413 research outputs found
Energy Efficient Resource Allocation Optimization in Fog Radio Access Networks with Outdated Channel Knowledge
Fog Radio Access Networks (F-RAN) are gaining worldwide interests for
enabling mobile edge computing for Beyond 5G. However, to realize the future
real-time and delay-sensitive applications, F-RAN tailored radio resource
allocation and interference management become necessary. This work investigates
user association and beamforming issues for providing energy efficient F-RANs.
We formulate the energy efficiency maximization problem, where the F-RAN
specific constraint to guarantee local edge processing is explicitly
considered. To solve this intricate problem, we design an algorithm based on
the Augmented Lagrangian (AL) method. Then, to alleviate the computational
complexity, a heuristic low-complexity strategy is developed, where the tasks
are split in two parts: one solving for user association and Fog Access Points
(F-AP) activation in a centralized manner at the cloud, based on global but
outdated user Channel State Information (CSI) to account for fronthaul delays,
and the second solving for beamforming in a distributed manner at each active
F-AP based on perfect but local CSIs. Simulation results show that the proposed
heuristic method achieves an appreciable performance level as compared to the
AL-based method, while largely outperforming the energy efficiency of the
baseline F-RAN scheme and limiting the sum-rate degradation compared to the
optimized sum-rate maximization algorithm
Fronthaul-Constrained Cloud Radio Access Networks: Insights and Challenges
As a promising paradigm for fifth generation (5G) wireless communication
systems, cloud radio access networks (C-RANs) have been shown to reduce both
capital and operating expenditures, as well as to provide high spectral
efficiency (SE) and energy efficiency (EE). The fronthaul in such networks,
defined as the transmission link between a baseband unit (BBU) and a remote
radio head (RRH), requires high capacity, but is often constrained. This
article comprehensively surveys recent advances in fronthaul-constrained
C-RANs, including system architectures and key techniques. In particular, key
techniques for alleviating the impact of constrained fronthaul on SE/EE and
quality of service for users, including compression and quantization,
large-scale coordinated processing and clustering, and resource allocation
optimization, are discussed. Open issues in terms of software-defined
networking, network function virtualization, and partial centralization are
also identified.Comment: 5 Figures, accepted by IEEE Wireless Communications. arXiv admin
note: text overlap with arXiv:1407.3855 by other author
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