Joint Fronthaul Link Selection and Transmit Precoding for Energy Efficiency Maximization of Multiuser MIMO-Aided Distributed Antenna Systems

Abstract

Abstract-We jointly select the fronthaul links and optimize the transmit precoding matrices for maximizing the energy efficiency of a multiuser multiple-input multiple-output aided distributed antenna system . The fronthaul link's power consumption is taken into consideration, which is assumed to be proportional to the number of active fronthaul links quantified by using indicator functions. Both the rate requirements and the power constraints of the remote access units are considered. Under realistic power constraints some of the users cannot be admitted. Hence, we formulate a two-stage optimization problem. In Stage I, a novel user selection method is proposed for determining the maximum number of admitted users. In Stage II, we deal with the energy efficiency optimization problem. First, the indicator function is approximated by a smooth concave logarithmic function. Then, a triple-layer iterative algorithm is proposed for solving the approximated energy efficiency optimization problem, which is proved to converge to the Karush-Kuhn-Tucker conditions of the smoothened energy efficiency optimization problem. To further reduce the complexity, a single-layer iterative algorithm is conceived, which guarantees convergence. Our simulation results show that the proposed user selection algorithm approaches the performance of the exhaustive search method. Finally, the proposed algorithms is capable of achieving an order of magnitude higher energy efficiency than its conventional counterpart operating without considering link selection.

Boosting Fronthaul Capacity: Global Optimization of Power Sharing for Centralized Radio Access Network

“…Fronthaul link selection and user association, which are typically investigated together with precoding [17], [18], maximize the achievable sum-rate of a C-RAN, given a fixed fronthaul capacity constraint. Furthermore, Pan et al [16] studied the joint optimization of RRU selection, user association and beamforming in the presence of imperfect channel state information (CSI).…”

Network Coding for Distributed Antenna Systems

“…The nodes that are able to decode the message from both sources form a codeword. Moreover, in this topology it is assumed that the nodes that decode either I 1 Network Coding for Distributed Antenna Systems http://dx.doi.org/10.5772/intechopen.76323…”

“…The efficient utilization of available spectrum resources has gained attention of the research community. Distributed antenna systems (DAS) are considered as one of the solutions for ensuring efficient utilization of spectral resources [1] and providing high data rates. DAS are based on a dense deployment of remote access units (RAUs) in a cellular network, thereby reducing the distance between the users and the RAUs.…”

Nonsmooth Optimization Algorithms for Multicast Beamforming in Content-Centric Fog Radio Access Networks

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