Joint Hybrid Backhaul and Access Links Design in Cloud-Radio Access Networks

TL;DR

This paper proposes a joint design framework for hybrid backhaul and access links in CRANs, optimizing power consumption through a two-stage heuristic algorithm that balances wireless and wireline backhaul connections.

Contribution

It introduces a novel two-stage heuristic approach for joint hybrid backhaul and access link design in CRANs, minimizing power consumption while ensuring QoS.

Findings

Performance approaches global optimum at high SINR

Efficient sparse beamforming via weighted `1=`2 norm minimization

Effective power minimization for wireless backhaul links

Abstract

The cloud-radio access network (CRAN) is expected to be the core network architecture for next generation mobile radio systems. In this paper, we consider the downlink of a CRAN formed of one central processor (the cloud) and several base-station (BS), where each BS is connected to the cloud via either a wireless or capacity-limited wireline backhaul link. The paper addresses the joint design of the hybrid backhaul links (i.e., designing the wireline and wireless backhaul connections from the cloud to the BSs) and the access links (i.e., determining the sparse beamforming solution from the BSs to the users). The paper formulates the hybrid backhaul and access link design problem by minimizing the total network power consumption. The paper solves the problem using a two-stage heuristic algorithm. At one stage, the sparse beamforming solution is found using a weighted mixed `1=`2 norm minimization approach; the correlation matrix of the quantization noise of the wireline backhaul links is computed using the classical rate-distortion theory. At the second stage, the transmit powers of the wireless backhaul links are found by solving a power minimization problem subject to quality-of-service constraints, based on the principle of conservation of rate by utilizing the rates found in the first stage. Simulation results suggest that the performance of the proposed algorithm approaches the global optimum solution, especially at high signal-to-interference-plus-noise ratio (SINR).