5 research outputs found
Joint transceiver design for MIMO channel shortening.
Channel shortening equalizers can be employed
to shorten the effective impulse response of a long intersymbol
interference (ISI) channel in order, for example, to decrease the
computational complexity of a maximum-likelihood sequence
estimator (MLSE) or to increase the throughput efficiency of an
orthogonal frequency-division multiplexing (OFDM) transmission
scheme. In this paper, the issue of joint transmitter–receiver filter
design is addressed for shortening multiple-input multiple-output
(MIMO) ISI channels. A frequency-domain approach is adopted
for the transceiver design which is effectively equivalent to an
infinite-length time-domain design. A practical space–frequency
waterfilling algorithm is also provided. It is demonstrated that the
channel shortening equalizer designed according to the time-domain
approach suffers from an error-floor effect. However, the
proposed techniques are shown to overcome this problem and
outperform the time-domain channel shortening filter design. We
also demonstrate that the proposed transceiver design can be considered
as a MIMO broadband beamformer with constraints on
the time-domain multipath length. Hence, a significant diversity
gain could also be achieved by choosing strong eigenmodes of the
MIMO channel. It is also found that the proposed frequency-domain
methods have considerably low computational complexity as
compared with their time-domain counterparts