###### Abstract  
To reach the goal of sustainable agriculture, smart farming is taking advantage of the Unmanned Aerial Vehicles (UAVs) and Internet of Things (IoT) paradigm. These smart farms are designed to be run by interconnected devices and vehicles. Some enormous potentials can be achieved by the integration of different IoT technologies to achieve automated operations with minimum supervision. This paper outlines some major applications of IoT and UAV in smart farming, explores the communication technologies, network functionalities and connectivity requirements for Smart farming. The connectivity limitations of smart agriculture and it's solutions are analysed with two case studies. In case study-1, we propose and evaluate meshed Long Range Wide Area Network (LoRaWAN) gateways to address connectivity limitations of Smart Farming. While in case study-2, we explore satellite communication systems to provide connectivity to smart farms in remote areas of Australia. Finally, we conclude the paper by identifying future research challenges on this topic and outlining directions to address those challenges. agriculture; Internet of Things (IoT); smart farming; sustainable future; sustainable smart farming; Unmanned Aerial Vehicles (UAVs) 2021 13 1821 or disease detection, monitoring and predicting weather conditions, soil conditions, etc. As a consequence, UAV and IoT based technologies facilitate adequate use of resources such as water, pesticides or agro-chemicals. Additionally, these smart technologies have proven to increase the quality of crop yield [4] and reduce environmental footprint from agricultural sector [2]. Some major features of IoT and UAV based smart farming includes, but are not limited to, the following [5]:  
* Field Monitoring: Smart farming helps in reducing crop waste by adapting better monitoring, accurate data obtaining and data processing. * Livestock Monitoring and Tracking: Smart farming helps to identify the location of animals grazing in open area within big stables. Technology also helps to measure the status of ventilation and air quality in farms and detect harmful gases from excrement. * Application in Green Houses: Smart farming controls micro-climate conditions towards the aim of maximizing the production and quality of fruits and vegetables within green houses. * Compost Management: As a measure of preventing fungus and other microbial contaminants, smart farming helps to control the level of humidity and temperature in crops such as straw, hay, etc. * Offspring Care: Smart farming controls the growing conditions of the offspring in animal farms, hence ensuring their survival and health. On the other hand, UAVs have been incorporated into smart farming towards the aim of providing additional perspectives, such as, imagery analysis and agricultural surveillance [6]. UAVs not only facilitate image analysis and processing of the agricultural area, but also, offer in-depth situation awareness by patrolling over an area of interest [7]. Moreover, UAVs can also be used to provide important information to grounded monitoring stations by traversing data towards them. The applications UAVs are expanded to many areas of agriculture, including insecticide and fertilizer prospecting and spraying, seed planting, weed recognition, fertility assessment, mapping, and crop forecasting. These recent advancements of IoT and UAV based smart farming are helping the world to reach the goals of \"The 2030 Agenda for Sustainable Development\", where the United Nation (UN) and international community set a target to eliminate Hunger by 2030 [8]. However, there are many factors that limit the advantage of smart farming, where connectivity is one of the most crucial factors that may affect the benefits of IoT and UAVs in smart agriculture [1; 9]. In order to achieve a seamless operation of the IoT and UAV-based smart farming, it is very important to ensure seamless connectivity and high level of communication efficiency among sensors-equipped devices.