Methods to enable high data rate relay operation using D2D air-interface

1. A User Equipment (UE) for transmitting and receiving data via a sidelink interface under control of an Evolved Node B (eNB), the UE comprising:

receive circuitry to receive a reference signal on a sidelink interface;

control circuitry to determine one or more sidelink quality indicators based on the received reference signal; and

transmit circuitry to transmit the determined sidelink quality indicators to the eNB, wherein the receive circuitry is further to:

receive a first indication, via a downlink control channel from the eNB, of first radio resources on the sidelink interface to be used for receiving first data;

receive the first data on the sidelink interface based on the indication of first radio resources;

receive a second indication, via a sidelink control channel, of second radio resources on the sidelink interface to be used for receiving second data; and

receive the second data on the sidelink interface based on the second indication of second radio resources,

wherein the UE is a remote UE that is to receive data from and transmit data to the eNB via a relay path using the sidelink interface.

2. The UE of claim 1 , wherein the sidelink quality indicators comprise: sidelink Reference Signal Received Power (sidelink RSRP) indicators; sidelink Reference Signal Received Quality (sidelink RSRQ) indicators; or sidelink Reference Signal Strength Indicator (sidelink RSSI) indicators.

3. The UE of claim 1 , the transmit circuitry further to transmit the reference signal on the sidelink interface to at least one Relay UE.

4. The UE of claim 1 , the control circuitry further to determine whether the first or second data was successfully received on the sidelink interface; and

the transmit circuitry further to:

transmit a Hybrid Automatic Repeat Request Acknowledgement (HARQ ACK) on the sidelink interface to the Relay UE on determination that the first or second data was successfully received; and

transmit a Hybrid Automatic Repeat Request non-acknowledgement (HARQ NACK) on a sidelink interface to the Relay UE on determination that the first or second data was not successfully received.

5. The UE of claim 4 , the control circuitry further to multiplex HARQ ACKs and HARQ NACKs for multiple received subframes; and

the transmit circuitry further to transmit the multiplexed HARQ ACKs and HARQ NACK in a single uplink transmission.

6. The UE of claim 1 , the transmit circuitry further to transmit, on a first direct interface to the eNB, a Buffer Status Report (BSR), and a scheduling request to request third radio resources for uplink transmission.

7. The UE of claim 6 , the receive circuitry further to receive a third indication, via the downlink control channel, of the third radio resources on the sidelink interface to be used for transmitting third data; and

the transmit circuitry further to transmit the third data on the sidelink interface based on the third indication of third radio resources.

8. The UE of claim 1 the control circuitry further to:

determine a pathloss on the sidelink interface based on the received sidelink quality indicators; and

select a sidelink transmission power based on the determined pathloss.

9. One or more non-transitory, computer-readable media having instructions that, when executed on one or more processors, cause a device to:

receive a reference signal on a sidelink interface;

determine one or more sidelink quality indicators based on the received reference signal;

transmit the determined sidelink quality indicators to an Evolved Node B(eNB);

determine whether data was successfully received on the sidelink interface;

determine Hybrid Automatic Repeat Request (HARQ) information, including acknowledgements (ACKs) or negative-acknowledgements (NACKs) for multiple received subframes on the sidelink interface based on determination of whether the data was successfully received;

multiplex the HARQ information for the multiple received subframes; and

transmit the multiplexed HARQ information in a single uplink transmission.

10. An Evolved Node B (eNB) for controlling relay transmission via a sidelink interface in a wireless network, the eNB comprising:

receive circuitry to receive sidelink quality indicators associated with at least one sidelink channel between a remote UE and at least one Relay UE;

control circuitry to select one of a direct path and a relay path via a Relay UE based on the received sidelink quality indicators; and

transmit circuitry to:

transmit an indication of radio resources on the sidelink interface between the selected Relay UE and the Remote UE to be used for relay transmission between the eNB and the Remote UE in response to selection of a relay path; and

transmit a shared indication, via a downlink control channel, of first radio resources on the sidelink interface to be used by the selected Relay UE for transmitting data and used by the Remote UE for receiving data, wherein the indication of first radio resources is scrambled with a radio network temporary identifier (RNTI) common to the Remote UE and the selected Relay UE,

wherein the control circuitry is further to obtain a relay candidate set that includes the at least one Relay UE within communication range of the Remote UE, to obtain the relay candidate set, the control circuitry is to: determine Relay UEs within communication range of the Remote UE with the most desirable sidelink quality indicators; and select the Relay UEs with the most desirable sidelink quality indicators.

11. One or more non-transitory, computer-readable media having instructions that, when executed on one or more processors, cause a device to:

receive sidelink quality indicators associated with sidelink channels between a Remote user equipment (UE) and Relay UEs;

obtain a relay candidate set comprising at least one Relay UE within communication range of the Remote UE by determining the Relay UEs within communication range of the Remote UE with the most desirable sidelink quality indicators, and selecting the Relay UEs with the most desirable sidelink quality indicators;

selecting one of a direct path and a relay path via a Relay UE based on the received sidelink quality indicators;

transmit an indication of radio resources on a sidelink between a selected Relay UE and the Remote UE to be used for relay transmission between an Evolved Node B (eNB) and the Remote UE in response to selection of a relay path; and

transmit a shared indication, via a downlink control channel, of first radio resources on a sidelink interface to be used by the selected Relay UE for transmitting data and used by the Remote UE for receiving data, wherein the indication of first radio resources is scrambled with a RNTI common to the Remote UE and the selected Relay UE.