• Journal of Korea Multimedia Society
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• v.19 no.3
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• pp.567-572
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• 2016

N-screen is an emerging technology to support multimedia multicasting, content sharing and content mobility. N-screen service providers should obtain the technology that provides the highest quality content seamlessly. Distributed nature of WiMedia distributed-MAC protocol can provide full mobility support, and achieves seamless medium access method in contrast to IEEE 802.15.3. So, in this paper, WiMedia distributed-MAC protocol is adopted and an asynchronous multicast transmission (AMT) technology is proposed to enhance performance of seamless N-screen wireless service based on distributed-MAC. The ACK frame transmissions are not required for multicast transmissions. By using this property in AMT, if a device is a multicast receiver, its reserved time slots can be reserved by the other devices with 1-hop distance. Furthermore, each N-screen device broadcasts and shares the information including an order in asynchronous traffic reservations to reduce conflicts in determining the transmission order of asynchronous N-screen packets. Therefore, AMT scheme expands the number of time slots available and throughputs for multicast and asynchronous traffic reservations when comparing with the distributed-MAC standard system. N-screen communications based on distributed-MAC with the proposed AMT shows a new framework for realizing N-screen wireless service with the full content mobility.

• Journal of Digital Contents Society
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• v.13 no.3
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• pp.469-476
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• 2012

Recently, as the smart devices such as smart phone and smart pad are becoming increasingly common, the number of the smart devices users is increasing explosively. Therefore, the mobile Internet traffic is tend to get more and more increasing, and thus it is expected that the demand for using mobile Internet traffic will be exponentially increasing annually worldwide. In addition, mobile communications operators concentrate on much efforts and investments in order to effectively solve these problems at home and abroad, and the interest on the network-based (i.e., PMIPv6-based) distributed mobility management technology, which effectively distributes the explosively increasing mobile Internet traffic, is getting larger and larger. In this paper, we address the overview and recent research trend of PMIPv6-based distributed mobility management technology, and also describe the necessity and future prospect for studying PMIPv6-based distributed mobility management technology.

• International journal of advanced smart convergence
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• v.7 no.4
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• pp.174-184
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• 2018

The efficiency and safety of social-overhead capital (SOC) public infrastructures have become an eminent social concern. In this regard, a continuous structural health monitoring has been widely implemented to oversee the robustness of such public infrastructures for the safety of the public. This paper deals with the analysis of a distributed mobility management (DMM) support for wireless sensor network (WSN) based information transmission system. The partial DMM support separates the data and control plane infrastructures, wherein, the control plane is managed by a particular mobility management network entity, while the data plane is distributed by the mobility anchors. The system will be able to optimize the information transmission for a wireless structural health monitoring of SOC public infrastructures specifically designed for bridges, and thus, guarantees the safety of public commuters.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.7
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• pp.1030-1040
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• 2018

In Distributed Mobility Management (DMM) protocol, the mobility functions are distributed to network edge closer to mobile users. DMM protocol has some advantages of low-cost traffic delivery, optimized routing path, high scalability. However, it needs many mobile anchors to exchange signaling messages and it results in a high signaling cost. Thus, previous works suggested the hybrid DMM protocol to reduce the high signaling cost for long-live sessions and this paper extends a hybrid scheme to the NEMO environment. The mobile routers are installed at vehicles and can move together with several mobile devices. So we can define the high-mobility property for mobile routers and suggest the hybrid scheme using this property. According to the high-mobility property of mobile routers, we can distribute the mobile anchors or allocate a centralized mobile anchor. In this paper, we mathematically analyze the performance of the proposed NEMO-enabled hybrid DMM protocol and show superior performance.

• Journal of Advanced Information Technology and Convergence
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• v.10 no.2
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• pp.73-81
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• 2020

The number of mobile devices roaming into a ubiquitous city (u-city) continues to rise as wireless systems have been widely deployed. The number of mobile devices also varies with time, and they tend to frequently change their locations. In addition, the available wireless access networks may belong to different domains, administrations, management, and internet service providers (ISPs). A fusion of overlapping heterogeneous wireless access networks (e.g., WiMax, Wi-Fi, LTE, etc.) serves the u-city in order to reach different coverage. In this context, technical challenges arise in mobility management for heterogeneous networks to realize their potential coverage and capacity benefits. This paper deals with the analysis of a decentralized mobility management support for u-City wireless network infrastructure. This scheme takes advantage of the features of the fully-distributed model of networked-based mobility management protocol to alleviate and realize the ubiquitous requirements of a u-City.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.526-534
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• 2014

In this paper, for the WiMedia Distributed Medium Access Control (D-MAC) protocol based on UWB. performance degradation due to the Distributed Reservation Protocol (DRP) conflict problem caused by devices' mobility is analyzed. And a DRP relay protocol and a DRP conflict resolution (CR) are proposed to overcome the performance degradation at DRP conflicts. In order to give the loser device at DRP conflicts a chance to maintain resources, the proposed DRP relay protocol executed at each device helps the loser device reserve an indirect link maintaining the required resources via a relay node. Simulation results considering the mobile environment have indicated that the DRP relay combined with the CR prevent the throughput decrease even though mobility of devices increases.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.10
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• pp.1862-1872
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• 2017

To overcome the limitations of the current Central Mobility Management (CMM) protocols, IETF has been discussing about the Distributed Mobility Management (DMM) protocols that the centralized mobility functions of Home Agents (HA) are distributed to network edges closer to mobile users. The DMM protocol has some advantages of low-cost traffic delivery and high scalability. However, it faces several problems such as a high signaling cost and a complex address management. Especially, users moving at a high speed and with long-live sessions can make these problems worse. To reduce the high signaling cost for long-live sessions, we propose a novel hybrid DMM protocol allocating different mobility anchors according to the session durations. In this paper, we analyze the performance of the proposed hybrid DMM protocol and show superior performance with respect to the signaling cost.

• Journal of Digital Contents Society
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• v.17 no.3
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• pp.111-118
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• 2016

Proxy mobile IPv6 (PMIPv6), which is a centralized mobility management protocol, are dependent on a local mobility anchor (LMA) to process all control and data traffics. Therefore, it has serious problems such as the tremendous traffic concentration into the core network and the triangle routing. In this paper, therefore, in order to alleviate these drawbacks, we propose a PMIPv6-based enhanced distributed mobility management scheme considering a user's traffic locality. Performance evaluation results indicate that in most cases, except for when a user's mobility rate is relatively very higher than the traffic rate, the proposed scheme shows better performance result than that of PMIPv6. Besides, it is demonstrated that the proposed scheme can be an effective alternative that can distribute the significant loads on the LMA of the core networks to the MAGs of the edge networks.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.654-666
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• 2019

The tactical network has several different characteristics compared with commercial internet network such as hierarchical topology, dynamic topology changing and wireless link based connectivity. For considering IP mobility management in the tactical network, current mobility management using Mobile IP(MIP) is not suitable with some reasons such as non-optimal routing paths and single point of failure. Proxy Mobile IP(PMIP) which supporting network-based mobility in hierarchical manner can provide optimal routing path in the tactical network environment, but centralized anchor is still remained a threat to the stability of the tactical network which changes its topology dynamically. In this paper, we propose PMIP-based distributed mobility management for the tactical network environment. From our design, routing paths are always configured in optimized way, as well as path is recovered quickly when the mobility anchor of user is failed. From numerical analysis, comparing to other mobility scheme, result shows that the proposed scheme can reduce packet transmission cost and latency in tactical network model.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1212-1220
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• 2012

In this paper, a collision-free resource reservation scheme for WUSB (Wireless Universal Serial Bus) networks with WiMedia D-MAC (Distributed Medium Access Control). Since distributed characteristic of the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme may cause lots of conflicts, overall performances of the WUSB with WiMedia D-MAC can be deteriorated. In addition, when we consider multi-hop environment, "mobile" hidden node problem due to mobility of WUSB devices can be happened, and it is a critical problem to mobile WUSB devices transceiving real-time QoS (Quality of Service) traffic. To tackle the problem, we propose a new DRP reservation mechanism to prevent DRP conflicts for multi-hop mobility support in WUSB networks with WiMedia D-MAC and show its improved performance via simulation results.