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intelligent Converged network consolIdating Radio and optical access aRound USer equipment.

Periodic Reporting for period 2 - iCIRRUS (intelligent Converged network consolIdating Radio and optical access aRound USer equipment.)

Reporting period: 2016-01-01 to 2016-12-31

iCIRRUS proposes an intelligent Ethernet-based fronthaul for the Radio Access Network (RAN) of 5th Generation (5G) and beyond mobile communications. The fronthaul is a core component of the cloud- or virtualized-RAN, C-RAN or vRAN, that is now seen as essential for such future mobile systems. The intelligence, enabled by the use of Ethernet and probing the resulting fronthaul network, can also enhance the operation of other, user-facing applications. In iCIRRUS, cellular-assisted device-to-device (D2D) communication is targeted, as some network functions are placed closer to users and could aid localisation, for example, as is mobile cloud computation, which again may benefit from placing functionality closer to users in the C-RAN/vRAN. Further, an aim is to examine how the intelligence gathered can be used to optimise network performance, for the fronthaul and its effect on radio performance, and for the D2D and mobile cloud operations.

Currently, there is significant industry interest in the C-RAN/vRAN concept and the requirements that 5G will place on the fronthaul. A number of industry bodies have launched initiatives to address this problem, including important standardisation moves within IEEE, ITU and 3GPP. Similarly, D2D communication has been incorporated into the latest 3GPP releases, and more is expected in future releases. Cloud computing is also known to be a major factor in considering future networks. Thus, iCIRRUS is actively pursuing ideas which are highly timely and of major significance in the development of future standards for 5G.

The iCIRRUS consortium consists of 11 partners. It has a balance between larger and smaller operators (Orange, Telekom Slovenije, Primetel), large industry (ADVA Optical Networking, Viavi Solutions, InterDigital), smaller companies (Wellness Telecom, IAF) and universities and research institutes (University of Kent, Fraunhofer-HHI, and University of Essex). This balanced consortium is able to deliver the foundational research and the liaison, the implementation of validation setups, and the liaison with standardisation and industry bodies to enhance impact.
The initial work in the iCIRRUS project focussed on obtaining a consensus for the overall system architecture. The project examined scenarios (test cases) from the METIS project and other 5G white paper proposed scenarios, but the major consideration came from the realisation that current fronthaul technology could not be simply extended to meet the requirements of 5G. Instead, a radically new approach was required. This realisation was being made independently by others. The main effort in our overall systems work package over the first 6 months of the project, was to consolidate this thinking, defining clearly that a new functional split in the fronthaul was necessary and that the split could be implemented at different points. The effect of this new split on the overall mobile system, including the D2D and mobile cloud, was considered and the challenges that it brought were identified.

The next phase of the work was the more detailed examination of these challenges. For the fronthaul, the different split point options were compared and the requirements of each, in terms of data rates and latency/delay variation requirements were outlined. Similarly, the different functional splits offered opportunities and challenges to the D2D and mobile cloud operation, and these were more closely studied. Specifications for their possible operation were made. Overall, a new flexible vRAN/fronthaul architecture with possibilities for real convergence with other types of network was formulated – this is shown in Fig.1.

The work carried out has resulted in several publications, including an invited paper on the initial Ethernet fronthaul concept. More papers have been submitted as the detailed study has commenced.
The project has made the most detailed examination of fronthaul requirements for 5G, particularly considering new functional splits and comparing their requirements. With the significant standardisation moves that have been initiated globally, there is a very large potential impact for this work. The project has certainly made itself known by presenting at a number of events, including industry panels and standards body workshops. Significant invited presentations have been forthcoming for the 2nd year, and we expect continued involvement directly and indirectly (e.g. through our external advisory board) in standards activities.

For the D2D work, a novel proposal for grouping devices that benefits from the functionally split C-RAN architecture has been made. Proposals for balancing and optimising between operations in a central cloud and those in a temporary storage in edge clouds supported in a C-RAN type network have also been made. We also participate in IEEE standardisation activity in mm-wave, multi-hop backhaul and fronthaul.
iCIRRUS logo
Figure 1