• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.17-22
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• 2013

In this paper, we propose a multi-hop cooperative transmission protocol over Rayleigh fading channels. In the proposed protocol, the multi-hop cooperative transmission is used to improve the system performance. Due to broadcast nature, we do not limit the receiving node to be only the next node, but the destination and all the nodes between the transmitting node and the destination. The proposed protocol can hence save the average transmit power, compared with multi-hop direct transmission protocol due to the skipped transmissions from some intermediate nodes or chosen relays. The proposed scheme is implemented and evaluated in mobile ad-hoc wireless networks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4825-4847
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• 2016

In this paper, we focus on the per-flow throughput analysis of IEEE 802.11 multi-hop ad hoc networks. The importance of an accurate saturation throughput model lies in establishing the theoretical foundation for effective protocol performance improvements. We argue that the challenge in modeling the per-flow throughput in IEEE 802.11 multi-hop ad hoc networks lies in the analysis of the freezing process and probability of collisions. We first classify collisions occurring in the whole transmission process into instantaneous collisions and persistent collisions. Then we present a four-dimensional Markov chain model based on the notion of the fixed length channel slot to model the Binary Exponential Backoff (BEB) algorithm performed by a tagged node. We further adopt a continuous time Markov model to analyze the freezing process. Through an iterative way, we derive the per-flow throughput of the network. Finally, we validate the accuracy of our model by comparing the analytical results with that obtained by simulations.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.68-75
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• 2008

Because ad hoc network is vulnerable to attacks such as routing disruption and resource consumption, it is in need of routing protocol security. In this paper, we propose an efficient and secure route discovery protocol for ad hoc network using symmetric key cryptography. This protocol has small computation loads at each hop using symmetric key cryptography. In the Route Reply, encryption/decrytion are used to guard against active attackers disguising a hop on the network.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.1
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• pp.113-121
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• 2007

Commonly, in the Sensor Network that composed with multiple nodes uses Ad-hoc protocol to communicate each other. Each sensed data packets are collected by base node and processed by Host PC. But the Ad-hoc protocol is too vulnerable to Sinkhole attack, where the intruder attracts surrounding nodes with unfaithful routing information, and then performs selective forwarding or changes the data passing through it. The Sinkhole attack increases overhead over the network and boosts energy consumption speed to decrease network's life time. Since the other attacks can be easily adopted through sinkhole attack, the countermeasure must be considered carefully. In this paper, we proposed the Hop-depth algorithm that detects intruder in Sinkhole attack and colluded nodes. First, the proposed algorithm makes list of suspected nodes and identifies the real intruder in the suspected node list through the Hop-depth count value. And recalculates colluder's path information to find the real intruder. We evaluated the performance of the proposed algorithm using NS2. We compared and analyzed the success ratio of finding real intruder, false positive ratio, false negative ratio, and energy consumption.

• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.191-198
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• 2007

A mobile ad-hoc network (MANET) is an autonomous, infrastructure-less system that consists of mobile nodes. In MANET, on demand routing protocols are usually used because network topology changes frequently. AODV, which is a representative on demand routing protocol, operates using the routing table of each node that includes next hop of a route for forwarding packets. It maintains the established route if there is not an expiration of route or any link break. In the paper, we propose a partially adaptive route maintenance scheme (AODV-PA) based on AODV, which provides dynamic route modification of initial route for selecting the effective route using not only next hop but also next-hop of next-hop (i.e. 2-hop next node) acquired through route discovery process. In addition, the proposed scheme additionally manages the routing table for preventing exceptional link breaks by route modification using HELLO messages. We use NS 2 for the computer simulation and validate that the proposed scheme is better than general AODV in terms of packet delivery ratio, latency, routing overhead.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1161-1167
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• 2003

The nodes of Ad hoc network are made up of location registration for sending informations and a great number of packet transmissions to maintain routing route among the nodes. Under this environment, a huge number of traffics would be generated as mobility variable occurs more than in physical network. Hence, in this paper, focused on to study the relationship of nodes to analyze the extent of the traffic in order to control the traffics of the multi-hop in Ad hoc.

• ETRI Journal
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• v.38 no.5
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• pp.922-933
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• 2016

IP header compression schemes offer a valuable measure for bandwidth preservation. Such schemes have been practically implemented in infrastructure-based IP networks for point-to-point links. However, minimal research and practical implementation efforts have been conducted in the direction of an IP header compression strategy that can meet the peculiar requirements of multi-hop ad hoc wireless networks. In this paper, we present a practically implemented multi-hop IP header compression scheme using the Robust Header Compression (ROHC) protocol suite. The scheme runs on a novel identifier (ID) based networking architecture, known as an ID-based ad hoc network (IDHOCNET). IDHOCNET additionally solves a number of bottlenecks of pure IP-based ad hoc networks that have emerged owing to IP address auto-configuration service, distributed naming and name resolution, and the role of an IP address as an identifier at the application layer. The proposed scheme was tested on a multi-hop test bed. The results show that the implemented scheme has better gain and requires only O (1) ROHC contexts.

• Journal of IKEEE
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• v.14 no.4
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• pp.312-316
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• 2010

We describe in this paper how to facilitate ad hoc routing with a particle filter in a hostile radio environment for multi-hop wireless ad hoc networks that connect multi-robots. The proposed scheme increases a connection's throughput by exploiting alternative links without going through the procedure of route discovery when link failure happens among multi-robots' networking. The scheme is implemented by using a particle filter to find strongly connected nodes. The filter estimates the probability distribution function in a sample-based manner with N particles. The particles are associated with a weight which represents the probability of the corresponding node to be the node with the best link. At every step of the estimation, the weights of particles are calculated and particles are resampled based on the weights. Since a node with the strongest link status possesses the largest number of particles, we take this node to forward the packets.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.361-363
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• 2005

최근의 컴퓨터 네트워킹 환경에서 무선 멀티미디어 응용 서비스에 대한 사용자의 요구는 날로 증가하고 있다. 그러므로 사용자에게 원활한 서비스를 제공위해서 QoS 보장을 위한 무선 네트워크 프로토콜의 설계는 중요하다. 본 논문에서는 무선 인터넷에서 QoS를 보장하기 위한 표준인 IEEE 802.11e[1]의 문제점들을 분석하고, Multi-Hop Ad Hoc Network에서 성능 향상을 위하여 Single-channel Jamming 신호를 기반으로 한 SJMAC(Sing1e-channel Jamming MAC) 프로토콜을 설계하고, NS2 모듈을 구현한 후에 성능 평가를 하였다. 기존 IEEE 802.11e과의 성능 비교를 위하여 NS2 (Network Simulator2)[2]에 SJMAC 모듈을 추가하여 제안된 프로토콜의 성능을 검증한다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.21 no.1
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• pp.15-22
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• 2013

In oceanic flight routes, HF radio and satellite data links have weather restrictions, long propagation delay and low data throughput. In this paper, we propose oceanic aeronautical communications scheme in the VHF band based on ad-hoc communication. The proposed scheme organizes autonomously a multi-hop network that is divided into multiple local network using aircraft to fly long-distance communication and supports a hybrid type of multiple access, which consists of random access and TDMA (Time Division Multiple Access) scheme. In addition, several algorithms to apply spatial reuse of transmission to multi-hop long range communication environments have been proposed. The proposed system proves performance improvement on delay time as an effective solution to communicate end-to-end on the oceanic flight routes and strengthens the reliability of oceanic aeronautical communication.