  The combination of singular value decomposition (SVD)-based beamforming and
filter bank multicarrier with offset quadrature amplitude modulation
(FBMC/OQAM) has not been successful to date. The difficulty of this combination
is that, the beamformers may experience significant changes between adjacent
subchannels, therefore destroy the orthogonality among FBMC/OQAM real-valued
symbols, even under channels with moderate frequency selectivity. In this
paper, we address this problem from two aspects: i) an SVD-FS-FBMC architecture
is adopted to support beamforming with finer granularity in frequency domain,
based on the frequency spreading FBMC (FS-FBMC) structure, i.e., beamforming on
FS-FBMC tones rather than on subchannels; ii) criterion and methods are
proposed to smooth the beamformers from tone to tone. The proposed finer
beamforming and smoothing greatly improve the smoothness of beamformers,
therefore effectively suppress the leaked ICI/ISI. Simulations are conducted
under the scenario of IEEE 802.11n wireless LAN. Results show that the proposed
SVD-FS-FBMC system shares close BER performance with its orthogonal frequency
division multiplexing (OFDM) counterpart under the frequency selective
channels.
