Chia-Yu Chang

Impact of packetization and functional split on C-RAN fronthaul performance

Cloud-RAN (CRAN) is considered as one key enabler for beyond 4G networks, offering multiplexing gains, and advanced cooperation and coordinated signal processing. However, a key obstacle in the adoption of the CRAN architecture is that it requires very high capacity and low latency fronthaul (FH) links to carry raw I/Q samples between remote radio heads (RRH) and the baseband units (BBUs). These capacity requirements could be reduced by a more flexible split of baseband processing between BBUs and RRHs. Nevertheless, while moving some of the processing back into the RRH is expected to reduce FH rates, the amount of reduction mainly depends on the split, cell load, scenario and it might also introduce some delays. To this end, this paper studies the impact of different functional splits on the FH capacity for representative scenarios. Furthermore, we propose the use of a packet-based fronthaul network and study the joint impact of different packetization methods and RRH-BBU functional splits on the FH rate and latency. Based on this study, we provide some insights on the feasibility and optimality of different combinations, and the potential multiplexing benefits in terms of numbers of RRHs one could support over a single Ethernet-based FH network.

MEC architectural implications for LTE/LTE-A networks

Towards 5G mobile networks, the low-latency and high-bandwidth services are highly anticipated; however, legacy 3G and 4G networks now suffers from the mobile data surge. In this sense, pushing network services to the network edge has the potential to improve the traffic latency, user experience, and offload Internet traffic. Although the LTE/LTE-A network can highly benefit from the Mobile Edge Computing (MEC) principle, a detailed MEC architecture is not currently in place. In this work, we propose a modular architecture for the Mobile Edge Host that is ETSI compliant and describe the functional mapping of the architecture to LTE systems. Proof-of-concept demonstrations based on the OpenAirInterface (OAI), a software implementation of LTE/LTE-A systems, present significant benefits of adopting the MEC concept in data caching use case.

Impact of Packetization and Scheduling on C-RAN Fronthaul Performance

Being considered as a key enabler for beyond 4G networks, Cloud-RAN (CRAN) offers advanced cooperation and coordinated processing capabilities and brings multiplexing gains. The high capacity and low latency fronthaul (FH) links requirement in the CRAN architecture can be reduced by a ?exible functional split of baseband processing between remote radio units (RRUs) and Baseband units (BBUs). Under the wide adoption of Ethernet in data centers and the core network, we consider the Radio over Ethernet (RoE) as an off- the-shelf alternative for FH link in this work. Moreover, the packetization process that packs each sample into Ethernet packets transported over the FH link will impact the CRAN performance. To this end, we investigate the impact of packetization on the proposed CRAN network and provide a packetization algorithm over the FH links. Furthermore, we also survey and analyze various packet scheduling policies applied at the aggregated RRU gateway in order to increase the multiplexing gain. Finally, the simulation results provide more in-depth insights on the potential multiplexing gains in terms of the maximum number of RRUs that can be supported over the Ethernet- based FH network.

FlexCRAN: A flexible functional split framework over ethernet fronthaul in Cloud-RAN

Thorough investigation of the Cloud-RAN (C-RAN) architecture has recently shown that C-RAN can bring advanced cooperated and coordinated processing capabilities as well as the multiplexing gains toward future radio access networks. The baseband processing of each base station instance can now be flexibly split into smaller functional components, that can be placed either at remote radio units (RRUs) or baseband units (BBUs), depending on the available fronthaul (FH) performance. Additionally, with the wide adoption of Ethernet in data centers and core networks, the Radio over Ethernet (RoE) approach is now considered as an off-the-shelf candidate for the FH link. To this end, we propose a unified RRU/BBU architectural framework for C-RAN that can support both a flexible functional split and a FH transport protocol over Ethernet. Furthermore, we experimentally evaluate the main key performance indicators (KPIs) of an operational C-RAN network built based on OpenAirInterface (OAI), a software implementation of LTE/LTE-A systems, under two functional splits and different deployment scenarios.

Improving the efficiency and reliability of wearable based mobile eHealth applications

Abstract In this paper we address the support of wearable mHealth applications in LTE and future 5G networks following a holistic approach that spans across the elements of a mobile network. The communication requirements change from one application to another so we propose a measurement methodology to facilitate the selection of the user equipment to fulfil these requirements. We also discuss a new network architecture to support traffic prioritization, RAN programmability, low latency and group communications to over-the-top applications. Our proposal is validated using several realistic experimentation platforms and the results show that mHealth systems can benefit from our approach.

Scenarios for 5G networks: The COHERENT approach

Efficient coordination among network elements and optimal resource utilization in heterogeneous mobile networks (HMNs) is a key factor for the success of future 5G systems. The COHERENT project focuses on developing an innovative programmable control and coordination framework which is aware of the underlying network topology, radio environment and traffic conditions, and can efficiently coordinate available spectrum resources. In this paper, we provide a set of scenarios and use cases that the COHERENT project intends to address.

Plug & Play Network Application Chaining for Multi-Service Programmability in 5G RAN

RAN slicing is one of the key enabler to enable virtualization of a BS and its delivery as a service with different levels of network isolation and sharing so as to accommodate the needs of mobile network operators and verticals. In this demonstration, we show a prototype of a RAN slicing runtime system to enable flexible slice customization on the top of a disaggregated RAN infrastructure [1] with different levels of isolation and sharing in terms of resources and network functions, while retaining the quality of service (QoS) for different slice instances. Furthermore, a novel plug & play network application chaining framework empowered by a network software development kit (SDK) is demonstrated to show how the multi-service programmability on per-slice basis can be achieved. Our demonstration is based on the OpenAirlnterface [3], Mosaic-5G FlexRAN [4] and LL-MEC [2] platforms. Finally, we highlight how the the proposed approach can be extended to an end-to-end network slicing scenario.

Autonomous Self-Backhauled LTE Mesh Network With QoS Guarantee

Public safety communication systems are currently evolving due to emergence of long term evolution (LTE) as a mature solution to replace the legacy ones while providing new services. However, LTE is initially designed for commercial cellular network and needs to be furthermore evolved to tackle the substantial requirements of public safety use cases. For instance, opportunistic deployments require modifications to enable the autonomous operation and meshing of moving base stations while satisfying heterogeneous frequency band availability. In this article, we present a novel radio access network infrastructure architecture that enables multi-hop LTE mesh networking for nomadic and autonomous base stations via in-band self-backhauling. Furthermore, we investigate the coordination and orchestration functionality within the proposed architecture and propose a hierarchical resource scheduling algorithm in order to efficiently meet quality of service (QoS) requirements for real-time traffic while maximizing the throughput for elastic flows. To demonstrate the feasibility and reliability of our proposed architecture, we implement the corresponding self-backhauling air-interface based on OpenAirInterface platform and compare it with the legacy LTE air-interface. Finally, we evaluate the efficiency and adaptability of our proposed resource scheduling algorithm in various network topology and heterogeneous traffic flows with QoS requirements.

Mosaic5G: Agile and flexible service platforms for 5G research

Network slicing is one of the key enablers to provide the required flexibility and to realize the service-oriented vision toward fifth generation (5G) mobile networks. In that sense, virtualization, softwarization, and disaggregation are core concepts to accommodate the requirements of an end-to-end (E2E) service to be either isolated, shared, or customized. They lay the foundation for a multi-service and multi-tenant architecture, and are realized by applying the principles of software-defined networking (SDN), network function virtualization (NFV), and cloud computing to the mobile networks. Research on these principles requires agile and flexible platforms that offer a wide range of real-world experimentations over different domains to open up innovations in 5G. To this end, we present Mosaic5G, a community-led consortium for sharing platforms, providing a number of software components, namely FlexRAN, LL-MEC, JOX and Store, spanning application, management, control and user plane on top of OpenAirInterface (OAI) platform. Finally, we show several use cases of Mosaic5G corresponding to widely-mentioned 5G research directions.

Self-backhauled autonomous LTE mesh networks

Reliable service provisioning is crucial to the public safety (PS) communications especially when network outage happens. Isolated E-UTRAN operation, introduced in LTE Release 13, is able to host separate core network functions at the base stations (BSs) to provide limited set of services to the users. However, a significant issue remains to be solved is to coordinate among BSs to create an autonomous network and enhance service availability and reliability. In this paper, an in-band LTE self-backhauling operation leveraging the relay interface is proposed to create an autonomous mesh network of BSs. This calls for an efficient resource allocation for multiple unplanned backhaul links between BSs. To this end, we present a cross-layer scheduling problem for in-band self-backhauled LTE network, and provide a interference-aware hierarchical resource allocation algorithm that is able to meet specific quality of service (QoS) requirements for real-time traffic while adapting to the workload of other types of traffic, through efficient leverage of FDD capabilities and network frequency re-use. Finally, a thorough evaluation on our proposed approach is realized via extensive simulations on different network topologies and diverse traffic flows, and the results demonstrate our work effectiveness utilization of available resources to satisfy QoS requirements.