cellphone : Computer Hardware Buyers’ Glossary

cellphone

A device that lets you make voice calls from a battery powered hand held unit. Modern cellphones are also Java powered computers with Internet access. This lets you do web browsing, especially to sites designed for cell phones with trimmed down WAP (Wireless Application Protocol) content, email, and applications that talk to servers.

Today’s cellphones are actually hand held computers with wireless data access. They can do voice, text messaging, and run specialised applications.

In an emergency, sometimes cellphone networks become overloaded and you can’t get through. In that case, use text messaging. It uses a microscopic amount of air time.

To write cellphone software, you need a cellphone OS (Operating System) simulator that runs on your desktop. It is basically a stripped down Java with special classes useful to cellphones. You want to download Java ME and MIDP 2.0, both free from Sun.

Downloading Software to a cellphone

Here are ways from slowest to fastest to get software downloaded into your cellphone.

Analog phones use NAMPS. Time Division MUX (Multiplexor) phones use iDEN or GSM (the world standard). Spread-spectrum digital phones in North America use CDMA.

If you have a T-Mobile, Cingular, or recent new M-mode type service with AT&T (American Telephone & Telegraph), then you have GSM (Global System for Mobile Communications) service. GSM phones are not compatible with CDMA (Code Division Multiple Access) wireless.

In Canada Rogers and Fido are GSM.

If you are signed up with Verizon Wireless or Sprint PCS, you are using CDMA. CDMA phones are not compatible with GSM.

In Canada, Bell and Telus run CDMA.

The world is now flipping to 3G/4G, which is faster and uses bandwidth more efficiently. Even video is possible. Japan and Korea have already done so. The new Apple iPhone 3G uses it. Rogers in Canada is now supporting it partly to support the iPhone.

The evolution will be to lower and lower power with more and more broadcast nodes, perhaps eventually getting down to LAN (Local Area Network) WiFi (Wireless Fidelity) levels and coverage. This downsizing allows faster traffic, more efficient use of the air, and less damage from radio waves. This strategy increases total bandwidth because if each broadcast pollutes a smaller volume of air, it leaves more air to transmit other broadcasts simultaneously.

To define the capabilities of a given cellphone you need to know its configuration and profile. The configuration defines the virtual machine and the bare minimum APIs (Application Programming Interfaces) that must be present. The specification includes the minimum amount of memory, the minimum processor type and processor speed, as well as the minimum processor type and speed.

A profile refers to the APIs for a specific domain. For example, the MIDP (Mobile Information Device Profile) profile defines the API (Application Programming Interface) for mobile phones and wireless PDAs (Personal Digital Assistants). A device might implement more than one profile.

PCS (Personal Communication Services) is an advanced type of cellphone service that uses smaller cells and therefore requires a larger number of antennas to cover a geographic area. PCS phones use frequencies between 1.85 and 1.99 GHz. The idea is to create more bandwidth to handle the exploding volume of traffic and lower the power requirements of the phones.

WiFi wireless Internet Access gives up to 54MBps via IEEE (Institute of Electrical & Electronics Engineers) 802.11. This is primarily an Internet access protocol for laptop computers and handhelds. It is also used for in-home wireless networks that connect to the Internet via a router that connects to the ISP (Internet Service Provider) via traditional DSL (Digital Subscriber Loop) or cable.

Verizon wireless gives 400KBPs download Internet access.

Amazon.com

Amazon is now in the business of selling cellphones and cellphone plans. They carry BlackBerry, Motorola and Nokia — about 40 brands in all. The carry camera phones, music phones, PDA (Personal Digital Assistant) phones, Bluetooth phones, Mp3 player phones and stereo Bluetooth. The have both locked and unlocked phones. They offer Cingular, Nextel, T-Mobile, Sprint and Verizon Wireless plans. They have prepaid phones from NET10, STi Mobile, T-Mobile To Go, TracFone, Virgin Mobile. They have accessories including headsets, shells, skins, cases, holsters, pouches, face plates, antennas, batteries, chargers, and vehicle mounts. Since they carry such a wide variety of stock it is easier to cross-compare to find the best fit.

WiFi Phone

A WiFi phone is one designed to hook into a wireless Internet connection. It is much cheaper to use than a traditional cellphone since it requires no air time to a cellphone tower. It uses ordinary nearby PCs (Personal Computers) connected to the Internet as its cellphone towers. Further, it has much higher bandwidth. You might use one to tie into your home Internet to hook into a VOIP (Voice Over Internet Protocol) system like Vonage and then go to an WiFi-equipped Internet café to use it too.

Ironically, the way to get higher data transmission speeds, and support more customers, is to make the cell phone power lower, and the range smaller, using weaker cellphone towers, but more closely spaced. This is how 4G gets more bandwidth. How could this be? The air is limited in its ability to carry signals. If you use powerful phones, they saturate the air for miles around, preventing others from using that same air. All users surrounding a cellphone tower have to share the same volume of air. Early phone systems handled this by broadcasting on different frequencies, analogous to some people shouting in high pitched voices and others in low pitches. Modern phones handle this by automatically rapidly taking turns many times a second, sending a single packet of digitised sound (much the way an Ethernet LAN works). However, the pie is limited. If you use weaker phones, you saturate a much smaller area, leaving the rest for other people to use. With WiFi, you saturate a space only about the size of an apartment building. You could look at 4G as one step closer to universal WiFi access.

I suspect future phones will be self-adjusting, broadcasting powerfully in rural regions where there are only a few widely spaced towers, and less powerfully in suburbs, and flipping to nearby WiFi in urban areas or in your own home using almost no power at all. If this baffles you, imagine that cellphones worked by shouting for you to the cellphone tower. The further away the tower, the louder it has to shout, and the more it interferes with everyone else. It should be clear now.

5G cellphones that allow 200 Mb/S is coming soon. WiFi is about 300 Mb/S, but it is constantly improving too.

WiFi Cellphones

In 2013-06 there was a big debate as to whether West Vancouver should install unsightly cellphone towers in this posh district.

I would hazard a guess that West Vancouver is already saturated in cellphone towers in the form of home WiFi. You would not need any additional wires or towers to use it. WiFi is far faster than conventional cellphones, and can handle far more phones. All you would need is some software or router firmware to securely route the calls though home WiFi routers.

The phone company would pay you a monthly royalty depending on how much traffic you routed. The software would make sure your WiFi did not route so much it interfered with your own use of the router. It may pay the phone company to upgrade the routers with more powerful ones to cover a larger area where coverage is weak.

Not all cellphones would work with WiFi, but that is not a major problem for a prosperous area like West Van. You could use the existing towers to service tourists who had phones incapable of supporting WiFi.

Because of the geography of West Van, a single tower cannot cover much area. That should be provide even more incentive to a WiFi system than can be expanded indefinitely without erecting any towers.

The main problem would be political: There are three major cell phone players. Telus dominates ADSL (Asymmetric Digital Subscriber Line technology) and Shaw dominates cable. They would all have to co-operate and share revenue with the homeowners. On the other paw, the system would provide far more service, with greater reliability, at much less cost, so there would be more money to go around.

Java

An increasing percentage of cellphones can run Java apps. These are limited to the Java ME API. They include:

Jail-Breaking

Some vendors hobble their cellphones to make them work with only one air-time supplier. Sometimes they block software other than theirs from running on your phone. In the USA it is legal to defeat such measures. Doing so is called jail-breaking.

Fraud

About 1 in six cellphone customers experience fraudulent billing, and surprise much it comes from the cellphone carrier, not petty criminals. Verizon Wireless just paid the largest voluntary fine in FCC (Federal Communications Commission) history — $25 million — for sticking their customers with millions in bogus mystery charges.

The two most common scams are charging tens of thousands of dollars for roaming or downloading a few megabytes, both of which cost the carrier only pennies. I would never sign up for any sort of cellphone billing plan other than a pre-paid card. Presumably, the worst they can rip you off then is the cost of the card, but you had better study the fine print. In Canada, one of the scams is to charge you for international roaming when you go near the US border and a US tower handles your call.

Recovering Lost or Stolen Phones

It would be relatively easy for a carrier to help you find a lost or stolen phone by telling you its current GPS (Global Positioning System) co-ordinates. They do nothing to help. When I found a lost Samsung Smart Phone here are the things it would not tell me that would help track the owner.

Learning More


3G
3G
4G
Bell Mobility: Canadian cellphone provider
BlackBerry
BREW
CDMA
cellphone Specification Comparisons
CLDC
Credo: carrier to raise money for left wing causes
Fido: Canadian cellphone provider owned by Rogers
Google Android
GSM
How cellphones work
HowardForums: discussion board dedicated to mobile phones
iDEN
iPhone
J2SE
Java ME: version of Java used by cellphones
JavaFX
JavaPhone
Jitterbug
KVM
locked cellphone
MagicJack: laptop WIFI VOIP
ME4SE
midlet
MIDP
Mig33 list of Java-powered phones
Mig33: Java app for cellphones for chat, photo-sharing etc
NAMPS
Nokia
OpenMoko: an open source project to create a cellphone
PersonalJava
phone bill shock
Rogers: Canadian cellphone provider
Samsung
Sprint EVO: 4G cellphone
Sun cellphone simulator: CDLC/MIDP toolkit SDK
Telus Mobility: Canadian cellphone provider
UMTS
VOIP
Vonage
WiFi

available on the web at:

http://mindprod.com/bgloss/cellphone.html
ClustrMaps is down

optional Replicator mirror
of mindprod.com
on local hard disk J:

J:\mindprod\bgloss\cellphone.html
logo
Please the feedback from other visitors, or your own feedback about the site.
Contact Roedy.
no blog for this page
IP:[65.110.21.43]
Your face IP:[54.204.134.183]
You are visitor number 13,186.