100Gbps DMT ASIC for Hybrid LTE-5G Mobile Fronthaul Networks

Abstract

Multiple access interfaces are required to provide the wireless coverage and capacity that operators need for consistent service across their geographic footprint. As a consequence, future radio access networks will be hybrid 4G/LTE-5G networks. This technology evolution is creating many challenges in the mobile fronthaul (MFH) networks to support the co-existence of common public radio interfaces (CPRI) and evolved common public radio interfaces (eCPRI) traffic with diverse connectivity requirements in term of capacity and reach. To address these challenges, this paper introduces a 100 Gb/s discrete multi-tone modulation (DMT) ASIC which has been designed and fabricated in 16 nm CMOS process, specifically targeting MFH applications. This DMT ASIC can flexibly support various important data rates in hybrid 4G/LTE-5G MFH networks, including CPRI-10, 25 GbE, 50 GbE, 75 GbE, and 100 GbE (eCPRI rates) over the full industrial temperature range (−40 °C to +85 °C). We demonstrate the high performance and reliability of this DMT ASIC in several real time transmission experiments, including: i) 200 Gb/s LAN-WDM2 transmission over 20 km in O-band using two 25-GHz class directly modulated lasers (DMLs); and ii) 200 Gb/s, 300 Gb/s and 400 Gb/s WDM transmissions over up to 40 km in C-band using 4 wavelengths, each with data rate of 50 Gb/s, 75 Gb/s, and 100 Gb/s, respectively. The success of these experiments clearly indicates the attractiveness of the presented DMT ASIC for future MFH applications. In addition, in several transmission scenarios, the advantages of DMT format over conventional PAM4 format for MFH applications are highlighted.