Smart antenna system and method thereof for forming uplink eigenbeam of OFDM/TDD

A mobile station transmitter and receiver of a smart antenna system for forming uplink eigenbeams of the OFDM/TDD (orthogonal frequency division multiplex/time division duplex), comprising:

• multiple antennas for transmitting OFDM symbols to a base station receiver, and receiving OFDM symbols from a base station transmitter;
• a mobile station receiver for performing FFT (fast Fourier transform) on a predetermined number of OFDM symbols which are received through a corresponding number of the multiple antennas, outputting FFT-performed symbols as a corresponding number of sets of parallel signals, estimating channels from the sets of parallel signals, detecting signals from the sets of parallel signals using channel estimation results, converting the detected signals into serial signals, and outputting decoded serial signals;
• and
• a mobile station transmitter for converting channel-coded symbols which are input in series into a plurality of parallel signals, generating beam weights from channel matrices of respective pilot tones of each subcarrier according to the channel estimation results of the mobile station receiver, generating OFDM symbols with formed eigenbeams in accordance with the plurality of parallel signals and the beam weights, and outputting the OFDM symbols with formed eigenbeams, wherein the mobile station transmitter comprises a beam weight generator for generating the beam weights from the channel matrices of the respective pilot tones of each subcarrier according to the channel estimation results;
• wherein the beam weight generator comprises:
• a per-pilot spatial covariance matrix generator for receiving per-pilot channel matrices according to the channel estimation results, and generating per-pilot spatial covariance matrices of respective subcarriers;
• a per-subcarrier spatial covariance matrix generator for using a predetermined number of pilot tones provided in a subcarrier, receiving the per-pilot spatial covariance matrices, and generating respective per-subcarrier spatial covariance matrices;
• a short-term spatial covariance matrix generator for using a property that a plurality of downlink subcarriers provided to one user have the same spatial covariance matrix, receiving the respective per-subcarrier spatial covariance matrices, and generating short-term spatial covariance matrices;
• a long-term spatial covariance matrix generator for receiving the short-term spatial covariance matrices, and outputting long-term spatial covariance matrices;
• a per-subcarrier spatial covariance matrix selector for selecting uplink per-subcarrier spatial covariance matrices of subcarriers allocated to an uplink of the per-subcarrier spatial covariance matrix selector from the per-subcarrier spatial covariance matrices;
• an eigen divider for receiving the long-term spatial covariance matrices, dividing the long-term spatial covariance matrices into respective eigenbeams, and outputting the eigenbeams;
• and
• a beam weight selector for receiving the divided eigenbeams and the uplink per-subcarrier spatial covariance matrices, and outputting per-subcarrier beam weights.