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IEEE 1914 NGFI (xhaul): efficient and scalable fronthaul transport for 5G


MTI gave a keynote presentation, representing IEEE 1914 NGFI, at BackNets workshop to show progress on xhaul transport standardization.

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Radio over Ethernet demonstration


Abstract: 5G mobile fronthaul is envisioned to be packet-based, utilizing main stream transport technologies like Ethernet. Radio over Ethernet (RoE) is a Standard for Radio over Ethernet Encapsulations and Mappings developed under IEEE 1914.3 working group, which is a part of IEEE 1914 Next Generation Fronthaul Interface (NGFI) task force. RoE enables transport of native IQ data over Ethernet (Native RoE packet mapper), as well as supports structure-aware mappers and structure-agnostic mapper for CPRI/OBSAI and other data formats. In this way legacy, e.g. Long Term Evolution (LTE) equipment can be flexibly included in Ethernet-based fronthaul.
In this whitepaper we present a demonstration of RoE using a native time domain mapper. It can be flexibly used in 5G and 4G deployments, for Cloud (or Centralized) Radio Access Network (C-RAN) architecture, as well as for base stations architecture with Remote Radio Head (RRH) and non-centralized Baseband Unit (BBU).

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Fronthaul dimensioning tool


Probably everyone working on fronthaul for 5G networks needs to calculate throughput requirements for different functional splits. MTI prepared a Fronthaul Dimensioning Tool and shares it in a form of an open source tool. It is based on LTE air interface and can be updated when 5G New Radio (NR) parameters will enter into 3GPP standards.
This tool is our contribution to IEEE 1914 Next Generation Fronthaul Interface (NGFI) working group to facilitate definition of data rates required for 5G fronthaul.

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Cloud RAN for Mobile Networks – a Technology Overview


Abstract: Cloud Radio Access Network (C-RAN) is a novel mobile network architecture which can address a number of challenges the operators face while trying to support growing end-user’s needs. The main idea behind C-RAN is to pool the Baseband Units (BBUs) from multiple base stations into centralized BBU Pool for statistical multiplexing gain, while shifting the burden to the high-speed wireline transmission of In-phase and Quadrature (IQ) data. C-RAN enables energy efficient network operation and possible cost savings on baseband resources. Furthermore, it improves network capacity by performing load balancing and cooperative processing of signals originating from several base stations. This article surveys the state-of-the-art literature on C-RAN. It can serve as a starting point for anyone willing to understand C-RAN architecture and advance the research on C-RAN.
This article was published in IEEE Communications Surveys & Tutorials (Volume: 17, Issue: 1, Firstquarter 2015)

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Evaluating C-RAN fronthaul functional splits in terms of network level energy and cost savings


Abstract: The placement of the complete baseband processing in a centralized pool results in high data rate requirement and inflexibility of the fronthaul network, which challenges the energy and cost effectiveness of the Cloud Radio Access Network (C-RAN). Recently, redesign of the C-RAN through functional split in the baseband processing chain has been proposed to overcome these challenges. This paper evaluates, by mathematical and simulation methods, different splits with respect to network level energy and cost efficiency having in the mind the expected quality of service.
The proposed mathematical model quantifies the multiplexing gains and the trade-offs between centralization and decentralization concerning the cost of the pool, fronthaul network capacity and resource utilization. The event-based simulation captures the influence of the traffic load dynamics and traffic type variation on designing an efficient fronthaul network.
Based on the obtained results, we derive a principle for fronthaul dimensioning based on the traffic profile. This principle allows for efficient radio access network with respect to multiplexing gains while achieving the expected users’ quality of service.
This article was published in Journal of Communications and Networks (Volume: 18, Issue: 2, April 2016)

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Enhancing LTE with Cloud-RAN and Load-Controlled Parasitic Antenna Arrays


Abstract: Cloud radio access network (C-RAN) systems consisting of remote radio heads (RRHs) densely distributed in a coverage area and connected by optical fibers to a cloud infrastructure with large computational capabilities, have the potential to meet the ambitious objectives of next generation mobile networks. Actual implementations of C-RANs tackle fundamental technical and economic challenges. In this article, we present an end-to-end (E2E) solution for practically implementable C-RANs by providing innovative solutions to key issues such as the design of cost-effective hardware and power-effective signals for RRHs, efficient design and distribution of data and control traffic for coordinated communications and conception of a flexible and elastic architecture supporting dynamic allocation of both the densely distributed RRHs and the centralized processing resources in the cloud to create virtual base-stations (BSs). More specifically, we propose a novel antenna array architecture called load-controlled parasitic antenna array (LCPAA) where multiple antennas are fed by a single RF chain. Energy and spectral-efficient modulation as well as signaling schemes that are easy to implement are also provided. Additionally, the design presented for the fronthaul (FH) enables flexibility and elasticity in resource allocation to support BS virtualization. A layered-design of information control for the proposed E2E solution is presented. The feasibility and effectiveness of such LCPAA-enabled C-RAN system setup has been validated through an over-the-air (OTA) demonstration.
This article was published in IEEE Communications Magazine (Volume: 54, Issue: 12, December 2016)

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Optimizing small cell deployment by the use of C-RANs


Abstract: A Cloud Radio Access Network (C-RAN) is a novel mobile network architecture that has the potential to support extremely dense mobile network deployments enhancing the network capacity while offering cost savings on baseband resources. In this work we analyze cell traffic profiles and evaluate the conditions that impact the statistical multiplexing gain in the Baseband Unit (BBU) Pool. We conclude on the set of parameters that maximize the statistical multiplexing gain, leading to the highest potential cost savings. We then propose a packet based architecture that can adapt to changing traffic conditions. Furthermore, based on theoretical calculations and network simulations we present considerations on deployment scenarios to optimize green field deployments in terms of Total Cost of Ownership (TCO). This involves optimizing the mix of cells with different traffic profiles and the BBU Pool positioning in order to reduce the number of required BBUs as well as the required fiber.
This article was published in proceedings of European Wireless 2014 – 20th European Wireless Conference

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Synchronization Challenges in Packet-based Cloud-RAN Fronthaul for Mobile Networks


Abstract: In this paper, we look at reusing existing packet-based network (e.g. Ethernet) to possibly decrease deployment costs of fronthaul Cloud Radio Access Network (C-RAN) network and cost of Baseband Unit (BBU) resources. The challenge of this solution is that it requires mobile traffic (until now transmitted over synchronous protocols) to traverse the asynchronous Ethernet without losing synchronization. We analyze synchronization requirements of mobile networks and present an overview of solutions that fulfill them in traditional mobile networks. Then we elaborate on challenges that packet-based fronthaul imposes. We analyze possible contributions to frequency and phase error. We verify the feasibility of using the IEEE 1588v2 also know as Precision Time Protocol (PTP) for providing accurate phase and frequency synchronization. The study is based on simulations made in OPNET modeler. Thereby we bridge the gap between Ethernet and mobile network domains creating a comprehensive architectural analysis.
This article was published in Communication Workshop (ICCW), 2015 IEEE International Conference on

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MTI Radiocomp & Altera White Paper: OTN Transport of Baseband Radio Serial Protocols in C-RAN Architecture for Mobile Network Applications


Abstract: This white paper presents a proof of concept implementation of digital baseband radio data transport over Optical Transport Network (OTN) compliant to 3GPP Long Term Evolution – Advanced (LTE-A) standard enabling Cloud Radio Access Network (C-RAN) architecture. The transport between the baseband module and a remote radio module is compliant to Common Public Radio Interface (CPRI) and to the OBSAI reference point 3 – 01 (RP3-01) interface protocols, respectively. The purpose is to demonstrate that data integrity and clocking performance at the radio node still meets the strict standard requirements after CPRI and OBSAI transport over an OTN.

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MTI Radiocomp & Altera White Paper: Remote Radio Heads and the Evolution to 4G Networks


Abstract: Distributed base stations with remote radio head (RRH) capability greatly help mobile operators to resolve cost, performance, and efficiency challenges when deploying new base stations on the road to fully developed 4G networks. Multi-mode radios capable of operating according to GSM, HSPA, LTE, and WiMAX standards and advanced software configurability are key features in the deployment of more flexible and energy-efficient radio networks. This white paper describes the key market and technology requirements for RRHs and how Radiocomps state-of-the-art WiMAX/LTE RRH and intellectual property (IP) core solutions, combined with latest FPGA technology from Altera, helps design compact, green, and full-featured applications for mobile network solutions.

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MTI Radiocomp Technical Article: OBSAI RP3-01 6.144 Gbps Implementation


Abstract: A cost-efficient digital hardware implementation for high speed RP3-01 serial interface at 6.144 Gbps is presented for an OBSAI compliant BTS systems. Such data rate represents a 8x increment of the lowest RP3-01 rate and it enables transmission of multiple wideband carriers, to be used across multi-node RRH network infrastructures and across a wide range of wireless standards, including WiMAX 802.16e-2005 and 3GPP LTE wireless applications. The implementation is based on Altera EP2SGX90FF1508 FPGA device, which transceivers handles the electrical physical layer. The optical physical layer is implemented by Finisar SFP+ FTLX8571D3BCL devices. The upper layers of the RP3-01 protocol stack are implemented using Radiocomp’s OBSAI RP3-01 IP core. This implementation is backward compatible with the existing RP3-01 line rates and the design methodology of the IP core makes it usable as well on lower cost FPGA families. The FPGA design flow used is based on Altera Quartus II 7.2 programming environment for simulations, synthesis and mapping into the target device. The system’s performance is evaluated both with internal BER counters with PRBS-23 data representing valid RP3-01 traffic as well as with eye mask compliance using Agilent
86105 DCA for measurement.

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MTI Radiocomp OBSAI & CPRI Tutorial & Primer


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