• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.5
• /
• pp.18-24
• /
• 2013

Network coding has been extensively studied to increase the network throughput by exploiting the broadcast and overhearing capabilities. In this paper, we formulate a network utility maximization problem to improve the network utility in multichannel, multiradio and multisession wireless multihop network with intrasession network coding. To find the solution of this problem, we propose a congestion control, distributed rate control, and heuristic resource allocation algorithm. We find the network utility and evaluate the performance in multichannel, multiradio and multisession environment by using MATLAB. Finally, the results show that the proposed schemes can achieve throughput improvement by performing the network utility optimization in wireless multihop network.

• Proceedings of the Korean Information Science Society Conference
• /
• 2011.06a
• /
• pp.416-419
• /
• 2011

무선 센서 네트워크 환경에서 효율적인 데이터 수집 기업은 핵심적인 기반 기술이다. 클러스터 기반의 데이터 수집 기법은 데이터 병합 (aggregation) 의 효율을 최대화 시켜 센서 노드들의 에너지 소모를 최소화 시킨다. 하지만 기존의 클러스터링 기법은 균일한 네트워크 환경만을 고려하여 불균일하게 배포될 수 있는 실제 환경에는 적합하지 않다. 본 논문에서는 기존 기업들의 문제점을 해결하기 위해 불균일한 네트워크 환경에서도 에너지 효율적인 클러스터를 구축할 수 있는 기업을 제안한다. 제안하는 기법은 클러스터 헤드를 기준으로 최단 거리 홉 카운트 기법을 통해 논리적인 거리를 기반으로 클러스터 멤버를 구성한다. 이를 통해 불균일한 네트워크 환경에서도 클러스터들 간에 균형적인 멀티-홉 클러스터를 구축하여 네트워크 수명을 최대화 시킨다. 제안하는 기법의 우수성을 모이기 위해 기존 기법과 시뮬레이션을 통해 성능을 비교평가 하였다.

• Convergence Security Journal
• /
• v.15 no.3_1
• /
• pp.75-82
• /
• 2015

Recently, lot of researches on multi-level protocol have been done to balance the sensor node energy consumption of WSN and to improve the node efficiency to extend the life of the entire network. Especially in multi-hop protocol, a variety of models have been studied to improve energy efficiency and apply it in real system. In multi-hop protocol, we assume that energy consumption can be adjusted based on the distance between the sensor nodes. However, according to the physical property of the actual WSN, it's hard to establish this. In this paper, we propose low-power sub-cluster protocol to improve the energy efficiency based on the spread of distance. Compared with the previous protocols, the proposed protocol is energy efficient and can be effectively used in the wireless sensing network.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.5
• /
• pp.931-937
• /
• 2015

Distributed relay scheme for wireless ad hoc multi-hop multicast network composed of low-power and low-complexity wireless devices with high density is proposed. The proposed relay scheme is shown to be better than flooding, which is the distributed relay scheme applied to ZigBee, in the outage probability and the multicast transmission rate by simulations.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.10a
• /
• pp.657-658
• /
• 2015

In an wireless sensor network, energy efficient routing protocol is important for multi-hop transmission because senor nodes are powered by battery. In multi-hop transmission, specifice nodes are used and the battery power becomes low, it induce the asymetric remaining power among the nodes and makes the network lifetime reduced. In this paper, we propose a power-aware routing protocol which determines the routing path considering the remaining power of the nodes. Simulation results shows that the proposed routing scheme minimize the transmission delay and increase the network lifetime.

• Journal of Digital Contents Society
• /
• v.8 no.3
• /
• pp.323-328
• /
• 2007

Communication systems beyond 3G should provide more than 100 Mbps for wireless access. In addition to smart antennas, wireless multi-hop networks are proposed to increase the cell size and throughput. For example, Zigbee technology is expected to provide low cost and low power connectivity and can be implemented in wireless mesh networks larger than is possible with Bluetooth. Also, home embedded system using wireless mesh network is one of the key market areas for Zigbee applications. If the line-of-sight path is shadowed by home obstacles, a direct connection between the access point (AP) and the node is not possible at high frequencies. Therefore, by using multi-hop relay scheme the end node can be reached to AP. In this paper, the relaying of data between the AP and the end node is investigated and the throughput and PER(Packet Error Rate) are evaluated in multi-hop wireless mesh networks by using DSSS/BPSK system.

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

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.2
• /
• pp.452-458
• /
• 2014

In Wireless Sensor Networks the Medium access control (MAC) protocol has many challenges to solve such as reducing energy consumption, supporting QoS(quality of service) fairness, and reducing delivery delay. This paper proposed a low-delay supporting MAC protocol in multi-hop Wireless Sensor Networks. The proposed protocol uses the RB(rapid beacon) frame for reducing delivery delay. The RB frame is a modified IEEE 802.15.4 beacon frame. For sender adaptive-wakeup, the RB frame includes a seed number for determining of a receiver wakeup time. And for next hop receiver adaptive-wakeup, the RB frame includes the length of remaining data packet information. Results showed that our LD-MAC protocol outperformed other protocol in terms of data packet delivery delay.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.2
• /
• pp.459-465
• /
• 2014

Recently, multimedia data transmission becomes important issues in the wireless sensor network. For the multimedia data transmission in wireless sensor network, QoS (Quality of service) is an important factor to determine the system performance. AODV algorithm is one of the widely used algorithm for wireless ad-hoc environment. In AODV, the destination node selects the route with the smallest hop count. Since AODV only considers the hop count, the selected route could have low channel condition, and degrade QoS. In this paper, we propose a modified AODV algorithm that considers the successful transmission rate of each link. The proposed algorithm regards the number of retransmission which can be obtained from the successful transmission rate as the hop count, and applies the modified hop count to AODV. The advantage of the proposed algorithm is that the modified AODV can support QoS without significant change of the conventional algorithm.

• Journal of Korea Multimedia Society
• /
• v.14 no.7
• /
• pp.949-963
• /
• 2011

Generally, It is indispensible to use an ISP(In System Programming) tool for upgrading, patching, or changing the system software of the each sensor nodes in wireless sensor networks. While under a small number of nodes, the upgrading task is not a serious burden, however if there are a large number of nodes to be updated, the task is almost impossible to do for the given constrains such as limited budgets and resources. Based on this observation, in this paper we have proposed a novel upgrading scheme based on a single hop in IEEE 802.15.4 PAN(Personal Area Network)s. Simulation results have shown the scheme outcomes the conventional methods in the performance measures.