说明：  MC-CDMA with SFBC In the next subsections, we describe the architecture of an SFBC MIMO MC-CDMA transmitter, and define the basic terms related to the PAPR of the involved signals. System model In an MC-CDMA system, a block of M information symbols each active user are spread in the frequency domain into N = LM subcarriers, where L represents the spreading factor. This is accomplished by multiplying every symbol of the block for user k, where k ∈ {0,1,..., L - 1}, by a spreading code ,