Understanding WCDMA

Understanding WCDMA

3G technology also comes in various forms and platforms. Understanding the major ones will help you decide which one is the right tool. You should also tell the technical details, to know if you are getting the right kind of efficiency and accessibility. Getting information from the internet other various sources will never be as convenient as fast, since 3G is the newest available. There are new developments and changes as well to get you ahead.

Knowing WCDMA or UMTS

W-CDMA wideband code-division multiple-access is among the major technologies that implement the 3G or third generation cellular systems. This is founded on the radio access technique suggested by the ETSI Alpha Group. The details and specifications were finalized in 1999. The implementation of W-CDMA is going to be a technical challenge due to the complexity and versatility. The sophistication of the of the systems of W-CDMA can be seen from various aspects.

These are namely the complexity of the overall system, computation complexity of the receiver and the complexity of ever single algorithm. W-CDMA link-level simulations or more than 10 times the compute intensive compared to 2G simulations. In the interface of W-CDMA, the different interface users can immediately transmit at varying information rates, with the data rates even varying in time. Networks of the UMTS are required to support every 2G service, plus new services and applications.

The Technical Details

As for the FDD technical summary, the frequency band will range from 1920 MHz up to 1980 MHz and 2110 MHz and 2170 MHz or frequency division duplex. The minimum frequency band needed is 2 x 5 MHz. The frequency re-use is 1. Carrier spacing is between 4.4 MHz and 5.2 MHz. The most number of voice channels on 2 x 5 MHz is 96 with a spreading factor of 256 UL and AMR or 7.95 Kbps and 98 with a spreading factor of 128 UL and AMR of 12.2 Kbps.

Other Specs

The voice coding includes AMR codecs ranging from 4.75 kHz up to 12.2 kHz, GSM EFR is at 12.2 kHz. SID is also included at 1.8 kHz. The channel coding includes convolutional coding with turbo code for high rate data. The duplexer required is 190 MHz separation with asymmetric connection supported. Tx and Rx isolation is MS:55db and BS:80dB. The Receiver is Rake, while receiver sensitivity is Node B.

More Information

Data type for the device is packet and circuit switch. Modulation is QPSK and pulse shaping is root raised cosine, rolling off at 0.22. The chip rate is 3.84 Mcps while the channel raster is 200 kHz. Maximum user data rate on the physical channel is 2.3 Mbps with a spreading factor of 4, and parallel codes of 3 DL / 6 UL, with limited interference. HSPDA will provide data speeds going as fast as 8 to 10 Mps and 20 Mbps for MIMO systems. The channel it rate is 5.67 Mbps with a frame length of 10 ms or 38400 chips.

There are 15 slots or frames, and 2560 chips. Handovers are soft and softer, plus a hard interfrequency. The power control period has a time slot with a rate of 1500 Hz. Power control step size is 0.5, 1, 1.5 and 2 dB while power control range is UL 80 dB and DL at 30 dB.

About the CDMA2000

About the CDMA2000

There are different platforms or types of 3G technology. Each manufacturer has created and developed some of the most innovative products and mobile handsets. The CDMA2000 is one of the 3 major types. It has different features and tools also that will surely give you a whole new experience, unlike other technologies before it. Here are the details on how to make the most out of the specification.

Introduction

The CDMA2000 specification was created and developed by the Third Generation Partnership Project 2 or 3GPP2, which is a partnership that consists of 5 telecommunication standard bodies: TTC and ARIB in Japan, TTA in Korea, TIA in North America and CWTS in China. CDMA2000 has been implemented to a lot of networks as an evolutionary step from CDMAOne. CDMA2000 gives a full backward compatibility with IS-95B.

CDMA2000 is not contained only into a single IMT-2000 and, although managers have the ability to overlay ACDMA2000 1x system. The system backs 144 Kbps at present, with data rates running up to 307 Kbps in the near future, over the other present CDMAOne network.

Evolving the Technology

CDMA2000 1xEV is the other name of the evolved CDMA2000. This technology will be implemented via a number of steps, namely the 1xEV-DV and 1xEV-DO. 1xEV-DO which represents 1x Evolution Data Only. 1xEV-DV represents 1x Evolution Data and Voice. The two 1xEV CDMA2000 evolution steps will use a carrier standard 1.25 Mhz. 1xEV-DO will most likely be available for the operators CDMA2000 during 2002. The solutions for 1xEV-DV were made available in 2004.

CDMA2000 3x and CDMA2000 1x EV-DO are approved by ITU and IMT-2000 3G basics. CDMA2000 3x is a portion of what the ITU has called IMT-2000 CDMA MC or Multi Carrier. This uses a lower than 5 MHz spectrum via 3x 1.25 MHz channels to provide speeds of more than 2 Mbps.

The Technical Summary

As for the summary of the CDMA2000, the frequency band can be any type or existing and. The minimum frequency band needed for 1x is 2 x 1.25 MHz. For 3x, the required is 2 x 3.75 Mhz. Chip rate for 1x is 1.2288. For 3x, chip rate is 3.6864 Mcps.

The maximum user data rate for 1x is 144 Kbps at present and 307 Kbps in the near future. As for 1xEV-DO, the max rate is 384 Kbps to 2.4 Mbps. The frame length is 5 ms, 10 ms or 20 ms. As for power control rate, it is at 800 Hz. The spreading factors are 4 256 UL.

On WCDMA

W-CDMA in 3G is known as wideband code division multiple access. It is one of the main technologies used for the implementation of 3G cellular systems. It is founded on the radio access method give by ETSI Alpha group with the features and specifications finalized in 1999.

The implementation of W-CDMA will cover very technical details. The complexity of the systems can be seen from various angles. These include the complexity of the receiver, the complexity of the overall system and the complexity of the single algorithm.

In W-CDMA, the interface allows users of 3G to instantly send and get various data rates. UMTS networks will need the support of all current 2G services and several new services and applications. You should consider if this will be the right technique for you.

Bluetooth And Infared

Bluetooth and Infared

With new electrical devices being produced every day, the problem of connecting things is becoming more and more complex in nature. The system that comprises computers and other electronics makes use of varieties of wires, cables, etc.

These parts will communicate through light beams, lasers, radio signals, and infrared. The problem however, is the devices and technology is often the connection between each component. Therefore, most electronic systems aren’t used to their full extent due to the problems and imperfections.

To help simplify things, a solution was created – the solution of Bluetooth. Bluetooth is wireless and automatic, offering users a variety of features that have simplified the art of connection. Bluetooth has revolutionized the standard methods of connecting things to enabling almost anything to be connected to a single system.

Aside from Bluetooth, there are other ways of connecting wireless devices. One example of such is the IR or infrared. Infrared allows low frequency light waves to transmit signals to another component. This technology is easy to create and the cost of putting the IR device into a system is rather low.

Infrared technology is a one to one process. Due to the limitation, you may only send signals from one device to another, similar to a television set and remote control. You can only transmit signals between the two although not with a seperate system.

Aside from the fact that these two natures of infrared are obstacles to acquiring results, these same qualities have worked in advantage to the connection. Infrared devices need to be lined up directly, meaning too little interference can occur between the transmitters and receivers.

The technology behind Bluetooth works by transmitting signals through low frequency radio signals. The path of communication is working on 2.45 GHz, which is the same frequency band used in ISM devices.

Bluetooth Operation

Bluetooth Operation

The networking standards of Bluetooth will transmit data via low power radio frequency. Bluetooth communicates on a 2.45 GHz frequency. This very band of frequency has been set aside by international agreement for the use of industrial and medical devices.

Many devices that you already known and use take advantage of this frequency band. Garage door openers, baby monitors, and the next generation of mobile phones all use this frequency within the ISM band. Ensuring that Bluetooth and the other devices don’t interfere with each other is a crucial part of the design process.

One of the ways Bluetooth will avoid interfering with other electronic devices is by sending out weak signals of around 1 mw. In comparison, even the most powerful of cell phones can transmit a signal of 3 watts.

The low power signals will limit the range of a Bluetooth device to around 32 feet, which cut the chances of interference between your computer and other electronic devices. Even though it has low power, Bluetooth doesn’t require a line of sight between the communicating devices. The walls in your home won’t stop the signal, making it great for rooms throughout the house.

Bluetooth can connect 8 devices at the same time. With each of those devices on the same radius, you may think they would interfere with each other, although it’s very unlikely. Bluetooth utilizes a technique known as low frequency hopping, which makes it harder for more than one device to transmit on the same frequency at the same time.

With this technique, a device will use 79 individual, randomly chosen frequencies within a designated range, which change from one another on a regular basis.

In the case of Bluetooth, the transmitters will change frequency 1,600 times or more every second, meaning that more devices can make full use of the radio spectrum. Since every transmitter of Bluetooth will use spread spectrum automatically, it’s very unlikely that two transmitters will be on the same frequency at the exact same time.

When the Bluetooth devices come within close range of each other, an electronic conversation will occur to determine whether or not they have data to share or whether one needs to take total control. The user doesn’t have any buttons to press or commands to give – as the conversation will occur automatically.

Once the conversation has occurred, the devices will form a network. Bluetooth devices will create a PAN (Personal Area Network) or piconet that may fill a room. Once the piconet has been established, the devices will randomly hop in frequencies.

Bluetooth Technology Intro

Bluetooth Technology Intro

The technology of Bluetooth is nothing new, but in many respects it can still seem like more of a buzz word rather than an accepted technology. You may see the ads for Bluetooth enabled devices, although you still may be wondering what it is.

Capabilities
The Bluetooth definition is a wireless technology that is a worldwide specification for a small form factor, low cost solution that will provide link between mobile devices and other electronic devices.

Similar to 802.11 b/g wireless and many cordless telephone systems, Bluetooth operates on 2.4 GHz radio signals. The 2.4 GHz band seems to be a bit crowded, with interferences between the devices a bit hard to avoid. Telephones are now being offered at the 5.8 GHz frequency band, which will help to remedy this.

The technical specifications of Bluetooth will indicate a maximum transfer rate of 723 kbps with a range of 65 – 328 feet, all depending on the class of that particular device. The speed is a fraction of what is offered by wireless standards, so it’s obvious that Bluetooth doesn’t really pose a threat to replacing your wireless network.

Applications
There are numerous products that will take advantage of Bluetooth capabilities, such as laptops, PDAs, headphones, and even wireless printer adapters.

A lot of laptops out there will include an on board Bluetooth adapter which allows the system to connect to any Bluetooth device right out of the box. For computers that don’t have an adapter built right in, there are several USB adapters available for Bluetooth.

For an awesome technology, Bluetooth is actually hard to compete with. For short range wireless, Bluetooth is easily one of the best. The standard for Bluetooth keeps getting better and better, making it a wireless technology that will be around for years and years to come.