3G-WCDMA

Wideband Code Division Multiple Access (WCDMA)

• WCDMA is a wideband spread-spectrum 3G mobile telecommunication air interface that utilizes code division multiple access (or CDMA the general multiplexing scheme, not to be confused with CDMA the standard). It provides simultaneous support for a wide range of services with different characteristics on a common 5MHz carrier.The term WCDMA also refers to one of the International Telecommunications Union's IMT-2000 standards, a type of 3G cellular network. WCDMA is the technology behind the 3G UMTS standard and is closely allied with the 2G GSM standard. It provides new service capabilities, increased network capacity and reduced cost for voice and data services.The term 'WCDMA Evolved' describes the evolution of WCDMA, addressing both operators' needs for efficiency and users' demands for enhanced experience and convenience. The first steps of this evolution are HSDPA and Enhanced Uplink.


• Introduction
  This paper describes the evolution of Wideband Code Division Multiple Access (WCDMA)1, which is the radio access network part of the Universal Mobile Telephony System (UMTS), the most widely deployed 3G cellular standard in the world.
  
  Section 2 briefly reviews the history of spread spectrum technology, covering the key developments of spread spectrum and CDMA in the 1950s and the early proposals of CDMA-based cellular systems in the 1980s. Note that throughout this paper, the acronym CDMA is used consistently to refer to the basic multiple access principle and not to the IS-95 family of standards, which is sometimes also referred to as “CDMA”.
  
  Section 3 focuses on the development of the successful WCDMA 3G cellular standard fromthe early 1990s up to the release of the first version of the UMTS standard in 1999.
  
  In section 4 some of the key technologies and innovations of WCDMA are exemplified. Technical challenges and requirements behind the solutions are described, noting that they were largely different from those of the older 2G standard IS-95. As a consequence, WCDMA and the IS-95 family of standards include different technical solutions.
  
  Section 5 discusses the role of the open, collaborative standardization process of mobile cellular standards, the relation to so-called “FRAND” commitments for essential patents and the importance of transparency in technology contribution.
  
  An appendix is also included, clarifying some of the basic differences between the WCDMA standard and the IS-95 family of standards, particularly those related to the air interface.
  
  
  References : http://www.ericsson.com