Abstract
Due to the radio duty cycle restrictions in the sub- GHz unlicensed spectrum imposed in many regions, the downlink resources of the gateways in LoRaWAN are depleted fast even in the presence of moderate uplink traffic. To tackle the high demand for downlink traffic, additional gateways - from a pool of available positions - can be deployed. Not all gateways can initially be activated because of the extra operating costs that this action would cause. On the contrary, this paper studies the problem of dynamically activating the minimum estimated number of gateways in order to adapt the network to the traffic demands, and thus, improve the network reliability and energy consumption. The approach is based on theoretical foundations of downlink traffic as well as on empirical results and simple heuristics to select the gateway positions to be dynamically activated without taking into account the positions of the end-devices. Simulation results show that the proposed methodology in combination with the proposed heuristics exhibit a packet delivery ratio of over 90 % even with a single retransmission. The average energy consumption decreases considerably as well. Finally, the proposed approach presents similar results with an existing approach which, however, considers the positions of the end-devices as known.