| 摘要 |
According to methods and apparatus taught herein, an Orthogonal Frequency Division Multiplexed (OFDM) transmitter increases pilot density in the edge regions of an OFDM signal, such as by using additional pilot sub carriers in the edge regions. For example, the OFDM signal includes first pilot sub carriers uniformly distributed across the frequency band of the OFDM signal, and second pilot sub carriers distributed within the edge regions. A corresponding OFDM receiver circuit uses the increased pilot density to improve channel estimation. For example, the receiver circuit uses the first pilot sub carriers in a Maximum Likelihood (ML) estimation process to obtain first channel estimates, and uses the results of ML estimation along with the second pilot sub carriers in a Minimum Mean Square Error (MMSE) estimation process to obtain second channel estimates. The receiver forms the improved channel estimates using the first and second channel estimates.
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