Abstract: Disclosed is an apparatus and a method for estimating a state of a reception buffer, and processing a downlink frame based on the estimated state of the reception buffer in a wireless terminal. The method includes continuously monitoring a level of a reception buffer; determining based on the level of the reception buffer whether to store the incoming data frame; discarding the incoming data frame when the level of the reception buffer is insufficient for storage of the incoming data frame; and reporting to a transmitter that the incoming data frame has been discarded.

Abstract: A dividing apparatus and method using coordinate rotation is disclosed. To this end, a plurality of rotation stages are sequentially performed until a divisor reaches a criterion and a rotation direction used in each of the plurality of stages is output. A division result acquired by performing rotation with respect to a dividend using the rotation direction for each of the plurality of stages is output.

Abstract: A terminal location estimation method in a wireless communication system in which an access point (AP) provides an access service to a plurality of terminals includes defining a plurality of beam spaces around the AP through space multiplexing; scheduling the beam spaces according to a predetermined pattern; simultaneously forming a beam in at least one beam space; and detecting the existence and location of a terminal according to whether a response message in response to the formed beam is received. Accordingly, an AP forms beams in a predetermined scheduling pattern, and each of the terminals detecting the beams registers its location by informing the AP that each of the terminals exists in a relevant beam area, and thus, a location of each of the terminals can be estimated without using a complex DOA algorithm.

Abstract: Provided is a coding/decoding apparatus for an orthogonal frequency division multiple access (OFDMA) communication system that takes multiple users into consideration and uses block coding/decoding scheme. In the apparatus, a mapper determines paths through which information of users will be provided, according to states of sub-channels allocated to the users. A coding/decoding unit parallel-processes the information of the users through the paths selectively connected by the mapper. The coding/decoding unit includes coders/decoders having performance lower than the maximum processing performance determined taking into account a size of a processing block and the number of sub-channels.

Abstract: In a medium access method for contention and non-contention, a poll number for stations, or wireless terminals for communication, is managed by a base station so as to guarantee smooth traffic and improved Quality of Service (QoS). A first group of stations is provided for the non-contention, and a second group of stations is provided for the contention. The method includes (a) preparing a contention-free access message attempting access of the first group, (b) detecting a transmission time of a contention access message attempting access of the second group, (c) embedding the contention-free access message in the contention access message so as to transmit the embedded message to at least one of the first and second groups, and (d) receiving the contention access message, in which the contention-free access message is embedded, at the at least one of the first and second groups, and endowing any one of the first and second groups with a priority to attempt access to a medium in turn.

Abstract: A Medium Access Control (MAC) apparatus and method for use in a channel overlay network of a wireless access system. The wireless access system, which is based on a multi-carrier, includes a plurality of physical modules for receiving signals from a plurality of terminals, a plurality of MAC (Medium Access Control) modules for processing the signals received via the physical modules while being classified according to predetermined traffic classes, and a controller connected to the MAC modules for integratedly managing the MAC modules. The MAC apparatus includes an additional MAC module used for a control channel and a plurality of MAC modules for supporting various QoS traffic data according to individual classes, thereby improving scheduling complexity in a MAC layer.

Abstract: A handoff method is provided in a communication network including a plurality of fixed nodes attached to a router connected to at least one external network, and at least one mobile node associated with a current fixed node. The method detects movement of a mobile node; prepares a handoff of the mobile node from a current fixed node to potential fixed nodes upon detecting movement of the mobile node; decides whether to handoff to one of the potential fixed nodes as a target fixed node; and performs the handoff from the current fixed node to the target fixed node. The handoff method enables the mobile station to quickly move its association from one access point to another by minimizing a probe delay which is a primary contributor to handoff delay.

Abstract: An HARQ method for guaranteeing a QoS in a wireless communication system is provided. In a transmitting apparatus using a HARQ for transmitting packet data in a wireless communication system, a retransmission controller determines the size of redundancy information for correcting transmission errors in packet data, and a transmitter transmits the redundancy information of the determined size upon request for a retransmission of the packet data. Transmission of redundancy information of a variable size at each retransmission satisfies the QoS required for each user, maximizes a data throughput, and allows for the efficient reception of an ACK or a NACK for the redundancy information.

Abstract: A method for transmitting data at a high rate in a wireless LAN is provided. A wireless access point requests reliable node information from a wireless terminal having a transfer rate equal to or less than a predetermined transfer rate if data to be transmitted to the terminal occurs. The terminal produces a frame containing information related to reliable nodes that can communicate with the terminal and information of greatest transfer rates between the reliable nodes and the terminal, and transmits the frame to the access point. The access point selects an optimal relay node from the reliable nodes, based on the greatest transfer rates between the reliable nodes and the access point and transfer rates between the reliable nodes and the terminal, and determines if a relay gain exists when using the optimal node. If the relay gain exists, the access point performs relay transmission to the terminal; otherwise, it performs direct transmission to it.

Abstract: A method and apparatus controls power consumption of stations having a hierarchical structure when the stations transmit and receive a wireless signal to and from one another on a CSMA/CA wireless LAN. The controlling involves extracting information on frame transmission speed and transmission period information on first and second layers of the hierarchical structure from the wireless signal; determining a power-controlled period for each of the first and second layers based on the extracted information; and reducing the power consumption of the first and second layers by switching a current mode of the first and second layers to a predetermined mode for the power-controlled period if a reception address included in the extracted information is not identical to an address of the station.

Abstract: Local communication system in wireless communication system includes a main wireless terminal negotiating with each of the peripheral wireless terminals during a time period for which a frame will be transmitted, generating a schedule map including negotiated time information and a transmission sequence of each of the peripheral wireless terminals, and transmitting the generated schedule map to all peripheral wireless terminals; and the peripheral wireless terminals storing the schedule map received from the main wireless terminal, and performing communication with the main wireless terminal according to the sequence determined in the schedule map for the negotiated time period.

Abstract: There are provided efficient basis conversion matrices Dsd and Dds and a basis conversion method in a finite field GF(2n) using the basis conversion matrices for a case where a defining polynomial is a pentanomial, xn+xk(3)+xk(2)+xk(1)+1, and the exponents n, k(3), k(2), and (k1) satisfy the condition, n−k(3)>k(3)−k(1). In addition, an apparatus for the basis conversion in the finite field GF(2n) is provided. Since a pentanomial having a general form in an arbitrary degree is used as the defining polynomial, basis conversion between a standard representation and a dual representation is efficiently performed. Consequently, a dual basis multiplier can be efficiently implemented.