UMTS vs. W-CDMA
Universal Mobil Telecommunications System (also known as UMTS) is a third generation (or 3G) telecommunications technology for mobile electronics. The most common form of UMTS makes use of W-CDMA (Wideband Code Division Multiple Access, which is an air interface standard that is a compulsory feature of any mobile telecommunications device of the 3G network). However, the system makes use of TD-CDMA (Time Division CDMA) and TD-SCDMA (Time Division Synchronous CDMA). UMTS is a complete network system. As such it also covers the radio access network, the core network, and the authentication of users using the USIM cards (or Subscriber Identity Module).
W-CDMA is an air interface standard that is most notably found in 3G mobile telecommunications networks. It is the most widely used member of the UMTS family and is, in fact, often times used synonymously for UMTS. It makes use of the DS-CDMA channel access method as well as the FDD duplexing method in order to achieve higher speeds and to also support more users –in comparison to most of the time division multiple access schemes (or TDMA). It uses the same basic network that is found in the 2G GSM networks. This enables dual mode operation as well as with the GSM/EDGE –another trait it shares in common with other members of the UMTS family.
UMTS requires the use of new base stations as well as new frequency allocations. Despite these restrictions, however, UMTS is closely related to GSM (that is Global System for Mobile Communications, the most popular standard for mobile communication technology) and builds upon the concepts of GSM –most UTMS handsets support GSM in order to allow dual mode operation without any issues.
W-CDMA includes a plethora of key features. These features include, but are not limited to, radio channels that are 5 MHz wide, a chip rate of 3.84 Mcps, variable mission on a 10 ms frame basis, multicode transmission, adaptive power control based on the Signal to Interference Ratio (or SIR), multiuser detection as well as smart antennae (which can be used to increase the capacity and coverage of the device), and multiple types of handoff (or handover) between different calls (which include soft handoff, softer handoff, and hard handoff).
Summary:
1. UMTS is a 3G telecommunications technology that makes use of the W-CDMA as well as other permutations therein; W-CDMA is an air interface standard found in 3G mobile telecommunications networks and is a member of the UMTS family.
2. UMTS requires new base station and frequency allocations to thrive; W-CDMA makes use of the DS-CDMA channel access method as well as the FDD duplexing method to achieve higher speeds and support more users.
3. UMTS has a theoretical transfer speed of 21 Mbit/s; W-DCMA includes radio channels that are 5MHz wide and a chip rate of Mcps.