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.

Sending Party Pays for Bridging the Digital Divide

While many New Zealanders are considering the jump from copper to fibre broadband, many more aren’t considering either. It’s not that they don’t want broadband for themselves or their children, it’s because they can’t afford it.

In a report published in April, Statistics New Zealand estimated that 331,000 households don’t have broadband Internet access. A third of those households cite cost as the main reason. More troubling is that 63,000 households with dependent children don’t have access to the Internet because of cost.

Statistics also noted that 215,000 households don’t have landlines, but didn’t break down the reasons behind this. In Australia, 40% of mobile only households cited cost as the reason for not maintaining a fixed line. Going mobile only can be a huge cost saver if all you want to do is call and text. If New Zealand follows the lead of the European Union, soon up to 27% of households will be mobile only, and for many of those households cost will be the reason.

Prepay mobile and text are an amazing, inexpensive enabler of communications, and they’re easy to understand. Text messages and minutes have a cost. Sometimes in-network minutes cost less, but there’s a finite set of variables at play. On a monthly basis, prepay is usually cheaper than keeping up payments on a fixed line – and unlike fixed lines, prepay mobiles still receive calls and texts for months when you’re out of credit.

Prepay mobile data is an entirely different beast. It is far more expensive than fixed-line data, and comes in far smaller allocations. It’s allocated in bytes, not minutes, and it can be hard even for technical users to understand how bytes are getting spent. A simple mistake like allowing Windows Update to run over mobile data could see a data cap meant to last a month gone in minutes.

It’s true that mobile data is more expensive to provide than fixed-line data, though in New Zealand some of this expense comes from government policies around the sale of radio spectrum and carriers’ abilities to build radio towers. Other factors include New Zealand’s low population density. The end result is that prepay mobile data on Telecom’s and Vodafone’s national networks can be 50x more expensive than data on their fixed line networks.

It’s also true that the amount of mobile data required to perform most day to day tasks on the Internet is vanishingly small, and using the mobile web can be surprisingly inexpensive. For less than the standard cost of a prepay text message, you could check your balance on a mobile-optimised online banking website, download a Charles Dickens novel from Project Gutenberg, and have an entire conversation via Facebook Messenger.

The cost of optimised mobile data is so small that when Amazon sell a 3G-enabled Kindle, they include free 3G data for life, worldwide. Take your Kindle anywhere and the cost of browsing their store or downloading a new book is zero. Want to Tweet that you’ve finished a book? That’s free too. Similarly, Facebook have launched a product in many countries called “Facebook Zero”, where all mobile data traffic associated with viewing and posting status updates (but not watching movies) on a special Facebook page is free.

Even though only a small amount of data is required for many important Internet tasks, if you’ve blown your data cap watching a YouTube video or listening to streaming music, you’re out of luck until you can afford to top up your account again – and if your child needs the Internet for schoolwork, they’re out of luck too. Such situations result in the worst kind of social exclusion, and only serve to widen the digital divide.

This is a solvable problem, and a solution can be had without new legislation or regulation of the telecommunications industry. Amazon and Kindle have shown us that there is a market mechanism for providing free mobile data to end users: Sending Party Pays.

The idea of Sending Party Pays (SPP) has been around since the days of the Penny Post, and was the standard medium of business communication for the hundreds of years before the advent of the Internet. It allows businesses and government to directly pay carriers to communicate with customers or constituents who might not otherwise have the desire or means to pay for such communications. It further provides an incentive for senders to be concise and efficient with communications, both in terms of quality and quantity. It’s a proven model that needs to be extended into the digital age.

I call on government to commit to offering mobile-optimised versions of all government, social services, National Library, and Network4Learning resources in a Sending Party Pays arrangement with mobile carriers. Every New Zealander with a working SIM card should be able to access such services no matter their financial situations. Given the low transactional costs possible with 3G data, for a few million dollars a year we could make sure no one is excluded from a digital revolution that should be raising up all members of our society.

There will always be a place for requester pays content. In the present business model, all mobile web content is the equivalent of an 0900 call on a landline. When it comes to socially beneficially information, that’s not right. Uploading party pictures or watching the latest viral video shouldn’t be free, but everyone should be able to access education, health care, social services, and government resources for free, and as a society we should be providing this access in the easiest, most efficient manner possible.

If you want to discuss the policies, commercial mechanics, or the technologies that would enable a broad move to the provision of Sending Party Pays 3G data, come to NetHui in Wellington this July and let’s get on with ensuring Internet services are accessible for all New Zealanders.

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.

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.