Inter-cell Interference Reduction Scheme for Uplink Transmission in NB-IoT Systems

In this paper, we propose an inter-cell interference (ICI) minimization scheme for uplink transmission in the narrowband internet of things (NB-IoT) systems. We first establish the theoretical ICI problem formulation and propose its corresponding solution for the orthogonal multiple access (OMA) NB-IoT system. Based on the theoretical formulation, we design a cooperative radio resource scheduler that reduces the impact of ICI and allocates transmit powers to reduce the energy consumption to the scheduled users in a multi-cell scenario. We compare the performance of the proposed scheme with that of some benchmark OMA schedulers. The results show that the proposed technique significantly reduces the impact of ICI and hence is more suitable for the massive connectivity of the NB-IoT system. For example, the users operating under the proposed approach experience up to 50% reduced energy consumption when compared to the best channel quality indicator (CQI) scheme. Furthermore, 30% and 35% improvements in terms of achieved user's data rates are obtained as compared to the MaxMin and round-robin schemes, respectively.