1. An apparatus for synchronizing a Multi-Input, Multi-Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) system, the apparatus comprising: a number Q of OFDM modulators, each OFDM modulator producing a frame comprising at least one inserted symbol, a plurality of data symbols, and cyclic prefixes; said number Q of transmitting antennas, each transmitting antenna connected to a respective OFDM modulator, for transmitting said frame over a channel; a number L of receiving antennas for receiving the transmitted frames; and said number L of OFDM demodulators, each OFDM demodulator corresponding to a respective receiving antenna, the L OFDM demodulators comprising a synchronization circuit, which processes the received frame in order to synchronize the received frame in the time domain and frequency domain.