Will the NBN be obsolete before it’s finished?

With the constant march of technology, there are often concerns expressed that the NBN may be obsolete before it’s even finished.

So what are the chances of this happening, and what technologies could potentially make the NBN obsolete?

Let’s begin with a basic explanation of the fibre portion of the NBN. It uses fibre-optic cable to transmit data in the form of light pulses. Fibre optic cables have been in service for about 40 years, and are the technology used to carry all the phone and internet traffic across and between countries. Our telephone exchanges are already linked by fibre cable, as are our wireless towers. Currently, there are only 6 major fibre optic cables joining Australia to the rest of the World, comprising a total of just 24 strands of fibre which carry basically all the telephone, FAX and internet traffic in and out of our country. What the NBN is doing is taking that fibre cable all the way to each house.

The strands of glass fibre used in NBN cables is technically the same as the fibre used in the cables joining countries together. While it won’t be used to carry the same massive data quantities, it is quite capable of carrying that much data in the future if required. The capacity of fibre cables is almost unlimited, and speeds are constantly increasing through the use of technologies such as Wavelength-division multiplexing.

The main system being used for the home NBN connections is called a GPON (or Gigabit Passive Optical Network). This allows for speeds of up to 1 Gigabit per second (Gbps) and is currently the fastest such technology available. If faster versions of GPON are developed in the future, the NBN can be upgraded in a similar way as the copper network was upgraded from ADSL to ADSL2+. In other words, the cables remain the same, but the equipment is upgraded to take advantage of the faster speeds.

However, bear in mind that 1Gbps is the fastest internet system being implemented anywhere in the World, and is 100 times faster than the current average broadband speed in Australia. Even if faster GPON systems become available, the NBN will certainly not become obsolete.

Contrary to erroneous claims, fibre optic cables have no specific lifetime or known failure mechanism. There have been no widespread failures of exisCorning, one of the World’s largest manufacturers (and the supplier of NBN fibre cables), report that they have fibre cables submerged and under tension, and still working flawlessly after 35 years of constant testing. They also report that cable construction has improved over that period, so cables manufactured today are even more durable. Other manufacturers predict an average life of 60 years.

Could copper provide faster speeds than the NBN?

No. There is no copper technology in use or under development that can provide the speeds available over fibre. This is why telecommunication companies replaced their copper inter-exchange links with fibre decades ago. Fast copper technologies (such as VDSL2) are able to provide good speeds over very short distances, but they require two phone lines in excellent condition to do so. There is no prospect that any copper technology could overtake fibre for speed, primarily due to physical limitations of copper wire, including resistance, attenuation and signal-noise ratio.

The other copper-based technology is Hybrid Fibre Coaxial (HFC) cable. This is the pay TV cable used in some areas of Australia. It uses fibre for the main ‘trunk’ connections, and copper co-axial cable for the ‘branches’ down side streets. In some areas, it is capable of delivering 100Mbps to be shared amongst users on each branch. There is no prospect of HFC ever delivering speeds that exceed the NBN’s 1Gbps.

Could wireless broadband provide faster speeds than the NBN?

No. Unfortunately, the speed and capacity of wireless networks is hampered by unassailable limitations of the technology. It is a physical impossibility for any wireless network to be capable of exceeding the speed or capacity of a fibre-optic network.

Each time we increase the speed of a wireless network or add more users, it consumes more of the radio spectrum. There is only a very small amount of radio spectrum available for use in wireless broadband networks, because other frequencies are reserved for use in broadcasting, CB radios, WiFi networks and assorted other communication systems. The available spectrum for wireless broadband must then be shared amongst all the network operators. For example, if there is 300MHz available, Telstra may own 100MHz, Optus another 100MHz and Vodafone the final 100MHz. Delivering high speeds then becomes even more difficult, because it is rare for any one operator to own continuous blocks of frequencies, which is what’s required to deliver higher speeds.

However, even if you could eliminate all other radio uses and allocate everything to one wireless operator, a single strand of fibre optic cable can still carry thousands of times more information that the entire radio spectrum put together.

Another fact to keep in mind is that when you hear the speeds of wireless networks being reported, the quoted speeds represent the theoretical capacity of each cell of the network. These speeds are never achievable in practice, both due to technical limiting factors (such path loss from obstructions, distance and weather), and by the number of users connected to the cell at any one time. Typically, users achieve maximum speeds of about 1/10th of the quoted network speed, but often far less than that. The more users on the wireless network, the slower it operates.

As previously discussed, there is not a single country or telecommunications company anywhere in the World that is proposing a wireless network to replace their fixed network in urban areas, including the United States.

There is much more information on wireless in the following articles:

• Broadband Facts, Fiction and Urban Myths

• NBN: Why Not Wireless?

There is no technology currently available, in development, or even on the drawing boards that can make fibre-optic cables obsolete.


One Response to Will the NBN be obsolete before it’s finished?

  1. Frank Goudis says:

    Thankyou for this explanation. I had no idea fibreoptic had so much potential for faster speeds.

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