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WCDMA is designed for multimedia communications including high quality images and video, and access to services with high data rates.
Third generation systems are designed for multimedia communication: with them personto-person communication can be enhanced with high quality images and video, and access to information and services on public and private networks will be enhanced by the higher data rates and new flexible communication capabilities of third generation systems. This, together with the continuing evolution of the second generation systems, will create new business opportunities not only for manufacturers and operators, but also for the providers of content and applications using these networks.
In the standardisation forums, WCDMA technology has emerged as the most widely adopted third generation air interface. Its specification has been created in 3GPP (the 3"d Generation Partnership Project), which is the joint standardisation project of the standardisation bodies from Europe, Japan, Korea, the USA and China. Within 3GPP, WCDMA is called UTRA (Universal Terrestrial Radio Access) FDD (Frequency Division Duplex) and TDD (Time Division Duplex), the name WCDMA being used to cover both FDD and TDD operation.
Throughout this book, the chapters related to specifications use the 3GPP terms UTRA FDD and TDD, the others using the term WCDMA. This book focuses on the WCDMA FDD technology. The WCDMA TDD mode and its differences from the WCDMA FDD mode are presented in Chapter 12.
In addition to WCDMA, the other air interfaces that can be used to provide third generation services are EDGE and multicarrier CDMA (cdma2000). EDGE (Enhanced Data Rates for GSM Evolution) can provide third generation services with bit rates up to 500 kbps within a GSM carrier spacing of 200 kHz . EDGE includes advanced features that are not part of GSM to improve spectrum efficiency and to support the new services. The multicarrier CDMA can be used as an upgrade solution for the existing IS-95 operators and will be presented in more detail in Chapter 13.
The expected frequency bands and geographical areas where these different air interfaces are likely to be applied are shown in Figure 1.1. Within each region there are local exceptions in places where multiple technologies are already being deployed.
The spectrum allocation in Europe, Japan, Korea and the USA is shown in Figure 1.2. In Europe and in most of Asia the IMT-2000 bands of 2 x 60 MHz (1920-1980 MHz plus 2110-2170 MHz) will be available for WCDMA FDD. The availability of the TDD spectrum varies: in Europe it is expected that 25 MHz will be available for licensed TDD use in the 1900-1920 MHz and 2020-2025 MHz bands. The rest of the unpaired spectrum is expected to be used for unlicensed TDD applications (SPA: Self Provided Applications) in the 2010-2020 MHz band. FDD systems use different frequency bands for uplink and for downlink, separated by the duplex distance, while TDD systems utilise the same frequency for both uplink and downlink.
In Japan and Korea, the IMT-2000 FDD band is the same as in the rest of Asia and in Europe. Japan has deployed PDC as a second generation system, while in Korea IS95 is used for both cellular and PCS operation. The PCS spectrum allocation in Korea is different from the US PCS spectrum allocation, leaving the IMT-2000 spectrum fully available in Korea. In Japan, part of the IMT-2000 TDD spectrum is used by PHS, the cordless telephone system.
In China, there are reservations for PCS or WLL (Wireless Local Loop) use on one part of the IMT-2000 spectrum, though these have not been allocated to any operators.
Depending on the regulation decisions, up to 2 x 60 MHz of the IMT-2000 spectrum will be available for WCDMA FDD use in China. The TDD spectrum is also available in China. In the USA no new spectrum has yet been made available for third generation systems. Third generation services can be implemented by refarming third generation systems within the existing PCS spectrum. This will require replacing part of the existing second generation frequencies with third generation systems. For the US PCS band, all third generation alternatives can be considered, but EDGE has an advantage as a narrowband system. With EDGE less spectrum will need to be cleared to deploy third generation services. Multicarrier CDMA and WCDMA can also be considered for refarming.
EDGE can be deployed within the existing GSM900 and GSM 1800 frequencies where those frequencies are in use. These GSM frequencies are not available in Korea and Japan. The total band available for GSM900 operation is 2 x 25 MHz plus EGSM 2 x LO MHz, and for GSM1800 operation 2 x 75 MHz. EGSM refers to the extension of the GSM900 band. The total GSM band is not available in all countries using the GSM system. Later, it will also be possible to refarm WCDMA to the GSM bands, but initially EDGE is the solution to providing third generation services within the GSM bands.
Licensing of the IMT-2000 spectrum is under way. The first IMT-2000 licences were granted in Finland in March 1999, and followed by Spain in March 2000. No auction was conducted in Finland or in Spain. Also, Sweden granted the licenses without auction in December 2000. However, in other countries, such as the UK, Germany and Italy, an auction similar to the US PCS spectrum auctions was conducted.
The UMTS licenses are shown in Table 1.1 in Japan and in those European countries where the licenses have been awarded by December 2000. The number of UMTS operators per country is between 4 and 6.
More frequencies have been identified for IMT-2000 in addition to the frequencies mentioned above. At the WARC-2000 meeting of the ITU in May 2000 the following frequency bands were identified for IMT-2000 use:
It is worth noting that some of the bands listed, especially below 2 GHz are partly used with systems like GSM. What shall be the exact duplexing arrangements etc. is under discussion at the moment.
|2||UMTS services and applications||11|
|3||Introduction to WCDMA||47|
|4||Background and standardisation of WCDMA||61|
|5||Radio access : network architecture||75|
|7||Radio interface protocols||149|
|8||Radio network planning||185|
|9||Radio resource management||231|
|11||High-speed downlink packet access||307|
|12||Physical layer performance||347|
|13||UTRA TDD modes||411|