ALL ABOUT CDMA - AUSTRALIA's NEW DIGITAL MOBILE PHONE SYSTEM
By Boyd Munro, President of APUMP (Association for the Protection of Users of Mobile Phones)
CDMA is a second-generation digital mobile phone system. It is completely incompatible with Australia's existing GSM digital system - and much better than it.
All CDMA phones can work from CDMA base stations or analogue base stations. But they cannot work with Australia's existing GSM digital base stations. And GSM digital phones can only work on GSM digital base stations. GSM digital is an incompatible self-contained world unto itself.
On 9th July 1998 the Deputy Prime Minister, Mr. Tim Fischer, announced that Telstra plans to build a nationwide CDMA network. Here is an excerpt from his Press Release:
"This decision means that every area of Australia which currently receives mobile phone coverage from the Telstra analogue AMPS network will continue to receive the same coverage when the network is upgraded …"
Study that promise carefully, because it is the one that counts. The government is accountable to us, whereas Telstra is not. Telstra might change its mind for commercial reasons because it is accountable to its shareholders, not its customers. But the Government is accountable to its electors (that is, to us) - and under the legislation the government has the power to direct Telstra as to what it is to do.
Click here
for the initial media releases and comments about the CDMA announcement.ABOUT APUMP - AND A DISCLAIMER
APUMP is a member-funded organisation. Our only aim is to ensure that our members get the very best possible mobile phone service at an affordable price. We do not sell phones or phone services. We are not secretly paid to represent anyone.
What appears below represents APUMP's true belief or opinion. Readers should be aware that other people hold different beliefs or opinions. At the bottom of this piece we provide the internet addresses of the major organisations which have differing beliefs and opinions. We invite you to refer to their websites and make up your own mind!
PHONE AND NETWORK COMPATIBILITY
WILL AN EXISTING AUSTRALIAN GSM DIGITAL PHONE WORK ON THE NEW CDMA DIGITAL NETWORK?
No. GSM is incompatible with all other systems.
WILL A NEW CDMA PHONE WORK ON THE EXISTING AUSTRALIAN GSM DIGITAL NETWORK?
No. GSM is incompatible with all other systems.
WILL A NEW CDMA PHONE WORK ON THE EXISTING AUSTRALIAN ANALOGUE NETWORK?
Yes.
WILL AN EXISTING AMPS ANALOGUE PHONE WORK ON THE NEW AUSTRALIAN CDMA DIGITAL NETWORK?
No, you will need a new CDMA phone to use the new CDMA network. But that CDMA digital phone will work as an analogue phone on the analogue network.
HOW IS THE VOICE QUALITY OF CDMA?
I bought my first CDMA phone in September 1997 in Houston, Texas. Half an hour later I called my wife from a taxi en route to the airport. I told her I was speaking on a new CDMA mobile phone. She said "I can't believe you're on a mobile, your voice is so clear and natural". The voice quality of CDMA phones is very good.
CAN I BUY A CDMA PHONE IN AUSTRALIA YET?
As far as APUMP is aware, no dealer is yet stocking them. If you are a dealer, and you have CDMA phones in stock, please contact APUMP and we'll list your details here. There is no reason why CDMA phones should not already be available in Australia because they can work on the existing analogue network until the CDMA network becomes operational.
CAN I BUY A CDMA PHONE OVERSEAS, AND USE IT IN AUSTRALIA NOW?
Yes, with great care. I use the CDMA phone I bought in Houston in September 1997 as an analogue phone in Australia, and it will work as a CDMA digital phone as soon as Telstra's CDMA network is commissioned. But just as many overseas GSM phones won't work in Australia, there are many overseas CDMA phones which won't work on the Australian analogue network. There are an enormous number of different variations of mobile phone standards.
TECHNICAL INFORMATION ABOUT CDMA
All mobile phones are radios. They transmit your voice to a base station (or Tower) by radio. The base station then converts your voice for transmission over the normal phone network.
HOW DOES CDMA DIGITAL DIFFER FROM GSM DIGITAL?
CDMA has almost no similarity to GSM digital. GSM digital is a pulsed system (the technical name for this is Time Division Multiple Access or TDMA). The GSM digital handset records your voice, then converts that recording to digital form. It transmits the speech package in a very short burst (in my terms, GSM phones work to a pattern of one beat on, 7 beats off). The pulsed nature of GSM has caused most of its problems, from short range to hearing aid incompatibility.
CDMA or Code Division Multiple Access works quite differently. CDMA is digital but it is not pulsed. Many phones share the same radio frequency but instead of taking turns they all transmit at once. Almost incredibly, the base station can sort out which transmission comes from which phone, and then turn it back into voice for transmission on the phone network. Although each phone transmits on the same frequency, its transmissions are encoded by a Walsh Code, and the base station uses the underlying Walsh Code to distinguish between all the transmissions. I am the first to admit that if someone had described the principles of CDMA to me before it was a working commercial system, I would have said "Great stuff for the Lab, well done. But it will never work in practice.". However it does work in practice, and it works damn well.
A good analogy for the way CDMA works is the multi-lingual cocktail party. You put 50 couples in a crowded room, each couple speaking a different language. Even though the overall noise level is very high, an English-speaking person can still understand the conversation of the English-speaking couple. In this case the underlying language is like the underlying Walsh Code - it's the mechanism which is used to distinguish between the various participants.
QUESTION MARKS OVER CDMA
There are some question marks over CDMA in the Australian environment. The major question concerns base station range. There are many analogue base stations which achieve great range (well over 100km) in Australia. I have doubts about whether CDMA base stations will perform as well. Another important question concerns data transmission capability. I own a Sony/Qualcomm CDMA digital phone, and have a PCMCIA data card which allows the phone to transmit data. The only problem is, the first step in performing data transmission is to put the phone in analogue mode! The Nokia 2180 CDMA phone is the same. This means that is the analogue network is closed down, these phones won't be able to do data transmission. Of course this problem "will shortly be corrected" but APUMP does not believe any high-tech promises which aren't supported by seeing, touching, feeling! Qualcomm demonstrated CDMA data transmission at the PCS-97 show in Dallas in September 1997, but as far as we know the humble user still can't transmit data to a CDMA base station.
APUMP has been unable to get definitive answers on the question of the range of CDMA.
On 6th August 1988 - an e-mail from Jim Takach of CDG says "CDMA can certainly achieve the 60 mile AMPS range you mentioned in your e-mail. Deriving a maximum number depends on parameters such as total antenna height, # of subscribers and their usage patterns, transmit power, and interference."This sounded a little better, so APUMP responded quoting the latitude and longitude of
the AMPS analogue tower on Mount Kaputar in northern NSW, and the latitude and longitude
of a place near Collarenebri where that tower provides satisfactory reception. Here is
Jim's response
"Regarding your last e-mail, given the antenna height (and other technical
assumptions), the CDMA Forward link range is 108 miles, reverse link range is 98 miles.
Given similar assumptions, AMPS is about the same."
That still isn't the kind of answer I can understand.
However we users are well-protected by some government promises.
The meaning of that is very clear. Until it is demonstrated that CDMA digital will provide the same coverage as a given AMPS analogue base station, that base station will not be "upgraded" (i.e. closed down).
"The advice from Senator Richard Alston's office is that the AMPS system will start to be replaced by CDMA within months with no break in service.
"The new CDMA system will completely replace the existing analogue AMPS system, in both city and country, and will provide the same coverage as AMPS."
Again, the meaning is clear. If CDMA does not provide the same coverage as AMPS, we keep AMPS so there is no break in service.
Rural users will lose out if they have to pay for a new phone or have to pay increased call charges or monthly charges. This promise, therefore, means that rural users will receive CDMA phones free of charge in exchange for their analogue handsets. Note that this promise is limited to rural users, that it limited to analogue users (because no digital user will lose out because of the analogue phaseout), and above all that it is limited to users which stresses the great importance of keeping an analogue subscription until the bitter end!
Again, that's clear.
These promises are clear enough. But we all know that politics is politics. Promises are not always kept, and governments change. What's more, whilst these promises are good news for us, they are very bad news for Vodafone (not Vodaphone) and Optus, companies which had expected to make enormous gains at our expense from the forced closure of the analogue network. Vodafone and Optus are accustomed to getting everything they want from Australia's governments of both flavours. They will fight this one to the very last.
At this moment (August 1998) the Opposition has made no commitment about what it will do about mobile phone coverage should it win government at the next election. APUMP is working to get a satisfactory commitment from Labor, but until such a commitment is obtained we should be aware that Labor may very well prevent Telstra setting up a nationwide network should it win government. After all, it was Labor which originally made the decision to force Telstra to close down its analogue network so that Optus and Vodafone would "have a better chance"! At that time, Labor put the interests of Vodafone and Optus ahead of those of Australia's analogue phone users and of Telstra. See what I mean about Vodafone and Optus being very effective lobbyists? But back in 1992, APUMP did not exist and we users did not have a watchdog. Now we have a watchdog.
TECHNOLOGY THROUGH POLITICS
If we want to enjoy the undoubted benefits of mobile phone technology in Australia, we'll have to be political about it. There's just no choice. If we as end users remain silent, the government hears only the voices of the suppliers - and the outcome will be as silly as the 1993 decision to close the analogue network!
My guess is that the end result of the CDMA announcement will be that a large part of the existing regional AMPS network remains in service. In regional areas CDMA is expensive to install and offers only one benefit by comparison with AMPS - it's much harder to intercept. Far better for Australia to spend its national resources installing more AMPS base stations to serve areas that have no mobile service than to replace perfectly good AMPS base stations with CDMA base stations.
THE NEXT STEP
Write to your federal MP asking for an assurance that CDMA really will cover every place that AMPS covers, and that no AMPS base station will be closed until it has been demonstrated that CDMA coverage is available in every square metre served by that AMPS base station. If you are in regional Australia, ask whether the government's assurance that no-one in regional Australia will lose out because of the AMPS closure still stands. Also ask whether this means that analogue users in regional Australia will receive CDMA service at the same price as the existing AMPS service and will receive a free CDMA phone. You should send copies of your letter to the candidates who will oppose your Federal MP at the next election.
When you receive a reply, be sure to mail or fax a copy of your letter and the reply to APUMP. By acting as a central clearing house we are able to collate the various assurances given (as we did above) and if necessary apply broad grass-roots pressure to ensure that promises are actually delivered.
FURTHER INFORMATION
GENERAL
AUSTRALIAN GOVERNMENT
COMMENTATORS
COMMERCIAL ORGANISATIONS WITH AN APPARENT PRO-CDMA VESTED INTEREST
COMMERCIAL ORGANISATIONS WITH AN APPARENT ANTI-CDMA VESTED INTEREST
COMMERCIAL ORGANISATIONS WHICH ARE APPARENTLY TECHNOLOGY-NEUTRAL
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