Schemes of pilot pattern design of channel estimation in adaptive cognitive MIMO-OFDM system: Review

MIMO-OFDM is commonly used for communication system because it provides high data rates and fading effect which is introduced by multipath propagation; the system is robust against it. In MIMO-OFDM, channel estimation is a crucial technique for the estimation of the transmitted signal bits upon the received signal bits. Designing pilot pattern is an important step to realize PSA-OFDM. For channel estimator designing in wireless OFDM systems, the arrangement of pilot information is an important task, in which pilot is a reference signal employed by both transmitter and receiver. In this paper, we present a research on constraining requisites of pilot patterns such as the number and the interval of pilot symbols. Then, different types of pilot patterns and usage scenarios are summarized roundly.