Backhaul Network Design Research Articles

When Resiliency Matters: An Overview of 5G and Beyond Wireless Backhaul Network Design

The massive integration of connected devices, together with the exponential growth of Internet traffic, have forced mobile network operators to continuously upgrade their infrastructures. The densification of the network, by introducing many more small cells, was promoted as a solution to meet the ongoing challenges. However, network densification implies the need for an appropriate backhaul network capable of handling the anticipated traffic. This article presents a brief overview of the wireless backhaul requirements and technologies that reinforce resiliency for next-generation networks, followed by a review of the current works on the planning of resilient wireless backhaul networks. Finally, it introduces a case study for the design of a hierarchical wireless backhaul topology that considers several basic requirements, including link reliability, network resiliency, and cost and management efficiency.

Design of survivable wireless backhaul networks with reliability considerations

The ever-increasing need for stable, seamless, high-speed connectivity places an enormous burden on the communications infrastructure, comprised of access, backhaul, and core networks. Furthermore, recent advances in access technologies shift the capacity bottleneck towards the newly popularized wireless backhaul network, which is also susceptible to different types of failures. In this paper, a wireless backhaul network design under reliability and survivability constraints is formulated as a mixed integer linear programming (MILP) model to determine the minimum cost bandwidth assignment of wireless links. We developed an accelerated Benders decomposition algorithm to solve this model. Extensive computational experiments show the accuracy of the model proposed to tackle the problem and the efficiency of the solving method, particularly in larger networks.

Traffic-aware gateway placement and queue management in flying networks

Unmanned Aerial Vehicles (UAVs) have emerged as adequate platforms to carry communications nodes, including Wi-Fi Access Points and cellular Base Stations. This has led to the concept of flying networks composed of UAVs as a flexible and agile solution to provide on-demand wireless connectivity anytime, anywhere. However, state of the art works have been focused on optimizing the placement of the access network providing connectivity to ground users, overlooking the backhaul network design. In order to improve the overall Quality of Service (QoS) offered to ground users, the placement of Flying Gateways (FGWs) and the size of the queues configured in the UAVs need to be carefully defined to meet strict performance requirements. The main contribution of this article is a traffic-aware gateway placement and queue management (GPQM) algorithm for flying networks. GPQM takes advantage of knowing in advance the positions of the UAVs and their traffic demand to determine the FGW position and the queue size of the UAVs, in order to maximize the aggregate throughput and provide stochastic delay guarantees. GPQM is evaluated by means of ns-3 simulations, considering a realistic wireless channel model. The results demonstrate significant gains in the QoS offered when GPQM is used.

Comparative Analysis of Microwave Link Using Space and Hybrid Diversity Configuration on Mountain Topography Area

The development of information and communication technology (ICT) in Indonesia is increasing rapidly every year. However, this increase is not comparable to the distribution of technology in remote areas, especially areas with mountainous contours. So it takes a proper backhaul network design to deploy telecommunication services in remote areas. Microwave transmission technology is widely used as a backhaul network in mountainous areas because it can reach areas that are difficult to reach by fiber optic. However, multipath fading becomes a problem in microwave communication, so to solve it, we use the diversity configuration approach. Space diversity configuration is the system most often used, but in more extreme conditions it can use a hybrid diversity configuration which is a combination of space and frequency diversity. In this study, we designed and compared the performance of two types of diversity configurations, namely space and hybrid diversity in cross-mountainous areas using simulation software Pathloss 5.0. Before comparison, these paths were tested with a point-to-point configuration to assess microwave communication performance without diversity. Based on the simulation, the resulting cross-mountain microwave communication performance using point-to-point configuration results in 99.98179% availability and 5742.79 seconds unavailability in one year, these values are still far from the ITU-T G.821 standard, namely 99.99% availability. In the configuration using Space Diversity, the quality has increased, but it cannot meet ITU standards because it is only capable of producing 99.98333% to 99.98943% availability or comparable to un-availability for 5255.53 to 3332.48 seconds/year. Meanwhile, the hybrid diversity configuration can produce a performance that meets ITU standards with an availability of 99.99122% or equivalent to un-availability for 2769.79 seconds per year.

Enabling technologies for low-latency service migration in 5G transport networks [Invited

The fifth generation (5G) mobile communications system is envisioned to serve various mission-critical services such as industrial automation, cloud robotics, and safety-critical vehicular communications. To satisfy the stringent end-to-end latency requirement of these services, fog computing has been regarded as a promising technology to be integrated into 5G networks, in which computing, storage, and network functions are provisioned close to end users, thus significantly reducing the latency caused in transport networks. However, in the context of fog-computing-enabled 5G networks, the high mobility feature of users brings critical challenges to satisfy the stringent quality of service requirements. To address this issue, service migration, which transmits the associated services from the current fog server to the target one to follow the users’ travel trace and keep the service continuity, has been considered. However, service migration cannot always be completed immediately and may lead to a situation where users experience a loss of service access. In this regard, low-latency service migration plays a key role to reduce the negative effects on services being migrated. In this paper, the factors that affect the performance of service migration are analyzed. To enable low-latency service migration, three main enabling technologies are reviewed, including migration strategies, low-latency, and high-capacity mobile backhaul network design, and adaptive resource allocation. Based on a summary of the reviewed technologies, we conclude that dynamic resource allocation is the worthiest one to research. Therefore, we carry out a use case, where reinforcement learning (RL) is adopted for autonomous bandwidth allocation in support of low-latency service migration in a dynamic traffic environment and evaluate its performance compared to two benchmarks. The simulation demonstrates that the RL-based algorithm is able to self-adapt to a dynamic traffic environment and gets converged performance, which has an obviously smaller impact on non-migration traffic than the two benchmarks while keeping the migration success probability high. Meanwhile, unlike the benchmarks, the RL-based method shows performance fluctuations before getting converged, which may cause unstable system performance. It calls for future research on advanced smart policies that can get convergence quickly, particularly for handling the migration of latency-sensitive services in 5G transport networks.

Self-manageable backhaul network design for rural connectivity in Sucre -Colombia

Este artículo aborda el diseño e implementación de una red de telecomunicaciones de retorno (backhaul) en la región de Sucre (Colombia) como una solución disruptiva para extender la conectividad desde la red central ubicada en el municipio de Chalán a las comunidades rurales de Chalán y Ovejas. La conectividad a Internet se entregará a través de una tecnología de telecomunicaciones inalámbrica autogestionable conocida como WiBACK, que admitirá la tecnología futura de comunicación5G. Los resultados de la investigación diseñarán la hoja de ruta y la evaluación comparativa de los escenarios de expansión de la red de acceso colombiana de banda ancha en escenarios de postconflicto

Analysis And Performance Comparison of Microwave And WiFi 802.11ac Based Backhaul For Long Term Evolution Network In Urban Area

Increasing user requirements for LTE networks, data traffic from eNodeB to core network is also increases, therefore, the recommended solution for meeting this high data traffic is to use a backhaul network design. Backhaul is the path or network used to connect eNodeB with the core network. In this research, backhaul technology used is wi-fi 802.11ac backhaul and microwave backhaul. In this study begins by collecting existing data, then perform capacity calculations to find out the number of eNodeB needed and to find out the capacity of the backhaul links to be designed, then determine the antenna height to achieve LOS conditions, then calculate the desired performance standards and calculate the backhaul network link budget on microwave and wi-fi technologies. Based on the calculation results in terms of capacity, the total user target is 90,167 users and has a throughput capacity per eNodeB of 61 Mbps. In the link-capacity calculation, the total link capacity is 427 Mbps. From the simulation results that using microwave technology, the average RSL value is -30.90 dBm, the value meets the -57 dBm threshold standard and the value of availability does not meet the standard of 99.999% because the average value obtained is 99.998095%. Whereas for wi-fi technology, the average RSL value is -39.24 dBm and meet the -72 dBm threshold standard, for the average availability value meets 99.999% standard, with a value of 100%. From the results of the two technologies, can be conclude that the wi-fi technology is more suitable for the use of backhaul network design in Ciputat Sub-district.

Hybrid Radio/Free-Space Optical Design for Next Generation Backhaul Systems

The deluge of date rate in today’s networks imposes a cost burden on the backhaul network design. Developing cost-efficient backhaul solutions becomes an exciting, yet challenging, problem. Traditional technologies for backhaul networks, including either radio-frequency (RF) backhauls or optical fibers (OF). While RF is a cost-effective solution as compared with OF, it supports the lower data rate requirements. Another promising backhaul solution is the free-space optics (FSO) as it offers both a high data rate and a relatively low cost. The FSO, however, is sensitive to nature conditions, e.g., rain, fog, and line-of-sight. This paper combines both the RF and FSO advantages and proposes a hybrid RF/FSO backhaul solution. It considers the problem of minimizing the cost of the backhaul network by choosing either OF or hybrid RF/FSO backhaul links between the base stations, so as to satisfy data rate, connectivity, and reliability constraints. It shows that under a specified realistic assumption about the cost of OF and hybrid RF/FSO links, the problem is equivalent to a maximum weight clique problem, which can be solved with moderate complexity. Simulation results show that the proposed solution shows a close-to-optimal performance, especially for reasonable prices of the hybrid RF/FSO links. They further reveal that the hybrid RF/FSO is a cost-efficient solution and a good candidate for upgrading the existing backhaul networks.

A biased random-key genetic algorithm for wireless backhaul network design

This paper describes a biased random-key genetic algorithm for a real-world wireless backhaul network design problem. This is a novel problem, closely related to variants of the Steiner tree problem and the facility location problem. Given a parameter h, we want to build a forest where each tree has at most h hops from the demand nodes, where traffic originates, to the root nodes where each tree is rooted. Candidate Steiner nodes do not have any demand but represent locations where we can install cellsites to cover the traffic and equipment to backhaul the traffic to the cellular core network. Each Steiner node can cover demand nodes within a given distance, subject to a capacity constraint. The aggregate set of constraints may make it impossible to cover or backhaul all demands. A revenue function computes the revenue associated with the total amount of traffic covered and backhauled to the root nodes. The objective of the problem is to build a forest that maximizes the difference between the total revenue and the cost associated with the installed equipment. Although we will have a forest when we consider only the backhaul links and root nodes, the addition of demand vertices can induce undirected cycles, resulting in a directed acyclic graph. We consider instances of this problem with several additional constraints that are motivated by the requirements of real-world telecommunication networks.