A transmission method comprising: generating a first orthogonal frequency division multiplexing, OFDM, frame signal configured to form a grid of multiple frequency subcarriers and multiple time periods, including: information symbols, control symbols, and known reference symbols of a first and of a second type (103, 1801), respectively assigned to time-frequency resource elements in the grid, wherein each resource element is defined by one of the multiple frequency subcarriers and one of the multiple time periods; generating a second orthogonal frequency division multiplexing, OFDM, frame signal configured to form a same grid of multiple frequency subcarriers and multiple time periods, including: information symbols, control symbols, and known reference symbols of the first and of the second type (103, 1801), respectively assigned to time-frequency resource elements in the grid, wherein the known reference symbols of the first type in the first OFDM frame and in the second OFDM frame are assigned to time-frequency resource elements in a first region of the grid to be transmitted continuously in the frequency domain, where the first region is contiguous in time domain to a second region of the grid which includes time-frequency resource elements to which the control symbols are assigned, wherein the known reference symbols of the second type in the first OFDM frame and in the second OFDM frame are assigned to time-frequency resource element in a third region of the grid to be transmitted dispersedly in the time-frequency domain, where the third region is contiguous in time domain to the second region and also includes time-frequency resource elements to which the information symbols are assigned, and wherein the time-frequency resource elements in the grid assigned to the known reference symbols of the first and the second type (103, 1801) in the first OFDM frame signal are different from the time-frequency resource elements in the grid assigned to the known reference symbols of the first and the second type (103, 1801) in the second OFDM frame signal, respectively; converting the first OFDM frame signal to a first radio signal and the second OFDM frame signal to a second radio signal; and transmitting the first radio signal from a first antenna and the second radio signal from a second, different antenna, wherein the known reference symbols of the first type are transmitted for estimating a time and frequency synchronization of each of the first and second OFDM frame signal, and the known reference symbols of the second type are transmitted for deriving a channel estimate for each of the first and the second OFDM frame signal. generating a first orthogonal frequency division multiplexing, OFDM, frame signal configured to form a grid of multiple frequency subcarriers and multiple time periods, including: information symbols, control symbols, and known reference symbols of a first and of a second type (103, 1801), respectively assigned to time-frequency resource elements in the grid, wherein each resource element is defined by one of the multiple frequency subcarriers and one of the multiple time periods; generating a second orthogonal frequency division multiplexing, OFDM, frame signal configured to form a same grid of multiple frequency subcarriers and multiple time periods, including: information symbols, control symbols, and known reference symbols of the first and of the second type (103, 1801), respectively assigned to time-frequency resource elements in the grid, wherein the known reference symbols of the first type in the first OFDM frame and in the second OFDM frame are assigned to time-frequency resource elements in a first region of the grid to be transmitted continuously in the frequency domain, where the first region is contiguous in time domain to a second region of the grid which includes time-frequency resource elements to which the control symbols are assigned, wherein the known reference symbols of the second type in the first OFDM frame and in the second OFDM frame are assigned to time-frequency resource element in a third region of the grid to be transmitted dispersedly in the time-frequency domain, where the third region is contiguous in time domain to the second region and also includes time-frequency resource elements to which the information symbols are assigned, and wherein the time-frequency resource elements in the grid assigned to the known reference symbols of the first and the second type (103, 1801) in the first OFDM frame signal are different from the time-frequency resource elements in the grid assigned to the known reference symbols of the first and the second type (103, 1801) in the second OFDM frame signal, respectively; converting the first OFDM frame signal to a first radio signal and the second OFDM frame signal to a second radio signal; and transmitting the first radio signal from a first antenna and the second radio signal from a second, different antenna, wherein the known reference symbols of the first type are transmitted for estimating a time and frequency synchronization of each of the first and second OFDM frame signal, and the known reference symbols of the second type are transmitted for deriving a channel estimate for each of the first and the second OFDM frame signal.