Wireless communication has come a long way from just cellular and Wi-Fi networks. With the expansion of modern devices, the need for loT (Internet of Things) capable networks has increased dramatically in just a short period of time. Despite this fast adoption, there is limited technical information on how Low Power Wide Area Networks (LPWAN) particularly Long Range Wide Area Network (LoRaWAN) works. The proprietary solution by Semtech requires understanding of the modulation scheme, channel access mechanism and constraints. This paper investigates the theoretical bounds of link and network capacity in LoRaWAn. We further provide an estimate on the number of devices allocated to a single gateway for a robust LPWAN based on LoRaWAN.