Abstract: In transmitting a wireless packet signal for channel response estimation, after AGC preambles and channel estimation preambles are transmitted by using a plurality of antennas, at least one data stream is transmitted, as subcarriers distributed to the plurality of antennas, by using the plurality of antennas.

Abstract: wireless communication apparatus (transmitter) including a plurality of antennas for transmitting a plurality of known symbol sequences and data symbols, transmits the known symbol sequences, each of the known symbol sequences including a plurality of known symbols, each of the known symbols whose plural known information being carried on a plurality of subcarriers, a phase of last known symbol of the each of the known symbol sequences being rotated, and transmits the data symbols after the known symbol sequences are transmitted.

Abstract: Radio communication apparatus for receiving OFDM signal from base station and transmitting FH signal to base station, using sub-channels, base station comparing hopping pattern information items indicating hopping patterns from radio communication apparatuses including radio communication apparatus, and generating collision information when hopping patterns include colliding hopping patterns, includes estimation unit configured to estimate channel response values of sub-channels based on OFDM signal, selector which selects, from sub-channels, several sub-channels which have higher channel response values than a value, each of channel response values being expressed by power level, signal-to-noise power ratio, or signal-to-interference ratio, determination unit configured to determine hopping pattern from selected sub-channels, transmitter which transmits, to base station, hopping pattern information item indicating determined hopping pattern, receiver which receives collision information from base station, an

Abstract: A wireless communication apparatus having a plurality of antennas for transmitting a known symbol by using a plurality of subcarriers to a receiver, the known symbol including known information, the apparatus includes each of the subcarriers which carries the known information being classified into at least two groups, and a phase control unit configure to control inversion/non-inversion of a phase of the known information carried on two subcarriers which belong to the same group in accordance with notification information to be notified to the receiver.

Abstract: A wireless communication apparatus includes a plurality of antennas, transmits a plurality of known symbol sequences each including a plurality of known symbols by using the antennas, each of the known symbols having subcarrier arrangement on which plural known information of the each of the known symbols are carried on, and inversion/non-inversion of a phase of known information on one of two adjacent subcarriers of the subcarrier arrangement being controlled in accordance with the number of the known symbols and time position of the each of the known symbols, and transmits data symbols by using the antennas after the known symbol sequences are transmitted.

Abstract: Before data is transmitted from a plurality of antennas, a plurality of known symbol sequences are transmitted from these antennas. Each known symbol sequence contains a plurality of known symbols having different subcarrier arrangements. Known symbols transmitted from different antennas have different subcarrier arrangements.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.