Full disclosure time: I’m a stickler for standards – standards that do what they say, when they say. I continue to be saddened by attempts by operators to market LTE, WiMAX and even HSPA+ as ‘fourth generation’ wireless. I was dismayed when the ITU, presumably under considerable pressure from the industry, suddenly announced that is was okay for LTE et al to be regarded as 4G, and that 4G didn’t just cover technology that would meet its IMT-Advanced criteria.
Remember the story of King Canute? Well, the tide of mobile technology waits for no man, and we pedants were met with a tsunami of indifference. So who cares anymore? Want to brand your new mobile service as 5G? Go ahead, there’s no-one to stop you now.
All of which brings us on to the news that the ITU has finally agreed the specifications for its IMT-Advanced standard. At a meeting of the ITU Radiocommunication Assembly in Geneva yesterday, IMT-Advanced was ratified and the two remaining technology proposals were accorded with the official designation. To say ‘finally’ implies that there was a delay, but the truth is that yesterday’s date was set way in advance, as part of a stringent and rigorous evaluation process. It’s commendable that the ITU continues to devote time and energy into creating rock-solid standards with global backing. If only the consumer-facing side of the business would play ball.
The winners, of course, were the 3GPP-supported ‘LTE-Advanced’ and the IEEE-supported ‘WirelessMAN-Advanced’ – evolutions of LTE and WiMAX respectively (side note: WiMAX is the commercial brand of the IEEE 802.16 family of standards, also known in technical circles as WirelessMAN. And no, it doesn’t stand for Wireless Max, but ‘worldwide interoperability for microwave access).
Cast your mind back over a decade and you may remember the ITU’s earlier IMT-2000 programme, which established the family of standards that made up 3G technology. In fact, the ITU has been developing IMT (International Mobile Telecommunications) for over 25 years. IMT-Advanced is, as the name implies, the next generational extension of that. But with these technology leaps taking so long, there was ample time to evolve 3G technology. For example, following the W-CDMA path, we soon had HSPA and HSPA+, which gave more realistic 3G capabilities and created obvious distance between it and 2G GSM. Just lately we have seen LTE enter commercial service – perhaps better described as 3.75G, but who cares about numbers anymore?
LTE-Advanced, and its WiMAX-derived counterpart (for any remaining operators still interested in something other than the GSM family), promise to take mobile technology to the next level. ITU Secretary-General Dr Hamadoun Touré said the announcement was a landmark development in mobile technology:
“IMT-Advanced marks a huge leap forward in state-of-the-art technologies, which will make the present day smart phone feel like an old dial up Internet connection. Access to the Internet, streaming videos and data transfers anytime, anywhere will be better than most desktop connections today.”
François Rancy, Director of ITU’s Radiocommunication Bureau, explained what the new technology would be capable of offering to users:
“IMT-Advanced would be like putting a fibre optic broadband connection on your mobile phone, making your phone at least 500 times faster than today’s 3G smart phones. But it’s not only about speed; it’s about efficiency. IMT-Advanced will use radio-frequency spectrum much more efficiently making higher data transfers possible on lesser bandwidth. This will enable mobile networks to face the dramatic increase in data traffic that is expected in the coming years.”
Looking back over the IMT-Advanced programme, there were once six candidate technologies in the running.
Or rather, most were derivatives of either LTE or WiMAX. They were whittled down to the two we have today back in October 2010, and work then began on stress-testing them to see if they would hold up.
In March 2011, the IEEEE Standards Board gave its seal of approval to the 802.16m WirelessMAN-Advanced air interface (strangely, this was after it had been accepted by the ITU…). Incidentally, there is also an 802.16p variant being developed specifically for M2M applications.
Later in 2011, the ITU’s Radiocommunication Sector completed its assessment of the two candidate technologies, and submitted them to the Radiocommunication Assembly for final endorsement by the ITU Member States – which occurred yesterday.
The ITU set the target transmission rates for IMT-Advanced at 100Mbit/s when used in a high mobility environment (e.g. driving in a car) and 1Gbit/s in a stationary environment (oldies may remember that a 1Gbit/s top speed was touted ten years ago for 3G – but was only realistically achievable if you were next to a base station on a desert island with no other human life in clear weather and when flying pigs soared in the sky).
Leaving transmission speeds to one side, an equally important aspect of IMT-Advanced is that there is global harmony for the new frequency bands (there are seven of them, ranging from 450MHz to 3.6GHz) – otherwise roaming problems arise. Having been used to global interoperability in recent years, no-one wants to go back to the dark days of incompatibility between countries. Unfortunately, this is not quite fixed as well as the ITU would hope. Here’s how Stephen Blust, chairman of the ITU-R Working Party 5D (IMT Systems), describes the situation:
“To the extent possible, ITU has sought to harmonize the use of these IMT bands on a global basis, although in some of these bands and in some parts of the world such harmonization has not been able to be achieved because of the conflicting requirements of other radio services.”
Then there’s the issue of the amount of available spectrum, which leads to the amount of available capacity. According to Blust, actual data traffic in 2010 was more than five times greater than some of the estimates prepared for the ITU’s 2005 report on traffic predictions:
“Not only that, but in 2011 some operators even experienced a higher level of actual traffic than forecast for 2020. Even with the significant leap in spectrum efficiency available in IMT-Advanced, it is apparent that the overall amount of spectrum currently identified for IMT might not be sufficient for the future.”
To fix the looming problem, a number of ITU Member States are now considering proposals for the next World Radiocommunication Conference (WRC-12, which starts on the 23rd of January) to address future spectrum requirements for IMT mobile broadband.
Roberto Ercole, Senior Director of Spectrum at GSMA, says that WRC-12 will start a three-year period of debate, research and decision-making that “will shape the face of mobile broadband for decades to come”. However, it’s a long and drawn-out process. There first needs to be an agreement at WRC-12 to place an item on the agenda of the next WRC meeting in 2015. If that’s successful, and there is also a successful outcome at WRC-15, it would be 2025 or later before new spectrum becomes available. Who’s going to predict the requirements of the market 13 years from now? As Ercole says:
“There are very long lead times between allocation and identification at a conference and the final use of the spectrum by consumers. Given the importance of mobile broadband applications to all consumers, actions must be taken now to approve an agenda item at WRC-12 for IMT, and ensure that work between WRC-12 and WRC-15 is carried out as efficiently, affordably and inclusively as possible.”
Interestingly, an ITU background briefing document (un-credited) has this to say about the nomenclature mess:
“The term 4G remains undefined but it is being applied by operators to the forerunners of IMT-Advanced technologies — LTE, HSPA+ and WiMax and to other evolved 3G technologies, which provide a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now deployed.”
No surprise then that the term ‘4G’ is absent in all recent communications…
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