Coordination and Antenna Domain Formation in Cloud-RAN systems

TL;DR

This paper addresses the problem of antenna domain formation in cloud-RAN systems, proposing a distributed algorithm to minimize interference and improve system sum-rate through layered coordination.

Contribution

It introduces a novel interference-aware optimization framework and a low-overhead distributed algorithm for antenna domain formation in cloud-RAN systems.

Findings

Significant increase in system sum-rate with proposed ADF mechanism

Effective distributed algorithm for antenna domain formation

Layered coordination improves beamforming performance

Abstract

We study here the problem of Antenna Domain Formation (ADF) in cloud RAN systems, whereby multiple remote radio-heads (RRHs) are each to be assigned to a set of antenna domains (ADs), such that the total interference between the ADs is minimized. We formulate the corresponding optimization problem, by introducing the concept of \emph{interference coupling coefficients} among pairs of radio-heads. We then propose a low-overhead algorithm that allows the problem to be solved in a distributed fashion, among the aggregation nodes (ANs), and establish basic convergence results. Moreover, we also propose a simple relaxation to the problem, thus enabling us to characterize its maximum performance. We follow a layered coordination structure: after the ADs are formed, radio-heads are clustered to perform coordinated beamforming using the well known Weighted-MMSE algorithm. Finally, our simulations show that using the proposed ADF mechanism would significantly increase the sum-rate of the system (with respect to random assignment of radio-heads).