Direct and Indirect Access in Machine Type Communications: An Analytical Approach

Machine-to-machine (M2M) communications have emerged as a cost-effective, flexible and efficient solution of facilitating the pene- tration of independent ’things’ and machines in local networks and sys- tems. The latest releases of long-term evolution (LTE) such as LTE- Advanced (LTE-A) are being transformed to support the migration of M2M devices to end terminals. 3GPP supports the definition of techni- cal requirements and functional specifications that allows the adapting of existing technologies to support machine type communications (MTC) and the optimization of the design of advanced standards (e.g., LTE-A) for efficient data delivery. According to ETSI M2M architecture three types of MTC access methods are supported, the direct access, the gate- way access and the coordinator access. An MTC can access an evolved NodeB (eNB) with or without relay nodes. Hence coverage and connec- tivity issues appear on designing and deploying MTC architectures. This work is focused on studying and analyzing the probability of having at least k machine devices connected in modern cellular network, where the deployed M2M devices are directly or indirectly connected to the eNB node. The provided analytic framework is verified by simulation results that indicate suitable deployment conditions in specific MTC scenarios.