• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.119-126
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• 2011

When ZigBee network supports beacon transmission mechanism, ZigBee devices have the restriction of the transmission range from the coordinator. On the contrary, when it does not support beacon transmission, it is not easy to save the energy through turning into sleep mode. This paper proposes active slot allocation method that allocates a transmission time and does not use the beacon transmission mechanism. It is based on the ZigBee's distributed address assignment mechanism and supports the scalability. This paper explains the active slot structure and the allocation order and describes the operation of ZigBee devices. We verify the proposed mechanism through the simulation and show the performance evaluation. It can be useful on the industrial automation and the environmental surveillance.

• Journal of information and communication convergence engineering
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• v.6 no.1
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• pp.24-28
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• 2008

In RFID System, when multiple tags respond simultaneously, a collision can occur. A method that solves this collision is referred to anti-collision algorithm. Among the existing anti-collision algorithms, static framed slot allocation algorithm is very simple. But when the number of tags is variable, its performance degrades because of the fixed frame size. This paper proposes an optimal frame size allocation scheme that determines the frame size. The proposed scheme is based on the number of collision slots at every frame. According to the simulation results, the tag identification time is faster that of SFSA.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.11
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• pp.30-40
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• 2001

In this paper, we propose a dynamic slot allocation algorithm for efficient transmission of VBR services in wireless ATM networks. The proposed algorithm is based on a hybrid dynamic parameter(DP) control which combines the strength of in-band control and out-of-band control by considering the variation characteristics of buffer length in distributed mobile terminals. This algorithm consists of four sub-algorithms: dynamic parameter determination algorithm, dynamic parameter transmission algorithm, estimation algorithm of the number of request slots, and prorated-allocation algorithm. As the proposed allocation algorithm based on the hybrid DP control scheme can offer nearly precise MAC level estimations of the requirements for each VBR, the algorithm makes it possible to obtain ideal allocation efficiency. The allocation efficiency of the algorithm is shown by numerical analysis. Simulation results show that the proposed algorithm has better performance than conventional schemes in terms of allocation efficiency, delay and cell loss ratio under VBR traffic.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.73-78
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• 2002

In WATM networks, in order to perform dynamic slot allocation required slots of mobile terminals are estimated based on DP (Dynamic Parameter) reflecting characteristics of traffic. In VBR (Variable Bit Rate) traffic, slot allocation is done at MT considering both time-dependent characteristics and QoS (Quality of Service) requirements. In this paper, DPs-buffer state information and buffer state change-are transmitted through in-band signaling. BS (Base Station) performs dynamic slot allocation considering traffic characteristics of each MT (Mobile Terminal), in other words, buffer state information informs the potentiality of 'buffer full state'to BS if MT buffer is over the specific threshold value and buffer state change notifies change in buffer state of incoming cells to MT. If buffer state information is equal to 'low (more than threshold)' and 'abrupt increase' it generates 'buffer full' state cell transmission delay or cell loss might occur. At this time BS should assign additional slots to MT, and then MT consumes cells in its buffer. In simulation, the proposed scheme shows better performance in cell delay and loss than EPSA (Estimation-Prorated Slot Assignment) in-band scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1492-1509
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• 2017

The wireless sensor network (WSN) is a key technology to support the Internet of things (IoT) paradigm. The efficiency of the MAC protocol in WSN is very important to take scalability with restricted wireless resources. The DESYNC-TDMA has an advantage of simple distributed slot allocation inspired by nature, but there is a critical disadvantage of split slots by firing message. The basic split slot model has less efficiency for continuous packet transmitting because of wasting of the slots less than the packet size. In this paper, we propose a firing offset adjustment scheme to improve the efficiency of slot utilizations, which can manage the slot assigned to each node as a single large block, called the single slot model. The performance analysis models for both the existing and the proposed schemes are also derived. Experimental results show that the proposed method provide better efficiency of slot utilization than the existing schemes without any loss of the nature of the desynchronization.

• Journal of Internet of Things and Convergence
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• v.10 no.4
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• pp.109-115
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• 2024

This paper proposes an interference recognition-based resource allocation (IaRA) scheme for very high frequency (VHF) data exchange-terrestrial (VDE-TER) to ensure the reliability of automatic identification system (AIS) message transmission in a coastal environment with dense vessels. To this end, IaRA conducts channel selection and slot allocation based on scheduling information obtained through monitoring VHF data exchange system (VDES) channels. The simulation results show that IaRA achieved an 8.79% higher packet delivery ratio (PDR) and a 9.69% lower channel interference ratio (CIR) compared to the VDE-TER resource allocation scheme of the existing VDES standard.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.35S no.1
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• pp.1-13
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• 1998

The next generation of wireless network will be problably developed as a mobile communications which will support ATM-based multiMedium traffic. We need to develop an dffective MAC protocol in order to support multimedia traffic having variety of QoS characteristics on wireless neteworks. In this paper, we propose a MAC protocol a MAC protocol where mobile terminals having cells to transmit, request slots to base station through requested slot then the base station analyze parameters from mobile and allocate slots to mobile according to priority. The multimedia slot allocation(MSA) protocol divides multimedias applications into real-time/ variant and non real-time services. Entire slots of the frameare partitioned proportionallyby sizeof bandwidth according to types of services, so that related services can use allocated-slots in priority. The proposed algorithm guarantees real time operation since real-time service share slots allocated for non real-real services. The algorithm whih divides slots of the frame is called as an Algorithm A, otherwise as an Algorithm B. The simulation compares by average delay time and cell loss probability between Algorithm and Algorithm B by increasing number of mobile terminal using the proposed MAC protocol. the simulation result for real-time services shows that average delay time and cell loss probability of Algorithm A is better than those of Algorithm B.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.32 no.1
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• pp.61-70
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• 2024

In response to the continuously increasing demand for air travel, various studies are being conducted. This research focuses on the design of a simulation model for improving airport slot allocation in the strategic phase. It addresses three aspects of model design, introducing considerations such as the objective function. Additionally, it explains the conceptual procedures for the overall simulation operation and detailed processes within the model including input and output data. Emphasizing the SAL, this study excludes policy and qualitative judgments from its scope. The target airport for application will be confirmed in future research. This study marks a crucial first step toward optimizing air traffic flow, with expectations of contributing to the enhancement of operational efficiency at airports.

• Journal of information and communication convergence engineering
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• v.14 no.1
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• pp.21-25
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• 2016

N-screen is a promising technology to improve support for multimedia multicasting, content sharing, content mobility, media scalability, and seamless mobility. In this paper, the WiMedia distributed-MAC (D-MAC) protocol is adopted for development of a seamless N-screen wireless service. Furthermore, to provide a multi-hop, one source multi-use N-screen service through point to point streaming in a seamless D-MAC protocol, a dynamic multi-frame transmission technology is proposed. In this technology, a dynamic time slot allocation scheme and a multi-hop resource reservation scheme are combined. In the proposed dynamic time slot allocation scheme, two thresholds, a hard threshold and a soft threshold, are included to satisfy the power consumption and delay requirements. A multi-frame DRP reservation scheme is proposed to minimize end-to-end delay during the multi-hop transmissions between N-screen devices. The proposed dynamic multi-frame transmission scheme enhances N-screen performance in terms of the multi-hop link establishment success rate and link establishment time compared to the conventional WiMedia D-MAC system.

• Journal of information and communication convergence engineering
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• v.12 no.1
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• pp.14-18
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• 2014

A recent major development in computer technology is the advent of wearable computer systems. Wearable computer systems employ a wireless universal serial bus (WUSB), which refers to a combination of USB with the WiMedia wireless technical specifications. In this study, we focus on an integrated system of WUSB over wireless body area networks (WBANs) for wireless wearable computer systems. However, current WBAN MACs do not have well-defined quality of service (QoS) mapping and resource allocation mechanisms to support multimedia streams with the requested QoS parameters. To solve this problem, we propose a novel QoS-aware time slot allocation method. The proposed method provides fair and adaptive QoS provisioning to isochronous streams according to current traffic loads and their requested QoS parameters by executing a QoS satisfaction algorithm at the WUSB/WBAN host. The simulation results show that the proposed method improves the efficiency of time slot utilization while maximizing QoS provisioning.