  Faster-than-Nyquist (FTN) signaling is a nonorthogonal transmission
technique, which brings in intentional inter-symbol interference. This way it
can significantly enhance spectral efficiency for practical pulse shapes such
as the root raised cosine pulses. This paper proposes an achievable rate region
for the multiple antenna (MIMO) asynchronous multiple access channel (aMAC)
with FTN signaling. The scheme applies waterfilling in the spatial domain and
precoding in time. Waterfilling in space provides better power allocation and
precoding helps mitigate inter-symbol interference due to asynchronous
transmission and FTN. The results show that the gains due to asynchronous
transmission and FTN are more emphasized in MIMO aMAC than in single antenna
aMAC. Moreover, FTN improves single-user rates, and asynchronous transmission
improves the sum-rate, due to better inter-user interference management.
