What type of modulation is used for DSSS?

What type of modulation is used for DSSS?

With DSSS, the message bits are modulated by a pseudorandom bit sequence known as a spreading sequence.

How are signals transmitted in DSSS?

Direct Sequence Spread Spectrum (DSSS) is a spread spectrum technique whereby the original data signal is multiplied with a pseudo random noise spreading code. This spreading code has a higher chip rate (this the bitrate of the code), which results in a wideband time continiuous scrambled signal.

How do you calculate DSSS processing gain?

The higher the processing gain of the DSSS waveform the more the resistance to interference of the DSSS signal. The classical definition of processing gain is the 10 Log number [rC/rB] in dB. By this definition a system that has a data rate of 1MBPS and a chip rate (rate of PN code) of 1MCPS will have a PG of 10.41dB.

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.

How are bits transmitted using DSSS?

Wireless Networks With DSSS, the data is divided and simultaneously transmitted on as many frequencies as possible within a particular frequency band (the channel). DSSS adds redundant bits of data known as chips to the data to represent binary 0s or 1s.

What is a chip in DSSS?

In digital communications, a chip is a pulse of a direct-sequence spread spectrum (DSSS) code, such as a pseudo-random noise (PN) code sequence used in direct-sequence code-division multiple access (CDMA) channel access techniques.

What is DSSS BPSK?

Direct Sequence Spread Spectrum (DSSS) using BPSK modulation, so the first reversing switch introduces 180 degree phase reversals according to a pseudo-random code, while the second introduces the same reversals to reconstitute the original, narrow-band signal. The output is a “recompressed” narrow-band signal.

Which filter is used to get the final FHSS and DSSS signal?

Band pass filter
Which filter is used to get the final FHSS signal? Explanation: Band pass filter is used to block difference frequency and allow the sum frequency to yield final FHSS signal.

What is the relationship between DSSS and CDMA?

CDMA used the property of DSSS that unless the transmitter and receiver used the same spreading code for both ends of the process, the signal could not be decoded and in this way it was able to provide a means of enabling a variety of different users to use the same channel to access a base station without mutual …

What is the difference between DSSS and FHSS?

The DSSS method of modulation has a higher rate of transmission than the FHSS method. The implementation of DSSS at radio frequencies with a high transmission rate costs less than implementing FHSS. At a given transmitting power, FHSS offers higher power spectral density than DSSS.

What is the difference between DSSS and CDMA?

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.

What are disadvantages of DSSS?

Disadvantages of DS/SS :

• DS/SS has a longer acquisition time.
• It require wideband channel with small phase distortion.
• The pseudo noise generator must generate sequence at high rates.
• Near-far problem.
• Fast code generator needed.
• The system is prone to error at lower than frequency hoping spread spectrum.

How can DSSS systems benefit from multipath propagation?

(c) How can DSSS systems benefit from multi-path propagation? (3 points) DSSS systems typically use rake receivers that recombine signals travelling along the different paths. Recombina- tion results in a stronger signal compared to the strongest signal only.

Which is better DSSS or FHSS?

The DSSS method of modulation has a higher rate of transmission than the FHSS method. In terms of the signal transmission rate, DSSS is superior. However, DSSS is vulnerable to electromagnetic interference and noise produced by devices operating at the same frequency band.