Figure 2
From: Bounds on the capacity regions of half-duplex Gaussian MIMO relay channels
Cut-sets that determine the outer bound region . (a) Cut-set 1 (bounding rate of information transmitted by node 1): node 1 → relay, node 2. (b) Cut-set 2 (bounding rate of information received by node 2): node 1, relay → node 2. (c) Cut-set 3 (bounding rate of information transmitted by node 2): node 2 → relay, node 1. (d) Cut-set 4 (bounding rate of information received by node 1): node 2, relay → node 1.