Wireless-Sensor-Networks in advance wireless mobile network
- 2. Introduction to Wireless Sensor Networks A Wireless sensor network(WSN) can be defined as a network of devices that can transfer the information gathered from a monitored field through wireless links. The data is forwarded through multiple nodes, and with a gateway, the data is connected to other networks like wireless Ethernet. WSN is one kind of wireless network which includes a large number of circulating, self- directed, minute, low powered devices named sensor nodes called motes. These networks certainly cover a huge number of spatially distributed, little, battery-operated, embedded devices that are networked to caringly collect, process, and transfer data to the operators, and it has the capabilities of computing & processing. These networks are used to monitor physical or environmental conditions like sound, pressure, temperature and co-operatively pass data through the network to a main location.
- 3. How Wireless Sensors Work Sensing 1. The sensor detects physical phenomena like temperature, humidity, motion, or light. Processing 1. The sensor processes the data it collects, often converting it into a digital signal. Communication The sensor uses wireless communication technologies like Wi-Fi, Bluetooth, Zigbee etc to transmit the data to a receiver or central system. Data Analysis The received data can be analyzed in real-time or stored for later use.
- 4. WSN NETWORK TOPOLOGIES • Star topology • Tree Topology • Mesh Topology
- 5. ARCHITECTURE OF WIRELESS SENSOR NETWORK • WSN architecture follows the OSI architecture Model. • It includes five layers and three cross layers. • Five layers - application, transport, n/w, data link & physical layer. • The three cross planes - power management, mobility management, and taskmanagement. • The layers of the WSN are used to accomplish the n/w and make the sensors worktogether in order to raise the complete efficiency of the network. The three cross layers include the following: • Power Management Plane • Mobility Management Plane • Task Management Plane These three cross layers are mainly used for controlling the network as well as to make the sensors function as one in order to enhance the overall network efficiency. The above mentioned five layers of WSN are discussed below. 1. Physical Layer The physical layer provides an edge for transferring a stream of bits above physical medium. This layer is responsible for :- • selection of frequency • generation of a carrier frequency • signal detection, • Modulation & Demodulation • Data encryption/decryption The most important parameters which are to be considered while designing Physical layer in wireless sensor networks are:- 1. Low Power Consumption. 2. Low Transmission and Reception range. 3. Interference from other systems, working in the same band. 4. Low complexity. 5. Low duty cycle, i.e. most of the time sensor nodes are switched off. 6. Low data rates most of the time and high data rate only for a short period of time. The most challenging aspect in physical layer design for sensor networks is to find, low cost transceivers which consume less power, simple modulation schemes which are robust enough to provide required service.
- 6. 2. Data Link Layer The data link layer is liable for multiplexing data frame detection, data streams, MAC & error control. Generally, the errors or unreliability comes from 1. Co- channel interference at the MAC layer and this problem is solved by MAC protocols. 2. Multipath fading and shadowing at the physical layer and this problem is solved by forward error correction (FEC) and automatic repeat request (ARQ). ARQ: not popular in WSN because of additional re-transmission cost and overhead. ARQ is not efficient to frame error detection so all the frame has to retransmitted if there is a single bit error. FEC: decreases the number of retransmission by adding redundant data on each message so the receiver can detect and correct errors. By that we can avoid re-transmission and wait for ACK . 3. Network Layer The main function of the network layer is routing. The major tasks are in the power conserving, partial memory, buffers, and sensor don’t have a universal ID and have to be self-organized. The basic idea of the routing protocol is to define a reliable path and redundant paths according to a certain scale called metric, which differs from protocol to protocol. There is a lot of routing protocols available for this layer. • Flat routing (for example, direct diffusion) • hierarchal routing (for example, LEACH)Power management techniques existing at the network layer are concerned with performing power efficient routing through a multi-hop network. Methods Used: 1. Backbone-Based Routing (Charge-Based Clustering): • Some nodes stay always active (called backbone nodes). • Other nodes can sleep to save energy. • Backbone nodes help create paths for data. • Every node must be within one hop of a backbone node. • Backbone nodes are rotated over time to balance energy use. 2. Topology Control-Based Routing: • Controls which nodes are connected to save power. 3. Hybrid Approaches: • Combine backbone and topology control methods.
- 7. 4. TRANSPORT LAYER 1. The function of the transport layer is to deliver congestion avoidance and reliability where a lot of protocols intended to offer this function are either practical on the upstream. 2. These protocols use dissimilar mechanisms for loss recognition and loss recovery. The transport layer is exactly needed when a system is planned to contact other networks. 3. Providing a reliable loss recovery is more energy-efficient and that is one of the main reasons why TCP is not fit for WSN. In general, Transport layers can be separated into Packet driven, Event-driven. 4. There are some popular protocols in the transport layer namely STCP (Sensor Transmission Control Protocol), PORT (Price-Oriented Reliable Transport Protocol and PSFQ (pump slow fetch quick). 5. Application layer Responsible for traffic management and provide software for different applications that translate the data in an understandable form or send queries to obtain certain information. Sensor networks deployed in various applications in different fields, for example; military, medical, environment, agriculture fields. It contains a variety of protocols like NNTP, SIP, SSI, DNS, FTP, GOPHER,NFS, NTP, SMTP, SMPP, ANMP and TELNET. The three cross planes or layers are: 1. Power management plane: It is responsible for managing the power level of sensor nodes for processing, sensing and communication. 2. Connection management plane: It is responsible for configuration or reconfiguration of sensor nodes in attempt to establish or maintain network connectivity. 3. Task management plane: It is responsible for distribution of tasks among sensor nodes to prolong network lifetime and improve energy efficiency.
- 8. Diverse Applications of WSNs Environmental Monitoring Detect forest fires. Monitor air and water quality. Track conditions in the Amazon rainforest. Healthcare Monitor patients and provide remote diagnostics. Example: Continuous glucose monitoring. Agriculture Monitor soil moisture and enable precision irrigation. Increased yields by 15%. Smart Homes Automate lighting and enhance security systems. Save 10-12% on heating with smart thermostats.
- 9. Key Benefits of WSNs Real-time Monitoring Immediate data allows timely decisions and quick responses. Cost-Effective Reduced infrastructure and lower labor costs lead to savings. Scalable Easily expandable to cover larger areas with more sensors. Flood warning systems save $10M+ in damages. Agricultural monitoring costs reduced by 40%.
- 10. Challenges and Future Trends Power Consumption Limited battery life is a concern. Current research focuses on energy harvesting techniques. Security Vulnerability to cyber-attacks exists. Advanced encryption methods are being implemented. Data Management Handling large data volumes requires edge computing for local processing. Interoperability The lack of standardized protocols is addressed with open-source platforms and APIs.
- 11. Emerging Technologies Energy Harvesting This technology allows sensors to collect energy from their environment (like sunlight, vibrations, or thermal energy) to power themselves, extending their operational life. Artificial Intelligence (AI) AI enables predictive maintenance. It predicts equipment failure with 90% accuracy. These are being used to analyze the data collected by sensors more effectively, enabling predictive maintenance and smarter decision-making. 5G Integration 5G enhances connectivity and speed. It results in a 10x increase in data transmission rates. The rollout of 5G networks is enhancing the speed and reliability of wireless sensor networks, facilitating real-time data transmission
- 12. Conclusion Wireless sensor networks are transformative technologies that are revolutionizing how we collect and analyze data in real-time. They offer numerous benefits such as enhanced efficiency, cost savings, and improved decision-making across various fields like healthcare, agriculture, and smart cities. With continuous advancements in technology, these networks are becoming more intelligent, energy-efficient, and integrated into our daily lives, paving the way for smarter, more sustainable solutions.
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