Conserving RACH Energy Usage with Flexible Preamble Allocation for IoT Coexisting with H2H Services

Random access channel (RACH) is the first step that needs to be conducted by any devices which require data transmission in modern cellular networks. Since LTE and beyond also often used to serve IoT application due to its wide coverage and availability, conserving energy is important. This paper presents a flexible preamble allocation scheme which is applied in RACH procedure and evaluates its energy consumption. The flexible preamble allocation enables base station to fine-tune its preamble allocation, which mainly used to prioritize H2H services over IoT ones. Such access prioritization translates in more efficient signaling transmissions during RACH procedure by reducing collision. The result demonstrates that the scheme can effectively reduce energy usage compared with the standard RACH procedure with shared preamble pool.