Abstract: A method includes receiving from a first station at a second station at least two space-time coded signals in respective formed beams of a multi-beam antenna array associated with the first station; receiving from the first station, in a signaling channel, a value representing a transmit power level; determining power control coefficients for each of the space-time coded signals; and transmitting the power control coefficients to the first station, wherein the control coefficients are for in part adjusting transmit power.

Abstract: A method includes receiving at least two space-time coded signals from an antenna system associated with a first station, determining complex channel state information based on the received space-time coded signals, and sending the complex channel state information to the first station. In an alternative embodiment, a method includes transmitting at least two space-time coded signals in respective beams of a multi-beam antenna array, measuring a channel impulse response for each space-time coded signal at a second station, and sending an indicia of a selected set of least attenuated signals from the second station to the first station. The multi-beam antenna array is associated with a first station. The beams transmit a signature code embedded in each respective space-time coded signal, and the signature codes are orthogonal so that the second station can separate and measure the channel impulse response corresponding to each space-time coded signal.

Abstract: A method includes receiving at least two space-time coded signals from an antenna system associated with a first station, determining complex channel state information based on the received space-time coded signals, and sending the complex channel state information to the first station. In an alternative embodiment, a method includes transmitting at least two space-time coded signals in respective beams of a multi-beam antenna array, measuring a channel impulse response for each space-time coded signal at a second station, and sending an indicia of a selected set of least attenuated signals from the second station to the first station. The multi-beam antenna array is associated with a first station. The beams transmit a signature code embedded in each respective space-time coded signal, and the signature codes are orthogonal so that the second station can separate and measure the channel impulse response corresponding to each space-time coded signal.

Abstract: A method includes receiving a reference signal and at least one delayed space-time encoded signal via at least two beams in which a time delay is associated with at least one of the at least two beams; determining channel state information based on the received reference signal and the received at least one delayed space-time encoded signal; and segmenting the channel state information into a plurality of channel state information segments.

Abstract: The present invention relates to a method and system for transmitting a transmission signal from an antenna array (19) to a receiving means (20) of a wireless communication system, wherein a signal quality measurement is performed at the receiving means (20) for predetermined antennas or beams of said antenna array (19). Based on a feedback information derived from the signal quality measurement, at least two of the predetermined antennas or beams of the antenna array (19) are selected. The selected antennas or beams are used for transmitting said transmission signal according to a transmit diversity or beamforming scheme. Thus, spectral efficiency and diversity gain can be enhanced by using only selected ones of the predetermined antennas or beams.

Abstract: The invention relates to a method of transmitting data from a transmitter to a receiver in a radio system, and to a radio system.

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: The invention relates to a radio system including transceivers. One of the transceivers includes, for instance, a device for comparing a parameter representing signal quality measured from the received signal with at least one threshold value and a device for determining a quality class for the performance of a MIMO common channel. At least one of the transceivers includes a device for storing the observations made by the second transceiver about the quality class transitions of the transfer channel of the first transceiver and a device for estimating the next quality class of the transfer channel of the first transceiver from the stored quality class transition observations.

Abstract: An apparatus and method are provided for stabilizing terminal power in antenna ports. A data transmission/reception method is provided for terminal power stabilization in a communication system using multiple antennas. An optimal antenna immune to absorption loss due to human body proximity is selected from among multiple antennas connected to a single port when a data service is provided. Data for the data service is transmitted and received through the selected antenna.

Abstract: An apparatus and method for controlling power in a multi-hop relay broadband wireless communication system are provided. A BS sends a signal to an RS and an MS to estimate distances between the BS, the RS and the MS. Upon receipt of signals from the RS and the MS, the BS measures ToAs of the received signals and detects time information included in the received signals, and calculates propagation delays between the BS, the RS and the MS based on the ToAs and the time information. The BS estimates the distances between the BS, the RS and the MS using the propagation delays, and controls transmission power according to the estimated distances.

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.

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: The invention relates to a method and a system for implementing diversity in transmission utilizing orthogonal antenna beams formed using digital beam forming methods. In this method antenna beams are directed to be adjacent so as to set at least one of the estimated directions of arrival of the received signal within the range between antenna amplification maximums of the antenna beams and signal is sent using said antenna beams. An advantage provided by the method and system of the invention is to improve the performance of the system in the downlink direction and also to reduce the imbalance between the uplink performance and the downlink performance. The method of the Invention also allows to carry out power control specifically for each antenna beam.

Abstract: An apparatus and method for preventing power imbalance between antennas in a closed-loop MIMO system are provided. In a transmitter in the MIMO system, a first calculator generates a vector by multiplying a transmission vector by a beamforming matrix and a second calculator generates a plurality of antenna signals by multiplying the vector by a predetermined phase rotation matrix.

Abstract: A method includes receiving at least two space-time coded signals from an antenna system associated with a first station, determining complex channel state information based on the received space-time coded signals, and sending the complex channel state information to the first station. In an alternative embodiment, a method includes transmitting at least two space-time coded signals in respective beams of a multi-beam antenna array, measuring a channel impulse response for each space-time coded signal at a second station, and sending an indicia of a selected set of least attenuated signals from the second station to the first station. The multi-beam antenna array is associated with a first station. The beams transmit a signature code embedded in each respective space-time coded signal, and the signature codes are orthogonal so that the second station can separate and measure the channel impulse response corresponding to each space-time coded signal.

Abstract: A method of directional radio communication between a first station and a second station, the method comprising the steps of defining at the first station a plurality of beam directions available for transmitting successive signals from the first station, selecting at said first station at least one of said directions for transmission of a signal from said first station to said second station, wherein the selection of the at least one direction for transmission is such that successive signals or groups of signals are transmitted in substantially different directions and such that on average each beam direction available to said first station is used substantially equally.

Abstract: The invention relates to a data transmission method and a radio system comprising at least one subscriber terminal and at least one base station including an antenna, by means of which the base station transmits signals to the subscriber terminal. The subscriber terminal includes a measuring mechanism which determines the quality of the signals received by the subscriber terminal by comparing the received signals with at least one signal quality threshold level. When only one signal exceeds the threshold, the subscriber terminal sends to the base station, which transmitted the signal that exceeded the threshold, a command to use, when transmitting a signal to the subscriber terminal, the antenna with which the signal that exceeded the threshold was transmitted, or the transmission direction to which the signal that exceeded the threshold was transmitted.

Abstract: The invention relates to a data transmission method and a radio system comprising at least one subscriber terminal and at least one base station including an antenna, by means of which the base station transmits signals to the subscriber terminal. The subscriber terminal includes a measuring mechanism which determines the quality of the signals received by the subscriber terminal by comparing the received signals with at least one signal quality threshold level. When only one signal exceeds the threshold, the subscriber terminal sends to the base station, which transmitted the signal that exceeded the threshold, a command to use, when transmitting a signal to the subscriber terminal, the antenna with which the signal that exceeded the threshold was transmitted, or the transmission direction to which the signal that exceeded the threshold was transmitted.

Abstract: The invention relates to a method of transmitting data in a radio channel from a transmitter to a receiver, and to a transmitter and a receiver implementing the method. The method includes setting a radio channel quality requirement according to the user and system information; setting a data transfer delay requirement; determining a radio channel coherence time; channel encoding the data; selecting interleaving depth using the radio channel coherence time and the data transfer delay as decisive parameters; interleaving the channel coded data; if the radio channel quality requirement is not fulfilled, selecting at least one transmit diversity antenna besides the main antenna so that the radio channel quality requirement will be fulfilled; transmitting modulated, interleaved and channel coded data with the selected antennas.