## 3 Development of Thermal Condition Monitoring System
### Overview of WSNs and Communication Links Characteristics
#### 3.3.5 Gateway Application Layer Scheme  
In the industrial plants application, wireless sensor networks Gateway (GW) acts as the data sink for the sensor nodes and connect to the application platform through connections being it LAN (Ethernet), GSM, or others alike with acceptable Application Programming Interface (API). The significant element of any industrial WSNs configuration is to allow communication between the WSNs and API Gateway platform setup. The gateway can also be used to interface already existing wired sensor networks where required as inclusion. In multifaceted industrial application such as thermal condition monitoring, the gateway may use Ethernet and GSM interfaces with ZigBee to achieve the desired application concept. To enhance standardize the Gateway application interface, it then needs to be embedded with the API Gateway Abstraction Layer (GAL). The GAL allows interoperability of different WSNs with the application platform (Profibus-DP). GAL is compatible with ZigBee standard [56; 62; 77]. GAL can be directly incorporated as interface and its performance is in compliance with IEEE 802.15.4 [56]. The GAL functionality promotes the following features with appropriate data bus [54; 58; 62; 78]:  
* ZigBee WSNs to compose nodes, which runs specific tasks for a local and wide network application functions. * Low-layer interface to provide suitable network processor criteria usage to enhance the gateway to ZigBee platform. * Formation of GAL core to promote the gateway state machine application of the system. * Forwarding of the WSNs application functionalities for implementation by the GAL core. * Remote procedure call (RPC) layer to present the exposed system layer applications (local and remote) to operate in current implementation state. The RPC layer mechanism is used to make the process of executing code on a remote network or machine as simple and straightforward for local functions. Thus, enhance client call procedures as execution of returned functions. This makes the network server to simply define some routines that are to be assigned for export on ready. * The local applications of running the application and to assign the WSNs platform the convenience of managing convergence. The ZigBee gateway application layer proposes utility acceptable interface that is compatible with all processing signal connectivity of applications. To guarantee system signal real-time functioning, the gateway application layer embeds intelligence interrupt arbitration features, which neutralizes any delays the gateway interface might impact on the application signal on transmission. Thus, the working process of the application layer presents Profibus-DP as distributed peripheral to receive data from the ZigBee end nodes as slave and forwards command to the end field device for control actuation. This performs interface functioning of the ZigBee WSNs as coordinator. The Profibus-DP/ZigBee Gateway interlinks sensor nodes performance for control solutions from the GSM SMS alert notifications. The Profibus-DP is the first point of call to respond to the SMS alert notifications of the abnormal thermal condition through the gateway application layer [71; 72; 73; 74; 75; 79]. LoRa interface of nodes at the gateway layer does not associate with specific gateway bus like been shown in the ZigBee configuration. Instead, data transmitted by nodes are typically received by multiple gateways concurrently, which could end up being received by all the gateways. The processing techniques concept applies the adaptive data rate (ADR) for its algorithm estimation of the coding rate (CR) and spreading factor (SF) for parameters under specific channel condition. Consequently, each gateway sends the received packet from the end node to the cloud-based network server through standard IP connections [65; 66; 67; 68; 69; 70; 71; 72; 73]. This is a challenge for the nodes managing interface as critical network assets, where LoRa/LoRaWAN submitted data experiences critical events scenarios beyond real-time schedules.