What is the importance of spreading gain in DSSS?

What is the importance of spreading gain in DSSS?

DSSS spreading gain 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. This is because the wanted signal becomes larger.

How does DSSS increase bandwidth?

DSSS technology breaks down the transmitted stream of data into small pieces across a frequency channel. A redundant bit pattern (known as a chipping code) is generated for each bit transmitted. DSSS technology uses more bandwidth than FHSS, but is considered more reliable and resists interference.

What is spread spectrum explain DSSS?

In telecommunications, direct-sequence spread spectrum (DSSS) is a spread-spectrum modulation technique primarily used to reduce overall signal interference. The direct-sequence modulation makes the transmitted signal wider in bandwidth than the information bandwidth.

How DSSS is useful in WLAN?

The IEEE 802.11b WLAN is an example of a wireless network that uses DSSS transmission. FHSS uses more powerful signals that are transmitted in a pseudo-random se- quence on several different frequencies. The receiver has to ensure that it is on the same frequency as the transmitter at exactly the same time.

What is the key advantage of DSSS?

Following are the benefits or advantages of DSSS: ➨It uses both time and frequency planes for transmission of information bits, effect of interference and fading can be minimized to great extent. ➨It can be employed in point to point applications at the rate of 11 Mbps.

Where is DSSS used?

DSSS is a spread spectrum modulation technique used for digital signal transmission over airwaves. It was originally developed for military use, and employed difficult-to-detect wideband signals to resist jamming attempts. It is also being developed for commercial purposes in local and wireless networks.

Can we share a bandwidth in DSSS?

Not spectrally efficient for one user, but DSSS also allows many users to share the same bandwidth (MAC technique).

What are the spread spectrum techniques?

There are four generic types of spread spectrum signals:

• Direct Sequence (DS) – The carrier of a DS source stays at a fixed frequency. Narrowband information is spread out into a much larger bandwidth using a pseudo-random chip sequence.
• Pseudo noise (PN)
• Frequency Hopping (FHA)
• Linear Frequency Modulation (chirp)

What are the applications of spread spectrum?

Current applications of spread spectrum technology include wireless LANs (local area networks), bar code scanners, and microphones. This technology improves the efficiency and effectiveness of business processes, many of which are finding that wireless communications are requisite for success.

What are the disadvantages of DSSS techniques?

Following are the disadvantages of DSSS: ➨It is very sensitive technology in the presence of harsh environments such as collocated cells, larger coverage areas, multipath and in the presence of frequencies used for bluetooth network. This is due to the fact that it operates at narrow bandwidth.

Why is DSSS preferred over FHSS technique for bursty data transmission?

DSSS, in contrast, spreads the signal across a wider bandwidth than FHSS, creating a lower power density across the spectrum. DSSS encodes each bit of data into 11-chip sequences, which provide both security and robustness against noise.

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.

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 ).

Which is the first part of the DSSS process?

The first part of the process is to generate the DSSS signal. Take as an example that the data to be transmitted is 1001, and the chip or spreading code is 0010.

Which is the best technique for spread spectrum?

2) Direct sequence (DS) which introduces rapid phase transition to the data to make it larger in bandwidth. We will focus on Direct Sequence Spread Spectrum technique since it is the mostly used in the industry (CDMA, UMTS, 802.11, GPS).