• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.1
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• pp.191-197
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• 2012

In this paper we propose the FQSM(Fairness and QoS Supporting MAC) protocol that supports fairness and Quality of Service(QoS). The received or measured data traffics will be assigned a priority level according to its transmission urgency in the FQSM. And the load prediction algorithm is used to support the fairness between different priority traffics. For this, the buffer length values of the nodes are continuously monitored for a some period. Based on the buffer length variations for this period, the order of transmission is determined. FQSM also adapts cross-layer concept to rearrange the data transmission order in each sensor node's buffer, saves energy consumption by allowing few nodes in data transmission, and prolongs the network lifetime.

• The Journal of Information Technology
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• v.8 no.3
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• pp.131-142
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• 2005

The principles on which the Internet was designed and has evolved were first laid out in an explicit way 20 years age. The basic principle is that in layered communications network such as the Internet, functions should always be implemented at the end systems whenever the option exists. This applies to all functions that can be implemented either in the network or at the end systems. End-to-end arguments have recently been reexamined as the Internet and its uses have evolved, and a new set of requirements has begun to emerge. In addition to these, it add a new, and perhaps more important, requirement to this list in the case of heterogeneous networks: the proliferation of unpredictable wireless networks. Wireless networks must cope with dynamic link conditions not present in wired infrastructures, which place a heavy burden on quality of service management solutions. Managing QoS in the face of constantly changing operating conditions demands dynamic management approaches that span multiple layers in the protocol stack. Such as cross-layer design approaches have recently received attention in the context of cellular and mobile special networks. This article introduce the notion of network predictability and describe its relationship to achievable QoS. This relationship is used to propose a framework for cross layer design that can be used to guide development efforts and direct investment decisions for future networks.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.241-252
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• 2024

We analyze the types of Web3 business model innovation (BMI) of the six major Korean game companies by market size. As a result of the analysis, Nexon is watched as the adapter. It introduces blockchain (BC) layer 2, 'Polygon' to the extended ecosystem such as the creator's secondary creation, item utility, and compensation experience using the existing core intellectual property (IP). KakaoGames and Neowiz are watched as the adventurers. KakaoGames introduces BC layer 2, 'Polygon' and 'Near Protocol' to various experiments using tokenomics models in casual games and massively multiplayer online role-playing games (MMORPGs) using several existing popular IPs. Neowiz also introduces BC layer 2, 'Polygon' and 'Avalanche' to the IntellaX platform using existing game IPs. As the reinventor, Netmable positions as a game publisher that releases third-party games based on multi-chain infrastructure such as Klaytn, BNB Chain, Near Protocol, Aptos Foundation, and introduces BC to new core IPs. Finally, there are Wemade and Com2us as the mavericks. They aim to be the Web3 platform operators that create a BC layer 1 ecosystem and provide services that encompass BC games, GameFi, and non-fungible tokens (NFTs). Here are the implications of the four types of BMI. In terms of infrastructure, Nexon, KakaoGames, and Neowiz try to introduce a part of cross-chain, whereas Netmable tries to move toward a complete multi-chain strategy, and Wemade and Com2us also try to consider multi-chain, even if they have the full BC introduction. In terms of defending against market decline, Nexon and Netmable have a different position. Nexon which has a greater market dominance, only tries to continuously experiment, but Netmable is aggressively focusing on monetizing new products. Attacks on growth aspirations also show two different positions. KakaoGames and Neowiz only try to aggressively explore, while WeMade and Com2us try to set new standards for industrial innovation.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.3-9
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• 2015

The wireless communication system adopts an appropriate retransmission scheme on each system protocol layer to improve reliability of data transmission. In each system protocol layer, the retransmission scheme operates in independently other layers and operates based on the parameters without reference to end-to-end performance of wireless communication system. For this reason, it is difficult to design the optimal system parameters that satisfy the QoS requirements for each service class. Thus, the performance analysis of wireless communication system is needed to design the optimal system parameters according to the end-to-end QoS requirements for each service class. In this paper, we derive the mathematical model to formulate the end-to-end performance of wireless communication system. We also evaluate the performance at the MAC and transport layers in terms of average spectral efficiency and average transmission delay. Based on the results of performance evaluations, we design the optimal system parameters according to the QoS requirements of service classes. From the results, the HARQ combined with AMC is appropriate for the delay-sensitive service and the ARQ combined with AMC is appropriate for a service that is insensitive to transmission delay. Also, the TCP can be applied for the delay-insensitive service only.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.5
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• pp.2433-2452
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• 2017

Recently, the pipeline-forwarding has been proposed as a new technique to resolve the end-to-end latency problem of the duty-cycle MAC protocols in Wireless Sensor Networks (WSNs). Some protocols based on this technique such as PMAC and PRI-MAC have shown an improvement not only in terms of reducing end-to-end latency but also in terms of reducing power consumption. In these protocols, however, the sensor nodes still waste a significant amount of energy for unnecessary idle listening during contention period of upstream nodes to check the channel activity. This paper proposes a new pipeline-forwarding duty-cycle MAC protocol, named RP-MAC (Reduced Pipelined duty-cycle MAC), which tries to reduce the waste of energy. By taking advantage of ACK mechanism and shortening the handshaking procedure, RP-MAC minimizes the time for checking the channel and therefore reduces the energy consumption due to unnecessary idle listening. When comparing RP-MAC with the existing solution PRI-MAC and RMAC, our QualNet-based simulation results show a significant improvement in term of energy consumption.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.4
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• pp.40-46
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• 2011

Wireless Sensor Networks(WSNs) have shown a lot of good outcomes in providing a various functions depending on industrial expectations by deploying ad-hoc networking with helps of light loaded and battery powered sensor nodes. In particular, it is strongly requested to develop an algorithm of cross-layer control between 2-layer and 3-layer to deriver the sensing data from the end node to the sink node on time. In this paper, based on the above observation we have proposed an IEEE802.15.4 based self priority routing scheme under UC Berkely TinyOS platform. The proposed beacon based priority routing (BPR) algorithm scheme utilizes beacon periods in sending message with embedding the high priority data and thus provides high quality of service(QoS) in the given criteria. The performance measures are the packet Throughput, delivery, latency, total energy consumption. Simulation results under TinyOS Simulator(TOSSIM) have shown the proposed scheme outcome the conventional Ad hoc On-Demand Distance Vector(AODV) Routing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.768-777
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• 2020

In this paper, we describe recent research results on AODV routing protocol, which is widely deployed at mobile ad hoc networks, and AODV related routing protocols with multi-path routing schemes. We suggest the critical problems which minimum hop routing schemes have, such as AODV routing protocol, and then, propose a new C-AODV routing protocol with two routing metrics: the primary metric is the hop count, the secondary metric is the sum of link delay times. We implemented C-AODV protocol by modifying AODV at the NS-3, and thus, elaborate on how we change the original AODV source code of NS-3 in order to implement the C-AODV scheme. We show numerical comparison of C-AODV scheme with the original AODV scheme and then, discuss how much the C-AODV enhances routing performance over AODV protocol. In conclusion, we present future research items.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.6
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• pp.103-110
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• 2009

We propose a novel routing protocol selection scheme based on the application feature in wireless mesh network. Each application has its own feature such as its packet size. For example, text messenger generates short size packets and file transfer application generates long size packets. Routing protocols in wireless mesh network discover the route with different features. Some find shortest hop routes; others find the routes consisting of high bandwidth though they have more hops. The proposed scheme selects the routing protocol by matching the feature of routing protocol and that of application. This paper shows the system that we have developed for supporting mesh routing as well as the proposed scheme and experimental results.

• Journal of Communications and Networks
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• v.10 no.2
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• pp.213-220
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• 2008

This paper analyzes a broadcasting technique for wireless multi-hop sensor networks that uses a form of cooperative diversity called opportunistic large arrays (OLAs). We propose a method for autonomous scheduling of the nodes, which limits the nodes that relay and saves as much as 32% of the transmit energy compared to other broadcast approaches, without requiring global positioning system (GPS), individual node addressing, or inter-node interaction. This energy-saving is a result of cross-layer interaction, in the sense that the medium access control (MAC) and routing functions are partially executed in the physical (PHY) layer. Our proposed method is called OLA with a transmission threshold (OLA-T), where a node compares its received power to a threshold to decide if it should forward. We also investigate OLA with variable threshold (OLA-VT), which optimizes the thresholds as a function of level. OLA-T and OLA-VT are compared with OLA broadcasting without a transmission threshold, each in their minimum energy configuration, using an analytical method under the orthogonal and continuum assumptions. The trade-off between the number of OLA levels (or hops) required to achieve successful network broadcast and transmission energy saved is investigated. The results based on the analytical assumptions are confirmed with Monte Carlo simulations.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.25-33
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• 2008

Video telephony is a representative service in 3G mobile network. And there have been efforts to improve quality of video telephony service in different fields. In Korea, the leading mobile service provider SKTelecom and KTF service the WCDMA network as 3G mobile network. Now, more than a million people is using the network. In this paper, we study about video telephony over WCDMA network. and propose error minimizing algorithm using cross-layer adaptation between physical layer and video codec. We simulated 3G-324M protocol with MPEG-4 video codec, and simulation results show suggested algorithm improve packet transmission rate for improving quality of video telephony service.