Electronics and Telecommunications Research Institute

Korea Telecommunication Authority

Future Wei Technologies, Inc.

Information & Communications University

Hyeong Ho Lee

Tae Whan Yoo

Byoung Whi Kim

Hae Won Jung

Heyung Sub Lee

Jae Woo Yang

Tae Il Kim

Chan Soo Kim

Ho Yong Kang

Sung Soo Kang

Hyunho Park

Hoon Ki Lee

Seung Keun Park

Seung Hwan Kim

Sang Gug Lee

Hyun Kyun Choi

Jae Doo Huh

Jin A Park

Jae Dong Park

Sungsoo Kang

Jung Sik Sung

Ho Sook Lee

Man Seop Lee

Pyung Dong Cho

Ja Won Seo

Su Il Choi

Young Ki Lee

Do Yeon Kim

Jun Hwa Lee

Jin Young Choi

Young Sun Kim

Sang Min Lee

Ju Young Park

Kang Bok Lee

Cheon Soo Kim

Hinghung Anthony Chan

Il Woo Lee

Tae Yeon Kim

Bong Kyu Kim

Jeong Ju Yoo

Eui Suk Jung

Mi Jeong Yang

Young Seob Cho

Bin Yeong Yoon

Jea Hoon Yu

Hong Soon Nam

Junghak Kim

Bong Wan Kim

Hyoung Jun Kim

Chang Ho Choi

Hyun Ha Hong

Bheom Soon Joo

Daeub Kim

Chung Kook Lee

Jun Seob Lee

Dae Young Kim

Woo Seop Rhee

Hyun Ho Yun

Yong Woon Kim

Jung Hoon Jee

Tae Ii Kim

Jung Whan Kim

Sang Ha Kim

Tae-Il Kim

Hyeon Ho Yoon

Sang Keun Yoo

Younghee Yeon

Sangjo Park

Kang Woon Hong

Seung-eui Jin

Hong Seock Jeon

Je I Back

Changoo Lee

Mun G Kyong

Hang G Park

Deok H Kim

Keun K Lee

Seon M Hong

Yong B Kim

Go B Choi

Dae Up Kim

Jong Hwa Yi

Yongtae Kim

An apparatus, system and method for managing radio resources are disclosed. The apparatus for managing radio resources includes a media independent services (MIS) user unit, a link layer unit, and a media independent services function (MISF) unit. The link layer unit outputs its own link status and radio resource allocation status. The MISF unit receives a report on the link status and radio resource allocation status from the link layer unit, receives a report on link status of a terminal from the corresponding terminal, receives a report on link status and radio resource allocation status of a neighboring Point of Attachment (PoA) from the corresponding neighboring PoA, and receives network configuration information from a network configuration information server. The MIS user unit determines to change radio resource allocation based on information from any one of the link layer unit, the terminal, the neighboring PoA and the network configuration information server.

Apparatus, system and method for controlling radio resources

The present invention relates to a method of providing proximity service communication between terminals. In accordance with an embodiment, a first terminal makes connection to a second terminal with network assistance. The first terminal requests information required to search for the second terminal from a network management server. The network management server determines a communication mode for proximity service communication. The network management server transmits a request message requesting communication between the first terminal and the second terminal in the communication mode to the first and second terminals. In accordance with another embodiment, a first terminal may switch its proximity service communication technology for better QoS without network assistance. The first terminal monitors link status. If the link status is deteriorated, the first terminal requests a second terminal to change proximity service communication technology. The first and the second terminal switch their proximity service communication technologies.

Method of providing proximity service communication between terminals supporting proximity service communications

Single radio handovers (SRHOs) between heterogonous networks can be facilitated using several techniques. One such technique includes activating a receiver of a target radio interface in a mobile node without activating a transmitter of the target radio interface, thereby allowing the mobile node to perform target network discovery while the transmitter of the target radio interface remains deactivated. Another such technique includes encapsulating link-layer discovery frames into media independent handover frames (MIH), and then tunneling the MIH frames over a tunnel extending through the source network. This may allow the MN to achieve various handover related tasks without activating the target radio link. Another technique includes establishing a schedule (or delay period) for synchronizing deactivation of the source radio interface with activation of the transmitter in the target radio interface.

System and method for single radio handover

Provided is a fast handover method using candidate care-of addresses (CoAs). The method includes obtaining Internet protocol (IP) address information of access routers located adjacent to a previous access router (PAR) to which a mobile node is connected; setting more than one candidate CoAs based on the IP address information; and selecting from the more than one candidate CoAs a CoA of a sub-net to which the mobile node is to move and performing a handover based on the selected CoA. Therefore, a delay and a packet loss caused by the setting of a new NCoAs can be prevented.

Fast handover method using candidate CoAs

An apparatus and method for improving a symbol error rate of an M-ary phase shift keying (M-PSK) system having a quadrature error are provided. The apparatus includes: a conversion parameter detector that detects a conversion parameter and converts a symbol decision region using the quadrature error and at least one pair of first received symbols; and a converter & determiner converting a pair of second received symbols using the detected conversion parameter, and determining a transmission symbol according to a symbol of the converted pair of second received symbols. An increase in a symbol error rate due to the quadrature error can be prevented and the quadrature error can be easily estimated.

Apparatus and method for improving symbol error rate performance of M-ary phase shift keying system having quadrature error

Provided is an apparatus and method for preventing air baggage from getting lost using a radio frequency identification (RFID) system. The apparatus for preventing baggage from getting lost, change, or stolen in which a baggage tag storing baggage management information is attached to the baggage and a receipt tag storing the baggage management information is issued to a baggage owner, the apparatus includes: a tag reader reading the receipt tag and the baggage tag in a predetermined area; and a determiner determining whether the tag reader reads the receipt tag including the same baggage management information as the baggage management information of the baggage tag within a predetermined time before and after the tag reader reads the baggage tag. As a result, air baggage is quickly and exactly managed, costs is reduced, and foreign confidence of an airport is increased, thereby preventing baggage from getting lost and exchanged.

Apparatus and method for preventing loss of baggage using RFID

An apparatus for and method of deciding symbols in a M-ary phase shift keying (MPSK) system are provided. The apparatus includes: a linear transform unit performing linear transform, to which a phase error is applied, of a received pair of symbols; and a symbol decision unit deciding a transmitted symbol corresponding to the received pair of symbols according to the sign value of the transformed symbol pair. According to the apparatus and method, degradation of a symbol error rate caused by a phase error when an MPSK signal is demodulated can be improved and a phase error can be estimated through a simple method.

Apparatus and method of deciding received symbol in M-PSK system

Disclosed herein is a shared Local Area Network (LAN) emulation method and apparatus. The method includes the following four steps. At the first step, a Logical Link Identifier (LLID) management table is set up to assign unique LLIDs to a plurality of Optical Network Units (ONUs) and manage the assigned LLIDs so as to identify the plurality of ONUs connected to a single Optical Line Terminal (OLT). Thereafter, a MAC address table is set up for the LLIDs to learn MAC addresses of the ONUs. Thereafter, the unique LLIDs are assigned to ONUs when the ONUs request registration from the OLT. Finally, data frames, which are received by a Shared LAN Emulation (SLE) layer of the OLT, are bridged using the LLIDs, VIDs of Virtual LANs to which the ONUs belong and destination MAC addresses of the data frames so as to provide a single matched port between a Logical Link Control (LLC) layer and a MAC layer of the OLT.

Shared LAN emulation method and apparatus having VLAN recognition and LLID management functions on EPON

Provided is a digital broadcast system that receives digital broadcast services on a passive optical network (PON). The data separator separates a signal input thereinto from the outside into an Ethernet frame for data service and an Ethernet frame for digital broadcast service. The Ethernet switch transmits the Ethernet frame for data service to an optical network terminal (ONT) provided in the user's home according to header information of the Ethernet frame for data service. The channel request processor receives the user's channel selection request information and user identification (ID) information from the ONT. The digital broadcast processor transmits the Ethernet frame for digital broadcast service, corresponding to the digital broadcast channel selected by the user, to the user's ONT, by using a part of bandwidth assigned for an existing line.

Digital broadcast system in passive optical network

An Ethernet switch having a function of expanding a port, apparatus and method for expanding a port are provided. A receiver receives a frame including predetermined port identification information. An information detector detects the predetermined port identification information and a terminal address of a terminal connected to a sub port corresponding to the predetermined port identification information. A storage unit stores an address table including the terminal address and the predetermined port identification information. A reader reads port identification information corresponding to a destination address included in the frame from the address table. A frame transformer adds the read port identification information to the frame. An output unit outputs the frame transformed by the frame transformer to a main port connected to a sub port corresponding to the read port identification information among main ports that can be connected to at least one sub port.

Ethernet switch, and apparatus and method for expanding port

A method of controlling a Forward Error Correction (FEC) operation including: configuring a FEC frame to be transmitted between an OLT and an ONU comprising a FEC frame identifier indicating whether FEC should be performed, data, a first flag indicating that FEC should be performed, and a second flag indicating that the FEC frame is to be FEC encoded; initializing the OLT by disabling a FEC function; determining whether the ONU requires FEC to be performed based on a FEC frame identifier received from the ONU; IPG stretching the FEC frame when the ONU requires to FEC to be performed; and transmitting the FEC frame to the ONU after FEC encoding based on the second flag of an input frame to a PCS sublayer from an upper layer. The method controls an effective operation of a FEC of an ONU and an OLT without changing a Round Trip Time (RTT) according to optical link quality in an EPON. Accordingly, FEC is used only if necessary, thereby simplifying the managing of a link, and preventing an excessive 35% reduction of throughput caused by use of unnecessary FEC.

Method of controlling FEC in EPON

A PLC-based wavelength-tunable WDM-PON system with an optical wavelength alignment function, the WDM-PON system comprises: a PLC platform formed on a silicon substrate; a semiconductor chip comprising an active region generating light and a passive region located in front of the active region for vertically coupling the light generated in the active region; a planar lightwave circuit (PLC) waveguide; one portion of a PLC platform where the semiconductor chip is surface mounted; waveguide Bragg grating (WBG) formed at a predetermined location of the PLC waveguide; a directional coupler transferring an optical power by permitting the passive region to approach the PLC waveguide; a heater terminal, which is formed on the WBG; and a V-groove for attaching an optical fiber to another end of the PLC waveguide. Accordingly, a WDM-PON system having a function of realizing a cost-effective optical wavelength alignment can be provided.

WDM-PON system with optical wavelength alignment function

An apparatus for transmitting a FEC frame is provided. In order to correct an error caused by a transmission medium using FEC in a Reed-Solomon code type, FEC encoding/decoding of a frame is performed. A total transmission delay time is not influenced when FEC is bypassed, a delay caused by a shortened codeword is minimized, and a FEC encoding/decoding delays for frames having different lengths are equalized.

Apparatus for FEC supporting transmission of variable-length frames in TDMA system and method of using the same

Provided is a burst mode optical receiver capable of accurately detecting an optical signal of minimum amplitude, by automatically controlling a gain of a pre-amplifier according to an amplitude of an input optical signal. The burst mode optical receiver can automatically control a gain of a pre-amplifier according to the amplitude of an input optical signal using an output signal of a first peak detector. In other words, when the input optical signal has a small amplitude that meets the receiving sensitivity of the burst mode optical receiver, the gain of the pre-amplifier automatically increases, thereby improving the receiving sensitivity of the burst mode optical receiver.

Burst mode optical receiver for maintaining constant signal amplitude

Disclosed is a loop-back optical network terminal using a Febry-Perot laser diode as an active type optical modulator in a wavelength division multiplexing based optical network. In addition, a wavelength division multiplexing based optical network having the same is disclosed. The optical network terminal comprises a modulation timing control signal generator receiving a downstream optical signal transmitted from a central office and generating a timing control signal designating a start timing and an end timing for modulating an upstream optical signal to be transmitted from a user to the central office; an upstream data control circuit generating upstream data according to the timing control signal and controlling modulation of the upstream optical signal according to the timing control signal in response to generation of the upstream data; and a modulator receiving the upstream data and directly modulating the upstream data with loop-backing the downstream optical signal to produce the upstream optical signal and then output it to the central office.

Optical network terminal and wavelength division multiplexing based optical network having the same

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Daejeon, South Korea

Hyeong Ho Lee