Patent ID: 8149934

Claim:
A method of transmitting pilot signals by allocating pilot subcarriers for use in downlink or uplink communication in a multiple-input multiple-output (MIMO) antenna system using orthogonal frequency division multiplexing (OFDM) modulation, the method comprising: allocating first pilot signals for a first antenna in time and frequency domains comprising OFDM symbols in the time domain and subcarriers in the frequency domain; allocating second pilot signals for a second antenna in the time and frequency domains; and transmitting the first and the second pilot signals to a receiver, wherein each first pair consisting of one among the first pilot signals and one among the second pilot signals is allocated in two contiguous OFDM symbols, wherein the first pairs allocated within the same OFDM symbols are allocated in a unit of 9 subcarriers in the frequency domain, wherein the first pilot signal and the second pilot signal are alternately allocated within each OFDM symbol, and wherein each of the first pilot signals separated by two OFDM symbols is shifted by multiple of three subcarriers, and each of the second pilot signals separated by two OFDM symbols is shifted by multiple of three subcarriers.