What is WCDMA

WCDMA stands for Wideband Code Division Multiple Access. It is one of the main systems used for third generation, or 3G, mobile communication networks. The term is often used interchangeably with UMTS, which stands for Universal Mobile Telecommunications Systems. Technically WCDMA is merely one example of UMTS technology.
The most prominent use of WCDMA is in Japan where the country's largest mobile phone operator, NTT DoCoMo uses the technology. It was DoCoMo which originally developed WCDMA. The firm then successfully lobbied for it to be accepted as an international standard.
WCDMA is used across the world in dozens of countries. It is most prominently used in Asia and Europe. Outside of Japan, the UMTS name is generally used for marketing the system.

The WCDMA system combines two main types of mobile phone technology: CDMA and GSM, which stands for Global System for Mobile communications. In the United States, most cellphone network providers use only one of these two technologies. One of the main reasons WCDMA has struggled to get a foothold in the US is that it uses two channels, each covering 5Mhz. This is a relatively large "chunk" of the airwaves, which has been problematic as the US was slow to allocate new frequencies specifically for 3G systems.

There are several key advantages to WCDMA. One is that each transmitter is assigned an identification code. This means that data from multiple transmitters can be carried over the same frequency in the same geographical area at the same time without interference or loss of signal strength.
The system also uses power control. This adjusts the strength of the signal transmitted by each cellphone so that it reaches the nearest transmitter at the same strength, regardless of how far away the phone is. This avoids the transmitter receiving signals which are excessively strong or weak, which could limit the transmitter's efficiency
 

What is 4G UMTS

Fourth-Generation universal mobile telecommunications system, often abbreviated 4G UMTS, is a wireless telecommunications data transfer standard. Though there are a number of devices that claim to use 4G UMTS, the original standards set by the International Telecommunication Network are not yet met by these devices. 4G UMTS uses many of the same devices and much of the same infrastructure as Third-Generation UMTS (3G UMTS).
UMTS, sometimes referred to as wideband code division multiple access (WCDMA), uses Internet protocol (IP) technology to connect wireless users with the Internet. First developed in the 1990s, UMTS is a reliable network that is frequently used to transmit data and voice. Mobile phones, laptop computers and other devices can connect to the Internet and make voice calls over a UMTS system.

Though not yet in wide use as of 2011, 4G UMTS calls for significant speed increases over the UMTS standard, which has been used since 2001. 3G UMTS requires that data be transferred at a peak rate of at least 200 kilobytes per second. In 4G UMTS, data must download at a rate of 100 megabytes per second in mobile devices and at 1 gigabyte per second for electronics connected to a local wireless access hub. Both 3G UMTS and 4G UMTS require the simultaneous transfer of voice and data, which was a requirement first established during the switch from second generation to third protocol. 3G UMTS and 4G UMTS can both transfer information using the same infrastructure.
A number of pre-4G devices have been on the market starting as early as 2006. Though these devices are not up to 4G standards, they are considerably faster than the 3G standard. In December 2010, the International Telecommunication Union, which is managed by the United Nations, determined that some of the pre 4G technologies already on the market could label themselves as 4G even though they did not quite reach the levels required by the standards. 

4G UMTS is one of a number of standards that wireless carriers can use. It is a common choice among carriers, mainly because the infrastructure has been around for a long time. Ultra Mobile Broadband (UMB) is a Qualcomm CDMA implementation that offers higher speeds than 3G UMTS though less than 4G UMTS. Many companies were dissatisfied with aspects, however. These companies may choose to work with UMTS instead of UMB as the 4G technologies and systems are released.

What is 3G Broad Band

Third generation (3G) broadband, primarily used by telecommunications providers and their customers, offers mobile Internet through specifically enabled devices. Devices that access 3G broadband have the capacity to browse websites, download content, and access other Internet services from a mobile location. At the time of its release, 3G broadband proved to be unrivaled in terms of mobile Internet technology.
3G utilizes wireless technology standards such as Enhanced Data rate for Global System for Mobile communications Evolution (GSM Edge), Universal Mobile Telecommunications System (UMTS), Code division multiple access (CDMA), and Worldwide Interoperability for Microwave Access (WiMAX) to create high speed data and voice mobile networks. Unlike its predecessor 2G, 3G presents voice and data services at high rates, coupled with the ability to use voice and data simultaneously. 3G download speeds reach as high as 14.4 Mbit/s while upload speeds reach as high as 5.8 Mbit/s. 3G standards are defined by the International Telecommunication Union as IMT 2000, with an aim to facilitate growth, increase bandwidth, and support diverse applications.

3G broadband was first released in 2001, with WiMax introduced to the telecommunications market in 2007. Upon 3G broadband's initial release, it was launched by NTT DoCoMo in Japan. Following this launch, 3G spread to other countries in Asia and Europe before reaching the United States, where the first operator was Monet Mobile Networks, followed by Verizon Wireless, which launched 3G in October 2004. Generally speaking, the 3G broadband market is still monopolized by cell phone providers, who offer the services primarily to cell phone users.

3G broadband data rates vary depending on the location and provider, but is still a significant improvement from 2G. This previous generation was noted for slow data transmission. In addition to rate improvements, security levels have been intensified in 3G broadband.
Aside from cellular phones, 3G broadband has also become accessible through much smaller devices, called dongles. Dongles connect other devices, such as computers, to mobile Internet services. 3G broadband technology has yet to reach wide spread use and coverage, and also remains surpassed by conventional Internet for bandwidth levels