Spread Spectrum refers to a system originally developed for military applications, to provide secure communications by spreading the signal over a large frequency band. … These narrowband signals are easily jammed by any other signal in the same band.
What is wireless spread spectrum?
Spread spectrum is a form of wireless communications in which the frequency of the transmitted signal is deliberately varied. … First, a signal whose frequency is constant is subject to catastrophic interference. This occurs when another signal is transmitted on, or very near, the frequency of the desired signal.
What is the use of spread spectrum?
The main advantage of spread spectrum communication technique is to prevent “interference” whether it is intentional or unintentional. The signals modulated with these techniques are hard to interfere and cannot be jammed. An intruder with no official access is never allowed to crack them.
What is spread spectrum and its goal?
“In spread spectrum, we spread the bandwidth of a signal into a larger bandwidth. Spread spectrum techniques add redundancy; they spread the original spectrum needed for each station. The expanded bandwidth allows the source to wrap its message in a protective envelope for a more secure transmission.
Does WIFI use spread spectrum?
Wi-Fi uses Direct Sequence Spread Spectrum (DSSS) instead of FHSS. Its carrier does not hop or change frequency and remains centered on one channel that is 22 MHz-wide. While there is room for 11 overlapping channels in this 83 MHz-wide band, there is only room for three non-overlapping channels.
What is spread spectrum and its types?
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)
Which is better FHSS or DSSS?
DSSS is comparatively more reliable than the system of FHSS. The rate of reliability in applications is lower in FHSS. … DSSS is rather more expensive than FHSS. At a lower Mbps, like 2 Mbps, FHSS would be less costly, but generally, radio signals are used at higher Mbps, DSSS would be less expensive than FHSS.
What is jamming margin?
jamming margin: The level of interference (jamming) that a system is able to accept and still maintain a specified level of performance, such as maintain a specified bit-error ratio even though the signal-to-noise ratio is decreasing. [ From Weik ’89]
Is OFDM spread spectrum?
OFDM can also be used as a spread spectrum modulation (OFDM-SS) [3, 4, 5] wherein spectral spreading is accomplished by putting the same data on all the carriers, producing a spreading factor equal to the number of carriers.