As the combining form of the orthogonal frequency-division multiplexing (OFDM) technique and the vertical Bell Labs layered space-time (V-BLAST) architecture

the OFDM V-BLAST system can better meet the demand of next-generation (NextG) broadband mobile wireless multimedia communications.This paper investigates the decoding problem of the downlink OFDM V-BLAST system under the frequency-selective fading environment.The joint space-frequency demultiplexing operation in the OFDM V-BLAST system is firstly addressed.Successively

one novel half-rate rotational invariance joint space-frequency coding scheme is proposed for the OFDM V-BLAST system.By elegantly exploiting the above rotational invariance property

one direct decoding algorithm without knowing channels state information (CSI) is derived for the downlink frequency-selective OFDM V-BLAST system.Extensive simulation results demonstrate the validity of the novel half-rate rotational invariance joint space-frequency coding scheme and the performance of the direct decoding algorithm.