**5. Research issues on WSN**

In this field, many research works have been done. And there is still emerging and trending domain for all researchers. Sub domains are also interested like WBAN, WPAN etc. as well as advance domains of this WSN is also interested and trending topic as IoT, IoE etc. In this fifth generation, IoT is everywhere. So, researchers can easily research on this topic and publish paper. Although advancement of this domain have been trending, but core WSN has many issues as disadvantages. Such as, it has seven layers. Each and every layer has many issues as challenges like simulator tools are very old configuration and simulator softwares are becoming obsolete. Hardware issues are there like devices should be supported with computer. Another important issues are sensor battery, energy consumption etc. Rather than those issues, most serious issue is security, because the lack of privacy constraints. Some main challenges are followed as:

