History and Advantages of CDMA Technology

CDMA (code division multiple access) is a multiple access technology, where each user uses a unique code contained in the access channel in the system. 

In CDMA, the information signal at the transmitter dicoding and dispersed with a bandwidth of 1.25 MHz (spread spectrum), then on the side of the repeater is decoding to obtain the required information signal. The experts agree that mobile phone technology sophistication far beyond GSM CDMA is now used by many mobile phone operators in Indonesia. CDMA tariffs will be far below the GSM because of its investment cost is very cheap. 


CDMA technology was initially used in military radio communication United States (U.S.), began in 1990 patent granted to Qualcomm, Inc.. and serve as a digital cellular standard in the U.S. since 1993. Therefore do not be surprised if this technology is very safe because it can not be duplicated (cloned). 

So this technology is very suitable for the use of telephone banking services, such as transfers, check balances, etc.. GSM is supported by the European countries more quickly soared to the number of users around the world which today has reached over 700 million. While the number of CDMA subscribers reached 120 million. GSM and CDMA variants with initial IS-95 A also appear at the same time in the early years of the 90s generation mobile phone technology is categorized in the 2nd (2G). 

Some of the advantages of CDMA-2000 (1X) when compared with GSM as follows: 
 
1. As military technology
CDMA is very resistant to weather disturbances and interference, therefore CDMA is very low noise resulting in excellent sound quality. Even in the rain very lebatpun sound quality is still within the limits of which can still be tolerated. 

2. CDMA can not be duplicated (cloned) 
Because every customer is given a different code (unique). These codes are very difficult to track because it is random. 

3. Very low coverage (1 / 100 GSM)  
CDMA mobile phone allows efficient in battery consumption, so it can operate longer to speak or stand by.

4. Capacity of CDMA subscribers per base station can reach 6000 (10 GSM).  
This is due to CDMA is more efficient in the use of frequencies. All CDMA base stations operating at the same frequency, so it does not require complex calculations in a configuration set-rasinya. The amount of capacity per BTS makes the investment costs incurred are very low. In addition, CDMA-2000 (1X) operating at 800 MHz frequency spectrum. This will create a broad base stations coverage far greater than GSM. So just need fewer base stations to cover the same areas when compared with GSM. 

5. CDMA-2000 (1X)  
Can send data at speeds up to 144 kbps, while GSM 9.6 Kbps. So that can support SMS, MMS, play games and download data via the Internet.

Best GSM modem, Huawei E220 or Sierra 885u?

In this day and age would need the Internet to increase from year to year. For though we've entered the information age.

And one tool that must be present when their existence is a modem connection to the Internet.

We have had many good modem models of CDMA and GSM. On this occasion I tried to compare where the GSM modem is actually the best according to the results of some references on the Internet. Here it is the result.

Huawei E220



With tiny design and high speed, Huawei E220 USB modem to change the mini fashion for the elite. The irresistible creation features the eye-catching sleek design and great speeds up to 3.6Mbps. With a USB cable can be used by both laptops and desktop computers.

Specification

Features

    * HSDPA / UMTS / EDGE / GPRS / GSM
    * HSDPA packet data service with a maximum transmission rate of 3.6Mbps
    * UMTS packet data service with a maximum transmission rate of 384kbps
    * EDGE packet data service with a maximum transmission rate of 236.8kbps
    * SMS service
    * Auto installation, Convenient for use

Speed

    * Download = 7.2 Mbps
    * Upload = 384 Kbps

Frequency Specifications

    * HSDPA / UMTS 2100MHz
    * GSM / GPRS / EDGE 900/1800/1900MHz

Operating System

    * Windows 2000, Windows XP, Windows Vista & Mac OS

Weight: <50 g

Price: $ 56.00


Sierra Wireless Compass 885u

Sierra Wireless Compass USB Modem 885u offers seamless high-speed wireless connections for both Mac, Windows either by using the Desktop and Laptop Computers on HSUPA networks. It's a simple USB modem that includes TRU-Install, no installation CD, memory MircoSD.

Features

    * Wireless download speed up to 7.2 Mbps and upload to 2 Mbps (upgradeable to 5.76 Mbps) Wireless download speed up to 7.2 Mbps and upload to 2 Mbps
    * Familiar USB connection
    * Small, durable, fixed design
    * MicroSD memory expansion slot
    * TRU-Install, automatic software installation

Speed

    * Max. Download = 7.2 Mbps
    * Max. = 2 Mbps upload

Network

    * HSDPA, HSUPA, UMTS, EDGE, GPRS, GSM

Operating System

    * Mac OS X, Windows 7, Windows 7 Mobile Broadband, Windows Vista, Windows XP

Weight: 30 g

Price: $ 61.00


Conclusion:

Apart from common features offered by each product and from the reviews, I recommend to select the modem is Sierra Wireless Compass 885u. Because the modem is Sierra Wireless Compass 885u more resistant to heat, there is also WLAN (Wi-Fi Build in), slot MircoSD and ROHS Compliant (environmentally friendly).

And needs to be underlined, to obtain the maximum speed is nothing to do with your ISP (Internet Service Provider) what you wear. And how strong the signal is obtained and users each ISP facilities in the area.

Comparison of GSM and CDMA Modem

Actually, if both of them than there are 3 things to note:
1. From the economic side
2. In terms of network
3. In terms of the intended use

Judging from the 3 factors above, this is the advantages and disadvantages of GSM and CDMA Modem:

1. Excess GSM modem:
- Modem GSM has a very extensive network coverage
- almost all places in Jakarta are getting a 3G or HSDPA or HSUPA
- Prices are already 3G GSM modems are relatively cheap price

2. The advantages of CDMA modem:
- Broadband Cellular Data and a separate communication, so that stable connectivity
- the cheapest monthly subscription price.

3. GSM modem Disadvantages:
- Because the access point and cellular data does not separate the connectivity is less stable.
- The price is still expensive monthly subscriptions.

4. CDMA modem Disadvantages:
- The price is still expensive modem
- CDMA network is still not widely

The speed difference GPRS, 3G, and HSDPA

How is the difference speed about GPRS, 3G and HSDPA?

1. GPRS (115 kb/s)

GPRS speed is still tolerable is roughly twice that of dial up connection so it is still comfortable easy to download small files, browsing, chatting, streaming bit. The advantage coveragenya area already evenly. In practice the highest speed obtained an approximately 14kb/s average speed gained about 9-0 kb/s


2. 3G (320 kb/s)

3. HSDPA (3,2 mb/s)

Differences Data Access GPRS - EDGE - 3G/UMTS - 3.5G/HSDPA

This article discusses a bit about the differences only four such data access (GPRS - EDGE - UMTS - HSDPA). Before there were four such data access, there are several other types of data access, the CSD (Circuit Switched Data).

GPRS (General Packet Radio Service): 
a technology used for sending and receiving data packets. GPRS is often called 2.5G technology. Facilities provided by the GPRS: e-mail, MMS (picture messages), browsing the Internet. In theory GPRS provide access speeds between 56kbps to 115kbps.

EDGE (Enhanced Data for Global Evolution):  
the development of GSM technology, the average has 3 times speed of GPRS speeds. EDGE access speed is theoretically about 384kbps. EDGE provides facilities like GPRS (e-mail, MMS, and browsing).

UMTS (Universal Mobile Telecommunications Service): 
Further development of EDGE. UMTS is often called third generation (3G). In addition to providing Internet access facilities (e-mail, MMS, and browsing), UMTS also provides video streaming, video conferencing, and video calling *). In theory UMTS access speeds around 480kbps.

HSDPA (High Speed ​​Downlink Packet Access): 
is a further development of 3G data access. HSDPA is often referred to as generation 3.5 (3.5G) for HSDPA is still running on the 3G platform. In theory the same speed HSDPA data access, such as 480kbps, but it was definitely faster HSDPA. If not what good is creating faster HSDPA. The more exact the better new technologies.

All four data access over a modem implemented on mobile phone / cell phone, there is also a special modem that is used for connection.

Modem Knowledge and Functionality

 
For those of you who used to surf at home would know where his name modem. Without a modem, we will not be able to surf or her email on the internet. Modem stands for modulator demodulator, which is the hardware that makes a computer capable of converting data from / into the analog form (sound signal) and digital.

Modulator is the part that convey information signal into a carrier signal (Carrier) to be sent to the recipient via cable media or media without wires (wireless).

Modulators are currently on the sender. While the demodulator is the opposite of the modulator, which converts the signal contains data or messages from the carrier signal (carrier) received from the sender so that information can be processed digitally.

Demodulator is located at the receiver. Because the function of the modulator and demodulator is a function that reverses, then surely it can be concluded that this modem is a two-way communication system (duplex).

How Modem Work

In use, the modem charge of changing the data in the form of analog and digital.

When the computer is connected to a cable internet phone for later use, if the computer we will upload / send data, the information / data from a computer in digital form is converted by the modem into analog form to be sent over telephone lines or other media.

When the data / information analog to the destination computer before, then the modem is on the destination computer will turn back the form data (analog) into digital form that can be processed by the computer this goal.

Similarly, when we download the data / files, the data is analog data while on the phone cord, but when entered into our computer, the modem will immediately convert it into digital form to be displayed. This is what allows the computers on the Internet in various parts of the world can interact with each other.


Type of Modem:

Physically, the modem is divided into two kinds: internal and external modems.

Modem Internal

Modem internal merupakan modem yang terpasang di dalam casing komputer. Jika sebuah modem dipasang dengan cara membuka casing komputer lalu menancapkannya ke dalam salah satu slot pada motherboard, maka modem tersebut adalah modem internal.

Contoh lain adalah modem pada laptop. Saat membeli laptop, modem tersebut telah ada di dalam laptop tersebut. Modem internal memerlukan sebuah slot PCI atau slot ISA, tergantung pada interface motherboard. Karena tertancap pada motherboard, maka modem ini menggunakan catu daya yang berasal dari motherboard.

External Modem

Contrary to the internal modem, external modem outside the computer case. The shape of the box and must be connected to the computer and also connected to telephone wires. This modem requires its own power supply. Serial connector can be shaped and can also be shaped USB.

There are two types of external modems, the cable modem and DSL modem. Cable modems are external modems that are commonly used and connected to a computer via an Ethernet card in a PCI slot. While the DSL modem is a modem for high speed internet.

Striking difference between the internal and external modems are:
- Generally, an external modem cost more expensive than internal modems.
- External Modem is a separate / outside of the computer. Meanwhile, an internal modem installed directly on the motherboard expansion slot.
- external modem has an indicator which allows us to monitor the status of the modem. While the internal modem does not have a status indicator.

Other types of modem : 

Cable Modem
As the name implies, a cable modem is a cable axis, the cable television network that provides bandwidth better than dial-up modem commuter. Access is fast enough, ie for downstream transmission up to 38 Mbit / s and upstream transmission up to 1 Mbit / s.

 




Modem DSL-Modem DSL (Digital Subscriber Line)
DSL modem is divided into two kinds, namely ADSL (Asymetric Digital Subscriber Line) and SDSL (Symetric Digital Subscriber Line).
 








Wireless modem and phone modem, Wireless Modem / Phone Modem
With the development of communication technology, the phone can function as a modem, which consists of a GSM modem, CDMA Modem, 3G modem, and modem results to other development such as WCDMA, HSDPA, and others.

 




Installing Modem
All computer hardware has a driver (the software controls the hardware detection) to be able to use it. This also applies to the modem. After we connect the modem to the computer via the connector, we also have to install a driver program which typically have been provided a package with the modem.