Mobile Ad Hoc Networking, MESH Networking, WiMAX

1
Mobile Ad Hoc Networking, MESH Networking, Wi-MAX
2
Mobile Ad Hoc Networks (MANETs)

• Dynamic network of autonomous mobile nodes
• Uses wireless links without existing
  infrastructure
• Does not use centralized administration
• Dynamic network leads to high rate of topology
  changes
• Topology changes occur both rapidly and
  unexpectedly
• MANETs are often referred to as multihop wireless
  ad hoc networks

3
MANETs

• Capable of extending network service to areas
  without existing infrastructure
• High expectations of future capabilities
• Large volume of existing research
• Expected to be a key element of 4G wireless
  network architecture
• MANET capabilities are expected to be an overall
  driving force for next-generation wireless
  functionalities

4
MANET Extending the Infrastructure
5
Key Elements of MANETs

• Formed dynamically through the cooperation of
  independent nodes
• Nodes do not have any pre-specified roles
• Nodes make decision independently based on the
  current network situation
• Nodes are expected to behave as routers
• As routers, nodes must assist in discovery and
  maintenance of network routes

6
Formation of a MANET

• Mobile Ad Network HOME

7
MANET Design complexities Constraints

• Infrastructureless with distributed management
• Frequent and unpredictable topology changes
• Physical layer limitation
• Limited link bandwidth and quality
• Variation in node capabilities
• Energy Considerations
• Network reliability
• Network security
• Network scalability
• Quality of service

8
MANET Management

• Multihop network each device must carry burden
  of routing packets from source to destination
• Each Node handles part of the management of the
  network
• Fault detection is extremely difficult because of
  the distributed design

9
MANAET Distributed Management
10
MANET Topology

• Topology changes occur with every move of a
  mobile node
• Every topology change results in route changes
• Route changes lead to network partitions and in
  most instances some packet losses

11
MANET Physical Layer

• Limited wireless range and shared frequency space
  leads to specific mobile ad hoc problems
• High risk of collisions and packet losses
• Hidden terminal problems
• Exposed terminal problem

12
Collision Risk and Packet Loss
B
A
C

• Node A and Node B simultaneously try to
  communicate with Node C. Their traffic collides
  and both packets are lost at Node C.

13
Hidden Terminal
14
Exposed Terminal
15
MANET Congestion Control
Adapted Ready-to-Send (RTS)/Clear-to-Send (CTS)
protocols are the current resolutions to MANET
congestion control, hidden terminal and exposed
terminal problems.
16
MANET Bandwidth Constraints

• Bandwidth used by MANETs has a wide range of
  capacity levels.
• Wireless bandwidth in general is more error-prone
  than wired links.
• Wireless bandwidth in general is more insecure
  than wired links.
• These factors lead to lower capacity throughput
  than equivalent wired links.
• The lower capacity wireless links lead to higher
  congestion problems.

17
MANET Node Variability

• Nodes may have one or more radio interfaces of
  varying transmission capabilities
• Node radios may operate in different frequency
  bands
• Node radio capabilities may result in asymmetric
  links
• Node hardware and software configurations can
  affect processing capabilities

18
MANET Node Variability
19
MANET Energy Constraints

• Link Distance
• Controlled through topology management
• Goal is to reduce overall network power
  consumption as much as possible through
  assignment of per node transmit power levels
• Routing Protocols
• Minimizing routing paths reduces power needed to
  send a packet end-to-end
• Transmit power levels can greatly affect the
  ability of the network to control congestion
• Hidden terminal problems arise

20
MANET Power Considerations
21
MANET Reliability

• Reliability occurs by routing and forwarding
  packets
• Network overload
• Misbehaving nodes
• Broken links
• No centralized management makes these problems
  difficult to detect and isolate
• Reliability thus must rely on properly designed
  protocols

22
MANET Security

• Mobile networks are physically insecure
• Distributed management means overall security is
  dependent on individual node security
• MANET security considerations
• Confidentiality prevent eavesdropping
• Access control protecting the wireless
  infrastructure
• Data integrity preventing tampering of traffic
• Denial of service

23
Wireless Eavesdropping

• Wireless eavesdropping can be performed by anyone
  who has a radio receiver that is compatible with
  the signaling used by the Ad Hoc network

24
MANET Scalability

• Scalability is critical to the successful
  deployment of a MANET
• Factors affecting MANET scalability
• Addressing
• Routing
• Location management
• Configuration management
• Interoperability
• Security
• High-capacity wireless technologies

25
MANET Service Quality

• Quality of Service is of key importance to all a
  networks
• MANETs makes the task of maintaining QoS more
  difficult

26
MANET Applications

• Tactical Networks Military communications and
  operations control in battlefield environments.
• Sensor Networks Collection of embedded sensor
  devices used to collect real-time data to
  automate everyday functions.
• Weather monitoring
• Earth activities
• Manufacturing Equipment automation
• Emergency Services Search-and rescue operations
  as well as disaster recovery and medical needs.
• Patient records retrieval at point of contact
• Loss of infrastructure due to catastrophic
  disaster
• Commercial Environments electronic commerce
• Make and receive payments from anywhere
• Access customer records from the field
• Vehicular access of road conditions, weather, or
  local news
• Home and Enterprise Networking -
• Anywhere access for PDA
• Personal area networks
• Educational Applications virtual classrooms or
  conference rooms for use during conferences,
  meetings or lectures.
• Entertainment Multiuser games, robotic pets,
  and outdoor Internet access.
• Location-aware Services Follow-on services
• Call forwarding anywhere

27
Mobile Ad Hoc Networks

• Ad hoc wireless networks eliminate the
  constraints of infrastructure and enable devices
  to create and join networks on the fly any
  time, anywhere for virtually any application.

28
MANETs and MESH Networks

• Combining two point-to-point or
  point-to-multipoint MANETs begins the basic
  design of a MESH network.
• MESH networks are semi-mobile. The network nodes
  may change but the overall coverage is somewhat
  constant.
• MESH networks have dedicated routing nodes where
  every node in an MANET is a routing node.
• MANETs slowly develop into MESH networks as the
  number of nodes increases.
• MESH nodes normally are connected to every other
  node within range creating a mesh of coverage
  paths.

29
MESH Network Characteristics

• Robust network routing
• Routing addresses congestion concerns
• Routing addresses line of sight concerns
• Node density increases network throughput
• Purely dynamic mesh is not suitable for large
  scale deployment at this time.
• Development of protocols for the dynamic nature
  are still needed
• Development of protocols for address assignment
  in a mobile environment are still needed.
• MESH networks are usually designed to cover large
  geographic regions than MANETs.

30
MESH Network Example
A
B
31
Route Discovery

• (a) Range of A's broadcast.
• (b) After B and D have received A's broadcast.
• (c) After C, F, and G have received A's
  broadcast.
• (d) After E, H, and I have received A's
  broadcast.
• Shaded nodes are new recipients. Arrows show
  possible reverse routes.

32
Route Discovery (2)

• Format of a ROUTE REQUEST packet.
• When a route request arrive (B and D)
• Source address and ID is looked up no duplicate
• If route is known then Route Reply, else next
  step
• Increment hop count and rebroadcast the Route
  Request

33
Route Discovery (3)

• Format of a ROUTE REPLY packet.

34
Route Maintenance
F

• (a) D's routing table before G goes down.
• (b) The graph after G has gone down.
• Use periodic Hello

35
MANET and MESH Differences

• Logical MANET Network Logical MESH Network

36
Large Scale MESH Networks

• Large Scale deployments are possible with the
  proper design in place to provide routing nodes
  connected to wireline networks.
• Current large scale projects include research
  into Providing Metropolitan Area Network service
  across a MESH topology.

37
(No Transcript)
38
WiMAX

• Worldwide Interoperability for Microwave Access
• Telecommunications technology providing wireless
  data over long distances in a variety of ways
• FROM Point-to-Point links TO full mobile cellular
  type access

39
(No Transcript)
40
Current devices

• The list is growing every day!

41
Advantages

• Carrier Class, High-Speed, Wireless Broadband
• Lower cost that cellular
• Greater range than WiFi, Up to 3000 square miles!

42
(No Transcript)
43
Frequency

• Non line of site uses 2 Ghz to 11 Ghz. (Similar
  to WiFi)
• Line of site as high as 66 Ghz.

44
(No Transcript)
45
WiMAX Forum

• WiMAX was created by WiMAX Forum in June 2001.
• Industry-led, not-for-profit corporation
• Dedicated to certifying the interoperability of
  WiMAX Products

46
WiMAX Forum Certified

• Products and marketing materials pass conformance
  and interoperability testing
• Display certification

47
Forum WiMAX Description

• A standards-based technology enabling the
  delivery of last mile wireless broadband access
  as an alternative to cable and DSL.
• www.wimaxforum.org

48
WiMAX versus WiFi

• Long range system covering kilometers
• Similar to Cell phone
• Quality Service mechanism between Base Station
  and user device
• Highly scaleabe

• Shorter range system covering hundreds of meters
• Similar to Cordless Phone
• Quality Service mechanism similar to fixed
  Ethernet

49
(No Transcript)
50
Different Providers

• Cellular Operators
• Wireline Carriers
• Cable Operators
• MSO-multiple system operators

51
Main WiMAX Competitors

• Nortel
• Intel
• Sprint Nextel

52
WirelessMAN

• WirelessMAN is based on IEEE 802.16 standard.
• WiMAX allows user to browse internet from laptop
  computer without wall jack.

53
IEEE Standards

• Fixed WiMAX-systems built using
  802.16e-2004(802.16d) air interface technology
• Mobile WiMAX systems built using 802.16e-2005
  air interface technology

54
Key Value

• Guaranteed interoperability between networks and
  devices from multiple vendors
• A Key Value that ensures a competitive and
  dynamic industry

55
References

• http//wi-fitechnology.com/papersreq-showcontent-
  ie-7-page-2.html
• http//www.sigcomm.org/sigcomm2006/?tutorials
• http//www.commsdesign.com/showArticle.jhtmljsess
  ionid2FYCYRNWG2MY0QSNDLRCKH0CJUNN2JVN?articleID1
  60911814
• Basagni, Stefani, Conti, Marco, Giordano, Silva,
  Stojmenovic, Ivan (2004). Mobile Ad Hoc
  Networking. Wiley Sons, Inc, New Your.

56
References Cont

• www//intel.com
• www//nortel.com
• www//youtube.com
• www.apertonet.com
• http//www.wimaxforum.org/home/