Abstract: A railroad vehicle monitoring system installed on a railroad vehicle includes: wireless sensor devices installed at attached equipment of the railroad vehicle, including a sensor that senses statuses of the attached equipment, configured to wirelessly transmit a sensing value sensed by the sensor in real time, and including an energy harvester configured to convert energy generated by running of the railroad vehicle into electric energy, and supply the electric energy as a power source for the sensor, a signal process in the sensing value, and wireless communication of the sensing value; sink node devices configured to wirelessly receive the sensing value and output, in real time, railroad vehicle status information obtained by integrating the received sensing value; and a vehicle status monitoring device configured to receive the railroad vehicle status information, integrate and manage the railroad vehicle status information, and output the integrated railroad vehicle status information in real time.

Abstract: A wireless sensor device includes: an energy harvester configured to convert vibration generated from a broadband vibration source into electricity, an elastic member arranged to receive the vibration and a communication unit fixed by the elastic member, supplied with the converted electricity from the energy harvester, and configured to transmit sensing information obtained by sensing a measurement target. The elastic member operates as a mechanical filter configured to limit a frequency range and an acceleration magnitude of the vibration to be transferred to the communication unit for stabilizing the performance of the communication unit, and the communication unit is arranged to receive vibration passing through the elastic member.

Abstract: A railroad vehicle monitoring system installed on a railroad vehicle includes: wireless sensor devices installed at attached equipment of the railroad vehicle, including a sensor that senses statuses of the attached equipment, configured to wirelessly transmit a sensing value sensed by the sensor in real time, and including an energy harvester configured to convert energy generated by running of the railroad vehicle into electric energy, and supply the electric energy as a power source for the sensor, a signal process in the sensing value, and wireless communication of the sensing value; sink node devices configured to wirelessly receive the sensing value and output, in real time, railroad vehicle status information obtained by integrating the received sensing value; and a vehicle status monitoring device configured to receive the railroad vehicle status information, integrate and manage the railroad vehicle status information, and output the integrated railroad vehicle status information in real time.

Abstract: Disclosed is a method for allocating and accessing downlink resources in the OFDMA communication system. In the resource allocation method, bursts having the same modulation and channel encoding level are arranged in a predetermined temporal order on a physical layer. Information on the allocated unit resources is included in a common control block and is transmitted to a subscriber station, and the subscriber station then detects a number of the allocated unit resources to thus check the range of bursts to be received by the subscriber station. Therefore, power consumption by the subscriber station is reduced and signaling overheads of the common control information and unneeded residual resources are decreased.

Abstract: The subscriber station of claim 15, wherein the uplink data includes data to be transmitted, and a header having information on the data and the subscriber, and the uplink data generator adds the subheader includDisclosed is a method and device for requesting and reporting channel quality information in a mobile communication system. An uplink radio resource for a subscriber station having data to transmit is allocated and a CQI indicator for requesting channel quality information is added to the allocation information to be transmitted to a subscriber station. The subscriber station having received the uplink radio resource allocation information generates channel quality information by measuring the radio channel quality for communication with the base station according to existence of the indicator and transmits desired uplink data having the generated channel quality information to the base station.

Abstract: A method for requesting and reporting channel quality information (CQI) in a wireless portable Internet system is disclosed. Timing of a channel quality information request by a base station is determined, existence of an automatic repeat request acknowledgment (ARQ_ACK) message of downlink data is determined on requesting the channel quality information from the subscriber station, the automatic repeat request acknowledgment message and the radio resource for the channel quality report to the subscriber station is allocated, the automatic repeat request acknowledgment message and the channel quality report information is received, and a modulating and coding level of downlink data is determined by extracting the channel quality report information form the automatic repeat request acknowledgment message.

Abstract: Disclosed is a method for a preamble-based bandwidth request. The present invention enables state control of a subscriber station based on the latest environment in a portable Internet system requesting a bandwidth using a preamble, and hence allows a subsequent more efficient transmission of user data. In addition, the present invention provides information for discrimination of the subscriber station transmitting the preamble as well as state control information of the subscriber station to the base station during a preamble-based bandwidth request by the subscriber station, and enables the base station to discriminate the subscriber station in the next time of data transmission with the subscriber station.

Abstract: A method for requesting and reporting channel quality information (CQI) in a wireless portable Internet system is disclosed. Timing of a channel quality information request by a base station is determined, existence of an automatic repeat request acknowledgment (ARQ_ACK) message of downlink data is determined on requesting the channel quality information from the subscriber station, the automatic repeat request acknowledgment message and the radio resource for the channel quality report to the subscriber station is allocated, the automatic repeat request acknowledgment message and the channel quality report information is received, and a modulating and coding level of downlink data is determined by extracting the channel quality report information form the automatic repeat request acknowledgment message.

Abstract: Provided is a method of scheduling packets in a mobile telecommunication. The method includes the steps of: a) calculating a normalized standard data unit (SDU) drop rate based on the number of SDUs that will be dropped if the SDUs will not transmitted in a next slot, the number of SDUs dropped unit a current slot, the number of SDUs transmitted until the current slot and a maximum SDU drop rate allowed at each session; b) selecting sessions to transmit in a next slot and deciding a transmission amount of each session at a current slot based on the normalized SDU drop rate; and c) performing the steps a) and b) until all basic units (BU) in one slot are used.

Abstract: A method for requesting and reporting channel quality information (CQI) in a wireless portable Internet system is disclosed. Timing of a channel quality information request by a base station is determined, existence of an automatic repeat request acknowledgment (ARQ_ACK) message of downlink data is determined on requesting the channel quality information from the subscriber station, the automatic repeat request acknowledgment message and the radio resource for the channel quality report to the subscriber station is allocated, the automatic repeat request acknowledgment message and the channel quality report information is received, and a modulating and coding level of downlink data is determined by extracting the channel quality report information from the automatic repeat request acknowledgment message.

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 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.

Abstract: Disclosed is a power saving mode control system (200) and method in a wireless portable Internet system. Stations in the sleep mode are grouped by aligning listening intervals of the stations which enter the sleep mode in the power saving management system wherein the sleep interval for receiving no traffic data is exponentially increased. Therefore, the sleep mode of the grouped subscriber stations are easily managed, and power saving efficiency is enhanced and system complexity is lowered by easily and quickly detecting data states provided to the corresponding stations.

Abstract: The traffic indication and channel adaptation apparatus for a subscriber station in a sleep mode according to the present invention includes: a channel resource allocator for generating resource allocation information allocating an uplink channel resource to the subscriber station; a traffic indication and channel adaptation controller for generating a traffic indication message transmitted with the resource allocation information to the subscriber station, and providing a downlink data having a transmission level determined by applying an AMC level according to a CQI report message transmitted from the subscriber station; a transmitter for transmitting the uplink resource allocation information, the traffic indication message, and the downlink data to the subscriber station; and a receiver from receiving a CQI codeword or a CQI report message.

Abstract: Provided is a method for generating a feedback message for ARQ including recording an ACK type in a first field; estimating the last block sequence number of successively ACKed blocks and recording the estimated last block sequence number in a second field; recording the number of groups of successively ACKed blocks after the estimated last block sequence number as the number of ACK MAPs in a third field; recording the startblock sequence number of the respective ACK MAPs in a fourth field; recording the lengths of the respective ACK MAPs in a fifth field corresponding to the recorded start block sequence number; and sending a feedback message including information on the first to the fifth fields.

Abstract: Provided is a method of scheduling packets in a mobile telecommunication. The method includes the steps of: a) calculating a normalized standard data unit (SDU) drop rate based on the number of SDUs that will be dropped if the SDUs will not transmitted in a next slot, the number of SDUs dropped unit a current slot, the number of SDUs transmitted until the current slot and a maximum SDU drop rate allowed at each session; b) selecting sessions to transmit in a next slot and deciding a transmission amount of each session at a current slot based on the normalized SDU drop rate; and c) performing the steps a) and b) until all basic units (BU) in one slot are used.

Abstract: The present invention relates to a method for retransmitting a packet in a mobile communication system. A waiting time for retransmission is established when a packet transmitted from a transmission unit to a receipt unit has no ACK message. A maximum number of times for retransmitting the packet is established when an NACK message is received. The ARQ transmitter moves to a discard state when the maximum management time of the ARQ block expires or the number of times of retransmissions exceeds the maximum number of times of retransmissions, and checks the ACK message receipt. The packet in the transmission buffer is discarded regardless of whether the distant message is transmitted or the discard message is transmitted or the discard message is checked when the ACK message is received.

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.

Abstract: Information for different subscribers of a service with the same modulation and channel encoding method is transmitted by allocating radio resources in a wireless portable Internet system. Also, identifier information on the subscriber of a concurrently allocated radio resource is transmitted through common control information. Therefore, information for a plurality of subscribers coexists in a single radio resource block, and it can be easily transmitted. Since a subscriber station which has received downlink information can know to which radio resource block the information for the corresponding station is allocated through the subscriber identifier information transmitted as common control information, the subscriber station can access desired information by accessing a specific radio resource block to which information for the subscriber is allocated in the received frame.

Abstract: The traffic indication and channel adaptation apparatus for a subscriber station in a sleep mode according to the present invention includes: a channel resource allocator for generating resource allocation information allocating an uplink channel resource to the subscriber station; a traffic indication and channel adaptation controller for generating a traffic indication message transmitted with the resource allocation information to the subscriber station, and providing a downlink data having a transmission level determined by applying an AMC level according to a CQI report message transmitted from the subscriber station; a transmitter for transmitting the uplink resource allocation information, the traffic indication message, and the downlink data to the subscriber station; and a receiver from receiving a CQI codeword or a CQI report message.