Code Division Multiple Access

Already bought a CDMA phone?
Maybe a lot of people eager to convert their GSM phone to CDMA phone because of it cheap pulse phone price. I want to do it to but a have obstable in my finance :-)

CDMA or Code division multiple access is a form of multiplexing and a method of multiple access that divides up a radio channel not by time (as in time division multiple access), nor by frequency (as in frequency-division multiple access), but instead by using different pseudo-random code sequences for each user. CDMA is a form of "spread-spectrum" signaling, since the modulated coded signal has a much higher bandwidth than the data being communicated.In electronics, telecommunications and computer networks, multiplexing (short muxing) is a term used to refer to a process where multiple analog message signals or digital data streams are combined into one signal. The aim is to share an expensive resource. For example, in electronics, multiplexing allows several analog signals to be processed by one analog-to-digital converter (ADC), and in telecommunications, several phone calls may be transferred using one wire. In communications, the multiplexed signal is transmitted over a communication channel, which may be a physical transmission medium. The multiplexing divides the capacity of the low-level communication channel into several higher-level logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing, can extract the original channels on the receiver side.

CDMA also refers to digital cellular telephony systems that make use of this multiple access scheme, such as those pioneered by QUALCOMM, and W-CDMA by the International Telecommunication Union or ITU.
CDMA has been used in many communications and navigation systems, including the Global Positioning System and in the OmniTRACS satellite system for transportation logistics.
A number of different terms are used to refer to CDMA implementations. The original U.S. standard defined by QUALCOMM was known as IS-95, the IS referring to an Interim Standard of the Telecommunications Industry Association (TIA). IS-95 is often referred to as 2G or second generation cellular. The QUALCOMM brand name cdmaOne may also be used to refer to the 2G CDMA standard. CDMA has been submitted for approval as a mobile air interface standard to the ITU International Telecommunication Union.
Whereas the Global System for Mobile Communications (GSM) standard is a specification of an entire network infrastructure, the CDMA interface relates only to the air interface—the radio part of the technology. For example GSM specifies an infrastructure based on internationally approved standard while CDMA allows each operator to provide the network features as it finds suited. On the air interface, the signalling suite (GSM: ISDN SS7) work has been progressing to harmonise these.
After a couple of revisions, IS-95 was superseded by the IS-2000 standard. This standard was introduced to meet some of the criteria laid out in the IMT-2000 specification for 3G, or third generation, cellular. It is also referred to as 1xRTT which simply means "1 times Radio Transmission Technology" and indicates that IS-2000 uses the same 1.25 MHz carrier shared channel as the original IS-95 standard. A related scheme called 3xRTT uses three 1.25 MHz carriers for a 3.75 MHz bandwidth that would allow higher data burst rates for an individual user, but the 3xRTT scheme has not been commercially deployed. More recently, QUALCOMM has led the creation of a new CDMA-based technology called 1xEV-DO, or IS-856, which provides the higher packet data transmission rates required by IMT-2000 and desired by wireless network operators.
The QUALCOMM CDMA system includes highly accurate time signals (usually referenced to a GPS receiver in the cell base station), so cell phone CDMA-based clocks are an increasingly popular type of radio clock for use in computer networks. The main advantage of using CDMA cell phone signals for reference clock purposes is that they work better inside buildings, thus often eliminating the need to mount a GPS antenna on the outside of a building.
This CDMA system is frequently confused with a similar but incompatible technology called Wideband Code Division Multiple Access (W-CDMA) which forms the basis of the W-CDMA air interface. The W-CDMA air interface is used in the global 3G standard UMTS and the Japanese 3G standard FOMA, by NTT DoCoMo and Vodafone; however, the CDMA family of US national standards (including cdmaOne and CDMA2000) are not compatible with the W-CDMA family of International Telecommunication Union (ITU) standards.
Another important application of CDMA — predating and entirely distinct from CDMA cellular — is the Global Positioning System or GPS.
The size of a given cell depends on the power of the signal transmitted by the handset, the terrain, and the radio frequency being used. Various algorithms can reduce the noise introduced by variations in terrain, but require extra information be sent to validate the transfer. Hence, the radio frequency and power of the handset effectively determine the cell size. Long wavelengths need less energy to travel a given distance vs. short wavelengths, so lower frequencies generally result in greater coverage while higher frequencies result in lesser coverage. These characteristics are used by mobile network planners in determining the size and placement of the cells in the network. In cities, many small cells are needed; the use of high frequencies allows sites to be placed more-closely together, with more subscribers provided service. In rural areas with a lower density of subscribers, use of lower frequencies allows each site to provide broader coverage.
Various companies use different variants of CDMA to provide fixed-line networks using Wireless local loop (WLL) technology. Since they can plan with a specific number of subscribers per cell in mind, and these are all stationary, this application of CDMA can be found in most parts of the world.
CDMA is suited for data transfer with bursty behaviour and where delays can be accepted. It is therefore used in Wireless LAN applications; the cell size here is 500 feet because of the high frequency (2.4 GHz) and low power. The suitability for data transfer is the reason for why W-CDMA seems to be "winning technology" for the data portion of third-generation (3G) mobile cellular networks.
Hhh another new technology, isn't it:-)?

Handphone+Bluetooth Adapter+PC= Internet Connection??

A Year ago i bought a SE T610 SonyEriccson mobile phone due to my old motorola retirement. This phone has a bluetooth feature that i like so much, coz by this feature i could connect my phone to my computer so that i didnt have to go to the shop and spend some money to add ringtone or wallpaper. But to do that i have to buy another device, a bluetooth adapter for my computer.

Evidently we could connect our PC to the web by using handphone. Maybe for the first time i think that is not possible,but you now in this world impossible is nothing :-). But how??

1.First Step: Preparation
We need to prepare some stuff
-PC
-bluetooth adapter
-handphone (GSM/CDMA) that has bluetooth feature and already set for GPRS connection
- and of course enough phone pulses :-)

2.Second Step: GPRS setting
If the phone GPRS hasn't set yet we can set it for instance who use TELKOMSEL by send a sms message "GPRS" to 6616 or if you use INDOSAT send "GPRS" to 3000. Follow the instruction well and the GPRS setting will be installed to ur phone.

3.Third Step: Phone Setting
Activate the bluetooth feature of the phone. For SE T610 go to Connectivity-Bluetooth-Turn On

4.Fourth Step: Bluetooth Adapter setting
After the setting stuff accomplished, we can go straight to the PC. Make sure the bluetooth adapter driver has already installed. The driver usually come with the package when we bought one. After the installation, plug the adapter in. Start the bluetooth application at the PC. Click "My Buetoooth-Bluetooth Device Discovery" and the program will searh for new device. If there is no problem our handphone name will appear in the bluetooth application. Clck twice in the phone icon and the services will be available. There are several services provided by the application, choose "Bluetooth dial-up networking service".

5.Last Step:Connecting to Internet
You have to remember the CID number on your phone setting. In SE T610 you can see the CID through : Connectivity-Data Comm-Data Accounts-indosatgprs(if you use indosat provider)-CID
In my phone the CID for Telkomsel (because i use simpati card) is 1 so use that number to connect
There will be some form to fill in Bluetooth DUN Modem Connection
username : (just empty this form)
password :(just empty this form)
dial :99***CID# (in this case 99***1# )

explaination :
if there is several gprs setting on your phone:
1. Sat-Gprs
2. Telkomsel
3. Excel
4. IM3
5. etc

For connecting with setting number 1 use: *99***1#
for setting number 2: *99***2#
for setting number 3: *99***3#,
etc, its depend which connection you shall use
If everything run well you will be able to connect to the web immediately

The price each Kb for SIMPATI is Rp.12,- and MENTARI Rp.5,-
So which one will you choose is depend on your own taste and wallet thickness:-)
Enjoy the technology

there something about algorithm and program

All of my student in the senior high complained me when i tough them about algorithm before entering programming stuff . They protest why didnt i just teach them straight away to the main dishes, programming language.

They just calmed down as soon as i explained about the importance of algorithm.

So who is the algorithm really is?

An algorithm (pronounced AL-go-rith-um) is a procedure or formula for solving a problem. The word derives from the name of the mathematician, Mohammed ibn-Musa al-Khwarizmi, who was part of the royal court in Baghdad and who lived from about 780 to 850. Al-Khwarizmi's work is the likely source for the word algebra as well.

A computer program can be viewed as an elaborate algorithm. In mathematics and computer science, an algorithm usually means a small procedure that solves a recurrent problem.

In computing, a program is a specific set of ordered operations for a computer to perform. In the modern computer that John von Neumann outlined in 1945, the program contains a one-at-a-time sequence of instructions that the computer follows. Typically, the program is put into a storage area accessible to the computer. The computer gets one instruction and performs it and then gets the next instruction. The storage area or memory can also contain the data that the instruction operates on. (Note that a program is also a special kind of "data" that tells how to operate on "application or user data.")

Programs can be characterized as interactive or batch in terms of what drives them and how continuously they run. An interactive program receives data from an interactive user (or possibly from another program that simulates an interactive user). A batch program runs and does its work, and then stops. Batch programs can be started by interactive users who request their interactive program to run the batch program. A command interpreter or a Web browser

is an example of an interactive program. A program that computes and prints out a company payroll is an example of a batch program. Print jobs are also batch programs.

When you create a program, you write it using some kind of computer language. Your language statements are the source program. You then "compile" the source program (with a special program called a language compiler) and the result is called an object program (not to be confused with object-oriented programming). There are several synonyms for object program, including object module and compiled program. The object program contains the string of 0s and 1s called machine language that the logic processor works with.

The machine language of the computer is constructed by the language compiler with an understanding of the computer's logic architecture, including the set of possible computer instructions and the length (number of bits) in an instruction.