Editing UMTS (section)

==== Development ====
In the late 1990s, W-CDMA was developed by NTT DoCoMo as the air interface for their 3G network [[FOMA]]. Later NTT DoCoMo submitted the specification to the [[International Telecommunication Union]] (ITU) as a candidate for the international 3G standard known as IMT-2000. The ITU eventually accepted W-CDMA as part of the IMT-2000 family of 3G standards, as an alternative to CDMA2000, EDGE, and the short range [[DECT]] system. Later, W-CDMA was selected as an air interface for [[UMTS frequency bands|UMTS]].

As NTT DoCoMo did not wait for the finalisation of the 3G Release 99 specification, their network was initially incompatible with UMTS.<ref>{{citation|author=Hsiao-Hwa Chen|title=The Next Generation CDMA Technologies|publisher=John Wiley and Sons|year=2007|isbn=978-0-470-02294-8|pages=105–106}}</ref> However, this has been resolved by NTT DoCoMo updating their network.

Code-Division Multiple Access communication networks have been developed by a number of companies over the years, but development of cell-phone networks based on CDMA (prior to W-CDMA) was dominated by [[Qualcomm]], the first company to succeed in developing a practical and cost-effective CDMA implementation for consumer cell phones and its early [[cdmaOne|IS-95]] air interface standard has evolved into the current CDMA2000 (IS-856/IS-2000) standard. Qualcomm created an experimental wideband CDMA system called CDMA2000 3x which unified the W-CDMA ([[3rd Generation Partnership Project|3GPP]]) and CDMA2000 ([[3rd Generation Partnership Project 2|3GPP2]]) network technologies into a single design for a worldwide standard air interface. Compatibility with CDMA2000 would have beneficially enabled roaming on existing networks beyond Japan, since Qualcomm CDMA2000 networks are widely deployed, especially in the Americas, with coverage in 58 countries {{as of|2006|lc=on}}. However, divergent requirements resulted in the W-CDMA standard being retained and deployed globally. W-CDMA has then become the dominant technology with 457 commercial networks in 178 countries as of April 2012.<ref>{{cite web|url=http://www.gsacom.com/downloads/pdf/HSPA_operator_commitments_160412.php4|title=GSM Association HSPA Market update April 2012}}</ref> Several CDMA2000 operators have even converted their networks to W-CDMA for international roaming compatibility and smooth upgrade path to [[LTE (telecommunication)|LTE]].

Despite incompatibility with existing air-interface standards, late introduction and the high upgrade cost of deploying an all-new transmitter technology, W-CDMA has become the dominant standard.