Concurrent multi-level broadcast and unicast for small unmanned aerial vehicles and V2X systems

1. A wireless transmit/receive unit (WTRU) configured to:

determine a first group network temporary identifier (GRNTI) wherein the first GRNTI is associated with a broadcast transmission from an eNodeB to a plurality of WTRUs;

determine a second GRNTI, wherein the second GRNTI is associated with a transmission from the eNodeB to a subset of the plurality of WTRUs that received the first GRNTI;

receive a multi-level transmission, wherein the multi-level transmission comprises a first level message and a second level message that are sent on a common set of resources using superposition coding;

decode the first level message from the multi-level transmission using the first GRNTI and preconfigured control information; and

decode the second level message from the multi-level transmission using the second GRNTI, if the first level message was configured for the WTRU.

2. The WTRU of claim 1 , wherein the first GRNTI is indicated using system information.

3. The WTRU of claim 1 , wherein the second GRNTI is indicated using a dedicated configuration.

4. The WTRU of claim 1 , wherein the WTRU is further configured to cancel the first level message from the multi-level transmission in order to receive the second level message, and using the preconfigured control information from the first level message to decode the second level message.

5. The WTRU of claim 1 , wherein the second level message is at least one of a multicast message, a unicast message, and a re-transmission of a message after an error in that message.

6. The WTRU of claim 1 , wherein the multi-level transmission is received in accordance with a semi-persistent configuration, and wherein instances of the multi-level transmission are sent using a periodicity defined by the semi-persistent configuration.

7. The WTRU of claim 6 , wherein the multi-level transmission includes a bitmap related to the interval allocated for superposition coding.

8. The WTRU of claim 1 , wherein the WTRU is an unmanned aerial vehicle (UAV).

9. The WTRU of claim 8 , wherein the first level message is an Automatic Dependent Surveillance-Broadcast (ADS-B).

10. The WTRU of claim 8 , wherein the subset of the plurality of WTRUs are in a common geographical vicinity or are using a common application.

11. The WTRU of claim 1 , wherein the first level message corresponds to a broadcast message, the second level message corresponds to a multicast message, and the WTRU is further configured to:

determine a WTRU-specific RNTI, wherein the WTRU-specific RNTI is associated with a unicast transmission to the WTRU, wherein the multi-level transmission further comprises a third level message that is sent on the common set of resources with the first level-message and the second-level message using superposition coding; and

decode the third level message from the multi-level transmission using the WTRU-specific RNTI.

12. The WTRU of claim 11 , wherein the WTRU is further configured to cancel the first and second level messages from the multi-level transmission in order to decode the third level message.

13. A method of processing a multi-level transmission sent on a common set of resources using superposition coding, comprising:

determining a first group radio network temporary identifier (GRNTI), wherein the GRNTI is associated with a broadcast transmission from an eNodeB to a plurality of wireless transmit/receive units (WTRUs);

determining a second GRNTI, wherein the second GRNTI is associated with a transmission from the eNodeB to a subset of the plurality of WTRUs that received the first GRNTI;

receiving the multi-level transmission, wherein the multi-level transmission comprises a first level message and a second level message;

decoding the first level message from the multi-level transmission using the first GRNTI and preconfigured control information; and

decoding the second level message from the multi-level transmission using the second GRNTI, if the first level message was configured for the WTRU.

14. The method of claim 13 , wherein the WTRU decodes the second level message after the first message and first GRNTI is configured for the WTRU.

15. The method of claim 13 , wherein the multi-level transmission is received in accordance with a semi-persistent configuration, and wherein instances of the transmission are sent using a periodicity defined by the semi-persistent configuration.

16. The method of claim 15 , wherein the multi-level transmission is received and includes a bitmap related to the interval allocated for superposition coding.

17. The method of claim 13 , wherein the common set of resources used for transmission of the multi-layer message are defined by a semi-persistent configuration received by one or more of the WTRUs.

18. The method of claim 13 , wherein the WTRUs are unmanned aerial vehicles (UAVs) and the first level message is an Automatic Dependent Surveillance-Broadcast (ADS-B).

19. The method of claim 18 , wherein the subset of the plurality of WTRUs are in a common geographical vicinity, and the common geographical vicinity comprises a common altitude range.

20. The method of claim 13 , wherein the decoding of the second level message from the multi-level transmission is conditioned on the successful decoding the first level message from the multi-level transmission.