Towards an Extremal Network Theory – Robust GDoF Gain of Transmitter Cooperation over TIN

We study the GDoF gain of transmitter cooperation (TC) over power control and treating interference as noise (TIN) for 3 regimes - a TIN regime where TIN is GDoF optimal for the K user IC, a CTIN regime where the GDoF region achieved by TIN is convex without time-sharing, and an SLS regime where a simple layered superposition scheme is optimal in the K user MISO BC for K≤3. Under finite precision CSIT, appealing to extremal network theory we obtain the following results. In the TIN regime as well as the CTIN regime, the extremal GDoF gain from TC over TIN is Θ (1). In fact, the gain is at most a factor of 2 in the CTIN regime and exactly 3=2 in the TIN regime for K > 1. In the SLS regime, the extremal GDoF gain is Θ(log(K)).