Distributed Antenna System Using Sigma-Delta Intermediate-Frequency-Over-Fiber for Frequency Bands Above 24 GHz

Abstract

The fifth generation (5G) cellular network is expected to include the millimeter wave spectrum, to increase base station density, and to employ higher-order multiple-antenna technologies. The centralized radio access network architectures combined with radio-over-fiber (RoF) links can be the key enabler to improve fronthaul networks. The sigma-delta modulated signal over fiber (SDoF) architecture has been proposed as a solution leveraging the benefits of both digitized and analog RoF. This work proposes a novel distributed antenna system using sigma-delta modulated intermediate-frequency signal over fiber (SDIFoF) links. The system has an adequately good optical bitrate efficiency and high flexibility to switch between different carrier frequencies. The SDIFoF link transmits a signal centered at a 2.5 GHz intermediate frequency over a 100 m multi-mode fiber and the signal is up-converted to the radio frequency (24-29 GHz) at the remote radio unit. An average error vector magnitude (EVM) of 6.40 % (-23.88 dB) is achieved over different carrier frequencies when transmitting a 300 MHz-bandwidth 64-QAM OFDM signal. The system performance is demonstrated by a 2×1 multiple-input single-output system transmitting 160 MHzbandwidth 64-QAM OFDM signals centered at 25 GHz. Owing to transmit diversity, an average gain of 1.12 dB in EVM is observed. This work also evaluates the performance degradation caused by asynchronous phase noise between remote radio units. The performance shows that the proposed approach is a competitive solution for the 5G downlink fronthaul network for frequency bands above 24 GHz.

Automatic Distributed MIMO Testbed for Beyond 5G Communication Experiments

“…To experimentally evaluate the performance of new B5G wireless systems such as cell-free/distributed MIMO in complex environments, large number of measurements are needed. However, all reported testbeds have relied on manual measurements or have a small number of transmitters and receivers [6][7] [8][9] [10]. Naturally, these measurements become very time consuming and do not generate sufficient data for statistical purposes.…”

SiPhotonics/GaAs 28-GHz Transceiver With Reflective EAM for Laser-Less mmWave-Over-Fiber

“…The remote radio units (RRUs) should, on the other hand, be mass-deployable and, therefore, be as cost-effective as possible. Next-generation radio access networks (NG-RAN) [3], [4] consist of central units (CUs) which are connected to the core network via the backhaul (Fig. 1).…”

60 GHz Resonant Photoreceiver With an Integrated SiGe HBT Amplifier for Low Cost Analog Radio-Over-Fiber Links

“…A big issue with moving to mmWave frequencies is the higher path loss therefore multiple distributed antenna units are needed to provide coverage to an area and it is preferable to consolidate baseband units (BBU) and share capacity across remote radio heads (RRH) [6], [7]. Typically, digital optical fiber links carrying common public radio interface (CPRI) data have been used to connect BBUs to RRHs as shown in Fig.…”

“…Intermediate frequency-over-fiber (IFoF) has been promoted as a lower cost solution compared to DRoF but it requires upconversion at the RRH [8]. Sigma-delta radioover-fiber (SDMRoF) proposes a simple RRH architecture but has only been demonstrated up to 28 GHz [6]. Analog radio-over-fiber (ARoF) using optical single sideband (OSSB) modulation has been demonstrated as a preferred solution for large scale mmWave deployments due to elimination of dispersion induced power fading while offering a simple RRH architecture [9].…”