Method and system for handling beam blockage in wireless communication system

1. A method for handling beam blockage in a wireless communication system, comprising:

detecting, by a user equipment (UE), a blockage of at least one beam;

determining, by the UE, a duration of the blockage of the at least one beam, wherein the duration of the blockage is determined at a time at which the blockage is present; and

indicating, by the UE, the blockage to perform a predetermined process that is selected based on the duration of the blockage, whether the UE is in a connected mode or an idle mode, and whether a beam failure instance counter reaches a beam failure instance maximum count,

wherein indicating, by the UE, the blockage comprises, in response to a beam failure instance counter not reaching the beam failure instance maximum count:

determining whether the duration of the blockage is less than a time of a beam failure recovery timer, and

holding a beam failure recovery procedure and performing a link switch by rerouting a packet to another link for the duration of the blockage when the duration of the blockage is less than the time of the beam failure recovery timer, or

triggering an early beam failure recovery procedure without waiting for expiry of the beam failure recovery timer and performing the beam switch or the link switch for the duration of the blockage when the duration of the blockage does not meet the time of the beam failure recovery timer.

2. The method of claim 1 , wherein indicating, by the UE, the blockage comprises:

determining whether the UE is in the connected mode or the idle mode;

when the UE is in the idle mode, indicating the blockage to at least one higher layer to hold a cell reselection and perform the cell reselection based on the duration of the blockage; and

when the UE is in the connected mode, indicating the blockage to the at least one higher layer to:

hold at least one ongoing procedure and resume the at least one ongoing procedure based on the duration of the blockage,

continue the at least one ongoing procedure without incrementing a counter associated with the at least one ongoing procedure during the duration of the blockage, or

apply a beam switch or a link switch for the duration of the blockage.

3. The method of claim 2 , wherein indicating the blockage to the at least one higher layer to hold the cell reselection and perform the cell reselection based on the duration of the blockage comprises:

determining that all of the at least one beam are blocked;

determining that the duration of the blockage meets a measurement evaluation criteria of a serving cell;

determining that the duration of the blockage meets a measurement evaluation criteria for a cell reselection; and

holding the cell resection and then performing the cell reselection.

4. The method of claim 2 , wherein holding the at least one ongoing procedure and then resuming the at least one ongoing procedure based on the duration of the blockage comprises one of:

holding by stopping an ongoing random access channel (RACH) procedure for the duration of the blockage and resuming the RACH procedure after an offset which is obtained based on the duration of the blockage,

holding by stopping an ongoing scheduling request (SR) procedure for the duration of the blockage and resuming the SR procedure after an offset obtained based on the duration of the blockage, and

holding by stopping an ongoing transmission or retransmission procedure for the duration of the blockage and resuming the transmission or retransmission procedure after the duration of the blockage.

5. The method of claim 1 , wherein indicating, by the UE, the blockage further comprises:

in response to the beam failure instance counter reaching the beam failure instance maximum count, indicating the blockage to the at least one higher layer and instructing the at least one higher layer to:

hold the at least one ongoing procedure and then resume the at least one ongoing procedure based on the duration of the blockage, or

continue the at least one ongoing procedure without incrementing the counter associated with the at least one ongoing procedure during the duration of the blockage,

wherein the beam failure instance counter is determined based on the duration of the blockage and a measurement periodicity indicated by a physical layer.

6. The method of claim 5 , wherein rerouting the packet to the another link for the duration of the blockage comprises:

indicating a packet data convergence protocol (PDCP) layer on the duration of the blockage based on a higher layer retransmission timer, and selecting the another link for re-routing the packet based on the duration of the blockage and the higher layer retransmission timer; or

indicating the PDCP layer on the duration of the blockage based on a PDCP reordering timer, and selecting the another link for re-routing the packet based on the duration of the blockage and the PDCP reordering timer.

7. The method of claim 1 , wherein performing the beam switch or the link switch for the duration of the blockage when the duration of the blockage does not meet the time of the beam failure recovery timer comprises:

performing a beam selection procedure to select at least one candidate beam from a plurality of candidate beams for the early beam failure recovery procedure;

determining whether all of the plurality of candidate beams are blocked;

performing the link switch by rerouting the packet to another link for the duration of the blockage when all of the plurality of candidate beams are blocked; and

performing the beam switch by triggering a random access channel (RACH) procedure on the at least one selected candidate beam when at least one of the plurality of candidate beams is not blocked.

8. The method of claim 1 , wherein detecting, by the UE, the blockage of the at least one beam comprises:

determining a first reference signal received power (RSRP) of the at least one beam or a first signal-to-interference-plus-noise ratio (SINR) of the at least one beam at a first time period;

determining a second RSRP of the at least one beam or a second SINR of the at least one beam at a second time period;

determining a difference between the first RSRP and the second RSRP or the first SINR and the second SINR;

determining whether the difference meets a blockage criteria, wherein the blockage criteria is dynamically measured and configured by the UE; and

detecting the blockage at the second time period due to the second RSRP or the second SINR of the at least one beam when the difference meets the blockage criteria.

9. The method of claim 1 , further comprising:

indicating, by the UE, a link indication to inform a base station in the wireless communication system to not use the at least one beam for the duration of the blockage,

wherein the duration of the blockage is determined at the time period based on a median of historic blockage durations of the time period, and

wherein the link indication is one of a medium access control (MAC) control element (MAC-CE) based indication, a physical uplink control channel (PUCCH) based indication and a physical uplink shared channel (PUSCH) based indication.

10. A user equipment (UE) for handling beam blockage in a wireless communication system, comprising:

a memory;

at least one processor; and

a beam blockage controller, operably coupled to the memory and the at least one processor, configured to:

detect a blockage of at least one beam;

determine a duration of the blockage of the at least one beam, wherein the duration of the blockage is determined at a time at which the blockage is present; and

indicate the blockage to perform a predetermined process that is selected based on the duration of the blockage, whether the UE is in a connected mode or an idle mode, and whether a beam failure instance counter reaches a beam failure instance maximum count,

wherein the beam blockage controller is further configured to indicate the blockage to the at least one higher layer to apply the beam switch or the link switch for the duration of the blockage by:

determining that the beam failure instance counter does not reach the beam failure instance maximum count,

determining whether the duration of the blockage is less than a beam failure recovery timer, and

holding a beam failure recovery procedure and performing a link switch by rerouting a packet to another link for the duration of the blockage when the duration of the blockage is less than the beam failure recovery timer, or

triggering an early beam failure recovery procedure without waiting for expiry of the beam failure recovery timer and performing the beam switch or the link switch for the duration of the blockage when the duration of the blockage exceeds a time of the beam failure recovery timer.

11. The UE of claim 10 , wherein the beam blockage controller is further configured to indicate the blockage by:

determining whether the UE is in the connected mode or the idle mode;

when the UE is in the idle mode, indicating the blockage to at least one higher layer to hold a cell reselection and then perform the cell reselection based on the duration of the blockage; and

when the UE is in the connected mode, indicating the blockage to the at least one higher layer to:

hold at least one ongoing procedure and then resume the at least one ongoing procedure based on the duration of the blockage,

continue the at least one ongoing procedure without incrementing a counter associated with the at least one ongoing procedure during the duration of the blockage, or

apply a beam switch or a link switch for the duration of the blockage.

12. The UE of claim 11 , wherein the beam blockage controller is further configured to indicate the blockage to the at least one higher layer to hold the cell reselection and perform the cell reselection based on the duration of the blockage by:

determining that all of the at least one beam are blocked;

determining that the duration of the blockage meets a measurement evaluation criteria of a serving cell;

determining that the duration of the blockage meets a measurement evaluation criteria for a cell reselection; and

holding the cell resection and then performing the cell reselection,

wherein the beam blockage controller is further configured to indicate the blockage to the at least one higher layer to hold the at least one ongoing procedure and then resume the at least one ongoing procedure based on the duration of the blockage or continue the at least one ongoing procedure without incrementing a counter associated with the at least one procedure during the duration of the blockage by:

determining that the beam failure instance counter is less than the beam failure instance maximum count; and

indicating the blockage to the at least one higher layer to:

hold the at least one ongoing procedure and then resume the at least one ongoing procedure based on the duration of the blockage, or

continue the at least one ongoing procedure without incrementing the counter associated with the at least one procedure during the duration of the blockage.

13. The UE of claim 12 , wherein the beam blockage controller is further configured to hold and resume the at least one procedure based on the duration of the blockage by one of:

holding by stopping an ongoing random access channel (RACH) procedure for the duration of the blockage and resuming the RACH procedure after an offset which is obtained based on the duration of the blockage,

holding by stopping an ongoing scheduling request (SR) procedure for the duration of the blockage and resuming the SR procedure after an offset obtained based on the duration of the blockage, and

holding by stopping an ongoing transmission or retransmission procedure for the duration of the blockage and resuming the transmission or retransmission procedure after the duration of the blockage.

14. The UE of claim 12 , wherein the beam blockage controller is further configured to rerouting the packet to the another link for the duration of the blockage by:

indicating a packet data convergence protocol (PDCP) layer on the duration of the blockage based on the higher layer retransmission timer, and selecting the another link for re-routing the packet based on the duration of the blockage and the higher layer retransmission timer; or

indicating the PDCP layer on the duration of the blockage based on a PDCP reordering timer, and selecting the another link for re-routing the packet based on the duration of the blockage and the PDCP reordering timer,

wherein the beam blockage controller is further configured to detect the blockage of the at least one beam by:

determining a first reference signal received power (RSRP) of the at least one beam or a first signal-to-interference-plus-noise ratio (SINR) of the at least one beam at a first time period;

determining a second RSRP of the at least one beam or a second SINR of the at least one beam at a second time period;

determining a difference between the first RSRP and the second RSRP or the first SINR and the second SINR;

determining whether the difference meets a blockage criteria, wherein the blockage criteria is dynamically measured and configured by the UE; and

detecting the blockage at the second time period due to the second RSRP or the second SINR of the at least one beam when the difference meets the blockage criteria.

15. The UE of claim 10 , wherein the beam blockage controller is further configured to perform the beam switch or the link switch for the duration of the blockage when the duration of the blockage does not meets the beam failure recovery timer by:

performing a beam selection procedure to select at least one candidate beam from a plurality of candidate beams for the early beam failure recovery procedure;

determining whether all of the plurality of candidate beams are blocked;

performing the link switch by rerouting a packet to another link for the duration of the blockage when all of the plurality of candidate beams are blocked; and

performing the beam switch by triggering a random access channel (RACH) procedure on the at least one selected candidate beam when at least one of the plurality of candidate beams is not blocked.

16. The UE of claim 15 , wherein the beam blockage controller is further configured to select one of the plurality of candidate beams based on a prioritization, wherein the prioritization is based on previous measurement statistics on the plurality of candidate beams,

wherein the beam failure instance counter is determined based on the duration of the blockage and a measurement periodicity indicated by a physical layer, and

wherein the duration of the blockage is determined at the time period based on a median of historic blockage durations of the time period.