Beamformer Design with Smooth Constraint-Free Approximation in Downlink Cloud Radio Access Networks

摘要: It is known that data rates in standard cellular networks are limited due to inter-cell interference. An effective solution of this problem use the multi-cell cooperation idea. In Cloud Radio Access Network, which a candidate 5G and beyond, applied by means central processors (CPs) connected simple remote radio heads with finite capacity fronthaul links. study, we consider downlink scenario aim minimize total power spent designing beamformers. We case where perfect channel state information not available CP. The original includes discontinuous terms many constraints. propose novel method transforms into smooth constraint-free form found gradient descent approach. As comparison, optimal solving an extensive number convex sub-problems, heuristic search algorithm some sparse techniques. Heuristic methods find subset all possible sub-problems. Sparse techniques apply norm approximation ($\ell_0/\ell_1, \ell_0/\ell_2$) or make objective function more tractable. also derive theoretical performance bound order observe how far proposed performs off when running prohibitive computational complexity. Detailed simulations show close one, it outperforms other analyzed.