Monday, April 2, 2012


Packet One Networks in Malaysia, one of the pioneer WiMAX operators, says it intends to migrate to LTE TDD by the year-end, reports Light Reading.

According to The Star newspaper, P1 currently has more than 280,000 users, but now intends to migrate to LTE TDD once technologies are more mature.

Light Reading observes that P-1′s investor partner, SK Telecom, is also testing LTE TDD with China Mobile. China and India are big proponents of the spectrum-efficient TD-LTE approach which doesn’t require paired channels. Their testing found TD-LTE performance delivered average cell throughput (10MHz system bandwidth) of 14.6Mbps downstream (spectral efficiency: 2.69bps/Hz), while uplink average cell throughput is 6.2Mbps (spectral efficiency: 1.55bps/Hz), both meeting NGMN (Next Generation Mobile Networks) requirements.

Other WiMAX operators, including Yota in Russia plan to migrate to LTE, while broadband license-holders in India are also opting for LTE TDD deployments instead of WiMax.

NTT Docomo launched commercial LTE service in Japan last December. Docomo’s LTE service will cover Tokyo, parts of Osaka, Nagoya and a handful of other areas near these cities. It is initially limited to only major cities. The Japanese mobile operator was the world’s first to launch a 3G network, back in 2001. TeliaSonera in Sweden, was the world’s first to launch LTE, in December of 2009.

India’s top mobile firm, Bharti Airtel, No. 2 Reliance Communications, Vodafone, Tata Teleservices, and Idea Cellular spent a combined $23 billion for licenses in recent 3G and 4G spectrum auctions (auction results) in the world’s fastest-growing cellular market. Qualcomm won 2.3GHz spectrum (20 MHz) in four telecom circles of India in the recently held BWA spectrum auctions and plans to go with TD-LTE.

TD-LTE gained credence once China Mobile, the world’s largest wireless operator, said it planned to deploy TD-LTE across its network. China currently has over 720 million mobile cellular subscribers, more than twice as many as the United States.

China Mobile, the largest mobile operator in the world , is reportedly planning metro TD-LTE trials in up to six cities; Beijing, Shanghai, Guangzhou, Nanjing, Shenzhen and Xiamen. Various reports suggest the world’s largest operator has deployed 3,000 base stations and is waiting for approval by the Ministry of Industry and Information Technology (MIIT).

It looks like a wrap. No party at the WiMAX Forum is likely.

Proponents say WiMAX delivers real benefits in cost/effectiveness. It’s a greenfield solution, free from carrier control, spectrum restrictions and onerous patent overhead. My WiMAX service from Clearwire in Portland over the past year has been great. It’s not perfect, but it provides me with my sole source of broadband — both at home and mobile — for only $40/month. It’s a pretty good deal.

WiMAX Forum New President

WiMAX Forum announced that February 1st, 2012, Ronald Resnick will retire from his role as the President of the WiMAX Forum.

Mr. Resnick has been a valued part of the WiMAX leadership for the past eight years,” said Dr. Mohammad Shakouri, Interim Chairperson of the WiMAX Forum. “The WiMAX Forum would like to thank Mr. Resnick for building a strong foundation for this organization, which will continue its work in standardizing and certifying technology to bring broadband to underserved markets across the world. We all wish Mr. Resnick the best of luck in his future endeavors.”

The WiMAX Forum also announced that Declan Byrne has been unanimously elected as Acting President of the WiMAX Forum. Declan Byrne joined the WiMAX Forum in 2010 as the Senior Director of Marketing. Prior to joining the WiMAX Forum, Byrne worked for Airspan as Chief Marketing Officer.

The WiMAX Forum performs a similar function as the WiFi Alliance; it promotes the use of the technology and tests compatibility. WiMAX Forum-certified gear is tested to for compatibility to the standard, so for example, a Samsung WiMAX basestation will work with a Huawei WiMAX client.

The IEEE develops communications standards. They include IEEE 802.16 (WiMAX), which the WiMAX Forum promotes and enforces, and IEEE 802.11 (WiFi), which the WiFi Alliance promotes and enforces.

Last week the International Telecommunication Union (ITU) approved the “WirelessMAN-Advanced” as part of IMT-Advanced world-wide 4G technology standard. WirelessMAN-Advanced is based on the IEEE 802.16m. The WiMAX Forum calls it WiMax 2.0 (pdf)

Key features of WiMAX 2.0 include:

  • Radio specification for FDD and TDD
  • Support of IMT-A frequency bands
  • At least 2 times the average data throughput of current Release 1.5 in similar spectrum
  • Advanced interference management methods to support true reuse 1 deployments as compared to current reuse 3 deployments
  • Round trip access latency is reduced to less than 10-20 ms levels which will allow more demanding services like online gaming etc.
  • Support for self organizing networks
  • Support for femtocells
  • Support of relay stations
  • Multicarrier aggregation up to 100 MHz
  • Co-existence of 16e and 16m base stations and backward compatibility
  • Over 70 VoIP calls per MHz

Analysts say there is perhaps a 75% technology overlap between the two dominant broadband wireless standards, LTE and WiMAX. Each has their own strengths and weaknesses.

Advantages of WiMAX 2 over LTE Advanced:

  • Simple, fast and cheap
  • Compatible with WiMax 1.0 and 1.5
  • Can use licensed or unlicensed spectrum
  • Fewer patent issues
  • Less telco overhead and control

Dailywireless depends 100% on my single WiMax connection. It’s been (mostly) reliable since 2009, and costs me only $40/month. I get truly unlimited service, use my WiMAX dongle for both my laptop and my desktop, and watch Netflix at night.

You can’t do that on LTE. You’d go broke. It’s that simple.

WiMax combines the simplicity and speed of Wi-Fi with the mobility of cellular. It works. WiMAX lost a year or two in development and LTE was put on a fast track. The result; WiMAX got only a one year advantage, while Telcos jumped on duplex FD-LTE. India and China moved the momentum to TD-LTE.

But WiMAX 2.0 is simple, fast and license-free. It’s going to be hard to kill.

Nokia Sells WiMAX Unit to NewNet

A week after announcing plans to cut 17,000 jobs as part of a restructuring, Nokia Siemens Networks said today that it was selling off the WiMAX assets it acquired from Motorola Solutions to NewNet, a privately held company with headquarters in Connecticut. NSN bought Motorola’s networking business in August for $1.2 billion, which included Motorola Solutions’ CDMA assets, reports RCR Wireless.

The NewNet deal, which is expected to close by the end of the year, includes all related assets, active customer and supplier contracts, and about 300 NSN employees. Many of the employees are based in Chicago and Hangzhou, China. Financial terms of the deal were not released.

Motorola, which had revenues of $22 billion last year, split into two separate companies; Motorola Mobility and Motorola Solutions, a land mobile radio and services company for enterprise and government customers.

Motorola’s WiMAX unit, Samsung’s WiMAX unit and Huawei were all on Clearwire’s preferred vendor list. Clearwire cities like Portland, Oregon, use WiMax gear from Motorola, Nokia Siemens, now NewNet.

Nokia Siemens Networks’ plan to solely focus on the mobile broadband market, using mostly LTE-based technologies. NSN recently was included in an announced trial of LTE services across London with Telefonica’s O2, as well as garnering a network upgrade contract in Finland from TeliaSonera.

WiMAX to TD-LTE: Changing

Southeast Asia’s first 4G operator, Packet One Networks, launched its WiMAX service in Malaysia in August 2008 and is now preparing to transition to LTE.

Packet One, a wireless ISP, expects to begin a transition to a full LTE network in 2013. Packet One, a subsidiary of Greenpacket, and a leading developer of 4G systems, is testing a dual-mode 4G WiMAX/LTE solution from Sequans for dual-mode WiMAX/LTE, and hopes to launch a complete ecosystem of 4G networking solutions and devices by the end of 2011.

Gemtek’s new TD-LTE indoor CPE is based on Sequans’ SQN3000 series LTE chips, which support up to 100 Mbps throughput and 20 MHz channels. “We expect the new CPE to begin commercial deployment in the third quarter of 2011,” said James Ting, GM, Broadband Wireless Business Unit, Gemtek.

“As Southeast Asia’s leading 4G operator, first for WiMAX and now for dual-mode WiMAX and LTE, P1 has three years of experience operating an end-to-end 4G network,” said Michael Lai, P1 CEO. Packet One uses 30MHZ of its 2.3GHz spectrum for WIMAX, but plans to re-farm 20MHz of this for LTE leaving 10MHz for its legacy WIMAX subscribers. This will happen in a gradual process over the next two years, Lai says.

Greenpacket is testing Sequans’ system-on-chip technology to develop LTE reference designs, including a dual-mode WiMAX/LTE reference design for operator customers primarily in Asia, CALA and Middle East, according to James Wang, Senior Vice President of at Greenpacket. “We intend to offer our solutions to early adopters of LTE such as P1 in support of its LTE/WiMAX coexistence strategy.”

Sequans’ recently announced their 4Sight program, to help mobile operators transition smoothly and cost-effectively from WiMAX to LTE and enable harmonious WiMAX/LTE coexistence.

P1 was the first large-scale commercial 4G WiMAX deployment in Southeast Asia, and the first large-scale deployment of an 802.16e 2.3GHz WiMAX network outside Korea. P1 is one of nine Malaysian companies allocated 2.6GHz spectrum. In addition to Sequans, Packet One also announced TD-LTE collaborations with China Mobile, Qualcomm & ZTE.

Packet One has a technology cooperation agreement with China Mobile to spearhead Time Division LTE (TD-LTE) in Malaysia and South-East Asia.

“The economies of scale brought by China Mobile, with its subscriber base of over 600 million will see rapid development of the entire TD-LTE ecosystem,” said P1 chief executive officer Michael Lai at the signing ceremony this week. China Mobile is among the first operators to have adopted the TD-LTE technology and it is one of the founders of the global TD-LTE Initiative (GTI).

Clearwire-USA is one of the 20 members of the Global TD-LTE Initiative. Others include Aero2-Poland, Belltell-Philippines, Bharti Airtel-India, China Mobile-China, Datame-Finland, E-Plus – Germany, FarEastone-Taiwan, FITEL-Taiwan, Korea Telecom-Korea, Omantel-Oman, Nextwave-USA, P1-Malaysia, Smoltelecom-Russia, SoftBank-Japan, Tatung Infocomm-Taiwan, Vividwireless-Australia, Vodafone-UK, Voentelecom-Russia and Woosh-New Zealand.

Most WiMAX operators will migrate to LTE, but the pace and modalities of the shift will vary greatly depending on geography, service focus, spectrum availability, and funding, says Monica Paolini (PDF).

ZTE, a global Chinese provider of telecommunications equipment, has completed an interoperability test between TD-LTE terminals and GSM/UMTS/CDMA EV-DO networks, proving their TD-LTE devices can work seamlessly with existing networks. ZTE has deployed TD-LTE trials and commercial networks for 25 leading global operators in 15 countries.

Operators going with TD-LTE include China Mobile, Vivid Wireless in Australia, Yota, in Russia, Global Mobile in Taiwan and Packet One in Malaysia. India will also be a TD-LTE country.

Yota announced that it will cover the next 15 cities on its roll-out list with TD=LTE instead of WiMAX. It will also cover existing markets in Moscow and St. Petersburg with LTE by the end of 2011. Yota will spend $100 million to roll-out LTE in five Russian cities this year, with total investment estimated at up to $2 billion.

“The biggest concern facing many operators now is the squeeze on available spectrum,” says ABI research analyst Fei Feng Seet. “Regulators in certain countries have not yet announced any plans for LTE spectrum allocation.” Countries such as Taiwan will not be ready for such LTE spectrum auctions any time soon, because the 700MHz and 2.6GHz spectrum bands, the most suitable for LTE, are still occupied.

The fix is in. It’s circumstantial evidence that Clearwire and Sprint may go with TD-LTE. Paired spectrum at 2.6 GHz would be a real spectrum hog when moving to next generation LTE-Advanced with 20MHz x 2 channels (using FD-LTE). LTE Advanced includes support for relay node which extends coverage by using the LTE channel for selfbackhaul. Handy for satphone frequencies, too.

Grid Net uses the WiMax protocol, in partnership with Sprint, but some players, like SmartSynch use public cellular networks through partnerships with players like AT&T. Other smart grid companies like Trilliant and Silver Spring, use private mesh networks.

Clearwire’s “LTE 2X” trials in Phoenix use paired, 20×20 MHz blocks, twice the size Verizon’s LTE. But the economies of scale developing around TD-LTE may be compelling for Sprint.

Wednesday, July 20, 2011


Do mobile phones cause cancer? The debate has been raging for years, and we’ve covered it several times on this blog.

Today, the International Agency for Research into Cancer (IARC), which is part of the World Health Organisation – had their say. Over the last week, they convened a panel of 31 experts to look at the available evidence. Their verdict: “radiofrequency electromagnetic fields” – the sort given off by mobile phones – belong to “Group 2B”, which means that they “possibly” cause cancer in humans.

What does that mean?

It means that there is some evidence linking mobile phones to cancer, but it is too weak to make any strong conclusions. Specifically, IARC’s panel said that the evidence that mobile phones pose a health risk was “limited” for two types of brain tumours – glioma and acoustic neuroma – and “inadequate” when it comes to other types of cancer.

The Chairman of the group, Dr Jonathan Samet, said, “The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk.”

IARC classifies different things according to whether they are likely to cause cancer, from tobacco to viruses to certain jobs. They are the gold standard for this sort of thing. They have five possible categories of risk:

Group 1 is the highest, reserved for things like smoking, asbestos, alcohol and so on. It means that there’s extremely strong evidence that the thing in question causes cancer.

Group 2A includes things that are “probably carcinogenic to humans”. Here, the evidence is “limited” in humans, but “sufficient” from animal studies.

Group 2B – this is the one that mobile phones now fall under – means something is “possibly carcinogenic to humans”. It means there is “limited evidence” that something causes cancer in people, and even the evidence from animal studies is “less than sufficient”. Group 2B means that there is some evidence for a risk but it’s not that convincing. This group ends up being a bit of a catch-all category, and includes everything from carpentry to chloroform.

Group 3 means that something is “not classifiable as to its carcinogencity to humans”. This means that the evidence is “inadequate in humans or “inadequate or limited” in animals. Usually, there just haven’t been enough studies to say either way.

Group 4 means something probably doesn’t cause cancer in humans. So far, there is only one chemical – caprolactam – in this group. People jokingly take this to mean that everything causes cancer but it simply reflects the fact that IARC focuses its attention on things that could potentially pose a health risk.

Where does the evidence come from?

Even though this topic gets a lot of press attention, there have been a relatively small number of studies on mobile phones and cancer. Most of these are “case-control studies” – they compare people who already have cancer (cases) with healthy people (controls), and ask them about how they used their phones in the past. These studies include the InterPhone study, an international collaboration of scientists from 13 countries, and work by Lennart Hardell’s group at University Hospital, Orebro.

So far, only one Danish study has actually followed a group of healthy people (around 420,000 of them) to see if their use of mobile phones affected their future risk of cancer.

What does the evidence say?

A smaller number of publications, mostly from the Hardell group, have found associations between mobile phones and brain cancer risk. But the majority of papers, including those from InterPhone and the Danish study, have found that mobile phone use does not increase the risk of brain cancer, or any other type of cancer, for at least 10 years of use.

To give you an idea of the evidence to date, here are two images that represent the studies on mobile phones and glioma brain cancers up to 2009 (taken from this paper). The top one shows the effect of short-term use (less than 5 years), and the bottom one deals with long-term use (more than 5 years). Each dot shows the result from a single study. If it’s on the horizontal line, there is no effect. If it’s above or below the line, this suggests that phones might increase or reduce the risk of cancer respectively.

The bars above and below the dot are important – they represent the “confidence interval”, which indicates how reliable the result is. If the bars cross the horizontal line, this means the result is not statistically significant. It could have been down to chance, or bias. As you can see, only one study out of 14 found the mobile phones significantly affect the risk of cancer.

The dot that’s second from the right (labelled “pooled estimate”) represents the combined results from all the studies. Again, you can see that it’s pretty much sitting on the line, which suggests that mobile phones do not affect the risk of cancer.

click to enlarge

Some studies have suggested that people have a higher risk of brain cancer specifically on the side of the head that they say they hold their phones to. However, many of these studies have also reported either no overall increased risk of cancer, or a lower risk of tumours on the other side of the head.

Scientists disagree as to whether this “side-of-head effect” is real. If phones were really increasing the risk of brain cancer on one side of the head, you would still expect to see this reflected in the overall result. Alternatively, the result could be due to bias, because people inaccurately remembered how they used their phones (see below). Nor is it clear if people actually hold their phones consistently to one side of their heads.

What are the weaknesses of these studies?

All the existing studies suffer from similar problems.

  • Changing technology. Mobile phone technology has also changed considerably over the last decades and it is not clear if studies based on use of old models will apply to modern ones.
  • Assessment problems. There still are no clear ways of assessing someone’s actual exposure to mobile phone radiation. Instead, studies use questionnaires to work out whether and how people use mobile phones. These questionnaires rely on people accurately remembering their past mobile phone use years or decades ago. In some of the Hardell studies, a third of patients received help from relatives in completing the questionnaires (compared to just one in ten controls). In one case, the next-of-kin of deceased patients estimated how often their loved ones used their phones.
  • Recall bias. It’s not clear if the replies to these questionnaires are accurate – a problem known as “recall bias”. Answers might be biased because people have heard about mobiles and brain cancer in the media, because brain cancer can distort memory, or simply because people misremember things that happened a long time ago.

The individual studies have drawn more specific criticisms.

The Danish study relied on subscriber records instead of questionnaires. However, there are concerns that subscribers aren’t always the ones who use the phones, and that this method excludes corporate users, who could use their phones heavily.

For example, the InterPhone study has been criticized for using unrealistic definition of “regular users” and having low response rates to its questionnaires. The authors have also disagreed as to how their results should be interpreted.

The Hardell group has been criticised for publishing the same data in multiple papers, inconsistently reporting data such as sample sizes, and having implausibly high response rates to its questionnaires.

The abstracts of their papers often highlight statistically significant links in very specific groups of people, while ignoring overall negative results. These types of analyses are difficult to interpret – if you split a sample far enough, you end up with small numbers of people in each group and greater odds of finding a positive result simply through chance.

Are there conflicts of interest?

The mobile phone industry has provided funding for the InterPhone study and the Danish study. In both cases, funds have been administered through independent, third-party organisations that are meant to act as “firewalls” to ensure the independence of the scientists. InterPhone, for example, received 19.2 million euros of funding. 5.5 million of this total came from industry sources, and was either administered through the International Union for Cancer Control, or collected via taxes and fees from government agencies.

Lennart Hardell has not received funding from industry sources but has appeared as an expert witness in litigation cases involving mobile phones.

Could mobile phones cause cancer?

This is an important question. Scientists are confident that tobacco, alcohol or asbestos can cause cancer because they can explain how these things affect the way our cells work. These explanations are called “biological mechanisms” – they play a vital role in establishing that something causes cancer.

So far no one has been able to provide a good biological mechanism for the link between mobile phones and cancer. The “how” question is an open one. The phones give off microwave radiation, but this has millions of times less energy than, say, an X-ray and is not powerful enough to damage our DNA. They mildly heat the body, but again, not enough to pose a health risk. Other suggestions have been put forward, but none are backed by consistent evidence.

Are brain cancer rates going up?

If mobile phones increase the risk of brain cancer, the rates of this disease should be skyrocketing since mobile phone use has risen dramatically over the last few decades.

But studies in the US, New Zealand, Denmark, Norway, Sweden and Finland have found no such trends. In the UK, the incidence of brain cancer has been flat for the past few decades. A recent English study concluded that “the increased use of mobile phones between 1985 and 2003 has not led to a noticeable change in the incidence of brain cancer in England between 1998 and 2007.”

Brain cancers can take many years to develop, so it is possible that trends would only start rising after more time.

What about base stations?

Base station exposures are much less likely to affect our health than phones themselves as their emissions are many times weaker and usually well below international guidelines.

Just last year, a British study (the largest of its kind) found “no association between risk of childhoodcancers and mobile phone base station exposures during pregnancy”.The authors say the results “should help to place any future reportsof cancer clusters near mobile phone base stations in a widerpublic health context.”

What should we make of the evidence?

It is understandable that people are concerned about mobile phones, especially because they are so widely used. But so far, the published studies do not show that mobile phones could increase the risk of cancer. This conclusion is backed up by the lack of a solid biological mechanism, and the fact that brain cancer rates are not going up significantly.

However, all of the studies so far have weaknesses, which make it impossible to entirely rule out a risk. Mobile phones are still a new technology and there is little evidence about effects of long-term use.

For this reason, the UK Government advises a precautionary stance. It suggests that if adults want to use a mobile phone, they can choose to minimise their exposure by keeping calls short. It also advises discouraging children under the age of 16 from making non-essential calls as well as also keeping their calls short.

And, as IARC’s working group said, there needs to be more research.

What studies are in the pipeline?

A large study called COSMOS, including researchers from the UK and four other countries, has been set up to look at the long-term effects of mobile phone use after 20-30 years. Like the Danish study, it will recruit healthy people, measure their mobile phone use and see if this affects their health in the long-term.

The MOBI-KIDS study, involving 13 countries, has been set up to look at health effects in children.