Bahare M. Khorsandi

The global connected cars market is growing rapidly. Novel services will be offered to vehicles, many of them requiring low-latency and high-reliability networking solutions. The Cloud Radio Access Network (C-RAN) paradigm, thanks to the centralization and virtualization of baseband functions, offers numerous advantages in terms of costs and mobile radio performance. C-RAN can be deployed in conjunction with a Multi-access Edge Computing (MEC) infrastructure, bringing services close to vehicles… Mehr anzeigen

The global connected cars market is growing rapidly. Novel services will be offered to vehicles, many of them requiring low-latency and high-reliability networking solutions. The Cloud Radio Access Network (C-RAN) paradigm, thanks to the centralization and virtualization of baseband functions, offers numerous advantages in terms of costs and mobile radio performance. C-RAN can be deployed in conjunction with a Multi-access Edge Computing (MEC) infrastructure, bringing services close to vehicles supporting time-critical applications. However, a massive deployment of computational resources at the edge may be costly, especially when reliability requirements demand deployment of redundant resources. In this context, cost optimization based on integer linear programming may result in being too complex when the number of involved nodes is more than a few tens. This paper proposes a scalable approach for C-RAN and MEC computational resource deployment with protection against single-edge node failure. A two-step hybrid model is proposed to alleviate the computational complexity of the integer programming model when edge computing resources are located in physical nodes. Results show the effectiveness of the proposed hybrid strategy in finding optimal or near-optimal solutions with different network sizes and with affordable computational effort. Weniger anzeigen

In the 5G context, new services can be designed based on service slice embedding on the network infrastructure in relation to target performance. With reference to the functional splitting approach known as xhaul, novel slicing deployment strategies for 5G are presented to provide resiliency while optimizing the use of optical and computational resources, having in mind the uRLLC service class.

Next generation fronthaul interface has been recently proposed to support different functional splitting in 5G access network. Each split option characterized by different requirements in terms of latency and bandwidth. The mapping of different functional split on the nodes of 5G access network can achieve several degrees of freedom in terms of bandwidth due to the variation of traffic during a day. This paper proposes a novel location algorithm of functions, identified in the xhaul network, to… Mehr anzeigen

Next generation fronthaul interface has been recently proposed to support different functional splitting in 5G access network. Each split option characterized by different requirements in terms of latency and bandwidth. The mapping of different functional split on the nodes of 5G access network can achieve several degrees of freedom in terms of bandwidth due to the variation of traffic during a day. This paper proposes a novel location algorithm of functions, identified in the xhaul network, to nodes which adopt dynamic function chaining in relation to the evolution of the traffic estimate. The results are
obtained show remarkable improvement in terms of bandwidth savings and multiplexing gain and suggested design criteria for the emerging 5G access network. Weniger anzeigen

Cloud radio access networks (C-RANs), relying on network function virtualization and software-defined networking (SDN), require a proper placement of baseband functionalities (BBUs) to reach full coverage of served areas and service continuity. In this context, network resources can be shared and orchestrated to meet the flexibility required by a dynamically evolving environment. Different methodologies, based on analytical formulation or heuristic algorithms, can be applied to achieve suitable… Mehr anzeigen

Cloud radio access networks (C-RANs), relying on network function virtualization and software-defined networking (SDN), require a proper placement of baseband functionalities (BBUs) to reach full coverage of served areas and service continuity. In this context, network resources can be shared and orchestrated to meet the flexibility required by a dynamically evolving environment. Different methodologies, based on analytical formulation or heuristic algorithms, can be applied to achieve suitable trade-offs among cost components. This paper considers both centralized and distributed algorithms to obtain BBU hotel placement in C-RAN and compares their performance, scalability and adaptability to evolving scenarios. As expected, the results obtained with the distributed approach are sub-optimal, but very close, in most cases, to the optimal solutions obtained with a centralized algorithm based on integer linear programming. In addition to off-loading the SDN orchestrator, the distributed approach, differently from the centralized one, is shown to be able to cope with the evolution of the C-RAN topology with limited incremental changes in the original placement. The limits of the centralized approach in terms of scalability that the distributed approach is able to overcome are also evidenced. Weniger anzeigen

Centralized/Cloud Radio Access Networks (C-RAN) are deployed in converged fixed-mobile networks to exploit the flexibility coming from joint application of Network Function Virtualization (NFV) and Software Defined Networking (SDN). In this context, optical links connecting C-RAN nodes, possibly based on the Ethernet standards, may carry traffic with different requirements in terms of latency and throughput. This paper considers the problem of traffic aggregation on C-RAN optical Ethernet links… Mehr anzeigen

Centralized/Cloud Radio Access Networks (C-RAN) are deployed in converged fixed-mobile networks to exploit the flexibility coming from joint application of Network Function Virtualization (NFV) and Software Defined Networking (SDN). In this context, optical links connecting C-RAN nodes, possibly based on the Ethernet standards, may carry traffic with different requirements in terms of latency and throughput. This paper considers the problem of traffic aggregation on C-RAN optical Ethernet links with latency control for fronthaul traffic and throughput capability for backhaul traffic. Integrated hybrid network technique is applied to show how time transparency can be enforced for Ethernet encapsulated Common Public Radio Interface (CPRI) traffic while allowing statistical multiplexing of backhaul traffic. Simulation results show the effectiveness of segmentation of backhaul traffic to allow exploitation of the available bandwidth even with high capacity CPRI options. Weniger anzeigen

Integrated hybrid optical network is investigated to carry both fronthaul and backhaul traffic on an Ethernet optical channel. Evaluation of the additional backhaul throughput is presented to demonstrate the effectiveness of the approach.

New 5G radio access network is expected to offer competitive advantages in terms of cost, quality of service and mobility, that make it attractive for service providers. The resilience of this part of the network is consequently essential to provide high availability and service continuity in case of failure. This study focuses on heuristic solutions to design and operate the fronthaul network based on the Centralized Radio Access Network (C-RAN) concept. Facility Location Algorithms (FLA) are… Mehr anzeigen

New 5G radio access network is expected to offer competitive advantages in terms of cost, quality of service and mobility, that make it attractive for service providers. The resilience of this part of the network is consequently essential to provide high availability and service continuity in case of failure. This study focuses on heuristic solutions to design and operate the fronthaul network based on the Centralized Radio Access Network (C-RAN) concept. Facility Location Algorithms (FLA) are proposed to assign primary and backup functionalities to Baseband Unit (BBU) hotels and ensure availability in case of a single BBU hotel or link failure. Sharing techniques are applied to BBU hotel ports and transport wavelengths for hl cost-efficient design. The goal is to minimize the number of active BBU hotels while providing full coverage to all Remote Radio Units (RRU). Numerical results evaluate cost in relation to main design constraints, namely the number of hops allowed to reach primary and backup BBU hotel. The number of BBU hotels is compared for different location algorithms, showing that a proposed extension of a classical FLA, by including resilience, allows obtaining the best results both in terms of BBU hotels and shared ports. However, the need for suitable trade-off between the number of BBU hotels and the required wavelengths is outlined, depending on relative costs. Weniger anzeigen

Cloud Radio Access Networks (C-RAN) are characterized by huge introduction of Network Function Virtualization (NFV) supported by software-based control of relevant functionalities within the Software Defined Network (SDN) context. Distributed location algorithms, as a practical approach to optimally locate virtual functionalities in C-RAN, are described and compared to conventional optimization techniques, with application to BBU hotel placement and extensions to dynamic evolution of C-RAN… Mehr anzeigen

Cloud Radio Access Networks (C-RAN) are characterized by huge introduction of Network Function Virtualization (NFV) supported by software-based control of relevant functionalities within the Software Defined Network (SDN) context. Distributed location algorithms, as a practical approach to optimally locate virtual functionalities in C-RAN, are described and compared to conventional optimization techniques, with application to BBU hotel placement and extensions to dynamic evolution of C-RAN configuration. Near optimal solutions and incremental adaptability to topology changes are achieved. Weniger anzeigen

Two-phase distributed machine learning algorithm is proposed for reliable BBU hotel location in C-RAN. The effectiveness of the approach in optimizing the cost, in terms of BBU hotels, hops and wavelengths, is compared with centralized ILP solution.

In centralized/cloud radio access networks (CRANs), baseband units (BBUs) are decoupled from remote radio units (RRUs) and placed in BBU hotels. In this way baseband processing resources can be shared among RRUs, providing opportunities for radio coordination and cost/energy savings. However, the failure of a BBU hotel can affect a large number of RRUs creating severe outages in the radio segment. For this reason, the design of a resilient C-RAN is imperative. In this paper, an extension of the… Mehr anzeigen

In centralized/cloud radio access networks (CRANs), baseband units (BBUs) are decoupled from remote radio units (RRUs) and placed in BBU hotels. In this way baseband processing resources can be shared among RRUs, providing opportunities for radio coordination and cost/energy savings. However, the failure of a BBU hotel can affect a large number of RRUs creating severe outages in the radio segment. For this reason, the design of a resilient C-RAN is imperative. In this paper, an extension of the facility location problem (FLP) is proposed to find the placement of BBU hotels that guarantees survivability against single hotel failure while the delay is minimized. Different strategies are proposed based on heuristic and integer linear programming (ILP) to solve the survivable BBU location problem and optimizing the sharing of backup resources. The results compare the proposed methodologies in
terms of the costs of the BBU placement by referring to different network topologies. The heuristic algorithm is shown to find solutions close to those obtained by the ILP, although evidencing different contributions that are suitably discussed. Weniger anzeigen

Centralized Radio Access Networks (C-RANs) Baseband Units (BBUs) are decoupled from Remote Radio Units (RRUs) and placed in BBU Hotels. In this way baseband processing resources can be shared among RRUs, providing opportunities for radio coordination and cost/energy savings. However, the failure of a BBU Hotel can affect a large number of RRUs creating severe outages in the radio network. For this reason, the design of a resilient C-RAN is extremely important. This paper focuses on the… Mehr anzeigen

Centralized Radio Access Networks (C-RANs) Baseband Units (BBUs) are decoupled from Remote Radio Units (RRUs) and placed in BBU Hotels. In this way baseband processing resources can be shared among RRUs, providing opportunities for radio coordination and cost/energy savings. However, the failure of a BBU Hotel can affect a large number of RRUs creating severe outages in the radio network. For this reason, the design of a resilient C-RAN is extremely important. This paper focuses on the survivable BBU Hotel placement problem in C-RANs with an optical wavelength division multiplexing (WDM) transport. We first propose an algorithm that jointly decides (i) the placement of a minimum number of BBU Hotels and (ii) solves the Routing and Wavelength Assignment (RWA) problem for the fronthaul connections, ensuring that each RRU is connected to two different BBU Hotels (i.e., one primary and one backup). Then, we present a strategy for maximizing the sharing of backup BBU ports among RRUs, with the aim of reducing the total cost of the C-RAN while guaranteeing uninterrupted service provisioning in case of single BBU Hotel failure. Simulation results show that the proposed strategy helps reducing the overall C-RAN cost. On the other hand, it becomes also evident that the sharing benefits can be maximized only in the presence of a transport network with enough wavelength resources to handle potential bottlenecks that may occur when BBU Hotels are placed quite far from RRUs. Weniger anzeigen