Delay and collision optimization for clustered machine type communications in random access procedures

In this paper, a clustered random access scheme based on packet aggregation method for machine type communication (MTC) is proposed, for which MTC devices are divided into clusters according to their locations. The neighboring devices are assigned to the same cluster. Devices within a group can communicate to each other by Device-to-Device (D2D) communication methods. The newly generated packets by MTC devices are transferred to the machine whose number of packets in the buffer is the closest to the given threshold in the group, which leads to shorter waiting time of packets in the buffer. Simulation results show that, the proposed scheme can significantly decrease collision probability and average delay of the random access procedure in machine type communications.