## 1 Introduction  
With the integration of agricultural and IT technology, accurate real-time monitoring and control systems for precision agriculture, like greenhouses, has been a desired requirement. Compared with traditional labor-intensive agriculture, reasonable environmental regulation, such as CO\({}_{2}\) concentrations in the greenhouse, can effectively increase crop yield [1; 2]. On the other hand, particularly in some developing countries, like China, with a relatively large demand in terms of grain storage and transport, the security of crops has become a significant issue. Therefore, a reasonable method to further reduce potential product losses caused by unpredictable harmful factors is of great importance in current agriculture. Therefore, vertical farming technology with accurate monitoring and control of agricultural factors has gradually attracted more attention in precise agriculture [3; 4; 5]. Besides the existing controllable environmental factors, including temperature and humidity, the potential effectiveness of CO\({}_{2}\) fertilization in the greenhouse requires accurate and reliable detection and a smart control on CO\({}_{2}\) concentration. Due to special application environmental conditions, the existing CO\({}_{2}\) sensing techniques, including semiconductor, electrochemical, and infrared absorption spectroscopy [6; 7], are greatly restricted and limited. For example, the mixed multi gas species in the greenhouse limit the feasibility of the semiconductor sensors. The commonly used electrochemical sensors, such as the commercially available MG811 from Winsen, have some inevitable shortcomings in sensing performances, including limited detection range, low accuracy, and high power consumption [7; 8]. Among the detailed sensing technologies, like direct absorption spectroscopy (DAS) [9; 10], photo-acoustic spectroscopy (PAS) [11], and tunable diode laser absorption spectroscopy (TDLAS) [12; 13; 14], because of its cost-effectiveness and feasibility in special applications in the environment of the greenhouse, the utilization of DAS sensing technology is reasonable and becoming increasingly popular. As a communication tool between the control platform and sensor nodes, wireless sensor networks (WSNs) have been deployed as a reasonable and low-cost communication technology which can avoid the costly installment of telecommunication infrastructures and wired communications [15]. Compared with Power Line Communication (PLC), the WSNs have advantages including fault-tolerant ability, multi-faceted detection based on high redundant deployments, and fixable installment ability in complex environments. Besides the application in prevention and early detection of forest fires [16], an application of real-time monitoring and smart fertilization control has been significantly developed in intelligent agriculture [17; 18], like smart compositing monitoring and control [19]. In addition, the relatively small size, implying a flexible integration with the sensor node, provides the possibility for managers to realize a unified management for an extensive planting area. In the application of wireless communication, some technologies, like Wi-Fi and Bluetooth, are mature and commonly used in the smart home [20]. However, due to the inherent data transmission rate characteristic which does not target the application for WSNs in the greenhouse, there is a relatively severe penalty in energy consumption. By contrast, wireless communication technologies at 443 MHz have a relatively strong penetration, indicating a long transmission distance for dealing with the inevitable plant shelter, which is a key advantage in its application in the greenhouse. Moreover, the integration between Global System for Mobile Communication (GSM) communication and WSN technology further enhances remote monitoring and control. In the current research, a Digital Enhanced Cordless Telecommunications (DECT) subnet is connected to a GSM coordinator [21].