A novel time domain approach for the downlink pilot design of multiantenna OFDM systems

A novel time domain approach is introduced for the downlink pilot design of multiantenna OFDM systems. Zero correlation zone sequence sets are used to construct the pilot sequences so that the intra-and inter-cell interferences between pilots are cancelled. The pilot sequences are superimposed on the time domain data signals directly and keep interference-free because of the special frequency domain property of sequences. The overhead of pilots can adapt the number of the transmit antennas. Analysis, typical design example and numerical results demonstrate that a good performance-to-complexity tradeoff and lower pilot overhead compared to traditional frequency domain approaches can be obtained by the proposed approach.