What is direct sequence spread spectrum technology?

Glossary Term: Direct-Sequence Spread Spectrum Direct-Sequence Spread Spectrum: A transmission technology used in WLAN (wireless LAN) transmissions where a data signal at the sending station is combined with a higher data-rate bit sequence, or chipping code, that divides the user data according to a spreading ratio.

How does DSSS work in CDMA technology?

Our method uses DS-CDMA based on direct-sequence spread spectrum (DSSS). The method is physical layer and a multiple-access technique (i.e., the code division multiple channel access technique) to divide the channel into subchannels, and transmits data through these subchannels.

Does CDMA use DSSS?

DS-CDMA (Direct-Sequence Code Division Multiple Access) is a multiple access scheme based on DSSS, by spreading the signals from/to different users with different codes.

Is CDMA a spread spectrum?

In Code Division Multiple Access (CDMA) systems all users transmit in the same bandwidth simultaneously. Communication systems following this concept are “spread spectrum systems”. In this transmission technique, the frequency spectrum of a data-signal is spread using a code uncorrelated with that signal.

Is CDMA and DSSS same?

Direct sequence spread spectrum (DSSS) transmission employs a chipping code to “spread” the transmission over a wider frequency band than it would normally occupy. DSSS is a form of CDMA (see Chapter 4). But instead of a pseudorandom binary sequence (PRBS), an 11-bit Barker code is used as the spreading sequence.

How does CDMA technology work?

How Does CDMA Work? CDMA allows up to 61 concurrent users in a 1.2288 MHz channel by processing each voice packet with two PN codes. In fact, many different “signals” baseband with different spreading codes can be modulated on the same carrier to allow many different users to be supported.

What is the advantage of CDMA?

One of the main advantages of CDMA is that dropouts occur only when the phone is at least twice as far from the base station. Thus it is used in the rural areas where GSM cannot cover. Another advantage is its capacity; it has a very high spectral capacity that it can accommodate more users per MHz of bandwidth.

What is a good code for CDMA?

Ideal codes for CDMA should have delta function as their autocorrelation functions, and 0 for cross-correlation functions, i.e., autocorrelation function \rho(\tau) = \delta(\tau). cross-correlation functions \rho_{i,j}(\tau)=0, for all i \neq j, for all \tau.

Is DSSS and CDMA same?

Which modulation is the most efficient?

6. Which modulation is the most efficient one? Explanation: Of all the modulation showed, QAM is the most bandwidth efficient one.

How does direct sequence spread spectrum ( DSSS ) work?

Michael Adams, in Modern Cable Television Technology (Second Edition), 2004 Direct sequence spread spectrum (DSSS) transmission employs a chipping code to “spread” the transmission over a wider frequency band than it would normally occupy. DSSS is a form of CDMA (see Chapter 4 ).

How is the spreading gain of DSSS defined?

If the bandwidth of the DSSS, direct sequence spread spectrum signal is W and the input data bit length or period 1/R then the DSSS spreading gain can be defined: It is found that the larger the spreading gain of the direct sequence spread spectrum signal, the more effective the performance of the system is.

What are the key elements of CDMA technology?

Key elements of CDMA. CDMA is a form of spread spectrum transmission technology based around a scheme called direct sequence spread spectrum. Direct sequence spread spectrum, DSSS is a form of radio transmission used in a variety of radio transmissions.

Which is the spreading sequence in direct sequence?

But instead of a pseudorandom binary sequence (PRBS), an 11-bit Barker code is used as the spreading sequence.

What is direct sequence spread spectrum technology? Glossary Term: Direct-Sequence Spread Spectrum Direct-Sequence Spread Spectrum: A transmission technology used in WLAN (wireless LAN) transmissions where a data signal at the sending station is combined with a higher data-rate bit sequence, or chipping code, that divides the user data according to a spreading ratio. How does…