There are numerous research challenges that need to be addressed until a wide deployment of vehicular ad hoc networks (VANETs) becomes possible. One of the critical issues consists of the design of scalable routing algorithms that are robust to frequent path disruptions caused by vehicles' mobility. This paper argues the use of information on vehicles' movement information (e.g., position, direction, speed, and digital mapping of roads) to predict a possible link-breakage event prior to its occurrence. Vehicles are grouped according to their velocity vectors. This kind of grouping ensures that vehicles, belonging to the same group, are more likely to establish stable single and multihop paths as they are moving together. Setting up routes that involve only vehicles from the same group guarantees a high level of stable communication in VANETs. The scheme presented in this paper also reduces the overall traffic in highly mobile VANET networks. The frequency of flood requests is reduced by elongating the link duration of the selected paths. To prevent broadcast storms that may be intrigued during path discovery operation, another scheme is also introduced. The basic concept behind the proposed scheme is to broadcast only specific and well-defined packets, referred to as ldquobest packetsrdquo in this paper. The performance of the scheme is evaluated through computer simulations. Simulation results indicate the benefits of the proposed routing strategy in terms of increasing link duration, reducing the number of link-breakage events and increasing the end-to-end throughput.

/pdf/a-stable-routing-protocol-to-support-its-services-in-vanet-20o7agjqk5.pdf

A Stable Routing Protocol to Support ITS Services in VANET Networks

The majority of work in cognitive radio networks have focused on single-hop networks with mainly challenges at the physical and MAC layers. Recently, multi-hop secondary networks have gained attention as a promising design to leverage the full potential of cognitive radio networks. One of the main features of routing protocols in multi-hop networks is the routing metric used to select the best route for forwarding packets. In this paper, we survey the state-of-the-art routing metrics for cognitive radio networks. We start by listing the challenges that have to be addressed in designing a good routing metric for cognitive radio networks. We then provide a taxonomy of the different metrics and a survey of the way they have been used in different routing protocols. Then we present a case study to compare different classes of metrics. After that, we discuss how to combine individual routing metrics to obtain a global one. We end the paper with a discussion of the open issues in the design of future metrics for cognitive radio networks.

Routing Metrics of Cognitive Radio Networks: A Survey

Review: Survey of multipath routing protocols for mobile ad hoc networks

High-rate streaming in WSN is required for future applications to provide high-quality information of battlefield hot spots. Although recent advances have enabled large-scale WSN to be deployed supported by high-bandwidth backbone network for high-rate streaming, the WSN remains the bottleneck due to the low-rate radios used and the effects of wireless interferences. First, we propose a technique to evaluate the quality of a pathset for multipath load balancing, taking into consideration the effects of wireless interferences and that nodes may interfere beyond communication ranges. Second, we propose an interference- minimized multipath routing (I2MR) protocol that increases throughput by discovering zone-disjoint paths for load balancing, requiring minimal localization support. Third, we propose a congestion control scheme that further increases throughput by loading the paths for load balancing at the highest possible rate supportable. Finally, we validate thepath-set evaluation technique and also evaluate the I2MR protocol and congestion control scheme by comparing with AODV protocol and node-disjoint multipath routing (NDMR) protocol. Simulation results show that I2MR with congestion control achieves on average 230% and 150% gains in throughput over AODV and NDMR respectively, and consumes comparable or at most 24% more energy than AODV but up to 60% less energy than NDMR.

Interference-Minimized Multipath Routing with Congestion Control in Wireless Sensor Network for High-Rate Streaming

http://www.cs.ucy.ac.cy/ResearchLabs/netrl/papers/files/StavrouE_COMNET2010.pdf

A survey on secure multipath routing protocols in WSNs

An on-demand node-disjoint multipath routing protocol is proposed to overcome the shortcomings of on-demand unipath routing protocols like AODV and DSR. The protocol has two novel aspects compared to the other on-demand multipath protocols: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. Simulation results show that the proposed protocol achieves lower data delay and control overhead as well as higher packet delivery ratio.

On-demand node-disjoint multipath routing in wireless ad hoc networks

Mobile ad hoc networks are characterized by the use of wireless links with limited bandwidth, dynamically varying network topology and multi-hop connectivity. AODV and DSR are the two most widely studied on-demand ad hoc routing protocols. Previous work has shown some limitations of the two protocols: whenever there is a link break on the active route, each of the routing protocols has to invoke a route discovery process. This leads to an increase in both delay and control overhead as well as a decrease in packet delivery ratio. To alleviate these problems, we modify and extend AODV to include the path accumulation feature of DSR in route request/reply packets so that lower route overhead is employed to discover multiple node-disjoint routing paths. The extended AODV is called stable node-disjoint multipath routing (NDMR) protocol, which has two novel aspects compared to the other on-demand multipath protocols: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. Simulation results show that performance of NDMR is much better than that of AODV and DSR.

Stable node-disjoint multipath routing with low overhead in mobile ad hoc networks

Wireless ad hoc networks are characterized by the use of wireless links with limited bandwidth, dynamically varying network topology and multi-hop connectivity. AODV and DSR are the two most widely studied on-demand ad hoc routing protocols. Previous work has shown some limitations of the two protocols: whenever there is a link break on the active route, each of the two routing protocols has to invoke a route discovery process. This leads to increase in both delay and control overhead as well as decrease in packet delivery ratio. To alleviate these problems, we modify and extend AODV to include the path accumulation feature of DSR in route request/reply packets so that much lower route overhead is employed to discover multiple node-disjoint routing paths. The extended AODV is called Reliable Node-Disjoint Multipath Routing Protocol (NDMR), which has two novel aspects compared to the other on-demand multipath protocols: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. Simulation results show that performance of NDMR is much better than that of AODV and DSR.

A reliable node-disjoint multipath routing with low overhead in wireless ad hoc networks

Mobile ad hoc networks are characterized by the use of wireless links with limited bandwidth, dynamically varying network topology and multi-hop connectivity. AODV and DSR are the two most widely studied on-demand ad hoc routing protocols. Previous work has shown some limitations of the two protocols: whenever there is a link break on the active route, each of the two routing protocols has to invoke a route discovery process. This leads to increase in both delay and control overhead as well as decrease in packet delivery ratio. To alleviate these problems, we modify and extend AODV to include the path accumulation feature of DSR in route request/reply packets so that lower route overhead is employed to discover multiple node-disjoint routing paths. The extended AODV is called Node-Disjointness-Based Multipath Routing Protocol (NDMR), which has two novel aspects compared to the other on-demand multipath protocols: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. Simulation results show that performance of NDMR is much better than that of AODV and DSR.

Node-disjointness-based multipath routing for mobile ad hoc networks

Future mobile ad hoc networks (MANETs) are expected to be based on all-IP architecture and be capable of carrying multitudinous real-time multimedia applications such as voice, video and data. It is very necessary for MANETs to have a reliable and efficient routing and quality of service (QoS) mechanism to support diverse applications which have varying and stringent requirements for delay, jitter, bandwidth, packets loss. Providing multipath routing is beneficial to avoid traffic congestion and break in communication in MANETs where routes are disconnected frequently due to mobility. Differentiated Services (DiffServ) which have simple, efficient and scalable characteristics can be used to classify network traffic into different priority levels and apply different scheduling and queuing mechanisms to obtain QoS guarantees. In this paper, we propose a practical node-disjoint multipath QoS routing protocol of supporting DiffServ (MQRD), which provides low routing overhead and end-to-end QoS support. Simulation results show that MQRD achieves better performance in terms of packet delivery ratio and average delay.

Xuefei Li

Papers

On-demand node-disjoint multipath routing in wireless ad hoc networks

Stable node-disjoint multipath routing with low overhead in mobile ad hoc networks

A reliable node-disjoint multipath routing with low overhead in wireless ad hoc networks

Node-disjointness-based multipath routing for mobile ad hoc networks

Multipath QoS routing of supporting DiffServ in mobile ad hoc networks