# Efficient and Secured Mechanisms for Data Link in IoT WSNs: A Literature Review
## 4 Research Issues of WSN in IoT  
The first difficulty for all uses of the WSNs is security. Protecting one's private and confidential information has become a top priority for modern consumers. Data regarding \"personal health\" and corporate operations, for example, should not be made public. To preserve their privacy and security, they must be transmitted above WSNs. Authentication and encryption are critical stages in safeguarding WSNs, but they alone are not adequate. Data security must be maintained as new security issues arise with the development of technology, such as the interconnection of the IoT and WSNs. Despite recent developments in this sector, WSNs require substantial power from energy-restricted batteries to analyze and send data. Because of their limited size and computer capacity, wireless sensor nodes cannot perform to a great extent. WSNs have long been utilized in harsh, difficult-to-reach environments. Wireless sensor node resource limitations represent another issue for WSN-based systems. Apps' potential to interact with sensors, other users, and the cloud is called \"coverage and connectivity\". * Data aggregation methodologies;
* How to use sensors in a distributed environment;
* Clustering algorithms;
* Localization techniques;
* Rerouting protocols. The differences between IoT devices raise the question of interoperability. The WSN or IoT environment must be able to interface with the many heterogeneous devices that generate various types of data. With the increasing variety of IoT applications and linked devices, a continued effort is needed to achieve this. Facilitating communication among fast-moving objects, such as cars, and leveraging mobility to improve communication efficiency are difficult tasks in an age of constantly progressing Internet of things (IoT) systems. The mobility problem of WSNs and in the IoT sector has been addressed several times in the literature. Sensor nodes in the WSN scenario are only allowed to move inside the deployed zone of significance. As a result of the ubiquitous distribution of things in IoT scenarios, it is reasonable to expect that addressing the problem of things mobility would require the implementation of specific upgraded procedures. The reuse of IoT devices is necessary because of the rising need for essential information (such as heart rate, temperature, blood pressure, etc.) in different WSN or IoT applications. The ability to use gadgets in a variety of ways saves money. It is therefore always a goal to design a device for an application that can be reused in future applications. Things and sensor nodes already communicate regularly using current IoT and WSN systems. Battery life is quickly depleted by these exchanges, limiting non-stop operation to a few hours or days. As a result, improving processing and communication energy efficiency should be considered a significant open problem [24]. Many remedies have been presented in the literature to rectify this issue. To manage gathered data or events through different current solutions and services, the Internet of things (IoT) requires effective tactics. For IoT systems, the scalability criteria of WSNs cannot be met because of the higher number of IoT devices or other items linked to create an IoT system compared with conventional WSNs. Thus, the challenge of IoT scalability and flexibility must be addressed. An outstanding question rests in how flexible subscription and event monitoring systems may be provided while ensuring scalability for both objects and users. Various applications have experienced delays due to multiple devices connected to sensors that provide a wide variety of data. Delay-sensitive IoT gadgets have proven common in WSN networks. Sensor-based IoT network latency has been investigated. Due to various factors, such as topology, radio interference, and mobility, this problem may emerge as the number of IoT data sources grows; it is necessary to consider this direction. WSN security is confined to a region interested in classical WSNs and IoT systems.