Joo Sang Youn

Quick Local Repair Scheme using Adaptive Promiscuous Mode in Mobile Ad Hoc Networks

In mobile ad hoc networks (MANETs), there is frequently disconnected a route consisting of multi- hop from a source to a destination because of the dynamic nature such as the topology change caused by nodes’ mobility. To overcome this situation, existing routing protocols for MANETs have performed route repair scheme to repair the disconnected route. However, existing reactive routing protocols have the problem which is that a source node unnecessarily performs re-discovers the whole path when just one node moves, even if the rest of path needs not to be re-arranged. Therefore, the time for re-discovery of the whole path may often take too long. To solve the problem, we propose a new local repair scheme using promiscuous mode. Our scheme is mainly composed of two parts: adaptive promiscuous mode and quick local repair scheme. Adaptive promiscuous mode is to repeat the switching processes between promiscuous mode and nonpromiscuous mode to overcome energy limit caused by using promiscuous mode in overall time and quick local repair scheme is to fast perform the local re-route discovery process with the information of the active connection in the local area acquired by promiscuous mode. With simulation in the various number of connection, We demonstrate the better network performances achieved with the proposed schemes as compared with AODV as reference model that do not provide local repair scheme.

New service differentiation model for end-to-end qos provisioning in wireless ad hoc networks

In this paper, a new QoS model is presented for end-to-end service provisioning in wireless ad hoc networks. Many previous works focus on the packet scheduling mechanism using multiple service classes implemented for traffic prioritization based service differentiation. However, this paper concentrates on a scheme for dynamically selecting a proper one among several forwarding classes that perform different service rate according to service requirements. There service requirements include low delay, high throughput, and low loss. The proposed solution is a new QoS provisioning model called Dynamic Hop Service Differentiation (DHSD). This model supports soft QoS provisioning to reduce network overhead and wireless PHB (WPHB) to achieve the end-to-end QoS required by applications. The proposed QoS model is evaluated using OPNET simulation. We show that this model outperforms both best-effort and strict priority service models in wireless ad hoc network environments.

A local repair scheme with adaptive promiscuous mode in mobile ad hoc networks

In current routing protocols in ad hoc networks, a source node unnecessarily re-discovers the whole path when just one node moves, even if the rest of path needs not to be re-arranged. The time for re-discovery of the whole path may often take too long and affects the network efficiency adversely. In this paper, a local repair scheme has been proposed, where the source node recovers the route breakage caused by a shifting of node with an aid of adjacent node instead of re-routing the whole path. Adjacent nodes are under operation in adaptive promiscuous mode. Consequently, the proposed scheme has advantages in shortening the recovery time of the route breakage and in minimizing the energy consumption under promiscuous mode. The ns-2.27 simulator has been utilized for the evaluation of the proposed scheme.

QoS model for improving end-to-end service in 802.11e-based wireless ad hoc networks

In order to obtain better performance in wireless ad hoc networks, the majority of existing work focuses on the multi-priority based packet scheduling mechanism under multiple service classes, admission control and rate policing, according to application requirements and network conditions. In addition, no studies have reported on the feasibility and scalability of adapting the IEEE 802.11 EDCA scheme in such networks. This paper presents a new QoS provisioning model called Dynamic Hop Service Differentiation (DHSD), which performs dynamic class selection based on estimation of each service class (AC) in 802.11e based ad hoc networks. This model is designed for Soft QoS provisioning. Performance evaluation is performed by simulation using OPNET. It is demonstrated that this QoS model outperforms existing service models in wireless ad hoc environments.

Novel route metric for high-throughput in multi-rate wireless ad hoc networks

This paper presents the route metric, the Expected Cumulative Service Latency (ECSL), which allow any routing protocol to select a route with the high-throughput in the multi-rate wireless ad hoc networks. The ECSL route metric finds a route with minimal end-to-end forwarding time expected to successfully deliver a packet to the destination. In such networks, existing route metrics for route discovery only use the link quality metric based on the expected amount of medium time it would take by successfully transmitting a packet. Thus, in these schemes, the current state of traffic in network is not taken into account. Therefore, this may easily result in the congested network. In addition, the application has no way to improve its performance under a given network traffic condition. In this paper, we propose the route metric, the expected end-to-end latency that is estimated with the number of packets waiting for transmission in queue at relay nodes and the link transmission time as well as a new routing protocol using the proposed metric. The performance of the proposed route metric is evaluated by OPNET simulator. We show that the performance of the AODV routing protocol using the ECSL route metric outperforms that of the routing protocols using other existing route metrics in multi-rate ad hoc network.

Data forwarding protocol for reliable delivery service in wireless sensor networks

The end-to-end reliable data transport is one of important issues in large-scale wireless sensor networks (LS-WSNs). In this paper, the reliable data transport protocol, called the Data Forwarding Protocol (DFP), is proposed to improve the performance in wireless sensor environments consisting of mobile sensor nodes with low speed. The key idea of the protocol is that an Agent Host (AH), which plays rule of a source or a sink, estimates multi-split connections, to support reliable end-to-end deliver. Using AH nodes, the DFP locally performs local error control and flow control mechanism with low overhead in terms of an end-to-end connection. We evaluate the proposed DFP method using NS-2 simulator and prove that the performance of reliable delivery service can be increased to at least 30%, compared with that of traditional TCP-like end-to-end approach.

Priority-based recovery scheme improving network utilization in the IP over optical networks

This Paper presents a Priority Based Recovery Scheme (PBRS) improving the utilization of limited resource- i.e. light-paths- which is necessary when recovery mechanism occurred in the IP Over Optical Networks. PBRS is used in the RLG (Recovery Link Group) made by priority number of LP (Light path). We assumed there are three kinds of LPs by their traffic characteristics Mission-Critical, Best-Effort and Low-priority -in the RLG. When the LP faults are detected, primary LPs classified by the order of traffic priority choose recovery mechanism by their priority number value. In the priority based RLG, Each LP has its own recovery mechanism priority 1 LP (Mission-Critical traffic) use dedicated protection scheme, priority 2 LP (Best-effort traffic) uses preplanned restoration scheme and Priority 3 LP (Low-Priority traffic) uses dynamic restoration scheme. After recovery mechanism is accomplished, new LP Setup information based on the given priority information is transferred to ingress OXC (Optical Cross Connect) for the purpose of making new light path. OXC has structure capable of making new light paths or releasing light paths via signaling control to maintain consistent recovery capability, regardless of fault count, based on priority scheme. The PBRS has some advantages expanding availability of LPs that is limited resources in the optical network and designing the network that has consistent recovery capability. In this paper, we also present a Router and OXC structures, LP failure detection mechanism, and signaling procedures that are necessary to adopt PBRS. The performance and effectiveness of PBRS is demonstrated by means of statistical simulations on randomly generated mesh network topology.