Abstract: A base station calculates the number of terminals which have transmitted messages at ith frame, and calculates the number of messages to be transmitted at (i+1)th frame by using the number of terminals which have transmitted the messages in the ith frame. The base station calculates a transmission probability by using the number of messages to be transmitted in the (i+1)th frame and the number of random access slots, and transmits the number of messages to be transmitted in the (i+1)th frame and the transmission probability to the plurality of terminals. The base station receives a message transmitted by a pertinent terminal, whose number of messages to be transmitted in the (i+1)th frame is greater than the number of random access slots, among the plurality of terminals, according to the result obtained by comparing the transmission probability and a random number.

Abstract: Provided is that a base station that receives an index and a path attenuation difference of a monitoring sector from a mobile station and receives an amount of interference of the monitoring sector from a base station that corresponds to the monitoring sector. In addition, the base station measures an interference state of the monitoring sector by using the amount of interference and the path attenuation difference and calculates a control value of uplink power based on the interference state of the monitoring sector. Further, the base station transmits the control value of the uplink power to the mobile station.

Abstract: In a communication system including a plurality of base stations and a plurality of terminals belonging to each of the base stations, the base station receives information on subcarriers allocated to a terminal that belongs to an adjacent base station from the adjacent base station. Thereafter, the base station generates power control information on the basis of the subcarrier information and transmits the power control information to the terminal, and the terminal controls uplink power on the basis of the received power control information. At this time, the power control information, as information based on estimating hitting between subcarriers used by the terminal that belongs to the base station and subcarriers used by the adjacent base station, may be a ratio found by dividing the total number of subcarriers used by each terminal that belongs to the adjacent base station by the entire number of subcarriers that can be used by the base station.

Abstract: The embodiments of the present invention are directed to a method and apparatus that synchronize radio nodes using preambles in a radio communication system. An embodiment of the present invention relates to a method of transmitting preambles by a radio node. The method includes generating a first preamble indicating a system bandwidth and a carrier configuration, generating a second preamble indicating a segment identifier used for obtaining a node identifier, allocating the first preamble to a first preamble carrier set, allocating the second preamble to a second preamble carrier set corresponding to the segment identifier, and transmitting the first preamble to a receiving node through the first preamble carrier set and the second preamble to the receiving node through the second preamble carrier set.

Abstract: The present invention relates a symbol generation apparatus for multiple antennas having low receiving complexity and having flexibility with respect to an increase in the number of antennas. The symbol generation apparatus includes a plurality of space-time channel encoders respectively corresponding to a plurality of channels, and an inverse fast Fourier transformer group. The respective space-time channel encoders receive a digital-modulated symbol group from the corresponding channel, perform a space-time encoding operation with respect to a plurality of space areas and at least one time area, shift phases by using a plurality of phase values, and generate a plurality of phase-shifted space-time codewords.

Abstract: Systems and methods for selecting a puncturing pattern for a low density parity check (LDPC) code are disclosed. One such method comprises: selecting a puncture pattern distribution for the LDPC code; calculating a security threshold and a reliability threshold for the LDPC, the LDPC having the selected puncture pattern distribution and also described by a degree distribution; storing the selected puncture pattern distribution responsive to a security gap for the LDPC being a lowest value encountered in any prior iterations; selecting another puncture pattern distribution for the LDPC code; and repeating the calculating, the storing, and the selecting another puncture pattern distribution steps.

Abstract: There is provided a method of performing distributed synchronization in an Ad hoc network system. The method includes receiving a signal, including a reception time point change period, through a plurality of nodes, changing a reception time point at which the signal is received through the plurality of nodes within the reception time point change period so that the reception time point is included in a preset Cyclic Prefix (CP) period, changing a Fast Fourier Transform (FFT) start time point which is a time point at which data starts being recovered based on the changed reception time point, and changing the reference point of the transmission time point of each of the plurality of nodes based on a difference value between the preset reference point of the FFT start time point and the changed FFT start time point. The method has smaller overhead.

Abstract: An apparatus for setting a pilot subcarrier in an antenna selects candidates of power value variables of a pilot subcarrier existing within a predetermined range, and calculates and extracts pilot subcarriers of a predetermined number on the basis of a nonlinear function among the candidates of the selected power value variables. Next, the apparatus removes pilot subcarriers of a predetermined number from the extracted pilot subcarriers of a predetermined number in accordance with a rule and configures the antenna on the basis of position values of final pilot subcarriers except for a virtual subcarrier among the removal result. Further, the apparatus configures the antenna on the basis of the power value by determining the sum total of the power values corresponding to the position values of the final pilot subcarriers to correspond to the number of pilot subcarriers.

Abstract: A wireless local area network (WLAN) access point (AP) system is provided. The WLAN AP system includes a first virtual access point (VAP) that is logical entity performing communication with a first station (STA); and a second VAP performing communication with a second STA. The first VAP uses a first channel to exchange a frame with the first STA and the second VAP uses a second channel to exchange a frame with the second STA.

Abstract: Disclosed is a decoding method and device for low density parity check codes using dynamic scheduling. The low density parity check codes are sequentially decoded, and the messages are scheduled in the descending order of the difference between values before and after updating the message transmitted from the variable node to the check node.

Abstract: A mobile station receives a MIMO feedback mode bitmap and information on a MIMO feedback period. The mobile station estimates channel information corresponding to at least one MIMO feedback mode indicated by the MIMO feedback mode bitmap. The mobile station generates a MIMO feedback including the MIMO feedback mode bitmap and the channel information corresponding to the at least one MIMO feedback mode indicated by the MIMO feedback mode bitmap. The mobile station transmits the MIMO feedback at the advent of the MIMO feedback period.

Abstract: A system for spatial division multiple access using a wireless repeater having a single transmitting/receiving antenna, includes: a base station that selectively transmits a plurality of data stream signals to the wireless repeater within an area through a multi-transmitting antenna for downlink; and at least one wireless repeater that forms a wireless repeater group within the base station area and repeats the data stream signals selectively transmitted from the base station to terminals.

Abstract: The present invention relates to a multiple antenna transmission system and a signal transmission method In the signal transmission method using multiple antennas, a plurality of subcarrier symbols are grouped as a plurality of groups including first and second tiles that are basic resource management units including two or more subcarriers included in a set frequency domain, phases of subcarrier symbols included in a first tile are shifted to be a first phase shifting value, and phases of subcarrier symbols included in a second tile are shifted to be a second phase shifting value that is different from the first phase shifting value.

Abstract: The present invention relates to a channel state transmission method using time domain coefficient quantization. A terminal measures channel information in the time domain and transmits it to a base station. In this instance, a multipath frequency selective fading channel is displayed in a tapped delay line format configured with a per-path path delay value and a path gain in the time domain, differentiates a quantization level for each path gain for more efficient transmission, quantizes the same, and transmits it to a transmitter. Therefore, while the amount of bandwidths required for transmitting state information from the terminal to the base station is reduced, the base station can efficiently acquire channel state information on the entire bandwidths. Also, the base station transmits signals to many terminals through beamforming by using the acquired reliable channel state information, thereby increasing the terminal's signal receiving performance.

Abstract: The present invention relates to a beamforming method and apparatus. A beamforming method for use in a base station for transmitting a plurality of streams through a plurality of antennas includes: receiving feedback information including information on a first codeword selected from a codebook including a plurality of codewords from each of a plurality of user terminals; grouping the plurality of user terminals by use of the feedback information from each user terminal; determining a user terminal to which a plurality of streams will be assigned of the plurality of user terminals, and determining a second codeword to be used for beamforming from the codebook by use of the feedback information of each user terminal and grouping information; and multiplying data to be transmitted through the plurality of steams by the second codeword and a unitary matrix.

Abstract: The present invention relates to an uplink control channel configuration in a mobile wideband wireless access system, and an allocation method thereof. An uplink control channel includes a long cyclic prefix used to improve interference and distortion caused by multipath transmission characteristics of an initial ranging or handover ranging signal and a periodic ranging or band request ranging signal. In addition, a short orthogonal frequency division multiple (OFDM) symbol is used to transmit uplink control information when one terminal exists or the number of terminals is small.

Abstract: A node synchronization apparatus in a wireless network system sets a fast Fourier transform (FFT) start point and requests a one-hop neighbor node to change its transmission time. The synchronization apparatus sets a signal receiving time and requests a one-hop neighbor node to change a receiving time. In this way, a node synchronizes signal transmission and signal reception.

Abstract: The present invention relates to a method for allocating a frequency domain spread code in a base station of a multi-carrier code division multiple access (MC-CDMA) communication system. A code allocation priority is established based on interference between previously allocated spread codes and a newly allocated spread code so as to minimize the interference caused by channel fading or a synchronization error according to a transmitting or receiving timing offset when a scheduler of the base station in the MC-CDMA communication system allocates a subcarrier group to the plurality of user terminals or channels, and the spread code is allocated to the plurality of user terminals or channels according to the established priority, by the scheduler of the base station.

Abstract: A method of allocating a resource by a base station is provided. The base station allocates a plurality of radio resources for transmitting a plurality of data bursts to a plurality of subframes in one frame, respectively, and generates a resource allocation information signal including allocation information on the plurality of radio resources. The base station transmits the resource allocation information signal to a mobile station through one subframe.

Abstract: A cell search system for a mobile station in a time division duplex system includes: a primary synchronization code search module for searching primary synchronization codes and comparing frame values of the primary synchronization codes to determine a position of the maximum value; a correlation module for estimating a phase value and acquiring a first correlation value; a secondary synchronization code search module for generating determinative variables and storing them based on the position of the maximum value; a comparison and decision module for detecting a maximum value of the determinative variables, comparing it with the values stored in the secondary synchronization code search module to count matching values, and comparing the count value with a system value to decide whether slot synchronization and group acquisition is successful; and a base station determination module for determining a second correlation value between midamble codes and the received signals, and selecting a maximum value of it