A review of routing protocols in wsn

A Review of Routing Protocols in
Wireless Sensor Network

1.Introduction
• WSN: network contain thousands of wireless sensor nodes, collect the
information from their surrounding and sent data to Base Station or sink
node.
• Routing: process of determining type of data can be sent and paths
between source and destination.
• Routing protocols must accomplish high reliability.
• Energy saving is an important design issue in Wireless sensor networks.
• Power consumption and life time.
• Protocols must focus additionally on power conservation to maximize the
network lifetime.
• Efficient routing is a major challenge in the field of WSN.

2. Routing Challenges and Design Issues
• The design of protocol in WSNs is influenced by many challenging factors as:
1- Node deployment:
 application dependent,
 affects the performance of the routing protocol,
 deterministic (manual) or self-organizing (random).
 position of the sink or the cluster-head is very crucial ‫حاسم‬
2- Network dynamics:
 Most of the network architectures assume that sensor nodes are stationary
 sometimes necessary to support the mobility of sinks or cluster-heads
 Route stability becomes an important optimization factor, in addition to energy,
bandwidth etc. as communication from moving nodes is more challenging.

2. Routing Challenges and Design Issues cont.
3-Energy Conservation:
 Multi-hop routing will consume less energy than direct communication (due to the
presence of obstacles).
 Multi-hop routing introduces will increase topology management and medium
access control
 Direct routing would perform well enough if all the nodes were very close to the
sink.
 Most of the time sensors are scattered randomly over an area of interest and multi-
hop routing becomes unavoidable.
4- Fault Tolerance:
 If sensor nodes fail, Routing protocols accommodate ‫يكون‬ formation of new links so
sensor node failure never affect the network.
5- Scalability:
 The number of sensor node in the target area
 protocols should be able to scale to high number of sensor
 protocols should take advantage of the high density of such networks.

4-Hardware Constraint:
 All Sub-units of sensor node must consume extremely low power
 be contained within an extremely small volume.
5-Sensor network topology:
 It must be maintained ‫ثابت‬even with very high node density
6-Environment:
 Nodes should be operating in inaccessible location because of hostile environment.
7-Transmission Media:
 RF or Infrared which is affected by fading and high error rate and affect the operation of
WSNs.
8-Data delivery models:
 In the continuous delivery model, sends data periodically.
 In event-driven and query-driven models, the transmission of data is triggered when an
event occurs or the sink generates a query.
 In hybrid model using a combination of continuous, event-driven and query-driven data
delivery.
 From energy view, routing protocol is influenced by the data delivery model

9-Node capabilities:
 different functionalities depending on the application a node
 Some particular special function as relaying, sensing and aggregation ‫تجميع‬
 engaging the three functionalities at the same time but it might quickly drain
‫يستنزف‬ the energy of that node.
10-Data aggregation/fusion:
 eliminating duplicates
 reduce the traffic, save energy.

3. Routing Techniques in WSN cont.
Path establishment:
1- Proactive protocols:
 compute all the paths before need then store these routes in a routing table in
each node.
 When a path changes, A refreshment has to be propagated throughout the
network.
 If there are a thousands of nodes = huge routing table at each node
 proactive protocols are not suited to WSNs.
2-Reactive protocols:
compute routes only when they are needed.
3-Hybrid protocols:
use a combination of these two ideas.

Network structure
1-Flat Routing (Data Centric Routing protocols):
 It is not feasible ‫مالئم‬to assign global identifiers to each node due to the huge
number of nodes deployed.
 Such lack of global identification along with random deployment of sensor nodes
makes it hard to select a specific set of sensor nodes to be queried.
 Therefore, data is usually transmitted from every sensor node within the
deployment region with significant redundancy ‫.وفرة‬
 This consideration has led to data-centric routing. In data-centric routing, the sink
sends queries to certain regions and waits for data from the sensors located in the
selected regions.

Network structure:
2-Hierarchical protocols:
 Scalability is one of the advantages of WSN protocol.
 Networking clustering can beat additional load and to be able to cover a large area
of interest with good quality.
 Hierarchical routing works in two steps, first step is used to choose cluster heads
and the second step is used for routing.
 To make the WSN more energy efficient, clusters are created and special tasks
(data aggregation, fusion) are assigned to them.
 It increases the overall system scalability, lifetime, and energy efficiency.

Network structure:
3- Location-based protocols:
 In most cases location information is needed in order to calculate the distance
between two particular nodes so that energy consumption can be estimated.
 Generally two techniques are used to find location, one is to find the coordinate of
the neighboring node and other is to use GPS (Global Positioning System).
 Location information can be utilized in routing data in an energy efficient way.

protocol operation:
1-Multipath routing protocols:
 Multiple paths are used to enhance the network performance.
 When the primary path fails between the source and the destination another path
exists.
 That measured the fault tolerance (resilience ‫)مرونة‬ of a protocol.
 The alternate paths are kept alive by sending periodic messages.
 This increases the cost of energy consumption and traffic generation.
 Network reliability can be increased.

protocol operation:
2-Query based routing protocols:
 The destination nodes sent a query for data from a node through the network
 Only node having this data sends back the data.
 Usually these queries are described in natural language, or in high-level query
languages.
3-Negotiation based routing protocols:
 Eliminate redundant data transmissions,
 it uses high level data descriptors through negotiation.
 Based on the resources that are available to them, communication decisions are
taken.
 This consumes more energy and more processing by sending the same data to
different sensor nodes.
 The main idea of negotiation is to suppress duplicate information and prevent
redundant data from being sent by conducting a series of negotiation messages
before the data transmission begins.

protocol operation:
4-QoS-based routing protocols:
 when delivering data to the Base Station, the network has to balance between
energy consumption and data quality.
 Quality of Service metrics as delay, energy, bandwidth, etc.
5-Coherent and non-coherent processing:
 Non-coherent data processing: Nodes will locally process the raw ‫خام‬ data before
being sent to other nodes for further processing. The nodes that perform further
processing are called the aggregators.
 Coherent data processing: The data is forwarded to aggregators after minimum
processing. The minimum processing : time stamping, duplicate suppression, etc.
When all nodes are sources and send their data to the central aggregator node, a
large amount of energy will be consumed and hence this process has a high cost.
One way to lower the energy cost is to limit the number of sources that can send
data to the central aggregator node.

A review of routing protocols in wsn

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