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Although there are numerous problems linked with the sensor networks, the energy-hole problem is one of the serious issues connected to WSN. To overcome this issue, a mobile sink is periodically traversed to fetch data from the sensor nodes deployed in the field by keeping all other nodes in the network as static. Rather than visiting all the nodes, which may result in delay, a mobile sink is permitted to visit only the rendezvous points i.e.; the head node and the rest of the nodes sends data to the nearest head node. The two important challenges in this approach are: finding the exact rendezvous nodes at different locations in the network and also finding the path in which the mobile node needs to be traversed. Optimum rendezvous points not only improve the data aggregation but also maximize the lifetime of the network. This paper suggests a new-fangled optimization approach called the P-AACO, Power-Aware Scheduling and clustering algorithm based on AACO, where an advanced ant colony optimization to determine the optimal mobile sink path for wireless sensor networks. To achieve the desired goals of optimizing network lifetime and minimizing latency, this strategy incorporates an effective mechanism to find the optimal collection of rendezvous points. Reselection of RP is carried out after every stage of transmission to ensure energy utilization and balance the network load. The proposed protocol is compared with LEACH and WRP by taking the performance metrics such as delay, throughput, and energy into consideration. The simulation was carried out using the ns2 simulator and the from the results obtained, it is evident that the merits of P-AACO are manifold and it outperforms the traditional protocols.

Safety is one of the main aspects of the industry, specifically core industry. To minimize material loss and human health damage, a protection system along with a rapid communication system is necessary inside the industry. The primary objective of this work is to design a green environment monitoring system for industries using Li-Fi technology to provide secure communication, high data rate transfer, and a pollution-free environment. The traditional system of wired communication along with the Fixed Base station has not been so effective. In this proposed protocol, as a source for data transmission, light-emitting diodes are used and are favored as they have a longer life-time. Different sensors are used to track different parameters in an industrial setting and these sensors relay sensed information in terms of LED flickering using Li-Fi technology. In this work, the main aim is to focus on the detection of abnormal gases, fire, and unusual vibrations in the industries and transmitting this information to the workers using the Li-Fi transceiver. Various adversities hindering the workers and emergency information can be efficiently communicated using this technology. If the sensor senses a value beyond the predefined threshold value, information is sent through text and alarm to the workers. The developed system surpasses most current systems as it provides communication at a rate of 1.5 Mbps with a range of 10 meters and, more importantly, is free of electromagnetic interference. Henceforth, the visible light communication (VLC) technique is exploited for industrial applications.

Information dissemination using digital notice board plays an imperative role in this digital world. This work is primarily aimed at developing a wireless information board for displaying and broadcasting the announcements and notices that the user sends from the Internet using the IOT technology. By providing a sufficient power supply, the Raspberry Pi, node MCU and LED display work properly and the display is controlled by the android application. The application can be used by connecting it to the internet and this enables the admin to send the information from wherever in the planet and could be visualized in a matter of seconds. The admin uses the app by setting the correct username and password for WIFI. For sending information, PC or mobile phone are utilised and at recipient end, raspberry Pi is connected to the Web. The admin can send the data in the form of text or voice, which in turn would be displayed on the distant noticeboard. The LED display is to display the text/voice that the user has sent and the speaker is to announce the received text message. The displaying text would be scrolling in the display. By using the text to speech software, announcement the text that is scrolling on the LED screen become possible. Earlier the Wi-Fi notification board had been used and thereby experiencing a limit on coverage. In this proposed method, the Internet is used as a means of communication and no coverage problem exists.

The objective of EMBHMAC is to reduce the energy consumption and delay in wireless sensor networks. The working of proposed protocol is based on sender's guidance, overhearing, hybrid TDMA/FDMA concept and controlled power mechanism. The sender's guidance reduces the redundant transmission and collision by giving guidance of how to forward the packets. Overhearing reduces the active time of nodes. Asynchronous duty-cycling can reduce the energy consumption by carrying out alternation between sleep mode and active mode. Delay in MAC layer is increased as a result of this. The proposed protocol can overcome this problem by using the hybrid TDMA/FDMA concept where within the same network we can use different frequencies and multiple transmissions can be carried out at same time slot and hence reduces delay. Controlled power mechanism controls the power desired for transmission of data by varying the transmission power and this increases energy efficiency. The proposed protocol is compared with ADB and EMBA. The performance of proposed protocol is carried out in the absence and presence of an obstacle also.

In this paper, we propose an energy efficient hybrid MAC multihop broadcast protocol for asynchronous duty-cycled wireless sensor networks called EHMBA, where each node independently wakes up according to their own schedule and incorporated the concept of hybrid MAC and power transmission adjustment to reduce the delay and to increase the energy efficiency in the network. The working of EHMBA is based on two different techniques: one is forwarder's guidance and overhearing of broadcast messages and ACKs and the other is with the incorporation of hybrid MAC and power transmission adjustment mechanism. The forwarder's guidance presents how to forward the broadcast message and significantly reduces redundant transmission and collision. Overhearing reduces the number of transmissions and minimizes the number of active nodes. The broadcast message has to wait till the node wakes up as each node has its own time slot in asynchronous duty-cycled protocols. The proposed protocol can overcome this problem, where within the same network, we can have different frequencies and multiple transmissions can be carried out at the same time slot and hence reduces delay. The transmission power adjustment mechanism helps to suitably vary the transmission power in order to reduce energy consumption.