PROJECT TITLE :

The Degrees of Freedom of Two-Unicast Layered MIMO Interference Networks With Feedback

ABSTRACT:

Two-unicast layered interference networks beneath the Shannon feedback and limited Shannon feedback settings are studied from a degrees of freedom (DoF) perspective. The main focus is on the archetypal 2-hop multiple-input, multiple-output (MIMO) $(M,N), times , (M,N) ,times , (M,N) $ network, denoted here because the $(M,N)^3$ network, that may be a layered 2-unicast network with two transmitters, two relays, and 2 receivers, with the primary hop network between the transmitters and therefore the relays, and the second hop network between the relays and therefore the receivers, each being MIMO Gaussian interference channels. In particular, the primary transmitter–receiver try and the first relay have $M$ antennas each and also the second transmitter–receiver pair and also the second relay having $N$ antennas every. The (full) Shannon feedback setting for the $(M,N)^3$ network is one in that the transmitters have delayed data of the first and second hop channel coefficients and therefore the relay and destination outputs and the relays have delayed information of the second hop channel coefficients and destination outputs. The DoF region beneath this setting is established. A key lead to this paper shows that this Shannon feedback DoF region will after all be achieved with abundant less facet information—beneath what we tend to seek advice from as the restricted Shannon feedback setting—whereby the transmitters have no channel state or output feedback whatsoever and solely the $M$ -antenna relay (assuming $M geq N$ ) has delayed data of the coefficients of the second-hop channel and of only the received signal of the $N$ -antenna receiver. For this restricted Shannon feedback setting, the DoFs region of the $(M,N)^3$ network is established by introducing a retro-cooperative interference alignment scheme. These DoF region results for the $(M,N)^3$ network with feedback are extended to more general layered interference networks together with the two-unicast $l$ -hop layered networks plus layered networks with additional general numbers of antennas at the numerous terminals.