Elsevier

Ad Hoc Networks

Volume 10, Issue 7, September 2012, Pages 1399-1418
Ad Hoc Networks

A virtual multiple message ferry backbone routing scheme for mobile ad-hoc networks

https://doi.org/10.1016/j.adhoc.2012.03.018Get rights and content

Abstract

A MANET (Mobile Ad-Hoc Network) consists of relocating wireless communication devices without infrastructure installed in its network environment. Due to the mobility of the devices, the network topology changes frequently and consequently results in poor network performance. When the density of nodes in a MANET is sparse, the performance becomes even worse due to the intermittent connected routing problem arising. To cope with this problem, this paper integrates mechanisms of Virtual Multiple Message Ferry Routing (VMMFR) and Virtual Multiple Message Ferry Dispatch Scheduling (VMMFDS) into the routing protocol design of MANETs and proposes a Virtual Multiple Message Ferry Backbone Routing (VMMFBR) scheme for MANETs. Several simulations have been conducted using the network simulator NS-2 to evaluate the performance of the proposed VMMFR mechanism. Due to the VMMFR mechanism providing a reliable and predictable backbone routing for MANETs communications. The results show that the proposed method has a higher packet delivery ratio, low bandwidth consumed, and that there is greater precision of packet delivery time, compared to the traditional MANETs routing protocols (AOMDV and DSR). In addition, some theoretical results for the proposed VMMFDS mechanism to minimize the transfer waiting time are also given in this paper.

Introduction

Since the release of the IEEE802.11 standard in 1997 [1], a great number of novel applications of wireless networks have been developed for enhancing the quality of our daily life. It has given fresh impetus to increase the number of Internet users and also to promote the development trend of wireless network applications. Traditional applications, such as information retrieval, instant messaging, and multimedia on demand, can now be easily achieved for users through wireless devices (e.g., laptop computers, smart phones, or even car PCs) without the limitation of being wired. Wireless networks can be classified into two categories: infrastructured and infrastructureless. The communications between nodes in infrastructured wireless networks are two-hop communication via a pre-deployed access point; that is, the source node firstly sends the message to the access point, and then the access point relays it to the destination. For the infrastructureless wireless networks (also known as ad hoc networks), the access point is no longer required; instead, the nodes within the network environment can self-organize themselves to form the network. Each node plays the role of a router, and the communications between two nodes can use a multihop fashion via the aid of other nodes.

Since the nodes in ad hoc networks are capable of moving, these networks are called Mobile Ad-Hoc Networks (MANETs) [2], [3]. Due to the MANETs having fine characteristics such as no longer requiring a centralized coordinator (the access point), node mobility, self-organization and ease of deployment, many helpful applications for MANETs have been proposed for diverse environments, such as disaster rescue, communications on battlefields, and communications between cars on the road. Thus MANETs have received much attention from researchers. However, the mobility and the limited transmission range of nodes in MANETs will lead to the network links being frequently broken and consequently the network topology often changes. The maintenance of routing paths in MANETs thus becomes difficult. Moreover, the situation will become worse when the node density is sparse in the network environment. Therefore, the routing design for MANETs is a challenging task in terms of ensuring stable routing to increase the successful transmission rate.

Traditional routing protocols using a pro-active approach; i.e., constantly maintaining routing tables, are no longer appropriate in such an environment. Instead, the re-active approach that starts to discover a routing path only when it is needed, is more suitable in a MANET environment. This approach conserves a considerable amount of network bandwidth compared to the pro-active approach. The Dynamic Source Routing (DSR) [4] is known as a re-active routing protocol for MANETs.

The other approach to deal with the problem of the topology frequently changing is to use multipath routing [5], [6], [7], [8], [9]. The routing protocols belonging to this approach will find several routing paths between the source and destination in advance. In case of the current routing path for message transmission being broken, the routing protocol will quickly switch to the other existing path and then continue message transmission. The Ad hoc On-demand Multipath Distance Vector Protocol (AOMDV) [5] is one of the well-known multipath routing protocols.

The above approaches which deal with the problem caused by node mobility are satisfactory when the density of nodes is high and the relative speeds of the nodes are low. In contrary conditions, the more serious problem of the topology connecting and disconnecting interchangeably, called an Intermittent Connected Routing Problem will arise. Consequently, the routing design for such a circumstance will become more difficult. In the following, we will use Fig. 1 as an example to illustrate the problem. As shown in Fig. 1, mobile nodes are roaming in a rectangular area. The dashed circle with respect to each node represents its transmission range. Firstly, at time t = 0, node S transmits a message to node D along path SACD. But the path broke at time t = i due to node A moving away from S and causing link (S, A) to break, where i  R+ denotes the time that the path broken event occurred. The route repair mechanism of traditional routing protocols can quickly find an alternate route, say SBECD to replace the broken one and take the responsibility for message transmitting (see Fig. 1c). At time t = i + ϵ + j (i, ϵ, j  R+), the route again broke. However, this time the routing protocol can no longer find an alternate route, since the network becomes disconnected. It is not until time t = i + ϵ + j + k (i, ϵ, j, k  R+) that the network becomes connected again. The above situation (the status of the network being connected and disconnected interchangeably) may occur several times during a transmission. During the period of the network being disconnected, the traditional routing protocols will be busy performing the route repair process which consequently wastes a great deal of network bandwidth. The computer networks with this Intermittent Connected Routing Problem are called Delay Tolerant Networks (DTNs) [10], [11]. There are several proposed routing protocols to deal with this problem [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23]. Among this research, the flooding approach is the easiest way to cope with the problem. However, it will cause a broadcast storm disaster and the buffer of each node will quickly become full of redundant packets.

Epidemic routing [12] is another approach to relieve the heavy burden on network bandwidth usage due to the flooding approach. In this routing scheme, whenever a node, say node A, encounters another node, say node B, then they will perform an anti-entropy process with each other. The anti-entropy process is that, firstly, node A will send a summary vector SVA to node B, which briefly describes the carrying messages of node A. As soon as node B receives the SVA, it will compare its carrying messages with this vector to determine the messages that node B lacks but node A owns. At last, node B will send a message to notify node A to send them to node B. Similarly, node B will perform the same anti-entropy process with node A. After the two anti-entropy processes have been successfully performed, both nodes A and B will carry the messages of the union of two nodes’ carrying message sets. By repeating such an epidemic approach, messages will eventually arrive at their destinations. Though the epidemic routing approach can relieve the broadcast storm problem raised by flooding, the number of replicated messages is still large and the message relaying relies heavily on the stochastic behaviors of the nodes which encounters each other, but which are not deterministic.

Message Ferry Routing [14], [15], [16], [17], [18], [19], [20], [21], [22], [23] provides a useful approach to avoid the stochastic and uncertainty drawbacks of the epidemic approach. Generally, the Message Ferries (MFs) are some sort of special nodes roaming along a predetermined trajectory and are also known by other nodes in MANETs. For example, buses on the road. Through the aids of MFs, the message transmitting performance in MANETs can be enhanced. A detailed description of the routing mechanism will be presented in the next section. Since the nodes being chosen to play the role of MFs will violate their original moving behavior, most of the nodes in the network do not adequately play such roles, except some special type of nodes (such as buses). On the other hand, though the buses move along a predetermined route, the time precision for the MFs shown at any position while traveling on the trajectory are not accurate. Thus, applying the traditional Message Ferry Routing Scheme in a MANET environment is not practical.

In this paper, we propose a Virtual Multiple Message Ferry Routing (VMMFR) scheme to relieve the above problem of the MF approach. In our proposed approach, the role of the Virtual Message Ferries (VMFs) can be played by any node in a MANET, without violating its original moving direction. In addition, we consider a Virtual Multiple Message Ferry Dispatch Scheduling (VMMFDS) optimization problem for finding a VMF’s dispatch time scheduled to minimize the total transfer waiting time while relaying messages over the multiple message ferry routes. By synthesizing the above two mechanisms, a complete and more practical routing scheme, the Virtual Multiple Message Ferry Backbone Routing (VMMFBR) for MANETs is proposed. The organization of this paper is as follows. A description of related MF research is given in Section 2. In Section 3, the proposed VMMFR and VMMFDS are described. The simulation results and some theoretical results of the proposed methods, and the concluding remarks are given in Sections 4 Simulation results, 5 Conclusion, respectively.

Section snippets

Related message ferry routing works

The main benefits of the MF approach are twofold: (1) the MFs can establish connections between the connected components of a disconnected network; (2) since the trajectories of MFs are predetermined, the positions of MFs at any given time can then be predicted, which can help the packet forwarding decision of nodes. Generally, the MF trajectories designed by the network designer aims to cover the entire MANET environment [16], [17], [22]. The total delay time (or transfer waiting time) between

The proposed routing method

In this paper, a Virtual Multiple Message Ferry Backbone Routing (VMMFBR) scheme is proposed for relieving the above drawbacks. In the VMMFBR scheme, any node in the MANET is possible as a Virtual Message Ferry (VMF) to assist message carrying and relaying at any time period. Later it will no longer be a VMF but will change back to a normal node. The VMMFBR is a two-tiered hierarchical architecture. The upper-tier takes the responsibility for the trajectory planning of VMFs to form a backbone

Simulation results

In order to evaluate the performance of our proposed VMFs routing scheme, some experiments using the network simulator NS-2.34 [25] were performed to compare the proposed method with some traditional MANET routing algorithms, which include DSR and AOMDV. The compared performance metrics include the packet delivery ratio, the node bandwidth utilization, and the packet arrival time error rate of the time that a packet is received by destination against the arrival time that is preplanned for the

Conclusion

In this paper, we have proposed an integrated mechanism of VMMFR (Virtual Multiple Message Ferry Routing) and VMMFDS (Virtual Multiple Message Ferry Dispatch Scheduling) into the routing protocol design of MANETs and have proposed a VMMFBR (Virtual Multiple Message Ferry Backbone Routing) scheme. We have also proposed a network optimization problem for the VMMFDS to arrange the time table of each VMFs dispatch scheduling such that the total ferry transfer waiting time will be minimized while

Acknowledgment

The author would like to thank Chien-Hung Liu for his helpful assistance in obtaining the simulation results.

Chu-Fu Wang received the B.S. degree in Applied Mathematics from National Cheng Kong University, and the M.S. and Ph.D. degrees in Computer and Information Science from National Chiao Tung University, Taiwan, in 1993, 1995, and 2001, respectively. He joined the Department of Computer Science, National Pingtung University of Education, in 2002, where he is currently an Associate Professor. His research interests include multicast distribution, mobile computing, and network optimization.

References (25)

  • S. Adibi, S. Erfani, A multipath routing survery for mobile ad-hoc networks, in: Proceeding of the IEEE Consumer...
  • N.Z. Ali, R.B. Ahmad, S.A. Aljunid, A survey on on-demand multipath routing protocol in MANETs, in: Proceeding of the...
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    Chu-Fu Wang received the B.S. degree in Applied Mathematics from National Cheng Kong University, and the M.S. and Ph.D. degrees in Computer and Information Science from National Chiao Tung University, Taiwan, in 1993, 1995, and 2001, respectively. He joined the Department of Computer Science, National Pingtung University of Education, in 2002, where he is currently an Associate Professor. His research interests include multicast distribution, mobile computing, and network optimization.

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