Abstract: Automatic Repeat reQuest (ARQ) apparatus and method of a Multiple Input Multiple Output (MIMO system are provided. The ARQ method includes decoding, when one or more packets are received, the received packets and trying to detect the decoded packets; and storing, when error is detected from the packets, the corresponding error packet, requesting a transmitter to retransmit N-ary packets from which the error is detected and to transmit (M-N)-ary new packets when the number of the error packets N is smaller than the total number of the transmitted packets M. Accordingly, the error rate of the retransmitted data can be minimized, the number of retransmissions can be decreased, and the overall data transmission rate can be raised.

Abstract: An apparatus and method for a multiuser receiver in a CDMA communication system are provided. The apparatus includes a plurality of White Matched Filters (WMFs) for pulse shaping received user signals, considering Multiple Access Interference (MAI), and a filter for detecting output signals of the WMFs using a Minimum Mean Square Error (MMSE) scheme, and outputting bit estimation values of the respective users. A transfer function of the WMF is determined by: adding a power spectral density function of the MAI to a power spectral density of an Additive White Gaussian Noise (AWGN); and multiplying an inverse number of the added value by a transfer function (H*(w)) of a Conventional Matched Filter (CMF). Accordingly, the SNIR can be maximized and thus the BER performance may be improved, without additional information, by using the filter in which the power spectral density of the MAI is added to the AWGN and then multiplied by the CMF function.

Abstract: A hybrid forwarding apparatus and method for cooperative relaying in an OFDM network are provided. In a hybrid forwarding apparatus in a relay terminal, a forwarding scheme selector selects a forwarding scheme for transmission. An amplify and forward (AF) block amplifies data received from the forwarding scheme selector, if an AF scheme is selected. A decode and forward (DF) block decodes and encodes data received from the forwarding scheme selector, if a DF scheme is selected. A multiplexer provides the output data of the AF block and the DF block to an OFDM modulator.

Abstract: An apparatus and a method for selecting an antenna appropriate for a data service type in a communication system employing multiple antennas. The method of performing data communication through a transceiver using multiple antennas includes determining the type of the data services contained in a received signal, selecting one of the multiple antennas with a communication quality corresponding to the type of the data services, and employing the selected antenna to perform the data communication.