Mhz-Ghz limited range availability?

nmop_apisdn

Hearing alot about this lately but curious, why is their a spectrum squeeze?

Is it tech limitations?

oscarBravo

nmop_apisdn wrote: »

Hearing alot about this lately but curious, why is their a spectrum squeeze?

Is it tech limitations?

Sort of. Radio technology has just about come up against the laws of physics in terms of the amount of data that can be transferred across a given bandwidth of radio spectrum, which means that the ever-increasing demand to transfer more data requires more spectrum be used to do it.

watty

But Physics sets the really useful spectrum for Mobile as about 900MHz to about 2.5GHZ (2500MHz).

Above 2500MHz the range and building penetration gets poor, 3.5GHZ (3500MHz) proven to be nearly useless for Mobile/Indoor. Needs chimney aerial / Dish.

Below 900MHz the amount of spectrum per band is too low and the distance is unpredictably too high, which causes a problem for Mobile as it reuses the same frequencies in different places.

GSM using Edge V2 and 3G / HSPA are close to the practical limit of spectrum versus speed for Mobile. The oft quoted x4 higher speed for LTE/4G is a con as that needs a x4 bigger channel! 20MHz vs 5MHz.

GSM seems slow because the basic version uses only 0.2 MHz per channel.

So Mobile can only have more spectrum by taking it from other applications such as TV.

Other applications need some of the spectrum 900MHz to 2500MHz. (GPS, Digital Radio, Satellite, DECT cordless phones, Rain Radar, Video Senders, WiFi etc).

Mobile doesn't actually need more spectrum. That is the lazy and cheap for the operators and high value for Treasury / Regulator as they sell more spectrum and Mobile companies will pay more than anyone else. In the UK they are taking internationally agreed frequencies from Radio Amateurs and Military and reselling it to Mobile.

There are two ways the existing spectrum in use by Mobile can give a Staggering x10 more average capacity:
1) Have only one Wholesale operator. With present system at one place Three could be overloaded and 02 using no channels and vice versa elsewhere. A single wholesale operator can increase average performance by x3 to x4 or more.

2) Combine Bands to one operator as above.

3) replace 3 masts with 9 masts or more. The more masts the LOWER the power, about x4 phone battery life, x2 to x4 more average speed etc. Ironically the new 800MHz band is rubbish for increasing capacity this way but hardly used 1800MHz and the 3G 2100MHz are good. The proposed 2500MHz (2.5GHz) which is allocated to mobile 4G but used for MMDS (a Local Irish Decision instead of "proper" MMDS frequencies) is even better, you could have x12 as many masts at about 1/15th power or less and about x8 more capacity on average.

The more masts there are the lower down they can be and the less power. Masts are safer than phones (because the Radio power on your head about 1000 times lower) even if there was a risk (which has never been proven). More masts means the phones run at dramatically lower power and have longer battery life.

nmop_apisdn

Thanks for the very informative replies guys!

bengii

Thnx ! Great info.

I get ur point on capacity being utilised better using a wholesale approach, but not sure about the point with more masts.

Is that because wholesale operator could manage interference and planning better?

Also, if there are higher throughputs then that will definately reduce UE battery life, right?

watty

Less Masts needs more channels (spectrum) and more power. Double the range per mast needs x4 power on handset/dongle and mast.

More Masts is 1/4 to 1/10th power as range need is much less. No extra channels (spectrum) as the further away channels are re-used. The more masts the fewer simultaneous users on each mast, so those users get more speed (simplistically if there are 1/4 the number of users you get x4 speed)

Low frequency band (800MHz) have inherently less channels possible than high frequency band (2100 to 2600 could have x4 as many channels as 800MHz), yet the physics of Radio Propagation says you need MORE channels at 800MHz than 2100 to 2600 MHz bands. Thus 800 MHz is low capacity, any realistic number of simultaneous users would give about 1/10th or less of the performance possible on higher bands.

1700 MHz to 2700 MHz isn't continuously available in one block, but it's possible to use the separate bands in it in one phone handset, tablet or Dongle and have about x5 spectrum of 800 MHz band and due to ability to have lower power masts closer together the total capacity could be x10 or more of 800MHz and 900MHz bands combined.

The spectrum is a fixed quantity. Only a tiny portion of it is suitable for mobile. But most of the spectrum Mobile has already is badly used. So why sell them the 800MHz TV band?
Greed. It's cheap for operator to extend coverage (but at poor capacity) and allows Regulator to raise money (once off hit) to Treasury.

The Regulator deliberately doesn't impose a single Wholesale Mobile operator as they would only get 1/4 of licence revenue.