RESUMO
The telecommunication society is paving the way toward ultra-high frequency regions, including the millimeter wave (mmWave) and sub-terahertz (sub-THz) bands. Such high-frequency electromagnetic waves induce a variety of physical constraints when they are used in wireless communications. Inevitably, the fiber-optic network is deeply embedded in the mobile network to resolve such challenges. In particular, the radio-over-fiber (RoF)-based distributed antenna system (DAS) can enhance the accessibility of next-generation mobile networks. The inherent benefits of RoF technology enhance the DAS network in terms of practicality and transmission performance by enabling it to support the 5G mmWave and 6G THz services simultaneously in a single optical transport link. Furthermore, the RoF allows the indoor network to be built based on the cascade architecture; thus, a service zone can be easily added on request. This study presents an RoF-based multi-service DAS network and experimentally investigates the feasibility of the proposed system.
RESUMO
We demonstrate the analog indoor distributed antenna system (DAS) for 5G mobile communications that supports 4 × 4 multiple-input multiple-output (MIMO) configuration. For this, we exploit a pair of intermediate frequency over fiber (IFoF)-based analog optical links, transporting 32 frequency allocation (FA) 5G mobile signals (effectively ~4 GHz bandwidth). The analog optical link manifests its high fidelity in the measured characteristics: small gain variation (< ± 1 dB for the entire transmission bandwidth), low noise (<-136 dBm/Hz), and large dynamic range (spurious free dynamic range of >106 dBâHz2/3), subsequently providing superior error vector magnitude (EVM) performance (~2%) for a wide range of ambient temperatures (-20 ~60°C). Consequently, the IFoF-based 4 × 4 MIMO supporting analog indoor DAS is capable of providing record high peak throughput of 5.3 Gb/s for millimeter wave based 5G mobile communication system.
