• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.11 no.6
• /
• pp.2831-2847
• /
• 2017

In this paper, a joint destination-relay selection and antenna mode selection scheme for full-duplex (FD) relay network is investigated, which consists of one source node, N FD amplify-and-forward (AF) relays and M destination nodes. Multiple antennas are configured at the source node, and beamforming technique is adopted. Two antennas are employed at each relay, one for receiving and the other for transmitting. Only one antenna is equipped at each destination node. In the proposed scheme, the best destination node is firstly selected according to the direct links between the source node and destination nodes. Then the transmit and receive mode of two antennas at each relay is adaptively selected based on the relaying link condition. Meanwhile, the best relay with the optimal Tx/Rx antenna configuration is selected to forward the signals. To characterize the performance of the proposed scheme, the closed-form expression of the outage probability is derived; meanwhile, the simple asymptotic expressions are also obtained. Our analysis shows that the proposed scheme obtains the benefits of multi-relay diversity and multi-destination diversity. Moreover, extra space diversity in the medium SNR region can be achieved due to the antenna selection at the relay. Finally, Monte-Carlo simulations are provided to consolidate the analytical results, and show the effectiveness of the proposed scheme.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.9
• /
• pp.341-349
• /
• 2021

This study is conducted to fill the research gap in proposing and testing the relationship between "Attitudes about the overall image of the destination", "Subjective norms" and "Perceived behavioral control". Simultaneously, we examine the relationship between these variables and tourists' "intent to choose a destination.". While most previous studies only deal with the relationship between destination image and intended behavior of tourists, this study uses the theory of planned behavior (Ajzen, 1991) to explain the intended behavior of tourists. In addition, the Theory of Destination Image (Echtner & Ritchie, 1991) is used to explain the factor "attitudes about the overall image of the destination", contribute to supplementing and perfecting the Theory of Planned Behavior. This study uses a Structural Equation Modeling (SEM) to analyze a sample of 993 observations, the subjects of which are international tourists to Vietnam, to test the relationship between second-order constructs. The test results show that "Subjective norms" and "Perceived behavioral control" have an impact on "Attitudes about the overall image of the destination". Moreover, all these three factors have an impact on "Intent to choose destination", in which the factor "Perceived behavioral control" has the greatest impact on "intention to choose destination".

• Journal of the Korean Geographical Society
• /
• v.43 no.6
• /
• pp.938-950
• /
• 2008

This study was to investigate if there were any significant relationships between cultural destination selection attributes and travel satisfaction according to segmented groups of cultural destination attributes. Survey questionnaire was developed based on the previous study and data were collected from on site survey, which was one of the famous cultural tourism destination in Korea such as Booyoe and Kongjoo. Six dimensions of cultural destination attributes were identified from factor analysis and three different segmented groups were determined from cluster analysis. Then, Multiple regression analysis conducted with six destination attributes as independent variables and one travel satisfaction as dependent variable, while Fisher's Z score for three segmented groups were considered as moderator's variable. The results showed that cultural destination attribute affected respondents' level of travel satisfaction and there was differences among segmented groups in terms of their affecting factors to the travel satisfaction. These findings suggested that there were different segmented groups of cultural destination selection attributes and each group pursued different cultural travel products and services.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.28 no.8A
• /
• pp.581-590
• /
• 2003

This paper proposes the routing path selection mechanism for source routing-based PtMP (Point-to-Multipoint) call in ATM switching system. Especially, it suggests PtMP routing path selection method that can share the maximum resource prior to the optimal path selection, guarantee the reduction of path calculation time and cycle prevention. The searching for the nearest branch point from destination node to make the maximum share of resource is the purpose of this algorithm. Therefore among neighbor nodes from destination node by back-tracking, this algorithm fixes the node crossing first the node on existing path having the same Call ID as branch node, constructs the optimal PtMP routing path. The optimal node to be selected by back-tracking is selected by the use of Dijkstra algorithm. That is to say, PtMP routing path selection performs the step of cross node selection among neighboring nodes by back-tracking and the step of optimal node selection(optimal path calculation) among neighboring nodes by back-tracking. This technique reduces the process of search of routing information table for path selection and path calculation, also solves the cycle prevention easily during path establishment.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.13 no.11
• /
• pp.5335-5353
• /
• 2019

The definition of the bandwidth efficiency (BE) of cognitive cooperative network (CCN) is the ratio between a number of the licensed slot(s) or sub-channel(s) used by the unlicensed users to transmit a single data packet from the unlicensed transmitter to unlicensed destination, and from unlicensed relay(s) to unlicensed destination. This paper analyzes and improves the BE in the underlay CCN with a new reactive relay selection under interference and power constraints. In other words, this paper studies how unlicensed cooperative users use the licensed network slot(s) or sub-channel(s) efficiently. To this end, a reactive relay selection method named as Relay Automatic Repeat Request (RARQ) is proposed and utilized with a CCN under interference and power constraints. It is shown that the BE of CCN is higher than that of cooperative transmission (CT) due to the interference and power constraint. Furthermore, the BE of CCN is affected by the distance of the interference links which are between the unlicensed transmitter to the licensed destination and unlicensed relay to the licensed destination. In addition, the BE for multiple relays selection over a CCN under interference and power constraints is also analyzed and studied, and it is shown that the BE of CCN decreases as the number of relays increases.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.11 no.5
• /
• pp.53-58
• /
• 2011

In this paper, we firstly propose a novel cooperative transmission protocol, which utilizes the advantages of mid-notes in the route from the source to the destination. Taking benefits from balancing between the received packet from the source and acknowledge message from the destination, the mid-node between the source and the destination is firstly considered to be the broadcaster. If its signal is successfully received from the source, it leads to consider the next nodes, which has closer distance to the destination than it. If one of these nodes correctly receives the signal, it performs broadcasting the signal to the destination instead of mid-node. Otherwise, the mid-node directs attention to these nodes being near to the destination. As the result, some nodes are unnecessary to be considered and passed over time. After that, we analyze some published selection relaying schemes based on geographic information to choose the best nodes instead of the instantaneous SNR as before. Finally, simulation results are given to demonstrate the correctness of the performance analyses and show the significant improvement of the selection relaying schemes based geographic information compared to the other ones.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2009.01a
• /
• pp.94-98
• /
• 2009

In this paper, we propose a new channel estimation scheme for amplify and forward cooperative diversity with relay selection. In order to select best relay, it is necessary to know channel state information (CSI) at the destination. Most of the previous works, however, assume that perfect CSI is available at the destination. In addition, when the number of relay is increased it is difficult to estimate CSI through all relays within coherence time of a channel because of the large amount of frame overhead for channel estimation. In a proposed channel estimation scheme, each terminal has distinct pilot signal which is orthogonal each other. By using orthogonal property of pilot signals, CSI is estimated over two pilot signal transmission phases so that frame overhead is reduced significantly. Due to the orthogonal property among pilot signals, estimation error does not depend on the number of relays. Simulation result shows that the proposed channel estimation scheme provides accurate CSI at the destination.

• International Journal of Contents
• /
• v.5 no.3
• /
• pp.24-32
• /
• 2009

Personal value and lifestyle have been regarded as the common factors in many studies of the destination selection. And the evaluations by visitors or tourists of certain destinations have been conducted in many respects. Based on those influential factors and measures from the review of the previous researches, this article considers the impact of residents' evaluation of the tourism resources in their own resident area on selecting destinations of their future overseas trips as well as their personal value and lifestyle. This article is aimed to reveal whether the impact exists, and if so, to what extent this impact can expand. According to the result, perception of tourism resources in residential area has impact on preferred destination, although its impact was relatively less than those of personal value and lifestyle. The more highly perceived the tourism resources are found, the more preferred tourist destination with abundant tourism attractions are. And the lowly perceived the cost of living in residential area is found, the more preferred the consumption-oriented tourist destinations are. It would be helpful for the product developers like travel agents or product marketers to know and predict the tendency of people s present evaluation of their areas and the future destination selection tendency for their trips.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.2A
• /
• pp.107-112
• /
• 2009

Spectral efficiency of current two-phase cooperative communications protocols is low since in the second time the relay forwards the same signal received from the source to the destination, the source keeps silent in this time. In this paper, we propose a novel cooperative communications protocol where the signal needed to transmit to the destination is sent in both phases, the source and the relay also transmit different signal to the destination thus no loss of spectral efficiency. This protocol performs signal selection based on log-likelihood ratio (LLR) at relay and maximum likelihood (ML) detection at destination. While existing protocols pay for a worse performance than direct transmission in the low SNR regime which is of special interest in ad hoc networks, ours is better over the whole range of SNR. In addition, the proposal takes advantages of bandwidth efficiency, long delay and interference among many terminals in ad hoc network. Simulation results show that the proposed protocol can significantly save total energy for wireless ad hoc networks.

• Journal of Communications and Networks
• /
• v.18 no.3
• /
• pp.320-326
• /
• 2016

In existing literature on multiple-input multiple-output (MIMO) relaying communication systems, antenna selection is often implemented by maximizing the channel capacity or the output single-to-noise ratio (SNR). In this paper, we propose an energy-efficient low-complexity antenna selection scheme for MIMO relaying communication systems. The proposed algorithm is based on beamforming and maximizing the Frobenius norm to jointly optimize the transmit power, number of active antennas, and antenna subsets at the source, relaying and destination. We maximize the energy efficiency between the link of source to relay and the link of relay to destination to obtain the maximum energy efficiency of the system, subject to the SNR constraint. Compared to existing antenna selection methods forMIMO relaying communication systems, simulation results demonstrate that the proposed method can save more power in term of energy efficiency, while having lower computational complexity.