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a.) CDMA and FDMA
CDMA
Same frequency is used by every user and simultaneous transmission occurs
Every narrowband signal is multiplied by wideband spreading signal, usually known as codeword
Every user has a separate pseudo-codeword, i.e., orthogonal to others
Only the desired codeword is detected by the receivers and others appear as noise
It is mandatory for the receivers to know about the transmitter's codeword
FDMA
When the channel is not in use, it sits simply idle
Bandwidth of Channel is relatively narrow (30 KHz), known as narrowband system
Little or no equalization is needed for spreading symbol time
Analog links are suitable for FDMA
Framing or synchronization bits are not needed for continuous transmission
Tight filtering is needed to minimize interference
Combined with FDD for duplexing
b.) CDMA and TDMA
CDMA
Power limited system
While people talking, random noise band playing occurs
Conversation need to be extracted from the background din
GP is high when people speak different languages, which is easier to distinguish individual speakers
It is difficult for distinguishing individuals, when GP is low.
The system performance will be degraded for every user when the number of users increases.
Fading would be reduced with wide frequency spectrum
Need to have separate multipath signals with different delays by "chip" unit.
TDMA
Receiving or transmission is allowed for only one user in a given slot
All slots are assigned cyclically
The transmission is non-continuous
It is essential to use digital data and modulation
Data rate overhead is between 20% - 30%
Overhead tradeoffs are size of data payload and latency
Multiple users are shared with single carrier frequency
Handoff is made simpler by using non-continuous transmission
All slots are assigned on demand
Due to reduced inter user interference, the power control is less stringent
What else can I help you with?
What is the difference between frequency division multiplexing and freq division multiple access?
The basic difference between fdm and fdma is that fdm is used in wired system where as fdma is used in wireless communication.
What is the applications of common source amplifier?
applications of common source amplifier
What are the applications of a monostable multivibrator?
applications of monostable multivibratorA monostable is a circuit that will respond to a stimuli only once and only for a period. Its usage can be many depends of applications
What are the advanced applications of DC series motors?
what are the advanced applications of dc series motor
What are the Applications of acceptor circuit?
There are many applications of this acceptor circuit. You can learn more about them with some electrical training programs.
What is da-fdma?
da-fdma
What is the basic difference between ofdma and sc-fdma?
The basic difference between OFDMA and SC-FDMA is that, there there is an additional block of N point DFT before the sub-channel mapping in SC-FDMA. This will effectively reduce the PAPR, thus the power amplifier will have a lesser linear range in SC-FDMA when compared with OFDMA
Why is TDMA better than FDMA?
In CDMA all the stations can sends data simultaneously. But in FDMA only one channel occupies the entire bandwidth of the link so each channel can be assigned to only one user at a time. So CDMA is better than FDMA.
What is the technology behind CDMA and gsm?
tdma and fdma
What is the difference between frequency division multiplexing and freq division multiple access?
The basic difference between fdm and fdma is that fdm is used in wired system where as fdma is used in wireless communication.
Why guard bands are required in FDMA?
to avoid the interference from one system to other system
The multiple satellite access system which suffers from the presence of intermodulation products in tdmaorfdmaorcdmaordama from these four what was the correct answer?
My guess is that fdma is the one that suffers most from intermod. I could be wrong.
What has the author Roy Stehle written?
Roy Stehle has written: 'Alternative packet switch architectures for a 30/20 GHz FDMA/TDMA geostationary communication satellite network'
What has the author John Kiesling written?
John Kiesling has written: 'Study of advanced communications satellite systems based on SS-FDMA' -- subject(s): Artificial satellites in telecommunication, Earth stations (Satellite telecommunication)
What is the difference between CDMA and FDMA?
TDMA provides many users to access the same frequency channel but different time slots. In FDMA provides many users can be used different frequency channel but at same time. circuit board
What is the difference between 1G 2G 3G generations of wireless communication?
1G is based on frequency modulation,analog technology,TDMA 2G is based on digital technology,FDMA 3G is based on CDMA which is a faster internet access source
What type of multiple access service used in satellite?
In satellite communications, the most common multiple access techniques are Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), and Code Division Multiple Access (CDMA). TDMA allocates time slots for different users to transmit their signals, while FDMA assigns specific frequency bands to each user. CDMA uses unique codes to allow multiple users to share the same frequency band simultaneously. Each technique has its advantages and is chosen based on the specific requirements of the satellite communication system.
