1. Ad-Hoc Networks Eng. MshariAlabdulkarim

3. Advantages and Applications.

4. Cellular VS Ad-Hoc Networks.

5. Technical Challenges and Issues.

6. Ad-Hoc Wireless Media Access Protocols.

7. Ad-Hoc Routing Protocols.

10. The nodes here could be named stations or radio transmitters and receivers.MHWNs Ad-Hoc Networks Mesh Networks Wireless Sensor Networks

12. Nodes in the network are mobile in general.

13. The wireless hosts in such networks, communicate with each other without the existing of a fixed infrastructure and without a central control.

14. A mobile ad-hoc network can be connected to other fixed networks or to the Internet.

16. It is better in mobility.

17. It can be turn up and turn down in a very short time.

18. It can be more economical.

22. Fixed, pre-located cell sites and base station.

23. Static backbone network topology.

24. Relatively caring environment and stable connectivity.

25. Detailed planning before base station can be installed.

26. High setup costs.

27. Large setup time.

28. Infrastructureless networks.

29. No base station, and rapid deployment.

30. Highly dynamic network topologies.

31. Hostile environment and irregular connectivity.

32. Ad-Hoc network automatically forms and adapts to changes.

33. Cost-effective.

35. Hidden terminals.

36. Packet losses.

37. Routes changes.

38. Devices heterogeneity.

40. Unstructured and/or time-varying network topology: Because of the nodes mobility, that makes the network topology usually unstructured and makes the optimizing process a difficult task.

43. The wireless channel is weak, unreliable, and unprotected from outside interferences.

44. The wireless channel has time-varying and asymmetric propagation properties.

46. Ad-Hoc Networks Technical Challenges and Issues (6): Exposed-node problem: Blocked By The Transmitter Transmitter Exposed Node Receiver

48. If we give the node the freedom to send at any time, then that could result in a contention.

49. We can't have a central controller to manage the transmission process, because every node can move at any time.Therefore, we will choose from the medium access control (MAC) protocols in order to use the shred medium in the most efficient way.

50. Ad-Hoc Networks Ad-Hoc Wireless Media Access Protocols (2): MAC Protocols Synchronous Asynchronous MAC Protocols Sender-Initiated Receiver-Initiated

51. Ad-Hoc Networks Ad-Hoc Wireless Media Access Protocols (3): Sender-Initiated MAC Protocols: RTS 1 CTS 2 Receiver Sender Data 3

52. Ad-Hoc Networks Ad-Hoc Wireless Media Access Protocols (4): Receiver-Initiated MAC Protocols: RTR 1 Receiver Sender Data 2

54. It has the ability to control the transmitter power for each packet.

55. It uses a three-way handshake, RTS-CTS-Data.

58. In MACA-BI, there is no way that the receiver will know whether the transmitter has a data to transmit or not, which will affect the communication performance, because of the waiting time for the RTR messages.

60. It reduces the powerconsumption by turning off all nodes that are not actively transmitting or receiving.

63. In BTMA, when node is receiving data, it sends a busy tone signal to its neighbors. After the hidden terminals sense the busy tone they refrain from transmitting.

64. The DBTMA (Dual Busy Tone Multiple Access) is a customization of BTMA for the Ad-Hoc networks.

66. Ad-Hoc Networks Ad-Hoc Routing Protocols (1): There are lots of routing protocols which have been developed for Ad-Hoc networks. When these protocols have been developed, it has been taken in the consideration the limitations of this type of network. Ad-Hoc Mobile Routing Protocols Table Driven / Proactive Hybrid On-Demand-Driven / Reactive

68. In this type of routing protocol, each node should maintain at least one table to store the routing information.

70. Each node here maintains a routing table of all destinations within the non-partitioned network and the number of hops to these destinations.

71. A sequence numbering system is used in order to be able to distinguish between the old and bad routes from the new ones.

73. Destination address.

74. Number of hops to the destination.

75. Sequence number of the information received regarding the destination.

76. New sequence number unique to the broadcast.

77. Each route is labeled with a sequence number and the route with the highest sequence number will be used.

79. The WRP is classified as one of the path-finding algorithms, but here the count-to-infinity problem has been avoided by making each node check the consistency of the predecessor information reported by its neighbors.

82. Distance table: containsthe number of hops from the node to all possible destinations.

83. Routing table: specifies the next hop.

84. Link-cost table: tells about the delay for each link.

86. The update message indicates:

87. The destination.

88. The distance to the destination.

89. The predecessor of the destination.

90. List of all nodes who should acknowledge the update.

92. Each time a cluster head moves away, a new cluster head is selected.

93. By using the least cluster change (LCC) algorithm, the cluster head will be changed either if two cluster heads come into contact or if the node moves away from all other cluster heads.

96. Routing table: is used to determine the next hop to reach the destination.

98. A route discovery process is initiated by the source node.

99. This process is considered done either after:

100. finding a route to the destination.

101. after examined all the possible route permutations.

103. It can minimize the number of required broadcasts by creating routes on an on-demand basis.

105. The RREQ is identified by using the broadcast ID and the node's IP address.

106. The source node adds the last sequence number it has for the destination into the RREQ packet.

108. There are two phases in this protocol:

109. The route discovery phase.

110. The route maintenance phase.

112. Ad-Hoc Networks Ad-Hoc Routing Protocols (16): Propagation of the route replay with the route record : N1 -N2-N5-N8 N1 -N2-N5-N8 N1 -N2-N5-N8

114. This protocol performs three basic functions: route creation, route maintenance, and route erasure.

117. The logical time of link failure.

118. The unique ID of the node that defined the new reference level.

119. The reflection indicator bit.

120. The propagation ordering parameter.

121. The unique ID of the node.

123. There are two defined zones in LAR:

124. The expected zone.

127. The GPS is not yet available worldwide.

128. The positional information from the GPS could come with deviation.

130. The routing zone in ZRP is similar to the routing zone in CSGR, but in ZRP, every node acts as a cluster head and a member of other clusters, and zones can be overlapped.

131. The ZRP can be subdivided into three sub-protocols:

132. the proactive (table-driven) Intra-zone Routing Protocol (IARP).

133. the reactive Inter-zone Routing Protocol (IERP).

135. The IARP depends on the discovery protocol to detect the neighbors, and the link connectivity to them.

137. In STAR, each node maintains its own source tree.

138. Each node in STAR knows about its adjacent links and the source trees of its neighbors, and after it aggregates the adjacent links with the source trees, it will get a partial topology graph.

141. Ad-Hoc Networks Thank you for your attention