On the diversity multiplexing tradeoff in a 4-user clustered Z-channel

We study a new interference channel called 4-user clustered Z-channel where 4 clusters consisting of two single-antenna nodes each construct a Z interference channel and the connected two clusters form a two-user interference channel. We analyze diversity multiplexing tradeoff (DMT) in this channel by joint decoding. We also propose a new interference alignment scheme requiring only partial channel phase information and analyze DMT for the proposed interference alignment scheme. Eventually, we show that the proposed interference alignment and joint decoding should be switched depending on multiplexing gain for better DMT performance. It is also shown that the hybrid scheme is DMT optimal in the range between 0 and 0.2 and at the point 0.5.