Showing papers by "Hyun-Jeong Kang published in 2004"

Apparatus and method for controlling operational states of medium access control layer in a broadband wireless access communication system

Abstract: Disclosed is a method for controlling an operational state of a medium access control layer in a broadband wireless access communication system. The method includes the steps of performing an uplink access of a contention-based scheme to an access point using resources required to perform the uplink access according to the contention-based scheme when data to be transmitted in an access state is detected, and being allocated resources required to perform an uplink access of a contention-free scheme from the access point in a case of failing in the uplink access of the contention-based scheme; and performing a state transition from the access state into the traffic state in a case of having been allocated the resource required for the contention-free scheme, and performing the uplink access of the contention-free scheme to the access point using the allocated resource in the traffic state.

Method for compulsorily performing handover in broadband wireless communication system

Abstract: Disclosed is a method for enabling a mobile station existing in a serving cell area to perform a handover procedure in a broadband mobile communication system including the mobile station, a serving base station providing a service to the mobile station, and one or more target base stations containing at least one target cell area overlapping with the serving cell area occupied by the serving base station. The method includes transmitting a handover request message from the mobile station to the serving base station when it is detected that a performance of a handover is necessary; and transmitting a handover indication message containing handover cancel information to the serving base station when the mobile station determines a cancel of the handover while the mobile station is being handed over to one or more target base stations by the serving base station.

System and method for dynamically allocating resources in a mobile communication system employing orthogonal frequency division multiple access

Abstract: Dynamically allocating a frame cell (FC)/subchannel in a mobile communication system by an access point that receives channel quality information (CQIs) fed back from access terminals, determines a modulation and coding scheme (MCS) to be applied to the access terminals based on the CQIs, and if access terminals whose FCs/subchannels must be changed are detected from the access terminals, sends an FC/subchannel change request to an access router. The access router allocates an FC/subchannel set by selecting a number of FCs/subchannels according to the FC/subchannel change request, and transmits information on the allocated FC/subchannel set to the access point. The access point selects and allocates a particular FC/subchannel from among FCs/subchannels in the FC/subchannel set information to the access terminals whose FCs/subchannels must be changed, based on CQIs last received from the access terminals.

Method for uplink bandwidth request and allocation based on a quality of service class in a broadband wireless access communication system

Abstract: A bandwidth allocation method for an uplink data transmission between a mobile subscriber station and a base station in a broadband wireless access communication system. The method includes inserting type information of a service requested by the mobile subscriber station into the access channel signal and transmitting the access channel signal to the base station, receiving uplink scheduling information according to the type of the service requested by the mobile subscriber station from the base station, and transmitting data using a transmission bandwidth allocated according to the uplink scheduling information.

Method for a fast state transition from a sleep mode to an awake mode in a broadband wireless access communication system

Abstract: A method for mode transition of a subscriber station between a sleep mode and an awake mode in a broadband wireless access communication system including a base station and at least the subscriber station, the subscriber station having data to transmit in the awake mode and not having data to transmit in the sleep mode is disclosed. The method includes receiving a dedicated orthogonal code from the base station and transiting into the sleep mode in the awake mode, the dedicated orthogonal code being allocated exclusively to the subscriber station; and in the sleep mode, transmitting a message to the base station by means of the dedicated orthogonal code in order to transit into the awake mode.

Mode transition method considering handover in a broadband wireless access communication system

Abstract: Disclosed is a method for enabling a subscriber station to shift from a sleep mode to an awake mode in a broadband wireless access communication system including the sleep mode in which there exists no data to be transmitted between the subscriber station and a base station, and the awake mode in which there exists data to be exchanged between the subscriber station and the base station. The method includes measuring a Carrier-to-Interference and Noise Ratio(CINR) with respect to the base station in a time interval for monitoring a received signal during the sleep mode; and shifting from the sleep mode to the awake mode when the measured signal-to-noise ratio is less than a first threshold value set in advance.

System and method for selecting a serving base station according to a drop of a mobile subscriber station in a broadband wireless access communication system

Abstract: Disclosed are a system and a method for selecting a new serving base station when a drop occurs in a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station, a serving base station communicating with the mobile subscriber station, and a plurality of neighbor base stations, different from the serving base station. The mobile subscriber station receives information related to the neighbor base stations from the serving base station communicating with the mobile subscriber station. The mobile subscriber station monitors the frequency bands of the neighbor base stations included in the information related to the neighbor base stations if the drop is detected in order to detect target base stations capable of serving as a new serving base station for communicating with the mobile subscriber station when the drop occurs in the mobile subscriber station according to a monitoring result for the frequency bands of the neighbor base stations. The mobile subscriber station selects the new serving base station from the detected target base stations so that the it is possible for the mobile subscriber station to reestablish the communication with regard to the new serving base station within a short period of time.

Route discovery device and method in a mobile ad-hoc network

Abstract: A route discovery device and method in a mobile ad-hoc network. The route discovery device and method seamlessly maintain a route for providing service by establishing the service route while taking into account the efficiency of energy of a terminal in the mobile ad-hoc network. A mobile host broadcasts a service request message. One of relay hosts of the mobile hosts selects a service request message, calculates power information of the mobile host, includes the calculated power information of the mobile host in the power information included in the selected service request message and re-broadcast the service request message. A destination host of the mobile hosts selects a service request message, generates a service response message and transmits the service response message along a route of the selected message.

Method for performing uplink access in broadband mobile communication system

Abstract: Disclosed is an efficient random access method which enables a subscriber station to gain access to an uplink in broadband mobile communication system including the subscriber station and a base station. The method enables a subscriber station to perform re-access to a base station at a high speed in the mobile communication system, in which an access channel is allocated so that the subscriber station and the base station can transmit a message to each other using a code within a predetermined period of time, wherein, the method includes the steps of: the subscriber station receiving a request rejection message including a dedicated code in response to a request message transmitted from the subscriber station to the base station through the access channel; and the subscriber station checking the received request rejection message, and re-transmitting the request message in a contention-free method corresponding to the dedicated code which is included in the request rejection message.

System and method for dynamic channel allocation in a communication system using an orthogonal frequency division multiple access network

Abstract: A system and method for dynamically allocating channels in a wireless communication system including multiple sub-channels and multiple frame cells, each of the sub-channels being an assembly including a preset number of sub-frequency bands divided from an overall frequency band, the frame cells using each of the sub-channels as a basic transmission unit and having a frequency domain and a time domain occupied by the sub-channels. A mobile station transmits channel quality information of frame cells to an access point. An access router transmits channel allocation information about the multiple frame cells and sub-channels determined according to the received channel quality information to the access point, and the access point receives the channel allocation information about the multiple frame cells and sub-channels, compares the channel allocation information with newest channel quality information, and allocates a sub-channel of a frame cell selected according to the comparison to the mobile station.

Mobile IP communication system using dual stack transition mechanism and method thereof

Abstract: A system and method for assigning and managing a mobile IP in an access node for communicating with a mobile node supporting IP version 6 (IPv6) technology, assigning an IPv6 address to the mobile node, and using a dual stack transition mechanism capable of providing an IP version 4 (IPv4) address upon receiving an IPv4 address request from the mobile node, and a border router for interfacing between an IPv4 native network and an IPv6 native network.

Method and system for generating ip addresses of access terminals and transmitting messages for generation of ip addresses in an ip system

Abstract: A system for transmitting a message for generating an Internet Protocol version 6 (IPv6) address is provided. The system includes at least one access terminal, an access point, and a router. The access terminal transmits a first medium access control (MAC) layer connection message including its own MAC address and a fast address setup indication field to the access point. The access point receives the first MAC layer connection message from the access terminal, and determines whether a duplicate MAC address of the MAC address of the access terminal exists in the same sub-network.

Apparatus and method for transmitting wakeup channel for mode transition in sleeping state in a broadband wireless communication system

Abstract: A method and apparatus for transmitting a DL-WUCH for a mode transition in a sleeping state in a broadband wireless communication system are provided. In the broadband wireless communication system, a base station (BS) transmits control information to a plurality of subscriber stations (SSs) on a common control channel. To demodulate a control channel signal received from the BS, an SS receives a wakeup channel signal which indicates whether the control channel signal includes control information for the SS, reads a wakeup channel indicator at a predetermined position assigned to the SS of the wakeup channel signal, and determines whether to demodulate the control channel signal according to the wakeup channel indicator.

A Unified Route Optimization Scheme for Network Mobility

Abstract: Recently Network Mobility(NEMO) is being concerned as new mobility issue. Lots of NEMO issues are already being touched in IETF NEMO WG but the solution is still premature especially to the Route Optimization (RO). NEMO has several problem spaces that need RO such as nested tunnels problem. Unfortunately, there is no solution that can be universally applied as one for all that results in supporting the coherent network mobility. In this paper, we propose a unified route optimization scheme that can solve several types of RO problem by using Path Control Header (PCH). In our scheme, Home Agent (HA) does piggyback the PCH on the packet which is reversely forwarded from Mobile Router (MR). That enables any PCH-aware routing facility on the route to make a RO tunnel with MR using the Care-of address of MR contained in the PCH. By applying to some already known NEMO RO problems, we show that our scheme can incrementally optimize the routes via default HA-MR tunnel through the simple PCH interpretation.

Method and system for fast call recovery in a broadband wireless access communication system

Abstract: Disclosed are a system and a method for selecting a new serving base station when a drop occurs in a mobile subscriber station in a broadband wireless access communication system. The mobile subscriber station receives information related to a plurality of neighbor base stations from a serving base station communicating with the mobile subscriber station. The mobile subscriber station monitors the frequency bands of the neighbor base stations included in the information related to the neighbor base stations if the drop is detected in order to detect target base stations capable of serving as a new serving base station for communicating with the mobile subscriber station when the drop occurs in the mobile subscriber station according to a monitoring result for the frequency bands of the neighbor base stations. The mobile subscriber station selects the new serving base station from the detected target base stations so that the it is possible for the mobile subscriber station to reestablish the communication with regard to the new serving base station within a short period of time.

Method for optimizing nested tunnels using nested path information in a mobile network

Abstract: A method for optimizing a tunnel between a second mobile router and a home agent of the second mobile router in a mobile network having a nested structure in which a first mobile router manages a subnetwork including at least the second mobile router. The second mobile router manages a subnetwork including at least one node. The second mobile router receives nested path information from the first mobile router. The second mobile router transmits the nested path information to the home agent of the second mobile router via the first mobile router. The home agent of the second mobile router stores the nested path information received from the second mobile router thereby performing tunneling with the second mobile router.

System and method for selecting a serving base station in a broadband wireless access communication system

Abstract: Disclosed are a system and a method for selecting a new serving base station when a drop occurs in a mobile subscriber station in a broadband wireless access communication system. The mobile subscriber station receives information related to a plurality of neighbor base stations from a serving base station communicating with the mobile subscriber station. The mobile subscriber station monitors the frequency bands of the neighbor base stations included in the information related to the neighbor base stations if the drop is detected in order to detect target base stations capable of serving as a new serving base station for communicating with the mobile subscriber station when the drop occurs in the mobile subscriber station according to a monitoring result for the frequency bands of the neighbor base stations. The mobile subscriber station selects the new serving base station from the detected target base stations so that the it is possible for the mobile subscriber station to reestablish the communication with regard to the new serving base station within a short period of time.

Procede et systeme permettant de generer des adresses ip de terminaux d'acces et de transmettre des messages destines a la generation d'adresses ip dans un systeme ip

Abstract: La presente invention concerne un systeme permettant de transmettre un message destine a generer une adresse version six Internet Protocole (IPv6). Ce systeme comprend au moins un terminal d'acces, un point d'acces et un routeur. Le terminal d'acces transmet un premier message de connexion de couche de controle d'acces au support (MAC) comprenant sa propre adresse MAC et un champ d'indication d'installation d'adresse rapide vers le point acces. Ce point d'acces recoit le premier message de connexion de couches MAC du terminal d'acces et determine si un double d'adresse MAC de l'adresse MAC du terminal d'acces existe dans le meme sous reseau.

Systeme de communication ip mobile utilisant un mecanisme de transition a double pile et procede connexe

Abstract: L'invention concerne un systeme et un procede d'attribution et de gestion d'un IP mobile dans un noeud d'acces en vue de la communication avec un noeud mobile prenant en charge la version 6 IP (IPv6), d'attribution une adresse Ipv6 au noeud mobile et d'utilisation un mecanisme de transition a double pile apte a fournir une adresse de version 4 IP (IPv4) apres reception d'une demande d'adresse IPv4 a partir du noeud mobile et un routeur de limite en vue de l'interfacage entre un reseau natif Ipv4 et un reseau natif Ipv6.