Abstract: In a symbol mapping method, transmission data is encoded to output information bits and redundancy bits. The information bits and the redundancy bits are mapped to a symbol according to a first mapping scheme at a first transmission, and the information bits and the redundancy bits are mapped to a symbol according to a second mapping scheme at a second transmission.

Abstract: The present invention provides a method of bandpass sampling which particularly includes the single-sideband signal conversion procedure prior to the sampling process in the purpose of lowering the required sampling frequency. Conversion of the bandpass RF signal into a single-sideband spectrum signal which has the spectrum components only in either the positive or the negative frequency domain is accomplished by bandpass-filtering, or more effectively by using a Hilbert transformer. This invention includes a method of finding the minimum sampling frequency for simultaneous frequency down-conversion of multiple RF bandpass signals.

Abstract: The present invention relates to an apparatus and a method for selection of a precoding matrix. In the present invention, a precoding matrix to enable an effective signal-to-noise ratio (ESNR) to have a maximum value with respect to a signal vector that requires retransmission is selected in a codebook and fed back to a transmitter. Accordingly, since the effective signal-to-noise ratio has the maximum value after the signal vector is retransmitted, it is possible to minimize a reception error probability of retransmission.

Abstract: A handover method of a mobile station in a wireless mobile communication system and a system therefore are provided. The mobile station transmits a handover indication message to a serving base station, receives a ranging response message that comprises authentication information required for the mobile station to authenticate a target base station, receives fast ranging resources and transmits a ranging response acknowledgement (ACK) message, which comprises authentication information required for the target base station to authenticate the mobile station, to the target base station after receiving the fast ranging resources. Accordingly, a handover break time is minimized.

Abstract: A relay method of a wireless communication system according to one embodiment of the present invention relates to a relay method of a wireless communication system in which at least one relay device communicates with a base station. The relay method comprises the steps of: each relay device setting information about a frequency band to be relayed, composing a control signal including the information about the set frequency band, and transmitting the control signal to at least one relay device; and receiving the control signal, extracting the information about the frequency band included in the control signal, amplifying the signal according to the information about the frequency band set in each relay device, and transmitting the amplified signal to at least one terminal.

Abstract: A resource allocation method in a wireless communication system for providing a communication service in a given system frequency band to access terminals (ATs) within a broad-band service area around an access point (AP) and to ATs within a narrow-band service area having a radius larger than the radius of the broad-band service area. In the resource allocation method, the system frequency band is divided into a Time Division Duplexing (TDD) interval and a Frequency Division Duplexing (FDD) interval in time, and the TDD interval and the FDD interval are defined as TDD resources and FDD resources, respectively. The TDD resources are allocated to an AT within the broad-band service area, and the FDD resources are allocated to an AT within the narrow-band service area.

Abstract: A Base Station (BS) operation method for reducing load terminals based on load estimation of a neighbor cell in a wireless communication system includes receiving information for estimating a load of a neighbor BS, determining whether to determine the power control and handover terminal set using the number of terminals serviced by the neighbor BS, the number of overload terminals among the terminals serviced by the neighbor BS, and the backoff counter value, and, when it is determined to determine a power control and handover terminal set, deciding the power control and handover terminal set to minimize load terminals, based on the first power variation and the second power variation.

Abstract: An apparatus for and method of transmitting and/or receiving a signal by using signaling point rotation in mutually cooperative relaying are provided.

Abstract: A beacon scheduling method in multi-hop ad-hoc communications is provided. This method can prevent overhead in a manner that a base station (BS) transmits beacon slot information to a carrier sense multiple access (CSMA)/collision avoidance (CA) node (CN) and a gateway (GW) through contention-free time division multiple access (TDMA) communications at initial clustering, the CN and the GW performs a sequential clustering to forward the beacon slot information to a cluster head (CH), the CH aggregates joining messages from nodes and assigns non-colliding beacon slots to the nodes, and the GW uses a beacon slot frame of a beacon transmission period (BTP) used by its selected CH in a beacon reply period (BRP) as well. Accordingly, the CH does not need to separately perform the initialization to elect the beacon slot, and the GW also does not require a separate initialization to select the beacon relay slot.

Abstract: A method and system for efficiently transmitting data, to which scalable image coding has been applied over a single frequency network is provided. The system includes a control server which re-packetizes data packets, received from a multimedia server, into a scalable bit stream by separately encoding the data packets into a base layer and one or more enhancement layers, and at least one base station which adaptively multicasts and broadcasts the scalable bit stream, received from the control server, to a plurality of terminals located in the area of a cell. The at least one base station multicasts and broadcasts the base layer across the area of the cell, and adaptively transmits the one or more enhancement layers depending on channel status or terminal performance of the plurality of terminals.

Abstract: A method and apparatus for allocating a radio resource in a wireless sensor network are provided, in which a signal requesting a radio resource allocation is received from any one of sensors included in the wireless sensor network, an amount of remaining energy is compared with respect to each zone where a sensor transmitting the signal is included, an order of zones, from a zone comprising a greatest amount of remaining energy to a zone having a least amount of remaining energy, is determined as a result of the comparison, and a time slot is allocated to a sensor of each zone according to the determined order of zones, when transmitting a frame for the radio resource allocation.

Abstract: An apparatus and method for transmitting in a multi-user multi-antenna system are provided. The apparatus includes a precoder for orthogonalizing a channel by removing a channel element of a corresponding terminal with respect to multiple terminals, for determining an effective channel of each terminal by decomposing the orthogonalized channel using Singular Value Decomposition (SVD), for determining a precoding matrix using the effective channel, and for mapping data streams of the multiple terminals to a plurality of transmit antennas using the precoding matrix, and the plurality of the transmit antennas for transmitting the data streams of the multiple terminals. Hence, it is possible to obtain an iteration algorithm performance requiring considerable computation while avoiding complexity and reducing computation.

Abstract: A method for staggered zone resource allocation in an orthogonal frequency division multiple access (OFDMA) system having a cluster includes: dividing a frequency resource of the OFDMA system into a plurality of time zones along a time axis; determining at least two resource allocation start zones among the plurality of time zones in at least two cells of the cluster, respectively; arranging users in each of the at least two cell according to a path loss in a descending order; and sequentially allocating the frequency resource to the arranged users from the at least two resource allocation start zones in the at least two cells, respectively.

Abstract: An apparatus and method for reducing MAP channel overhead in a broadband wireless communication system. In a Base Station (BS), a traffic classifier classifies transmission data into a first group and a second group according to user channel information and packet sizes of the transmission data. A MAP channel configure configures a MAP channel to include information about users of the first group and positions of data for the users, information indicating whether users of the second group have succeeded in random access in a second uplink data region of a previous frame, and information about resource reservation for a current frame for the second group. A channel mapper maps the first group to a first downlink data region and maps the second group to a second downlink data region according to the MAP channel.

Abstract: A device for generating a transmission codebook in a communication system including a multi-input multi-output (MIMO) antenna according to an embodiment of the present invention includes: a frequency determiner that determines a frequency to allow the transmission codebook to have an optimal characteristic; a precoding matrix generator that generates a precoding matrix on the basis of the frequency; and a codebook generator that generates a retransmission codebook to be used for retransmission on the basis of the precoding matrix and generates the transmission codebook on the basis of the retransmission codebook.

Abstract: In a symbol mapping method, transmission data is encoded to output information bits and redundancy bits. The information bits and the redundancy bits are mapped to a symbol according to a first mapping scheme at a first transmission, and the information bits and the redundancy bits are mapped to a symbol according to a second mapping scheme at a second transmission.

Abstract: An apparatus and a method for selecting one of a plurality of relay modes in a wireless communication system are provided. The method includes checking a channel state between a Mobile Station (MS) and each of at least one Relay Station (RS), selecting the relay mode for supporting a relay service using the determined channel state between the MA and each of the at least one RS, and providing the relay service to the MS using the selected relay mode. Thus, system throughput and outage performance can be enhanced by using the appropriate relay mode based on the MS distribution or the channel condition.

Abstract: The present invention provides a method of bandpass sampling which particularly includes the single-sideband signal conversion procedure prior to the sampling process in the purpose of lowering the required sampling frequency. Conversion of the bandpass RF signal into a single-sideband spectrum signal which has the spectrum components only in either the positive or the negative frequency domain is accomplished by bandpass-filtering, or more effectively by using a Hilbert transformer. This invention includes a method of finding the minimum sampling frequency for simultaneous frequency down-conversion of multiple RF bandpass signals.

Abstract: Provided is a low-complexity transmit/receive antenna selection method for Multi-Input Multi-Output (MIMO) systems. The method includes the steps of generating a gain matrix of receive channel, calculating norm values of channel gains for each row (receive antennas) and column (transmit antennas) of the generated gain matrix of the receive channel, selecting an antenna with the maximum norm value among the calculated norm values of channel gains, and repeatedly performing the process of alternately selecting transmit and receive antennas having the maximum channel gain value among the channel gain values of the selected antenna until a required number of antennas is all selected.

Abstract: The present invention relates to an apparatus and a method for selection of a precoding matrix. In the present invention, a precoding matrix to enable an effective signal-to-noise ratio (ESNR) to have a maximum value with respect to a signal vector that requires retransmission is selected in a codebook and fed back to a transmitter. Accordingly, since the effective signal-to-noise ratio has the maximum value after the signal vector is retransmitted, it is possible to minimize a reception error probability of retransmission.