Abstract: The present invention relates to channel estimation in uplink OFDMA systems and in particular to an efficient channel estimation method involving superimposed training for equalization in uplink OFDMA systems. The method is also directly applicable to the uplink in important linearly pre-coded versions of OFDMA like SC-FDMA. Importantly, the invention provides for the first time iterative time domain least squares based channel estimation method of superimposed training based uplink OFDMA/SC-FDMA wherein the training sequence for such channel estimation is optimal in terms of BER minimization. Hence the method according to the present invention is of improved accuracy and is well suited for practical implementation. The method of the invention can have wide application in various wireless communication systems and enabled devices, cellular systems, handheld devices, computers, PDAs and cell phones and the like.

Abstract: A system and a method for estimating low complexity bandwidth efficient carrier frequency offset for orthogonal frequency division multiple access (OFDMA) and or single carrier frequency division multiple access (SC-FDMA) uplink transmissions in a communication network systems comprising a group of subscriber stations, a base station including carrier frequency offset unit, said method steps comprising: transmitting plurality of null subcarrier signals and data subcarrier signals from plurality of said subscriber stations (SS) to the base station; processing said transmitted subcarrier signals at the base station by estimating carrier frequency offset (CFO) by means carrier frequency offset unit; selecting the subcarrier signals based on carrier assignment scheme (CAS); characterized in that said step of estimating carrier frequency offset comprising: generating a trial carrier frequency offset (CFO) vector thereafter point to point multiplying said trial carrier frequency offset (CFO) vector with the receive