There are many available technologies that will extend the life of hybrid fiber coaxial (HFC) networks.
These include Full Duplex DOCSIS (FDX), Soft Full Duplex DOCSIS (Soft-FDX), and Extended Spectrum DOCSIS (ESD). This paper will provide an overview of these technologies along with capacity simulation results and a gradual migration strategy. It will be shown that HFC networks have enough capacity to meet the demand and address competition for the next two decades.
HFC networks are in the best position to create the future 10G networks, which are needed to support symmetrical services through the Data Over Cable Service Interface Specifications (DOCSIS). Multiple technologies are available to augment the current capacities of HFC networks, such as FDX and ESD.
Some of the early deployments of the FDX & ESD technologies can be focused on increasing the upstream (US) throughput. This can be done by utilizing a special mode of FDX, where the FDX node and modem technology are used to move the US split to a higher frequency. This deployment scenario is called Soft-FDX and is suitable for cascaded N+x (i.e., Node followed by x amplifiers) networks.
This paper shows how these technologies are complementary in nature and explains how the Soft-FDX technology can deliver similar performance to that of the traditional FDX while using the same node technology and modem silicon chips that are currently being developed for first generation of FDX products. The paper also explains the inefficiencies in spectrum usage that results from configuring FDX grids with small allocated FDX spectrum sizes. Furthermore, it proposes operational modes and spectral configurations that will allow FDX modems that are running in FDX mode to efficiently utilize the spectrum regardless of the size of the allocated FDX spectrum.
The paper additionally shows some simulation results of potential capacities that can be achieved in cascaded N+x Soft-FDX networks when using first generation FDX node and modem silicon. It also compares this capacity to the capacity that can be obtained from running the network in a native N+0 traditional FDX operation. ESD simulations to 1.8 GHz and 3 GHz are also provided.
Another operational complexity that is studied in this paper is the topic of video delivery and out-of-band (OOB) signal handling in both N+0 traditional FDX and N+x Soft-FDX networks.
The paper also discusses various network migration strategies that will help the multiple service operators (MSOs) in selecting gradual evolution steps to reach the desired goal architecture.
The paper is organized as follows. Section 1 provides high-level FDX overview. FDX grids and potential inefficiencies are discussed in Section 2. Section 3 discusses FDX for cascaded networks, which is followed by the Soft-FDX overview in Section 4. Section 5 provides simulations results for FDX & Soft FDX systems. FDX Taxonomy is proposed and discussed in Section 6. Section 7 discusses video OOB delivery mechanism. ESD is discussed and simulations results are provided in Section 8. Finally, Section 9 proposes a network migration diagram and discusses various network migration strategies.