## 7 Discussion and Future Perspectives  
By reviewing the different solar PV monitoring systems with regard to their application and advantages and disadvantages, it has been found in the context of data processing modules that BeagleBone is a powerful platform, but its usage is limited by a smaller number of external connections, and the fact that it is expensive and has a limited color resolution for HDMI. Arduino comes with user-friendly capabilities that are adaptable to several operating systems but it lacks a limited bit resolution and powerful module capabilities for processing complex data. Raspberry Pi is an effective module in the field of monitoring, but it lacks an RTC with a battery backup and BIOS. On the other hand, PLC has excellent outcomes in controlling data and can work for 5-10 years with a low cooling cost, yet it is incompatible with handling a large amount of data. Even though microcontrollers are reusable and energy-efficient, they have programming complexities that require a skilled person. Microprocessor-based prototypes are efficient and serve as a base in model development but are unsuited for new users as the programming languages, such as C/C++, require an expert programmer. In terms of transmission protocol modules, ZigBee has a low cost and a low power consumption. However, it suffers from signal interference and the loss of signals. Wi-Fi can transfer data at high speed, but it has an issue relating to low coverage area. Bluetooth exhibits easily upgradable characteristics and low power consumption. Nonetheless, it has a shortcoming in terms of authorization, authentication, and encryption. GSM comes with a low error rate with wide area coverage. Nevertheless, it experiences data interruption and data connection problems. LoRa is considered to be powerful module for long-rangedata transmission, but it is not suitable to send large payloads (limited to 100 bytes). Furthermore, the protocol does not allow for the continuous sending of data packets due to rules in relation to the frequency band it utilizes. The review provides some useful suggestions to design an efficient solar PV monitoring system for future research works which are highlighted below. Data transmission modules such as ZigBee and Wi-Fi have short-range transmissions. Nonetheless, the occurrence of signal interference is prevalent when the device is employed with other data transmission protocols. Thus, more exploration is required to eliminate the problems of signal interference for short-distance transmission. * Although data transmission modules are utilized to transmit data from sensor node to receiver node, the acquired data needs to be secured from external tampering. Therefore, careful attention is necessary to examine the security aspects of the data transmission modules in terms of theft of data, privatization, authentication of the third party, etc. Further, the implementation of NB-IoT technology could result in better scalability, quality of service, and security compared to unlicensed LPWA networks such as LoRa/Sigfox. * As the size of the solar PV systems is increasing, the complexity of handling several aspects such as data handling, security, efficiency, and transmission range needs to be studied. Hence the necessity for an efficient and reliable state-of-the-art wireless monitoring system to be developed. A new combination of sensor nodes with gateway devices could be designed. * The implementation of state-of-the-art technologies related to 5G and Bluetooth low energy can be utilized in solar PV monitoring systems due to several benefits such as low power consumption, greater transmission speed, greater capacity of remote execution with a greater number of attached devices and lower latency. * Several simulation platforms have been developed for the verification of the data received in solar PV monitoring systems. The accuracy of the validation of the data varies with different simulation platforms.