• The KIPS Transactions:PartC
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• v.14C no.2
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• pp.171-178
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• 2007

In mobile ad hoc networks, an application scenario requires mostly group mobility behavior in the mix of group moving nodes and individually moving nodes. The nodes of those applications tend to belong to the movement group with similar movement behavior. Group mobility is one of the good methods to improve scalability, and reduces the protocol overhead. In this paper, we propose the multicast architecture which regards nodes that have equal group mobility in the heterogeneous group mobility network as the single entity with the multiple interfaces and composes multicast tree, The logical cooperative entity-based multicast architecture accommodates the scalability, the multicast tree simplification, and the protocol overhead reduction which arc obtained from the hierarchical multicast architecture, while it maintains the nat multicast architecture for the data transmission. It also prevents the concentration of the energy consumption dispersing data forwarding load into the several ingress/egress nodes. Results obtained through simulations show that logical cooperative entity based multicast protocol with multiple interfaces offers the protocol scalability and the efficient data transmission.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.10
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• pp.168-174
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• 2015

In this paper, we analyze the performance of cooperative communication techniques on an underwater channel. By analyzing the BER performance of cooperative transmission protocol and combining types ERC, FRC, SNRC and ESNRC on underwater channel, through the result, we can choose an a proper cooperative technique for an underwater channel. The analysis of BER performance is achieved by a computer simulation.

• Journal of Communications and Networks
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• v.13 no.3
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• pp.240-249
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• 2011

Cooperative diversity protocols have attracted a great deal of attention since they are thought to be capable of providing diversity multiplexing tradeoff among single antenna wireless devices. In the high signal-to-noise ratio (SNR) region, cooperation is rarely required; hence, the spectral efficiency of the cooperative protocol can be improved by applying a proper cooperation selection technique. In this paper, we present a simple "cooperation selection" technique based on instantaneous channel measurement to improve the spectral efficiency of cooperative protocols. We show that the same instantaneous channel measurement can also be used for relay selection. In this paper two protocols are proposed-proactive and reactive; the selection of one of these protocols depends on whether the decision of cooperation selection is made before or after the transmission of the source. These protocols can successfully select cooperation along with the best relay from a set of available M relays. If the instantaneous source-to-destination channel is strong enough to support the system requirements, then the source simply transmits to the destination as a noncooperative direct transmission; otherwise, a cooperative transmission with the help of the selected best relay is chosen by the system. Analysis and simulation results show that these protocols can achieve higher order diversity with improved spectral efficiency, i.e., a higher diversity-multiplexing tradeoff in a slow-fading environment.

• Journal of Korea Multimedia Society
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• v.15 no.12
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• pp.1464-1474
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• 2012

In this paper, we propose a QoS (Quality of Service)-aware and cooperative resource reservation scheme using cross-layer link adaptation for wireless high definition video transmission through UWB (Ultra Wide Band) network with D-MAC (Distributed Medium Access Control). A wireless high definition video transmission system usually requires stable high throughput even without line-of-sight, e.g., a destination device in another room separated by a wall. Since the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme causes lots of DRP resource reservation conflicts due to failure of beacon detection in wireless channel environment, overall performances of the WiMedia D-MAC can be deteriorated. And the current WiMedia MAC standard has not considered QoS provisioning even though QoS parameters such as a range of service rates are provided to each traffic stream. Therefore, we propose Relay DRP protocol with QoS-based relay node selection criterion, which makes a relay path to avoid DRP resource reservation conflicts and guarantee QoS more stably through cross-layer link adaptation of cooperative relay transmission scheme and is compliant with the current WiMedia D-MAC protocol. Simulation results demonstrate performance improvements of the proposed method for throughput and QoS provisioning.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.47-53
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• 2013

In this paper, we propose an incremental cooperative transmission protocol in two-way underlay cognitive radio networks. In the proposed protocol, two secondary sources attempt to transmit their packet to each other with help of a secondary relay under interference constraint. For performance evaluation, we derive exact closed-form expressions of average outage probability over Rayleigh fading channel. Then, we perform Monte Carlo simulations to verify the derivations. Results present that the simulation and theoretical results are in good agreement and the outage performance of the proposed protocol is better than that of two-way direct transmission protocol.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.3
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• pp.39-45
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• 2013

In this paper, we propose a cooperative relaying protocol using Fountain codes for secondary network under interference constraint. In the proposed protocol, a secondary source uses Fountain codes to transmit its message to a secondary destination with help of a secondary relay. The secondary source and relay operate in the underlay model, in which they must adapt their transmit power so that the interference caused at a primary user is lower than an allowable threshold. To evaluate performance of the proposed protocol, we derive the expressions of average number of transmission times over Rayleigh fading channel. Various Monte-Carlo simulations are presented to verify the derivations.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.185-194
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• 2006

In this paper, we first propose a power-and-bandwidth efficient cooperative transmission protocol where a sensor node assists two others for their data transmission to a clusterhead in WSNs (Wireless Sensor Networks) using LEACH (Low-Energy Adaptive Clustering Hierarchy). Then we derive its closed-form BER expression which Is also a general BER one for the decode-and-forward protocol (DF) and Prove that the proposed protocol performs as same as the conventional DF but obtains higher spectral efficiency. A variety of numerical results reveal the cooperation can save the network power up to 11dB over direct transmission at BER of $10^{-3}$.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.2
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• pp.23-28
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• 2008

In this paper, we propose location-aided cooperative routing protocol (LACARP) for supporting power saving and stable route lifetime in mobile ad-hoc wireless sensor networks. The main ideas and features of the proposed routing protocol are as follows. First, the definition of the area of route search using location-based information to support power saving transmission. Second, the expect zone-based establishment of routing route within the area of route search. Third, the cooperative-aided transmission method. In the operation of data transmission over the established rout the datas are transmitted via both the established route and cooperative route aided by neighbor nodes. The performance evaluation using OPNET(Optimized Network Engineering Tool) shows the LACARP can improve the packet delivery ratio and power saving transmission efficiently.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.223-224
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• 2008

Automatic repeat request (ARQ) protocol is attention for recent years as one protocol for reliable, accurate signal at the destination. However, in almost recently proposed ARQ protocols, the authors only consider advantage about the diversity gain. In this paper, we propose a novel cooperative ARQ protocol with advantage about the bandwidth in which the source sends a number of frames before stopping and worrying about the acknowledgment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.11
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• pp.2636-2656
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• 2013

To improve the cooperative efficiency of node cooperation and multiple access performance for multihop wireless networks, a priority-differentiated cooperative medium access control protocol with contention resolution (CRP-CMAC) is proposed. In the protocol, the helper selection process is divided into the priority differentiation phase and the contention resolution phase for the helpers with the same priority. A higher priority helper can choose an earlier minislot in the priority differentiation phase to send a busy tone. As a result, the protocol promptly selects all the highest priority helpers. The contention resolution phase of the same priority helpers consists of k round contention resolution procedures. The helpers that had sent the first busy tone and are now sending the longest busy tone can continue to the next round, and then the other helpers that sense the busy tone withdraw from the contention. Therefore, it can select the unique best helper from the highest priority helpers with high probability. A packet piggyback mechanism is also adopted to make the high data rate helper with packet to send transmit its data packets to its recipient without reservation. It can significantly decrease the reservation overhead and effectively improve the cooperation efficiency and channel utilization. Simulation results show that the maximum throughput of CRP-CMAC is 74%, 36.1% and 15% higher than those of the 802.11 DCF, CoopMACA and 2rcMAC protocols in a wireless local area network (WLAN) environment, and 82.6%, 37.6% and 46.3% higher in an ad hoc network environment, respectively.