xHaul Technology and Economics (macro-cell centric)

2016 IEEE International Conference on Communications Workshops (ICC), 2016

Cloud-RAN (C-RAN) is considered a prime enabler to 5G with promising resource pooling gains, tighter coordination among cells, and cost saving in remote radio heads and corresponding deployment and operation. However, C-RAN brings stringent requirements on the backhaul last mile, or the fronthaul, in terms of capacity, latency, and synchronisation, to the extent that direct fibre is believed to be the only plausible fronthaul solution. Knowing that more often than not, fibre to the home is not available and is a cumbersome and costly technology to provide, what are the alternatives for deploying C-RAN? How much loss is incurred in a 5G network if C-RAN is not available? On the other hand, the distributed RAN (D-RAN) is less demanding on the backhaul but is believed to lack in performance in terms of resource usage and efficiency of RAN deployment. In this work we address the comparison between C-RAN and D-RAN from a joint RAN and backhaul perspective in a quantitative manner, using a case study approach. Our results show that C-RAN is indeed cost effective and advantageous from a joint perspective; moreover, intermediate functional splits between the C-RAN and the D-RAN are promising as an evolution path towards 5G, in the absence of fibre.

EURASIP Journal on Wireless Communications and Networking, 2017

To meet the requirements of 5G mobile networks, several radio access technologies, such as millimeter wave communications and massive MIMO, are being proposed. In addition, cloud radio access network (C-RAN) architectures are considered instrumental to fully exploit the capabilities of future 5G RANs. However, RAN centralization imposes stringent requirements on the transport network, which today are addressed with purpose-specific and expensive fronthaul links. As the demands on future access networks rise, so will the challenges in the fronthaul and backhaul segments. It is hence of fundamental importance to consider the design of transport networks alongside the definition of future access technologies to avoid the transport becoming a bottleneck. Therefore, we analyze in this work the impact that future RAN technologies will have on the transport network and on the design of the next generation fronthaul interface. To understand the especially important impact of varying user traffic, we utilize measurements from a real-world 4G network and, taking target 5G performance figures into account, extrapolate its statistics to a 5G scenario. With this, we derive both per-cell and aggregated data rate requirements for 5G transport networks. In addition, we show that the effect of statistical multiplexing is an important factor to reduce transport network capacity requirements and costs. Based on our investigations, we provide guidelines for the development of the 5G transport network architecture.

IEEE Wireless Communications, 2015

Optical Switching and Networking, 2018

C-RAN is an architecture for future 5G cellular networks, which has the potential of combining emerging technologies from both the wireless and the Information Technology (IT) industries by incorporating cloud computing into Radio Access Networks (RANs). This paper presents a comprehensive review of the transport options for constructing mobile fronthaul, capable of supporting applications and services beyond LTE advanced. The architecture of C-RAN is first studied which comprises mobile backhaul, mobile fronthaul and the User Equipment (UE). Then, it describes the different fronthaul transport options that are capable to the drastic increase of wireless bandwidth as well as the massive deployment of small cells. It also numerically evaluated the End to End (E2E) latency, the maximum possible separation distance between Remote Radio Head (RRH) and Base Band Unit (BBU), and Packet Delay Variation (PDV) of the mobile fronthaul solutions with emphasis on Ethernet network. Moreover, the paper explains Ethernet frame format for transporting Radio over Ethernet (RoE) traffic. Finally, the paper presents a summary of emerging research directions, opportunities and challenges in optical networking in mobile fronthual networks.

The Radio Access Network (RAN) architecture evolves with different generations of mobile communication technologies and forms an indispensable component of the mobile network architecture. The main component of the RAN infrastructure is the base station, which includes a Radio Frequency unit and a baseband unit. The RAN is a collection of base stations connected to the core network to provide coverage through one or more radio access technologies. The advancement towards cloudnative networks has led to centralizing the baseband processing of radio signals. There is a trade-off between the advantages of RAN centralization (energy efficiency, power cost reduction, and the cost of the fronthaul) and the complexity of carrying traffic between the data processing unit and distributed antennas. 5G networks hold high potential for adopting the centralized architecture to reduce maintenance costs while reducing deployment costs and improving resilience, reliability, and coordination. Incorp...

IEEE Transactions on Mobile Computing

In addition to CPRI, new functional splits have been defined in 5G creating diverse fronthaul transport bandwidth and latency requirements. These fronthaul requirements shall be fulfilled simultaneously together with the backhaul requirements by an integrated fronthaul and backhaul transport solution. In this paper, we analyze the technical challenges to achieve an integrated transport solution in 5G and propose specific solutions to address these challenges. These solutions have been implemented and verified with pre-commercial equipment. Our results confirm that an integrated fronthaul and backhaul transport dubbed Crosshaul can meet all the requirements of 5G fronthaul and backhaul in a cost-efficient manner.

Microprocessors and Microsystems, 2017

Mobile networks are subject to an explosive increase in data traffic, in a context of continuous mobility and more stringent levels of QoS, which imposes demanding requirements to telecommunication networks. To cope with this trend, a novel paradigm of radio access networks, known as C-RAN, is being developed, where the physical layer processing is also shifted from the edges of the network to a centralized location. C-RAN provides important benefits and will be one of the cornerstones of 5G communication systems. However, some architectural and implementation tradeoffs need to be further evaluated. Moreover, the modularity and extensibility of research platforms supporting C-RAN is still very restrictive. This paper presents a laboratorial platform aimed for the development and trial of C-RAN compliant features. The proposed testbed is very modular and flexible and it is intended to provide a cost-effective emulation and physical layer implementation platform for the main C-RAN modules, namely the BBU, the fronthaul and the RRHs. Based on open FPGA platforms, it features a high level of flexibility in terms of configurations, waveforms and interfaces, and includes all the components required to build an open and complete C-RAN compliant base station. It is mainly used for the experimentation and evaluation of next generation wireless communication systems, including new fronthaul protocols and interfaces as well as 5G waveforms. It integrates a 25 km optical fronthaul, a software defined multi-mode and multi-band RF front-end and a digital radio compression algorithm associated with the optical fronthaul. The inclusion of low-latency (de)compression algorithms was of paramount importance in order to achieve a 50% reduction in terms of fronthaul bandwidth.

IEEE Communications Magazine, 2021

Modulation compression is a technique considered in the recent Open-RAN (O-RAN) framework, which has continued the 3GPP effort towards the definition of new virtualized and multi-vendor RAN architectures. Basically, fronthaul compression is achieved by means of reducing the modulation order, thus enabling a dramatic reduction of the required fronthaul capacity with a simple technique. In this work, we provide a survey of the architectures, functional splits, and fronthaul compression techniques envisioned in 3GPP and O-RAN. Then, we focus on assessing the trade-offs that modulation compression exhibits in terms of reduced fronthaul capacity versus the impact on the air interface performance, through a dynamic multicell system-level simulation. For that, we use an ns-3 based system-level simulator compliant with 5G New Radio (NR) specifications and evaluate different traffic load conditions and NR numerologies. In a multi-cell scenario, our results show that an 82% reduction of the required fronthaul capacity can be achieved with negligible air interface performance degradation by reducing the modulation order down to 64QAM, for different numerologies and load conditions. A higher modulation order reduction without degradation is permitted in low/medium traffic loads (reaching up to 94% fronthaul capacity reduction).

Learning Outcomes Attainment Assessment Process (G.R.Angadi), 2023

Learning outcomes are an essential part of any academic program. A learning outcome is a clear statement of what a learner is expected to be able to do, know about and/or value at the completion of an academic program of study, and how well they should be expected to achieve those outcomes. It states both the substance of learning and how its attainment is to be demonstrated. Learning outcomes not only serve the purpose of directing the content and design of an academic program of study, they form the basis of assessment and are also linked to the larger outcomes of learning set by the University in the form of Program learning Outcomes (POs), discipline-specific graduate attributes / Program Specific learning Outcomes(PSOs), Course learning Outcomes (COs). Because of their clear linkage to assessment, students will achieve the learning outcomes to differing degrees.

2018

Smart grids are slowly becoming a reality, and will soon become embedded in all aspects of society: legislation, economy, environment, etc. Voltage control and reactive power compensation are crucial for the smart grid development. This project provides a background on all these issues and focuses on determining which the best device to control voltage is. The study was carried out on the IEEE 34 Node Test Feeder using the Power Factory DIgSILENT software. It was found that StatVars, dynamic devices, keep voltage more stable and within regulated limits than capacitors, and that nodes at the end of lines or acting as sole connection for more than two segments of network, and therefore under high loading stress, are more vulnerable to voltage drops. Therfore, meshed network topologies are more favourable for stable voltage and smart grid development. Using this knowledge, smart grids will be developed. This will enable a higher penetration of renewable energies and therefore a reducti...