Support For Beam Failure Recovery On Secondary Cell In Mobile Communications

Abstract

Techniques and examples of support for beam failure recovery on secondary cell in mobile communications are described. An apparatus (e.g., user equipment (UE)) detects a beam failure in wireless communication with a secondary cell (SCell) of a wireless network. The apparatus then signals on a network-configured resource an indication to inform the wireless network of the beam failure on the SCell. In response to the signaling, the apparatus receives a response from the wireless network.

What is claimed is: 
     
         1 . A method, comprising:
 detecting, by a processor of an apparatus, a beam failure in wireless communication with a secondary cell (SCell) of a wireless network;   signaling, by the processor, on a network-configured resource an indication to inform the wireless network of the beam failure on the SCell; and   receiving, by the processor, a response from the wireless network responsive to the signaling.   
     
     
         2 . The method of  claim 1 , wherein the network-configured resource comprises a contention-free physical random access channel (PRACH) resource on the SCell, and wherein the contention-free PRACH resource is dedicated for beam failure recovery for the SCell. 
     
     
         3 . The method of  claim 2 , wherein the receiving of the response comprises receiving the response from the SCell on which the beam failure is detected. 
     
     
         4 . The method of  claim 3 , wherein the signaling on the network-configured resource comprises transmitting a preamble using the contention-free PRACH resource on the SCell, and wherein the response comprises an uplink (UL) grant which includes an identity (ID) of the apparatus and optionally beam failure information. 
     
     
         5 . The method of  claim 2 , wherein the receiving of the response comprises receiving the response from a primary cell (PCell) of the wireless network. 
     
     
         6 . The method of  claim 5 , wherein the signaling on the network-configured resource comprises transmitting a preamble using the contention-free PRACH resource on the SCell, and wherein the response comprises an uplink (UL) grant which includes an identity (ID) of the apparatus and optionally beam failure information. 
     
     
         7 . The method of  claim 1 , wherein the network-configured resource comprises a contention-based physical random access channel (PRACH) resource on the SCell, and wherein the contention-based PRACH resource is dedicated for beam failure recovery for the SCell. 
     
     
         8 . The method of  claim 1 , wherein the network-configured resource comprises a contention-based physical random access channel (PRACH) resource on the SCell, and wherein the contention-based PRACH resource is not dedicated for beam failure recovery for the SCell. 
     
     
         9 . The method of  claim 1 , wherein the network-configured resource comprises a contention-free physical random access channel (PRACH) resource on a primary cell (PCell), and wherein the contention-free PRACH resource is dedicated for beam failure recovery for the SCell. 
     
     
         10 . The method of  claim 9 , wherein the contention-free PRACH resource is split to indicate to the network a serving cell on which the beam failure occurs. 
     
     
         11 . The method of  claim 9 , further comprising:
 in an event that serving cell information is indicated in the PRACH resource or a preamble signaled to the wireless network, performing a contention-free random access (CFRA) procedure responsive to receiving the response from the wireless network; or   in an event that the serving cell information is not indicated in the PRACH resource or any preamble signaled to the wireless network:
 performing a contention-based random access (CBRA) procedure; and 
 transmitting to the wireless network a message  3  (Msg 3 ) indicating the serving cell information with beam failure. 
   
     
     
         12 . The method of  claim 1 , wherein the network-configured resource comprises a contention-based physical random access channel (PRACH) resource on a primary cell (PCell), and wherein the contention-free PRACH resource is dedicated for beam failure recovery for the SCell. 
     
     
         13 . The method of  claim 12 , wherein the response comprises an uplink (UL) grant which includes an identity (ID) of the apparatus and information of a serving cell on which the beam failure occurs. 
     
     
         14 . The method of  claim 1 , wherein the network-configured resource comprises a contention-based physical random access channel (PRACH) resource on a primary cell (PCell), and wherein the contention-free PRACH resource is not dedicated for beam failure recovery for the SCell. 
     
     
         15 . The method of  claim 14 , wherein the response comprises an uplink (UL) grant which includes an identity (ID) of the apparatus and information of a serving cell on which the beam failure occurs. 
     
     
         16 . The method of  claim 1 , wherein the network-configured resource comprises a configured grant dedicated for beam failure report on a primary cell (PCell). 
     
     
         17 . The method of  claim 1 , wherein the network-configured resource is not dedicated for beam failure recovery, wherein the response comprises an uplink (UL) grant, further comprising:
 transmitting to the wireless network an indication in the UL grant that a random access channel (RACH) procedure is for the beam failure recovery.   
     
     
         18 . The method of  claim 1 , wherein the indication comprises a medium access control (MAC) control element (CE) with a separate logical channel identification (LCID). 
     
     
         19 . The method of  claim 18 , wherein the MAC CE comprises a bitmap that indicates an identity (ID) of the SCell on which the beam failure occurs. 
     
     
         20 . The method of  claim 18 , wherein the MAC CE comprises an identity (ID) of the SCell on which the beam failure occurs and an ID of a candidate beam with a relatively better reference signal received power (RSRP) on the SCell.