Hybrid random access and data transmission protocol for machine-to-machine communications in cellular networks

To address random access channel (RACH) congestion and high signaling overhead problems of machine-to-machine (M2M) communication in cellular networks, we propose a new design of a random access procedure that is exclusively engineered for the M2M communication. Our design has two prominent features. One is a fast signaling process that allows M2M user equipment to transmit data right after preamble transmission on a physical RACH to reduce the signaling overhead. The other is a self-optimization feature that allows the cellular system to produce optimal M2M throughput by adaptively changing resource block (RB) composition and an access barring parameter according to the amount of available RBs and the M2M traffic load. We derive a closed-form analytic formula for the M2M traffic throughput and propose a joint adaptive resource allocation and access barring scheme based on the analytic results. By simulation, we show that the proposed scheme exhibits a near-optimal performance in terms of the capacity.