Title: A Survey on Routing Protocols for Wireless Sensor Networks
1A Survey on Routing Protocols for Wireless Sensor
Networks
- By Kemal Akkaya Mohamed Younis
- Presented by
- Aggelos Vlavianos
- Jorge Mena
- Department of Computer Science and Engineering
- 02/08/05
2Table of Contents
- Goals
- Introduction
- System Architecture Designing
- Protocols for Sensor Networks
- Summary
3Goals
- A survey of recent routing protocols for sensor
networks - Classification of these protocols
4Introduction
- Sensors are micro-electro-mechanical systems
(MEMS) - Low power devices
- Data processing capable
- Communication capabilities
5Introduction - Usage
- Gather data locally (Temperature, Humidity,
Motion Detection, etc.) - Send them to a command center (sink)
- Applications
- Surveillance
- Security
- Disaster Management
- Environmental Studies
6Introduction - Constraints
- Limitations
- Energy Constrains
- Bandwidth
- All layers must be energy aware
- Need for energy efficient and reliable network
routing - Maximize the lifetime of the network
7Introduction - Routing
- No global addressing
- Redundant data traffic
- Multiple-source single-destination network
- Careful resource management
- Transmission power
- On-board energy
- Processing capacity
- Storage
8System Architecture Designing
- Network Dynamics
- Mobile or Stationary nodes
- Static Events (Temperature)
- Dynamic Events ( Target Detection)
- Node Deployment
- Deterministic Placed manually
- Self-organizing Scattered randomly
9System Architecture Designing
- Energy Considerations
- Direct vs Multi-hop communication
- Direct Preferred Sensors close to sink
- Multi-hop unavoidable in randomly scattered
networks - Data Delivery Models
- Continuous
- Event-driven
- Query-driven
- Hybrid
10System Architecture Designing
- Node Capabilities
- Homogenous
- Heterogeneous
- Nodes dedicated to a particular task (relaying,
sensing, aggregation) - Data Aggregation/Fusion
- Aggregation Combination of data by eliminating
redundancy - Data Fusion is Aggregation through signal
processing techniques - Aggregation achieves energy savings
11Introduction - Taxonomy
- Classification of Routing Protocols
- Data Centric
- Hierarchical
- Location-based
- Network Flow QoS Aware
12Data-centric Protocols
- Sink sends queries to certain regions and waits
data from sensors located in that region - Attribute-based naming is necessary to specify
properties of data
13Data-centric Protocols
- Flooding
- Gossiping
- Sensor Protocols for Information via Negotiation
(SPIN) - Directed Diffusion
- Energy-aware Routing
- Rumor Routing
- Gradient-Based Routing (GBR)
- Constrained Anisotropic Diffusion Routing (CADR)
- COUGAR
- ACtive QUery forwarding In sensoR nEtworks
(ACQUIRE)
14Data-centric Protocols
- Flooding
- Sensor broadcasts every packet it receives
- Relay of packet till the destination or maximum
number of hops - No topology maintenance or routing
- Gossiping
- Enhanced version of flooding
- Sends received packet to a randomly selected
neighbor
15Data-centric Protocols Flooding, Gossiping
Problems
- Problems of Implosion, Overlap, Resource
Blindness
16Data-centric Protocols
- Sensor Protocols for Information via Negotiation
(SPIN)
17Data-centric Protocols - SPIN
- Topological changes are localized - Each node
needs to know only its neighbors - SPIN halves the redundant data in comparison to
flooding - Cannot guarantee data delivery
- SPIN NOT good for applications that need reliable
data delivery
18Data-centric Protocols
- Directed Diffusion
- Uses a naming scheme for the data to save energy
- Attribute-value pairs for data and queries
on-demand (Interests) - Interests are broadcasted by the sink (query) to
its neighbors (caching), which can do in-network
aggregation - Gradients reply links to an interest (path
establishment)
19Data-centric Protocols Direct Diffusion
- Energy saving and delay done with caching
- No need for global addressing (neighbor-to-neighbo
r mechanism) - Cannot be used for continuous data delivery or
event-driven applications
20Data-centric Protocols
- Energy-aware Routing
- Occasional use of a set of sub-optimal paths
- Multiple paths used with certain probability
- Increase of the total lifetime of the network
- Hinders the ability for recovering from node
failure - Requires address mechanism ?Complicate setup
21Data-centric Protocols
- Rumor Routing
- Variation of Directed Diffusion
- Flood the events instead of the queries
- Creation of an event ? generation of a long live
packet travel through the network (agent) - Nodes save the event in a local table
- When a node receives query ? checks its table and
returns source destination path
22Data-centric Protocols Rumor Routing
- Advantages
- Can handle node failure
- Significant energy savings
- Disadvantages
- Works well only with small number of events
- Overhead through adjusting parameters, like the
time to live of the agent
23Data-centric Protocols
- Gradient-Based Routing (GBR)
- Slightly changed version of Directed Diffusion
- Keep the number of hops to the sink when an
interest is created (height of the node) - Nodes height neighbors height gradient of
the link - Node forward packet to the link with largest
gradient
24Data-centric Protocols -GBR
- Traffic Spreading and Data Aggregation ? Balance
uniformly the network traffic - Stochastic scheme
- Energy-based scheme
- Stream-based scheme
- Outperforms Directed Diffusion in terms of total
communication energy
25Data-centric Protocols
- Constrained Anisotropic Diffusion Routing (CADR)
- General form of Directed Diffusion
- Query Sensors
- Route data in the network
- Activates sensors close to the event and
dynamically adjusts routes - Routing based on a local information/cost
gradient - More energy efficient than Directed Diffusion
26Data-centric Protocols
- COUGAR
- Views the network as a huge distributed database
- Declarative queries to abstract query processing
from network layer functions - Introduces a new query layer
- Leader node performs data aggregation and
transmits to the sink
27Data-centric Protocols - COUGAR
- Disadvantages
- Additional query layer brings overhead in terms
of energy consumption and storage - In network data computation requires
synchronization (i.e. wait for all data before
sending data) - Dynamically maintenance of leader nodes to
prevent failure
28Data-centric Protocols
- ACtive QUery forwarding In sensoR nEtworks
(ACQUIRE) - Views network as a distributed database
- Node receiving a query from the sink tries to
respond partially and then forwards packet to a
neighbor - Use of pre-cached information
- After the query is answered, result is returned
to the sink by using the reverse path or the
shortest path - If cache information is not up to date ? node
gathers information from neighbors within look
ahead of d hops
29Data-centric Protocols ACQUIRE
- Motivation Deal with one shot complex queries
- Efficient routing by adjusting parameter d
- If d equals network size ? behaves similar to
flooding - If d too small the query has to travel more hops
30Hierarchical Protocols
- Maintain energy consumption of sensor nodes
- By multi-hop communication within a particular
cluster - By data aggregation and fusion ? decrease the
number of the total transmitted packets -
31Hierarchical Protocols
- LEACH Low-Energy Adaptive Clustering Hierarchy
- Power-Efficient GAthering in Sensor Information
Systems (PEGASIS) - Hierarchical PEGASIS
- Threshold sensitive Energy Efficient sensor
Network protocol (TEEN) - Adaptive Threshold TEEN (APTEEN)
- Energy-aware routing for cluster-based sensor
networks - Self-organizing protocol
32Hierarchical Protocols
- LEACH Low-Energy Adaptive Clustering Hierarchy
- One of the first hierarchical routing protocols
- Forms clusters of the sensor nodes based on
received signal strength - Local cluster heads route the information of the
cluster to the sink - Cluster heads change randomly over time ? balance
energy dissipation - Data processing aggregation done by cluster
head
33Hierarchical Protocols - LEACH
- Advantages
- Completely distributed
- No global knowledge of the network
- Increases the lifetime of the network
- Disadvantages
- Uses single-hop routing within cluster ?not
applicable to networks in large regions - Dynamic clustering brings extra overhead
(advertisements, etc)
34Hierarchical Protocols
- Power-Efficient GAthering in Sensor Information
Systems (PEGASIS) - Improvement of LEACH
- Forms chains from sensors rather than clusters
- Data aggregation in the chain ? one node sends
the data to the base station - Outperforms LEACH
- Excessive delay for distant nodes in the chain
35Hierarchical Protocols
- Hierarchical PEGASIS
- Extension of PEGASIS
- Decrease the delay for the packets during
transmission to the base station - Solution to the delay data gathering problem
- Simultaneous transmissions of data messages
- Avoid collisions and possible signal interference
- Signal Coding (e.g. CDMA)
- Spatially separated nodes can transmit at the
same time
36Hierarchical Protocols
- Threshold sensitive Energy Efficient sensor
Network protocol (TEEN) - Good for time-critical applications
- Hierarchical along with a data-centric approach
- Hierarchical grouping Close nodes form clusters
and this process goes on the second level until
sink is reached - Cluster headers broadcast
- Hard Threshold
- Soft Threshold
- Not good for applications that need periodic
reports
37Hierarchical Protocols
38Hierarchical Protocols
- Adaptive Threshold TEEN (APTEEN)
- Captures both periodic data collection and
reacting to time-critical events - APTEEN supports queries
- Historical -Analyze past data values
- One-Time Take a snapshot of the current network
view - Persistent monitor an event for a period of time
39Hierarchical Protocols TEEN APTEEN
- Advantages
- Outperform LEACH in terms of energy dissipation
and total lifetime of the network - Disadvantages
- Overhead and complexity of
- Forming multiple level clusters
- Implementing threshold-based functions
- Dealing with attribute-based naming of queries
-
40Hierarchical Protocols
- Energy-aware routing for cluster-based sensor
networks - Assumptions
- Sensors are grouped into clusters prior to
network operation - Cluster Heads (Gateways) less energy constrained
- Cluster Heads know the location of the sensors ?
Known Multi-Hop routing to collect data - Communication node (sink) communicates only with
gateways
41Hierarchical Protocols
- Stages of a Sensor inside a cluster
- Sensing only
- Relaying only
- Sensing-Relaying
- Inactive
42Hierarchical Protocols
- Least Cost path used between nodes and gateway
- Cost function
- Energy Consumption
- Delay Optimization
- Performance Metrics
- TDMA based MAC is used for nodes to send data to
the gateways - Protocol performs well for
- Energy-based metrics (e.g. network lifetime)
- Cotemporary metrics (e.g. throughput)
43Hierarchical Protocols
- Self-organizing protocol
- Architecture supports heterogeneous sensors
- Nodes act as routers ? backbone of communication
- Stationary
- Sensing nodes forward data to the routers
- Stationary
- Mobile
- Sensors are a part of the network if they are
reachable by a router
44Hierarchical Protocols
- The architecture requires addressing
- Sensor identified by the router is connected to
- Algorithm for Self-Organizing Creation of
routing table - Discovery phase
- Organization phase
- Maintenance phase
- Self-reorganization phase
- Utilizes router nodes to keep all sensors
connected by forming a dominating set
45Hierarchical Protocols
- Advantages
- Useful for applications which need communication
of a specific node (e.g. parking-lot networks) - Small cost of maintaining routing tables
- Keeping routing hierarchy strictly balanced
- Energy Savings Utilization of a limited subset
of nodes - Disadvantages
- Organization phase not on demand
- Many cuts in the network increase the probability
of applying reorganization phase
46Location-based Protocols
- Distance between two nodes is calculated using
location information - Energy consumption can be estimated
- Efficient energy utilization
- Protocols designed for Ad hoc networks with
mobility in mind - Applicable to Sensor Networks as well
- Only energy-aware protocols are considered
47Location-based Protocols
- MECN SMECN
- Minimum Energy Communication Network
- GAF
- Geographic Adaptive Fidelity
- GEAR
- Geographic and Energy Aware Routing
48MECN SMECN
- Utilizes low power GPS
- Best applicable to non-mobile sensor networks
- Identifies a relay region
- Find a sub-network
- to relay traffic
- Self-reconfiguring
- Dynamically adaptive
49SMECN
- Assumption broadcasting allowed
- Obstacles considered
- Smaller network (number of edges)
- Less hops per transmission
- More energy efficient than MECN
- Less maintenance cost of links
- More overhead introduced
50GAF
- Forms a virtual grid for covered area
- Nodes use GPS to associate itself to the grid
- Nodes are allowed
- to be turned off if are
- equivalent.
- Handle mobility
51GAF
- Three States
- Discovery
- Active
- Sleep
- Representative Node is always active
- No aggregation or fusion performed
- As good as a normal Ad hoc in terms of latency
and packet loss (saving energy)
52GEAR
- Uses heuristics to route packets
- Energy aware neighbor
- Geographic informed neighbor
- Same as Direct Diffusion but restricts interest
by region - Estimated Cost
- Residual energy and distance to destination
- Learned Cost
- Accounts for routing around holes
53Network Flow QoS-aware Protocols
- Network Flow Maximize traffic flow between two
nodes, respecting the capacities of the links - QoS-aware protocols consider end-to-end delay
requirements while setting up paths
54Network Flow QoS-aware Protocols
- Maximum Lifetime Energy Routing
- Maximum Lifetime Data Gathering
- Minimum Cost Forwarding
- Sequential Assignment Routing
- Energy Aware QoS Routing Protocol
- SPEED
55Maximum Lifetime Energy Routing
- Maximizes network lifetime by defining link cost
as a function of - Remaining energy
- Required transmission energy
- Tries to find traffic distribution (Network flow
problem) - The least cost path is one with the highest
residual energy among paths
56Maximum Lifetime Data Gathering
- Maximizes the Data-gathering schedule
- Maximum Lifetime Data Aggregation
- Data aggregation plus setting up maximum lifetime
of routes - Maximum Lifetime Data Routing
- When data aggregation is not possible
- Computational Expensive (scalability)
- Clustering MLDA
57Minimum Cost Forwarding
- Aims at finding the minimum cost path in a large
network, simple and scalable - Cost function captures delay, throughput, and
energy metrics from node to sink - Back-off based algorithm
- Finds optimal cost of all nodes to the sink by
using only one message per node - Does not require addressing or forwarding paths
58Sequential Assignment Routing
- Table-driven, multi-path protocol
- Creates trees rooted at immediate neighbors of
the sink (multiple paths) - QoS metrics, energy resource, priority level of
each packet - Failure recoverable (done locally)
- High overhead to maintain tables and states at
each sensor
59Energy Aware QoS Routing Protocol
- Finds least cost and energy efficient paths that
meet the end-to-end delay during connection - Energy reserve, transmission energy, error rate
- Class-based queuing model used to support
best-effort and real-time traffic
60Energy Aware QoS Routing Protocol
61SPEED
- Each node maintains info about its neighbors and
uses geographic forwarding to find the paths - Tries to ensure a certain speed for each packet
in the network - Congestion avoidance
62Summary
63Questions