scispace - formally typeset
Search or ask a question
Author

Nam-Hoon Park

Bio: Nam-Hoon Park is an academic researcher from Electronics and Telecommunications Research Institute. The author has contributed to research in topics: Hybrid automatic repeat request & Femtocell. The author has an hindex of 16, co-authored 69 publications receiving 772 citations.

Papers published on a yearly basis

Papers
More filters
Proceedings ArticleDOI
26 Sep 2004
TL;DR: The paper investigates the queueing behavior of the sleep mode operation in IEEE 802.16e for conserving the power of an mobile station (MS) in terms of the dropping probability and the mean waiting times of packets in the base station (BS) queue.
Abstract: The paper investigates the queueing behavior of the sleep mode operation in IEEE 802.16e for conserving the power of an mobile station (MS) in terms of the dropping probability and the mean waiting times of packets in the base station (BS) queue. In the sleep mode, when an MS wakes up at the end of each sleep interval and there is traffic addressed to it, this is notified in the listening interval immediately following the sleep interval. Otherwise, an MS again enters the sleep mode with a sleep interval which is double the length of the previous one. We modeled this sleep mode operation as M/GI/1/N with multiple vacations whose periods depend on the previous one. Our work may be a rough guide to understanding the BS queueing behavior according to parameters such as the minimum and maximum sleep interval, the BS queue size and the arrival rate of packets at a BS.

112 citations

Patent
27 Dec 2002
TL;DR: In this paper, a communication device that automatically searches for wireless local area network (WLAN) access points, and to a method thereof, is presented, where the searching of the WLAN access points is performed automatically without the need for user manipulation.
Abstract: The present invention relates to a communication device that automatically searches for wireless local area network (WLAN) access points, and to a method thereof. The communication device includes a GPS receiving module (12) for receiving position information of the connection device from a GPS satellite; a WLAN module (11) for connecting with the WLAN access point; a storage unit (13) for storing position information of the WLAN access point; and a controller (14) for selectively operating the WLAN module based on the position information of the communication device output from the GPS receiving module (12) and the position information of the WLAN access point stored in the storage unit (13). According to the present invention, a user terminal receiving data services through WLAN efficiently utilizes power. Also, the searching of the WLAN access points is performed automatically without the need for user manipulation.

59 citations

Proceedings ArticleDOI
18 Nov 2011
TL;DR: In this article, the femtocells are deployed in the vehicular environment to solve the low-level signal-to-noise plus interference problem in vehicular environments and the capacity and the outage probability are analyzed.
Abstract: The femto-access-point (FAP), a low power small cellular base station provides better signal quality for the indoor users. The mobile users in the vehicular environment suffer for the low quality signal from the outside wireless networks. The deployment of femtocells in the vehicular environment can solve the low level signal-to-noise plus interference problem. In this paper, we propose new application of the femtocell technology. The femtocells are deployed in the vehicular environment. Short distance between the user and the FAP provides better signal quality. The inside FAPs are connected to the core network through the outside macrocellular networks or the satellite networks. One stronger transceiver is installed at outside the vehicle. This transceiver is connected to FAPs using wired connection and to macrocellular or the satellite access networks through wireless link. The capacity and the outage probability are analyzed. The simulation results show that the proposed mobile femtocell deployment significantly enhances the service quality of mobile users in the vehicular environment.

44 citations

Patent
30 Sep 2004
TL;DR: In this article, a system and method for transmitting/receiving an ARQ for correcting errors in an OFDM/TDMA terminal, and generating high-rate frames is presented.
Abstract: Disclosed are a system and method for transmitting/receiving an ARQ for correcting errors in an OFDM/TDMA terminal, and generating high-rate frames. The ARQ transmitting/receiving system of an OFDM/TDMA terminal comprises a CPU transmitting/receiving a data packet to/from an upper block in a software manner; an ARQ transmitting/receiving unit receiving the data packet, dividing the data packet into fragments each having a predetermined size, storing the fragments, generating a frame at the moment of generating a frame based on the stored fragment information, checking whether ARQ is retried or not, and transmitting/receiving the ARQ in a hardware manner; an interface buffer storing data transmitted between the CPU and the ARQ transmitting/receiving unit; and a fragment buffer storing fragments generated by the ARQ transmitting/receiving unit.

43 citations

Patent
02 Dec 2009
TL;DR: In this article, when a receive signal strength received from a target network that will perform the handoff is larger than a reference strength, software related to the target network is previously installed in the corresponding portable terminal.
Abstract: When a receive signal strength received from a target network that will perform the handoff is larger than a reference strength, software related to the target network is previously installed in the corresponding portable terminal, a wireless connection environment with the target network is configured by driving the software related to the target network at the time of determining that the handoff is performed, and performs the handoff to the target network in the portable terminal.

41 citations


Cited by
More filters
Patent
Jong Hwan Kim1
13 Mar 2015
TL;DR: In this article, a mobile terminal including a body; a touchscreen provided to a front and extending to side of the body and configured to display content; and a controller configured to detect one side of a body when it comes into contact with a side of an external terminal, display a first area on the touchscreen corresponding to a contact area of body and the external terminal and a second area including the content.
Abstract: A mobile terminal including a body; a touchscreen provided to a front and extending to side of the body and configured to display content; and a controller configured to detect one side of the body comes into contact with one side of an external terminal, display a first area on the touchscreen corresponding to a contact area of the body and the external terminal and a second area including the content, receive an input of moving the content displayed in the second area to the first area, display the content in the first area, and share the content in the first area with the external terminal.

1,441 citations

Journal ArticleDOI
TL;DR: This paper presents the key features and the driver technologies of IoT, and identifies the application scenarios and the correspondent potential applications, and focuses on research challenges and open issues to be faced for the IoT realization in the real world.

1,178 citations

Patent
04 Jun 2008
TL;DR: In this article, the demarcation point unit passes data to and receives data from the home electronic device through the home network module, which is adapted for connection to a home electronic devices.
Abstract: A home network, in one embodiment including a home wiring system; a demarcation point unit in electrical communication with the home wiring system; and a home network module in electrical communication with the home wiring system. The home network module is adapted for connection to a home electronic device. The demarcation point unit passes data to and receives data from the home electronic device through the home network module.

398 citations

Proceedings ArticleDOI
Lang long1
16 Aug 2004
TL;DR: It is shown that there exists a threshold on sensor outage probability above which a distributed random access protocol (such as ALOHA) outperforms the centralized deterministic schedulers.
Abstract: Summary form only given. The layered architecture is one of the key reasons behind the explosive and continuing growth of the Internet. There are, however, special networks in which cross-layer design is appropriate and may even be necessary. Two such cases are small wireless LAN and large-scale sensor networks. We consider first the design of medium access control (MAC) for a small wireless LAN based on a multiuser physical layer. We present a complete characterization of the throughput region and present conditions under which ALOHA is optimal. Next we consider the estimation of signal field using data collected from a large scale sensor network. The impact of medium access control on estimation is examined. We show that there exists a threshold on sensor outage probability above which a distributed random access protocol (such as ALOHA) outperforms the centralized deterministic schedulers.

335 citations

Journal ArticleDOI
TL;DR: A survey of the existing methodologies related to aspects such as interference management, network discovery, proximity services, and network security in D2D networks is presented and new dimensions with regard to D1D communication are introduced.
Abstract: The increasing number of mobile users has given impetus to the demand for high data rate proximity services. The fifth-generation (5G) wireless systems promise to improve the existing technology according to the future demands and provide a road map for reliable and resource-efficient solutions. Device-to-device (D2D) communication has been envisioned as an allied technology of 5G wireless systems for providing services that include live data and video sharing. A D2D communication technique opens new horizons of device-centric communications, i.e., exploiting direct D2D links instead of relying solely on cellular links. Offloading traffic from traditional network-centric entities to D2D network enables low computational complexity at the base station besides increasing the network capacity. However, there are several challenges associated with D2D communication. In this paper, we present a survey of the existing methodologies related to aspects such as interference management, network discovery, proximity services, and network security in D2D networks. We conclude by introducing new dimensions with regard to D2D communication and delineate aspects that require further research.

275 citations