Resource allocation in heterogeneous cloud radio access networks: advances and challenges

Recent Advances in Cloud Radio Access Networks: System Architectures, Key Techniques, and Open Issues

“…An overview of channel estimation techniques recently proposed for C-RANs, giving useful guidelines on the new requirements when employing the conventional channel estimation approaches in CRANs. Radio Resource Allocation and Optimization [18] An investigation of developments in centralized approaches to resource allocation only in the special H-CRANs but not for a general C-RAN. This Article A full survey of optimization approaches to static CRRA without considering QSI and dynamic CRRA with queue-awareness in C-RANs, covering both classic approaches and game model based approaches.…”

“…To systematically show the advances in C-RANs, several survey works have been done [13]- [18]. The progress on the centralization and virtualization for C-RANs is introduced in [13], where the performances of several key technologies like uplink coordinated multiple point (CoMP) are verified, and a general purpose platform (GPP) based C-RAN test bed is built, showing almost the same performance as traditional systems.…”

“…In addition, the authors in [17] reviewed the key fronthaul compression techniques for the uplink and downlink of a C-RAN, together with simulation results to validate the performance improvement desired from the implementation of multiterminal fronthaul compression. In [18], the developments of resource allocation in heterogeneous cloud radio access networks (H-CRANs) are investigated, and three resource allocation schemes are proposed, i.e., coordinated scheduling, hybrid backhauling, and multicloud association.…”

“…Although initial efforts have been made on the survey of C-RANs, limitations exist in the previous works that the content is only related to the practical implementation and deployment aspects in [13], or only a small part of current research achievements on C-RANs are specified in [15], or only a specific topic, which is relative to H-CRANs but not the general C-RANs, is concentrated on in [18]. Considering these shortcomings and the ongoing research activities, a more comprehensive survey framework for incorporating the basics and the latest achievements on the system architecture and key techniques across different layers over the air interface seems timely and significant.…”

“…Additionally, given the extensiveness of the research area, open issues and challenges are presented to spur future investigations. The aims of this survey are to fill the research gaps found in the previous publications [13]- [18] as stated above. In this way, the contributions of this paper are fourfold as summarized below: 1) A comprehensive survey of system architectures is presented, which is divided into the architectures proposed by the industry and the architectures proposed by the academia.…”