Interference Alignment and Degrees of Freedom of the
-User Interference Channel
For the fully connected K user wireless interference channel where the channel coefficients are time-varying and are drawn from a continuous distribution, the sum capacity is characterized as C(SNR)=K/2log(SNR)+o(log(SNR)) . Thus, the K user time-varying interference channel almost surely has K/2 degrees of freedom. Achievability is based on the idea of interference alignment. Examples are also provided of fully connected K user interference channels with constant (not time-varying) coefficients where the capacity is exactly achieved by interference alignment at all SNR values.
Published in:
Information Theory, IEEE Transactions on
(Volume:54
,
Issue:
8
)
Date of Publication: Aug. 2008