By Stowe Boyd, Managing Director, Gigaom Research
It’s impossible to understand the future of mobile — and the impact that new technologies and new patterns of communication will have on business and society in the coming years — without a basic understanding of how today’s 4G cellular networks and modern Wi-Fi work.
If you already have a solid understanding of technical terms like MIMO-OFDM, 802.11ac, and WiMax, you can jump ahead to the What Will 5G Be Like? section, below. If you don’t, you might want to wade through the next nine paragraphs to get a grounding.
How do cellphones communicate?
Most modern cellphones use several sorts of communications technologies. Cellphones can transmit and receive by the cellular connection to the phone network (rooftop range), by Wi-Fi (medium range), by Bluetooth (short range), and by near-field communication, or NFC, (extremely short range).
These different sorts of communication systems are also using different radio frequencies and are used in very different ways. 4G — for fourth generation — cellular networks, in addition to the standard voice, text, and other services of earlier cell networks, provides data connection, which means that mobile Internet access is supported.
In the U.S., Sprint provides a mobile WiMax approach to 4G, and Verizon, AT&T, T-Mobile, and Sprint use 4G-LTE, or 4G Long-Term Evolution. Neither of these approaches meet the full international spec for “true 4G.” Sprint is phasing out WiMax, so let’s focus just on LTE.
4G LTE is based on modern digital signal modulation technologies that became available at the turn of the millennium. LTE supports scalable carrier bandwidths, from 1.4 MHz to 20 MHz, and uses a variety of techniques to increase the scale of communication for the available bandwidth. This means that 200 active data clients can be supported on a standardized cell running at 5 MHz, with peak download rates up to 299.6 Mbits/s and upload rates up to 75.4 Mbits.
At the core of 4G is a protocol called MIMO-OFDM (Multiple Input, Multiple Output-Orthogonal Frequency Division Multiplexing). As defined by Wikipedia, “It combines multiple input, multiple output (MIMO) technology, which multiplies capacity by transmitting different signals over multiple antennas, and orthogonal frequency-division multiplexing (OFDM), which divides a radio channel into a large number of closely spaced sub channels to provide more reliable communications at high speeds.”
Basically, it works by treating a single signal as multiple signals in parallel, based on multiple communication paths from the sender and the receiver, like a cell network and your cellphone. Note that MIMO-OFDM is also used in the newest version of Wi-Fi is 802.11ac, which is much faster than the baseline 802.11.
Just as we take advantage of Wi-Fi and Bluetooth in parallel on our phones — downloading a movie via Wi-Fi and playing music to a speaker by Bluetooth at the same time — MIMO uses multiple frequencies, communication paths, and antennas to speed up communications.
MIMO is also the underpinning of the 802.11ac Wi-Fi implementation, which can exploit the two Wi-Fi frequencies — 2.4 and 5 GHz — to multiplex two or more communication paths. So I could, for example, be on a Voice over IP (VoIP) call on one Wi-Fi channel, while streaming a movie on the other.
Bluetooth and NFC are less critical to the discussion below about 5G, so I will leave them to one side, since they are secondary to the big impacts of the coming generation of mobile communications.
What will 5G be like?
We are headed for one of those mind-bending transitions, where a specific technological advance turns things inside out. An example from the early industrial era is the transition from the early use of large, stationary steam and then later electrical motors that drove tools like drills, saws, and lathes via leather belts. The invention of small electrical motors meant that the tools could operate independently and the complexities of drawing power from belts could be replaced with motors specialized for each sort of tool. Ultimately, that led to handheld power tools that we use today, the idea of running electrical wires in the walls.
5G is the term being applied to the technologies envisioned to be capable of dealing with the ever-expanding demand for higher speed mobile communications. There are several parts envisioned in this transition, which is not a standard, but just a collection of likely trends that will converge in the near term. The European Commission has made strides in this area, moving forward with an initiative — to be funded up to €700 million — for “ubiquitous 5G communication systems,” envisioning increasing wireless capacity by 1,000 times, and one that will be able to deal with the explosion of devices in the Internet of Things: 7 trillion devices and 7 billion people.
Today, 4G relies on rooftop base stations, which has led to a battle among the vendors for more rooftops to support LTE. But even with a lot more rooftops, the LTE cell networks need a lot more base stations. The answer is going to be ‘small cells’, which are smaller, street-level devices, embedded in kiosks, lampposts, bus stops, and even public toilets. To get the maximum boost, these will need to be connected to fiber, and as the data transmission speeds passing through that fiber rise, then those small cells will deliver gigabytes per second of capacity.
“This is a wildly inverted world, where the ultimate end point — the mobile phone — moves past being the most used communication tool and becomes the hub of all our communication.” – STOWE BOYD
The inventor of MIMO, Greg Raleigh, was asked about 5G, and he said “4G is very specific and was based on my invention of MIMO to exploit multipath [communications]. It’s not just multiple antennas at the transmitter and the receiver but it employs multidimensional signal processing to take advantage of multipath —that completely defines what 4G is. 5G is a mix and match — more MIMO, variations of MIMO than what was employed in 4G. It’s small cells, fiber backhaul, really a lot of incremental improvements on the radio infrastructure. Many of these things will make a big difference. Small cells are most likely the main source of speed improvement.”
So, envision the 5G future. Density and scalability of base stations will increase by at least 1,000 times, so when I emerge at Grand Central Terminal along with thousands of others in the not-too-distant future, I will be able to bring up Google Maps on my mobile phone in milliseconds, instead of waiting until I’ve walked five blocks away before even trying.
Perhaps the greatest shift 5G cellular with 802.11ac (and later) means that I will be able to use my cellphone as a replacement for today’s standard Internet connection — the cable modem and Wi-Fi router pair — at least in locations where small cells are providing high-speed 5G to the phone. In this future, mobility will mean the phone can be used to upload, download, run apps, etc., and at the same time provide Wi-Fi connectivity to other devices, like tablets, laptops, printers, TVs, and a growing array of IoT devices.
And that is that mind-bender. For many Internet service providers, the speeds available from the combination of 5G and 802.11ac (and beyond) will be enormously destabilizing. The chokehold that cable companies have in the U.S. will be undone, and users will be able to “cut the cord”: which in this instance doesn’t mean turning of cable TV, but turning off the cable to the house or office altogether. We might still be paying for TV, but “The Simpsons” would be coming through our phones and 5G, not cables in the street.
In such a scenario, we would be able to carry our only connectivity with us, built into the phone. This is analogous to people turning off their landline and only using mobile phones. This will up end one element of today’s cable monopoly, perhaps the last one left, by then.
This will be the true untethering. True wireless. Yes, the small cells will be connected to wires, but stores, schools, libraries, homes, and offices might be able to turn off the modems, pull down the Ethernet cable, and shut off the cable accounts, the corporate T1, and the DSL (if that will still even be available).
In the future, we may want to leave a spare mobile device at home or in the office to connect to the myriad IoT devices running there, but — in a world where people are still upgrading their phones frequently — there will be a lot of spare 5G-capable devices that can be applied in this way.
This is a wildly inverted world, where the ultimate end point — the mobile phone — moves past being the most used communication tool, and becomes the hub of all our communication, replacing a great deal of the 4G era and earlier infrastructure.
The implications are sweeping. This is going to change everything that we have come to understand in today’s model of connectivity, which will be revealed as a messy and wasteful way station, a midpoint transition from a 100 percent wired to a 100 percent wireless world.
This post was written as part of the Dell Insight Partners program, which provides news and analysis about the evolving world of tech. Dell sponsored this article, but the opinions are my own and don’t necessarily represent Dell’s positions or strategies.