It gives a brief description about the adhoc network applications.

1. EC8702-Ad Hoc and Wireless
Sensor Networks
Prepared by,
Ms.J.Paruvathavardhini(AP/ECE)
Ms.S.Menaga(AP/ECE)
Jai Shriram Engineering College,Tirupur

2. contents
•Commercial Applications
• AD hoc wireless internet
• Issues in designing routing protocol

3. Military Application:
 Useful in communication among a group of soldiers for tactical
operations.
 Useful in the coordination of military objects(air planes or warships)
moving at high speeds.
 For example leader of the soldiers want to give any order to all
soldiers or to a set of selected persons are involved in the operation.
 Used in other services such as location tracking /other satellite
based services.

4. Collaborative and Distributed Computing:
 To give information in a group of peoples using conference.
For example:
 Group of researchers want to share their research among group of
peoples.
 Lecturer distributing notes to the class.
 Sharing of a file among network.

5. Emergency Operations:
 Ad hoc is used in search and rescue operations, crowd control and
commando operations.
 Used in coordinating rescue activities during war or the natural
disaster like earthquakes.
 Conventional communication facilities are destroyed in that case ad
hoc network is used for rescue activities.

6. Wireless Mesh Network:
 Wireless Mesh Network are the ad hoc wireless network that provide
the many alternate path (to reach the destination) for mobile or fixed
nodes/users.
 Quick reconfiguration of the path when the existing path fails due to
node failures.
 Making cost for wireless mesh networks is much less than cellular
networks.
 Possible deployment scenarios are:
 Residential zones
 Highways
 Business Zones
 Important civilian regions
 University campuses

9.  Mesh Network support high data rate, quick and low cost deployment,
enhanced services, high scalability and high availability.
 Deployment and data transfer rate is less.
 Services for smart environment like updating information about the
environment and updating digital map.

10.  A sensor network is a collection of large number of sensor nodes that
are deployed in particular region.
 As we know that the sensor are the tiny devices that have capability to
sensing parameter, processing the data and communicate over the
network.
 A sensing can be periodic or sporadic.
Periodic example- Sensing of environmental factors for the
measurement of parameters such as temperature, humidity and
nuclear radiation.
Sporadic example-Detecting border intrusion , measuring the stress on
critical structures.
 Military, Health Care, Home security and environmental monitoring
are the application areas of wireless sensor network.

11.  Cellular networks – geographical channel reuse.
 Incorporating multi-hop relaying with existing fixed infrastructure
increase the capacity of a cellular network.
 MCNs provide reliability and flexibility.
 Advantages:
Higher capacity due to better channel reuse
Increased flexibility and reliability in routing
Better coverage and connectivity in holes of a cell.

12. AD HOC wireless
Internet

13.  The ad hoc wireless Internet extends the services of the
Internet to the end users over an ad hoc wireless network.
 Some of the applications of the ad hoc wireless Internet are
 wireless mesh networks
 provisioning of temporary Internet services to major
conference venues
 sports venues
 temporary military settlements
 battlefields and
 broadband Internet services in rural regions

15.  The major issues to be considered for a successful ad hoc wireless Internet
are the following:
 Gateways
-Gateway nodes in the ad hoc wireless Internet are the entry points to the
wired Internet, owned and operated by a service provider
-The major part of the service provisioning lies with the gateway nodes.
- Gateways perform the following tasks:
 keeping track of the end users,
 bandwidth management,
 load balancing,
 traffic shaping,
 packet filtering,
 bandwidth fairness, and address,
 service, and location discovery.

16.  Address mobility
-The ad hoc wireless Internet faces the challenge of address mobility.
-This problem is worse here as the nodes operate over multiple wireless
hops.
-Mobile IP can provide temporary alternatives for this
 Routing
-Causes major issue due to dynamic changes in the topology, the presence
of gateways, multi-hop relaying, and the hybrid character of the network.
-The solution for this is to use a separate routing protocol, exploit the
presence of gateway nodes in the wireless part of the ad hoc wireless
Internet

17.  Transport layer protocol
-Solutions for transport layer depends on the in the TCP’S extension.
-Split approaches that use traditional wired TCP can be used for the
wired part and
- A specialized protocol where the gateways act as the intermediate nodes
at which the connections are split can be used for the ad hoc wireless
networks
-The state maintenance overhead at the gateway nodes has to be done
correctly
 Load balancing
- Load balancing techniques are essential to distribute the load so as to
avoid the situation where the gateway nodes become bottleneck nodes

18.  Pricing/billing
-Gateway is the preferred choice for charging the traffic to and from the
Internet.
-Pricing schemes can be used for this purpose.
-Pricing the local traffic
(ie)traffic within the wireless part, that is, it originated and terminated
within the wireless part without passing through the gateway nodes
- It is necessary to have a dedicated, secure, and lightweight
pricing/billing infrastructure installed at every node.
 Provisioning of security
-To avoid potential hackers, who snoop the information sent in air,
security mechanisms should be used.
-Security is a prime factor to perform e-commerce transactions

19.  QoS support
- With the widespread use of voice over IP (VoIP) and growing multimedia
applications over the Internet, provisioning of QoS support in the ad hoc
wireless Internet becomes a very important issue.
 Service, address, and location discovery
- Service discovery in any network refers to the activity of discovering or
identifying the party which provides a particular service or resource.
- Address discovery refers to the services such as those provided by address
resolution protocol (ARP) or domain name service (DNS) operating
within the wireless domain.

20. - Location discovery refers to different activities such as detecting the
location of a particular mobile node in the network or detecting the
geographical location of nodes
-LD can provide enhanced services such as routing of packets, location-
based services, and selective region-wide broadcasts.

21. The major challenges that a routing protocol designed for ad hoc
wireless networks faces are as follows
 Mobility
- The network topology in an ad hoc wireless network is highly dynamic
due to the movement of nodes, hence an on-going session suffers
frequent path breaks.
- Routing protocols for ad hoc wireless networks must be able to perform
efficient and effective mobility management.
 Bandwidth constraint
- In a wireless network, the radio band is limited, and hence the data
rates it can offer are much less than what a wired network can offer.
- This requires that the routing protocols use the bandwidth optimally by
keeping the overhead as low as possible

22.  Error-Prone Shared Broadcast Radio Channel
- The wireless links have time-varying characteristics in terms of link
capacity and link-error probability.
- This requires that the ad hoc wireless network routing protocol
interacts with the MAC layer to find alternate routes through better-
quality links.
 Hidden and Exposed Terminal Problems
- The hidden terminal problem refers to the collision of packets at a
receiving node due to the simultaneous transmission of those nodes
that are not within the direct transmission range of the sender, but are
within the transmission range of the receiver.
- Collision occurs when both nodes transmit packets at the same time
without knowing about the transmission of each other.

23. - The exposed terminal problem refers to the inability of a node which is
blocked due to transmission by a nearby transmitting node to transmit
to another node.
 Resource Constraints
- Two essential and limited resources that form the major constraint for
the nodes in an ad hoc wireless network are battery life and processing
power.
- Devices used in ad hoc wireless networks in most cases require
portability, and hence they also have size and weight constraints along
with the restrictions on the power source.

24.  Characteristics of an Ideal Routing Protocol for Ad Hoc
Wireless Networks
-A routing protocol for ad hoc wireless networks should have the
following characteristics:
1.Fully distributed routing, no centralized routing
2.Must adapt to frequent topology changes
3. Minimum connection set up time is desired
4. Local maintenance
5. Minimum packet collision
6. Convergence must be quick
7. Must be loop-free and free from stale routes
8. It must optimally use scarce resources such as bandwidth, computing
power, memory, and battery power.
9. It must cover all the optimal routes in the network topology
10. It should provide good QoS.