State-Based Uplink-Scheduling Scheme for Reducing Control Plane Latency of MCPTT Services

This paper addresses an uplink (UL) scheduling issue that arises in the midst of the recent trend in applying the commercial long term evolution (LTE) technology to public safety. Mission critical push-to-talk (MCPTT), which specifies a group communication service over LTE in public-safety scenarios, needs to satisfy the requirements of extremely short latency for its control procedures. We herein propose a practical UL-scheduling scheme, which can be feasible in the LTE system to shorten the time for the initial UL transmissions. Through the empirical assessment conducted on our LTE-based MCPTT testbed, the proposed scheme is validated to reduce the control plane latency with the little increment of implementation complexity.