Common use of Time Sharing Clause in Contracts

Time Sharing. Time sharing is considered in [15] in the secrecy rate region of the Gaussian interference channel (without public channel) where the transmission period is divided into two non-overlapping slots with time fractions ρ1 0 and ρ2 0, where ρ1 + ρ2 = 1. In slot 1 with time fraction ρ1, BS1 sends its confidential message where BS2 is silent. In slot 2 with time fraction ρ2, BS2 sends its confidential message while BS1 remains silent. Hence, in each slot, the channel reduces to a simple Gaussian wiretap channel [15]. We change the time sharing scheme in [15] in such a way that in time fraction ρ1, BS2 sends a signal as well which is not intended as a confidential message but it can be used in the backward phase using the public channel. In slot 2 with time fraction ρ2, the symmetric actions are done. Therefore, in slot 1, we set: V1f = X1 = N (0, β1P1), V2f = φ, X2 = N (0, β2P2), and in slot 2, V2f = X2 = N (0, β2P2), V1f = φ, X1 = N (0, β1P1), where 0 β1 1, 0 β2 1 are power-control parameters. Then in the backward phase, we set V1b = Y1, V2b = Y2. By substituting the auxiliary random variables in Theorem 1 as described, the corollary below is resulted.