| Introduction to 3G: | | | | in either FDD or TDD mode allows for efficient |
| The Third Generation (3G) will be digital mobile | | | | utilization of the available spectrum |
| multimedia offering broadband mobile communications | | | | Key Features of WCDMA: |
| with voice, video, and graphics, audio and other | | | | The key operational features of the WCDMA radio |
| information. | | | | interface are listed below: |
| The mobile communications industry has evolved in | | | | 1. Support of high data rate transmission: 384 Kbps |
| three stages, and correspondingly three generations of | | | | with wide area coverage, 2 Mbps with local coverage. |
| mobile phones have emerged thus far. Each one has | | | | 2. High service flexibility: support of multiple parallel |
| provided more flexibility and usability than the previous | | | | variable rate services on each connection. |
| ones.o (1G) Analog: Analog phones helped to make | | | | 3. Both Frequency Division Duplex (FDD) and Time |
| voice calls inside one's country without roaming | | | | Division Duplex (TDD). |
| facilities.o (2G) Digital mobile phone systems added fax, | | | | 4. Built in support for future capacity and coverage |
| data and messaging capabilities as well as voice | | | | enhancing technologies like adaptive antennas, |
| telephone service in many countries offering worldwide | | | | advanced receiver structures and transmitter diversity. |
| roaming.o (3G) Multimedia services add high speed | | | | 5. Support of inter frequency hand over and hand over |
| data transfer to mobile devices, allowing new video, | | | | to other systems, including hand over to GSM. |
| audio and other applications (including Internet services) | | | | 6. Efficient packet access. |
| through mobile phones. | | | | WCDMA Technical Specifications |
| 3G, based on WCDMA technology, will bring these | | | | Multiple Access Scheme: DS-CDMA |
| incompatible standards together. | | | | Duplex Scheme: FDD/TDD |
| Features of 3G: | | | | Packet Access Dual mode: (Combined and dedicated |
| 1. With 3G, the information is split into separate but | | | | channel) |
| related packets before being transmitted and | | | | Multirate/Variable rate scheme: Variable spreading |
| reassembled at the receiving end. Packet switched | | | | factor and multi-code |
| data formats are much more common than their circuit | | | | Chip Rate: 3.84 Mcps |
| switched counterparts. | | | | Carrier Spacing: 4.4-5.2 MHz (200 kHz carrier raster) |
| 2. The World Wide Web (WWW) is becoming the | | | | Frame Length: 4.4-5.2 MHz (200 kHz carrier raster |
| primary communications interface. People access the | | | | Inter Base Station synchronization: FDD: No |
| Internet for entertainment, services, and information | | | | synchronization needed |
| collection, the intranet for accessing enterprise | | | | TDD: Synchronization required |
| information and connecting with colleagues and the | | | | 3G mobile communication Technology with WCDMA: |
| extranet for accessing customers and suppliers. | | | | Providing good in-building coverage plays an important |
| These are all derivatives of the World Wide Web | | | | role in attracting and retaining mobile subscribers. |
| aimed at connecting different communities of interest. | | | | Ordinarily, coverage from the macro network extends |
| Information and other resources are being stored in | | | | into buildings but should be complemented by |
| remote Web servers, which serve the various needs | | | | dedicated in-building systems. Greater data capacity |
| of human beings through Web browsers at their ends. | | | | and the ability of third-generation networks to provide |
| 3. Speeds of up to 2 Megabits per second (Mbps) are | | | | high-speed data services increase the demands put on |
| achievable with 3G. The data transmission rates will | | | | the cellular network. Subscribers have great |
| depend upon the environment, the call is being made in, | | | | expectations regarding third-generation services. |
| however, only indoors and in stationary environments | | | | Therefore, when introduced, the new services must |
| that these types of data rates will be available. For | | | | (at very least) be available everywhere |
| high mobility, data rates of 144 kbps are expected to | | | | second-generation services can be found. |
| be available. | | | | Notwithstanding, many third-generation networks |
| Implementation of WCDMA in 3G: | | | | deployed to date have been designed primarily to |
| Wideband Code-Division Multiple-Access (W-CDMA) is | | | | provide good coverage in outdoor environments-not |
| one of the main technologies for the implementation of | | | | inside buildings. As a consequence, users of early |
| third-generation (3G) cellular systems. | | | | implementations of wideband code-division multiple |
| The implementation of W-CDMA will be a technical | | | | access (WCDMA) rate third-generation services |
| challenge because of it's complexity and versatility. | | | | poorly compared to second-generation services. |
| The complexity of W-CDMA systems can be viewed | | | | Conclusion: |
| from different angles: the complexity of each single | | | | The major advantage is increased capacity through |
| algorithm, the complexity of the overall system and the | | | | more efficient use of the spectrum. Greater capacity |
| computational complexity of a receiver. W-CDMA | | | | enables the WCDMA wireless network to handle |
| link-level simulations are over 10 times more | | | | higher call density at a lower cost. Implementation of |
| compute-intensive than current second-generation | | | | WCDMA improved the voice quality, system |
| simulations. In W-CDMA interface different users can | | | | performance and Mobile battery life. |
| simultaneously transmit at different data rates and | | | | Reference: |
| data rates can even vary in time. UMTS networks | | | | 1. Rakesh Arora, "Recent advances in wireless data |
| need to support all current second generation services | | | | networking". |
| and numerous new applications and services. | | | | 2. Hans Beijner, "The Importance Of In-Building Solutions |
| Different modes of operation in WCDMA: | | | | In Third-Generation Networks". |
| In WCDMA, there are two different modes of | | | | 3. Juha Korhonen, "Introduction to 3G Mobile |
| operation possible:o TDD: In this duplex method, uplink | | | | Communications". |
| and downlink transmissions are carried over the same | | | | 4. Ramjee Prasad, "Towards a Global 3G System" |
| frequency band by using synchronized time intervals. | | | | 5. Jeffrey Bannister, Paul Mather, Sebastian Coope, |
| Thus time slots in a physical channel are divided into | | | | "Convergence Technologies for 3G" |
| transmission and reception part.o FDD: The uplink and | | | | 6. MR Karim, Mohsen Sarraf, "W CDMA and |
| downlink transmissions employ two separated | | | | Cdma2000 for 3G Mobile Networks" |
| frequency bands for this duplex method. A pair of | | | | 7. Keiji Tachikawa, "W CDMA Mobile Communications |
| frequency bands with specified separation is assigned | | | | System" |
| for a connection. Since different regions have different | | | | 8. |
| frequency allocation schemes, the capability to operate | | | | |