Ofdm frame communication method and apparatus

A reception method comprising:

• receiving a first radio signal transmitted from a first antenna at a transmitter and a second radio signal transmitted from a second antenna at the transmitter different from the first antenna,
• converting the first radio signal to a first orthogonal frequency division multiplexing (OFDM) frame signal and the second radio signal to a second OFDM frame signal,
• wherein the first OFDM frame signal includes a grid of multiple frequency subcarriers and multiple time periods, each time period with the multiple frequency carriers corresponding to a first OFDM symbol such that the first OFDM frame includes multiple first OFDM symbols, where a first OFDM symbol is carried on multiple frequency subcarriers during a time period, the first OFDM frame including known, first reference OFDM symbols located at corresponding time-frequency resource elements in the grid, each resource element being defined by a one of the multiple frequency subcarriers and one of the multiple time periods, and
• wherein the second OFDM frame signal includes the grid of multiple frequency subcarriers and multiple time periods, each time period with the multiple frequency carriers corresponding to a second OFDM symbol such that the second OFDM frame includes multiple second OFDM symbols sharing the same grid of multiple frequency subcarriers and multiple time periods as the first OFDM frame, where a second OFDM symbol is received on multiple frequency subcarriers during a time period, the second OFDM frame including known, second reference OFDM symbols that are located at corresponding time-frequency resource elements in the grid which are different than the corresponding time-frequency resource elements to which the known, first reference OFDM signals are located at the first OFDM frame signal, and
• using the known, first reference OFDM symbols in the first OFDM frame signal and the known, second reference OFDM symbols in the second OFDM frame signal to demodulate the first OFDM frame signal and the second OFDM frame signal.