocated resources, and information on parameters needed to transmit and receive the data using the allocated resources.

2. The apparatus of claim 1 , further configured to determine the size of the bitmap on the basis of the number of the nodes in the scheduling group.

3. The apparatus of claim 1 , wherein the group identity is a predefined cell radio network temporary identifier.

4. The apparatus of claim 1 , further configured to:

reserve communication resources for nodes belonging to different scheduling groups; and

transmit scheduling messages with group identities of all scheduling groups the communicating nodes belong to.

5. The apparatus of claim 1 , further configured to organize the set of nodes into one or more scheduling groups on the basis of at least one of a location of each node, a path loss experienced by each node, and a service needed by each node.

6. The apparatus of claim 1 , further configured to transmit scheduling messages on a predefined control channel search space common to all nodes in a group.

7. The apparatus of claim 1 , wherein group identity is used as physical layer error protection for the group of nodes and where the information element indicating identity of the node allowed to transmit and the bitmap indicating identities of nodes instructed to receive are included in a payload of a control signaling message.

8. The apparatus of claim 1 , wherein a predefined code word of the information element indicating identity of the node allowed to transmit indicates a broadcast case where the apparatus is transmitting.

9. The apparatus of claim 1 , wherein group grant transmission (Tx) is prioritized in the case a node has valid Tx grant received via dedicated identity and group identity.

10. A method of scheduling both a device-to-device (D2D) transmission and D2D reception of data between nodes of a scheduling group using a single resource allocation grant, the method comprising:

reserving resources for a device-to-device communication between a set of nodes organized into one or more scheduling groups having a predetermined group identity, each node in a scheduling group having an unique identity;

transmitting a scheduling message to each of the one or more scheduling groups, each of the scheduling messages providing a single resource allocation grant for both D2D transmission and reception of data between nodes of the scheduling group, each scheduling message comprising the group identity that identifies the scheduling group for which the scheduling message is intended, an information element identifying a node within the scheduling group that is allowed to transmit data via D2D communication to other nodes in the group using the allocated resources, a bitmap identifying nodes within the scheduling group that are instructed to receive the data via D2D communication using the allocated resources, and information on parameters needed to transmit and receive the data using the allocated resources.

11. The method of claim 10 , further comprising: determining the size of the bitmap on the basis of the number of the nodes in the scheduling group.

12. The method of claim 10 , wherein the group identity is a predefined cell radio network temporary identifier.

13. The method of claim 12 , further comprising:

detecting the unique identity in an information element of the message indicating that the apparatus is allowed to transmit;

detecting in the message the resources and transmission parameters to be used; and

initiating group based transmission using the resources.

14. The method of claim 10 , further comprising:

reserving communication resources for nodes belonging to different scheduling groups; and

transmitting scheduling messages with group identities of all scheduling groups the communicating nodes belong to.

15. A computer program product embodied on a non-transitory computer-readable medium and comprising program instructions which, when loaded into an apparatus, execute the method according to claim 10 .

16. A method comprising:

receiving, by a node that is part of one or more scheduling groups within a wireless network, a scheduling message for one or more scheduling groups, each of the scheduling messages providing a single resource allocation grant for both device-to-device (D2D) transmission and reception of data between nodes of the scheduling group, each scheduling message comprising the group identity that identifies the scheduling group for which the scheduling message is intended, an information element identifying a node within the scheduling group that is allowed to transmit data via D2D communication to other nodes in the group using the allocated resources, a bitmap identifying nodes within the scheduling group that are instructed to receive the data via D2D communication using the allocated resources, and information on parameters needed to transmit and receive the data using the allocated resources.

17. The method of claim 16 and further comprising:

determining, by the node, that the scheduling message has identified that the node is allowed to transmit to other nodes within the group using the allocated resources; and

transmitting, by the node, data to other nodes within the group via D2D communication using the allocated resources.

18. The method of claim 16 and further comprising:

determining, by the node, that the scheduling message has instructed the node to receive the data; and

receiving, by the node, the data via D2D communication using the allocated resources.