An Overview on Wireless Sensor Networks Technology and Evolution
---
paper_title: Sensor networks: an overview

paper_content:

Advances in hardware and wireless network technologies have created low-cost, low-power, multifunctional miniature sensor devices. These devices make up hundreds or thousands of ad hoc tiny sensor nodes spread across a geographical area. These sensor nodes collaborate among themselves to establish a sensing network. A sensor network can provide access to information anytime, anywhere by collecting, processing, analyzing and disseminating data. Thus, the network actively participates in creating a smart environment.
---
paper_title: Overview of sensor networks

paper_content:

Wireless sensor networks could advance many scientific pursuits while providing a vehicle for enhancing various forms of productivity, including manufacturing, agriculture, construction, and transportation.
---
paper_title: Mobile ad-hoc networking

paper_content:

Mobile ad-hoc networks are multihop wireless networks. Wireless communications and the lack of fixed infrastructure generate new research problems compared with fixed multihop networks: Dynamic topologies. Because nodes can move arbitrarily, the network topology, which is typically multihop, can change randomly and rapidly; Bandwidth-constrained, variable capacity, possibly asymmetric links. Wireless links will continue to have significantly lower capacity than wired links and hence congestion is more problematic. Energy-constrained operation. Some, or all nodes in a Mobile ad-hoc network may rely on batteries for energy. For these nodes, power conservation is a critical design criterion. Wireless vulnerabilities and limited physical security. Mobile wireless networks are generally more prone to information and physical security threats than are fixed, hardwired nets. Network technologies for single-hop wireless networks are becoming to appear on the market. The IEEE 802.11 standard is a good platform to implement a one level multi-hop architecture because of its extreme. The Hiperlan standard is the ETSI standard for wireless LANs. Bluetooth technology is an open specification (supported by several hundreds of IT companies) for wireless communication of data and voice. Soon, mobile ad-hoc networks that cover areas of several square kilometres could be built from WLAN technologies such as IEEE 802.11. Furthermore, wireless-network technologies are the building blocks to construct multi-hop mobile ad-hoc networks. In the IETF, the Mobile Ad-hoc NETwork (MANET) working group was set up for developing and evolving mobile ad-hoc network routing specification(s) and introduce them to the Internet Standards track. The goal is to support networks scaling up to hundreds of routers. The step toward a large network (larger than thousand nodes) consisting of nodes with limited resources is not straightforward and presents many challenges that are still to be solved in areas such as: highcapacity wireless technologies, configuration management, addressing, routing, location management, interoperability, and security. The minitrack presents six papers related to the design, modeling and performance evaluation of architectures and
---
paper_title: Designs Wireless Sensor Network Designs

paper_content:

Preface About the Author 1. Networked Embedded Systems 2. Smart Sensor Networks 3. Power-Aware Wireless Sensor Networks 4. Routing in Wireless Sensor Networks 5. Distributed Sensor Networks 6. Clustering Techniques in Wireless Sensor Networks 7. Security Protocols for Wireless Sensor Networks 8. Operating Systems for Embedded Applications 9. Network Support for Embedded Applications 10. Applications of Wireless Sensor Networks References Index
---
paper_title: An overview of Wireless Sensor Network and applications

paper_content:

Wireless Sensor Networks represent a new generation of real-time embedded systems with significantly different communication constraints from the traditional networked systems. This paper first discusses about the hardware platforms and secondly about the software platform. Then detailed information about networking and applications of the Wireless Sensor Networks is outlined. Lastly, this paper provides the future application of the wireless sensor networks for the laboratory mice.
---
paper_title: Protocols for self-organization of a wireless sensor network

paper_content:

We present a suite of algorithms for self-organization of wireless sensor networks in which there is a scalably large number of mainly static nodes with highly constrained energy resources. The protocols further support slow mobility by a subset of the nodes, energy-efficient routing, and formation of ad hoc subnetworks for carrying out cooperative signal processing functions among a set of the nodes.
---
paper_title: Message-efficient in-network location management in a multi-sink wireless sensor network

paper_content:

A wireless sensor network consists of many tiny sensor nodes. The distributed memory spaces of sensors can be considered as a large distributed database, in which one can conduct in-network data processing. This paper considers a sensor network used for object tracking where distributed location updates and queries are performed inside the network. Although this issue has been intensively studied for cellular networks, the same problem in sensor networks has very different characteristics. In this paper, we propose an efficient location management scheme for object tracking in a multi-sink sensor network where users can inquire the locations of objects via any sink in the network. A message-efficient algorithm that describes how to perform location updates and queries is proposed. Furthermore, two distributed virtual tree construction algorithms are also presented. The goal is to reduce the overall update and query cost. The efficiency of the proposed algorithms is evaluated and verified by simulations.
---
paper_title: Sensor networks: an overview

paper_content:

Advances in hardware and wireless network technologies have created low-cost, low-power, multifunctional miniature sensor devices. These devices make up hundreds or thousands of ad hoc tiny sensor nodes spread across a geographical area. These sensor nodes collaborate among themselves to establish a sensing network. A sensor network can provide access to information anytime, anywhere by collecting, processing, analyzing and disseminating data. Thus, the network actively participates in creating a smart environment.
---
paper_title: Overview of sensor networks

paper_content:

Wireless sensor networks could advance many scientific pursuits while providing a vehicle for enhancing various forms of productivity, including manufacturing, agriculture, construction, and transportation.
---
paper_title: Designs Wireless Sensor Network Designs

paper_content:

Preface About the Author 1. Networked Embedded Systems 2. Smart Sensor Networks 3. Power-Aware Wireless Sensor Networks 4. Routing in Wireless Sensor Networks 5. Distributed Sensor Networks 6. Clustering Techniques in Wireless Sensor Networks 7. Security Protocols for Wireless Sensor Networks 8. Operating Systems for Embedded Applications 9. Network Support for Embedded Applications 10. Applications of Wireless Sensor Networks References Index
---
paper_title: An overview of Wireless Sensor Network and applications

paper_content:

Wireless Sensor Networks represent a new generation of real-time embedded systems with significantly different communication constraints from the traditional networked systems. This paper first discusses about the hardware platforms and secondly about the software platform. Then detailed information about networking and applications of the Wireless Sensor Networks is outlined. Lastly, this paper provides the future application of the wireless sensor networks for the laboratory mice.
---
paper_title: Protocols for self-organization of a wireless sensor network

paper_content:

We present a suite of algorithms for self-organization of wireless sensor networks in which there is a scalably large number of mainly static nodes with highly constrained energy resources. The protocols further support slow mobility by a subset of the nodes, energy-efficient routing, and formation of ad hoc subnetworks for carrying out cooperative signal processing functions among a set of the nodes.
---
paper_title: Vital Sign Monitoring System with Life Emergency Event Detection using Wireless Sensor Network

paper_content:

A distributed healthcare monitoring system prototype for clinical and trauma patients, is to be developed, using wireless sensor network node. The proposed system aims to measure various vital physiological health parameters like ECG and body temperature, of patients and elderly persons and transfer his/her health status wirelessly in Ad-hoc network, to remote base station which is connected to a hospital's main Server, using wireless sensor node. Main server shows information of sensor node which transfer presently vital data and if an abnormal ECG activity is encounter, the server will store 1 minute of the ECG-recording and then transmit the recording to PDA and standard PC as a Clinical Diagnostic Station(CDS). Server can calculate Heart Rate(HR) and variation in the R-R interval and if desired by doctor, averaged values together with maximum and minimum values are calculated every on minute.
---
paper_title: A Wireless, Passive Embedded Sensor for Real-Time Monitoring of Water Content in Civil Engineering Materials

paper_content:

A wireless, passive embedded sensor was applied for real-time monitoring of water content in civil engineering materials such as sands, subgrade soils, and concrete materials. The sensor, which comprised of a planar inductor-capacitor (LC) circuit, was embedded in test samples so that the internal water content of the samples could be remotely measured with a loop antenna by tracking the changes in the sensor's resonant frequency. Since the dielectric constant of water was much higher compared with that of the test samples, the presence of water in the samples increased the capacitance of the LC circuit (capacitance of the capacitor was proportional to the dielectric constant of the medium between its electrodes), thus decreasing the sensor's resonant frequency. Using the described sensor, a study was conducted to investigate the drying rate of sand samples of different grain sizes. A study was also conducted to measure the curing rate of a portland cement concrete slab during casting, and its drying rate after it has been soaked in water. The described sensor technology can be applied for long-term monitoring of localized water content inside soils and sands to understand the environmental health in these media. In addition, this sensor will be useful for monitoring water content within concrete supports and road pavements. The measurement of water content is important for civil engineering infrastructure since excess water may hasten their degradation.
---
paper_title: Human Tracking With Wireless Distributed Pyroelectric Sensors

paper_content:

This paper presents a wireless pyroelectric sensor system, composed of sensing modules (slaves), a synchronization and error rejection module (master), and a data fusion module (host), to perform human tracking. The computation workload distribution among slave, master, and host is investigated. The performances and costs of different signal-processing and target-tracking algorithms are discussed. A prototype system is described containing pyroelectric sensor modules that are able to detect the angular displacement of a moving thermal target. Fresnel lens arrays are used to modulate the sensor field of view. The sensor system has been used to track a single human target
---
paper_title: Distributed Environmental Monitoring Using Random Sensor Networks

paper_content:

We present a distributed algorithm for environmental monitoring of a scalar field (such as temperature, intensity of light, atmospheric pressure, etc.) using a random sensor network.We derive an error estimate, discuss the average complexity of the algorithm, and present some simulation results.
---
paper_title: Energy-efficient event detection in 3D wireless sensor networks

paper_content:

Event detection techniques are crucial for environmental monitoring and object tracking applications in wireless sensor networks. Event detection requires sensor readings to be collected from multiple sensors, and as sensors have limited resources, their readings should be retrieved efficiently. Existing aggregation-based event detection methods, however, require all sensors in the network to transmit their readings, which results in high energy consumption for the network. We propose an energy-efficient event detection technique for estimating the state of the whole environment based on only some of the sensor readings and use a contour map to represent the outline of the environment. To detect events in 3D environments, we modify an existing 2D contour mapping algorithm, extending it for 3D environments. By simulation, we show how our event detection technique is more energy-efficient than existing solutions that take readings from all sensors. We evaluated our method from the point of energy efficiency and found that it improves the energy efficiency of event detection in 3D wireless sensor networks.
---
paper_title: Cooperative Diversity in Wireless Sensor Networks

paper_content:

A planar sensor for determining a chemical parameter of a sample, includes a substrate whose surface is at least partly plane and is provided with at least one potentiometric or amperometric and, possibly, an optical transducer, and one or more biochemical components. The transducer and the biochemical component are provided on the surface of the substrate, or at least part of the surface, as a sensor spot, and a cover membrane surrounding this sensor spot, is heat welded to the surface of the substrate. Those sensor spots that include a potentiometric or amperometric transducer are in contact with a strip conductor attached to the plane surface of the substrate and the thermal seal of the cover membrane is interrupted where the conducting strips lead away from the sensor spots.
---
paper_title: Energy efficiency of dense wireless sensor networks: to cooperate or not to cooperate

paper_content:

Decentralized detection in a network of wireless sensor nodes involves the fusion of information about a phenomenon of interest (PoI) from geographically dispersed nodes. In this paper, we investigate the problem of binary decentralized detection in a dense and randomly deployed wireless sensor network (WSN), whereby the communication channels between the nodes and the fusion center are bandwidth-constrained. We consider a scenario in which sensor observations, conditioned on the alternate hypothesis, are independent but not identically distributed across the sensor nodes. We compare two different fusion architectures, namely, the parallel fusion architecture (PFA) and the cooperative fusion architecture (CFA), for such bandwidth-constrained WSNs, where each sensor node is restricted to send a I-bit information to the fusion center. For each architecture, we derive expression for the probability of decision error at the fusion center. We propose a consensus flooding protocol for CFA and analyze its average energy consumption. We analyze the effects of PoI intensity, realistic link models, consensus flooding protocol, and network connectivity on the system reliability and average energy consumption for both fusion architectures. We demonstrate that a trade-off exists among spatial diversity gain, average energy consumption, delivery ratio of the consensus flooding protocol, network connectivity, node density, and Poll intensity in CFA. We then provide insight into the design of cooperative WSNs.
---
paper_title: Mathematical Evaluation of Environmental Monitoring Estimation Error through Energy-Efficient Wireless Sensor Networks

paper_content:

In this paper, the estimation of a scalar field over a bidimensional scenario (e.g., the atmospheric pressure in a wide area) through a self-organizing wireless sensor network (WSN) with energy constraints is investigated. The sensor devices (denoted as nodes) are randomly distributed; they transmit samples to a supervisor by using a clustered network. This paper provides a mathematical framework to analyze the interdependent aspects of WSN communication protocol and signal processing design. Channel modelling and connectivity issues, multiple access control and routing, and the role of distributed digital signal processing (DDSP) techniques are accounted for. The possibility that nodes perform DDSP is studied through a distributed compression technique based on signal resampling. The DDSP impact on network energy efficiency is compared through a novel mathematical approach to the case where the processing is performed entirely by the supervisor. The trade-off between energy conservation (i.e., network lifetime) and estimation error is discussed and a design criterion is proposed as well. Comparison to simulation outcomes validates the model. As an example result, the required node density is found as a trade-off between estimation quality and network lifetime for different system parameters and scalar field characteristics. It is shown that both the DDSP technique and the MAC protocol choice have a relevant impact on the performance of a WSN.
---
paper_title: A New Low-Complexity User Tracking Algorithm for WLAN-Based Positioning Systems

paper_content:

We propose a new low-complexity tracking algorithm inspired by the Fano's sequential decoding algorithm for the position tracking of a user in a WLAN-based indoor localization system. The positioning infrastructure consists of a IEEE 802.11 wireless LAN and of a radio map of the indoor environment, which is available to the user. The position estimation is performed comparing the signal strength received by the user's network card interface to the signal strength values stored in the radio map. By introducing a tracking algorithm, we improve the accuracy of the system, by reducing the number of position estimates which are less probable or impossible for a given environment topology.
---
paper_title: Mobile ad-hoc networking

paper_content:

Mobile ad-hoc networks are multihop wireless networks. Wireless communications and the lack of fixed infrastructure generate new research problems compared with fixed multihop networks: Dynamic topologies. Because nodes can move arbitrarily, the network topology, which is typically multihop, can change randomly and rapidly; Bandwidth-constrained, variable capacity, possibly asymmetric links. Wireless links will continue to have significantly lower capacity than wired links and hence congestion is more problematic. Energy-constrained operation. Some, or all nodes in a Mobile ad-hoc network may rely on batteries for energy. For these nodes, power conservation is a critical design criterion. Wireless vulnerabilities and limited physical security. Mobile wireless networks are generally more prone to information and physical security threats than are fixed, hardwired nets. Network technologies for single-hop wireless networks are becoming to appear on the market. The IEEE 802.11 standard is a good platform to implement a one level multi-hop architecture because of its extreme. The Hiperlan standard is the ETSI standard for wireless LANs. Bluetooth technology is an open specification (supported by several hundreds of IT companies) for wireless communication of data and voice. Soon, mobile ad-hoc networks that cover areas of several square kilometres could be built from WLAN technologies such as IEEE 802.11. Furthermore, wireless-network technologies are the building blocks to construct multi-hop mobile ad-hoc networks. In the IETF, the Mobile Ad-hoc NETwork (MANET) working group was set up for developing and evolving mobile ad-hoc network routing specification(s) and introduce them to the Internet Standards track. The goal is to support networks scaling up to hundreds of routers. The step toward a large network (larger than thousand nodes) consisting of nodes with limited resources is not straightforward and presents many challenges that are still to be solved in areas such as: highcapacity wireless technologies, configuration management, addressing, routing, location management, interoperability, and security. The minitrack presents six papers related to the design, modeling and performance evaluation of architectures and
---
paper_title: Protocols for self-organization of a wireless sensor network

paper_content:

We present a suite of algorithms for self-organization of wireless sensor networks in which there is a scalably large number of mainly static nodes with highly constrained energy resources. The protocols further support slow mobility by a subset of the nodes, energy-efficient routing, and formation of ad hoc subnetworks for carrying out cooperative signal processing functions among a set of the nodes.
---
paper_title: Area Throughput of an IEEE 802.15.4 Based Wireless Sensor Network

paper_content:

In this paper we present a mathematical model to evaluate the performance of an IEEE 802.15.4 based multi-sink Wireless Sensor Network (WSN). Both sensors and sinks are assumed to be Poisson distributed in a given finite domain. Sinks send periodic and synchronous queries, and each sensor transmits its sample to a sink, selected among those that are audible. The IEEE 802.15.4 Multiple Access Control (MAC) protocol is used by sensors to access the channel: both Beacon-Enabled and Non Beacon-Enabled modes are considered. Our aim is to describe how the Area Throughput , defined as the amount of samples per unit of time successfully transmitted to the sinks from the given area, depends on the density of sensors and the query interval. We jointly account for MAC issues (i.e. packet collisions) and connectivity aspects (i.e. network topology, power losses and radio channel behaviour). Performance is evaluated by varying the traffic offered to the network (i.e. the number of sensors deployed), the packet size, the number of Guaranteed Time Slots allocated, and the Superframe Order. A comparison between results obtained in the Beacon-Enabled and the Non Beacon-Enabled cases is also provided, showing how the Area Throughput can be optimised.
---
paper_title: Collaborative Signal and Information Processing: An Information Directed Approach

paper_content:

This paper describes information-based approaches to processing and organizing spatially distributed, multimodal sensor data in a sensor network. Energy-constrained networked sensing systems must rely on collaborative signal and information processing (CSIP) to dynamically allocate resources, maintain multiple sensing foci, and attend to new stimuli of interest, all based on task requirements and resource constraints. Target tracking is an essential capability for sensor networks and is used as a canonical problem for studying information organization problems in CSIP. After formulating a CSIP tracking problem in a distributed constrained optimization framework, the paper describes information-driven sensor query and other techniques for tracking individual targets as well as combinatorial tracking problems such as counting targets. Results from simulations and experimental implementations have demonstrated that these information-based approaches are scalable and make efficient use of scarce sensing and communication resources.
---
paper_title: Area Throughput and Energy Consumption for Clustered Wireless Sensor Networks

paper_content:

In this paper we present a mathematical approach to evaluate the area throughput and the energy consumption of a multi-sink Wireless Sensor Network (WSN). The WSN is organised into clusters, with one sink per cluster collecting data from sensors. A small variation of the Thomas point process is used to model sensors and sinks positions in the target area. We denote as area throughput the amount of samples per second successfully transmitted to the sinks. Both area throughput and energy consumption are strictly related to connectivity and MAC issues. The aim of this work is to devise a mathematical model that takes MAC and connectivity issues into account, under a common framework. We study the behavior of these two performance metrics when varying the target rate, defined as the maximum number of samples the network was deployed to deliver. Results show that a tradeoff between the area throughput and the energy consumption must be found. Finally, the impact of different sensors and sinks distributions on the area throughput is evaluated.
---
paper_title: Mathematical Evaluation of Environmental Monitoring Estimation Error through Energy-Efficient Wireless Sensor Networks

paper_content:

In this paper, the estimation of a scalar field over a bidimensional scenario (e.g., the atmospheric pressure in a wide area) through a self-organizing wireless sensor network (WSN) with energy constraints is investigated. The sensor devices (denoted as nodes) are randomly distributed; they transmit samples to a supervisor by using a clustered network. This paper provides a mathematical framework to analyze the interdependent aspects of WSN communication protocol and signal processing design. Channel modelling and connectivity issues, multiple access control and routing, and the role of distributed digital signal processing (DDSP) techniques are accounted for. The possibility that nodes perform DDSP is studied through a distributed compression technique based on signal resampling. The DDSP impact on network energy efficiency is compared through a novel mathematical approach to the case where the processing is performed entirely by the supervisor. The trade-off between energy conservation (i.e., network lifetime) and estimation error is discussed and a design criterion is proposed as well. Comparison to simulation outcomes validates the model. As an example result, the required node density is found as a trade-off between estimation quality and network lifetime for different system parameters and scalar field characteristics. It is shown that both the DDSP technique and the MAC protocol choice have a relevant impact on the performance of a WSN.
---
paper_title: Area Throughput for CSMA based Wireless Sensor Networks

paper_content:

In this paper we present a mathematical approach to evaluate the area throughput of a multi-sink wireless sensor network (WSN), where nodes transmit their packets to a sink, selected among many. Sensors and sinks are both Poisson distributed in a bounded domain. A carrier sensing multiple access (CSMA) based protocol is used by nodes to access the channel. We denote as area throughput the amount of samples per second successfully transmitted to the sinks. This performance metric is strictly related to both connectivity and MAC issues: it depends, in fact, on the probability that a given sensor node is not isolated and that it succeeds in transmitting its packet (i.e., the packet does not collide). The aim of this work is to devise a mathematical model that takes CSMA and connectivity issues into account under a joint approach. Through this model some network optimisation strategies could be derived. As an example, sensors could perform an aggregation procedure, responding sporadically to queries with a single packet composed of all samples taken since the previous transmission. Our model allows the evaluation of the optimum size of the packet that should be transmitted, so that the area throughput is maximised. Finally, the effects of the connectivity on the area throughput are evaluated.
---
paper_title: A mathematical model for performance of IEEE 802.15.4 beacon-enabled mode

paper_content:

In this paper a Personal Area Network (PAN) composed of multiple nodes, which transmit data to the PAN coordinator through the beacon-enabled mode of the IEEE 802.15.4 Medium Access Control (MAC) protocol, is considered. Upon reception of the beacon transmitted by the PAN coordinator, the nodes transmit their packets using the slotted Carrier Sense Multiple Access with Collision Avoidance algorithm defined by the standard. A mathematical model to describe the access delay statistics and the probability of packet successful reception, is provided. Performance is evaluated by changing the number of nodes, the superframe order and the packet size. The mathematical model is validated through simulation results. A comparison in terms of success probability and throughput with the non beacon-enabled mode of IEEE 802.15.4, is also provided.
---
paper_title: Performance Analysis of IEEE 802.15.4 Non Beacon-Enabled Mode

paper_content:

In this paper, an analytical model for the non beacon-enabled mode of the IEEE 802.15.4 medium access control (MAC) protocol is provided. A wireless sensor network (WSN) composed of nodes, which transmit data to a sink through direct links, is considered. Upon reception of a query from the sink, the nodes transmit their packets by using the carrier-sense multiple access with collision-avoidance algorithm defined by IEEE 802.15.4. Our mathematical model allows the evaluation of the statistical distribution of the traffic generated by the nodes. In particular, the probability that a node succeeds when accessing the channel, and that the final sink receives a packet coming from whatever node, is derived. The results show how the distribution of traffic changes when different loads are offered to the network. Moreover, the model allows the evaluation of the optimum size a packet should have so that the success probability for its transmission is maximized. The results are validated through simulations. The model differs from those previously published by other authors in the literature as it precisely follows the MAC procedure defined by the standard in the context of the WSN scenario described.
---
paper_title: Impulse radio: how it works

paper_content:

Impulse radio, a form of ultra-wide bandwidth (UWB) spread-spectrum signaling, has properties that make it a viable candidate for short-range communications in dense multipath environments. This paper describes the characteristics of impulse radio using a modulation format that can be supported by currently available impulse signal technology and gives analytical estimates of its multiple-access capability under ideal multiple-access channel conditions.
---
paper_title: Ranging With Ultrawide Bandwidth Signals in Multipath Environments

paper_content:

Over the coming decades, high-definition situationally-aware networks have the potential to create revolutionary applications in the social, scientific, commercial, and military sectors. Ultrawide bandwidth (UWB) technology is a viable candidate for enabling accurate localization capabilities through time-of-arrival (TOA)-based ranging techniques. These techniques exploit the fine delay resolution property of UWB signals by estimating the TOA of the first signal path. Exploiting the full capabilities of UWB TOA estimation can be challenging, especially when operating in harsh propagation environments, since the direct path may not exist or it may not be the strongest. In this paper, we first give an overview of ranging techniques together with the primary sources of TOA error (including propagation effects, clock drift, and interference). We then describe fundamental TOA bounds (such as the Cramer-Rao bound and the tighter Ziv-Zakai bound) in both ideal and multipath environments. These bounds serve as useful benchmarks in assessing the performance of TOA estimation techniques. We also explore practical low-complexity TOA estimation techniques and analyze their performance in the presence of multipath and interference using IEEE 802.15.4a channel models as well as experimental data measured in indoor residential environments.
---

Title: An Overview on Wireless Sensor Networks Technology and Evolution

Section 1: Introduction
Description 1: This section introduces wireless sensor networks (WSNs), their increased interest from both industrial and research perspectives, and a summary of the paper's content structure.

Section 2: Wireless Sensor Networks
Description 2: Define WSNs and discuss their architecture, including single-sink and multiple-sink scenarios, and the protocol considerations for better network performance.

Section 3: Applications of WSNs
Description 3: Categorize the various possible applications of WSNs, emphasizing the relationship between application requirements and technology selection.

Section 4: Applications Classification
Description 4: Provide a classification of WSN applications based on the type of data gathered, distinguishing between event detection (ED) and spatial process estimation (SPE).

Section 5: Examples of Application Requirements
Description 5: Discuss how system requirements vary significantly across different applications and emphasize the importance of energy efficiency, connectivity, and communication protocols.

Section 6: Main Features in Wireless Sensor Networks Design
Description 6: Discuss the main features critical to WSN design, including scalability, self-organization, self-healing, energy efficiency, and the fundamental differences between WSNs and wireless ad hoc networks.

Section 7: Example of Wireless Sensor Network Design
Description 7: Present a case study showcasing a self-organizing single-sink WSN for environmental monitoring, addressing connectivity, MAC issues, and distributed digital signal processing techniques.

Section 8: Case Study: Environmental Monitoring
Description 8: Describe a low-cost hardware and software WSN test-bed developed for agricultural monitoring, including its design, energy efficiency, and operational details.

Section 9: IEEE 802.15.4 Physical Layer
Description 9: Present the 802.15.4 core system, its operation in different unlicensed bands, transmission range, and the importance of low rate and low duty cycle for energy efficiency.

Section 10: IEEE 802.15.4 MAC Layer
Description 10: Explain the protocol based on the CSMA/CA algorithm, including its different operational modes (beacon-enabled and non beacon-enabled) and their respective channel access mechanisms.

Section 11: IEEE 802.15.4 Network Topologies and Operational Modes
Description 11: Discuss multihop self-organizing network topologies and the types of devices (Full Function Device and Reduced Function Device), including star and peer-to-peer topologies.

Section 12: The IEEE 802.15.4 Topology Formation Procedure
Description 12: Outline the PAN coordinator's channel selection process, the association procedure for other devices, and the scan types (passive and active) during the association phase.

Section 13: Zigbee and the Tree-Based Topology
Description 13: Describe the Zigbee standard, its mesh network capabilities, and the beacon-enabled tree-based topology, including beacon scheduling and coordination among nodes in the tree.

Section 14: 6LowPan
Description 14: Compare 6LowPan and Zigbee standards, emphasizing IP interoperability, address assignment, network management, and use cases for each technology.

Section 15: Performance Trends of 802.15.4 Based WSNs
Description 15: Provide numerical results on throughput and energy consumption for different network topologies using 802.15.4, including point-to-point, multi-hop, and star topologies.

Section 16: Other Technologies
Description 16: Discuss the features and applications of various other WSN technologies such as Ultrawide Bandwidth, Bluetooth, Z-Wave, Bluetooth Low Energy, and ANT Technology.

Section 17: Future Research Directions and Projects
Description 17: Explore future WSN research directions influenced by both application-agnostic trends (e.g., cognitive radio networking, MAC and network layer protocols) and market-driven trends (e.g., building monitoring, body area networks, vehicular applications).

Section 18: Conclusions
Description 18: Summarize the most relevant issues in WSNs from application, design, and technology viewpoints, and provide insights into future research and technological developments.