A Bound Based Method for Beamformer Design in Downlink Cloud Radio Access Networks

Kadan F. E. , YILMAZ A. Ö.

IEEE COMMUNICATIONS LETTERS, vol.25, no.10, pp.3350-3354, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 25 Issue: 10
  • Publication Date: 2021
  • Doi Number: 10.1109/lcomm.2021.3100271
  • Page Numbers: pp.3350-3354
  • Keywords: Interference, Signal to noise ratio, Channel estimation, Upper bound, Search problems, Data transfer, Baseband, C-RAN, convex optimization, heuristic search, norm approximation, semi-definite relaxation, C-RAN, ROBUST, MIMO, TRANSMISSION, ALLOCATION


Cloud Radio Access Network is a candidate solution in 5G and beyond where we intend to serve as many users as possible with minimum transmit power and minimum fronthaul data transmission. In this study, we aim to maximize a mixed expression of the number of users served, the number of fronthaul links used, and the total transmitted power by beamforming optimization under imperfect channel state information. We find a theoretical upper bound and propose a method based on the bound derivation. We compare its performance with heuristic search and norm approximation methods solving a series of convex sub-problems. The detailed simulations show that the proposed method outperforms other baseline techniques in terms of the number of users served, fronthaul data rate, power consumption, and computational complexity.