Analogue Radio Over Fiber Aided MIMO Design for the Learning Assisted Adaptive C-RAN Downlink

Abstract

The cloud/centralized radio access network (C-RAN) architecture is recognized as a strong candidate for the next generation wireless standards, potentially reducing the total cost of ownership. Spatial modulation (SM) is a cost-effective multiple-input-multiple-output (MIMO) solution, where only a single-radio frequency chain is required for transmission. In this context, we propose analogue radio over fiber (A-RoF) aided MIMO techniques for learning assisted adaptive C-RAN system, where SM combined with space-time block coding is optically processed relying on the optical frequency indices in the central unit of the C-RAN, which also is capable of tuning the connected remote radio heads (RRHs). Furthermore, to improve the spectral efficiency, we invoke our proposed flexible C-RAN architecture for implementing learning assisted transceiver adaptation, where the number of RRHs connected to a single user and its modulation techniques employed are controlled using the K-nearest neighbor algorithm. The simulation results show that the bit error ratio performance of our A-RoF system is only marginally degraded compared to that operating without the A-RoF link, while benefiting from our energy-and cost-efficient C-RAN design. Moreover, we show that the learning assisted adaptation is capable of outperforming the classic threshold-based adaptation in terms of the system's achievable rate.

Analog Radio Over Fiber-Aided Multi-Service Communications for High-Speed Trains

“…The QoS degradation of A-RoF compared to the digital solution is not presented in this paper since we focused on the beamforming design using the proposed A-RoF system. However, this issue has been widely investigated and demonstrated in our recent papers[16],[19],[35] as well as other literatures[36],[37], where it is shown that A-RoF based system is capable of supporting 5G signals with an acceptable degradation of QoS. For example in[16], we experimentally verified that the A-RoF system is capable of supporting a 2 × 2 MIMO system with less than 1 dB SNR degradation compared to the traditional system…”

Design and Prototype Implementation of Software-Defined Radio Over Fiber

“…To manage the rapidly increasing data rates, implementation costs will become a major challenge with D-RoF [14]. From this perspective, particularly, A-RoF-based C-RAN has attracted much attention in recent years [15], [16]. The analog-millimeter-wave-over-fiber fronthaul architecture [17] and the machine learning-based A-RoF C-RAN architecture [18] have also been discussed towards 6G communications.…”

“…From this perspective, particularly, A-RoF-based C-RAN has attracted much attention in recent years [15], [16]. The analog-millimeter-wave-over-fiber fronthaul architecture [17] and the machine learning-based A-RoF C-RAN architecture [18] have also been discussed towards 6G communications. In these methods, the C-RAN is constructed by aggregating mobile signals using WDM.…”

Practically Feasible Closed-Loop Digital Predistortion for VCSEL-MMF-Based Radio-over-Fiber links

“…RoF is a suitable technology to cope with the on growing demand of high bandwidth multivariate wireless services both for outdoor and indoor scenarios [5][6][7], and is looked upon as an enabling technology for next generation networks [8], [9]. Moreover, thanks to the low attenuation of the optical fiber, the radio signals can be transmitted with a reduced need of repeaters or amplifiers.…”