Telecom Informer


by The Prophet

Hello, and greetings from the Central Office!

Or at least what passes for a Central Office in my life these days.  It has been a whirlwind few months in Rotterdam, and I am still neck-deep in management training.  I am preparing for a future life as a silver-haired executive, and it's a huge change of pace.  Rather than spending my evenings doing "service monitoring" and reading Line, WhatsApp, and Skype conversations (it's really amazing what deep packet inspection equipment can do these days), I'm buried in Harvard Business School case studies.  "Soap or Beauty Bar?" was the case from yesterday, and that's another six hours of my life that I will never get back.  It's amazing just how uninteresting your life can become if you really set your mind to it.

Weather in the Netherlands is pretty awful, the food isn't very exciting (a typical dish is called stamppot, in which you mash vegetables and mystery meat together with potatoes), and it's an expensive country to visit.  The moment I had a week free, I hopped on a plane and headed to Thailand.  Malaysia Airlines flies to Phuket via Kuala Lumpur, so I managed to squeeze three countries into this trip (Thailand, Myanmar, and Malaysia).  Although Malaysia bills itself as a high tech center, Internet service is censored and I was surprised to find that it is relatively slow (tested from numerous locations over multiple networks in Kuala Lumpur).  The service is considerably faster in Thailand, but I was surprised to find a censorship firewall in use there as well.  Want to know about the King of Thailand?  You'll be politely reminded that Thailand, while friendly, is not a free country.  And in Myanmar?  Locals in the village I visited near Ranong use wireless Internet access from Thailand.  You can get Internet access from the local authorities, but it's slow, censored, and operates via a USB modem.  "USB modem?" I asked, and so it was that I saw my first-ever CDMA450 device.

Although CDMA450 has either been deployed or is in testing throughout 62 countries worldwide, I'd never actually come in contact with any CDMA450 equipment.  While China Telecom theoretically has a nationwide CDMA450 deployment, the equipment isn't normally carried or sold in cities or even in the very rural areas in China that I have visited.  I was never able to get a clear answer on where to buy the equipment or how to obtain the service, although I'm sure the deployment must exist because two Chinese companies (Huawei and ZTE) manufacture CDMA450 handsets and base stations.

CDMA450 operates much like any other CDMA deployment using the Qualcomm CDMA2000 technology, but it operates in the 450 MHz spectrum, which is a much lower frequency than normally deployed.  Typical CDMA2000 deployments (like those operated by Verizon, Sprint, and US Cellular) are in the 800 MHz, 900 MHz, 1800 MHz, and 1900 MHz bands.  CDMA450 reuses spectrum that was previously deployed in Russia, Africa, Southeast Asia, Latin America, and Eastern Europe for a legacy analog cellular technology called NMT, and was designed as a drop-in replacement for this obsolete technology.  This is similar to the United States, where CDMA systems were designed as a drop-in replacement for the AMPS analog cellular technology.  The technology performs very well in the field, and each CDMA450 cell can cover a much larger distance than at 800 MHz or 1900 MHz.  For example, a single CDMA450 cell can cover a maximum radius of approximately 50 km, whereas a single CDMA1900 cell can cover a maximum radius of approximately 13 km.  In relative terms, you would need nearly 14 CDMA1900 cells to provide the same coverage area that a single CDMA450 cell can provide.

The first deployment of CDMA450 technology was in Romania, shortly followed by a deployment in Russia.  Today, CDMA450 is used in dozens of countries to provide coverage across vast distances with relatively sparse population.  It is possible to deploy CDMA450 in more populated areas as well by deploying more cells, and having each transmit at lower power.  However, CDMA450 is generally used to provide coverage in areas where other communications options aren't available.

Given the rural nature of CDMA450 coverage and the relatively lesser developed markets in which it is deployed, there are relatively few devices available.  While base stations are available from all major telecom equipment manufacturers worldwide, the majority of deployments are Huawei and ZTE (there are also a few Ericsson and Lucent deployments).  Most popular CDMA450 handsets are sold by a few smaller Chinese manufacturers.  The design of CDMA450 handsets differs substantially from other CDMA handsets because a larger antenna is required (and an external antenna is best).  Although CDMA450 handsets come from a limited number of manufacturers in a relatively smaller number of models, they do not entirely lack for features.  One popular CDMA450 phone, the Qlink C820, runs the Android 2.3.4 operating system in a variety of languages.  You will not, however, find the latest phones from popular manufacturers operating on CDMA450, so the iPhone will probably not be coming to the steppes of Siberia any time soon.

Another type of popular CDMA450 handset is designed for a fixed location and has a very large antenna.  These are called "wireless local loop" handsets, and look similar to a conventional telephone.  These handsets are used in very remote locations with a weak signal and are typically paired with a Yagi antenna which can be mounted on a pole or rooftop.

While it is possible to deploy CDMA450 in a "data only" configuration, and some carriers have chosen to do so, voice is still considered the "killer application."  The majority of deployments offer 1xRTT, but this is only optimal for voice and text services.  Data services are available with 1xRTT, but operate at a maximum speed of 144 kbps.  1xEV-DO, depending on the revision deployed (DO, DOrA, or DOrB) offers varyingly faster speeds.  With the EV-DO Revision A (DOrA) flavor, the most popular, the theoretical maximum download speed is 3.1 Mbps with a theoretical maximum upload speed of 1.8 Mbps.  In practice, speeds are slower, but this is still enough for basic web browsing, email, and instant messaging services.  In remote areas where Internet service may not be practical to provide via any other means, the performance can be considered acceptable.

Given the rural nature of CDMA450 deployments, backhaul to the rest of the telephone system may not be easily possible.  One vendor, AirWalk, has developed an integrated solution intended for extremely remote areas that can be easily interfaced to satellite backhaul.  In one such deployment, a base station and satellite uplink was placed on a mountaintop and was able to provide coverage to the entire valley below.  It's important to note that the speed of Internet connectivity is limited by both the performance of a 1xEV-DO session and the available Internet backhaul from the base station, so obviously Internet speeds will not be fast in such a deployment.  Similarly, voice service is limited by the number of available voice channels, which are typically trunked via VoIP.  All of this is configurable at the base station so engineers can provide the best user experience based on the trade-offs in play.

The U.S., Canada, Australia, and Western Europe (excluding small-scale trial deployments) are conspicuously absent from CDMA450 deployments.  In the US, the 450-470 MHz frequencies that are considered optimal are already occupied, including by amateur radio users.  Given the complexity in reassigning these frequencies and the relatively high availability of traditional telephone services - even in the most rural parts of these regions - means that future deployment of CDMA450 is unlikely there.  However, in the developing world, CDMA450 will help to serve areas that may not ever be serviced by traditional "wired" telephone service.  While this technology will not fully serve to bridge the "digital divide," I believe it can help to enable telephone service in places where it was not previously available.  While Google has stated ambitious plans to deploy Wi-Fi from dirigibles, CDMA450 is available now and works well today.

And with that, it's time to bring this issue of the Telecom Informer to a close.

The next few months will bring another two continents, so if you'd like to see me this year, try to catch me at DEFCON 21 in Las Vegas.

Stay safe this summer, don't forget to send in your favorite payphone pictures, attend your local 2600 meeting, and never stop exploring!

References - CDMA Working Group – CDMA450 World Update (23 Feb 2011), CDMA450 Deployments Reference

Luo Huifang, ZTE: CDMA450: Lower TCO Enabling Greater Profits

Netevschi, Surana, Du, Patra, Brewer and Stan: Potential of CDMA450 for Rural Network Connectivity

AirWalk Communications: AirWalk CDMA 450 MHz Rural Solutions (April, 2009)