Aiming at the problems that the former recognition algorithms for STBC-OFDM (Space-Time Block Code with Orthogonal Frequency Division Multiplexing) need too many received symbols

sensitive to frequency offset and not suitable for single received antenna

a method based on the fourth order lag product(FOLP) is proposed.According to the correlation between received STBC symbols

the FOLP of received signals is deduced

and a peak test algorithm is proposed to identify the STBCs.Unlike other methods

this algorithm does not require any prior information of channel coefficients

noise information

modulation type and start of OFDM block and

is well-suited for single received antenna context.The proposed method provides a good performance with low sensitivity to impairments in the received signals

such as time offset

phase noise and frequency offset.It can be applied in cognitive radio systems

spectrum surveillance

and so on.