7 April 2018

What is frequency hopping spread spectrum

Frequency hopping spread spectrum is a method of transmitting radio signals by rapidly switching a carrier.  

In FHSS among many frequency channels using pseudorandom sequence known to both transmitter and receiver. 

Overview :

In FHSS the data bits that are transmitted in the different frequency slots are changed by the PN sequence.

FHSS is often used as a method to allow multiple transmitter and receiver pairs, it can operate in the same space on he same broad channel at the same time.

In FHSS the data sequence is spread over small frequency slots of the spread spectrum signal.

FHSS is a wireless technology that spreads its signal over rapidly changing frequencies. 

Advantages and disadvantages :

The advantages of Frequency hopping spread spectrum given below :
  • It has less distance effect.
  • Provide greatest amount of spreading.
  • The bandwidth of these system is large.
  • It has a short acquisition time.
  • Best discrimination against multi-path.
  • Very large bandwidth.
  • The synchronization is not greatly dependent on distance.
  • It can be programmed to avoid some part of the spectrum.
Disadvantages of Frequency hopping spread spectrum given below :
  • It needs complex and costly digital frequency synthesizers are required to be used.
  • It need error detection.
  • The processing gain is higher than that of direct sequence spread spectrum.
  • It is not useful for range and range rate measurement.
Application :
  • Wireless local area network standard for Wi-Fi.
  • Military communication equipment.
  • Wireless personal area network standard for bluetooth.