An Improved Approach of Sending BSR and SR Based on MAC Layer in LTE System

The Buffer Status Report (BSR) and Scheduling Request (SR) are important procedures based on Medium Access Control (MAC) layer in Long Term Evolution (LTE) system. First, we study the BSR, SR and Semi-Persistent Scheduling (SPS) separately, then illustrate the priority of BSR and other data when sending MAC PDUs. The issue about the priority has been definitely defined by 3GPP, but it doesn't explain the reason, the article made a detailed analysis of it. The UE will send BSR and SR for gaining radio resources, the resources may be wasted if they exist at the same time. Finally we proposed a solution of deciding whether triggering BSR and SR in SPS and a solution of conflicts between padding BSR and other kinds of BSR.