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Outline :
introduction
. The wireless communication landscape has been changing dramatically driven by rapid advances in technologies and the greater selection of new wireless services and applications.
• The major goal of wireless communication is to allow a user to have access to the capabilities of global networks at any time without regard to location or mobility.
• Types Of Wireless Networks :
• Infrastructure-based networks
• “A network with pre-constructed infrastructure that is made of fixed and wired network nodes and gateways, with typically, network services delivered via these pre-configured infrastructures ”.
• MANET – Mobile Ad hoc Networks
• Challenges Of Wireless Networks:
• Forces Driving Wireless Technology :
• Two major goals of Wireless Technology :
•
Second Generation Digital Cellular Systems: (Launched In 1991)
• Limitations of 2G
• Low transfer rates ( average 10Kbps)
• Low efficiency for packet-switched services
• Multiple standards
• Solutions came in the form of 2.5G HSCSD, GPRS, EDGE (average 384Kbps)
Third Generation Systems: (Launched in 2001)
3G systems
– Goal: High speed always on wireless data access and unified universal standard
– Time frame: 2002-
– Two competing standards
– One based on GSM, named as 3GPP (CDMA2000)
– Other based on IS-95 named 3GPP2 (WCDMA)
– Move from circuit switching to packet switching
– Enhanced data rates of 2-20Mbps
Fourth Generation (4G): (Expected by 2011)
4G systems
– Term used to denote all future systems
– Goal: High mobility, High data rate, IP based network
– Hybrid network that can interoperate with other networks
• Vision of 4G:
• The vision of 4G mobile is :
 Accelerated growth in the demand for broadband wireless connectivity.
 Ensure seamless services provisioning across a multitude of wireless systems.
 Provide optimum delivery of the user’s wanted service.
 Cope with the expected growth in Internet – based communication, new spectrum frontiers
and new market opportunities.
Features of 4G Wireless Systems
4G Wireless network capabilities :
• View of 4G mobile and Wireless Communication
Functions:
 Higher transmission rate up to 100Mbps.
 Flexible to advanced Internet ,QoS control
 Enhanced Security
 Seamless operation across network
 Multiple broadband access.
3G Vs 4G
• Trends of Wireless Technologies
• General Trends : Bandwidth - Personal Wireless
• Mobile Ad hoc Networks
 Are envisioned to become an important part of overall next generation wireless functionalities.
Characteristics Of Manets :
• Does not rely on a fixed infrastructure for its operation
• Autonomous Transitory association of mobile nodes
• It can be rapidly deployed with user intervention
• Need not to operate in a stand alone fashion but can be attached to the Internet or Cellular networks.
• Devices are free to join or leave the network and they may randomly, possibly resulting in rapid and unpredictable changes
• Capabilities:
Application of MANETs
Sources of failure in MANETs
 Topological Failures: It includes:
 Link failure due to power drainage of one or more relay nodes;
 A node is powered off ;and/or a node is moved out of the reachable area
 Channel failures :It includes
 Long fading spell
 Additive or multiplicative noise signal
 Protocol Failures : It includes
 Lack of congestion mechanisms on one or more links.
 Lack of Scalability to the number of users in ad hoc group.
 A relay node has a data filter (e.g., firewall)
 Security failures owing to unprotected access to any terminal in the network
• This scenario raises a number of interesting and difficult algorithmic issues in different areas such as routing, location management, resource allocation, information retrieval, network connectivity, reliability, security and energy consumption.
Functions within Mobile ad hoc networks:
• Ad Hoc Routing Protocol:
• QoS:
• Types Of Routing Protocol:
There are mainly two schemes:
• Proactive routing protocol:
 known as Table driven
 every node continuously maintains the complete routing information of the network
e.g. Distance Vector Routing , Link State Routing etc.
• Reactive routing protocol:
 known as Demand driven
 nodes only maintain routes to active destinations.
e.g. Dynamic Source Routing etc.
• Complexities and Challenges of Manets:
• Future Challenges of Manets with 4G :
• Wireless Technology- Key to access
Rural Area
Wireless Technologies have been instrumental in bringing new and critical telecommunications services to rural areas, enhancing the lives of rural residents and boosting the productivity of local businesses.
• Wireless is the key technology for wiring India
• Wireless networking are increasingly becoming the solution to getting “last–mile” broadband connectivity in rural areas and semi rural areas.
• Advantages of wireless networking in rural areas
• Saves the high cabling cost of the wired alternative.
• Ease in installation in inaccessible terrains
• It can also reduce installation time, where installation of cabling is often time consuming.
• Increased reliability
• Support portability
Challenges in deploying land-line connectivity in rural areas are:
• Emerging Technologies in Rural Areas:
• 3G Wireless technologies
• Rural Local Multipoint Distribution(LMDs)
• WLL services
• Rural satellite services
• State wide multiple agency wireless network deployment