a. Direct sequence spread spectrum (DSSS). b. Frequency hopping spread spectrum (FHSS). c. Infrared d. Orthogonal frequency division multiplexing(OFDM)
Fast frequency hopping spread spectrum (FHSS) systems switch between frequencies rapidly, usually several times per second, to avoid interference and jamming. Slow FHSS systems switch between frequencies less frequently, providing a more predictable and stable connection but potentially making them more vulnerable to interference.
Slow frequency-hopping spread spectrum (FHSS) systems hop between frequencies at a lower rate, typically around 1-5 hops per second, while fast FHSS systems hop at a higher rate, often over 20 hops per second. The main difference lies in the speed of frequency hopping, with fast FHSS providing increased resistance to interference and higher data transmission rates compared to slow FHSS systems.
exlanation of fhss block diadram
FHSS(Frequency Hopping Spread Spectrum)
during World War II
No
FHSS- Which has been dropped recently DSSS- which is still used by access points to advertise themselves
FHSS continuously changes the center frequency of a conventional carrier several times per second according to a pseudo-random set of channels, while chirp spread spectrum changes the carrier frequency. Because a fixed frequency is not used, illegal monitoring of spread spectrum signals is extremely difficult, if not downright impossible depending on the particular method. FHSS is the transmission technology in Bluetooth. See http://www.answers.com/topic/802-11-technology, http://www.answers.com/topic/wi-fi-technology and http://www.answers.com/topic/bluetooth-technology. FHSS continuously changes the center frequency of a conventional carrier several times per second according to a pseudo-random set of channels, while chirp spread spectrum changes the carrier frequency. Because a fixed frequency is not used, illegal monitoring of spread spectrum signals is extremely difficult, if not downright impossible depending on the particular method. FHSS is the transmission technology in Bluetooth. See http://www.answers.com/topic/802-11-technology, http://www.answers.com/topic/wi-fi-technology and http://www.answers.com/topic/bluetooth-technology.
"Direct Sequence Spread Spectrum (DSSS)DSSS multiplies the data bits by a very fast pseudo-random bit pattern (PN sequence) that "spreads" the data into a large coded stream that takes the full bandwidth of the channel. DSSS is the basis for CDMA cellphones and 802.11 Wi-Fi wireless transmission. For a technical example of DSSS technology, see cdma.Frequency Hopping Spread Spectrum (FHSS)FHSS continuously changes the center frequency of a conventional carrier several times per second according to a pseudo-random set of channels, while chirp spread spectrum changes the carrier frequency. Because a fixed frequency is not used, illegal monitoring of spread spectrum signals is extremely difficult, if not downright impossible depending on the particular method. FHSS is the transmission technology in Bluetooth. See integrated-business-systems-and-services-inc, wifiand bluetooth."From spread-spectrum
"Direct Sequence Spread Spectrum (DSSS)DSSS multiplies the data bits by a very fast pseudo-random bit pattern (PN sequence) that "spreads" the data into a large coded stream that takes the full bandwidth of the channel. DSSS is the basis for CDMA cellphones and 802.11 Wi-Fi wireless transmission. For a technical example of DSSS technology, see cdma.Frequency Hopping Spread Spectrum (FHSS)FHSS continuously changes the center frequency of a conventional carrier several times per second according to a pseudo-random set of channels, while chirp spread spectrum changes the carrier frequency. Because a fixed frequency is not used, illegal monitoring of spread spectrum signals is extremely difficult, if not downright impossible depending on the particular method. FHSS is the transmission technology in Bluetooth. See integrated-business-systems-and-services-inc, wifiand bluetooth."From spread-spectrum
It can't, Prof. Schiller is wrong In contrary DSSS is more vulnerable to multipathing than e.g. FHSS is since it could just ignore its own shadows after jumping.