B. **Topology issues**

1.**Geographic routing**: It is one of the most extensively used technique, however, the recent studies has shown that geographic routing can sometimes be useless in actual time deployments where location estimation system introduce regional errors;


## C. **Other issues are**:


## **1.5 Need of machine learning in WSN**

Machine learning [12] is a branch of Artificial Intelligence (AI). It is basically defined as the capability of a machine to mimic the behaviour of the human being that focuses on interpreting and analysing the patterns.

Meanwhile, its focus evolved and shifted more to the algorithms, which are more achievable and reliable. The machine learning techniques have been used extensively for variety of responsibilities which includes classification, regression, biometrics (such as speech recognition, eye detection, and fingerprint detection), fraud detection, etc. The sensor nodes in the WSNs might be heterogeneous, which are designed using numerous types of sensors according to the requirements of the network. The creators of network are more vulnerable to the issues regarding aggression or collection of statistics, reliability, clustering of nodes, safety and fraud detection [13]. Wireless sensor networks keep an eye on situations that are always changing. Either external factors or the system designers themselves started this dynamic behaviour. Sensor networks frequently use machine learning techniques to adapt to such circumstances in order to avoid needless redesign. A lot of doable solutions that maximise resource usage and increase network longevity are also inspired by machine learning. Lately, the use of machine learning algorithms has been experienced in WSNs. It enhances the performance of the network without the need for reprogramming. The algorithms also extract different levels of abstractions needed to perform variety of tasks with limited or no intervention. Some of the algorithms of ML deal with the design and functional issues of the network which were stated above.

The machine learning techniques [14] are used for the following reasons:

