Optimization of the predefined number of replications in a Ultra Narrow Band based IoT network

Ultra Narrow Band networks using Random-FTMA scheme are mainly characterized by the randomness both in time and frequency domain. The frequency randomness prevents from allocating orthogonal resources for transmission, and induces uncontrolled interference. By introducing diversity, replication mechanism is a promising candidate to enhance the reliability of such wireless network. Therefore, in this paper, by taking into account the randomness both in time and frequency domain, the replication mechanism has been considered. Considering the outage probability, we theoretically evaluate the system performance and show that there exists an optimal number of transmissions. Finally, we highlight that this number of repetitions can be easily optimized by considering a unique global parameter.