Mobile Ad Hoc Network With Double Coverage Computer Science Essay

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This chapter gives an overview of mobile ad-hoc network with double coverage where the mobile Ad hoc network is the self configuration of the mobile network routers that are associated with host to connect the wireless links. Mobile Ad-hoc network is also known as MANET and it describe the network like IEEE802.11. Mobile Ad-Hoc network can also implement with the tactical radio links and in MANET each node is served both host and route. It contains the user requirement analysis that includes different types of tactical waveforms of the MANET and has to implement and test the result of the MANET.

1.2 Mobile Ad Hoc network:

According to Bulent Tavli, Wendi Heinzelman (2006), Mobile Ad Hoc network (MANET) is an independent system with the combination of nodes in mobile to connect with wireless to form network communication. The design protocol architectures of MANETs provide the Quality of Service (QoS) of certain level to transfer the information by using limited network resources like energy and bandwidth. To get the QoS requirements in real- time data communication some coordination channel are needed but coordination of centralized are not feasible in MANETs. It is dynamic, distributed entity and optimal control of such system should be adaptive and dynamic. It also provides a Time Reservation using Adaptive Control for Energy Efficiency (TRACE) of the protocol architectures in dynamic coordinated channels in distributed manner, real-time data communication in MANTEs.

According to WAN Chunfeng (n.d), Mobile ad-hoc network (MANET) is self configuring network of mobile routers and associated hosts to connect with wireless link. Network routers are free to move in sequent and organize themselves arbitrarily. The wireless network topology can change rapidly and unpredictably. The word "Ad hoc" means "for this purpose only" and implies that it is a special network to a particular application. In earlier mobile ad-hoc network (MANETs) are called "packet radio" networks. Survivable Adaptive network (SURAN) is developed by DARPA in 1983 which supports the large scale network. Ad-hoc is used to describe the kind of network by IEEE802.11 and mobile ad-hoc network is also named as MANET. Ad-hoc network used like easy to deployment, speed of deployment and decreased dependence on infrastructure and the characteristics of ad-hoc networks are decentralized, self-organized, self-deployed and dynamic network topology.

1.3 Implementing Mobile Ad Hoc Network (MANET) over Tactical Radio links:

According to MILCOM (2007), MANET is dynamic and self configuring network which consist collection of mobile nodes that are connected to wireless links. Each node in MANET has served both the host and router. The network topology and routing can be performed by the MANET nodes in a distributed fashion. The network properties of MANETs are suites of tactical network applications are infrastructure-less, self-forming and self-healing. The efforts in this area had implemented directly towards the MANET with wideband high speed data as Soldier Radio Waveform (SRW) and Wideband Networking Waveform (WNW). Implementing the MANET over legacy waveform that enables the MANET nodes with existing radios in legacy voice and data modes to provide network applications to fill the operational gap and obtain the benefits of MANET in tactical operations as range extension of voice and data in same time.

1.3.1 User Requirement Analysis:

It effectively design and implement the MANET over legacy tactical waveforms of radio that the requirements of user network that includes types of networking applications, payload characteristics, node mobility and node density. Networking Applications:

The legacy tactical waveforms has the physical layer of low bit rate. Physical layer limits the overall throughput that the network application runs over the tactical waveforms which requires low data rates. The two most effective and essential network applications are situational awareness and short payload messaging and these two requires low data rate. Situational Awareness requires transmission of location and other SA information in tactical network.SA information do not demand high data rates and has latency tolerant relatively. Tactical communication involves verb reports as position, location and tracking (PLT) to get information to other team members. SA is an ideal application for implementing MANET by using legacy tactical waveforms and two types of SA can be targeted. Short Payload Messaging is other low data rate but the tactical network applications are critical and effective. Similar to Short Message Service (SMS) to cell phones, the short payload messages are in small battlefield ad hoc network that link various teams and team members to communicate. Payload Characteristics:

It needs the tactical operations leads in some unique traffic that are characteristics as Voice/Data simultaneity, Multicasting/Broadcasting, Traffic Periodicity. In Voice/Data simultaneity the network mode can support the voice in essential to tactical radio users. Implementing the network capability over tactical radio waveforms can prevent point to point voice communication with other radio running with same waveforms. Point to point voice communicates between MANET nodes and legacy radios that voice communication supports the waveforms in non-packetized mode. In Multicasting/Broadcasting the team of tactical operations of group communication is applied and is very important to MANET tactical and Traffic Periodicity is one of the characteristic for SA traffic of the SA update messages. Periodicity can exploit when it is combined with periodical MANET control message in legacy waveform.

1.3.2 Implementation and Test results:

The feasibility and effectiveness of the mobile ad hoc network over legacy tactical radio links that implements the MANET over existing legacy tactical radio waveform which supports several tactical network applications. It describes the design choices and testing results to implement. Design Choices:

The single channel (SC) Enhanced Data Mode (EDM) to choose the physical layer of the MANET. Waveforms are chosen for some reasons as SINCGARS are widely used in tactical radio communication on the battlefield and MANET over SINCGARS supports the voice and legacy data with current deployed SINCGARS radios at same time that provide network in advance capability. The MAC layer has synchronous and asynchronous access control medium schemes that exist. The associated control packets that is not suitable to support short packets for SA and short payload messages applications. The application layer of SA and short payload message are chosen as the application which runs in MANET. The standard SA and short messaging applications of radio the embedded short messaging and SA application can also be developed that the user can send and receive the SA messages (MILCOM, 2007) . Field test results:

It performs to evaluate the performance of SA and short payload message to MANET. Test results shows all the team members of the location can trace smoothly by other team members while performing the message and chat simultaneously over the MANET(MILCOM, 2007).

1.4 Performance of TCP over routing protocol for mobile ad-hoc network:

According to MD. Abdullah-Al-Mamum, M. mahbubur Rahman and Hwee-Pink Tan (n.d), ad hoc routing protocol determine the way of route packet between devices in MANET. Nodes does not have priori knowledge of network topologies that new node announce its presence and listen the broadcast announcement from the neighbors. In this each node can aware with all other nodes and one or more ways to reach which maintain and update the route table. To keep the routing protocol effective like keep routing table up to date and reasonably, chose the best route for the given destination and converge within the exchange of small amount of message.

1.4.1 Multi-hop routing in Ad Hoc network:

If the link in MANET has occur failures, then the routing protocol is important to detect and restore the routing paths to minimize packet loss and TCP responds the packet loss by reducing window size and throughput. In this different protocols are been followed as DSR, DSDV, AODV and TORA. The Destination Source Route (DSR) has composed entirely on the on-demand mechanisms as Route Discovery and Route Maintenance. If source node wants to send the packets to the destination where the route is not available in its cache, it initiates the Route Discovery by broadcasting the route request. If route request is received the node sends the route reply to the sender that the route to the destination is available in cache otherwise it adds the address to source route in the packet header and then re-broadcast the route request.

Destination Sequence Distance Vector (DSDV) has the distance vector routing protocol that each node maintains routing table to connect the next-hop and number of hops to each destination. The sequence number is used to tag every route and the higher sequence number that indicate more update route. If node is detected then the router fails in destination as the hop numbers are set to infinity and sequence number are assigned as odd numbers.

Ad-Hoc On -demand Distance Vector routing (AODV) algorithm borrows the salient from DSR and DSDV where source needs the path to the destination that to broadcast the route request to reach the node that has the route to the destination. Every node records only the next hop for the destination but not the total route like DSR.

In Temporary Order Routing Algorithm, the node needs a route the particular destination. It broadcast the packet query to propagate it to find the node with a route to the destination or the destination itself. If the node discovers the particular destination that is unreachable then it set the corresponding local height to maximum value (MD. Abdullah-Al-Mamum, M. mahbubur Rahman and Hwee-Pink Tan).

1.5 Summary:

This chapter had covered as the mobile ad-hoc network of double coverage that contains the mobile Ad-hoc network and the implementation of the mobile ad-hoc network over tactical radio link of the user requirement analysis MANET can implement and test to supports several tactical network applications and It contain the performance TCP over routing protocol for mobile ad-hoc network which has multi-hop routing in ad-hoc network. In multi-hop routing have different protocols as DSR, DSDV, AODV and TORA. The next chapter contains the Broadcast reliability on mobile ad-hoc network.

Chapter 2: Broadcast reliability on mobile ad-hoc network

2.1 Introduction:

This chapter gives an overview of broadcast reliability on mobile ad-hoc network which is the collection of wireless mobile nodes. Broadcasting is one of the important routing in MANET for information discovery and consists of broadcast storm problem of ad hoc network. The network reliability is used to communicate with special pairs of nodes and contains the ad hoc network routing protocols and broadcasting methods in ad hoc network.

2.2 Broadcast reliability in mobile Ad-Hoc network:

According to Durga (2008), mobile Ad hoc network is collection of mobile wireless nodes which combines to form a network without any infrastructure. Broadcasting is one of the important routing in MANET for information discovery. In broadcast the process is the source node sends the message to all other nodes in MANET and the fundamental operation service in mobile ad hoc network is prone to broadcast the storm problem if forward node are not correctly designated. The process of simple broadcast algorithm is also called as double covered broadcast that takes the advantages of broadcast redundancy to improve the delivery ratio that is rather high transmission error rate. Set of selected nodes are forwarded to broadcast message. Broadcasting of all nodes in a network has an extensive application of mobile ad hoc network. The advantage of this is if one node transmits the packet all the neighbors can be received this message. Broadcasting algorithm can classify in two approaches as probabilistic approach and deterministic approach. The probabilistic approach can provide good stochastic result but has no guarantee to coverage the network. The deterministic approaches provide full coverage of network. Neighbor designating broadcast algorithm of upstream node has sent the broadcast packet that is viewed as forward node. The downstream of the forwarded node is not designated by the current node of the packet. The algorithm of Neighbor designating broadcast has divided in two approaches as static approach and dynamic approach. In multipoint relays (MPRs) selects the forwarding node to link propagates the state message.

2.3 Broadcast Storm Problem in Mobile Ad hoc Network:

According to Sze-Yao Ni, Yu-Chee Tseng, Yuh-Shyan Chen and Jang-Ping Sheu (1999), MANET consist the set of mobile hosts that can communicate with one other. The mobile host does not able to communicate directly with other host in single hop fashion; where in multi-hop the packets can send the source host by several intermediate hosts to reach the destination host. To send the broadcast messages in MANET has the problem but broadcast has common operations in many applications. It associates the broadcast storm problem to flood. These can has directions to develop the several schemes as probabilistic, counter-based, distance-based, location-based and cluster-based schemes that are facilitate in MANET broadcasting. The broadcasting storm problem has not been address in depth for MANET.

2.3.1 Broadcasting in MANET:

MANET consist a set of mobile hosts to communicate with each other on time to time and no base stations are supported. The spontaneous of the broadcast of any mobile host has some operation to issues in any time. The unreliable broadcast mechanism can be used and it should be made to distribute a broadcast message of as many hosts as available with out much effort. It assumes that the host may miss the broadcast message that it is temporarily isolated from the network and acknowledgement can cause serious contention that is surrounding by the sender and in many applications. Host can detect duplicate broadcast messages.

2.3.2 Broadcast Storm Caused by Flooding:

The straight forward approach is to perform the broadcast by flooding. In redundant rebroadcast, the mobile host decides to rebroadcast of a broadcast message of the neighbors and all its neighbors that already have the message. The contention of the broadcast message in mobile host has many of its neighbors which decide the rebroadcast the message that contend with each other. Collision has deficiency of back off mechanism that has lack of RTS/CTS dialogue in absence of CD.

2.4 Network reliability:

According to Jason L. Cook (2008), the research field can do on the network reliability analysis. Many of the research can obtain in following probabilities as the successful probability of communication between the special pairs of nodes, the entire nodes with in the network of the probability can communicate with every node by some existing paths and any terminals are connected in the probability.

The method to analyze the based reliability network for development and can extend the method of the graph theory to determine all he reliability terminals. It develops the other method to include the imperfect nodes in the existing reliability terminal algorithms and consider imperfect link for method development to perform path enumeration key to develop the approximate reliability for networks. It assign the percentage time of"arc reliability" where the researchers provides the recursive methods that removed the initial assumption of reliable nodes completely. To calculate the reliability terminal for fixed network is the method used as Boolean algebra and assumes that the nodes are completely reliable. (Liu et al, Netes and Filin, Rai, Fratta and Montanari).

2.5 Ad Hoc network routing protocols:

According to Djamel Djenouri, Abdelouahid Derhab and Nadjib Badache (2006), the routing protocols have been chosen that are based on approaches for each other. It compare in deep between the protocols that are focuses on the basic approaches.

2.5.1 Wireless Routing protocol:

It is based on the vector distance algorithm to avoid the counting of infinite problems. Wireless Routing Protocol (WRP) introduce the shortest path of the node to each destination and every node maintain tables as distance table, routing table, link cost table and Message Retransmission List (MRL). MRL must update after with each ACK reception.

2.5.2 Dynamic Source Routing:

It is a protocol reactive which is based on source route approach. The approach is that entire route is chosen by the source and puts with in each packet sent. When the packet is to be sent, first check cache, if it has a route to corresponding destination then it uses it; otherwise it launches the Route discovery by broadcasting Request (RREQ) packets by the network. If RREQ receives the node to seek the route that chases for the RREQ's destination to find such route then it send Route Reply (RREP) packet to source. If the route has not exists appropriate then add the address to the request packet and then continue the broadcasting.

2.5.3 Ad Hoc on Demand Distance Vector:

It is hop by hop routing were the node need to send data packets to the destination which has no route then it broadcast a RREQ to all the neighbors. The route between the source and destination can be developed. Like DSR source can not put the whole route with in the packet and decision about the next hop can made separately after each hop (Djamel Djenouri, Abdelouahid Derhab and Nadjib Badache (2006)).

2.6 Broadcasting methods in mobile ad hoc network:

According to N. Karthikeyan, Dr. V. Palanisamy and Dr. K. Duraiswamy (2009), broadcasting methods has divided into four families as IEEE 802.11. They are simple flooding method, probability based method, area based method and neighborhood based method.

2.6.1 Simple flooding method:

In simple flooding method, the source node of MANET sends the message to all the neighbors. Every neighbors check if they seen this message earlier, if it seen then message will be dropped, if not the message re-disseminated to all their neighbors. Simple flooding method is very reliable for MANET with low density nodes and high mobility. Blind flooding ensures the coverage as the broadcast packets are guaranteed to receive every node in the network and there is no packet loss caused by collision in MAC layer and there is no movement of high speed of nodes during broadcast process.

2.6.2 Probability based approach:

In this probability scheme is similar to flooding as except that nodes can rebroadcast with predetermined probability. In dense networks multiple nodes can be shared in similar transmission coverage, were as in sparse network there is less shared coverage. Counter based scheme shows the inverse relationship between the nodes that receives a packet in number of times and the probability of the nodes that able to reach additional area on rebroadcast.

2.6.3 Area based method:

The node receives the packet by the sender that is located in one meter away then the receiving node re-broadcast the node with additional area that is covered by retransmission. Suppose if the node is located near the boundary of the sender nodes of the transmission distance then the re-broadcast would reach the additional significant area. In this there are two schemes as Distance based scheme and location based scheme.

2.6.4 Neighbor Knowledge method:

In this self pruning is the method to reduce the broadcast redundancy. It approaches to require each node that has knowledge of its neighbors. First receiving nodes will compare its neighbor list to the sender list as the receiving node can re-broadcast the additional node that can reached other wise the receiving node can drop the message (N. Karthikeyan, Dr. V. Palanisamy and Dr. K. Duraiswamy (2009)).

2.7 Summary:

This chapter had covered as broadcast reliability on mobile ad hoc network and broadcasting is important in MANET. The broadcasting MANET consist a set of mobile hosts to communicate with each other on time to time and no base stations are supported and has broadcast Storm Problem in Mobile Ad hoc Network. It also contains the network reliability, mobile ad hoc network routing protocols and broadcasting method on mobile ad hoc networks.