Dong-Won Kum

Performance Evaluation of AODV and DYMO Routing Protocols in MANET

Routing protocols for mobile ad hoc networks (MANETs) have been explored extensively in recent years. Among these routing protocols, Ad Hoc On-demand Distance Vector (AODV) and Dynamic Manet On-demand (DYMO) routing protocols have been standardized by the IETF MANET WG and are the most popular reactive routing protocols for MANETs. Therefore, in this paper, we present the results of the comparison of two reactive routing protocols, namely AODV and DYMO, based on packet-level simulations using an ns-2 simulator. Simulations are run to estimate the total throughput, routing overhead, and average packet size of the routing control packets.

Seamless Handover Scheme for Proxy Mobile IPv6

In a network-based approach such as proxy mobile IPv6 (PMIPv6), the serving network controls mobility management on behalf of the mobile node (MN). Thus, the MN is not required to participate in any mobility-related signaling. PMIPv6 is being standardized in the IETF NetLMM WG. However, the PMIPv6 still suffers from a lengthy handover latency and packet loss during a handover. In this paper, we propose a seamless handover scheme for PMIPv6. The proposed handover scheme uses the Neighbor Discovery message of IPv6 to reduce the handover latency and packet buffering at the Mobile Access Gateway (MAG) to avoid the on-the-fly packet loss during a handover. In addition, it uses an additional packet buffering at the Local Mobility Anchor (LMA) to solve the packet ordering problem. Simulation results demonstrate that the proposed scheme could avoid the on-the-fly packet loss and ensure the packet sequence.

An efficient on-demand routing approach with directional flooding for wireless mesh networks

Current on-demand ad-hoc routing protocols are not appropriate for wireless mesh networks (WMNs), because flooding-based route discovery is both redundant and expensive in terms of control message overhead. In this paper, we propose an efficient on-demand routing approach with directional flooding (DF), which is suitable for the WMNs with limited mobility. In the route discovery process to reach a gateway, our DF scheme can reduce the number of route request (RREQ) packets broadcast by using a restricted directional flooding technique. Simulation results show that ad hoc on-demand distance vector (AODV) with DF (AODV-DF) can significantly reduce routing overhead by RREQ packets and enhance overall performance compared with the original AODV.

Directional AODV Routing Protocol for Wireless Mesh Networks

In most application scenarios, Wireless Mesh Networks (WMNs) are stationary or quasi-stationary with support of minimal mobility, in which most of their traffic is destined to the Internet through a gateway. Ad hoc On-demand Distance Vector (AODV) is not appropriate for such WMNs, because flooding-based route discovery is both redundant and very expensive in terms of control message overhead. In this paper, we propose a directional AODV (D-AODV) routing protocol based on hop count to a gateway. In the route discovery to a gateway, D-AODV can reduce the number of broadcasting route request (RREQ) packets by using a restricted directional flooding technique. Simulation results showed that D-AODV could significantly reduce routing overhead by RREQ packets and enhance overall throughput performance.

An Efficient Hybrid Routing Approach for Hybrid Wireless Mesh Networks

A hybrid mesh network is the most generic type of Wireless Mesh Networks (WMN) and is a combination of static mesh routers and mobile mesh clients. Static mesh routers are typically much less resource-constrained than mobile mesh clients, and are also often equipped with multiple radio interfaces. Furthermore, most of the traffic is directed to/from a gateway, as the mesh clients generally access services on the Internet or other networks. Thus, routing protocols need to distinguish the types of mesh node and take account of the traffic pattern in hybrid mesh networks. This paper proposes a Hybrid Distance Vector (HDV) routing protocol for hybrid mesh networks, which combines the tree-based routing strategy with the reactive routing strategy. Simulation results demonstrate that the proposed HDV routing protocol can outperform AODV and AODV-ST routing protocols in terms of the routing overhead, network throughput, and end-to-end delay in a hybrid mesh network.

Global Mobility Management Scheme with Interworking between PMIPv6 and MIPv6

The network-based mobility management scheme, proxy mobile IPv6 (PMIPv6), was recently proposed by the IETF NetLMM WG. In a PMIPv6 domain, an mobile node (MN) mobility can be provided without any mobility protocol stack, such as Mobile IPv6 (MIPv6). However, since the PMIPv6 protocol was only designed for local mobility management, MN mobility cannot be supported outside a PMIPv6 domain. Accordingly, to support global mobility management, we propose an interworking scheme between PMIPv6 and MIPv6, including integrated functional architecture between local mobility anchor function (LMAF) and home agent function (HAF), explicit HoA configuration, Home Network Prefix (HNP) allocation mechanism, and handover procedure. Simulation results demonstrate that the proposed scheme can support the global mobility management by interworking between PMIPv6 and MIPv6. And they also show that the proposed scheme has an outstanding TCP/UDP throughput when compared with other schemes.

A Network-Assisted Femto Base Station Management Scheme in IEEE 802.16e System

In the WIMAX (IEEE 802.16e) femtocell environment, serving Base Station (BS) should periodically broadcast neighbor BS information including femtocell to support mobility. As a neighbor list increases, it leads to increasing scanning overheads and wasting air resources. Hence, in this paper we propose a network-assisted femto BS management scheme, using a triangulation mechanism and a femto BS monitoring scheme. The simulation results show that the proposed scheme improves scanning performance and avoids wasting air resources compared with the conventional scheme of IEEE 802.16e system.

Load-aware routing protocol for multi-radio Wireless Mesh Networks

This paper addresses the interference and load imbalance problems in multi-radio infrastructure mesh networks where each mesh node is equipped with multiple radio interfaces and a subset of nodes serve as Internet gateways. To provide backbone support, it is necessary to reduce interference and balance load in wireless mesh networks (WMNs). Therefore, this paper proposes a Load-aware routing protocol for multi-radio WMNs, called LMR. A load balancing technique and load-aware channel selection are both incorporated into the route discovery phase of the routing protocol, thereby helping to find paths that are better in terms of balancing load and reducing the inter-flow and intra-flow interference in multi-radio networks. Simulation results show that LMR can significantly enhance the overall network performance in multi-radio mesh networks.

Multihoming Support Scheme for Network Mobility Based on Proxy Mobile IPv6

This paper proposes a practical solution to support multihoming in NEMO based on proxy mobile IPv6. During each registration, all mobile network prefixes are registered with the home network to realize the benefit of multihoming. Plus, L2-tunnels and information sharing among mobile routers in NEMO allow mobile routers to achieve fault tolerance and path selection. The proposed scheme is validated using the OPNET simulator.

IP mobility support with a multihomed mobile router

This paper proposes a multihoming-based seamless handover scheme using a mobile router with dual egress interfaces for wireless train networks. The proposed scheme deploys dual antennas which are individually located at each end of the train for space diversity and connected to each egress interface of a mobile router. Since one of the two egress interfaces of the mobile router can continuously receive packets through its antenna while the other is undergoing a handover, the proposed scheme can support a seamless handover providing no service disruption or packet loss.