What is difference between CDMA and WCDMA

[Garjan]

Hello

I want some information about What is CDMA and what is WCDMA and what is the Difference between them ? Can any one tell me ?

Thanks

[ABHAYK]

CDMA is a spread spectrum multiple access technique. In CDMA a locally generated code runs at a much higher rate than the data to be transmitted. Data for transmission is simply logically XOR (exclusive OR) added with the faster code.

W-CDMA is a wideband spread-spectrum mobile air interface that utilizes the direct-sequence spread spectrum method of asynchronous code division multiple access to achieve higher speeds and support more users compared to the implementation of time division multiplexing (TDMA) used by 2G GSM networks.

[Gauresh]

WCDMA (Wideband Code Division Multiple Access) is the radio access scheme used for third generation cellular systems that are being rolled out in various parts of the globe. The 3G systems to support wideband services like high-speed Internet access, video and high quality image transmission with the same quality as the fixed networks. In WCDMA systems the CDMA air interface is combined with GSM based networks. The WCDMA standard was evolved through the Third Generation Partnership Project (3GPP) which aims to ensure interoperability between different 3G networks.

[Rahul45]

WCDMA Technical features

• Radio channels are 5MHz wide.
• Chip rate of 3.84 Mcps
• Supports two basic modes of duplex: frequency division and time division. Current systems use frequency division, one frequency for uplink and one for downlink. For time division, FOMA uses sixteen slots per radio frame, whereas UMTS uses fifteen slots per radio frame.
• Employs coherent detection on both the uplink and downlink based on the use of pilot symbols and channels.
• Supports inter-cell asynchronous operation.
• Variable mission on a 10 ms frame basis.
• Multicode transmission.
• Adaptive power control based on SIR (Signal-to-Interference Ratio).
• Multiuser detection and smart antennas can be used to increase capacity and coverage.
• Multiple types of handoff (or handover) between different cells including soft handoff, softer handoff and hard handoff.

[Kirtikumar]

WCDMA is advance version of CDMA . WCDMA and CDMA both are 3G network .
In WCDMA all the good qualities of the TDMA, FDMA, and CDMA is used. In other words quality of Gsm + Cdma is used in WCDMA.

[wp9999]

Please can you tell me if the cdma and or wcdma are geographically restricted - do they both function in South Africa or only in America and other countries I know that 3G operates in South Africa.

[wp9999]

Originally Posted by Kirtikumar

WCDMA is advance version of CDMA . WCDMA and CDMA both are 3G network .
In WCDMA all the good qualities of the TDMA, FDMA, and CDMA is used. In other words quality of Gsm + Cdma is used in WCDMA.

A friend told me that CDMA is in America and not used in South Africa - is this true

[karunakar]

Vodacom is the first mobile operator in Africa to put a 3G/W-CDMA network into commercial operation from 2004 in Africa cdma exist ..

[NAVINk]

In south Africa Vodacom is a GSM 900 & W-CDMA/3G network in South Africa. and Neotel operators provides CDMA (3G - CDMA2000 1xEV-DO Rel. 0 ) service in Johannesburg, Pretoria.

[wp9999]

Thank you for the reply - I have never heard Neotel as a cellphone service provider brand - do they go by a different name or where does one find them and what do they provide - I am beginning to sell a brand of Celphones in the region and they are all GSM and CDMA (but none specifying 3G or WCDMA so I was worried that they may either not be up to scratch or worse still possibly not locally compatible (so I now gather the GSM will work with Vodacom - but is it less good than 3G?)

[jimitt007]

so can we use cdma sim card in wcdma phones.

for eg:- i m using nokia 6233 cell phone and i want to use reliance cdma sim card so can i use it in my cell phone .



plz do reply.

thanx in advance

[geethavanijayam]

can i use CDMA sim card in wcdma slot...please help me wuth this doubt!


Thanks in advance

[hanery]

WCDMA is the 3G standard used by GSM carriers, It is Direct Spread is an air interface standard found in 3G mobile telecommunications networks.
Code division multiple access (CDMA) is a channel access method used by various radio communication technologies. It is called muiltiple access because user shares the band of frequencies.