Delta-Sigma Digitization and Optical Coherent Transmission of DOCSIS 3.1 Signals in Hybrid Fiber Coax Networks

Abstract

We first demonstrate delta-sigma digitization and coherent transmission of data over cable system interface specification (DOCSIS) 3.1 signals in a hybrid fiber coax (HFC) network. Twenty 192-MHz DOCSIS 3.1 channels with modulation up to 16384QAM are digitized by a low-pass cascade resonator feedback (CRFB) delta-sigma analog-to-digital converter (ADC) and transmitted over 80 km fiber using coherent single-λ 128-Gb/s dual-polarization (DP)-QPSK and 256-Gb/s DP-16QAM optical links. Both one-bit and two-bit delta-sigma digitization are implemented and supported by the QPSK and 16QAM coherent transmission systems, respectively. To facilitate its practical application in access networks, the coherent system is built using a low-cost narrowband optical modulator and RF amplifiers. Modulation error ratio (MER) larger than 50 dB is successfully demonstrated for all 20 DOCSIS 3.1 channels, and high order modulation up to 16384QAM is delivered over fiber for the first time in HFC networks. The raw DOCSIS data capacity is 54 Gb/s with net user information ~45 Gb/s. Moreover, the bit error ratio (BER) tolerance is evaluated by measuring the MER performance as BER increases. Negligible MER degradation is observed for BER up to 1.5 × 10 −6 and 1.7 × 10 −4 , for one-bit and two-bit digitization, respectively.

DRoF-Based Optical Video Re-Transmission System with Adaptive Combination Compression for Rain Attenuated Satellite Broadcast Signals

“…Similar to CPRI, in hybrid fiber-coaxial (HFC), DRoF is applied in baseband digital forward or return (BDF/BDR). BDF/BDR is defined as an interface for connecting fiber nodes of the HFC network and cable modems [14], [15]. BDF/BDR provides a simple, service-transparent digitized interface.…”

“…BDF/BDR provides a simple, service-transparent digitized interface. The BDF/BDR digitization process uses the fixed quantization number of 12-bits [14], [15]. As mentioned above, some commercial systems basically perform very simple uniform fixed quantization.…”

“…T r = (NF − 1)T 0 (14) The input CNR to DRoF-Tx is calculated using Eqs. ( 7) to (14). Here, the parameters used in the CNR calculation are given in Table 2.…”

Towards Enhanced Mobile Broadband Communications: A Tutorial on Enabling Technologies, Design Considerations, and Prospects of 5G and beyond Fixed Wireless Access Networks

“…Furthermore, DOCSIS of the MCNS is the de facto standard in the cable industry [107]. For instance, in the United States, a very huge number of broadband subscribers that are about 40% more than fiber and DSL subscribers are being served by the cable companies [109,110]. The trend can be mainly attributed to a notable relentless evolution in cable technology as presented in Table 1.…”

“…In addition, higher-order modulations up to 4096 QAM have been adopted with optional support for 8192 and 16384 QAM. Furthermore, like Long-Term Evolution (LTE) networks in which carrier aggregation (CA) is supported, recent DOCSIS specifications support channel bonding [110]. The enhancements enable support for mobile backhaul/fronthaul (MBH/MFH), ultra-high resolution videos (4K/8K), and other virtual reality and IoT-enabled emerging applications.…”