Method and apparatus for requesting resource for control element transmission in a wireless communication system

Abstract

A method and apparatus are disclosed from the perspective of a UE, wherein the UE is allocated with multiple SR configurations by a network node. In one embodiment, the method includes the UE triggering a MAC control element if a timer expires. The method also includes the UE triggering a SR for the MAC control element. The method also includes the UE transmitting the SR based on a first SR configuration of the multiple SR configurations, wherein the first SR configuration is associated with a highest priority logical channel having data available for transmission when the MAC control element is triggered.

What is claimed is: 
     
         1 . A method of a User Equipment (UE), wherein the UE is allocated with multiple Scheduling Request (SR) configurations, comprising:
 starting a timer upon sending a first Medium Access Control (MAC) control element, wherein the first MAC control element is triggered due to data available for transmission;   triggering a second MAC control element in response to the timer expiry;   selecting a first SR configuration among the multiple SR configurations; and   transmitting a SR based on the first SR configuration of the multiple SR configurations.   
     
     
         2 . The method of  claim 1 , wherein the SR is triggered for the second MAC control element. 
     
     
         3 . The method of  claim 1 , wherein the timer is a retxBSR-Timer, and wherein there are multiple logical channels still having data available for transmission when the timer expires. 
     
     
         4 . The method of  claim 1 , wherein the first and second MAC control elements are BSR (Buffer Status Report). 
     
     
         5 . The method of  claim 1 , wherein the first SR configuration is associated with a highest priority logical channel determined by comparing priorities of each of the multiple logical channels. 
     
     
         6 . The method of  claim 1 , wherein the first SR configuration is associated with the highest priority logical channel based on an identity of the highest priority logical channel. 
     
     
         7 . The method of  claim 1 , further comprising triggering the first MAC control element if the UE has data for any logical channels that belong to a Logical Channel Group. 
     
     
         8 . A User Equipment (UE), comprising:
 a memory; and   a processor operatively coupled to the memory, wherein the processor is configured to execute a program code to:
 start a timer upon sending a first Medium Access Control (MAC) control element, wherein the first MAC control element is triggered due to data available for transmission; 
 trigger a second MAC control element in response to the timer expiry; 
 select a first Scheduling Request (SR) configuration among multiple SR configurations; and 
 transmit a SR based on the first SR configuration of the multiple SR configurations. 
   
     
     
         9 . The UE of  claim 8 , wherein the SR is triggered for the second MAC control element. 
     
     
         10 . The UE of  claim 8 , wherein the timer is a retxBSR-Timer, and wherein there are multiple logical channels still having data available for transmission when the timer expires. 
     
     
         11 . The UE of  claim 8 , wherein the first and second MAC control elements are BSR (Buffer Status Report). 
     
     
         12 . The UE of  claim 8 , wherein the first SR configuration is associated with a highest priority logical channel determined by comparing priorities of each of the multiple logical channels. 
     
     
         13 . The UE of  claim 8 , wherein the first SR configuration is associated with the highest priority logical channel based on an identity of the highest priority logical channel. 
     
     
         14 . The UE of  claim 8 , wherein the processor is further configured to execute a program code to trigger the first MAC control element if the UE has data for any logical channels that belong to a Logical Channel Group. 
     
     
         15 . A method of a User Equipment (UE), wherein the UE is allocated with a plurality of Scheduling Request (SR) configurations, comprising:
 starting a timer upon sending a first Medium Access Control (MAC) control element, wherein the first MAC control element is triggered due to data available for transmission;   triggering a second MAC control element in response to the timer expiry;   selecting a first SR configuration among the plurality of SR configurations; and   transmitting a SR based on the first SR configuration of the plurality of SR configurations.   
     
     
         16 . The method of  claim 15 , wherein the SR is triggered for the second MAC control element. 
     
     
         17 . The method of  claim 15 , wherein the timer is a retxBSR-Timer. 
     
     
         18 . The method of  claim 15 , wherein the first and second MAC control elements are BSR (Buffer Status Report). 
     
     
         19 . The method of  claim 15 , wherein the first SR configuration is associated with a highest priority logical channel determined by an identity. 
     
     
         20 . The method of  claim 15 , further comprising triggering the first MAC control element if the UE has data for any logical channels that belong to a Logical Channel Group.