EFFICIENT CONTENTION BASED DECENTRALIZED PROCEDURE FOR DEVICE TO DEVICE COMMUNICATION

1 . A method for enhancing contention-based device to device (D2D) resource allocation, wherein resources are allocated on a non-user device specific basis, the method comprising:

initiating communication, by a first user device, a resource request message (RR) to a second user device;

receiving, by the first user device from the second user device and in response to the resource request message, an acknowledge to transmit message (AT); and

in response to receiving the AT, initiating a first data communication session, by the first user device, between the first user device and the second user device.

2 . The method of claim 1 ,

wherein the first user device does not have a dedicated resource for D2D communication.

3 . The method of claim 2 ,

wherein the first user device is located in an in-coverage region and an eNB or group head for the in-coverage region is not configured to manage some or all D2D resources.

4 . The method of claim 2 ,

wherein the first user device is located in a decentralized region wherein no eNB or group head exists to manage D2D resource allocation.

5 . The method of claim 4 ,

wherein the RR comprises a sender/receiver ID, data size information, pointer of a resource block (RB), duration of communication information, and service type information;

wherein the AT comprises a sender/receiver ID, data size information, pointer of an RB, duration of communication information, and service type information; and

wherein RR and AT resource block locations are associated with predetermined fixed time or frequency offsets.

6 . The method of claim 1 , further comprising:

determining a packet size;

comparing the determined packet size with a predetermined threshold;

when packet size is greater than the predetermined threshold, determining that RR/AT transmission should be used;

when packet size is less than the predetermined threshold, determining that non-RR/AT transmission should be used; and

initiating a second data communication session, by the first user device with a third user device, based on the comparison.

7 . The method of claim 1 , further comprising:

dividing and dedicating a total number of available D2D resources into a RR/AT portion and a non-RR/AT portion;

monitoring, by the first user device, the RR/AT portion of the resources and the non-RR/AT portion of the resources to determine; and

in response to detecting a communication on the RR/AT portion of the resources or the non-RR/AT portion of the resources, performing, by the first user device, one or more corresponding actions or entering one or more corresponding modes.

8 . The method of claim 1 , further comprising:

receiving, by the second user device, a second RR message sent by a third user device;

determining, by the second user device, whether the second RR message and the RR message received from the first user device are in conflict; and

in response to determining the RR message and the second RR message are not in conflict, initiating communication of a second AT message to the third user device.

9 . The method of claim 1 , further comprising:

initiating communication, by the first user device, a second resource request message (RR) to a third user device, wherein the second RR message is not in conflict with the RR message;

receiving, by the first user device from the third user device and in response to the second RR message, a second AT message; and

in response to receiving the second AT message, initiating a second data communication session, by the first user device, between the first user device and the third user device.

10 . The method of claim 1 , further comprising:

selecting, by the first user device, at least one of a plurality of resources comprising a timing offset, frequency offset, resource block (RB) and/or carrier for communication of the RR message; and

wherein initiating communication of the RR message comprises initiating communication based at least in part on the selected at least one resource.

11 . The method of claim 10 , further comprising:

monitoring, by the second user device, all resources across time, frequency and/or carriers to determine whether any RR or AT is present.

12 . The method of claim 10 ,

wherein selecting the at least one resource comprises randomly selecting at least one unused resource from the plurality of resources; and

wherein the RR message has a resource location and the AT message has a resource location that is a predetermined offset from the RR message resource location.

13 . The method of claim 1 , further comprising:

randomly selecting, by the first user device, at least one of a plurality of resources comprising a timing offset, frequency offset, resource block (RB) and/or carrier for initiating a non-RR/AT data communication session, wherein the data to be transmitted has a size less than a predetermined packet size limit and the selected resource has a data size greater than or equal to the size of the data to be transmitted; and

initiating a non-RR/AT data communication session based at least in part on the randomly selected at least one resource.

14 . The method of claim 1 , further comprising:

selecting, by the first user device, at least one of a plurality of resources comprising a timing offset, frequency offset, resource block (RB) and/or carrier for communication of the RR message, wherein selecting is based at least in part on one or more alignment parameters for aligning resource contention among multiple user devices; and

wherein initiating communication of the RR message comprises initiating communication based at least in part on the selected at least one resource.

15 . The method of claim 1 , further comprising:

selecting, by the first user device, at least one of a plurality of resources comprising a timing offset, frequency offset, resource block (RB) and/or carrier for initiating a non-RR/AT data communication session, wherein selecting is based at least in part on one or more alignment parameters for aligning resource contention among multiple user devices; and

initiating a non-RR/AT data communication session based at least in part on the selected at least one resource.

16 . The method of claim 15 , wherein the alignment parameters dictate that non-RR/AT data communication sessions should be placed with a resource unallocated by any RR/AT communication.

17 . The method of claim 15 , wherein the alignment parameters dictate that non-RR/AT data communication sessions should be placed with a predetermined time, frequency and/or carrier slot of a resource.

18 . The method of claim 14 , wherein the alignment parameters dictate that RR/AT messages and RR/AT data communication sessions should be placed with a first and second predetermined time, frequency and/or carrier slot, respectively, of a resource.

19 . The method of claim 14 , further comprising:

monitoring, by the first user device, all resources allocated for AT messages, based at least in part on the alignment parameters; and

determining, by the first user device, the RR/AT data communication session should be placed with a next available time, frequency and/or carrier slot of a resource based at least in part on a plurality of indexed RR/AT resources.

20 . The method of claim 1 ,

wherein the RR and AT messages are communicated over a first shared resource having a first location, the method further comprising:

determining a second location of a second shared resource based on the first location and based on at least one predetermined linking parameter, wherein the second shared resource has a second resource block size and the first data communication session is placed on the second shared resource at the second location;

initiating a second data communication session placed on a third shared resource at a third location having a third resource block size;

wherein the third resource block size is different than the second resource block size.

21 . The method of claim 1 ,

wherein the RR and AT messages indicate a traffic type associated with the communication data session, the method further comprising:

determining a resource allocation based at least in part on the traffic type.

22 . The method of claim 1 ,

wherein the second user device is a group head for a plurality of group user devices, the method further comprising:

forwarding and/or broadcasting the first data communication session, by the second communication device to the plurality of group user devices

23 . An apparatus for enhancing contention-based device to device (D2D) resource allocation, wherein resources are allocated on a non-user device specific basis, the apparatus comprising:

a memory;

a processor; and

a module stored in the memory, executable by the processor, and configured to:

initiate communication a resource request message (RR) to a second apparatus;

receive, from the second apparatus and in response to the resource request message, an acknowledge to transmit message (AT); and

in response to receiving the AT, initiate a first data communication session between the apparatus and the second apparatus.

24 . A computer program product for enhancing contention-based device to device (D2D) resource allocation, wherein resources are allocated on a non-user device specific basis, the computer program product comprising:

a non-transitory computer-readable medium comprising a set of codes for causing a computer to:

initiate communication a resource request message (RR) to a second apparatus;

receive, from the second apparatus and in response to the resource request message, an acknowledge to transmit message (AT); and

in response to receiving the AT, initiate a first data communication session between the apparatus and the second apparatus.