Method and apparatus for improving beam finding in a wireless communication system

Abstract

A method and apparatus for improving beam finding in a wireless communication system. In one embodiment, the method includes the base station detecting a first preamble transmission from a UE on a beam. The method also includes the base station examining extra transmissions to detect whether there are other beams which can be used to communicate with the UE. The method further includes the base station considering a beam set of the UE is complete if a rule is fulfilled, wherein the beam set of the UE includes beam(s) through which the UE could communicate with the base station.

1 . A method of a base station, comprising:
 the base station detects a first preamble transmission from a UE (User Equipment) on at least one beam;   the base station transmits a Random Access Response (RAR) to the UE in response to reception of the first preamble;   after transmitting the RAR, the base station continues to examine extra transmissions of reference signal from the UE to determine whether there are other beams which can be used to communicate with the UE; and   the base station considers a beam set of the UE is complete if a total number of extra transmissions from the UE reaches a pre-configured value, wherein the beam set of the UE includes beam(s) through which the UE could communicate with the base station.   
     
     
         2 . The method of  claim 1 , wherein the base station considers that the beam set of the UE is complete when all beams which can be used for communicating with the UE have been found. 
     
     
         3 . The method of  claim 1 , wherein a beam is included in the beam set of the UE if a signal strength received from the beam is greater than a threshold. 
     
     
         4 . A method of a UE (User Equipment), comprising:
 the UE transmits a preamble during a Random Access (RA) procedure for the base station to determine at least one beam for communicating with the UE;   the UE receives a Random Access Response (RAR) from a base station after transmission of the preamble; and   the UE performs several extra transmissions of reference signal to the base station after receiving the RAR from the base station so that the base station could examine the extra transmissions to detect whether there are other beams which can be used to communicate with the UE.   
     
     
         5 . The method of  claim 4 , wherein a total number of extra transmissions could be fixed or configurable. 
     
     
         6 . The method of  claim 4 , wherein the UE stops the extra transmissions when a specific signaling is received from the base station. 
     
     
         7 . The method of  claim 4 , wherein the UE receives the RAR from the base station after the base station detects the transmitted preamble on a beam. 
     
     
         8 . A User Equipment (UE), comprising:
 a control circuit;   a processor installed in the control circuit; and   a memory installed in the control circuit and operatively coupled to the processor;   wherein the processor is configured to execute a program code stored in the memory to:
 transmit a preamble during a Random Access (RA) procedure for the base station to determine at least one beam for communicating with the UE; 
 receive a Random Access Response (RAR) from a base station after transmission of the preamble; and 
 perform several extra transmissions of reference signal to the base station after receiving the RAR from the base station so that the base station could examine the extra transmissions to detect whether there are other beams which can be used to communicate with the UE. 
   
     
     
         9 . The UE of  claim 8 , wherein a total number of extra transmissions could be fixed or configurable. 
     
     
         10 . The UE of  claim 8 , wherein the processor is further configured to execute a program code stored in the memory to:
 stop the extra transmissions when a specific signaling is received from the base station.   
     
     
         11 . The UE of  claim 8 , wherein the processor is further configured to execute a program code stored in the memory to:
 receive the RAR from the base station after the base station detects the transmitted preamble on a beam.