Practical feasibility, scalability and effectiveness of coordinated scheduling algorithms in cellular networks towards 5G

Coordinated Scheduling (CS) is used to mitigate inter-cell interference in present (4G) and future (5G) cellular networks. We show that coordination of a cluster of nodes can be formulated as an optimization problem, i.e., placing the Resource Blocks (RB) in each node’s subframe with the least possible over-lapping with neighboring nodes. We provide a clever formulation, which allows optimal solutions to be computed in clusters of ten nodes, and algorithms that compute good suboptimal solutions for clusters of tens of nodes, fast enough for a network to respond to traffic changes in real time. This allows us to assess the relationship between the scale at which CS is performed and its benefits in terms of network energy efficiency and cell-edge user rate. Our results, obtained using realistic power, radiation and Signal-to-Interference-and-Noise-Ratio (SINR) models, show that optimal CS allows a significant protection of cell-edge users. Moreover, this goes hand-in-hand with a reduction in the num-ber of allocated RBs, which in turn allows an operator to reduce its energy consumption. Both benefits actually increase with the size of the clusters. The evaluation is carried out in both a 4G and a foreseen 5G setting, using different power models, system bandwidths and SINR-to-datarate mappings

Minimizing power consumption in virtualized cellular networks

Cellular network nodes should be dynamically switched on/off based on the load requirements of the network, to save power and minimize inter-cell interference. This should be done keeping into account global interference effects, which requires a centralized approach. In this paper, we present an architecture, realized within the Flex5GWare EU project, that manages a large-scale cellular network, switching on and off nodes based on load requirements and context data. We describe the architectural framework and the optimization model that is used to decide the activity state of the nodes. We present simulation results showing that the framework adapts to the minimum power level based on the cell loads

On Performance Analysis of Single Frequency Network with C-RAN

Centralized-RAN (C-RAN) is an architectural trend that uses resource sharing and a set of interference mitigation techniques to reduce capital and operational expenditures for mobile network operators (MNOs). One of the technical enablers of a C-RAN solution is single frequency network (SFN) that curbs the interference and allows MNOs to transmit over single frequency across coordinated cells. One of the main advantages of SFN is that it reduces the number of handovers between neighboring cells while improving the overall system performance. In contrast to previous approaches that demonstrate some of the most prominent C-RAN features, in this paper, we first investigate two different SFN deployment scenarios’ characteristics, benefits, and limitations. Second, we perform a simulation analysis of non-SFN and SFN without joint scheduling to observe signal to interference ratio heatmap distribution of the experimental test-site using similar system configurations. Finally, we perform an experimental analysis of joint scheduling in SFN based on coordinated inter baseband units scenario using C-RAN in a realistic environment. The experimental results are tested on a real operating site of a major MNO’s infrastructure in Turkey. Through experimental results, we show overall performance gains of SFN feature in terms of different key performance indicators that are obtained from coordinating remote radio units in an SFN cell. Finally, we discuss about the main takeaways, lessons learned, and challenges of the considered SFN implementation

Evolution Toward 5G Mobile Networks - A Survey on Enabling Technologies

In this paper, an extensive review has been carried out on the trends of existing as well as proposed potential enabling technologies that are expected to shape the fifth generation (5G) mobile wireless networks. Based on the classification of the trends, we develop a 5G network architectural evolution framework that comprises three evolutionary directions, namely, (1) radio access network node and performance enabler, (2) network control programming platform, and (3) backhaul network platform and synchronization. In (1), we discuss node classification including low power nodes in emerging machine-type communications, and network capacity enablers, e.g., millimeter wave communications and massive multiple-input multiple-output. In (2), both logically distributed cell/device-centric platforms, and logically centralized conventional/wireless software defined networking control programming approaches are discussed. In (3), backhaul networks and network synchronization are discussed. A comparative analysis for each direction as well as future evolutionary directions and challenges toward 5G networks are discussed. This survey will be helpful for further research exploitations and network operators for a smooth evolution of their existing networks toward 5G networks