The cellular phone was imagined in 1947 by D H Ring at Bell Labs. He came up with the cell system as a way of bypassing the limited bandwidth of radio. Bell proved the concept in the mid 1970's, and a public system was available in Chicago before 1979.
The early mobile phones in Australia were analogue. These were excellent in rural areas due to their long range, but people with scanners could listen in to calls (as politicians discovered), and the available bands tended to get crowded in the cities. First generation analog was seen as an interim technology, to be withdrawn by the late 1990s by agreement with the phone companies. Many countries had analogue systems, often incompatible with each other.
Australia moved to the European GSM (Global Systems for Mobile communications) standard (a TDMA style) at the standard European 900 MHz and 1800 Mhz frequencies in April 1993. GSM was first used in Europe only on 1 July 1991, after studies commencing in 1982. GSM was widely deployed in metropolitan areas through the 1990s. GSM cells can be high powered in country areas, to provide a range of up to 20 kilometres. They can be low powered in cities to provide cells of 50 to 300 metres. This lets GSM make good use of smaller cell sizes and is a good match to city use. About 70% of worldwide cell phones us GSM.
Cells are grouped in clusters of 2, 7, 12 or 21, and repeated over the entire network area. Each cell has only a fraction of the available frequencies. This allows frequencies to be reused in non-adjacent cells. Narrow beam is used along roads outside cities to extend coverage.
Two frequency bands of 25 MHz are available, one for phone to network, the other for network to phone. Each band is divided into 200 kHz wide carriers (this is called frequency division multiple access or FDMA). Each carrier is then divided into eight equal time slots or bursts of about a half millisecond. This is called time division multiple access or TDMA.
GSM uses control channels and traffic channels. Control channels do housekeeping, like saying which frequency to use, and when a call is coming in. Traffic channels carry voice calls and data as bursts of two strings of 57 bits. Between these are training sequences to help remove interference.
Security is handled by the subscriber identity module (SIM). When the phone is first used the SIM sends an International Mobile Subscriber Identity (IMSI) number to the network, which then creates an encrypted Temporary Mobile Subscriber Identity which is sent to the phone. The phone uses this on all future calls. The network sends a random number to the phone, which uses a secret authentication number to generate another number, which is checked by the network. This number is also used to generate an encryption key to encode your conversations.
Phones also contain a International Mobile Equipment Identity (IMEI) number which can be listed by networks to check for stolen phones. Many phones will show this IMEI number if you enter *#06#
Mobile phone use has spread to around 70% of Australia's 20 million population. I believe the market for a simple phone could probably be considered fairly saturated, and unlikely to ever get above 80%.
The relatively few US companies using GSM are not able to use European frequencies due to military bands, so the USA GSM uses 1900 MHz. Thus Australian and European phones can't be used in the USA, unless specifically built as tri-band. The first generation analog AMPS is also still used in the USA, but is expected to eventually disappear. IS-136 TDMA systems are also popular in the USA.
Around September 1999, CDMA - Code Division Multiple Access (invented and promoted by Qualcomm in the USA as IS-95A/B) was also deployed in country areas in Australia. Its greater range was expected to make it a good replacement for analogue over long distances. CDMA coverage in country areas is very good, far superior to GSM, with even some relatively small towns and tourist areas covered. Coverage by 2003 exceeded 1.1 million square kilometres, about twice the GSM coverage. It is eventually expected to cover all communities with a population exceeding 300.
Phone companies are looking at moving their customers from these second generation phones to third generation (3G) or even fourth generation phones, sometimes via way of partial changes (2.5G). The phone companies appear to believe that data rather than voice will be the big selling point and profit area of future phones. They will need lots of luck. While I am sure the youth market will take up SMS and MSM enthusiastically, I don't believe it will say double the use of phones. Most people appear to want a phone just for talking. What a surprise!
A 3G phone should allow global roaming, have packet based data facilities (always connected) rather than circuit switched data facilities (a phone call first). Data rates of 144 kbps from a vehicle, 384 kbps for walking speeds, and higher from a fixed location. If these can be managed web browsing and even video would be practical (personally I don't believe data will be as big a money maker as the phone companies hope, nor do I believe they will reach these data rates).
GSM systems are likely to move to the 2.5G GPRS (General Packet Radio System). This combines several simultaneous voice channels and uses them for data. Claims up to 115 kbps, but I've heard that the few existing ones top out at about 30 kbps. It is a software modification at the base station, and a phone capable of handling the multiple channels (which many can). Don't expect too much from this, although for some purposes it is clearly better than GSM.
Enhanced Data Rates for Global Evolution (EDGE) is the likely 3G GSM system. It uses GPRS and 8PSK modulation to aim for a 384 kbps. IS-136 TDMA is also likely to go that way, perhaps with Motorola's Aspira.
GSM carriers aiming for 4G may use WCDMA, with frequency division duplexed 5 MHz paired channels. This takes a lot of bandwidth, which may not be available. It is obvious that the spectrum space will not be there in the USA for 3G, as the bands used worldwide are held for military and government use in the USA.
There are also a variety of CDMA possibilities, indicating there will not be a single world wide mobile phone system any time soon.
The USA situation is complicated by the FCC demand that all cell phones have a position location system (claimed spuriously to be for 911 emergency calls) by the end of 2002. Three possibilities are inbuilt GPS, cell triangulation, or a hybrid base station GPS and special carrier. As well as the invasion of privacy and position tracking implications, this will also lead to location based advertising methods. Better learn to remove the batteries from your cell phone (some can already be switched on remotely). This may have an impact on the use of phones in crime, although as stolen phones may be used, perhaps not.
Existing GSM Phone equipment
International Mobile Equipment Number, different for each phone, and built into each GSM phone. You need to know this for potential tracking purposes if your phone is stolen. Many phones will show this IMEI number if you enter *#06#
About 10,000 phones a month were being stolen in Australia by the end of 2000, about 40% of these from motor vehicles, and mostly from the middle of cities. The old analogue phones stopped working once the theft was advised and the account was closed. The country area replacement CDMA phones stopped once their Equipment Service Number (ESN) was reported. In contrast, GSM phones can continue to be used. They contain a removeable Subscriber Identity Module (SIM) card. When the account is stopped, the thief can put a different prepaid SIM card in. As far as I can tell, little real police or phone company effort is made to track the IMEI numbers built into the phone, so stolen phones can continue to be used with low risk.
Using a password can reduce the potential loss if a phone is stolen.
The Australian Mobile Telecommunications Association (AMTA), in conjunction with RNR International Marketing launched a Mobile Phone Handset Registry System called 'Find A Phone', which is a centralised holding and management system containing lost and stolen mobile phone IMEI numbers. These numbers are automatically listed with 'Find A Phone' whenever a mobile phone is reported as lost or stolen to a mobile network. If this copntinues to operate, you can check for stolen phones using this via www.findaphone.com.au
Giving children phones to help make them safer strikes me as one of the most idiotic ideas I've ever heard. Rumaging around in a bag for a phone probably isn't as safe as running to the nearest house or other adult. Meanwhile, in Britain, street phone theft accounts for a third of all muggings. Children are five times as likely to be victims as are adults. Almost half of all robberies involving children are for mobile phones.
Fixed Phone Connection Prices
Telstra's wholesale pricing, for access to the last mile copper by other operators, did another flipflop in late 2003. Telstra claimed their real costs were pretty high. Then they put out a second try at pricing, which they called their first undertaking. Now under pressure from the ACCC they have come up with another set of pricing which is even cheaper!
- Local call resale: 17.5c, then 14.5c, now 13.6c.
- Interconnection per minute: 3c, 1.7c, 1.25c.
- CBD unconditioned line per month: $44, $20, $13.
Lots of politics associated with these prices, and very little I suspect to do with actual costs, which are shifting faster than quicksand. For example, some large corporates are getting fixed to mobile rates of 15c a minute, against 60c a minute for small business. Local calls at 8c against 22c. Mobile data at $3 a month, against $10 minimums.