Patent ID: 8174957

Claim:
A method for transmitting a plurality of reference signals in a wireless multiple-input multiple-output (MIMO) communication system, the method comprising: allocating, by a base station, the plurality of reference signals for multiple antennas in a sub-frame, the sub-frame comprising a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols in a time domain over a plurality of sub-carriers in a frequency domain; and transmitting the plurality of reference signals for the multiple antennas in the sub-frame, wherein a first array is repeated in the frequency domain on a first OFDM symbol of the sub-frame, a second array is repeated in the frequency domain on a second OFDM symbol of the sub-frame and a third array is repeated in the frequency domain on a third OFDM symbol of the sub-frame, wherein each of the first, second and third arrays consist of six contiguous symbols in the frequency domain, wherein a first symbol and a fourth symbol of the six contiguous symbols of each of the first, second and third arrays are allocated with a reference signal of the plurality of reference signals, wherein the first and fourth symbols of the six contiguous symbols of each of the first, second and third arrays are directly followed by two contiguous data symbols, wherein a first reference signal “TI” for a first antenna is allocated on the first symbol in the first array and the fourth symbol in the third array, a second reference signal “T 2 ” for a second antenna is allocated on the fourth symbol in the first array and the first symbol in the third array, a third reference signal “T 3 ” for a third antenna is allocated on the first symbol in the second array, and a fourth reference signal “T 4 ” for a fourth antenna is allocated on the fourth symbol in the second array, wherein fourth and fifth OFDM symbols which do not include the plurality of reference signals are allocated between the second OFDM symbol and the third OFDM symbol, and wherein sixth and seventh OFDM symbols which do not include the plurality of reference signals are allocated, such that the sixth OFDM symbol is contiguous with the third OFDM symbol, and the seventh OFDM symbol is contiguous with the sixth OFDM symbol.