LPWAN downlink using broadcast transmitters

Low Power Wide Area Networks (LPWANs) are a network type for connecting thousands of ultra-low power sensor-nodes to a base-station network, mainly using license-exempt frequency bands. Although the sensor-nodes use a transmit power of 10mW, such systems can reach a transmit distance of up to 40km by means of ultra-low payload bit-rates. However, in case of bi-directional communication the link budget between the uplink and downlink is high imbalanced, where the main problem is on the downlink. Common solutions such as increasing the transmit power on the downlink are not possible, as the maximum transmit power and duty cycle in the downlink are limited by regulations. The use of broadcast signals for the downlink, e.g. as part of DVB-T2 Future Extension Frames, may solve these problems. Therefore, a combination of LPWANs and broadcast systems seams very appealing from a technical point of view.