Networking

Wireless bands are old tech: For mobile's sake let's abandon them

Today's wireless systems are mired in analogue legacy stretching back 100 years. Splitting the spectrum into bands is something that we can drop to great advantage.

Written in my Singapore hotel room and despatched to TechRepublic at 60Mbps over a wired LAN.

Digital signal processing has changed everything in our lives - from the cars we drive, the products we manufacture, and the way we communicate and calculate.

It has also given us the internet and mobile technology. Yet that wireless technology is still based on designs that evolved between 1915 and the 1970s.

A continual process of refinement and miniaturisation - technology polishing, if you will - got us to where we are today, with the added innovation of digital processing technology. But now we find ourselves at a watershed where new techniques are required for any really significant gains.

The use of bands - splitting up the spectrum into convenient chunks for radio, TV, citizens' use, police, cell phones and so on - could now be replaced by everyone using the same frequencies at the same time.

The interference problems that we would have suffered with analogue technology can now be overcome by digital coding and processing.

A physical analogy would be our ability to talk over the noise of a crowded cocktail party and yet hear nothing at all of the other conversations going on around us.

How is this facility possible for wireless systems? It is a bit of a challenge to explain, but here goes.

Figure 1 shows the analogue banding that separates the energy of one signal from another.

Figure 1. The analogue past of wireless bands. Image: Peter Cochrane/TechRepublic

Figure 2 shows those bands removed and all the signals overlapping.

Figure 2. The digital future of wireless using codes. Image: Peter Cochrane/TechRepublic

So how are they separated? They are separated by time and angle.

Why is this important? Looking to the future, we can expect an internet of mobile things far in excess of the mobile devices that humans own. These things will be fixed and mobile, long- and short-lived, and they will need to communicate with each other and networks.

The wireless technology of today will not do the job. We will need every ounce of bandwidth and every degree of signal separation we can muster. Removing bands, and spreading signals over a greater span will provide that facility.

If we had no radio systems at all and were starting with a clean sheet of paper, all these issues would pose no problem. But we don't.

Legacy technology and investment

We have a huge investment and deployment of legacy technology and replacing the old with the new will take some considerable time.

However, there is some good news. The internet of things will mostly involve short-range communication at low power. The spectrum available for that type of communication is well above that used commercially today. It also offers more than 1,000 times the capacity.

Another perspective is the transition from a kW world with thousands of huge masts and big transmitter powers serving millions of radios and TVs, to thousands of mobile base stations at more modest powers measured in watts with millions of users, and then on to billions of mobile devices and things with billions of base stations at very low powers measured in mW and uW, operating over very short distances in continual and sporadic modes.

Figure 3. From megawatts, kilowatts and watts to millwatts and microwatts. Image: Peter Cochrane/TechRepublic

What happens after that? A migration of the spreading technology, one service band at a time, until the entire spectrum is covered. How long will the process take? Looking at the recent move from analogue to digital TV it could be as long as 20 years and as few as 10 or less once it starts.

After that we have nowhere to go. We have come to the end of the evolutionary road for wireless systems. Of course, added intelligence will be complemented by smart antennas and more processing power, but the basic technology cycle will be sealed.

The radio spectrum, in total, spreads over some 300GHz, but we have only used around 30GHz so far. Then, of course, there is free space optics, which is millions of times greater.

As we extend into the space above 30GHz, there is some really good news. Atmospheric absorption accelerates and communication over more than a few metres or hundreds of metres rapidly becomes impossible and the mutual interference problem dies away quickly.

This is ideal for the future we are building with billions of wireless devices, and we are working symbiotically with nature rather than trying to go in the opposite direction.

What does it all mean for you and me? Improvements in our lives and living, invisible and visible. How big a change?

I reckon it will be about the same size as the move we experienced from those first transistor radios to the internet - or perhaps even bigger.

About

Peter Cochrane is an engineer, scientist, entrepreneur, futurist and consultant. He is the former CTO and head of research at BT, with a career in telecoms and IT spanning more than 40 years.

15 comments
MWRadio
MWRadio

I find it hard to effectively state a rebuttal for a man with your credentials but I find I must do so. 1.)"Removing bands, and spreading signals over a greater span will provide that facility." Wrong! Removing bands only removes current users. Much of the current bands in the lower frequencies are totally unsuitable for high volume multiplexed (multi-subchannel) digital signals because the wavelength is just too long to reproduce high speed digital streams! How can you produce even a single 100Mbps (Million bits per second) digital signal on a 28Mhz (Million Cycles per second) carrier frequency? Answer: YOU CAN'T! If you attempt to modulate a signal faster than its carrier frequency it becomes a higher frequency signal all on its own! So why destroy those legacy bands for the users? No good answer has ever been given by anyone proposing the destruction of legacy "HAM" and so called shortwave bands. 2.) "The radio spectrum, in total, spreads over some 300GHz, but we have only used around 30GHz so far." Right. That is mostly because semi conductor technology is not up to breaking into the higher frequency ranges. Transistor response is a limiting factor in transmitting signals in Multi GigaHertz ranges, not government policy. When we have the technology we will move there. It is coming, albeit slowly, but these are totally new bands coming into use that have not been used before, not stolen from other uses! 3.) You hold up the recent conversion to digital TV as an example. I would not find that crappy move an example of progress if it was me. I had twelve channels I could receive with analog TV. All were viewable 24/7/365. Sometimes with a little noise in the picture BUT VIEWABLE! Now I have twelve channels in my program list (Totaling 31 subchannels!) ten channels of which work sporadically or not at all most of the time. Try watching a movie in which you see ten minutes then for two there is nothing but digitized garbage video, blip, blip, blip of audio, then "no signal" for five, then back to blip, blip, blip, then maybe some of the show. REALLY ENJOYABLE ISN'T IT? ALL of my neighbors are in the same boat. Its not just me! Better antennas, Coaxes, added amplifiers, rotors, HUGH EXPENSE! NO HELP! We are all fed up with it but what can we do? Now you're going to let the same idiots ruin my internet? THANKS, BUT NO! Don't even get me started on cell phones! Someone calls me, we talk a few seconds and then I hear them saying, "Are you there?...Are you there?" or else there is dead air for a while while I ask, "Are you there?...Are you there?" Click, buzz. They call back, "Where was I when I lost you?" repeat ad nauseam until a conversation is (maybe) completed. Get a clue people! Its your wonderful, DIGITAL, phone, not my land-line, that is dropping the calls! I used to have an analog cell phone. It almost always worked. I won't (and Don't!) own a cell phone that works as bad as every one I have had to deal with recently. Now you want to add that "reliability" to my internet too? No Thanks! Do your dream work in the new frequencies that are opening. LEAVE existing, working, systems ALONE until you have your dream system WORKING, RELIABLY! And I can't stress this word enough... PLEASE!!!!!!!!!!! We beg of you!

Tech--Republic
Tech--Republic

I'm all for applying new understandings to wireless signalling but that's only part of a much more fundamental transition. As I write in http://rmf.vc/PCASTless the first step is to remove the artificial distinction between wired and wireless bits. We also need to recognize that the signal as understood by EE's (bits) and signal in the sense of humans talking are essentially unrelated. This is one of the concepts underlying the Internet -- we need to be careful about confusing it with a telecommunications industry dating back to the days of telegrams.

mafm71
mafm71

An idea was born in my head as I was reading your article ... Do you think that after many years of constant and ever growing amounts of radiated energy, it could also affect the atmosphere, adding the radio/TV/telecommunications to the world heating problem that affects our world ? Lets remember that there is always a certain amount of energy absorbed by the atmosphere according to physics laws.

geofer50
geofer50

Sounds great in theory, but it is putting all of your eggs in one basket. We need to to advance and I agree with that, but we need to maintain versatility for the whole band system. As I see it the manufactures benefits the most as with some benefit coming to the consumer. It will give the manufacturers great profits while filling the land fills with obsolete devices, and yes there is a recycling program, but face it not everyone participates in it. It will also consume our valuable resources at a quicker rate as every new product that comes out will require people to abandon their current devices to buy the latest and greatest gadget. Look at the Ipod with the change in connectors, it means more money for the manufacturer for all of the add on devices! And this is just one facet to the whole situation. Go down to your local flea market and see how many analog TV sets are waiting for a new home or worse the scrap heap. Now I am not against making money, nor am I advocating the end of the current spectrum, but I think there has to be a compromise where one can have a device to operate on a segment of bandwidth where everyone can enjoy. In the end, I see this as a greedy grab for control of the media / air waves where power and money will go to a select few who want to reduce the free spectrum that we have now to a pay up or you don't get to listen deal.

bboyd
bboyd

Maybe they don't mind if the police, fire, ambulance or any other public safety agency has a reliable long range voice communication. I understand that in metropolitan areas digital systems work well, at least until they get overloaded like NYC during 9/11, but in rural areas its not ok. Oh and just guess what happens during wartime to all those minuscule transmissions start facing electronic jamming. They can thank military frequency agile spread spectrum transmitters for the technology then ignore the realities that produce them.

peter
peter

I have worked on this for decades - so I have thought bout it a bit ! "We have a huge investment and deployment of legacy technology and replacing the old with the new will take some considerable time" "What happens after that? A migration of the spreading technology, one service band at a time, until the entire spectrum is covered. How long will the process take? Looking at the recent move from analogue to digital TV it could be as long as 20 years and as few as 10 or less once it starts" AND BY THE WAY - it is already being practiced by those who want to communicate without being detected.

peter
peter

I do wish I could understand this !!

peter
peter

NO! Worry about the sun and hydro carbons. Radio waves are (litteraly) in the noise :-)

bboyd
bboyd

In the electronic warfare specialty we referred to many of our transmitters as "free birth control". Those tissues are especially sensitive to EM radiation heating and suffer damage sooner. Of course they are high power affairs generally several orders of magnitude more powerful than consumer devices. https://en.wikipedia.org/wiki/Association_of_Old_Crows The waste heat from power plants is far more environmental heat than EM transmitters make.

peter
peter

You need to read up on Spread Spectrum - it does entirely the reverse of what you suggest in terms of using a valuable resource - and we are talking migration here and not a sudden leap for real estate!

Deadly Ernest
Deadly Ernest

very widespread unlawful dumping of obsolete gear because most countries now have laws in place about the recycling of tech gear and that means the poor user often has to pay to have the old gear processed. People who are flat chat having to come up with money to buy the new gear will just dump their old gear beside the road while out on a country drive, or toss it over the side of a bridge.

peter
peter

People, companies, societies find it hard to let go of the past and the established - change is never easy - but this will happen a step at a time. How many peopl know that their mobile phone uses Spread Spectrum technology developed during the cold war....and do the care? Apparently not until you suggest getting rid of AM, FM, SSB et al :-)

peter
peter

That is another dimension of another problem set that this technology will change. Everyone can now have a radio and TV + mobile +++ Soon a world of connected things will demand a new mode that includes recycling in new way orchestrated by tagging.

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