Ergodic interference alignment, as introduced by Nazer et al (NGJV), is a
technique that allows high-rate communication in n-user interference networks
with fast fading. It works by splitting communication across a pair of fading
matrices. However, it comes with the overhead of a long time delay until
matchable matrices occur: the delay is q^n^2 for field size q.
In this paper, we outline two new families of schemes, called JAP and JAP-B,
that reduce the expected delay, sometimes at the cost of a reduction in rate
from the NGJV scheme. In particular, we give examples of good schemes for
networks with few users, and show that in large n-user networks, the delay
scales like q^T, where T is quadratic in n for a constant per-user rate and T
is constant for a constant sum-rate. We also show that half the single-user
rate can be achieved while reducing NGJV's delay from q^n^2 to q^(n-1)(n-2).
This extended version includes complete proofs and more details of good
schemes for small n.Comment: Extended version of a paper presented at the 2012 International
Symposium on Information Theory. 7 pages, 1 figur
