Cell Phones, Wi-Fi, and Electromagnetic Radiation

All radio devices like cellphones, radios, televisions, and Wi-Fi devices communicate via electromagnetic radiation. These man-made devices are not the only source of such radiation – the Earth’s magnetic field, the Ionosphere, the sun, and the universe in general all emit similar electromagnetic radiation, over an extremely broad range of frequencies.

Electromagnetic radiation, which can be invisible like radio waves, visible like light, or felt like infrared heat, is subject to a law of physics called inverse-square. The quantity or intensity of any radiation is inversely proportional to the square of the distance from its source. The diagram below illustrates this principle.

Creative Commons licensed Image courtesy of Wikimedia user Borb



Just like when sitting around a fire, the closer a person is to the source of some radiation, the more exposure they will receive. The further away, the less exposure.

Levels of radiation from devices as absorbed by the body are measured with a standard called the “Specific Absorption Rate”, or SAR, which is a calculation of the energy absorbed by a person in watts per kilogram. In New Zealand, NZS 2772.1:1999 regulates a maximum permitted exposure of 2W/kg. (updated link 5 Jan 2014)

Online news provider CNet tests the SAR of mobile phones on a regular basis and stores the results in a database, which was last updated in July 2013. The mean score of their top 20 lowest radiation phones is .32, and the mean of their top 20 highest radiation phones is 1.43.

While cellular towers emit much higher power levels than cell phones, due to the inverse square law the amount of energy a person can absorb from them can be quite low. At ten meters, about as close as a person can get to a cellular antenna, the SAR of a 50 Watt GSM transmitter is .365, or just around the level of one of the lowest radiation cell phones on the market.

Such cellular tower radiation levels have been judged by the Environment Court (Shirley Primary School v Christchurch City Council C136/98) to be so low that the risk of radiation to students from a cell tower to cause sleep disorders or learning disabilities would be “in the order of one in a million”, and that “there was so little evidence for an adverse health effect from RF emissions that it cannot be scientifically calculated as a percentage probability in small fractions of a percent”.

Wi-Fi devices operate on power levels far lower than cell phone towers or Smartphones. While a cellular tower may emit 50 watts, a Wi-Fi router is restricted to 4 Watts or 1 Watt, depending on the frequency band in use. A recent study by the UK National Radiological Protection Board found that for a child in good signal range of a wireless router, the SAR at head level was 0.0057W/kg.

The table below summarises the various data:

[table id=1 /]

With 5,407,000 mobile subscriptions as of 2012, New Zealand has more active cellular connections than people. Many of these connections, including all of Telecom’s nearly two million, are 3G connections that support data alongside voice. Smartphones were in the hands of 44% of subscribers by 2012, and most of those subscribers use data on them every day. Smartphones also make up 58% of all new phones sold today.

One of the most common features of Smartphones is the ability to use data on Wi-Fi networks. When using Wi-Fi, the power levels absorbed by a user of a smartphone will be far lower than if the device is using 3G.

From the research cited above, it’s clear that if you’re going to use a Smartphone or allow one to be used near you, the best way to minimise radiation levels is to ensure that Smartphone is using a Wi-Fi hotspot for its data. Calling for the elimination of Wi-Fi from public places or schools on the basis of a radiation hazard is entirely misguided and counterproductive to a goal of lessening absorbed radiation.

Kordia Sale to Woosh: Spectrum Management Failure

Radio spectrum in the 2.3-2.5GHz bands is best known for use with broadband. It is the 2.4GHz “Public Park” that millions of New Zealanders use on a daily basis for Wi-Fi, Bluetooth, and other wireless data applications.

In 2007 when the sale of this broadband spectrum on both sides of the public band was contemplated, the Government of the day was worried about competition and the efficient use of the spectrum.

Cabinet has indicated a preference for strict acquisition limits and use-it-or-lose it provisions, in order to prevent spectrum hoarding and to facilitate the development over time of strong competitive conditions.” (Discussion Paper)

40MHz was set aside for regional providers while around 200MHz was put up for auction as national rights – with individual acquisition caps of 40MHz. Lots were sold at an average of $23k/MHz across the band, to a small list of New Zealand companies and one overseas investor – a subsidiary of Canada’s Craig Wireless.

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Coming up on six years later, none of the national spectrum rights are in widespread use. CallPlus subsidiary Blue Reach deployed a small WiMAX system in Auckland around the time of the Rugby World Cup, but has since swapped spectrum with Vodafone, necessitating a change in technology. Vodafone has not publicly expressed interest in using the spectrum, however a business case exists.

Meanwhile, the small bits of regional spectrum are in huge demand by operators who actually use it, but didn’t have the cash up front to participate in the auction process. In some parts of the country fights over use of that regional spectrum have become underhanded and acrimonious.

In 2011 a struggling Woosh was sold to Craig Wireless, erasing more than $100M in shareholder value. With government approval, that deal allowed Craig to take control of Woosh spectrum, bringing their holdings in the 2.3-2.5GHz band up to 70MHz.

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This week the landscape changed again, with government-owned Kordia selling its 2.3GHz rights to Woosh owner Craig, concentrating 45% of the national rights in the hands of Craig Wireless – a company unlikely to build in New Zealand as it struggles with a cash haemorrhaging local subsidiary and against a forceable de-listing from the Toronto Stock Exchange.

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The government’s policy of treating radio spectrum as a tradable property right has once again failed to bring a benefit to New Zealand. In the manner of Esau, the government has sold its birthright for a bowl of lentils. Now while homegrown providers like Araneo, Inspire, and Netsmart fight over regional crumbs yet deliver astounding benefits to rural New Zealand, an opportunist Jacob in the form of Craig Wireless has accumulated more and more unnecessarily fallow national spectrum.

Without significant change in radio spectrum management policy, New Zealand is destined to see the story above played out again and again, to the detriment of its people and industries.

NZ Radio Spectrum Landscape 2013

2012 brought significant change to New Zealand’s spectrum landscape in the form of multiple transactions involving radio spectrum management rights.

First, Vodafone and CallPlus entered in to a spectrum swap, converting two TDD blocks in the 2.5GHz range to FDD blocks compatible with UMTS Band VII.

Then Vodafone purchased TelstraClear, who held 150MHz of spectrum worth nearly $100 million dollars. As holding such a concentration of spectrum to the detriment of smaller players could be seen as a misuse of market power, Vodafone chose to leave some spectrum on the table in that deal. Telstra Australia then sold a 15MHz pair in Band III to 2Degrees shareholder Trilogy, and has kept a 5MHz pair in UMTS Band I.

The resulting spectrum landscape, detailed in the graphic below and in a downloadable wall chart, has increased the ability of both Vodafone and 2Degrees to deliver new and better services to New Zealand consumers.

In the chart, holdings of Telecom are shaded yellow, Vodafone orange, and 2degrees (including shareholders Hautaki and Trilogy) blue. The 700MHz Digital Dividend band likely to be auctioned in 2013 is shaded green. Common 3G/LTE cellular bands are noted to the right of relevant cellular holdings.

Download an A-series PDF wall chart for printing or easier on-screen viewing.

Spectrum Infographic Tall 2013-04-03 copy

LTE as Fibre Killer? Vodafone’s Quick Win for Fixed Mobile Substitution

Fixed Mobile Substitution (FMS) is the concept of replacing fixed telecommunications lines with mobile technologies.

In New Zealand the number of fixed lines in use has remained steady from 2006-2011. In Europe over the same period, the number of households without fixed lines increased from 18% to 27%. At the same time, penetration of broadband has increased in both markets.

High prices for data have kept New Zealand tied to its landlines for data while many Europeans have made the leap to all-mobile.

In support of high prices, New Zealand carriers have argued that spectrum is scarce, cellular equipment is expensive, and the cost of building towers is prohibitively expensive due to local councils and the Resource Management Act. As of this time last year all three carriers had the added operational expense of leasing fibre or Ethernet services to their towers for backhaul. These barriers have added up to networks that are generally running at capacity, with only high data costs to prevent users from overloading the network as in the case of Vodafone Australia.

All this changed in 2012 when Vodafone NZ made two strategic acquisitions. In May they performed a spectrum swap with CallPlus, converting what had been a fairly useless block of radio spectrum in to one compatible with a common variant of LTE. In October, the Commerce Commission approved their purchase of fixed-line carrier TelstraClear.

The TelstraClear purchase, in addition to bringing along a pile of radio spectrum, positions Vodafone as the only cellular carrier with their own metro fibre network. Vodafone has the added bonus of dense suburban reticulation through Christchurch and Wellington, in place to provide TV and broadband over a Hybrid Fibre Coax (HFC) system.

With metro fibre across most of New Zealand’s population and a new LTE network, Vodafone is positioned to be a strong competitor to UFB already. Their new LTE service using existing infrastructure is already twice the speed of the basic 30mbps UFB offering, but data pricing is being kept high to ward off network slowdowns. With a new fibre network and 2.6GHz spectrum, they could massively increase their network capacity without expensive equipment, tower builds, compliance costs, or backhaul OpEx using outdoor picocells. For example:

Pictures of four outdoor piocells installed
Alcatel-Lucent and Ericsson Outdoor Picocells enabling LTE coverage
  • Alcatel-Lucent’s MetroCell: A laptop-sized cell site designed to mount to a utility pole, requiring only 45 watts of power and IP backhaul and requiring no resource consent.
  • Alcatel-Lucent’s LightRadio: A distributed cellular architecture for 3G and LTE comprised of tiny, fibre backhauled cubes that are spread throughout an area on utility poles. They’re usable alone for low densities of users and stackable for higher densities.
  • Ericsson’s Bel-Air LTE Picocell: A laptop-sized LTE cell site that hangs from the same overhead coax lines that are used to provide cable TV – taking its power from the existing TV distribution network and using existing Ethernet services for backhaul.

All three can add an LTE sector of capacity to Vodafone’s network for less than $10k without new consents, tower leases, or backhaul costs. The Ericsson option could be rolled out to tens of thousands of customers in a matter of weeks. The combination of abundant spectrum, the ability to use cheap equipment, inexpensive or free access to utility poles as towers, and own-network metro backhaul are unique amongst New Zealand carriers.

Table comparing Vodafone, 2Degrees, and Telecom advantages
A Year Has Changed The Game

Using LTE picocells to provide increased network capacity, Vodafone could easily offer products in to the market with UFB equivalent speeds – without any of the startup costs or long-term contracts required for fibre installations. Given the savings over paying an LFC $37.50/month for a UFB circuit, shifting just 5% of the fixed broadband market on to an LTE solution could add an extra $26M p.a. to Vodafone’s bottom line.

LTE Picocells + New Spectrum + Metro Networks could be a quick win Vodafone, who now have the option of providing a “Fibre Killer” solution.

Kordia’s Strategic Review

Kordia are undergoing a strategic review as reported by Computerworld. It’s about time. Kordia could have been the shared infrastructure company of New Zealand’s wireless ecosystem – as dominant and profitable player as Chorus is set to be on the fixed line side of things.

Instead of sticking to its core business of maintaining towers and transmission to a high standard, Kordia attempted to grab everything it could. Gallingly, in almost all the cases of their numerous commercial failures, they went head to head with their existing infrastructure and wholesale services customers instead of cooperating with them. And they did so with appalling personal and organizational arrogance.

The bigger failures:

  • Metro Wi-Fi network that didn’t meet the needs of its users
  • Rural wireless product that had massive functional issues
  • Metro wireless Ethernet product that was expensive and based on dated technology
  • The KorKor network – inferior coverage to TeamTalk and inferior technology to Telecom’s XT.
  • AIS network – too little, too late, and too expensive for many harbourmasters and port companies
  • OptiKor – might have done well but since handed off to Axin, a secretive shell company hiding secretive inves* tors
  • A strident bid for the government’s Rural Broadband Initiative that had them partner with Woosh and FX, which featured unbelievable technological claims

Aside from DTV (and remind me who paid for that) where have they headed in the right direction?

  • Offshore contracts – bringing cash back to NZ. Nice work.
  • OnKor Wide Area Network Services – a technically excellent product taking advantage of fibre rights held from the Clear days and a microwave network built to move television broadcasts around – complimentary to Orcon
  • Odyssey – control international transit and you can provide QoS to your customers – nice long term partner to Orcon
  • Orcon – a real competitor in the market, but are Kordia committed to it long term?

Keeping in mind that Onkor and Orcon compete against Kordia’s wholesale clients, and Odyssey is most useful as a part of that ecosystem, here’s some strategy:

1. Package Orcon, OnKor, and Odyssey up & divest them. Stop competing with the best potential customers of your huge (and maybe overvalued) asset base.

2. Go to Vodafone, Telecom, & 2degrees, JDA, local councils, and other tower owners, hat in hand, and say “hey guys, we know we screwed this up a few years ago, but from now on how about we start working together on tower and transmission infrastructure. Oh, and LTE with its 700MHz rural towers and high density 2500MHz urban microcell requirements might be a great time to start”

That would be a good day for Kordia, and its owners, the people of New Zealand.

Vodafone & CallPlus Swap Spectrum for LTE

Vodafone and Blue Reach, the wireless subsidiary of CallPlus, have traded blocks of spectrum in the 2.5GHz spectrum band. The trade will allow both carriers to operate Long Term Evolution (LTE) networks using standard frequencies supported by hundreds of phones and broadband access devices on the market today.

Although not yet announced or reported by either company, the swap was recently registered in the Ministry of Economic Development’s SMART database, with commencement of the change 30 May 2012. Just nine days before this license change, NZTelco commented on unusual activity in Vodafone’s 2.5GHz spectrum band, and speculated on what Vodafone might be doing. A spectrum swap was not foreseen or discussed.

Prior to the spectrum swap, Vodafone and CallPlus each held single blocks of spectrum suitable for use with Time Division Duplex (TDD) WiMAX or LTE band 41, a recently ratified band for which no base stations or mass market devices are yet produced. CallPlus had been operating a WiMAX network using their spectrum in Auckland, and Vodafone had not used their spectrum for anything. The diagrams below show a “before and after” picture of the 2.3 & 2.5GHz spectrum bands and how they were affected.

Since the swap, both providers now have 15MHz pairs in LTE Band 7, a key band for offloading data traffic in congested urban environments. The utility of such spectrum is immense, especially to Vodafone, who have a higher user to deployed capacity ratio than either Telecom or 2Degrees Mobile. 2.5GHz spectrum has very small cell sizes, high capacity, and high potential for re-use. It is likely to be used in the most crowded of locations to take pressure off of Vodafone’s network in areas of peak demand.

The alignment of the spectrum with an internationally supported band is also important. The map below shows countries where LTE Band 7 networks are active today. With a 2.5GHz LTE network Vodafone could offer lucrative LTE data roaming services to users from these countries.

Band 7 is likely to be the most common band for in-home and in-office LTE Femtocells, and is today the best choice for providing LTE to crowded locations like train stations, conference rooms, and sports stadiums. Vodafone’s spectrum swap with CallPlus can only mean good things for its customers.