Routing Protocols for Ad-hoc Wireless Network Dissertation

Routing Protocols for Ad-hoc Wireless Network - Dissertation Example IEEE 802.11g standard is also operational on a 2.4 GHz unlicensed frequency spectrum that offers a maximum Mbps rate of data by using Orthogonal Division Multiplexing in the frequency band. Chapter 3: Routing Protocols for Ad-hoc Wireless Network 3.1. Routing Protocols As stated previously in this paper, an ad-hoc mobile network refers to a number of wireless mobile hosts linked together to form a network of temporary nature without using any centralized control or stand-alone infrastructure [18]. MANETs are not multi-hop wireless networks that are only self-configuring but also self-organizing, in which the network structure changes dynamically, primarily, because of the portability of the nodes [22]. Such networks have their nodes use the uniform random access wireless channel in order to get involved in multi-hop broadcasting by cooperating with each other in a friendly manner. These nodes serve as both hosts as well as routers routing data to and from other nodes within MANET [21 ]. Since the MANETs have no support of the infrastructure as opposed to the other wireless networks and there is a possibility of a destination node not being found within the range of the source-node-network of the forwarding packets, hence a mechanism for routing is compulsorily required for determining a path in order to transmit the packets properly from the node of the source to the node of the destination. Commonly, a base station in mobile network within a cell can access all the wireless nodes without the mechanism of routing through the broadcasting method whereas in the MANETs, each node should be transmitting the data on behalf of the other nodes. This gives rise to other issues besides the issue of unpredictable connectivity changes related to dynamic topology (Schiller, 2000). 3.2. Issues with Routing in MANETs Asymmetric links: Many wired networks are based on the fixed symmetric links as opposed to the MANETs where the nodes are wireless and also, dynamic as they keep changing their network position. As for instance, consider a MANET having a node B transmitting a signal towards node A. This information tells nothing in relation to the quality or level of the connection in the reverse order that is sending signal back to node B from node A (Schiller, 2000). Overhead in the Routing Mechanism: The nodes, in a MANET, are dynamic with respect to their network location as mentioned above. Hence, a number of invalid paths are produced in the routing table accounting for excessive overhead. Interference: Interference is a big issue in MANETs since the links are made and broken on the basis of the transmission properties, subsequent to which one transmission might intervene or intrude in another line of transmission causing the corresponding node to tap the communication of the nodes in other transmission lines and thereby, falsify the overall system of transmission. Dynamic Network Topology: This is another issue of great concern in MANET routing as th e topology keeps on changing. The nodes of the MANET are dynamic since the change their network location and also, the medium has the changing/dynamic properties. The routing tables, in the MANETS, must be able to indicate such changes taking place in the network topology by adapting the appropriate routing algorithms. As for instance, the routing table is updated in every 30 seconds in a fixed network (Schiller, 2000). On the other hand, the updating frequency for the ad-hoc networks might be very low. 3.3. Various Network Protocols in MANET’s and their Comparisons Although the network protocols in MANETS can be classified in numerous ways however many of these are performed on the basis of both the routing mechanism and the network structure [20]. In accordance to the routing mecha