Achievable Degrees of Freedom of the K-User Interference Channel With Partial Cooperation
In this paper, the authors consider the K-user interference channel with partial cooperation, where a strict subset of the K users cooperates. For the -user interference channel with cooperating subsets of length M, the outer bound of the total degrees of freedom is KM/(M+1). In this paper, they propose a signal space-based interference alignment scheme that proves the achievability of these degrees of freedom for the case K=M+2. The proposed scheme consists of a design for the transmit pre-coding matrices and a processing algorithm which they call the Successive Interference Alignment (SIA) algorithm. The decoder of each message uses the SIA algorithm to process the signals received by the M cooperating receivers in order to get the maximum available degrees of freedom.