We can group all cells into c ₄ = ?2 ? + 6 ? ² lattices. Each lattice consists of nodes that are ?2 ? + 6 ? / m apart along the X-axis or the Y-axis (see Fig. 2.2). The cells of each lattice can be active at the same time since

• the transmission range from a node to a neighboring node is at most 2/ m, and

• any interfering transmitters are at least (2 ? + 2)/ m distance away from the receiver.

We can schedule the c ₄ lattices in a round-robin fashion and each lattice is active for 1/ c ₄ amount of time.