Method for downlink reception and user equipment using the same

1. A method for downlink reception used by a user equipment, the method comprising:

receiving an indication for indicating whether a channel correlated with a spatial domain reference signal is available; and

accessing the channel if the indication indicates the channel is available, comprising:

receiving a signal of the channel by using a spatial domain receive filter, wherein the spatial domain receive filter is determined according to the signal having the same quasi co-location assumption with the spatial domain reference signal by the user equipment.

2. The method of claim 1 , wherein the downlink reception is performed in an unlicensed band.

3. The method of claim 1 , further comprising:

receiving the indication by using the spatial domain receive filter corresponding to the spatial domain reference signal.

4. The method of claim 1 , wherein the downlink reception is performed by the user equipment on a bandwidth part of a serving cell.

5. The method of claim 1 , wherein the spatial domain reference signal is one of a synchronization signal block and a channel state information reference signal.

6. The method of claim 1 , wherein the step of receiving the indication for indicating whether the channel correlated with the spatial domain reference signal is available comprising:

obtaining the indication from at least one downlink reference signal.

7. The method of claim 6 , wherein the at least one downlink reference signal comprises a first downlink reference signal and a second downlink reference signal, wherein the first downlink reference signal and the second downlink reference signal are respectively allocated in at least one of different time-division multiplexed resources, different frequency-division multiplexed resources, different spatial-division multiplexed resources, or different code-division multiplexed resources.

8. The method of claim 6 , wherein the at least one downlink reference signal is configured within a bandwidth part pre-configured to the user equipment.

9. The method of claim 6 , wherein a bandwidth of the at least one downlink reference signal is above 80 percentage of 20 MHz.

10. The method of claim 6 , wherein the at least one downlink reference signal is transmitted by a single antenna port.

11. The method of claim 6 , wherein the at least one downlink reference signal is a channel state information reference signal.

12. The method of claim 1 , wherein the step of receiving the indication for indicating whether the channel correlated with the spatial domain reference signal is available comprising:

obtaining the indication from a downlink control information.

13. The method of claim 12 , wherein the downlink control information comprise at least one of the following: number of slots within the channel; number of time slots comprising an uplink resource within the channel; number of time slots comprising a downlink resource within the channel; number of uplink symbols in at least one time slot within the channel; or number of downlink symbols in at least one time slot within the channel.

14. The method of claim 12 , wherein the indication comprises a data bit, and the data bit indicates whether the channel corresponding to the spatial domain reference signal is available.

15. The method of claim 1 further comprising:

determining, according to the indication, priorities of a plurality of search spaces from small index to large index.

16. The method of claim 15 , wherein a first search space of the plurality of search spaces has higher priority than a second search space of the plurality of search spaces if the first search space is available and the second search space is not available.

17. The method of claim 1 , wherein a search space is available if the corresponding spatial domain reference signal is available.

18. The method of claim 1 further comprising:

determining, according to the indication, whether each of a plurality of search spaces is available.

19. The method of claim 1 further comprising:

obtaining a resource location of a physical downlink shared channel in a time slot from a downlink control information.

20. The method of claim 19 further comprising:

determining a quasi co-location assumption of the physical downlink shared channel according to at least one of the indication or an ID of a control resource set.

21. The method of claim 20 , wherein the control resource set has the lowest control resource set ID among a plurality of available control resource sets.

22. The method of claim 21 , wherein the plurality of available control resource sets are received in a previous time slot.

23. A user equipment comprising:

a transceiver; and

a processor connects to the transceiver and configured at least to:

receive, via the transceiver, an indication for indicating whether a channel correlated with a spatial domain reference signal is available; and

access, via the transceiver, the channel if the indication indicates the channel is available by:

receiving a signal of the channel by using a spatial domain receive filter, wherein the spatial domain receive filter is determined according to the signal having the same quasi co-location assumption with the spatial domain reference signal by the user equipment.

24. The method of claim 19 , wherein a timing offset between the downlink control information and the physical downlink shared channel is less than a time threshold.

25. The method of claim 19 , wherein a timing offset between the downlink control information and the physical downlink shared channel is larger than a time threshold.

26. The method of claim 19 , wherein the downlink control information and the physical downlink shared channel are transmitted in different data bursts.

27. The method of claim 1 further comprising:

determining, according to the indication, whether each of a plurality of control resource set is available.

28. The method of claim 21 , wherein the plurality of available control resource sets are received in the time slot.