Radio-over-modes for C-RAN architecture with smart optical resources assignment

Abstract

In this paper we consider a centralized radio access network (C-RAN) architecture with a fully analog fronthaul link between remote radio heads (RRHs) and baseband units (BBUs) based on the radio over fiber (RoF) paradigm. Mode division multiplexing (MDM) and frequency division multiplexing (FDM) are employed to provide an additional multiplexing signal dimension to meet the huge bandwidth requirements of next generation (5G) wireless mobile systems. The main contribution of the paper is to prove that a smart resource assignment between the radio antennas and the mode/frequency dimensions allows the communication over the RRH-BBU link at rates that are comparable to those achieved by an ideal fronthauling where BBU and RRH are assumed to be co-located, even without any complex and costly optical equalization technique. Validation is on the radio-link capabilities employing multiple antennas to meet the demand for massive MIMO technology.

Frequency division multiplexing for very high capacity transmission in bandwidth-limited systems

“…Although FDM mobile signals assisted by analog and digital signal processing have been already exploited [7], an effective combination of FDM and MDM offers a further degree of freedom in the design of wireless antennas assignment performed by beamforming, able to overcome the limitations of intermodal crosstalk. We demonstrate [8] that after 10-km propagation in a few mode fiber, when employing commercial mode MUX/DEMUX, the joint exploitation of FDM and MDM (where the same number of antenna elements can be supported by different combinations of FDM subcarriers and modes) improves the MFH performance (as shown in Fig. 3 b) allowing to achieve capacities near the ideal ones.…”

A Joint Scheduling and Beamforming Scheme for RoF-Aided MC-SSN

“…MIMO and mmWave technologies are capable for such system, achieving high capacity gain and limited resource assumption [8], [11], [16]. Moreover, some adaptive and intelligent frameworks are introduced, such as cloud/edge [10], [17], [18] or fog/edge computing, software defined network (SDN), multihop/multilayer network [19]- [22], integrated wireless sensor network (WSN) and hybrid LiFi/WiFi [23], etc.…”

“…Dowhuszko et al [29] have been working on randomly beamforming as well as the opportunistic scheduling for machine-to-machine (M2M) scenario. References [10] and [18] focused on the resource allocation optimization for multimedia heterogeneous cloud radio access networks (H-CRANs) and achieved a higher energy efficiency (EE). Reference [10] proposed a joint mode division multiplexing (MDM) and frequency division multiplexing (FDM) based fronthauling scheme allowing cost-effective and bandwidth efficient connections in RoF system.…”

“…References [10] and [18] focused on the resource allocation optimization for multimedia heterogeneous cloud radio access networks (H-CRANs) and achieved a higher energy efficiency (EE). Reference [10] proposed a joint mode division multiplexing (MDM) and frequency division multiplexing (FDM) based fronthauling scheme allowing cost-effective and bandwidth efficient connections in RoF system. But the work was designed for the single layer centralized radio access network (C-RAN) and implemented for one served user and limited antenna elements.…”

“…It is a system with the following advantages [8]: Low attenuation, simplicity and cost-effectiveness, low cost expandability, high capacity, flexibility and dynamic resource allocation. RoF system is also capable for supporting MIMO transmission with the deployment of multi-mode fiber [10], [11].…”