Transcript
7/25/2019 Ruting Protocol for Wsn
1/57
ROUTINGPROTOCOLS FOR
WSN
1
UNIT V
Created by : Neha Birla
7/25/2019 Ruting Protocol for Wsn
2/57
2
Data Dissemination and Gathering
Dissemination = The act of spreading something,
spreading, distribution.
Gathering = Assemble or collect
7/25/2019 Ruting Protocol for Wsn
3/57
1. Data Dissemination
3
Process of Distribution of data.
Information flow from one sensor node to another.
The originator of data is known as Source Nodeand
Receiver of the data is calledSink nodeorGateway.
The Sink registers itsinterestto receive the data from
source. The Source reports the data information to the
Sink. The information thus reported is calledevent.
7/25/2019 Ruting Protocol for Wsn
4/57
Process of Data Dissemination
4
The node that is interested in some events, like temperature
or air humidity, broadcasts its interests to its neighbors
periodically. Interests are then propagated through the
whole sensor network.
Nodes that have requested data, send back data after
receiving the request.
Intermediate nodes in the sensor network also keep a cache
of received interests and data.
7/25/2019 Ruting Protocol for Wsn
5/57
Data Dissemination Methods
5
Flooding
Gossiping
SPIN
7/25/2019 Ruting Protocol for Wsn
6/57
1.1 Flooding
6
Each node which receives a packet (queries/data) broadcasts it if
the maximum hop-count of the packet is not reached and the node
itself is not the destination of the packet.
Advantage
No costly topology maintenance or route discovery
Disadvantages
Implosion
Overlapping
Resource Blindness
7/25/2019 Ruting Protocol for Wsn
7/57
Implosion : This is the situation When duplicate messages are
send to the same node. This occurs when a node receives copies
of the same messages from many of its neighbors
7
7/25/2019 Ruting Protocol for Wsn
8/57
8
Overlap : Overlap is another problem which occurs when using
flooding. If two nodes share the same observation region both nodes
will witness an event at the same time and transmit details of this
event.
Resource blindness : the flooding protocol does not consider the
available energy at the nodes and results in many redundant
transmissions. Hence, it reduces the network lifetime.
7/25/2019 Ruting Protocol for Wsn
9/57
1.2 Gossiping
Modified version of flooding
The nodes do not broadcast a packet, but
send it to a randomly selected neighbor.
Avoid the problem of implosion by making
one copy of each message at any node
It takes a long time for message to propagate
throughout the network.
The hop count can become quite large due to
the protocols random nature
9
7/25/2019 Ruting Protocol for Wsn
10/57
1.3 Sensor Protocols for Information via
Negotiation
10
SPIN use negotiation and resource adaptation to address the
disadvantage of flooding and Use meta-data instead of raw data.
Reduce overlap and implosion, and prolong network lifetime.
SPIN-1 has three types of messages: ADV, REQ, and DATA.
SPIN-2 using an energy threshold to reduce participation. A node
may join in the ADV-REQ-DATA handshake only if it has
sufficient resource above a threshold.
7/25/2019 Ruting Protocol for Wsn
11/57
11
7/25/2019 Ruting Protocol for Wsn
12/57
2. Data Gathering
12
The objective of the data gathering problem is to transmit the
sensed data from each sensor node to a BS.
The goal of algorithm which implement data gathering is
maximize the lifetime of network
Minimum energy should be consumed
The transmission occur with minimum delay
7/25/2019 Ruting Protocol for Wsn
13/57
Difference between Data Dissemination
and Gathering
13
Data Dissemination Data Gathering
1 Any node can request the
data along with base station.
All data is transmitted to the
base station
2 Data is always transmitted
on demand
Data can be transmitted
periodically
7/25/2019 Ruting Protocol for Wsn
14/57
Data Gathering Approaches
14
Direct Transmission
Power-Efficient Gathering for Sensor Information Systems
Binary Scheme
7/25/2019 Ruting Protocol for Wsn
15/57
2.1 Direct Transmission
15
All sensor nodes transmit their data directly to the BS.
It cost expensive when the sensor nodes are very far from the BS.
Nodes must take turns while transmitting to the BS to avoid
collision, so the media access delay is also large. Hence, this
scheme performs poorly with respect to the energy x delay metric.
7/25/2019 Ruting Protocol for Wsn
16/57
2.2 Power-Efficient Gathering for Sensor
Information Systems
16
PEGASIS based on the assumption that all sensor nodes know the
location of every other node.
Any node has the required transmission range to reach the BS in
one hop, when it is selected as a leader.
The goal of PEGASIS are as following
Minimize the distance over which each node transmit
Minimize the broadcasting overhead
Minimize the number of messages that need to besent to the BS
Distribute the energy consumption equally across all nodes
7/25/2019 Ruting Protocol for Wsn
17/57
17
To construct a chain of sensor nodes, starting from the node
farthest from the BS. At each step, the nearest neighbor which has
not been visited is added to the chain.
This algorithm uses greedy algorithm for chain construction.
Before first round of communication chain formation is done
During formation of chain care must be taken so that nodes
already in chain should not revisited
It is reconstructed when nodes die out.
At every node, data fusion or aggregation is carried out.
7/25/2019 Ruting Protocol for Wsn
18/57
A node which is designated as the leader finally transmits one
message to the BS.
Leadership is transferred in sequential order.
The delay involved in messages reaching the BS is O(N)
18
7/25/2019 Ruting Protocol for Wsn
19/57
Figure 5 : Data gathering with PEGASIS
19
7/25/2019 Ruting Protocol for Wsn
20/57
2.3 Binary Scheme
This is a chain-based scheme like PEGASIS, which classifies
nodes into different levels.
This scheme is possible when nodes communicate using CDMA,
so that transmissions of each level can take place simultaneously.
The delay is O(log2N)
20
7/25/2019 Ruting Protocol for Wsn
21/57
Advantages
Low delay of only O(log2N), where the N is the amountof
nodes.
Disadvantages
Non equal distribution of energy consumption, nodes that are
active on several levels consume more energy than nodes that
are only active at the first level. This might lead to the
situation where some of sensor nodes die earlier than others.
Transmission distances may become long in high levels,
which leads to a high power consumption
21
7/25/2019 Ruting Protocol for Wsn
22/57
22
Routing Challenges and Design
Issues in WSN
The design of routing protocols in WSNs is influenced bymany challenging factors. These factors must be overcome
before efficient communication can be achieved in WSNs.
Node deployment Energy considerations
Data delivery model
7/25/2019 Ruting Protocol for Wsn
23/57
23
Node/link heterogeneity Fault tolerance
Scalability
Network dynamics
Transmission media
Connectivity
Coverage
Data aggregation/converge cast
Quality of service
7/25/2019 Ruting Protocol for Wsn
24/57
Node Deployment
24
Node deployment in WSNs isapplication dependent and affects
the performance of the routing protocol.
The deployment can be eitherdeterministicorrandomized.
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.
7/25/2019 Ruting Protocol for Wsn
25/57
Energy Considerations
25
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 asdata 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.
7/25/2019 Ruting Protocol for Wsn
26/57
Data Delivery Model
26
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
7/25/2019 Ruting Protocol for Wsn
27/57
Node/Link Heterogeneity
27
Depending on the application, a sensor node can have a
different role or capability.
The existence of aheterogeneous 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.
7/25/2019 Ruting Protocol for Wsn
28/57
Fault Tolerance
28
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
7/25/2019 Ruting Protocol for Wsn
29/57
Scalability
29
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.
7/25/2019 Ruting Protocol for Wsn
30/57
Network Dynamics
30
Routing messages from or to moving nodes is more
challenging since route and topology stability become
important issuesMoreover, the phenomenon can be mobile (e.g., a
target detection/ tracking application).
7/25/2019 Ruting Protocol for Wsn
31/57
Transmission Media
31
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)
7/25/2019 Ruting Protocol for Wsn
32/57
Connectivity
32
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.
7/25/2019 Ruting Protocol for Wsn
33/57
Coverage
33
In WSNs, each sensor node obtains a certain view of theenvironment.
A given sensors view of the environment is limited in both
range and accuracy.
It can only cover a limited physical area of the environment.
7/25/2019 Ruting Protocol for Wsn
34/57
Data Aggregation/Convergecast
34
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.
Converge casting is collecting information upwardsfrom the
spanning tree after a broadcast.
7/25/2019 Ruting Protocol for Wsn
35/57
Quality of Service
35
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.
7/25/2019 Ruting Protocol for Wsn
36/57
Routing Protocols in WSNs: A taxonomy
36
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
7/25/2019 Ruting Protocol for Wsn
37/57
37
Routing Strategies inWSN
7/25/2019 Ruting Protocol for Wsn
38/57
Routing Strategies
38
Aim to make communication more efficient
Trade-off between routing overhead and datatransmission cost
Strategies incur differing levels of communicationand storage overhead
Hybrid approaches are possible
7/25/2019 Ruting Protocol for Wsn
39/57
Proactive and Reactive Routing
39
Proactive routing Routes created and maintained in advance
E.g : LEACH protocol
Does not scale to large networks
Reactive routing
Routes created and cached as required
E.g : TEEN protocol
Dynamic delays
7/25/2019 Ruting Protocol for Wsn
40/57
Geographic and Energy Aware Routing
40
Motivation: Reduce overhead of interest and low rate data flooding in directed
diffusion
Basic ideas: Leverage geographical information to restrict flooding, and
recursively disseminate data inside the target region.
Extend overall network lifetime using local techniques tobalanceenergy usage
Reuse routing information across multiple user queries.
7/25/2019 Ruting Protocol for Wsn
41/57
Geographic and Energy Aware Routing
Forward the packets towards thetarget region: Greedy mode: minimizing cost
function (f=mix function of distanceand energy)
Route around communicationholes with energy aware neighborestimation
Disseminate the packet within thetarget region:
Geographic Recursive Forwarding recursively re-send packets to sub-
regions of the original geographicregion
41
7/25/2019 Ruting Protocol for Wsn
42/57
Geographic and Energy Aware Routing
Each node has a learned cost(historical cost) and anestimated cost (present statecost) to decide the next
forwarding node Learned cost
Estimated cost
min min( , ) ( , ) ( , )h N R h N R C N N
( , ) ( , ) (1 ) ( )i i i
c N R d N R e N
42
7/25/2019 Ruting Protocol for Wsn
43/57
G P S R : G R E E D Y P E R I M E T E R S T A T E L E S S
R O U T I N G F O R W I R E L E S S N E T W O R K S
43
Geographic Routing
7/25/2019 Ruting Protocol for Wsn
44/57
Motivation
44
A sensor net consists of hundreds or thousands of nodes Scalability is the issue
Existing ad hoc net protocols, e.g., DSR, AODV, ZRP, require nodesto cache e2e route information
Dynamic topology changes Mobility
Reduce caching overhead
Hierarchical routing is usually based on well defined, rarely changingadministrative boundaries
Geographic routing
Use location for routing
7/25/2019 Ruting Protocol for Wsn
45/57
Scalability metrics
45
Routing protocol msg cost How many control packets sent?
Per node state
How much storage per node is required?
E2E packet delivery success rate
7/25/2019 Ruting Protocol for Wsn
46/57
Assumptions
46
Every node knows its location Positioning devices like GPS
Localization
A source can get the location of the destination
802.11 MAC
Link bidirectionality
7/25/2019 Ruting Protocol for Wsn
47/57
Geographic Routing: Greedy Routing
47
SD
Closest to D
A
- Find neighbors who are the closer to the destination
- Forward the packet to the neighbor closest to the destination
7/25/2019 Ruting Protocol for Wsn
48/57
Benefits of GF
48
A node only needs to remember the location info ofone-hop neighbors
Routing decisions can be dynamically made
7/25/2019 Ruting Protocol for Wsn
49/57
Greedy Forwarding does NOT always work
49
If the network is dense enough that each interiornode has a neighbor in every 2/3 angular sector,GF will always succeed
GF fails
7/25/2019 Ruting Protocol for Wsn
50/57
Energy-Aware Routing
50
Maximise network lifetime (no accepted definition) Communication is the most expensive activity Possible goals include:
Shortest-hop (fewest nodes involved) Lowest energy route Route via highest available energy Distribute energy burden evenly Lowest routing overhead
Distributed algorithms cost energy Changing component state costs energy
NOTE: Read Routing Strategies PPTs after this
7/25/2019 Ruting Protocol for Wsn
51/57
Energy-Aware Routing
51
A destination-initiated reactive protocol
It maintains a set of paths
Choosing paths by means of certain probability
depending on how low the energy consumption is
7/25/2019 Ruting Protocol for Wsn
52/57
Energy-Aware Routing
52
Setup Phase
Controller
Sensor
Directional flooding
10 nJ
30 nJ
p1= 0.75
p2= 0.25
Local Rule
7/25/2019 Ruting Protocol for Wsn
53/57
Energy-Aware Routing
53
Data Communication Phase
1.0 1.0
0.6
0.4
Controller
Sensor0.3
0.7
Each node makes
a local decision
7/25/2019 Ruting Protocol for Wsn
54/57
Attribute-based routing
54
Data-centric approach: Not interested in routing to a particular node or a particular location
Nodes desiring some information need to find nodes that have thatinformation
Attribute-value event record, and associated query
type animal
instance horse
location 35,57
time 1:07:13
type animal
instance horse
location 0,100,100,200
7/25/2019 Ruting Protocol for Wsn
55/57
Directed diffusion
55
Sinks: nodes requesting information Sources: nodes generating information
Interests: records indicating A desire for certain types of information
Frequency with which information desired
Key assumption: Persistence of interests
Approach:
Learn good paths between sources and sinks
Amortize the cost of finding the paths over period of use [IGE00]
7/25/2019 Ruting Protocol for Wsn
56/57
Diffusion of interests and gradients
56
Interests diffuse from the sinks through the sensornetwork
Nodes track unexpired interests
Each node maintains an interest cache Each cache entry has a gradient
Derived from the frequency with which a sink requests repeateddata about an interest
Sink can modify gradients (increase or decrease) depending on
response from neighbors
7/25/2019 Ruting Protocol for Wsn
57/57
Attribute based Routing
Directed Diffusion
Rumor Routing
Geographic hash table
57
top related