As the backbone of the fifth generation, 5G communications, Orthogonal Frequency Division Multiplexing, OFDM is seen to be reliable in addressing Inter-symbol Interference, ISI issues as well as providing high-speed access to broadband. Channel estimation and tracking are generally carried out by transmitting known pilot symbols in given positions of the frequency-time grid. However, the use of a fixed amount of pilot for all channel circumstances is hugely detrimental. Several methods, especially on block-type and comb-type pilot arrangement, have presented. In this paper, the method of determining the pilot space depends on the current channel quality. The proposed technique focused on improving estimation and bandwidth in time-varying and frequency-selective fading channels without increasing the complexity and sacrifice the bandwidth efficiency of the OFDM system.
