  Spectral precoding is a promising technique to suppress out-of-band emissions
and comply with leakage constraints over adjacent frequency channels and with
mask requirements on the unwanted emissions. However, spectral precoding may
distort the original data vector, which is formally expressed as the error
vector magnitude (EVM) between the precoded and original data vectors. Notably,
EVM has a deleterious impact on the performance of multiple-input
multiple-output orthogonal frequency division multiplexing-based systems. In
this paper we propose a novel spectral precoding approach which constrains the
EVM while complying with the mask requirements. We first formulate and solve
the EVM-unconstrained mask-compliant spectral precoding problem, which serves
as a springboard to the design of two EVM-constrained spectral precoding
schemes. The first scheme takes into account a wideband EVM-constraint which
limits the average in-band distortion. The second scheme takes into account
frequency-selective EVM-constraints, and consequently, limits the signal
distortion at the subcarrier level. Numerical examples illustrate that both
proposed schemes outperform previously developed schemes in terms of important
performance indicators such as block error rate and system-wide throughput
while complying with spectral mask and EVM constraints.
