4G and LTE – The future of Mobile

The Mobile services we use today are controlled by a series of International Standards, which constantly evolve to reflect the rapid changes in technology.

Whilst these standards are very technical specifications, specific terms like 3G, 4G and LTE are used by marketing groups to promote mobile phones and services.

This section tries to clarify exactly what those terms mean.

The beginning

Set your mind back to 1984 and the iconic Motorola DynaTAC 8000x first ever mobile phone, weighing in at a solid 2lbs(a bag of sugar) and costing a tad over £3000.

Happy days, when ‘The brick’ allowed someone to make a mobile phone call, and that was all.

Various standards bodies were formed to produce specifications for different parts of the mobile communications network,  and these came together under the 3rd Generation Partnering Project(3GPP) to produce a series of Releases against which mobile communications equipment is specified.

See  www.3gppp.org

Within these Releases, individual specifications cover everything from mobile phones, air/spectrum interface, Cell Tower and Internet Access etc.

The contributing standards bodies include:

  • International Telecommunications Union( ITU)
  • European Telecommunications Standards Institute (ETSI)

The early  G’s

The easiest way to think of this lot is as follows:

  • 1G – basic analogue mobile services – circuit switched(GSM)
  • 2G – shift from analogue to digital and the introduction of the first data service including SMS/Texting/Slow Internet. – packet switched (GPRS)

These G’s take us up to Release 4 of the 3GPP standards. Now it was time to consider full Internet services to our mobile phones.

Today’s G

3G delivers high speed Internet to your mobile phone.

3G services are being rolled out nationwide.

This involves transforming what where Voice based mobile networks into Internet access platforms.

Here are the basic elements:

U-TRAN – Universal Terrestrial Radio Access Network, defines the technology components from the mobile phone, to the Cell Tower(Node B) and onward to a RNC(Radio Network Controller)

A key component is the radio transmission, or HSPA – High Speed Packet Access(the key is the word Packet in which Internet traffic is transported).

There are two version :

  • HPSA – provides download(to your mobile) speeds of up to 14Mbps
  • HSPA+ – which increases that speed up to 84Mbps

Because of these new requirements, each country had ‘ 3G Spectrum auctions’ (UK’s was 2000) to release more frequencies to support these services.

The RNC(responsible for radio resource and some mobility management) then hands all circuit switched traffic to the Media Gateway(MGW) and all packet switched traffic to the SGSN(Serving GPRS Support Node). The SGSN handles the routing of Internet traffic to and from the appropriate mobile phone, whilst it’s upstream partner the GGSN(Gateway GPRS Support Node) deals with the communication with the Internet.

Effectively your 3G services are covered by Releases 5-6-7 of the 3GPP standards.

Long Term Evolution(LTE) and it’s mate 4G.

If you delved into the GPRS architecture in any details, you would see it is complex, expensive to run and does not scale.

By scale, I mean cater for the explosion of Smart phones requesting huge amounts of data(Internet).

So, why not develop a system that mirrors the broadband services you get in your home. These are All-IP, meaning the Internet Protocol(IP) runs all the way to your home hub, and on to the attached devices like laptop, Xbox etc.  See section Internet Explained.

If we simply put a Broadband hub(router) at each Cell Tower, bypassed the GPRS and ran all the traffic to the Internet, including Voice-over-IP(VoLTE), then we create a much simpler network, that mirrors what the communication companies already have deployed in millions of homes and business around the globe.

This is the System Architecture Evolution(SAE).

The key components are as follows:

Evolved Universal Terrestrial Radio Access Network (E-UTRAN)

If the 3G HSPA+ offered 84Mbps, E-UTRAN offers just under 300Mbps.

The key is that it offers a far more efficient way of using the available spectrum(frequencies) which the mobile operators require to offer a range of video/data services.

Mobility Management Entity(MME) and Serving Gateway(S-GW)

The easiest way to think of these two is:

MME handles the call set up and clear down information coming via the E-UTRAN, whilst  the S-GW handles all the IP Packets from the E-UTRAN out to the Internet, including any changes as the user moves between Cell Towers(Masts).

The S-GW also handles the interface between LTE and 3G networks.

PDN Gateway(PGW) 

The 4G standards actually include how additional technologies like Wi-Max and Wifi fit into a complete communications strategy.

The PGW’s roll is to accommodate a mobile phone which might also use Wi-Max to communicate.

LTE and SAE are covered by Release 8 of the 3GPP standards.

A catch-all Release 9 allowed for various updates in the overall mobile standards.

4G

Before we start, LTE is technically not 4G, because 4G specifies a download speed of 1Gbps.

The marketing folks have completely ignored this and promote LTE/4G services.

Within the 4G standards there is something called LTE-Advanced, which will meet those speed requirements.  Hence LTE is often referred to as 3.9G…..go figure.

4G is targeted at converging all the various wireless communications methods into one seamless system.

The technologies include:

  • LTE Advanced
  • Wi-Max
  • Wi-fi

4G is Release 10 of the 3GPP standards and was released in the first quarter of 2011.

Ofcom – the UK telecommunications regulator is due to hold a ‘4G spectrum’ auction in 2012. A portion of that spectrum is what was used for the old Analogue TV transmission.

Release 11 is scheduled for the end of 2012

Two spoons of reality vicar!

The new iPhone 4s has a download rate of 14.4Mbps.

According to the latest opensignals report http://www.opensignalmaps.com, the average speed of the UK 3G network is 1.6Mbps.

To receive LTE services you would need an LTE ready phone and they are limited

The UK has yet to auction off the 4G spectrum’s.

Everything so far has been trails like O2 in London.

The lack of fibre deployment in the UK will limit the roll-out of high speed Internet connectivity.

Worldwide, the primary driver for LTE in the short term will be Dongle services attached via a USB port to your laptop or LTE routers, both of which can actually handle the high speed data download capability.

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