摘要:
An optimum perturbation apparatus and method in a multi-antenna, multi-user communication system are provided. In the optimum perturbation method, upon receipt of modulation symbols, channel responses are decomposed into eigenvalues and eigenvectors by Single Value Decompositin (SVD) and a distortion value of the modulation symbols is estimated using the eigenvectors and the eigenvalues to minimize noise and interference power. The modulation symbols are precoded by combining the modulation symbols with the estimated distortion value.
摘要:
An optimum perturbation apparatus and method in a multi-antenna, multi-user communication system are provided. In the optimum perturbation method, upon receipt of modulation symbols, channel responses are decomposed into eigenvalues and eigenvectors by Single Value Decompositin (SVD) and a distortion value of the modulation symbols is estimated using the eigenvectors and the eigenvalues to minimize noise and interference power. The modulation symbols are precoded by combining the modulation symbols with the estimated distortion value.
摘要:
A transmitting apparatus and method in an OFDM system are provided. In the transmitting apparatus, a channel information receiver receives channel information. A rate allocator calculates a variable data rate. A scheduler allocates channel resources according to the channel information and the variable data rate.
摘要:
An apparatus and method for determining a beamforming vector in a codebook-based transmission beamforming system are provided. In a feedback method for a receiver in a codebook-based transmission beamforming system, forthcoming channel values for a forthcoming period are generated using M present and previous channel estimates. Effective channel gains for all transmission beamforming vectors included in a codebook are calculated using the forthcoming channel values. A codebook index corresponding to the maximum effective channel gains is fed back to a transmitter.
摘要:
An apparatus and method for determining a beamforming vector in a codebook-based transmission beamforming system are provided. In a feedback method for a receiver in a codebook-based transmission beamforming system, forthcoming channel values for a forthcoming period are generated using M present and previous channel estimates. Effective channel gains for all transmission beamforming vectors included in a codebook are calculated using the forthcoming channel values. A codebook index corresponding to the maximum effective channel gains is fed back to a transmitter.
摘要:
Provided is an apparatus and method for communicating data in a hybrid diversity mode in a broadband wireless communication system. In a method for transmitting data to a subscriber station (SS) in the broadband wireless communication system, null subbands are determined using feedback information received from the SS. TX data to be transmitted to the SS are mapped to a diversity zone from which the null subbands has been excluded. The mapped data are OFDM-modulated and transmitted to the SS. In this way, frequency subbands with poor channel conditions are excluded from data transmission. Accordingly, it is possible to enhance the FER performance and transmit data at a high MCS level.
摘要:
Provided are an apparatus and method for eliminating multi-user interference in a codebook-based beamforming system. A transmitter for providing a service to multi-users in the codebook-based beamforming system includes a beamformer for generating beamformed user signals by multiplying transmit data of users, to whom the service is to be provided, by corresponding weighting factor vectors using feedback information; a null space generator for generating a null space matrix orthogonal to weighting factor vectors of other users; and a projector for projecting the beamformed user signals on the corresponding null space matrix and transmitting the resulting signals through a plurality of antennas. Because the multi-user signals can maintain orthogonality, the performance degradation caused by the multi-user interference can be prevented.
摘要:
Provided are an apparatus and method for eliminating multi-user interference in a codebook-based beamforming system. A transmitter for providing a service to multi-users in the codebook-based beamforming system includes a beamformer for generating beamformed user signals by multiplying transmit data of users, to whom the service is to be provided, by corresponding weighting factor vectors using feedback information; a null space generator for generating a null space matrix orthogonal to weighting factor vectors of other users; and a projector for projecting the beamformed user signals on the corresponding null space matrix and transmitting the resulting signals through a plurality of antennas. Because the multi-user signals can maintain orthogonality, the performance degradation caused by the multi-user interference can be prevented.
摘要:
An adaptive modulation scheme relating to an RA problem for maximizing the transmission rates of all users for maximum transmission rates in an OFDMA system including some users requiring to use services at fixed data rates. The scheme proposes introduction of an adaptive modulation using linear programming into an existing scheme for a system including a single kind of users, thereby enabling simultaneous execution of the adaptive modulation for all users in a system including two kinds of users. Further, the invention proposes another scheme of sequentially allocating subchannels to the users when the fixed transmission rate has a sufficiently small value, in order to reduce the complexity.
摘要:
A communication method in an FH-OFDM communication system having a plurality of BSs is provided. A predetermined number of pilot pattern groups are generated, each pilot pattern group having a predetermined number of different pilot patterns for pilot transmission. The pilot patterns in each of the pilot pattern groups are mapped to different FH sequence sets. The pilot patterns and FH sequence sets are assigned to the BSs so that MSs within the service areas of the BSs can identify the BSs.