Comparison of distributed space and frequency interference alignment
Résumé
This paper addresses multiple access in MIMO
wireless networks. It compares two distributed interference
alignment techniques, in space and in frequency, that both
aim at removing interferences through orthogonalization. The
theoretical advantages and drawbacks of each technique are
highlighted. Then, the multiplexing gain and the computational
complexity are analytically evaluated. It is shown that frequency
interference alignment achieves a higher multiplexing gain than
space interference alignment in realistic network conditions,
and always requires a lower computational complexity. Finally,
the performances of both algorithms with varying number of
interfering links are assessed via numerical simulations. Space
interference alignment fulfills complete interference suppression,
and consequently provides the same spectral efficiency to all
links, regardless of the number of interfering links. Frequency
interference alignment is less efficient in terms of INR, and the
spectral efficiency per link thus decreases when the number of
links increases. Nevertheless, the spectral efficiency is always
higher with frequency interference alignment than with space
interference alignment.