Resource Allocation Approaches for Two-Tiers Machine-to-Machine Communications in an Interference Limited Environment

One of the main challenges of supporting massive machine-type-communications (MTCs) by future mobile networks, is the radio access network (RAN) congestion. A viable solution is a hierarchical architecture where cluster-grouped machines are indirectly connected to the mobile network through a cluster gateway. This paper considers such an architecture and focuses on radio resource allocation to machine-clusters where resources can be spatially reused for concurrent transmissions. In particular, resources can be accessed simultaneously by machines of different clusters and by different communication phases, thus resulting in an interference-limited system. Three different resource partitioning schemes are proposed and evaluated, mainly differing on how interference is taken into account. The aim is to minimize the packet loss probability, and thus maximizing the spectral efficiency. Numerical results show the effectiveness of the proposed schemes in comparison to benchmark methods. In particular, by joining resource reuse and interference-mitigation, the efficiency improves significantly.