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I think OFDMA is used for cellphone communications via satellites. As far as I know, it is the best technique available which addresses all challenges like multipath fading, error correction, effective bandwidth utilization, security issues etc.
Here, harmonics of a base carrier are considered for modulation. These signals will be orthogonal to each other. Hence can be overlapped on each other for transmission, without the signals getting collided. If we use N such orthogonal carriers, the BW requirement will be N times lesser than the classical modulation schemes (such as ASK, BPSK etc.)
Practically, using N signal generators to produce precise orthogonal signals is difficult. Hence we do this in digital domain, where IFFT operation performs the same. (producing & adding orthoganal carrier signals).
I'm Shreyas. Setting up an OFDM based Tx-Rx model was my academic project during my bachelor studies under Telecommunications.
Hope I have answered in a simple way, with enough details :)
Wiki User
∙ 11y ago
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∙ 14y agoofdm
ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING
Wiki User
∙ 9y agoIn CDMA technology, a spread-spectrum modulation is utilized. CDMA stands for code division multiple access, and it has been around since the 1930s.
Wiki User
∙ 12y agoGMSK is used in GSM and QAM is used for CDMA
Wiki User
∙ 11y agoQPSK and 16PSK
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What type of antenna is used in gsm and CDMA?
http://www.ehow.com/list_7279317_types-gsm-antennas.html
Is same CDMA sim can be changed to gsm sim?
Type your answer here... can v chande a cdma sim to gsm
Is CDMA better or gsm to be used in egypt?
does cdma work in egypt
Can you put the CDMA sim card to the gsm phone?
CDMA and GSM are Radio technologies and mobile Phone is just an Antenna to receive these Radio Signals. Since both the technologies work on different frequency range and has different modulation shemes therfore the mobile phones for both are different.Apart from this 3G tehchnology which is combination of both GSM and CDMA (WCDMA) is compatible with both GSM and CDMA. So a 3G mobile can serve for both GSM and CDMA radio signals.SIM (Subcriber Idendity Module) is consists of Credential for network authorization. Since Both GSM and CDMA technologies has different Authorization functions and parameters hence both SIMs are different. Note: In CDMA technology SIM is often called as RUIM (Removable User Idendity Module).CDMA uses Different Frequencies than GSM. CDMA also does not require a SIM card.Now some companies do provide SIM cards for CDMA connections also, such as Reliance communications and TATA Indicomm in India.CDMA can hold more calls per channel on their towers, while GSM drops alot of calls. That is why people are always complaining about T-Mobile and At&t dropped calls. GSM is used internationally while CDMA is mostly used in the domestic United States. CDMA carriers are Verizon, Alltel, Sprint, Cricket....while GSM carriers here in the U.S. are T-Mobile and At&t.
What use is CDMA in mobile?
CDMA is a type of network that cell phone company's use. There are to meager types of networks that are used CDMA and GSM. Cell phone are usally made to work on one or the other network. The Iphone is GSM and Verizons Dare is CDMA but some phone can work on both like the new Blackberry storm.
Can MNP be applied from CDMA to gsm?
yes you can change gsm to cdma via mnp.
Vietnam use gsm or CDMA?
gsm
Which is best CDMA or gsm?
CDMA, offers better data transfer
What is gsm or CDMA?
GSM = Global System for Mobile communications. CDMA = Code Division Multiple Access.
What if operating frequency for CDMA network in yemen?
cdma gsm
Is Smart Philippines GSM or CDMA carrier?
Gsm
Is Smart Philippines a GSM or CDMA carrier?
It's a gsm/umts network. There's no cdma carrier in the Philippines.
