Is the road to FTTH paved by 5G?

By Rajesh Abbi

April 2, 2017

Now – you must be wondering – what in the world has 5G got to do with Fiber-to-the- Home (FTTH)?

Wireline operators have been pushing fiber in the last mile getting closer to the home and businesses as we discussed in our last quarterly. Unfortunately, their ultimate dream of fiber-to-the-home keeps running up against the rude reality of high cost/complexity of digging up streets and neighborhoods.

Wireless operators, on the other hand, didn’t have much to worry on that front – well, at least that’s what they thought.

As the limited amount of available cellular spectrum gets exhausted, and bandwidth requirements continue to grow, the next generation of mobile networks (5G) are being forced to tap into previously unused spectrum at much higher frequency. One such band of spectrum targeted for use with 5G is termed Millimeter Wave Band (mmWave) as the wavelength of the waves in this band fall in the millimeter range. The mmWave band offers tremendous amount of potential spectrum capacity (Figure 1). Why then, one would ask, has this vast spectrum not been used till now?

Figure 1 – The Millimeter Wave band for 5G offers tremendous capacity

The answer lies in the propagation characteristics of mm Waves. Waves at this frequency suffer high absorption from water molecules in the atmosphere and cannot travel very far. Also, they get blocked easily by all kinds of obstacles – trees, buildings, even human body (Figure 2). This means they are only effective for short range communication requiring line of sight.

Figure 2 – Millimeter Waves suffer high absorption by water molecules in the air and get blocked easily

In order to make use of the mmWave spectrum, the cell size has to be relatively small – requiring the base stations to be placed much closer to the subscribers. Cellular base stations need fiber to backhaul the large amount of data. This means Wireless operators also now have a need to drive fiber deeper and closer to the subscribers.

It appears the stars are aligning well to drive fiber-to-the-node (FTTN) deployment on all fronts. It’s only the last few hundred feet that are still up for grabs – will it be twisted-pair copper with G.fast, coax cable with DOCSIS 3.1/FDX, or wireless with mmWave (Figure 3).  No wonder then, it is only fair to say that 5G is helping pave the road to eventual FTTH.

Figure 3 – Next Generation Access Networks are evolving to Fiber-to-the-Node (FTTN)

So, what does this mean for you? If you are a Wireline operator – you can offer fiber build services to Mobile operators. Mobile operators on the other hand will have to either build their own FTTN infrastructure, or more likely, partner with incumbent wireline operators for the fiber infrastructure.