Method for determining valid subframe for non-licensed band in wireless communication system, and apparatus using the method
Provided are a method for determining a valid subframe for cell in a non-licensed band in a wireless communication system, and a wireless apparatus using the method. The method comprises: determining whether all orthogonal frequency division multiplexing (OFDM) symbols of the cell are usable; and when all of the OFDM symbols of the subframe are usable, determining whether the subframe is a valid subframe based on whether a channel state information-reference signal (CSI-RS) resource is present in the subframe.
1. A method for determining a valid subframe for a cell in an unlicensed band in a wireless communication system, the method comprising:
determining whether all of a plurality of orthogonal frequency division multiplexing (OFDM) symbols of a subframe in the cell are available; and
determining whether a channel state information-reference signal (CSI-RS) resource exists in the subframe,
wherein when all of the plurality of OFDM symbols of the subframe in the cell are available and when the CSI-RS resource exists in the subframe, the subframe is determined to be the valid subframe.
2. The method of claim 1 ,
wherein the cell in the unlicensed band is aggregated in carriers with a cell in a licensed band.
3. The method of claim 2 ,
wherein the cell in the licensed band is used as a primary cell, and the cell in the unlicensed band is used as a secondary cell.
4. The method of claim 1 , wherein the valid subframe is a valid downlink subframe or a valid special subframe.
5. The method of claim 1 , wherein a transmission power value or a clear channel assessment (CCA) threshold is informed to a terminal.
6. The method of claim 5 , wherein the CCA threshold is a value for determining whether the cell in the unlicensed band is accessible, and if the CCA threshold is higher than a threshold, an access probability is considered to be high, and if the CCA threshold is lower than the threshold, the access probability is considered to be low.
7. The method of claim 5 , wherein the transmission power value is in an inversely proportional relationship to the CCA threshold.
8. A wireless apparatus, comprising:
a radio frequency transceiver; and
a processor coupled to the RF transceiver,
wherein the processor is configured to:
determine whether all of a plurality of orthogonal frequency division multiplexing (OFDM) symbols of a subframe in a cell in an unlicensed band are available, and
determine whether a channel state information-reference signal (CSI-RS) resource exists in the subframe,
wherein when all of the plurality of OFDM symbols of the subframe in the cell are available and when the CSI-RS resource exists in the subframe, the subframe is determined to be the valid subframe.
9. The wireless apparatus of claim 8 ,
wherein the cell in the unlicensed band is aggregated in carriers with a cell in a licensed band.
10. The wireless apparatus of claim 9 ,
wherein the cell in the licensed band is used as a primary cell, and the cell in the unlicensed band is used as a secondary cell.
11. The wireless apparatus of claim 8 , wherein the valid subframe is a valid downlink subframe or a valid special subframe.
12. The wireless apparatus of claim 8 , wherein a transmission power value or a clear channel assessment (CCA) threshold is informed to a terminal.
13. The wireless apparatus of claim 12 , wherein the CCA threshold is a value for determining whether the cell in the unlicensed band is accessible, and if the CCA threshold is higher than a threshold, an access probability is considered to be high, and if the CCA threshold is lower than the threshold, the access probability is considered to be low.