Multicarrier data transmission schemes have been widely studied and, to some degree, employed as high-speed wireless data transmission schemes between two independent communication devices or in wireless telecommunication systems. Such multicarrier data transmission schemes include, for example, an Orthogonal Frequency Division Multiplexing (OFDM) scheme. In multicarrier systems, several data symbols are typically transmitted in parallel on a plurality of subcarriers. In order to enable data transmission between a transmitter and a receiver, the receiver must be able to detect a given synchronization or pilot signal transmitted by the transmitter. The synchronization or pilot signal may be attenuated due to fading caused by a radio channel and, thus, it may arrive at a very low power level at the receiver. Thus, an efficient signal detection method is needed for detecting synchronization signals and/or pilot signals within a multicarrier signal received in a radio receiver.
In OFDM systems, signal detection may be carried out either in a time or a frequency domain. Signal detection is typically based on correlation of a received signal processed for detection. A signal detection procedure may be blind or pilot assisted. In blind signal detection, autocorrelation properties of the received signal, particularly the correlation properties caused by the use of a cyclic prefix, are typically employed. In pilot assisted signal detection, the received signal is correlated with a known signal, and if the two signals have enough correlation, it is determined that the signal has been detected.
In OFDM systems, a pilot signal is typically transmitted on a given subcarrier or subcarriers of a multicarrier signal. A radio receiver receives the multicarrier signal and, in an A/D converter, converts it into digital samples having a given sample rate. Then, the radio receiver extracts the pilot signal from the multicarrier signal, for example by filtering the multicarrier signal. Since the pilot signal represents only a fraction of the total bandwidth of the multicarrier signal, processing the pilot signal with the sample rate resulting from the A/D conversion results in unnecessary calculations and in large memory sizes. This increases the complexity, cost, and power consumption of the radio receiver.