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what is the different between cdma and wcdma

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beta_group

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difference of cdma and wcdma

hi all,
any one know what is the different between cdma and wcdma " in designing & planning"
and thanks.
 

gam

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what is wcdma

CDMA uses 1.25 MHz carrier bandwidth
WCDMa uses 5 MHz carrier bandwidth

the difference would be in the system capacity which is uch better in WCDMA than in CDMA if u're comparing the same services. However this capacity enhancement is also used to provide higher data rat services that are not possible to offer on CDMA like packet data of 384 Kbps
in addition with the new HSDPA technology on WCDMA u can reach 7.2 Mbps per user with today's handsets.
 

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muralicrl

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difference between wcdma and gsm in capacity?

Hi,

Most 3G handsets these days are dual-mode, that is, WCDMA and GSM capable. The first ones, ie the ones at 3 in Australia were only WCDMA, but the newest are all dual-mode. That means, when moving from an area of WCDMA coverage, to one without WCDMA coverage, the call will continue on the GSM network.
The biggest difference between WCDMA and CDMA2000 is the origin. WCDMA is an evolution of GSM, while CDMA2000 is an evolution of CDMA.
WCDMA uses a broader spectrum and the signalling is based on GSM. CDMA's signalling is somewhat related to TDMA signalling.
Both use Code Division to get the packets in sequence and both offer similar data speed and voice capabilities.
WCDMA handsets use an extended SIM, called a USIM (UMTS Subscriber Information Module) which contains additional WCDMA information.
 

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salma ali bakr

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differences between cdma, wcdma and gsm

WCDMA is the evolution of GSM...it uses a broader spectrum and the signalling is based on GSM...

i know some of the similarities are: data modulation (they both use QPSK)....variable spreading...convolutional coding....
 

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nalino

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different of cdma,gsm,wcdma,

CDMA and GSM are basically different as GSM uses TDMA where each user is allocated with a time certain time slot out of 8-time slots. So the time axis is sub-divided and allocated to users. When one user's slot is on, other user signals are off.

However, in CDMA users are seperate by codes not in time. These codes are user specific and prefered to be orhtogonal to seperate them from other users.
 

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throughput wcdma 5mhz

thanks for all,
but for planning when we need find the number of BTS and when we used ones of modl as hata or other what the different .
 

darock

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difference between cdma and wcdma planning

actually why do you guys call wcdma to be an evolution of gsm..there is a big difference in the multiple access..in gsm a user's bw is in the order of say 20khz. But in WCDMA its in the order of MHz..am i right?
 

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gam

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difference between cdma&wcdma

planning for WCDMA and CDMA is a complex process as u must take coverage and capacity into account in an interative process. most BTS vendors have tools to calculate this, if u want a simplistic "coverage only" approach u can prepare link budgets (one for each service like speech, Cs64, PS 384 and so on) decide what your limiting service will be and usd the cell range resulting to calculate the number of sites needed, nut again this is a very rough calculation.

WCDMA is considered evolution of GSM in standardisation point of view, they are both belonging to the 3GPP. CDMA 2000 is an evolution of the IS-95 CDMA under the 3GPP2 organization.

GSM is a completely different technology from WCDMA but the standardization body is the same. byt he way GSM channels are 200 KHz wide, WCDMA channels are 5 MHz wide.
 

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similarities between wcdma and cdma

thanks gam,
but if i want to calculate the capacity of CDMA2000 how to calculate the throughput for PDS ?
 

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differnces between n-cdma and w-cdma

North American CDMA
(cdmaOne)

�� Code Division Multiple Access
0 all users share same frequency band
0 discussed in detail later as CDMA is basis for 3G
�� Qualcomm demo in 1989
0 claimed improved capacity & simplified planning
�� First deployment in Hong Kong late 1994
�� Major success in Korea (1M subs by 1996)
�� Used by Verizon and Sprint in US
�� Simplest 3G migration story today


W-CDMA (UMTS) Pros and Cons
�� Wideband CDMA
0 Standard for Universal Mobile Telephone Service
(UMTS)
�� Committed standard for Europe and likely
migration path for other GSM operators
0 leverages GSM’s dominant position
�� Requires substantial new spectrum
0 5 MHz each way (symmetric)
�� Legally mandated in Europe and elsewhere
�� Sales of new spectrum completed in Europe
0 at prices that now seem exorbitant
 

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