Abstract: Disclosed is a demodulation apparatus for receiving signals by an adaptive modulation and coding method, and demodulating the signals, in an OFDMA based packet communication system, comprising: a QAM demapper for performing QAM demapping to the received signals by a modulation method using a maximum modulation ratio, until modulation methods for each of sub-channels are analyzed; a slot buffer for storing the data outputted from the QAM demapper; a channel decoder for decoding the data stored in the slot buffer and analyzing modulation methods for each sub-channels and transferring the analyzed modulation methods to the QAM demapper; and in at the same time, reading valid data from the data stored in the slot buffer, based on the analyzed modulation methods for each sub-channels, and demodulating the valid data.

Abstract: The present invention relates to a vertical handoff method. According to the present invention, a serving network of a mobile station is determined. Herein, the mobile station that can access a first network having relatively wide service coverage and a second network having relatively narrow service coverage in an area where service coverages of heterogeneous networks are overlapped. When accessing the serving network of the first network, it is determined whether a received signal strength received from the second network is greater than a first threshold value. In addition, a first vertical handoff is decided by using a result of prediction of a transition pattern of the received signal strength that is greater than the first threshold value. When the serving network is the second network, it is determined whether the received signal strength received from the second network is less than a second threshold value.

Abstract: A method for automatically optimizing a neighbor list for processing handover in an asynchronous WCDMA (Wide-band Code Division Multiple Access) network includes the steps of: collecting neighbor list data, call fault data, handover statistical data, base station location data and PSC information data of each base station sub-cell (or, sector) in a nationwide network; extracting all target sub-cells (or, sectors) available for handover by analyzing the collected data; endowing a weighting factor to the extracted target sub-cells (or, sectors) according to importance and then sorting calculated results so as to determine priorities; and subsequently inputting the target sub-cell (or, sector) information to the neighbor list according to the priorities.

Abstract: A method for automatically optimizing a neighbor list for processing handover in a synchronous CDMA (Code Division Multiple Access) network includes the steps of: collecting neighbor list data, call fault data, handover statistical data, base station location data and PN information data of each base station sector in a nationwide network; extracting all target sectors available for handover by analyzing the collected data; endowing a weighting factor to the extracted target sectors according to importance and then sorting the target sectors according to calculated results so as to determine priorities; and subsequently inputting the target sector information to the neighbor list according to the priorities.

Abstract: A ranging method of an access terminal that requests a ranging to an access point through a wireless network and performs the ranging, the ranging method including a) initializing a ranging period, b) setting a timer with the ranging period and starting the timer, c) requesting a ranging by transmitting a given ranging code to the access point based on radio resource allocation information provided by the access point, d) receiving a ranging response message from the access point, and controlling transmission power, timing, and frequency offset of an access terminal according to transmission parameters included in the received ranging response message, e) estimating a downlink channel condition through which a signal from the access point is transmitted, f) resetting the ranging period according to the estimated downlink channel condition, and g) iteratively performing b) to f) according to the reset ranging period.

Abstract: Disclosed are a conditional access transmission system and method, and a receiving terminal and method. The transmission system transmits scrambled broadcasting signals including a network identification code (NIC) in the digital broadcasting service. A repeating system repeats the broadcasting signals transmitted by the transmission system to a subscriber station. In this instance, the NIC of the repeating system is different from that of a main broadcasting network. A receiving terminal descrambles the scrambled broadcasting signals by using the NIC and a descrambling key. According to the present invention, the charged subscriber can receive broadcasting signals or TPEG messages in the repeating network.

Abstract: Disclosed is a system for downloading an application from a server and providing the same to a client by using a short message or a subscriber interface module (SIM) card. The system modifies a function key for each application according to a client's selection, and randomly modifies a user interface used for selecting an application. The system extends a usage range of the SIM card. The system periodically checks and analyzes the client' use log for a predetermined time, presents at least one application to the client according to the analysis result on the use log, provides a single application selected by the client to the client, and updates at least one application stored in the client mobile terminal according to the analysis result on the use log. Therefore, the system increases service satisfaction for the client.

Abstract: Disclosed are an interworking system between IP networks using different IP address format, an application layer gateway (ALG) server, a network address translator, an interworking method, and a SIP message routing method. The interworking system between a local network using a private IP and a public network using a public IP includes a STUN server and an application layer gateway (ALG) server. The STUN server provides binding information of header information of a public IP binding request. The application layer gateway (ALG) server performs a public IP binding request with header information changed by IP masquerading, and performs routing by applying the received binding information to media receiving address information of a SIP message.

Abstract: Disclosed is an apparatus for generating a ranging pseudo noise code used for a terminal of a portable internet system of an OFDM access scheme. The apparatus for generating ranging pseudo noise code detects a cell ID number using a preamble signal transmitted from a base station covering the terminal, detects a ranging pseudo noise code mask value using the detected cell ID number and system parameters input from the base station, and generates a ranging pseudo noise code using the detected cell ID number and the ranging pseudo noise code mask value. With the above structure, a constant initial value can be used irregardless of the cell ID number of the base station, and a desired ranging pseudo noise code can be generated as fast as possible so as to have a desired offset.

Abstract: A recording medium having an internal data structure for uplink data transmission based on QoS in a mobile terminal of an OFDMA/TDMA-based high-speed portable Internet system, the internal data structure comprising a connection identifier index indicating a predetermined connection of the mobile terminal; a service class index indicating QoS classes of uplink data; a control channel index indicating a type of a control channel for transmission of a management message of the mobile terminal; an access type index indicating a type of access for a bandwidth request of the mobile terminal; a user packet list having IP packets linked to each other through a linked list; a management message list having the management messages linked to each other through a linked list; and a bandwidth request list having informative elements that are linked to each other for the bandwidth request through a linked list.

Abstract: The present invention provides an LDPC encoder, a channel encoder of a portable internet system including the LDPC encoder, and an encoding method thereof. The LDPC encoder according to the present invention generates a Costas array, shifts it, generates an analogous circulation parity check matrix having a repeated pattern from the shifted Costas array, and performs encoding by using the parity check matrix. With this LDPC encoder, complexity of encoding system may be reduced.

Abstract: A terminal of a portable Internet system comprising a medium access control (MAC) layer and a physical layer, the MAC layer comprising: a classifier classifying packets into classes; a delayer calling queue operating functions when a predetermined period of time is passed after the packets are classified by the classifier; a wait queue storing packets by the queue operating functions; and a packet processor processing the packet in the wait queue and transmitting the processed packet to the physical layer.

Abstract: Disclosed is a method and device for controlling a power saving mode for applying the sleep mode for saving power consumption to the mobility of subscriber stations in a mobile communication network and a wireless Internet system. Subscriber stations entering the sleep mode are constantly grouped, listening intervals of the subscriber stations for each group are not superimposed, the existence state of traffic in the subscriber stations is independently notified for each group, and the overhead of signaling messages is minimized when the traffic is notified to the subscriber station in the sleep mode.

Abstract: Disclosed is a traffic encryption key (TEK) management method for automatically generating a TEK for a multicast or broadcast service by a base station to periodically update a TEK used by a subscriber station. The base station transmits the first Key Update Command message for updating a group key encryption key (GKEK) for encrypting the TEK and the second Key Update Command message for updating the TEK to the subscriber station to update the TEK. The base station establishes an M & B TEK Grace Time which is different from a TEK Grace Time established by the subscriber station, transmits the first message including a new GKEK to the subscriber station through a primary management connection before the M & B TEK Grace Time, and transmits the second message including a new TEK encrypted with the new GKEK thereto through a broadcast connection after the M & B TEK Grace Time.

Abstract: A mobile station transmitting and receiving method and a corresponding mobile station transmitter and receiver of a smart antenna system for forming uplink eigenbeams of the OFDM/TDD (orthogonal frequency division multiplex/time division duplex), wherein OFDM symbols are received from a base station through a downlink via multiple antennas (250) and an FFT (fast Fourier transform) is performed on the received OFDM symbols by the FFT units (270). By means of a channel estimator (290) the channels are estimated and a beam weight generator (310) generates respective beam weights from the channels of the respective pilot tones of the respective subcarriers according to the channel estimation result. A beam weight multiplier (230) forms the uplink beam by multiplying the respective beam weights with the output of the signal repeater (220) and IFFT units (240) generate respective OFDM symbols which are transmitted via multiple antennas (250) through an uplink.

Abstract: Provided is a method for allocating an Internet protocol (IP) address to a mobile station in a mobile communication system. The method includes the steps of: a) receiving an “Activate Packet Data Protocol (PDP) request” message including router solicitation from the mobile station; b) acquiring a global IP address of the mobile station by performing the router solicitation and a router advertisement procedure instead of the mobile station; and c) loading the acquired global IP address in an “Activate PDP context Accept” message and transferring the “Activate PDP context Accept” message to the mobile station.

Abstract: The present invention relates to a mobile station of an OFDMA system and a transmit power control method thereof. The mobile station includes a modulator, a variable gain amplifier, a gain controller, and a power controller. The modulator modulates transmit data according to the number of allocated subchannels, and the variable gain amplifier amplifies the transmit data. The gain controller controls a gain of the transmit data inputted to the variable gain amplifier according to a subchannel gain value corresponding to the number of subchannels. The power controller calculates a power control gain for controlling power of the transmit data except the subchannel gain value based on the signal received from the base station and outputs the power control gain to the variable gain amplifier.

Abstract: A method for updating a domain name server (DNS) address by obtaining the DNS address when an IP address is allocated by using a mobile IP address in a mobile terminal using the portable interne based on a wireless mobile network is provided. In the method at least one DNS address connected to the wireless mobile network is sampled (S400), a roundtrip delay to the respective sampled DNSs is calculated (S450), a DNS address having a minimum roundtrip delay is selected (S460), and a DNS address of the mobile terminal is updated to be the selected DNS address (S500).

Abstract: Disclosed is an apparatus for generating a ranging pseudo noise (PN) code used in a base station of a portable internet system of an orthogonal frequency division multiplexing access scheme, wherein a ranging pseudo noise mask value is generated using a cell ID number, and then the generated ranging pseudo noise mask value is stored in a memory. A final ranging PN code is generated using the stored ranging PN mask value and a status of a pseudo random binary sequence for generating a ranging PN code. With such a structure, the maximal 256-numbered ranging PN code values can be obtained simultaneously with each 144 bit-length.

Abstract: Disclosed is a method and device for requesting and reporting channel quality information in a mobile communication system. A base station a locates a dedicated feedback channel for channel quality information report to an uplink radio resource, transmits the allocation information to subscriber stations, and generates a CQI report message to request channel quality information from the subscriber stations. The subscriber stations receive the CQI report message from the base station, measures a radio channel quality for communication with the base station, generates channel quality information, generates a CQI response message including the channel quality information, and transmit—the CQI response message to the base station through a dedicates feedback channel designated in the allocation information.