adhoc wireless networks and its issues.pdf

It describes the major issues in designing the Ad-hoc network

1. EC 8702-AD-HOCANDWIRELESSSENSOR
NETWORK
JAISHRIRAMENGINEERINGCOLLEGE, TIRUPUR
Prepared by,
Ms.S.Menaga,AP/ECE
Ms.J.Paruvathavardhini,AP/ECE

2. UNIT-I
AD-HOC NETWORKS-INTRODUCTION&
ROUTINGPROTOCOLS
CONTENTS
Introduction-Ad hoc Wireless Networks
Elements of Ad hoc Wireless Networks
Issues in Ad hoc wireless networks

3. INTRODUCTION-AD HOC WIRELESS NETWORKS
Ad hoc Networks
A Basic Service Set without an Access Point is called an ad hoc
network/Infrastrucelessnetwork.
A Basic Service Set without an Access Point is called an infrastructure
network.
-BS/AP
Infrastructure –BSS with AP Ad hoc–BSS without AP

4. WIRELESS AD HOC NETWORKS
Ad hoc Networks-Temporary network composed of mobile hosts that
communicate with other nodes through wireless medium.
Infrastructurelessnetwork(no Access point(AP) and Base Station (BS))
Each node acts as a router for multi-hop routing.
Self-organizing network without any fixed infrastructure.
Started from University of Hawaii –invented ALOHA net in 1970
Develop Ethernet by Robert Metcalfe and PRNetby DARPA in 1970
Cooperative nodes (wireless)
Each node decode-and-forward packets for other nodes
Multi-hop packet forwarding through wireless links
Proactive/reactive/hybrid routing protocols
Most works based on CSMA/CA to solve the interference problem
IEEE 802.11 MAC

5. CELLULARANDADHOCWIRELESS
NETWORKS

6. CELLULARVSADHOCWIRELESS
NETWORKS
Cellular Networks AdhocWireless Networks
Infrastructure Networks InfrastructurelessNetworks
Single hop relaying Multihoprelaying
Static backbone network topology. Highly dynamic network topologies
High setup costs Cost effective
Circuit-switched Packet-switched
Centralized routing Distributed routing
Guaranteed bandwidth Shared radiochannel
Applications mainly for civilianand
commercial sectors.
Applications includebattlefields,
emergency research, rescue operations
and collaborative computing.

7. ELEMENTS OF AD HOC WIRELESS NETWORKS
ElementsofAdhocWirelessNetworks
Categoryofwirelessnetworks,collectionoftwoormoremobile
hostswhichcommunicatewitheachotherwithoutthesupportof
anyfixedinfrastructure.
Anadhocwirelessnetworkisself-organizingandadaptive.
Thismeansthataformednetworkcanbede-formedon-the-
flywithouttheneedforanysystemadministration.
Nofixedradiobasestations,nowiresandfixedrouters.

8. CONTD..
A wireless ad-hoc network is a decentralized type of wireless
network.
Routingandresourcemanagementaredoneindistributedmanner.
Moreintelligentnoderequiredinthenetworkcanfunctionbothasa
networkhostfortransmitting,receivingdataandasanetworkrouterfor
routingpacketsfromothernodes.
Thenetworkisadhocbecauseitdoesnotdependonapre-existing
infrastructure,suchasroutersinwirednetworksoraccesspointsin
managed(infrastructure)wirelessnetworks.
Inadditiontotheclassicrouting,adhocnetworkscanusefloodingfor
forwardingthedata.

9. ISSUES IN AD HOC WIRELESS
NETWORKS
Adhocwirelessnodesareindifferentformssuchaslaptops,palmtop,
Internetmobilephone-thecomputation,storage,interoperabilityofthese
deviceswillvarytremendously.
Themajorissuesthataffectthedesign,deployment,andperformanceof
anAdhocwirelesssystemareasfollows:
1.Mediumaccessscheme 9.Energymanagement
2.Routing 10.Addressingandservicediscovery
3.Multicasting 11.Scalability
4.Transportlayerprotocol 12.Deploymentconsiderations
5.Pricingscheme
6.Qualityofserviceprovisioning
7.SelfOrganization
8.Security

10. 1.MEDIUMACCESSSCHEME
MAC provides a distributed arbitration for the shared channel for
transmission of packets.
Wireless networks depends on MAC protocol for better
performance, the major issues are as follows:
Distributed operation
-works in uncentralizedcoordination
-design should be fully distributed involving minimum control
overhead.
-in polling-based MACprotocols, partial coordination is required.
Synchronization
-Time synchronization is important for TDMA based systems for
management of transmission and reception slots
-uses resources such as bandwidth and battery power.
-control packets used for synchronization increases collisions in
the network.

11. CONTD…
Hidden terminals
-They are nodes hidden from the sender of a data transmission
session, but are reachable to the receiver of the session
-Cause collisions at the receiver node,
-The presence of hidden terminals reduce the throughput of a MAC
protocol,
-so MAC should be designed in a way to avoid this issue
Exposed terminals
-Nodes in the transmission range of the sender of an on-going
session
-Not allowed to make transmission
-They should be allowed to make transmission to improve MAC
protocol efficiency

12. CONTD…
Throughput
-MACprotocolshouldimprovethethroughputoftheadhoc
networkby
-Minimizingtheoccurrenceofcollisions,maximizingchannel
utilization,andminimizingcontroloverhead.
Access Delay
-MACprotocalshouldattempttominimizetheaveragedelay
thatanypacketexperiencestogettransmitted
Fairness( provides equal or weighted share of BW to all nodes)
-Two types node based or flow based
-Node basedprovides equal BW share for competing nodes
-Flow basedequal share for competing transfer sessions
-Equal fairness is important as multihoprelaying is done
-Unfairness leads to draining of resources.

13. CONTD…
Real-time traffic support
-Time-sensitive traffic such as voice, video, and real-time data
requires explicit support from the MAC protocol.
Resource reservation
-MACprotocolshouldbeabletoprovidemechanismsforsupporting
resourcereservationandQoSprovisioninglike
-Bandwidth,delay,andjitterrequiresreservationofresourcessuch
asbandwidth,bufferspace,andprocessingpower
Ability to measure resource availability
-The MAC protocol should be able to provide an estimation of
resource availability at every node(ie)for making congestion-control
decisions, like BW management & call admission control

14. CONTD…
Capability for power control
-Tx.Powercontrolreducesenergyconsumptionatnodes
-Decreasesinterferenceatneighbouringnodesandimproves
frequencyreuse
Adaptive rate control(variation in data bit rate)
-MACprotocolcanmakeuseofahighdataratewhenthesender
andreceiverarenearby
-Reducethedatarateastheymoveawayfromeachother.
Use of directional antennas
-Provides increased spectrum reuse, reduction in interference, and
reduced power consumption

15. 2.ROUTING
The responsibilities of a routing protocol include exchanging the
route information
Finding a feasible path to a destination based on criteria such as
hop length, minimum power required and lifetime of the wireless link
Gathering information about the path breaks
Mending the broken paths expending minimum processing power
and bandwidth
Utilizing minimum bandwidth

16. CONTD…
The major challenges that a routing protocol faces are as follows:
Mobility
-The mobility of nodes results in frequent path breaks, packet
collisions, transient loops, stale routing information, and difficulty in
resource reservation.
-A good routing protocol should be able to efficiently solve all the above
issues.
Bandwidth constraint
-The bandwidth available per wireless link depends on the number of
nodes and the traffic they handle. Thus only a fraction of the total
bandwidth is available for every node.
Error prone and shared channel
-BER is very high for wireless channel, so efficiency can be improved
by
-Considering of the state of the wireless link, signal-to-noise ratio, and
path loss

17. CONTD…
Location –dependent contention
-The load of the channel varies with no. of nodes
-Increases contention with the increase in nodes, this increases
collision and wastage of BW.
-So proper mechanisms should be provided to distribute load evenly
Other resource constraints
-The constraints on resources such as computing power, battery
power, and buffer storage also limit the capability of a routing
protocol.

18. CONTD…
The major requirements of a routing protocol in ad hoc wireless
networks are the following:
Minimum route acquisition delay
-node that does not have a route to a particular destination node
should be as minimal as possible
-this delay may vary with the size of the network and the network load.
Quick route reconfiguration
-unpredictable changes in the topology of the network requires routing
protocol be able to quickly perform route reconfiguration
-this avoids path breaks and subsequent packet losses.

19. CONTD…
Loop-free routing
-due to the random movement of nodes, transient loops may form in the
route thus established.
-a routing protocol should detect such transient routing loops and take
corrective actions.
Distributed routing approach
-ad hoc is a distributed wireless network
-centralized routing consumes a large BW
Minimum control overhead
-control packets used for finding and maintaining routes should be
maintained minimal as it consumes large BW and causes collision.

20. CONTD…
Scalability
-forabetterscalingofthenetwork,itrequiresminimizationofcontrol
overheadandadaptationoftheroutingprotocoltothenetworksize.
Provisioning of QoS
-parameterscanbebandwidth,delay,jitter,packetdeliveryratio,and
throughputtoprovidecertainlevelofQoStothenodes
Support for time-sensitive traffic
-The routing protocol should be able to support both hard realtimeand
soft real-time traffic.
Security and privacy
-must be resilient to threats and vulnerabilities
-it should avoid resource consumption, denial of-service,
impersonation, and similar attacks

21. 3.MULTICASTING
Multicasting plays an important role in emergency search-and-rescue
operations and military communication.
In such an environment, nodes form groups to carry out point-to-
multipoint and multipoint-to-multipoint voice and data communication.
The arbitrary movement of nodes changes the topology dynamically
in an unpredictable manner
Usage of traditional tree based structure like core based trees (CBT),
protocol independent multicast (PIM), and distance vector multicast
routing protocol (DVMRP) is highly unstable.
The use of single-link connectivity among the nodes in a multicast
group results in a tree-shaped multicast routing topology
This provides high multicast efficiency, with low packet delivery ratio
due to the frequent tree breaks.
Provisioning of multiple links among the nodes in an ad hoc network
results in a mesh-shaped structure, which work well in a high-mobility
environment.

22. CONTD…
The major issues in designing multicast routing protocols are as
follows:
Robustness
-The multicast routing protocol must be able to recover and
reconfigure quickly from potential mobility-induced link breaks
-thus making it suitable for use in highly dynamic environments.
Efficiency
-A multicast protocol should make a minimum number of
transmissions to deliver a data packet to all the group members.
Control overhead
-The scarce bandwidth availability in ad hoc wireless networks
demands minimal control overhead for the multicast session.

23. CONTD…
Quality of service
-QoSsupport is essential in multicast routing as the data transferred in
a multicast session is time-sensitive.
Efficient group management:
-the process of accepting multicast session members and maintaining
the connectivity among them until the session expires.
-This process of group management needs to be performed with
minimal exchange of control messages.
Scalability
-The multicast routing protocol should be able to scale for a network
with a large number of nodes.
Security
-Authentication of session members and prevention of non-members
from gaining unauthorized information play a major role in military
communications.

24. 4.TRANSPORTLAYERPROTOCOLS
The main objectives of the transport layer protocols include
-setting up and maintaining end-toendconnections,
-reliable end-to-end delivery of data packets,
-flow control, and congestion control
Simple connectionless protocol like UDP does not perform any
actions like flow or congestion control nor reliable data transfer
It does not take into account the current network status such as
congestion at the intermediate links, the rate of collision, or other
similar factors affecting the network throughput.
It increases the contention of the network
Eg: in an ad hoc wireless network that employs a contention-based
MAC protocol, nodes in a high-contention region experience
several backoffstates, resulting in an increased number of
collisions and a high latency.

25. CONTD…
Connectionless transport layer protocols, unaware of this situation,
increase the load in the network, degrading the network
performance.
a reliable connection-orientedtransport layer protocol such TCP
faces performance degradation due to frequent path breaks,
presence of stale routing information, high channel error rate, and
frequent network partitions.
This occurs due to mobility of nodes in low Txrange.
Each path break results in route re-configuration that depends on
the routing protocol employed.
Finding new route takes more time than the Tx. Time. Sometimes if
no new route is found, the packets has to be re-transmitted.
Or congestion control algorithm has to be executed, this reduces the
congestion window size and this results in low throughput.

26. ISSUES
Thelatency associated with the reconfiguration of a broken path and
the use of route caches result in stale route information at the nodes.
Hence the packets will be forwarded through multiple paths to a
destination, causing an increase in the number of out-of-order
packets.
Multipath routing protocols such as temporally-ordered routing
algorithm (TORA) and split multipath routing (SMR) protocols
employ multiple paths between a source destination pair.
Out-of-order packet arrivals force the receiver of the TCP connection
to generate duplicate acknowledgments (ACKs).
On receiving duplicate ACKs, the sender invokes the congestion
control algorithm.

27. CONTD…
Wirelesschannelsareinherentlyunreliableduetothehigh
probabilityoferrorscausedbyinterference.
Inadditiontotheerrorduetothechannelnoise,thepresenceof
hiddenterminalsalsocontributestotheincreasedlossofTCPdata
packetsorACKs.
WhentheTCPACKisdelayedmorethantheround-triptimeout,
thecongestioncontrolalgorithmisinvoked

28. CONTD…
Duetothemobilityofthenodes,adhocwirelessnetworksfrequently
experienceisolationofnodesfromtherestofthenetworkor
occurrenceofpartitionsinthenetwork.
WhenaTCPconnectionspansacrossmultiplepartitions,
-thatis,thesenderandreceiveroftheconnectionareintwodifferent
partitions,allthepacketsgetdropped.
Thistendstobemoreseriouswhenthepartitionsexistforalong
duration,resultinginmultipleretransmissionsoftheTCPpackets
andsubsequentincreaseintheretransmissiontimers.
Soalltheseissueslikelatency,Occurrenceofpartitions,probability
oferrorshastobeavoidedintransportlayerwhiledesigningthe
routingprotocol

29. 5.PRICING SCHEME
An ad hoc wireless network's functioning depends on the presence
and willingness of relaying nodes .
Eg: Assume that an optimal route from node A to node B passes through
node C, and if node C is not powered on, then node A will have to set
up a costlier and non-optima l route to B.
The non-optimal path consumes more resources(battery charge and
computing power) and affects the throughput of the system.
Throughput-No of packets reached successfully in a given time
period.
Proper Compensation required -pricing schemes that incorporate
service compensation or service reimbursement.
Not required for applications like military missions, rescue operations,
and law enforcement.
Required for commercial deployment.

30. 6.QUALITY OF SERVICE PROVISIONING
Measure the performance level of services offered by a service
provider or a network to the user.
Quality of service provisioning includes
QoS parameters
QoS-aware routing
QoS frameworks
QoS PARAMETERS
QoS parameters are differ from application to application, based on
the requirements.
For example, for multimedia applications, the bandwidth and delay
are the key parameters, whereas military applications have the
additional requirements of security and reliability.
In a sensor network the transmission among them the nodes
results in minimum energy consumption, hence battery life and
energy conservation can be the prime QoS parameters here.

31. CONTD..
QOS-AWARE ROUTING
A QoS-aware routing protocol is to have the routing use QoS
parameters for finding a path.
Consider the following parameters for routing decisions
Throughput
packet delivery ratio
reliability, delay
delay jitter
packet loss rate
bit error rate
path loss.
For example, the QoS parameter is bandwidth, the routing protocol
utilizes the available bandwidth at every link to select a path with
necessary bandwidth.
Demand-Reserve the required amount of bandwidth for that particular
connection.

32. QOS FRAMEWORK
To provide the promised services to each user or application.
 QoS service model -defines the way user requirements are
served.
Various components of QoS Framework:
QoS routing -To find all or some feasible paths in the network that
can satisfy user requirements,
QoS signaling-Resource reservation required by the user or
application
QoS medium access control, connection admission control, and
scheduling schemes pertaining to that service model.
The QoS modules such as routing protocol, signaling protocol, and
resource management should react promptly according to changes in
the network state (topology change in ad hoc wireless networks) and
flow state (change in end-to-end view of service delivered).

33. 7.SELF-ORGANIZATION
An ad hoc wireless network should exhibit is organizing and
maintaining the network by itself.
Activities required to perform for self-organization are neighbor
discovery, topology organization, and topology reorganization.
Neighbor discovery phase -Every node in the network should aware of
its neighbors by using periodic transmission of beacon packets.
Topology organization phase –Maintaining topological information by
every node in the network by gathers information about the entire
network part of the network.
Topology reorganization phase -Updating the topology information by
incorporating the topological changes occurred in the network due to
the mobility of nodes, failure of nodes, or complete depletion of power
sources of the nodes.

34. CONTD..
The reorganization consists of two major activities:
1.periodic exchange –Exchanging of topological information
periodically.
2.Aperiodic exchange-Exchanging of topological information
once changes in the network (Adaptability)
 Network partitioning and merging of two existing partitions
require major topological reorganization.
 Ad hoc wireless networks should be able to perform self-
organization quickly and efficiently in a way transparent to the
user and the application.

35. 8.SECURITY
In wireless Ad hoc networks the packets are more vulnerable to various
attacks than wired networks.
ATTACKS
ACTIVE ATTACKS: Disrupt the
operation of the network.
PASSIVE ATTACKS: The
attacker intercepts the transit
information with the intention
of reading and analyzing the
information not for altering it.INTERNAL ATTACKS-
Executed by nodes
belonging to the same
network
EXTERNAL ATTACKS-
Executed by nodes
belonging to other
network

36. SECURITYTHREATSINADHOCWIRELESS
NETWORKS ARE:
DENIALOFSERVICE:Theattackeffectedbymakingthe
networkresourceunavailableforservicetoothernodes,either
byconsumingthebandwidthorbyoverloadingthesystem,is
knownasdenialofservice(DoS).
RESOURCE CONSUMPTION: Aiming at consuming resources
available in the network
Energy depletion -Depleting the battery power of critical
nodes by directing unnecessary traffic through them.
Buffer overflow -Attack is carried out either by filling the
routing table with unwanted routing entries or by consuming
the data packet buffer space with unwanted data.
-Attack lead to a large number of data
packets being dropped, leading to the loss of critical
information.

37. CONTD…
HOSTIMPERSONATION:Acompromisedinternalnodecanact
asanothernodeandrespondwithappropriatecontrolpacketsto
createwrongrouteentries,andcanterminatethetrafficmeantfor
theintendeddestinationnode.
INFORMATIONDISCLOSURE:Acompromisednodecanactas
aninformerbydeliberatedisclosureofconfidentialinformationto
unauthorizednodes.
INTERFERENCE:Tojamthewirelesscommunicationbycreating
awide-spectrumnoise.
Donebyusingasinglewide-bandjammer,
sweepingacrossthespectrum.

38. 9. ADDRESSINGANDSERVICEDISCOVERY
Ifnodeinthenetworksneedtoparticipateincommunication,auto-
configuration(nocentralizedco-ordinator)ofaddressesisrequired
toallocatenon-duplicateaddressestothenodes.
Innetworkswherethetopologyishighlydynamic,frequent
partitioningandmergingofnetworkcomponentsrequireduplicate
address-detectionmechanismsinordertomaintainunique
addressingthroughouttheconnectedpartsofthenetwork.
Serviceadvertisementmechanismarerequiredtolocateservices.
Provisioningofcertainkindsofservicesdemandsauthentication,
billing,andprivacythatinturnrequiretheservicediscovery
protocolstobeseparatedfromthenetworklayerprotocols.

39. 10. ENERGY MANAGEMENT
ENERGY MANAGEMENT:
Process of managing the sources and consumers of energy in a node /
network.
To enhancing the lifetime of the network.
ENERGY MANAGEMENT
TRANSMISSION
POWER
MANAGEMENT
BATTERY
ENERGY
MANAGEMENT
PROCESSOR
POWER
MANAGEMENT
DEVICES
POWER
MANAGEMENT

40. 1.TRANSMISSION POWER MANAGEMENT
Thepowerconsumedbyamobilenodeisdeterminedbyseveral
factorssuchasthestateofoperation,thetransmissionpower,andthe
technologyusedfortheRFcircuitry.
Thestateofoperationreferstothetransmit,receive,andsleepmodes
oftheoperation.Thetransmissionpowerisdeterminedbythe
reachabilityrequirementofthenetwork,theroutingprotocol,andthe
MACprotocolemployed.
TheRFhardwaredesignshouldensureminimumpowerconsumption
inallthethreestatesofoperation.
Powerconservationresponsibilityliesacrossthedatalink,network,
transport,andapplicationlayers.
Bydesigningadatalinklayerprotocolthatreducesunnecessary
retransmissions,bypreventingcollisions,byswitchingtostandbymode
orsleepmode.

41. CONTD..
Thenetworklayerroutingprotocolscanconsiderbatterylifeand
relayingloadoftheintermediatenodes.
Atthetransportlayer,reducingthenumberofretransmissions,
andrecognizingandhandlingthereasonbehindthepacketlosses
locally,canbeincorporatedintotheprotocols.
Attheapplicationlayer,thepowerconsumptionvarieswith
applications.Inamobilecomputer,theimage/video
processing/playbacksoftwareand3Dgamingsoftwareconsume
higherpowerthanotherapplications.
Henceapplicationsoftwaredevelopedformobilecomputers
shouldtakeintoaccounttheaspectofpowerconsumptionaswell.

42. 2.BATTERY ENERGY MANAGEMENT
Aimedatextendingthebatterylifeofanodebytakingadvantage
ofitschemicalproperties,dischargepatterns,andbytheselection
ofabatteryfromasetofbatteriesthatisavailableforredundancy.
Designingofefficientembeddedchargecontrollersinthebattery
pack.
3.PROCESSOR POWERMANAGEMENT
Theclockspeedandinstructionexecutiontimeaffectpower
consumption.
TurnofftheCPUifthemachineisidleandturnonbyuser
interaction.

43. 4.DEVICES POWER MANAGEMENT
Reducingpowerconsumptionbymanagingthedeviceintelligently.
Advancedpowermanagementfeaturesbuiltintotheoperating
systemandapplicationsoftware'sformanagingdeviceseffectively.

44. 11.SCALABILITY
Commercialdeploymentsofadhocwirelessnetworksthatinclude
wirelessmeshnetworksshowearlytrendsforawidespread
installationofadhocwirelessnetworksformainstreamwireless
communication
Thelatencyofpath-findinginvolvedwithanon-demandrouting
protocolinalargeadhocwirelessnetworkmaybeunacceptably
high.
Similarly,theperiodicroutingoverheadinvolvedinatable-driven
routingprotocolmayconsumeasignificantamountofbandwidthin
suchlargenetworks
Hybridarchitecturesthatcombinethemulti-hopradiorelayinginthe
presenceofinfrastructuremayimprovescalability.

45. 12.DEPLOYMENTCONSIDERATION
Thedeploymentofadhocwirelessnetworksgoodamountof
planningandestimationoffuturetrafficgrowthoveranylinkinthe
network.
Thetime-consumingplanningstageisfollowedbytheactual
deploymentofthenetwork.
Thedeploymentofacommercialadhocwirelessnetworkhasthe
followingbenefitswhencomparedtowirednetworks:
Lowcostofdeployment
-Theuseofmulti-hopwirelessrelayingdoesnotrequireany
cablestobelayed.Hencethecostinvolvedismuchlowerthan
thatofwirednetworks.

46. CONTD..
Incremental deployment
-IncommercialwirelessWANsbasedonadhocwirelessnetworks,
deploymentcanbeperformedincrementallyovergeographicalregions
ofthecity.
-Thedeployedpartofthenetworkstartsfunctioningimmediatelyafterthe
minimumconfigurationisdone
Shortdeploymenttime
-Comparedtowirednetworks,thedeploymenttimeisconsiderablyless
duetotheabsenceofanywiredlinks
Reconfigurability
-Thecostinvolvedinreconfiguringawirednetworkcoveringa
metropolitanareanetwork(MAN)isveryhigh
-Theincrementaldeploymentofadhocwirelessnetworksmight
demandchangesinthetopologyofthefixedpart

47. CONTD…
The following are the major issues to be considered in deploying an
ad hoc wireless network:
Scenario of deployment
The scenario of deployment assumes significance because the
capability required for a mobile node varies with the environment
in which it is used.
Some of the different scenarios in which the deployment issues
vary widely:
Military deployment
-The military deployment of an ad hoc wireless network may be
datacentric(e.g., a wireless sensor network) or
-user-centric (e.g., soldiers or armored vehicles carrying soldiers
equipped with wireless communication devices)

48. CONTD…
Emergency operations deployment
-Thiskindofapplicationscenariodemandsaquickdeploymentof
rescuepersonnelequippedwithhand-heldcommunication
equipment.
Commercial wide-area deployment
-Theaimistoprovideanalternatecommunicationinfrastructurefor
inurbanareasand
-areaswhereatraditionalcellularbasestationcannothandlethe
trafficvolume.
-providesverylowcostperbittransferred
-Addressing,configuration,positioningofrelayingnodes,
redundancyofnodes,andpowersourcesarethemajorissuesin
deployment.
-Billing,provisioningofQoS,security,andhandlingmobilityare
majorissuesthattheserviceprovidersneedtoaddress.

49. CONTD…
Home network deployment
-Itneedstoconsiderthelimitedrangeofthedevicesthataretobe
connectedbythenetwork
-placingthenodesproperlywillavoidissuesduetopartitioning
-propernetworktopologyshouldbedecided
Required longevity of network
-to increase the longevity of the network, battery power can be used or
fixed radio relaying equipment with regenerative power sources can be
deployed.
-the mesh connectivity should be planned in such a way that the harsh
atmospheric factors do not create network partitions.
Area of coverage
-some nodes will be fixed and the network topology is partially or fully
fixed, the coverage can be enhanced by means of directional antennas

50. CONTD…
Service availability
-Availabilityassumessignificancebothinafullymobileadhoc
wirelessnetworkusedfortacticalcommunicationand
-inpartiallyfixedadhocwirelessnetworksusedincommercial
communicationinfrastructuresuchaswirelessmeshnetworks
Operational integration with other infrastructure
-itisconsideredforimprovingtheperformanceorgatheringadditional
information,orforprovidingbetterQoS
-Inthemilitaryenvironment,integrationofadhocwirelessnetworks
withsatellitenetworksorUAVsimprovesthecapability
-theavailabilityofGPScanbeobtainedasaresourcefornetwork
synchronizationandgeographicalpositioning
-smoothhand-offsshouldbeplanned

51. CONTD…
Choice of protocols
-Thechoiceofprotocolsatdifferentlayersoftheprotocolstackistobe
donetakingintoconsiderationthedeploymentscenario
-eg:formilitaryapplicationsCDMA-basedMACprotocolwillbebest
suited
-itshouldgivebettersecurity
-suchasinthesearchoperationintheundergroundmaynotnotbe
supportedbyGPS,soproperprotocolshouldbeselected
-Theperiodicbeacons,orroutingupdates,drainthebatterywithtime
butbatterypowerisnotamatterinmilitaryapplications
-theprotocolsshouldmakeuseofthefixednodestoavoidunstable
pathsduetothemobilityoftherelayingnodes.
-atthetransportlayer,eitherconnectionorientedorconnectionless
protocolcanbeadapted
-similarly,alltheissuesresponsibleforpacketlosshastobe
consideredandproperactionsmustbetakeninthehigherlayer.

52. For the rest of the unit follow our next post.