Scheduling M2M traffic over LTE uplink of a dense small cells network

We present an approach to schedule Long Term Evolution (LTE) uplink (UL) Machine to Machine (M2M) traffic in a densely deployed heterogeneous network, over the lamp posts of a big boulevard for smart city applications. The small cells operate with frequency reuse 1 and Inter-Cell Interference (ICI) is a critical issue to manage. We consider a Release 9 3rd Generation Partnership Project (3GPP) compliant scenario, where Single Carrier Frequency Division Multiple Access (SC-FDMA) is selected as the multiple access scheme, which requires that all Resource Block (RB)s allocated to a single user have to be contiguous in frequency within each time slot. This adjacency constraint limits the flexibility of the Frequency-Domain Packet Scheduling (FDPS) and Inter-Cell Interference Coordination (ICIC), when trying to maximize the scheduling objectives, and this is sufficient to make the problem NP-hard. We aim to solve an optimization problem, taking into account criteria such as the maximization of the overall throughput, the minimization of the radio resource usage, and the minimization of ICI. This can be modelled through a Mixed Integer Linear Programming (MILP) and solved through a heuristic implementable in the standards. We present simulation results in a 3GPP compliant network simulator, which support the effectivity of our algorithm, for different M2M applications, with respect to state of the art approaches.