Statistically Sound Experiments with OpenAirInterface Cloud-RAN Prototypes

Research on 4G/5G cellular networks is progressively shifting to paradigms that involve virtualization and cloud computing. Within this context, prototyping assumes a growing importance as a performance evaluation method, besides large-scale simulations, as it allows one to evaluate the computational requirements of the system. Both approaches share the need for a structured and statistically sound experiment management, with the goal of reducing errors in both planning and measurement collection. In this paper, we describe how we solve the problem with OpenAirInterface (OAI), an open-source system for prototyping 4/5G cellular networks. We show how to integrate a sound, validated software, namely ns2-measure, with OAI, so as to enable harvesting samples of arbitrary metrics in a structured way, and we describe scripts that allow structured experiment management, such as launching a parametric simulation campaign and harvesting its results in a plot-ready format. We complete the paper by demonstrating some advantages brought about by our modifications

Coordinated scheduling in a Virtual-RAN prototype with OpenAirInterface

The virtualized Radio Access Network (V-RAN) is a key technology for 5G networks. In this paper we present a live prototype of Virtual RAN implementing a Coordinated Scheduling algorithm enforced by a centralized coordinator. The 5G proof of concept, devised to improve the usage of radio resource and efficiency, is realized by exploiting open-source software to fully virtualize the LTE eNodeBs, and accommodates commercial terminals. We implemented two coordination algorithms: a simple static one for testing purposes, and a dynamic one appeared in [1]. Preliminary results show that coordination actually isolates the eNodeBs, reducing inter-cell interference

A testbed for flexible and energy-efficient resource management with virtualized LTE-A nodes

This paper describes the software architecture and the implementation of a fully operational testbed that demonstrates the benefits of flexible, dynamic resource allocation with virtualized LTE-A nodes. The testbed embodies and specializes the general software architecture devised within the Flex5Gware EU project, and focuses on two intelligent programs: the first one is a Global Scheduler, that coordinates radio resource allocation among interfering nodes; the second one is a Global Power Manager, which switches on/off nodes based on their expected and measured load over a period of minutes. The software framework is written using open-source software, and includes fast, scalable optimization algorithms at both components. Moreover, it supports virtualized BaseBand Units, implemented using OpenAir-Interface, that can run on physical and virtual machines. We present the results obtained via on-field measurements, that demonstrate the feasibility and benefits of our approach

Flexible dynamic Coordinated Scheduling in Virtual-RAN deployments

Using Coordinated Scheduling (CS), eNodeBs in a cellular network dynamically agree on which Resource Blocks (not) to use, so as to reduce the interference, especially for celledge users. This paper describes a software framework that allows dynamic CS to occur among a relatively large number of nodes, as part of a more general framework of network management devised within the Flex5Gware project. The benefits of dynamic CS, in terms of spectrum efficiency and resource saving, are illustrated by means of simulation and with live measurements on a prototype implementation using virtualized eNodeBs

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