97 Chapter 7 CONCLUSION 7.1. Introduction A Mobile Ad-hoc Network (MANET) could be considered as network of mobile nodes which communicate with each other without any fixed infrastructure. The nodes in a MANET would move freely in any direction and hence, they would change their links to other nodes as they move. Each node must also act as a router forwarding the traffic. Thus each node must be equipped in such a manner that they route the traffic properly. These networks either operate on their own or they may also be connected to the larger internet. The objective of a multicast routing protocol for MANET is to support the propagation of data from a sender to all the receivers of a multicast group while trying to use the available bandwidth efficiently in the midst of frequent topology changes. Though multicasting can improve the efficiency of the wireless link by exploiting the inherent broadcast property of wireless transmission, it is extremely difficult in MANET due to its limited resource of bandwidth. Another important issue to be considered is the limited battery power, Routing protocols in MANET, establish the path between the source and the destination based on the number of hops. Establishment of the shortest path alone is not sufficient to prolong the network life time. Energy consumption reduction techniques are necessary as the nodes in MANET are limited by battery supply. Energy is drained when the MANET nodes transmit and receive the data. Energy
98 consumption in MANET also depends on the residual battery capacity, distance between the nodes, retransmission and overhearing. As such, energy management techniques are necessary in order to improve the performance of the multicast routing protocol.further, QoS support in MANET is a challenging task due to the dynamic nature of Mobile Ad hoc Networks. The resources must be assigned or reserved in order to achieve a desired QoS. The constraints of MANET, namely, bandwidth, dynamic topology, limited processing and storing capabilities of devices must be concentrated to support QoS in MANET. QoS in MANET can be achieved by the QoS model, QoS signaling and QoS routing. We have specifically investigated and achieved QoS routing utilizing the MAODV protocol. 7.2. Research Issues addressed Taking the above issues into consideration, our thesis have addressed the following energy and QoS related challenges in multicast routing protocol for MANET. 5. Energy Drain Reduction using Multicast Routing Protocol 6. Improved Energy Efficiency using Distributed Swarm Intelligence (DSI) in Wireless Mobile Networks 7. Design and Implementation of a Novel Energy Efficient Multicast Routing Protocol for MANET 8. QoS enabled MAODV for Mobile Ad hoc Networks 7.3. Energy Drain Reduction using Multicast Routing Protocol (EDR-MRP)
99 Chapter 3 discussed the proposed Energy Drain Reduction using Multicast Routing protocol(edr-mrp).energy management techniques are necessary to improve the performance of the routing protocol. The proposed multicast routing protocol EDR-MRP addresses the issues of energy drain to establish the path. The energy drain may occur due to the transmission and reception of control and data packets. The protocol also concentrates the residual battery capacity and the distance between the nodes to manage the energy consumption. Chapter 3 which discusses the proposed EDR-MRP protocol establishes the energy efficient path in the multicast routing protocol MAODV, by managing the energy drain in the transmission and reception of data. 7.3.1. Simulation Results The proposed protocol is simulated and evaluated using ns-2.it is compared with the MAODV to analyze the performance. 60 nodes were simulated in an area of 1000m 1000m.The simulation duration is of 1000s.The mobility model is the random way point mobility model and the MAC protocol used is IEEE 802.11.The initial energy of the node is 1000 joules and the channel capacity is 2Mbps. The metrics packet delivery ratio, throughput and energy consumption are used to analyze the performance of the protocol. 7.3.1.1. Packet Delivery Ratio The results show that the Packet delivery ratio of the proposed EDR-MRP is significantly increased when compared with MAODV. The increase is due to the selection of the path which needs minimum energy to transmit the data which in turn reduces the number of control packets to find out the neighbor, if any of the nodes are dead due to the scarcity of power. This result is shown in Table 1.
Table:7.1. Comparisons of PDR vs. Number of Receivers of MAODV and EDR-MRP 100 S.NO Receivers MAODV EDR-MRP 1 10 0.953 0.960 2 20 0.799 0.979 3 30 0.86 0.949 4 40 0.79 0.932 5 50 0.62 0.923 7.3.1.2. Energy Consumed Table:2 shows the energy consumed by the node after the occurrence of the transmission and reception of the data. The initial energy of the node is 0.277 watts. Energy consumed by EDR-MRP is less when compared to MAODV. This is due to the selection of the minimum energy path based on the metric link quality, received signal strength and the distance between the nodes. But MAODV transmit and receive the packet with the default maximum energy of 0.277 watts irrespective of the distance, link quality and hence consumes more energy. The energy consumption of MAODV is 0.003 watts to 0.007 watts more when compared to EDR-MRP.
Table: 7.2. Comparison of energy consumed for MAODV and EDR-MRP 101 S.No Receivers MAODV (watts) EDR-MRP(watts) 1 10 0.006 0.003 2 20 0.007 0.003 3 30 0.011 0.007 4 40 0.013 0.006 5 50 0.015 0.008 7.3.1.3. Throughput Table: 3 show the increase in the throughput of EDR-MRP against the number of receivers. The path which needs minimum energy is chosen to transmit and receive the data. Hence the life-time of the nodes may be increased and hence reduce the control overhead which leads to increase in the throughput. Table: 7.3. Comparison of Throughput for MAODV and EDR-MRP S.No Receivers MAODV (kbps) EDR-MRP (kbps) 1 10 134 149 2 20 222 253 3 30 359 400 4 40 445 547
102 7.3.2. Conclusion Thus the proposed EDR-MRP protocol gives improved results in terms of Packet Delivery ratio and throughput over MAODV. The energy consumption is reduced by.007 watts compared to MAODV, if the number of receivers is 50 with the senders as 10. EDR-MRP may be useful for any applications of Wireless Ad Hoc Networks. 7.4. Improved Energy Efficiency using Distributed Swarm Intelligence (DSI) in Wireless Mobile Networks 7.4.1. Introduction The next chapter proposed a novel Mobile Ant Based Routing (MABR) with Distributed Swarm Intelligence (DSI) algorithm in order to improve the energy efficiency. Distributed path computation remains a core functionality of modern communication networks Link-state and Distance vector algorithms are used widely. In both methods, nodes choose successor (next-hop) nodes for each destination based only on local information. This chapter proposes an additional algorithm i.e. Mobile Ants-Based Routing (MABR) with DSI to chosen better paths to the destination in an appropriate manner. The distribution computation is carried out using Ant Colony optimization with DSI and this novel approach shows the performance improvement of their QoS metrics based on the parameters viz. Delay, Data rate, Packets Received and Packets Lost. We are able to achieve consistency across nodes further aiding energy Efficiency using Distributed Swarm Intelligence (DSI) in Wireless Mobile Networks.
7.4.2. Conclusion 103 The proposed MABR with DSI algorithm gives improved results in terms of reduced packet loss and thereby improving the QoS. Results also show that our novel algorithm achieves energy efficiency through reduced energy consumption and the delay is greatly reduced by almost 50%.Thus, the proposed MABR with DSI algorithm improves energy efficiency. 7.5. Design and Implementation of a Novel Energy Efficient Multicast Routing Protocol for MANET Chapter 5 proposed a novel Energy Efficient Multicast Routing protocol for MANET. MANET uses multicast communication, suitable for an intrinsic broadcast capability with a shared-tree architecture that maintains a group membership, where the group includes a group leader and group member. Existing methodologies have more complexities like link breakage, energy loss due to low battery and bandwidth loss. Here, we propose a new mechanism to reduce all the above stated disadvantages by using a novel energy efficient multicast routing protocol which has lesser control overhead. This technique is suitable for MANET. A Shared Multicast tree is constructed for multicast nodes which reduces the overhead of the network. The routes are discovered in the MANET by locating the physical location of nodes that are present in the network using the route searching strategies and thereby reducing energy consumption. Apart from this technique, we also introduce a new Zone topology concept to differentiate the nodes based on minimum and maximum hops. In order to overcome link failure in MANET, a back-up node is maintained near the source node which contains all the details of the source node. In the event of failure of
104 source node, backup node sends the failure information to all nodes in the network. The network nodes are monitored in certain time interval to reduce the link failures that happen due to loss of energy in nodes, a node that has a lower energy will consume the energy i.e. it share its energy with its neighbor node instead of making a sub-path and the data are sent in an compressed form from a source to destination reduce the time in reaching its destination. 7.5.1. Novel Energy Efficient Approach The main objective is to minimize the energy utilization in mobile network. The aim of this algorithm is to provide a solution which would improve energy efficiency, speedy packet delivery and prevent link breakages. In the mobile network all the nodes will be dispersed. Each node should be aware of the neighbor nodes and all the energy levels of the neighbors so as to select the appropriate neighbor with the substantial energy to forward and receive the packets. All the node information are managed in location table and score card table. Thus appropriate selection of the effective nearby node is performed without spending much energy. Further, a well known Location Aided Routing is used to locate the node to proceed packet forwarding.
105 7.5.2. Result and Discussion The picture 2(a) below depicts the zone building step of our proposed approach Figure: 2(a) Zone building Figure.2 (b) Establishment of multicast path between Node 7 and Node 16 In Figure 2(b), we have shown both the multicast path and the transmission. The transmission paths are identified in black lines. The Node no 28 is the selected backup node due to its high power. The figures below indicate the speed and delay estimation, group size and delay estimation, mobility speed and control overhead and packet delivery ratio metrics which prove that our algorithm is better than conventional MANET Routing Protocols.
106 Figure.3 a Performance Evaluation of Mobility Speed and Delay Estimation in MANET Figure.3 (a) shows the Mobility Speed is improved and Delay is reduced using our algorithm when compared with other related algorithms. Figure.3 (b) Performance Evaluation of Mobility Speed &Control Overhead packet Estimation in MANET
107 Figure.3 (b) shows the Mobility Speed is improved and the Control Overhead packet Estimation in MANET is reduced using our algorithm when compared with other related algorithms. Figure.3(c) Performance Evaluation of the Number of Nodes & Packet Delivery ratio Estimation in MANET Figure.3 (c) shows the Number of Nodes and Packet Delivery ratio Estimation in MANET is reduced using our algorithm when compared with other related algorithms. 7.5.3. Conclusion Our novel energy efficient approach could be suitably used to control the network overheads and to minimize the energy utilization in the MANET. This novel approach also guarantees the elimination of the drawbacks like loss of energy due to less battery power etc. Our algorithm also ensures good reduction in latency during the splitting of the network as well as eases the node location process. It has a shared tree structure to avoid the congestion in the source node and it continues its execution through a backup root node in case of failures. Thus the
108 energy is balanced in each point of communication by sharing the energy during node failures. 7.6. QoS enabled MAODV for Mobile Ad hoc Networks Chapter 6 presents a QoS enabled MAODV for Mobile Ad hoc Networks.QoS support in MANETS is a challenging task due to the dynamic nature of Mobile Ad hoc Networks. In order to achieve a desired QoS, the resources must be assigned or reserved. MANET constraints such as bandwidth, dynamic topology, limited processing and storing capabilities of devices must be concentrated to support QoS in MANET. QoS in MANET can be achieved by the QoS model. QoS signaling and QoS routing. In this chapter, QoS routing is achieved utilizing the protocol MAODV. QoS routing searches for a feasible path between the source and the destination which satisfies the QoS requirements and optimize the use of network resources. 7.6.1. QoS Multicast Ad Hoc On-Demand Distance Vector Routing Protocol The objective of the proposed protocol Q-MAODV is to find the feasible path which satisfies the QoS constraints delay, hop count and bandwidth. Q-MAODV model the network as weighted graph G (N, E) in which N represents the numbers of nodes and E the set of links or edges connecting the nodes. Let S denote the source and D denotes the destination among N nodes. Q-MAODV aims to find the links that meet the QoS requirements between the source and the destination. 7.6.2. Simulation Results Simulation of M-MAODV is performed and compared with MAODV using NS-2 to evaluate the protocol. A total of 60 nodes were simulated for duration of 1000s
109 in an area of 1000m * 1000m. The mobility model is the random way point (Lin et al 2004) to model the mobility of the nodes in the network. The MAC layer protocol used was IEEE 802.11. The transmission range for each node was 250m and the channel capacity was 2 Mbps. The size of the packet was 512 bytes. The metrics of Packet delivery ratio, End-to-end delay and Throughput were evaluated for all the protocols developed. 7.6.2.1. PDR vs. Number of Receivers Table 7.4. shows the packet delivery ratio (PDR) against the variation in the number of receivers. Less number of control packets are utilized to establish the path, since the source node selects the RREP only if the qos constraints are satisfied. Hence from the Table 7.4, it is inferred that the PDR of Q-MAODV is increased compared to MAODV. The increase of the PDR values ranges from 0.02 to 0.10. Table 7.4. Comparison of PDR vs. Number of Receivers of MAODV and Q-MAODV S.No Receivers MAODV Q-MAODV 1 10 0.953 0.9 2 20 0.799 0.89 3 35 0.86 0.88 4 40 0.79 0.84 5 50 0.62 0.78
7.6.2.2. Throughput 110 Table 7.5 show the throughput of the protocol evaluated against the variation in the number of receivers. The path which satisfies the QoS constraint delay and bandwidth is selected to transmit the data. Hence, the throughput of Q-MAODV has been increased from 6 kbps to 33 kbps when compared with MAODV. Table 7.5. Comparison of Throughput of MAODV and Q-MAODV S.No Receivers MAODV (kbps) Q-MAODV (kbps) 1 10 134 140 2 20 222 236 3 30 359 365 4 40 445 478 7.6.2.3. Delay Table 7.6 show the delay evaluated against the variation in the number of receivers with the senders as 10. The delays include all the delays that are occurred by buffering during route discovery latency, queuing at the interface queue, retransmission delays at the MAC and the time taken to propagate and transfer. The delay of Q-MAODV is reduced by 1 to 3 milliseconds when compared with MAODV.
111 Table 7.6. Comparison of Delay for MAODV and Q-MAODV S.No Receivers MAODV (millisec) Q-MAODV (millisec) 1 10 14 13 2 20 17 14 3 35 17 14 4 40 18 17 5 50 20 19 7.6.3. Conclusion Q-MAODV established a route to the destination satisfying the QoS constraints delay, and bandwidth. The QoS constraints are used to optimize the path. Depending on the application, the application requirements could be transformed to QoS requirements. The performance is enhanced compared to the protocol MAODV. PDR and throughput is significantly increased. Delay is also reduced which is due to the selection of the path that satisfies the QoS requirements.
112 Thus, this thesis focused on the issues of energy efficiency in multicast routing protocols for MANETs and successfully addressed the following challenges, namely, 1. Energy Drain Reduction using Multicast Routing Protocol 2. Improved Energy Efficiency using Distributed Swarm Intelligence (DSI) in Wireless Mobile Networks 3. Design and Implementation of a Novel Energy Efficient Multicast Routing Protocol for MANET 4. QoS enabled MAODV for Mobile Ad hoc Networks. 7.7. Future Work In the future, the above proposed protocols could be extended to analyze the QoS metrics in an distributed network with increased number of nodes. Further, additional QoS metrics could be analyzed based on the proposed protocols and results could be observed for further improvement of the protocols.