Multi-cell coordination for 60 GHz RoF fronthaul enabled by a non-orthogonal multiple access scheme without successive interference cancellation.

We propose and experimentally demonstrate a non-orthogonal multiple access (NOMA) enabled 60 GHz radio-over-fiber (RoF) fronthaul system with coordinated base stations, improving the data rate and coverage of 60 GHz RoF systems. First, coordinated multipoint transmission using space-time block coding (STBC) is adopted in fronthaul, achieving 1.3 dB improvement in receiver sensitivity compared to two fronthaul links' transmission without STBC. Second, multi-cell coordination in RoF fronthaul is presented, where a multi-level code (MLC)-based NOMA scheme is employed. A sum rate of 6 Gbps for three users is achieved along 10 km fronthaul transmission and 1.24 m wireless transmission. The experimental results show that the valid power allocation ratio range improves from 3.5≤R≤4.2 in conventional superposition code-based NOMA fronthaul to 3≤R≤5 in our proposed coordinated MLC-NOMA fronthaul link.

Characterization of highly-sensitive and fast-responding monitoring module for extended-reach passive optical networks.

The extended-reach broadband access network is widely acknowledged as a future-proof solution to providing bandwidth-intensive services to an increased number of users spread across a large geographical area. To address fiber failure detection and reliability issues specific to these networks, a simple automatic protection switching and pump laser shutdown scheme that exploits the use of highly-sensitive and fast-responding monitoring modules is proposed and experimentally demonstrated in this work. We also present an analytical model that describes the probability distribution function of the response time, thus allowing the mean response time, jitter, and sensitivity to be evaluated. Our results show a high sensitivity of < -50 dBm can be achieved, thus allowing the module to be applied in topologies with extended reach and/or split ratio beyond that of conventional PONs.

Technique to improve carrier-to-interference ratio of optical single sideband with carrier modulated signals.

We propose and demonstrate a simple technique to improve the carrier-to-interference ratio (CIR) of optical single sideband with carrier modulated signals for fiber-radio applications. The proposed scheme is demonstrated via experiment and simulation with a two-tone test showing that an improvement in CIR of 9 dB can be achieved.