What are 4G networks?

01 January 2009 |


The concept of 4G is bandied about with increasing frequency.

But other than the obvious fact that 4G will be some sort of step up from 3G, many people remain hazy about what to expect from it and when.

There are a few standards in development that are being tipped as offering 4G capabilities. What links them is the promise of speedy broadband wireless capability over IP, with data moving at a rate of around 100Mbps, and going up to as much as 1Gbps. This means we should expect the sort of performance currently offered by fixed Ethernet links to the desktop in our mobile devices.

In one version of a 4G future, every sort of device imaginable will have its own IP address, not just mobiles and laptops, but practically anything electronic. These devices will then be able swap data or at least communicate with any other device no matter where users are located. High quality video will be streamed anywhere at will. Many see the initial 4G battleground as developing countries where, with IP offering a universal service platform, services should come in at a relatively low cost, meaning users will choose to bypass 3G adoption altogether. Not all agree that wider 4G adoption will be fast: “Investment in 3G, following the spectrum auctions of 2000, will mean that a rapid migration to 4G is unlikely – however much it is hoped for,” says John Thornton, product architect for unified communications with Telindus.

What are the key emerging 4G standards and how do they compare?

A number of vendors and operators are currently trialling Long Term Evolution (LTE), talking it up as the obvious successor to 3G. But LTE doesn’t have the 4G field to itself. Mobile Wimax (802.16e) is a widely supported alternative. Ultra Mobile Broadband is also considered a 4G contender, as is HSUPA, the upload cousin of HSDPA.

LTE benefits from its evolution out of hugely popular GSM technology and offers theoretical data rates of up to 173Mbps. Mobile Wimax by contrast currently tops out at 70Mbps, but has around a two-year head start in actually getting to market. The fastest mobile broadband technology currently available is HSDPA with around 7.2Mbps, so clearly any 4G option will boost performance hugely. Fixed Wimax is available as a commercial service and mobile Wimax has already been made a part of 3GPP, while LTE is set to be included in 3GPP Release 8 in late 2008 or early 2009.

Who is backing which standard?

Mobile Wimax, though ahead of LTE in actual use, is still unproven on a large commercial scale. Although early in its development, LTE is expected to be Goliath to Wimax’s David, so widely is it supported. A number of operators have announced their support for LTE. But many are also planning mobile Wimax networks while they decide which path to commit to longer term. Vodafone says it will roll out LTE by 2010.

Vendors also are in both camps. Alcatel-Lucent and NEC are combining resources and looking to release LTE products by 2009. Nokia Siemens Networks has carried out a field trial of LTE in an urban environment. It said the tests proved that future LTE networks can run on existing base station sites, so mobile operators can build new networks without needing new antenna sites.

Is a standards war inevitable?

Analysts and industry insiders are concerned about the impact of a technology standards war between Wimax and LTE. There have been many calls for the avoidance of a split between two technology camps.

There’s a school of thought that considers it too late to merge the Mobile Wimax standard with LTE, with too much progress already made on the road to commercial availability to start tinkering now.

Have LTE and Mobile Wimax got anything in common?

LTE and Wimax use similar Orthogonal Frequency Division Multiplexing (OFDM) technology and multiple-input multiple-output (MIMO) technology, based on the use of multiple antennae. Theoretically both can use the same hardware on a single board, with different Wimax and LTE layers managed with software. R&D efforts may result in femtocells for the home user that can support Wimax or LTE.

What happens to tariffs in a 4G world?

In a 4G world, fixed-price mobile phone bills will likely become the norm for customers, reflecting changes in the way they use mobile services.

The death of traditional usage-based billing will have consequences for operators. It may very well impact on their profitability, the very reason why the idea of flat rate services has been hitherto rejected. Backhaul naturally presents another area of operator concern.

Naturally the volume of bandwidth required for the delivery of mobile services will tend to increase exponentially with a move to always-on pricing, as users leave connections open for hours at a time.

User demand will no doubt be a key determinant in 4G’s popularity. The early signs of how this might manifest are there – with the advent of the iPhone, the concept of using the internet on the move has been given a phenomenal boost. Key too is the launch of Web 2.0 services for mobiles such as Skype, Ebay, and Facebook.