The channel estimation techniques based on pilot arrangement for OFDM systems are investigated in this book. The channel estimation based on block type pilot arrangement is performed by sending pilots at every sub-channel and using this estimation for a fixed number of symbols. The channel for block-type pilot arrangement is estimated by Least Square (LS) or Minimum Mean-Square (MMSE) estimators. The channel estimation based on comb type pilot arrangement is performed by inserting pilot tones into each OFDM symbol. The channel estimation based on comb type pilot arrangement is studied and...