Placement of Base-Band Units (BBUs) over fixed/mobile converged Multi-Stage WDM-PONs

The convergence between fixed access networks and mobile backhauling networks is the basis of the evolution towards future Next-Generation Access Networks. Multi-Stage WDM-PONs are the ideal converged infrastructures for carrying both fixed access and mobile backhauling, because they inherit some features of WDM core/metro networks, e.g., large capacity and high transparency. Moreover, they provide support for the “BBU Hotelling” backhauling solution, which consists in separating base stations' Base-Band Units (BBU) from their Remote Radio Heads (RRH), and grouping them into consolidated “Hotels”, with reduced costs and energy consumption. In this work, we propose and model by an ILP formulation the novel “BBU Placement” network optimization problem, on a converged Multi-Stage WDM-PON. The aim is to decide in which nodes to place BBUs, together with the routing and wavelength assignment of traffic demands, such that the number of Hotels is minimized. We capture the importance of the maximum latency of Digitized Radio-over-Fiber (D-RoF) flows exchanged between each BBU and its RRH, which becomes a constraint on the maximum propagation delay of corresponding routes. Simulation results are obtained by generating some random multi-stage tree instances and solving them via CPLEX. The analysis of the number of Hotels versus network sizes and maximum D-RoF delay validates the proposed model and highlights the strong impact of such parameters on the achievable BBU consolidation.

[1]  Biswanath Mukherjee,et al.  Long-reach optical access networks: A survey of research challenges, demonstrations, and bandwidth assignment mechanisms , 2010, IEEE Communications Surveys & Tutorials.

[2]  Tibor Cinkler,et al.  Geography- and infrastructure-aware topology design methodology for broadband access networks (FTTx) , 2010, Photonic Network Communications.

[3]  Peter Vetter Next generation optical access technologies , 2012, 2012 38th European Conference and Exhibition on Optical Communications.

[4]  Ahmed Saadani,et al.  Base stations evolution: Toward 4G technology , 2012, 2012 19th International Conference on Telecommunications (ICT).

[5]  Brigitte Jaumard,et al.  Location and Allocation of Switching Equipment (Splitters/AWGs) in a WDM PON Network , 2011, 2011 Proceedings of 20th International Conference on Computer Communications and Networks (ICCCN).

[6]  Qing Wang,et al.  Wireless network cloud: Architecture and system requirements , 2010, IBM J. Res. Dev..

[7]  Glen Kramer,et al.  Wavelength-division-multiplexed passive optical network (WDM-PON) technologies for broadband access: a review (Invited) , 2005 .

[8]  G. Maier,et al.  Design and cost performance of the multistage WDM-PON access networks , 2000, Journal of Lightwave Technology.

[9]  Yoji Kishi,et al.  Colony-RAN architecture for future cellular network , 2012, 2012 Future Network & Mobile Summit (FutureNetw).