Joint Designs of Fronthaul Compression and Precoding for Full-Duplex Cloud Radio Access Networks

Abstract

This letter studies a joint design of fronthaul compression and precoding for full-duplex (FD) cloud radio access networks (C-RAN). In this system, each radio unit (RU) takes the role of FD transmission and a control unit connected to all of the RUs via finite-capacity links performs co-operative interference management by centralized baseband processing. There exists non-negligible self-interference (SI) due to FD transmission even after analog SI cancellation (SIC) is applied at the RU. To efficiently alleviate the residual SI, we propose the implementation of additional digital SIC at each RU, which mitigates the SI in baseband and thus reduces the burden of the finite uplink fronthaul capacity. We then consider the problem of maximizing the sum rate of uplink and downlink users while satisfying the per-RU fronthaul capacity and power constraints. The problem is solved by the majorization minimization approach under a difference of convex structure. Through simulation results, we confirm that the proposed FD C-RAN system with SIC implemented at the RUs can achieve substantial gains compared to conventional schemes.