Patent ID: 8649447

Claim:
In a single transmit branch orthogonal frequency-division multiplexing (OFDM) signal comprising a plurality of symbols, each symbol having a plurality of closely-spaced, orthogonal data sub-carrier signals carrying data, a method comprising: inserting one or more pilot sub-carrier signals with the data sub-carrier signals, each pilot sub-carrier signal being modulated with a predetermined pilot modulation scheme; and placing each pilot sub-carrier signal at an adjacent sub-carrier signal location for a first duration of some successive symbols of the OFDM signal to form a sliding pilot sub-carrier signal, each pilot sub-carrier signal being placed at a same sub-carrier signal location for a second duration of other successive symbols of the OFDM signal, such that for each pair of consecutive symbols in the OFDM signal, each pilot sub-carrier signal is placed either at the same sub-carrier signal location or at an adjacent sub-carrier signal location, wherein over a third duration of the plurality of symbols at least one pilot sub-carrier signal is placed at each data sub-carrier signal location of the OFDM signal for at least one symbol.