SDN based millimetre wave radio over fiber (RoF) network

Abstract

This paper introduces software-defined, millimeter Wave (mm-Wave) networks with Radio over Fiber (RoF) for the delivery of gigabit connectivity required to develop fifth generation (5G) mobile. This network will enable an effective open access system allowing providers to manage and lease the infrastructure to service providers through unbundling new business models. Exploiting the inherited benefits of RoF, complete base station functionalities are centralized at the edges of the metro and aggregation network, leaving remote radio heads (RRHs) with only tunable filtering and amplification. A Software Defined Network (SDN) Central Controller (SCC) is responsible for managing the resource across several mm-Wave Radio Access Networks (RANs) providing a global view of the several network segments. This ensures flexible resource allocation for reduced overall latency and increased throughput. The SDN based mm-Wave RAN also allows for inter edge node communication. Therefore, certain packets can be routed between different RANs supported by the same edge node, reducing latency. System level simulations of the complete network have shown significant improvement of the overall throughput and SINR for wireless users by providing effective resource allocation and coordination among interfering cells. A new Coordinated Multipoint (CoMP) algorithm exploiting the benefits of the SCC global network view for reduced delay in control message exchange is presented, accounting for a minimum packet delay and limited Channel State Information (CSI) in a Long Term Evolution-Advanced (LTE-A), Cloud RAN (CRAN) configuration. The algorithm does not require detailed CSI feedback from UEs but it rather considers UE location (determined by the eNB) as the required parameter. UE throughput in the target sector is represented using a Cumulative Distributive Function (CDF). The drawn characteristics suggest that there is a significant 60% improvement in UE cell edge throughput following the application, in the coordinating cells, of the new CoMP algorithm. Results also show a further improvement of 36% in cell edge UE throughput when eNBs are centralized in a CRAN backhaul architecture. The SINR distribution of UEs in the cooperating cells has also been evaluated using a box plot. As expected, UEs with CoMP perform better demonstrating an increase of over 2 dB at the median between the transmission scenario

Reconfigurable Radio-Over-Fiber Networks [Invited]

“…Active networks, in combination with RoF technologies, are hence an interesting way of enabling a higher degree of reconfigurability in scenarios in which the end user is mobile per se, and requires low-latency, high-throughput, and physical layer security features. There have been several demonstrations of optical switching of RoF signals, employing, for example, passive optical cross-connect switches [24] and active switches using semiconductor optical amplifiers [25]. The main challenge in these approaches is that either the power budget is reduced drastically due to the insertion losses of the switch, or the distortions induced by active components degrade the signals in spite of a large port count and high level of dynamism.…”

“…Most RoF systems focus largely on passive distribution approaches; however, it is becoming obvious that a passive system's efficiency is low in terms of bandwidth utilization, and power budget issues limit the splitting ratio and the attainable link lengths [24]. Furthermore, the intrinsic nature of the distribution approach (point-to-multipoint multicast) may raise concerns in terms of security, particularly in industrial or business environments.…”

“…On top of the inherent advantages of dealing with baseband signals in the optical domain, the C-RAU is compatible with current trends in networking as software-defined networking (SDN). This enables reconfigurability at both the physical and the management layers [24].…”