Time and frequency correction for an access point in an ofdma communication system

A method for time and frequency error correction in an access point of an OFDMA WiMAX communication system, the method comprising the step of:

• detecting embedded pilot signals in mobile station data traffic after FFT and with removed Cyclic Prefix;
• estimating a time error by calculating a pilot signal phase difference along a tone index within the same OFDM symbol;
• estimating a frequency error by calculating a pilot signal phase difference across multiple OFDM symbols within a tone;
• determining if at least one of the estimated time and frequency errors exceed a predetermined threshold;
• and
• correcting the time and frequency errors in the access point by using a symbol rotation of transmit data.

An access point operable to correct time and frequency errors, the access point station comprising:

• a receiver operable to receive mobile station data traffic;
• a processor coupled to the receiver and transmitter, the processor operable to detect embedded pilot signals in the data traffic;
• estimate a time error by calculating a pilot signal phase difference across a tone index within the same OFDM symbol;
• estimate a frequency error by calculating a pilot signal phase difference across a multiple OFDM symbols within a tone;
• and correct the time and frequency errors in the access point by using a symbol rotation of transmit data.