Routing protocols in wireless sensor networks face several unique challenges compared to other wireless networks. The document discusses these challenges and provides an overview of common routing protocol approaches in WSNs, including flat routing protocols like SPIN and Directed Diffusion, hierarchical routing protocols like LEACH, and location-based routing protocols. It also covers routing design issues specific to WSNs such as energy efficiency, data delivery models, fault tolerance, and quality of service.
This document discusses power aware routing protocols for wireless sensor networks. It begins by describing wireless sensor networks and how they are used to monitor environmental conditions. It then classifies routing protocols for sensor networks based on their functioning, node participation style, and network structure. Specific examples are provided for different types of routing protocols, including LEACH, TEEN, APTEEN, SPIN, Rumor Routing, and PEGASIS. Chain-based and clustering routing protocols are also summarized.
This document discusses different types of routing protocols for mobile ad hoc networks. It begins by classifying routing protocols into four categories: proactive (table-driven), reactive (on-demand), hybrid, and geographic location-assisted. It then provides more details on proactive protocols like DSDV, and reactive protocols like DSR and AODV. For DSDV, it describes how routing tables are regularly exchanged and updated when link breaks occur. For DSR and AODV, it explains how routes are discovered on-demand via route requests and replies. Key differences between DSR and AODV are also summarized.
Directed diffusion for wireless sensor networkingHabibur Rahman
This document summarizes the key ideas of the "Directed Diffusion for Wireless Sensor Networking" paper. It introduces directed diffusion as a data-centric paradigm for wireless sensor networks that is designed for robustness, scalability, and energy efficiency. The core concepts of directed diffusion are interests, data, gradients, and reinforcement, which work together to efficiently route queries to sensor data in the network. Through localized interactions and data aggregation, directed diffusion is shown to significantly reduce energy consumption compared to flooding-based approaches in wireless sensor networks.
The document discusses on-demand driven reactive routing protocols. It provides an overview of table-driven vs on-demand routing protocols and describes two popular on-demand protocols - Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector Routing (AODV) in detail. DSR uses source routing by adding the complete route to packet headers. AODV maintains routing tables at nodes and relies on dynamically establishing next hop information for routes.
Sensor Protocols for Information via Negotiation (SPIN)rajivagarwal23dei
Wireless sensor networks consist of large numbers of sensor nodes that monitor parameters and communicate wirelessly. The SPIN protocol family was developed to address the limitations of sensor nodes, particularly their limited energy, computation, and communication capabilities. SPIN uses meta-data negotiation and resource awareness to disseminate data between nodes more efficiently than flooding protocols. SPIN-1 is a simple three-stage handshake protocol that reduces energy costs. SPIN-2 builds upon SPIN-1 with an additional energy conservation heuristic to further prolong network lifetime. Evaluation shows SPIN consumes significantly less energy than flooding for data dissemination in wireless sensor networks.
The document discusses schedule-based MAC protocols for wireless sensor networks. It begins with a review of previous concepts and then discusses key schedule-based protocols including LEACH, SPIN, S-MAC, and TRAMA. The document emphasizes that schedule-based protocols explicitly assign transmission timeslots to nodes to avoid collisions and allow nodes to sleep at other times, reducing idle listening and improving energy efficiency compared to contention-based protocols. Time synchronization is necessary for schedule-based protocols to function properly.
The document summarizes key points from an 8th lecture on wireless sensor networks. It discusses various medium access control (MAC) protocols that control when nodes can access a shared wireless medium. These include contention-based protocols like MACA that use RTS/CTS handshaking and schedule-based protocols with fixed or dynamic scheduling. It also describes energy-efficient MAC protocols for low data rate sensor networks like S-MAC, T-MAC, and preamble sampling that increase sleep time to reduce energy use through synchronized sleep schedules or long preambles.
The document discusses several routing protocols for mobile ad hoc networks:
- DSR allows nodes to cache and share routing information for more efficient routing but has larger packet headers due to source routing. AODV uses only next hop information, keeping routing tables smaller.
- Both protocols use route discovery and maintenance, but AODV proactively refreshes routes while DSR reacts to failures. AODV also uses sequence numbers to prevent loops and choose fresher routes.
- Overall, DSR is better for networks where routes change infrequently while AODV scales better and maintains only active routes, at the cost of higher routing overhead during route discovery. Security remains a challenge for both protocols.
This document discusses power aware routing protocols for wireless sensor networks. It begins by describing wireless sensor networks and how they are used to monitor environmental conditions. It then classifies routing protocols for sensor networks based on their functioning, node participation style, and network structure. Specific examples are provided for different types of routing protocols, including LEACH, TEEN, APTEEN, SPIN, Rumor Routing, and PEGASIS. Chain-based and clustering routing protocols are also summarized.
This document discusses different types of routing protocols for mobile ad hoc networks. It begins by classifying routing protocols into four categories: proactive (table-driven), reactive (on-demand), hybrid, and geographic location-assisted. It then provides more details on proactive protocols like DSDV, and reactive protocols like DSR and AODV. For DSDV, it describes how routing tables are regularly exchanged and updated when link breaks occur. For DSR and AODV, it explains how routes are discovered on-demand via route requests and replies. Key differences between DSR and AODV are also summarized.
Directed diffusion for wireless sensor networkingHabibur Rahman
This document summarizes the key ideas of the "Directed Diffusion for Wireless Sensor Networking" paper. It introduces directed diffusion as a data-centric paradigm for wireless sensor networks that is designed for robustness, scalability, and energy efficiency. The core concepts of directed diffusion are interests, data, gradients, and reinforcement, which work together to efficiently route queries to sensor data in the network. Through localized interactions and data aggregation, directed diffusion is shown to significantly reduce energy consumption compared to flooding-based approaches in wireless sensor networks.
The document discusses on-demand driven reactive routing protocols. It provides an overview of table-driven vs on-demand routing protocols and describes two popular on-demand protocols - Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector Routing (AODV) in detail. DSR uses source routing by adding the complete route to packet headers. AODV maintains routing tables at nodes and relies on dynamically establishing next hop information for routes.
Sensor Protocols for Information via Negotiation (SPIN)rajivagarwal23dei
Wireless sensor networks consist of large numbers of sensor nodes that monitor parameters and communicate wirelessly. The SPIN protocol family was developed to address the limitations of sensor nodes, particularly their limited energy, computation, and communication capabilities. SPIN uses meta-data negotiation and resource awareness to disseminate data between nodes more efficiently than flooding protocols. SPIN-1 is a simple three-stage handshake protocol that reduces energy costs. SPIN-2 builds upon SPIN-1 with an additional energy conservation heuristic to further prolong network lifetime. Evaluation shows SPIN consumes significantly less energy than flooding for data dissemination in wireless sensor networks.
The document discusses schedule-based MAC protocols for wireless sensor networks. It begins with a review of previous concepts and then discusses key schedule-based protocols including LEACH, SPIN, S-MAC, and TRAMA. The document emphasizes that schedule-based protocols explicitly assign transmission timeslots to nodes to avoid collisions and allow nodes to sleep at other times, reducing idle listening and improving energy efficiency compared to contention-based protocols. Time synchronization is necessary for schedule-based protocols to function properly.
The document summarizes key points from an 8th lecture on wireless sensor networks. It discusses various medium access control (MAC) protocols that control when nodes can access a shared wireless medium. These include contention-based protocols like MACA that use RTS/CTS handshaking and schedule-based protocols with fixed or dynamic scheduling. It also describes energy-efficient MAC protocols for low data rate sensor networks like S-MAC, T-MAC, and preamble sampling that increase sleep time to reduce energy use through synchronized sleep schedules or long preambles.
The document discusses several routing protocols for mobile ad hoc networks:
- DSR allows nodes to cache and share routing information for more efficient routing but has larger packet headers due to source routing. AODV uses only next hop information, keeping routing tables smaller.
- Both protocols use route discovery and maintenance, but AODV proactively refreshes routes while DSR reacts to failures. AODV also uses sequence numbers to prevent loops and choose fresher routes.
- Overall, DSR is better for networks where routes change infrequently while AODV scales better and maintains only active routes, at the cost of higher routing overhead during route discovery. Security remains a challenge for both protocols.
This document summarizes geographical routing in wireless sensor networks. It begins with an introduction to geographic routing protocols, which route packets based on the geographic position of nodes rather than their network addresses. It then discusses several specific geographic routing protocols, including Greedy Perimeter Stateless Routing (GPSR) and Geographical and Energy Aware Routing (GEAR). The document also covers topics like how nodes obtain location information, security issues in geographic routing like the Sybil attack, and concludes that geographic routing can enable scalable and energy-efficient routing in wireless sensor networks.
Lecture 23 27. quality of services in ad hoc wireless networksChandra Meena
The document discusses quality of service (QoS) in mobile ad hoc networks (MANETs). It covers several key topics:
1) The challenges of providing QoS in MANETs due to their dynamic and decentralized nature.
2) Different approaches to QoS classification and provisioning at various network layers. This includes MAC layer solutions like IEEE 802.11e and network layer solutions like QoS-aware routing protocols.
3) Specific QoS routing protocols discussed, including ticket-based, predictive location-based, and trigger-based distributed protocols.
Design Issues and Challenges in Wireless Sensor NetworksKhushbooGupta145
Wireless Sensor Networks (WSNs) are composed self-organized wireless ad hoc networks which comprise of a large number of resource constrained sensor nodes. The major areas of research in WSN is going on hardware, and operating system of WSN, deployment, architecture, localization, synchronization, programming models, data aggregation and dissemination, database querying, architecture, middleware, quality of service and security. This paper study highlights ongoing research activities and issues that affect the design and performance of Wireless Sensor Network.
The document summarizes several routing protocols used in wireless networks. It discusses both table-driven protocols like DSDV and on-demand protocols like AODV. It provides details on how each protocol performs routing and maintains routes. It also outlines some advantages and disadvantages of protocols like DSDV, AODV, DSR, and TORA.
This document discusses localization techniques in wireless sensor networks (WSNs). It begins with an introduction to WSNs and their applications that require location information. While GPS could provide location data, it is not practical for WSNs due to cost and physical constraints. The document then categorizes localization methods as range-based, which use distance or angle measurements, and range-free, which do not directly measure distance. Specific techniques like time of arrival, received signal strength, and DV-Hop localization are described. The document concludes with classifications of localization methods and topics for future work.
This document discusses localization techniques in wireless sensor networks. It begins with introducing wireless sensor networks and their components. It then discusses the need for localization to track objects within sensor networks. There are two main types of localization schemes - range-based which uses distance or angle measurements, and range-free which uses approximate distance estimates. Examples of range-based techniques include time of arrival, time difference of arrival, received signal strength indicator, and angle of arrival. Range-free techniques include proximity and distance-based localization using hop counts. The document compares the advantages and disadvantages of different localization methods.
The document discusses key issues in designing ad hoc wireless routing protocols including mobility, bandwidth constraints from a shared radio channel, and resource constraints of battery life and processing power. It outlines problems like the hidden and exposed terminal problems that can occur on a shared wireless channel. It also provides ideal characteristics for routing protocols, noting they should be fully distributed, adaptive to topology changes, use minimal flooding, and converge quickly when paths break while minimizing overhead through efficient use of bandwidth and resources.
This document summarizes several reactive routing protocols for mobile ad hoc networks (MANETs). Reactive protocols create routes only when needed by a source. Dynamic Source Routing uses route requests and replies to find paths, while Temporally-Ordered Routing Algorithm builds and maintains a directed acyclic graph rooted at destinations. Some protocols aim to improve quality of service or support real-time data streams through techniques like bandwidth estimation and mobility prediction. Source Routing with Local Recovery reduces overhead by allowing intermediate nodes to perform local error recovery using route caches when possible.
The document discusses the LEACH protocol and DECSA improvement for wireless sensor networks. It describes the two phases of LEACH - the set-up phase where cluster heads are chosen and the steady-state phase where data is transmitted. DECSA considers both distance and residual energy to select cluster heads, forming a three-level hierarchy. DECSA prolongs network lifetime by 31% and reduces energy consumption by 40% compared to the original LEACH protocol.
The document describes two wireless sensor network routing protocols: LEACH and PEGASIS. LEACH uses local processing to reduce global communication and randomly rotates cluster heads to distribute energy load. PEGASIS forms chains between nodes so that each node only communicates with a close neighbor, extending network lifetime compared to LEACH by up to 3 times. Both protocols aim to improve energy efficiency through data aggregation and minimizing transmission distances in wireless sensor networks.
The document discusses clustering protocols in wireless sensor networks (WSNs). It begins by introducing WSNs and their applications. It then describes the main types of communication in WSNs: direct, multi-hop, and using clustering. Several issues with clustering in WSNs are identified, such as selecting cluster heads and handling node mobility. Popular clustering protocols like LEACH are examined, noting their advantages like data aggregation but also limitations such as unsuitability for large networks. Proposed solutions for improving LEACH involve considering energy levels and traffic load when selecting cluster heads.
Mac protocols for ad hoc wireless networks Divya Tiwari
The document discusses MAC protocols for ad hoc wireless networks. It addresses key issues in designing MAC protocols including limited bandwidth, quality of service support, synchronization, hidden and exposed terminal problems, error-prone shared channels, distributed coordination without centralized control, and node mobility. Common MAC protocol classifications and examples are also presented, such as contention-based protocols, sender-initiated versus receiver-initiated protocols, and protocols using techniques like reservation, scheduling, and directional antennas.
SPINS: Security Protocols for Sensor NetworksAbhijeet Awade
This document summarizes the SPINS security protocols for sensor networks. It discusses two protocols: SNEP for basic node-to-base station security and μTESLA for authenticated broadcast. SNEP provides data confidentiality through symmetric encryption and data authentication using message authentication codes. μTESLA provides authentication for broadcast messages through disclosure of symmetric keys along a key chain. The document also gives examples of applications these protocols can enable, such as authenticated routing and pairwise key agreement between nodes.
This document discusses wireless sensor networks and their role in the Internet of Things. It defines sensor networks and their architecture, including sensor nodes that communicate wirelessly to a base station. It outlines challenges for sensor networks like fault tolerance, scalability, and quality of service. It also describes how sensor networks can be integrated into the Internet of Things through different approaches, with the first using a single gateway and later approaches using hybrid networks and access points. Applications of sensor networks in IoT include wearable devices collecting biometric data and communicating it to servers.
ZRP divides routing into intrazone and interzone routing. Intrazone routing uses a proactive approach to route packets within a node's routing zone. Interzone routing uses a reactive approach where the source node sends route requests to peripheral nodes when the destination is outside its zone. The optimal zone radius depends on factors like mobility and query rates, with smaller radii preferred for higher mobility. ZRP aims to reduce routing overhead through techniques like restricting floods and maintaining multiple routes.
Minimize energy per packet (or per bit)
Maximize network lifetime
Routing considering available battery energy
Maximum Total Available Battery Capacity
Minimum Battery Cost Routing (MBCR)
Min– Max Battery Cost Routing (MMBCR)
Conditional Max – Min Battery Capacity Routing (CMMBCR)
Minimize variance in power levels
Minimum Total Transmission Power Routing (MTPR)
The document discusses routing protocols for wireless sensor networks (WSNs). It provides an overview of routing challenges in WSNs, including energy constraints, data delivery models, fault tolerance, and quality of service issues. It then describes two common flat routing protocols for WSNs: SPIN and Directed Diffusion. SPIN uses data negotiation to disseminate information and avoid redundant transmissions. Directed Diffusion establishes interest gradients to route data from sources to a sink based on attribute-value pairs.
Network architecture documents the key differences between ad hoc and sensor networks. Ad hoc networks allow nodes to communicate directly with each other in a peer-to-peer fashion, while sensor networks have dedicated source nodes that sense data and sink nodes that receive the data. Sensor networks also employ in-network processing techniques like data aggregation to reduce energy costs of transmitting all raw data. Routing in wireless sensor networks faces challenges from limited node resources, topology changes, and energy constraints that require routing protocols to be scalable, fault-tolerant and energy-efficient.
This document summarizes geographical routing in wireless sensor networks. It begins with an introduction to geographic routing protocols, which route packets based on the geographic position of nodes rather than their network addresses. It then discusses several specific geographic routing protocols, including Greedy Perimeter Stateless Routing (GPSR) and Geographical and Energy Aware Routing (GEAR). The document also covers topics like how nodes obtain location information, security issues in geographic routing like the Sybil attack, and concludes that geographic routing can enable scalable and energy-efficient routing in wireless sensor networks.
Lecture 23 27. quality of services in ad hoc wireless networksChandra Meena
The document discusses quality of service (QoS) in mobile ad hoc networks (MANETs). It covers several key topics:
1) The challenges of providing QoS in MANETs due to their dynamic and decentralized nature.
2) Different approaches to QoS classification and provisioning at various network layers. This includes MAC layer solutions like IEEE 802.11e and network layer solutions like QoS-aware routing protocols.
3) Specific QoS routing protocols discussed, including ticket-based, predictive location-based, and trigger-based distributed protocols.
Design Issues and Challenges in Wireless Sensor NetworksKhushbooGupta145
Wireless Sensor Networks (WSNs) are composed self-organized wireless ad hoc networks which comprise of a large number of resource constrained sensor nodes. The major areas of research in WSN is going on hardware, and operating system of WSN, deployment, architecture, localization, synchronization, programming models, data aggregation and dissemination, database querying, architecture, middleware, quality of service and security. This paper study highlights ongoing research activities and issues that affect the design and performance of Wireless Sensor Network.
The document summarizes several routing protocols used in wireless networks. It discusses both table-driven protocols like DSDV and on-demand protocols like AODV. It provides details on how each protocol performs routing and maintains routes. It also outlines some advantages and disadvantages of protocols like DSDV, AODV, DSR, and TORA.
This document discusses localization techniques in wireless sensor networks (WSNs). It begins with an introduction to WSNs and their applications that require location information. While GPS could provide location data, it is not practical for WSNs due to cost and physical constraints. The document then categorizes localization methods as range-based, which use distance or angle measurements, and range-free, which do not directly measure distance. Specific techniques like time of arrival, received signal strength, and DV-Hop localization are described. The document concludes with classifications of localization methods and topics for future work.
This document discusses localization techniques in wireless sensor networks. It begins with introducing wireless sensor networks and their components. It then discusses the need for localization to track objects within sensor networks. There are two main types of localization schemes - range-based which uses distance or angle measurements, and range-free which uses approximate distance estimates. Examples of range-based techniques include time of arrival, time difference of arrival, received signal strength indicator, and angle of arrival. Range-free techniques include proximity and distance-based localization using hop counts. The document compares the advantages and disadvantages of different localization methods.
The document discusses key issues in designing ad hoc wireless routing protocols including mobility, bandwidth constraints from a shared radio channel, and resource constraints of battery life and processing power. It outlines problems like the hidden and exposed terminal problems that can occur on a shared wireless channel. It also provides ideal characteristics for routing protocols, noting they should be fully distributed, adaptive to topology changes, use minimal flooding, and converge quickly when paths break while minimizing overhead through efficient use of bandwidth and resources.
This document summarizes several reactive routing protocols for mobile ad hoc networks (MANETs). Reactive protocols create routes only when needed by a source. Dynamic Source Routing uses route requests and replies to find paths, while Temporally-Ordered Routing Algorithm builds and maintains a directed acyclic graph rooted at destinations. Some protocols aim to improve quality of service or support real-time data streams through techniques like bandwidth estimation and mobility prediction. Source Routing with Local Recovery reduces overhead by allowing intermediate nodes to perform local error recovery using route caches when possible.
The document discusses the LEACH protocol and DECSA improvement for wireless sensor networks. It describes the two phases of LEACH - the set-up phase where cluster heads are chosen and the steady-state phase where data is transmitted. DECSA considers both distance and residual energy to select cluster heads, forming a three-level hierarchy. DECSA prolongs network lifetime by 31% and reduces energy consumption by 40% compared to the original LEACH protocol.
The document describes two wireless sensor network routing protocols: LEACH and PEGASIS. LEACH uses local processing to reduce global communication and randomly rotates cluster heads to distribute energy load. PEGASIS forms chains between nodes so that each node only communicates with a close neighbor, extending network lifetime compared to LEACH by up to 3 times. Both protocols aim to improve energy efficiency through data aggregation and minimizing transmission distances in wireless sensor networks.
The document discusses clustering protocols in wireless sensor networks (WSNs). It begins by introducing WSNs and their applications. It then describes the main types of communication in WSNs: direct, multi-hop, and using clustering. Several issues with clustering in WSNs are identified, such as selecting cluster heads and handling node mobility. Popular clustering protocols like LEACH are examined, noting their advantages like data aggregation but also limitations such as unsuitability for large networks. Proposed solutions for improving LEACH involve considering energy levels and traffic load when selecting cluster heads.
Mac protocols for ad hoc wireless networks Divya Tiwari
The document discusses MAC protocols for ad hoc wireless networks. It addresses key issues in designing MAC protocols including limited bandwidth, quality of service support, synchronization, hidden and exposed terminal problems, error-prone shared channels, distributed coordination without centralized control, and node mobility. Common MAC protocol classifications and examples are also presented, such as contention-based protocols, sender-initiated versus receiver-initiated protocols, and protocols using techniques like reservation, scheduling, and directional antennas.
SPINS: Security Protocols for Sensor NetworksAbhijeet Awade
This document summarizes the SPINS security protocols for sensor networks. It discusses two protocols: SNEP for basic node-to-base station security and μTESLA for authenticated broadcast. SNEP provides data confidentiality through symmetric encryption and data authentication using message authentication codes. μTESLA provides authentication for broadcast messages through disclosure of symmetric keys along a key chain. The document also gives examples of applications these protocols can enable, such as authenticated routing and pairwise key agreement between nodes.
This document discusses wireless sensor networks and their role in the Internet of Things. It defines sensor networks and their architecture, including sensor nodes that communicate wirelessly to a base station. It outlines challenges for sensor networks like fault tolerance, scalability, and quality of service. It also describes how sensor networks can be integrated into the Internet of Things through different approaches, with the first using a single gateway and later approaches using hybrid networks and access points. Applications of sensor networks in IoT include wearable devices collecting biometric data and communicating it to servers.
ZRP divides routing into intrazone and interzone routing. Intrazone routing uses a proactive approach to route packets within a node's routing zone. Interzone routing uses a reactive approach where the source node sends route requests to peripheral nodes when the destination is outside its zone. The optimal zone radius depends on factors like mobility and query rates, with smaller radii preferred for higher mobility. ZRP aims to reduce routing overhead through techniques like restricting floods and maintaining multiple routes.
Minimize energy per packet (or per bit)
Maximize network lifetime
Routing considering available battery energy
Maximum Total Available Battery Capacity
Minimum Battery Cost Routing (MBCR)
Min– Max Battery Cost Routing (MMBCR)
Conditional Max – Min Battery Capacity Routing (CMMBCR)
Minimize variance in power levels
Minimum Total Transmission Power Routing (MTPR)
The document discusses routing protocols for wireless sensor networks (WSNs). It provides an overview of routing challenges in WSNs, including energy constraints, data delivery models, fault tolerance, and quality of service issues. It then describes two common flat routing protocols for WSNs: SPIN and Directed Diffusion. SPIN uses data negotiation to disseminate information and avoid redundant transmissions. Directed Diffusion establishes interest gradients to route data from sources to a sink based on attribute-value pairs.
Network architecture documents the key differences between ad hoc and sensor networks. Ad hoc networks allow nodes to communicate directly with each other in a peer-to-peer fashion, while sensor networks have dedicated source nodes that sense data and sink nodes that receive the data. Sensor networks also employ in-network processing techniques like data aggregation to reduce energy costs of transmitting all raw data. Routing in wireless sensor networks faces challenges from limited node resources, topology changes, and energy constraints that require routing protocols to be scalable, fault-tolerant and energy-efficient.
Wireless sensor networks are composed of small, low-cost sensor nodes that are densely deployed to monitor environmental conditions. Each node has sensing, processing and communication capabilities. Sensor networks have many applications including military surveillance, environmental monitoring, health monitoring, smart homes/offices, and inventory management. Routing data efficiently in sensor networks faces challenges due to the large number of nodes, limited energy/resources of nodes, and dynamic network topology changes. Common routing architectures include layered architectures where nodes are organized in layers based on distance from the base station, and clustered architectures where nodes are organized into clusters with cluster heads routing data.
This document discusses wireless sensor networks and routing protocols. It covers several key topics:
1) It describes single-hop and multihop data transmission in wireless sensor networks and the advantages of multihop in increasing network lifetime and reducing interference.
2) It discusses routing challenges in wireless sensor networks due to constraints like energy, bandwidth and changing environments. It also covers routing strategies like proactive, reactive and hybrid routing.
3) It provides details on common routing protocols for wireless sensor networks like flooding, gossiping, SPIN and LEACH, outlining their key mechanisms and advantages/disadvantages. LEACH uses clustering to improve energy efficiency.
The document discusses routing challenges and protocols in wireless sensor networks (WSNs). It covers flooding, hierarchical routing protocols like LEACH, data-centric protocols like directed diffusion, and negotiation-based protocols like SPIN. It also discusses resource constraints in WSNs like limited energy and the need for routing protocols to be energy-efficient. Unique characteristics of WSNs like dynamic topology and varying node densities present new challenges for routing protocol design.
This document provides guidance on writing a research paper, beginning with choosing a topic and developing a thesis statement. It outlines the steps of writing a paper, including selecting and analyzing primary and secondary sources, compiling information, avoiding plagiarism through proper paraphrasing and citation, and including a bibliography. The document emphasizes writing an outline before starting the paper, using multiple credible source types, and thoroughly proofreading the final draft. Research papers require following a process of topic selection, research, organization, citation, and revision to effectively communicate new information and ideas.
This document discusses wireless sensor networks and their architecture. It describes layered and clustered architectures for organizing sensor networks. Layered architectures arrange sensors in layers around a central base station, allowing for short-range transmissions. Clustered architectures organize sensors into clusters headed by cluster heads that can aggregate and transmit data to the base station. The document also introduces protocols like UNPF that implement layered architectures and LEACH that uses clustering to minimize energy use in sensor networks.
Routing protocols are essential for wireless sensor networks to efficiently transmit collected sensor data to data sinks. The document discusses several challenges in designing routing protocols for wireless sensor networks and surveys different routing techniques including flat, hierarchical, and geographic routing. It provides LEACH and PEGASIS as examples of hierarchical routing protocols that use clustering and data aggregation to reduce energy consumption.
The document discusses routing protocols in wireless sensor networks. It outlines several key challenges for routing protocols including node deployment, network dynamics, energy conservation, fault tolerance, scalability, and hardware constraints. It then describes several common routing techniques used in wireless sensor networks, including proactive, reactive, and hybrid path establishment approaches, as well as flat, hierarchical, and location-based network structures. Finally, it discusses different protocol operations such as multipath routing, query-based routing, negotiation-based routing, and supporting quality of service metrics.
Wireless sensor networks consist of distributed sensors that monitor conditions like temperature and sound and transmit data to a central location. They have two types - structured networks which are pre-planned and unstructured which are randomly deployed. The document reviews issues in wireless sensor networks like energy constraints and quality of service. It also discusses network services, internal sensor systems, applications, and communication protocols. Open research areas are identified in localization, coverage, security, cross-layer optimization and mobility support to improve energy efficiency and performance.
This document discusses routing protocols in wireless sensor networks. It begins with an introduction to routing challenges in WSNs such as limited energy, processing, and storage in sensor nodes. It then covers different routing techniques including flat routing protocols like SPIN, directed diffusion, and rumor routing. Hierarchical routing protocols discussed include LEACH, PEGASIS, TEEN, and APTEEN. Finally, it briefly mentions location-based routing and the GEAR protocol.
The document presents a graduate project on efficient data aggregation from polling points in wireless sensor networks. The proposed system called Mobi-Cluster aims to minimize overall network overhead and energy expenditure associated with multi-hop data retrieval while ensuring balanced energy consumption and prolonged network lifetime. This is achieved through building cluster structures consisting of member nodes that route data to assigned cluster heads, and selecting appropriate polling points to act as intermediaries between clusters and a mobile collector. The key stages of the Mobi-Cluster protocol are described as cluster head selection, polling point selection, cluster head attachment to polling points, data aggregation and forwarding to polling points, and communication between polling points and the mobile collector.
Computational intelligence based data aggregation technique in clustered wsnTAIWAN
The document discusses computational intelligence based data aggregation techniques in wireless sensor networks. It begins by introducing the research intentions of integrating computational intelligence techniques with conventional data aggregation to improve efficiency. It then provides background on wireless sensor network architectures, routing protocols, and challenges with data aggregation. Finally, it proposes using techniques like neural networks, genetic algorithms, fuzzy logic, and particle swarm optimization to enable adaptive and distributed data aggregation and fusion in sensor networks.
The document provides an overview of routing protocols in wireless sensor networks. It discusses several categories of routing protocols including data-centric, hierarchical, and location-based. For hierarchical routing protocols, it summarizes LEACH, PEGASIS, HEED, P-LEACH, H-LEACH, and other variants that aim to improve energy efficiency. It provides brief descriptions of how each protocol operates and highlights drawbacks. The document also summarizes several data-centric routing protocols including Directed Diffusion, Rumor Routing, and their limitations.
Wireless sensors networks protocols part 2Rushin Shah
The document discusses routing protocols for wireless sensor networks. It describes why routing protocols are needed in WSNs to efficiently transmit sensor data to data sinks. It outlines several challenges for routing in WSNs, including limited resources, large network scales, dynamic environments, and different data traffic models. The document then examines different routing strategies like proactive, reactive, and hybrid approaches. It also discusses routing techniques that use flat networks, clustering, data-centric approaches, and geographic location-based routing. Flooding and gossiping are presented as common information dissemination techniques with issues like implosion and resource blindness.
Ad hoc & WSN Routing protocols (Geetha) (2).pptxGomathi454280
The document discusses routing protocols and design challenges in wireless sensor networks. It describes how routing protocols select suitable paths for data to travel from source to destination, taking into account the type of network, channel characteristics, and performance metrics. It then lists several routing challenges in WSNs, including difficulties allocating identifiers, redundant data traffic, and limited energy, bandwidth, and storage of sensor nodes. Finally, it discusses key design challenges like energy efficiency, complexity, scalability, delay, robustness, data transmission models, and locating sensor nodes.
Ad hoc & WSN Routing protocols (Geetha) (2).pptxGomathi454280
The document discusses routing protocols and design challenges in wireless sensor networks. It describes how routing protocols select suitable paths for data to travel from source to destination, taking into account the type of network, channel characteristics, and performance metrics. It then lists several routing challenges in WSNs, including difficulties allocating identifiers, redundant data traffic, and limited energy, bandwidth, and storage of sensor nodes. Finally, it discusses key design challenges for WSN routing protocols, such as energy efficiency, complexity, scalability, delay, robustness, data transmission models, and locating sensor nodes.
Ad hoc & WSN Routing protocols (Geetha) (2).pptxGeetha336913
The document discusses routing protocols and design challenges in wireless sensor networks. It describes how routing protocols select suitable paths for data to travel from source to destination, taking into account the type of network, channel characteristics, and performance metrics. It then lists several routing challenges in WSNs, including difficulties allocating identifiers, redundant data traffic, and limited energy, bandwidth, and storage of sensor nodes. Finally, it discusses key design challenges for WSN routing protocols like energy efficiency, complexity, scalability, delay, robustness, data transmission models, and locating sensor nodes.
Wireless sensor networks use large numbers of small, low-cost sensors that communicate wirelessly to monitor conditions like temperature, sound, pollution levels, pressure, etc. Sensors collect data and pass it to a base station, which can be accessed through the internet. Wireless sensor networks can be used for applications like environmental monitoring, smart grids, healthcare, agriculture, and more. They face challenges related to power efficiency, security, scalability and operating in different environments.
A Review of Routing Protocols for Wireless Sensor NetworkIJMER
This document summarizes and reviews various routing protocols for wireless sensor networks. It begins by describing the characteristics and design objectives of wireless sensor networks. It then discusses the design constraints for routing in these networks, including autonomy, energy efficiency, scalability, resilience, and heterogeneity. The document classifies routing protocols into three categories: data-centric/negotiation-based, hierarchical/cluster-based, and location-based. Examples like SPIN, directed diffusion, LEACH, and PEGASIS are described for each category. Location-based protocols such as GAF that use node positions are also mentioned.
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Routing protocols for wireless sensor networks face several unique challenges compared to other wireless networks. This document discusses routing challenges in wireless sensor networks and provides an overview of different routing protocol approaches, including flat routing, hierarchical routing, location-based routing, and QoS-based routing. It specifically describes two flat routing protocols: directed diffusion, which uses data negotiation and aggregation to reduce energy costs, and SPIN, which employs data description messages to avoid redundant transmissions through negotiation between sensor nodes.
The document discusses software configuration management (SCM), including its definition, need, elements, roles and access levels, and version numbering. SCM involves managing project items like software, code, and artifacts in a structured way, securing them for privileged users only, and controlling modifications. It establishes configuration identification, control over elements like libraries and access, and change management.
This document discusses Wi-Fi security standards. It describes the original WEP security protocol and its weaknesses. It then summarizes the WPA and WPA2 security protocols, which were developed to improve upon WEP. WPA uses TKIP and RC4 encryption with 128-bit keys, while WPA2 uses AES encryption with 128-bit keys and stronger authentication methods like 802.1x to provide stronger security for wireless networks. Both WPA and WPA2 improved security by implementing dynamic session keys and better encryption standards compared to the flawed WEP protocol.
Touch ID is a fingerprint recognition feature introduced in the iPhone 5S that allows users to unlock their phone and make purchases with a fingerprint instead of a passcode. It is built into the home button using a fingerprint sensor. Fingerprint data is stored securely on the phone's processor and not on Apple servers. The document provides details on the history and acquisition of the technology by Apple, the hardware and sensor design, and how the security and privacy of fingerprints is maintained.
Literature Reivew of Student Center DesignPriyankaKarn3
It was back in 2020, during the COVID-19 lockdown Period when we were introduced to an Online learning system and had to carry out our Design studio work. The students of the Institute of Engineering, Purwanchal Campus, Dharan did the literature study and research. The team was of Prakash Roka Magar, Priyanka Karn (me), Riwaz Upreti, Sandip Seth, and Ujjwal Dev from the Department of Architecture. It was just a scratch draft made out of the initial phase of study just after the topic was introduced. It was one of the best teams I had worked with, shared lots of memories, and learned a lot.
A brand new catalog for the 2024 edition of IWISS. We have enriched our product range and have more innovations in electrician tools, plumbing tools, wire rope tools and banding tools. Let's explore together!
FD FAN.pdf forced draft fan for boiler operation and run its very important f...MDHabiburRhaman1
FD fan or forced draft fan, draws air from the atmosphere and forces it into the furnace through a preheater. These fans are located at the inlet of the boiler to push high pressure fresh air into combustion chamber, where it mixes with the fuel to produce positive pressure. and A forced draft fan (FD fan) is a fan that is used to push air into a boiler or other combustion chamber. It is located at the inlet of the boiler and creates a positive pressure in the combustion chamber, which helps to ensure that the fuel burns properly.
The working principle of a forced draft fan is based on the Bernoulli principle, which states that the pressure of a fluid decreases as its velocity increases. The fan blades rotate and impart momentum to the air, which causes the air to accelerate. This acceleration of the air creates a lower pressure at the outlet of the fan, which draws air in from the inlet.
The amount of air that is pushed into the boiler by the FD fan is determined by the fan’s capacity and the pressure differential between the inlet and outlet of the fan. The fan’s capacity is the amount of air that it can move per unit of time, and the pressure differential is the difference in pressure between the inlet and outlet of the fan.
The FD fan is an essential component of any boiler system. It helps to ensure that the fuel burns properly and that the boiler operates efficiently.
Here are some of the benefits of using a forced draft fan:Improved combustion efficiency: The FD fan helps to ensure that the fuel burns completely, which results in improved combustion efficiency.
Reduced emissions: The FD fan helps to reduce emissions by ensuring that the fuel burns completely.
Increased boiler capacity: The FD fan can increase the capacity of the boiler by providing more air for combustion.
Improved safety: The FD fan helps to improve safety by preventing the buildup of flammable gases in the boiler.
Forced Draft Fan ( Full form of FD Fan) is a type of fan supplying pressurized air to a system. In the case of a Steam Boiler Assembly, this FD fan is of great importance. The Forced Draft Fan (FD Fan) plays a crucial role in supplying the necessary combustion air to the steam boiler assembly, ensuring efficient and optimal combustion processes. Its pressurized airflow promotes the complete and controlled burning of fuel, enhancing the overall performance of the system.What is the FD fan in a boiler?
In a boiler system, the FD fan, or Forced Draft Fan, plays a crucial role in ensuring efficient combustion and proper air circulation within the boiler. Its primary function is to supply the combustion air needed for the combustion process.
The FD fan works by drawing in ambient air and then forcing it into the combustion chamber, creating the necessary air-fuel mixture for the combustion process. This controlled air supply ensures that the fuel burns efficiently, leading to optimal heat transfer and energy production.
In summary, the FD fan i
Response & Safe AI at Summer School of AI at IIITHIIIT Hyderabad
Talk covering Guardrails , Jailbreak, What is an alignment problem? RLHF, EU AI Act, Machine & Graph unlearning, Bias, Inconsistency, Probing, Interpretability, Bias
Social media management system project report.pdfKamal Acharya
The project "Social Media Platform in Object-Oriented Modeling" aims to design
and model a robust and scalable social media platform using object-oriented
modeling principles. In the age of digital communication, social media platforms
have become indispensable for connecting people, sharing content, and fostering
online communities. However, their complex nature requires meticulous planning
and organization.This project addresses the challenge of creating a feature-rich and
user-friendly social media platform by applying key object-oriented modeling
concepts. It entails the identification and definition of essential objects such as
"User," "Post," "Comment," and "Notification," each encapsulating specific
attributes and behaviors. Relationships between these objects, such as friendships,
content interactions, and notifications, are meticulously established.The project
emphasizes encapsulation to maintain data integrity, inheritance for shared behaviors
among objects, and polymorphism for flexible content handling. Use case diagrams
depict user interactions, while sequence diagrams showcase the flow of interactions
during critical scenarios. Class diagrams provide an overarching view of the system's
architecture, including classes, attributes, and methods .By undertaking this project,
we aim to create a modular, maintainable, and user-centric social media platform that
adheres to best practices in object-oriented modeling. Such a platform will offer users
a seamless and secure online social experience while facilitating future enhancements
and adaptability to changing user needs.
2. Overview
• Routing in WSNs is challenging due to distinguish from
other wireless networks like mobile ad hoc networks or
cellular networks.
– First, it is not possible to build a global addressing scheme for
a large number of sensor nodes. Thus, traditional IP-based
protocols may not be applied to WSNs. In WSNs, sometimes
getting the data is more important than knowing the IDs of
which nodes sent the data.
– Second, in contrast to typical communication networks,
almost all applications of sensor networks require the flow of
sensed data from multiple sources to a particular BS.
2
3. Overview (cont.)
– Third, sensor nodes are tightly constrained in terms of
energy, processing, and storage capacities. Thus, they
require carefully resource management.
– Fourth, in most application scenarios, nodes in WSNs are
generally stationary after deployment except for, may be, a
few mobile nodes.
– Fifth, sensor networks are application specific, i.e., design
requirements of a sensor network change with application.
– Sixth, position awareness of sensor nodes is important
since data collection is normally based on the location.
– Finally, data collected by many sensors in WSNs is typically
based on common phenomena, hence there is a high
probability that this data has some redundancy.
3
4. Overview (cont.)
• The task of finding and maintaining routes in WSNs is
nontrivial since energy restrictions and sudden
changes in node status (e.g., failure) cause frequent
and unpredictable topological changes.
• To minimize energy consumption, routing techniques
proposed for WSNs employ some well-known routing
strategies, e.g., data aggregation and in-network
processing, clustering, different node role
assignment, and data-centric methods were
employed.
4
5. Outline
o Routing Challenges and Design Issues in WSNs
o Flat Routing
o Hierarchical Routing
o Location Based Routing
o QoS Based Routing
5
7. Overview
• The design of routing protocols in WSNs is influenced by many
challenging factors. These factors must be overcome before
efficient communication can be achieved in WSNs.
– Node deployment
– Energy considerations
– Data delivery model
– Node/link heterogeneity
– Fault tolerance
– Scalability
– Network dynamics
– Transmission media
– Connectivity
– Coverage
– Data aggregation/convergecast
– Quality of service
7
8. Node Deployment
• Node deployment in WSNs is application dependent
and affects the performance of the routing protocol.
• The deployment can be either deterministic or
randomized.
• In deterministic deployment, the sensors are
manually placed and data is routed through pre-
determined paths.
• In random node deployment, the sensor nodes are
scattered randomly creating an infrastructure in an
ad hoc manner.
8
9. Energy Considerations
• Sensor nodes can use up their limited supply of
energy performing computations and transmitting
information in a wireless environment. Energy
conserving forms of communication and
computation are essential.
• In a multi-hop WSN, each node plays a dual role as
data sender and data router. The malfunctioning of
some sensor nodes due to power failure can cause
significant topological changes and might require
rerouting of packets and reorganization of the
network.
9
10. Data Delivery Model
• Time-driven (continuous)
– Suitable for applications that require periodic data
monitoring
• Event-driven
– React immediately to sudden and drastic changes
• Query-driven
– Respond to a query generated by the BS or another node
in the network
• Hybrid
• The routing protocol is highly influenced by the data
reporting method
10
11. Node/Link Heterogeneity
• Depending on the application, a sensor node can
have a different role or capability.
• The existence of a heterogeneous set of sensors
raises many technical issues related to data routing.
• Even data reading and reporting can be generated
from these sensors at different rates, subject to
diverse QoS constraints, and can follow multiple data
reporting models.
11
12. Fault Tolerance
• Some sensor nodes may fail or be blocked due to
lack of power, physical damage, or environmental
interferences
• It may require actively adjusting transmission powers
and signaling rates on the existing links to reduce
energy consumption, or rerouting packets through
regions of the network where more energy is
available
12
13. Scalability
• The number of sensor nodes deployed in the sensing
area may be on the order of hundreds or thousands,
or more.
• Any routing scheme must be able to work with this
huge number of sensor nodes.
• In addition, sensor network routing protocols should
be scalable enough to respond to events in the
environment.
13
14. Network Dynamics
• Routing messages from or to moving nodes is more
challenging since route and topology stability
become important issues
• Moreover, the phenomenon can be mobile (e.g., a
target detection/ tracking application).
14
15. Transmission Media
• In general, the required bandwidth of sensor data
will be low, on the order of 1-100 kb/s. Related to the
transmission media is the design of MAC.
– TDMA (time-division multiple access)
– CSMA (carrier sense multiple access)
15
16. Connectivity
• High node density in sensor networks precludes
them from being completely isolated from each other.
• However, may not prevent the network topology
from being variable and the network size from
shrinking due to sensor node failures.
• In addition, connectivity depends on the possibly
random distribution of nodes.
16
17. Coverage
• In WSNs, each sensor node obtains a certain view of
the environment.
• A given sensor’s view of the environment is limited in
both range and accuracy.
• It can only cover a limited physical area of the
environment.
17
18. Data Aggregation/Convergecast
• Since sensor nodes may generate significant
redundant data, similar packets from multiple nodes
can be aggregated to reduce the number of
transmissions.
• Data aggregation is the combination of data from
different sources according to a certain aggregation
function.
• Convergecasting is collecting information “upwards”
from the spanning tree after a broadcast.
18
19. Quality of Service
• In many applications, conservation of energy, which
is directly related to network lifetime.
• As energy is depleted, the network may be required
to reduce the quality of results in order to reduce
energy dissipation in the nodes and hence lengthen
the total network lifetime.
19
20. Routing Protocols in WSNs: A taxonomy
20
Network Structure Protocol Operation
Flat routing
• SPIN
• Directed Diffusion (DD)
Hierarchical routing
• LEACH
• PEGASIS
• TTDD
Location based routing
• GEAR
• GPSR
Negotiation based routing
• SPIN
Multi-path network routing
• DD
Query based routing
• DD, Data centric routing
QoS based routing
• TBP, SPEED
Coherent based routing
• DD
Aggregation
• Data Mules, CTCCAP
Routing protocols in WSNs
22. Overview
• In flat network, each node typically plays the same role and
sensor nodes collaborate together to perform the sensing
task.
• Due to the large number of such nodes, it is not feasible to
assign a global identifier to each node. This consideration
has led to data centric routing, where the BS sends queries
to certain regions and waits for data from the sensors
located in the selected regions. Since data is being
requested through queries, attribute-based naming is
necessary to specify the properties of data.
• Prior works on data centric routing, e.g., SPIN and Directed
Diffusion, were shown to save energy through data
negotiation and elimination of redundant.
22
24. SPIN -Motivation
• Sensor Protocols for Information via Negotiation,
SPIN
– A Negotiation-Based Protocols for Disseminating
Information in Wireless Sensor Networks.
• Dissemination is the process of distributing individual
sensor observations to the whole network, treating
all sensors as sink nodes
– Replicate complete view of the environment
– Enhance fault tolerance
– Broadcast critical piece of information
24
25. SPIN (cont.)- Motivation
• Flooding is the classic approach for dissemination
• Source node sends data to all neighbors
• Receiving node stores and sends data to all its
neighbors
• Disseminate data quickly
• Deficiencies
– Implosion
– Overlap
– Resource blindness
25
27. SPIN (cont.)- Overlap
27
q
r
s
(q, r) (s, r)
Node
The direction
of data sending
The connect
between nodes
The searching
range of the
node
A B
C
28. SPIN (cont.)- Resource blindness
• In flooding, nodes do not modify their activities
based on the amount of energy available to them.
• A network of embedded sensors can be resource-
aware and adapt its communication and
computation to the state of its energy resource.
28
29. SPIN (cont.)
• Negotiation
– Before transmitting data, nodes negotiate with each other
to overcome implosion and overlap
– Only useful information will be transferred
– Observed data must be described by meta-data
• Resource adaptation
– Each sensor node has resource manager
– Applications probe manager before transmitting or
processing data
– Sensors may reduce certain activities when energy is low
29
30. SPIN (cont.)- Meta-Data
• Completely describe the data
– Must be smaller than the actual data for SPIN to be
beneficial
– If you need to distinguish pieces of data, their meta-data
should differ
• Meta-Data is application specific
– Sensors may use their geographic location or unique node
ID
– Camera sensor may use coordinate and orientation
30
31. SPIN (cont.)- SPIN family
• Protocols of the SPIN family
– SPIN-PP
• It is designed for a point to point communication, i.e., hop-
by-hop routing
– SPIN-EC
• It works similar to SPIN-PP, but, with an energy heuristic
added to it
– SPIN-BC
• It is designed for broadcast channels
– SPIN-RL
• When a channel is lossy, a protocol called SPIN-RL is used
where adjustments are added to the SPIN-PP protocol to
account for the lossy channel.
31
32. SPIN (cont.)- Three-stage handshake
protocol
• SPIN-PP: A three-stage handshake protocol for point-
to-point media
– ADV – data advertisement
• Node that has data to share can advertise this by
transmitting an ADV with meta-data attached
– REQ – request for data
• Node sends a request when it wishes to receive some
actual data
– DATA – data message
• Contain actual sensor data with a meta-data header
• Usually much bigger than ADV or REQ messages
32
36. SPIN (cont.)- SPIN-EC (Energy-Conserve)
• Add simple energy-conservation heuristic to
SPIN-PP
– SPIN-EC: SPIN-PP with a low-energy threshold
• Incorporate low-energy-threshold
• Works as SPIN-PP when energy level is high
• Reduce participation of nodes when approaching
low-energy-threshold
– When node receives data, it only initiates protocol if it can
participate in all three stages with all neighbor nodes
– When node receives advertisement, it does not request the
data
• Node still exhausts energy below threshold by
receiving ADV or REQ messages
36
37. SPIN (cont.)- Conclusion
• SPIN protocols hold the promise of achieving high
performance at a low cost in terms of complexity,
energy, computation, and communication
• Pros
– Each node only needs to know its one-hop neighbors
– Significantly reduce energy consumption compared to flooding
• Cons
– Data advertisement cannot guarantee the delivery of data
• If the node interested in the data are far from the source,
data will not be delivered
• Not good for applications requiring reliable data delivery, e.g.,
intrusion detection
37
39. Overview
• Data-centric communication
– Data is named by attribute-value
pairs
– Different form IP-style
communication
• End-to-end delivery service
– e.g.
• How many pedestrians do you
observe in the geographical
region X?
39
Event
Sources
Sink Node
Directed
Diffusion
A sensor field
40. Overview (cont.)
• Data-centric communication (cont.)
– Human operator’s query (task) is diffused
– Sensors begin collecting information about query
– Information returns along the reverse path
– Intermediate nodes aggregate the data
• Combing reports from sensors
• Directed Diffusion is an important milestone in the
data centric routing research of sensor networks
40
41. Directed Diffusion
• Typical IP based networks
– Requires unique host ID addressing
– Application is end-to-end
• Directed diffusion – use publish/subscribe
– Inquirer expresses an interest, I, using attribute values
– Sensor sources that can service I, reply with data
41
42. Directed Diffusion (cont.)
• Directed diffusion consists of
– Interest - Query which specifies what a user wants
– Data - Collected information
– Gradient
• Direction and data-rate
• Events start flowing towards the originators of interests
– Reinforcement
• After the sink starts receiving events, it reinforces at
least one neighbor to draw down higher quality events
42
43. Directed Diffusion: Pros & Cons
• Different from SPIN in terms of on-demand
data querying mechanism
– Sink floods interests only if necessary (lots of energy savings)
– In SPIN, sensors advertise the availability of data
• Pros
– Data centric: All communications are neighbor to neighbor
with no need for a node addressing mechanism
– Each node can do aggregation & caching
• Cons
– On-demand, query-driven: Inappropriate for applications
requiring continuous data delivery, e.g., environmental
monitoring
– Attribute-based naming scheme is application dependent
• For each application it should be defined a priori
• Extra processing overhead at sensor nodes
43
44. Conclusions
• Directed diffusion, a paradigm proposed for event
monitoring sensor networks
• Directed Diffusion has some novel features -
data-centric dissemination, reinforcement-based
adaptation to the empirically best path, and in-
network data aggregation and caching.
• Notion of gradient (exploratory and reinforced)
• Energy efficiency achievable
• Diffusion mechanism resilient to fault tolerance
– Conservative negative reinforcements proves useful
44
46. Overview
• In a hierarchical architecture, higher energy nodes can be
used to process and send the information while low energy
nodes can be used to perform the sensing of the target.
• Hierarchical routing is mainly two-layer routing where one
layer is used to select cluster heads and the other layer is
used for routing.
• Hierarchical routing (or cluster-based routing), e.g., LEACH,
PEGASIS, TTDD, is an efficient way to lower energy
consumption within a cluster and by performing data
aggregation and fusion in order to decrease the number of
transmitted messages to the base stations.
46
48. LEACH
• LEACH (Low-Energy Adaptive Clustering Hierarchy), a
clustering-based protocol that minimizes energy
dissipation in sensor networks.
• LEACH outperforms classical clustering algorithms by
using adaptive clusters and rotating cluster-heads,
allowing the energy requirements of the system to be
distributed among all the sensors.
• LEACH is able to perform local computation in each
cluster to reduce the amount of data that must be
transmitted to the base station.
• LEACH uses a CDMA/TDMA MAC to reduce inter-
cluster and intra-cluster collisions.
48
49. LEACH (cont.)
• Sensors elect themselves to be local cluster-heads at
any given time with a certain probability.
• Each sensor node joins a cluster-head that requires
the minimum communication energy.
• Once all the nodes are organized into clusters, each
cluster-head creates a transmission schedule for the
nodes in its cluster.
• In order to balance the energy consumption, the
cluster-head nodes are not fixed; rather, this position
is self-elected at different time intervals.
49
51. LEACH: Adaptive Clustering
• Periodic independent self-election
– Probabilistic
• CSMA MAC used to advertise
• Nodes select advertisement with strongest signal strength
• Dynamic TDMA cycles
51
All nodes marked with a given symbol belong to the same cluster, and
the cluster head nodes are marked with a ●.
52. Algorithm
• Periodic process
• Two phases per round:
– Setup phase
• Advertisement: Execute election algorithm
• Members join to cluster
• Cluster-head broadcasts schedule
– Steady-State phase
• Data transmission to cluster-head using TDMA
• Cluster-head transfers data to BS (Base Station)
52
53. 53
Algorithm (cont.)
53
Advertisement phase Cluster setup phase Broadcast schedule
Time slot
1
Time slot
2
Time slot
3
Setup phase Steady-state phase
Self-election of cluster
heads
Cluster heads compete
with CSMA
Members
compete with
CSMA
Cluster head Broadcast
CDMA code to members
Fixed-length cycle
54. Algorithm Summary
• Set-up phase
– Node n choosing a random number m between 0 and 1
– If m < T(n) for node n, the node becomes a cluster-head where
– where P = the desired percentage of cluster heads (e.g., P= 0.05),
r=the current round, and G is the set of nodes that have not
been cluster-heads in the last 1/P rounds. Using this threshold,
each node will be a cluster-head at some point within 1/P
rounds. During round 0 (r=0), each node has a probability P of
becoming a cluster-head.
54
1 [ * mod(1/ )]( )
0 ,
P
if n G
P r PT n
otherwise
55. Algorithm Summary (cont.)
• Set-up phase
– Cluster heads assign a TDMA schedule for their members where
each node is assigned a time slot when it can transmit.
– Each cluster communications using different CDMA codes to
reduce interference from nodes belonging to other clusters.
• TDMA intra-cluster
• CDMA inter-cluster
– Spreading codes determined randomly
– Broadcast during advertisement phase
55
56. Algorithm Summary (cont.)
• Steady-state phase
– All source nodes send their data to their cluster heads
– Cluster heads perform data aggregation/fusion through
local transmission
– Cluster heads send aggregated data back to the BS using a
single direct transmission
56
57. An Example of a LEACH Network
• While neither of these diagrams is the
optimum scenario, the second is better
because the cluster-heads are spaced out and
the network is more properly sectioned
57
Node
Cluster-Head Node
Node that has been cluster-head in the last 1/P rounds
Cluster Border
X
Bad case scenarioGood case scenario
58. Conclusions
• Advantages
– Increases the lifetime of the network
– Even drain of energy
– Distributed, no global knowledge required
– Energy saving due to aggregation by CHs
• Disadvantages
– LEACH assumes all nodes can transmit with enough power
to reach BS if necessary (e.g., elected as CHs)
– Each node should support both TDMA & CDMA
– Need to do time synchronization
– Nodes use single-hop communication
58
60. Overview
• Sensor nodes are addressed by means of their locations.
– The distance between neighboring nodes can be estimated on
the basis of incoming signal strengths.
– Relative coordinates of neighboring nodes can be obtained by
exchanging such information between neighbors.
• To save energy, some location based schemes demand that
nodes should go to sleep if there is no activity.
• More energy savings can be obtained by having as many
sleeping nodes in the network as possible.
• Hereby, two important location based routing protocols,
GEAR and GPSR, are introduced.
– Geographical and Energy Aware Routing (GEAR)
– Greedy Perimeter Stateless Routing (GPSR)
60
62. Geographical and Energy Aware Routing (GEAR)
• The protocol, called Geographic and Energy Aware
Routing (GEAR), uses energy aware and geographically-
informed neighbor selection heuristics to route a
packet towards the destination region.
• The key idea is to restrict the number of interests in
directed diffusion by only considering a certain region
rather than sending the interests to the whole network.
By doing this, GEAR can conserve more energy than
directed diffusion.
• The basic concept comprises of two main parts
– Route packets towards a target region through geographical and
energy aware neighbor selection
– Disseminate the packet within the region
62
63. Energy Aware Neighbor Computation
• Each node N maintains state h(N, R) which is called
learned cost to region R, where R is the target region
• Each node infrequently updates neighbor of its cost
• When a node wants to send a packet, it checks the
learned cost to that region of all its neighbors
• If a node does not have the learned cost of a neighbor
to a region, the estimated cost is computed as follows:
c(Ni, R) = αd(Ni, R) + (1-α)e(Ni)
where
α = tunable weight, from 0 to 1.
d(Ni, R) = normalized the largest distance among neighbors of N
e(Ni) = normalized the largest consumed energy among neighbors of N
63
64. Energy Aware Neighbor Computation (cont.)
• When a node wants to forward a packet to a
destination, it checks to see if it has any neighbor
closer to destination than itself
• In case of multiple choices, it aims to minimize the
learned cost h(Nmin, R)
• It then sets its own cost to:
h(N, R) = h(Nmin, R) + c(N, Nmin)
c(N, Nmin) = the transmission cost from N and
Nmin
64
65. Conclusion
• GEAR strategy attempts to balance energy
consumption and thereby increase network lifetime
• GEAR performs better in terms of connectivity after
initial partition
65
67. Greedy Perimeter Stateless Routing (GPSR)
• Greedy Perimeter Stateless Routing (GPSR) proposes
the aggressive use of geography to achieve scalability
• GEAR was compared to a similar non-energy-aware
routing protocol GPSR, which is one of the earlier
works in geographic routing that uses planar graphs to
solve the problem of holes
• In case of GPSR, the packets follow the perimeter of
the planar graph to find their routes
• Although the GPSR approach reduces the number of
states a node should keep, it has been designed for
general mobile ad hoc networks and requires a location
service to map locations and node identifiers.
67
68. Algorithm & Example
• The algorithm consists of two methods:
greedy forwarding + perimeter forwarding
• Greedy forwarding, which is used wherever possible,
and perimeter forwarding, which is used in the
regions greedy forwarding cannot be done.
68
69. Greedy Forwarding (cont.)
• Under GPSR, packets are marked by their originator
with their destinations’ locations
• As a result, a forwarding node can make a locally
optimal, greedy choice in choosing a packet’s next
hop
• Specifically, if a node knows its radio neighbors’
positions, the locally optimal choice of next hop is
the neighbor geographically closest to the packet’s
destination
• Forwarding in this scheme follows successively closer
geographic hops, until the destination is reached
69
71. Greedy Forwarding (cont.)
• A simple beaconing algorithm provides all nodes with
their neighbors’ positions: periodically, each node
transmits a beacon to broadcast MAC address,
containing its own identifier (e.g., IP address) and
position
• Position is encoded as two four-byte floating point
quantities, for x and y coordinate values
• Upon not receiving a beacon from a neighbor for
longer than timeout interval T, a GPSR router
assumes that the neighbor has failed or gone out-of-
range, and deletes the neighbor from its neighbor
table
71
72. Greedy Forwarding (cont.)
The Problem of Greedy Forwarding
72
x
w y
D
v z
|xD|<|wD|and|yD|
x will not choose to
forward to w or y
using greedy
forwarding
void
xx
73. Conclusion
• GPSR’s benefits all stem from geographic routing’s
use of only immediate-neighbor information in
forwarding decisions.
• GPSR keeps state proportional to the number of its
neighbors, while both traffic sources and
intermediate DSR routers cache state proportional to
the product of the number of routes learned and
route length in hops.
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75. Overview
• QoS is the performance level of service offered by a
network to the user.
• The goal of QoS is to achieve a more deterministic
network behavior so that the information carried by the
network can be better delivered and the resources can
be better utilized.
• In QoS-based routing protocols, the network has to
balance between energy consumption and data quality.
• In particular, the network has to satisfy certain QoS
metrics, e.g., delay, energy, bandwidth, etc. when
delivering data to the BS.
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76. Parameters of QoS Networks
• Different services require different QoS parameters
– Multimedia
• Bandwidth, delay jitter & delay
– Emergency services
• Network availability
– Group communications
• Battery life
• Generally the parameters that are important are:
– bandwidth
– delay jitter
– battery charge
– processing power
– buffer space
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77. Challenges in QoS Routing
• Dynamically varying network topology
• Imprecise state information
• Lack of central coordination
• Hidden node problem
• Limited resource
• Insecure medium
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