Channel usage indication and synchronization for LTE operation in unlicensed bands

1. A method comprising:

receiving a downlink grant, the downlink grant comprising downlink control information (DCI) for a physical downlink shared channel (PDSCH) transmission, the DCI comprising an indication that indicates one or more resource elements to be rate matched around when receiving the PDSCH transmission;

determining, based on at least the indication comprised in the DCI, a total number of resource elements used for the PDSCH transmission;

determining a transport block size (TBS) for the PDSCH transmission based on the total number of resource elements used for the PDSCH transmission; and

receiving the PDSCH transmission comprising a transport block with the determined TBS, wherein receiving the PDSCH transmission comprises performing rate matching around the one or more resource elements that the indication in the DCI indicated to be rate matched around.

2. The method of claim 1 , wherein performing rate matching around the one or more resource elements comprises:

de-mapping symbols of the PDSCH transmission, wherein the one or more resource elements that the indication in the DCI indicated to be rate matched around are skipped during de-mapping.

3. The method of claim 1 , further comprising receiving a synchronization signal, wherein the synchronization signal comprises at least one of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), or a demodulation reference signal (DMRS).

4. The method of claim 1 , further comprising receiving a configuration from a first cell, wherein the configuration indicates which resource elements will be used by a second cell for transmission of a synchronization signal.

5. The method of claim 3 , further comprising performing frequency or timing estimation based on the synchronization signal transmission.

6. The method of claim 1 , further comprising:

determining a power offset between a synchronization signal transmission and one or more other downlink transmissions; and

determining a power level of the one or more other downlink transmissions based on the determined power offset.

7. The method of claim 6 , wherein the power offset is received in a radio resource control (RRC) message.

8. The method of claim 6 , wherein the one or more other downlink transmissions comprise a reference signal.

9. The method of claim 8 , wherein the reference signal comprises a channel state information reference signal (CSI-RS).

10. A wireless transmit/receive unit (WTRU) comprising:

a processor configured to:

receive a downlink grant, the downlink grant comprising downlink control information (DCI) for a physical downlink shared channel (PDSCH) transmission, the DCI comprising an indication that indicates one or more resource elements to be rate matched around when the PDSCH transmission is received;

determine, based on at least the indication comprised in the DCI, a total number of resource elements used for the PDSCH transmission;

determine a transport block size (TBS) for the PDSCH transmission based on the total number of resource elements used for the PDSCH transmission; and

receive the PDSCH transmission comprising a transport block with the determined TBS, wherein being configured to receive the PDSCH transmission comprises being configured to perform rate matching around the one or more resource elements that the indication in the DCI indicated to be rate matched around.

11. The WTRU of claim 10 , wherein the processor being configured to perform rate matching around the one or more resource elements comprises being further configured to de-map symbols of the PDSCH transmission, wherein the one or more resource elements that the indication in the DCI indicated to be rate matched around are skipped during de-mapping.

12. The WTRU of claim 10 , wherein the processor is further configured to receive a synchronization signal, and wherein the synchronization signal comprises at least one of a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH), a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS), or a demodulation reference signal (DMRS).

13. The WTRU of claim 10 , wherein the processor is further configured to receive a configuration from a first cell, wherein the configuration indicates which resource elements will be used by a second cell for transmission of a synchronization signal.

14. The WTRU of claim 12 , wherein the processor is further configured to perform frequency or timing estimation based on the synchronization signal transmission.

15. The WTRU of claim 10 , wherein the processor is further configured to:

determine a power offset between a synchronization signal transmission and one or more other downlink transmissions; and

determine a power level of the one or more other downlink transmissions based on the determined power offset.

16. The WTRU of claim 15 , wherein the power offset is received in a radio resource control (RRC) message.

17. The WTRU of claim 15 , wherein the one or more other downlink transmissions comprise a reference signal.

18. The WTRU of claim 17 , wherein the reference signal comprises a channel state information reference signal (CSI-RS).