Transceiving apparatus and spectrum access controlling method thereof

1. A spectrum access controlling method, adapted for a transceiving apparatus that uses an unlicensed spectrum and a licensed spectrum, the spectrum access controlling method comprising:

receiving, via the unlicensed spectrum or the licensed spectrum, feedback information related to accessing the unlicensed spectrum;

modifying an energy detection threshold for accessing the unlicensed spectrum according to the feedback information, comprising:

reducing the energy detection threshold if channel state information (CSI) of the unlicensed spectrum is inferior to a comparison threshold, wherein the feedback information comprises the CSI; and

increasing the energy detection threshold if the CSI is not inferior to the comparison threshold; and

determining whether to access the unlicensed spectrum according to the energy detection threshold,

wherein if a signal strength detected on the unlicensed spectrum is greater than the energy detection threshold, an access to the unlicensed spectrum is disabled; and

if the signal strength detected on the unlicensed spectrum is not greater than the energy detection threshold, the access to the unlicensed spectrum is performed.

2. The spectrum access controlling method according to claim 1 , wherein the feedback information is related to whether a transmission on the unlicensed spectrum is received correctly, and modifying the energy detection threshold according to the feedback information comprises:

reducing the energy detection threshold if the feedback information indicates the transmission on the unlicensed spectrum is not received correctly; and

increasing the energy detection threshold if the feedback information indicates the transmission on the unlicensed spectrum is received correctly.

3. The spectrum access controlling method according to claim 2 , wherein increasing the energy detection threshold comprises:

increasing the energy detection threshold if the number of times of consecutively receiving the feedback information indicating the transmission on the unlicensed spectrum is received correctly is greater than a number threshold; and

maintaining the energy detection threshold if the number of times of consecutively receiving the feedback information indicating the transmission on the unlicensed spectrum is received correctly is not greater than the number threshold.

4. The spectrum access controlling method according to claim 2 , wherein the feedback information comprises an acknowledgment (ACK) message or a non-acknowledgment (NACK) message.

5. The spectrum access controlling method according to claim 1 , wherein the feedback information is related to a channel condition.

6. The spectrum access controlling method according to claim 5 , wherein the CSI comprises a channel quality indicator (CQI), a precoding matrix indicator (PMI), and a rank indicator (RI).

7. The spectrum access controlling method according to claim 1 , wherein before receiving the feedback information related to the access to the unlicensed spectrum, the spectrum access controlling method further comprises:

setting the energy detection threshold of a schedule as a maximum, a minimum, or an average of a plurality of downlink data transmissions for the downlink data transmissions.

8. A transceiving apparatus, comprising:

a receiving circuit, receiving a signal through an unlicensed spectrum or a licensed spectrum;

a transmitting circuit, transmitting the signal through the unlicensed spectrum or the licensed spectrum; and

a processing circuit, coupled to the receiving circuit and the transmitting circuit and configured to:

receive, via the unlicensed spectrum or the licensed spectrum, feedback information related to accessing the unlicensed spectrum via the receiving circuit;

modify an energy detection threshold for accessing the unlicensed spectrum according to the feedback information, comprising:

reducing the energy detection threshold if channel state information (CSI) of the unlicensed spectrum is inferior to a comparison threshold, wherein the feedback information comprises the CSI; and

increasing the energy detection threshold if the CSI is not inferior to the comparison threshold; and

determine whether to access the unlicensed spectrum according to the energy detection threshold,

wherein if a signal strength detected on the unlicensed spectrum is greater than the energy detection threshold, an access to the unlicensed spectrum is disabled; and

if the signal strength detected on the unlicensed spectrum is not greater than the energy detection threshold, the access to the unlicensed spectrum is performed via the transmitting circuit.

9. The transceiving apparatus according to claim 8 , wherein the feedback information is related to whether a transmission using the unlicensed spectrum is received correctly, and the processing circuit is configured to:

reduce the energy detection threshold if the feedback information indicates the transmission on the unlicensed spectrum is not received correctly; and

increase the energy detection threshold if the feedback information indicates the transmission on the unlicensed spectrum is received correctly.

10. The transceiving apparatus according to claim 9 , wherein the processing circuit is configured to:

increase the energy detection threshold if the number of times of consecutively receiving the feedback information indicating the transmission on the unlicensed spectrum is received correctly is greater than a number threshold; and

maintain the energy detection threshold if the number of times of consecutively receiving the feedback information indicating the transmission on the unlicensed spectrum is received correctly is not greater than the number threshold.

11. The transceiving apparatus according to claim 9 , wherein the feedback information comprises an ACK message or a NACK message.

12. The transceiving apparatus according to claim 8 , wherein the feedback information is related to a channel condition.

13. The transceiving apparatus according to claim 12 , wherein the CSI comprises a CQI, a PMI, and a RI.

14. The transceiving apparatus according to claim 8 , wherein the processing circuit is configured to:

set the energy detection threshold of a schedule as a maximum, a minimum, or an average of a plurality of downlink data transmissions for the downlink data transmissions.

15. The transceiving apparatus according to claim 8 , wherein the transceiving apparatus is a base station or user equipment using a mobile network.