The ubiquitous need for bandwidth in our Internet-centric world has driven landline networks, as well as more recently deployed wireless networks, to network convergence. In the future, all networks are moving toward delivering high speed digital data from a data or processing source, through a high bandwidth or “broadband” network, to a wireless distribution point and reverse for the upstream.
Now and in the Future
The next wireless network architecture evolution is 4G/LTE densification and 5G wireless. This evolution is a convergence of the physical assets of fixed networks and wireless access points. For example, in North America, LTE coverage is relatively ubiquitous. Wireless “coverage” is complete for all intents and purposes. The issue, as consumer demand for data increases, is capacity. Wireless capacity can be increased in several ways: better modulation techniques, more spectrum or spatially. 4G/LTE densification and potentially 5G mobility create more capacity spatially. More small cells closer to each other (250 meters) means that there are less users at each access point, which effectively creates more bandwidth per square meter. The promise of fixed wireless 5G in the sub 6 GHz range and millimeter wave band (i.e. 28GHz) creates more bandwidth with additional spectrum as well.
When we think of convergence, we generally are considering these three types of networks and their typical configurations:
In the multi-service organization or legacy community access television network, there is a headend connected via router to data centers. The network consists of a high bandwidth hybrid fiber coax network. At the consumer/enterprise end of the network, the obvious trend is toward Wi-Fi wireless connectivity in the home or in the office.
- In legacy telephony networks, central offices or mobile switching centers are connected via high speed routers to data centers and other switching centers. The legacy telephony network consists of a legacy copper network, a version of FTTN (fiber to the node) supporting some form of advanced DSL service or an fiber to the home network. As in the HFC example, home and business routers and Wi-Fi are typically activated.
A traditional cellular network is comprised of a network of macro cells, each independently powered and interconnected by a backhaul network of varying types, inclusive of fiber, HFC, copper and microwave.
These three different networks all look different when deployed due to the need to meet different communications applications. Now they are all beginning to resemble each other to the point the networks can and will merge into one, saving operator OPEX and CAPEX as equipment requirements also become identical. This is network convergence. It not only drives the networks toward looking the same, but CAPEX will be reduced as manufactures and NFV/SDN (network function virtualization/software defined networks) become standard.
In a converged network, three things are required, one of which we’ll talk about here:
The requirement for power at every wireless access point is essential, but often assumed as available or even forgotten until the completion of network planning. Each legacy telecommunications network has different powering considerations. But make no mistake: the requirement for power in a converged network is real, and the importance cannot be overstated.
Legacy telephone networks, where twisted pair still exists and maintained, can provide low levels of power for small cells. In general, for a converged network, legacy telephony networks require utility power to be acquired unless a wireless access point is collocated at a power cabinet.
FTTH PON networks simply do not have this access to power, apart from the installation of a utility drop and meter installation. While a utility drop can be acquired at reasonable cost, and perhaps in a reasonable timeframe, the installation of a utility drop at hundreds or thousands of access point locations will quickly become both an economic burden as well as a project bottleneck.
Estimates are that 80 percent of HFC plant miles have network power availability due to the power on the coax. Coax in many cases runs parallel as a back-feed from an optical node thereby creating power availability even in fiber portions of the plant. In most cases the power availability is more than adequate for Wi-Fi hotspots or small cells.
Two more attributes are needed for successful convergence: backhaul and site acquisition. We’ll explore those in Part 2.