Difference Between FHSS and DSSS

FHSS (Frequency Hopping Spread Spectrum) and DSSS (Direct Sequence Spread Spectrum) are two different wireless data transmission methods that fall under the spread spectrum communication umbrella. While both FHSS and DSSS can be used to improve the security and reliability of wireless transmissions, they have significant differences.

Read this article to find out more about FHSS and DSSS and how they are different from each other.

What is FHSS?

FHSS, or Frequency Hopping Spread Spectrum, is a wireless data transmission method that involves constantly changing the frequency of the transmitted signal across a wide frequency range. This is accomplished by segmenting the frequency spectrum into multiple channels and rapidly switching between them at regular intervals. The transmitter and receiver are synchronized so that they both know which frequency is currently in use. FHSS signals cause little interference in narrowband communications and vice versa.

FHSS's frequency hopping pattern is typically pseudorandom, which means it appears random but is actually determined by a mathematical algorithm. This reduces the possibility of unauthorized users intercepting or jamming the signal. It is used in different applications such as wireless LANs, wireless sensors, and military communications.

FHSS allows multiple users to share the same frequency band without interfering with each other. FHSS can make the best use of the available spectrum by using a different frequency channel for each transmission. FHSS adds a layer of security by making it difficult for unauthorized parties to intercept the signal.

FHSS can operate in high-interference environments, such as those in industrial settings or densely populated urban areas. FHSS can avoid interference from other wireless devices running in the same frequency band by rapidly switching between frequency channels.

What is DSSS?

DSSS, or Direct Sequence Spread Spectrum, is a wireless data transmission method that involves spreading the signal across a wide range of frequencies using a spreading code. Before transmission, the spreading code is combined with the data signal, and the receiver uses the same code to extract the original data signal.

The DSSS spreading code is typically a long, complex sequence of 1s and 0s generated by a mathematical algorithm. This sequence is combined with the original data signal via a process known as "chipping," which involves multiplying each bit of the data signal by a corresponding bit from the spreading code. This method effectively spreads the signal across a wide frequency range, making it more resistant to interference and noise.

The spreading code is used at the receiver to "de-chip" the signal and extract the original data signal. The receiver must be synchronized with the transmitter at all times so that it knows which spreading code is being used.

The ability of DSSS to tolerate interference and noise is one of its advantages. Because the signal spans a wide frequency range, it is less susceptible to interference from other wireless devices or sources of electromagnetic noise. Furthermore, because the original data signal is reconstructed from multiple bits of the spreading code, some parts of the signal can be lost while the overall transmission remains unaffected.

Difference between FHSS and DSSS

The following table highlights the major differences between FHSS and DSSS −




Signal Transmission Speed

FHSS signal transmission speed is slow.

DSSS signal transmission speed is high.

Size of Network

The size of the FHSS network is small to medium.

Size of DSSS network is large


Less Expensive

More Expensive


Complexity is less

Complexity is More


Less reliable

More reliable


FHSS is suitable for single- point and multipoint communications.

DSSS is suitable for point- to-point communications.

Rate of Signal Transmission

The FHSS signal transmission rate is 3 Mbps.

The DSSS signal transmission rate is 11 Mbps.


Frequency-hopping spread spectrum

Direct-Sequence Spread Spectrum


It is used in military and industrial applications.

It is used in consumer applications such as wireless LANs, GPS, and Bluetooth.


In conclusion, both FHSS and DSSS are spread-spectrum wireless communication techniques, but they differ in how the signal is spread across the frequency spectrum. FHSS spreads the signal over a wide range of frequencies using frequency hopping, whereas DSSS spreads the signal using a code to reconstruct the original data signal.

FHSS is commonly used in high-security applications such as military communications, whereas DSSS is used in wireless LANs and Bluetooth devices due to its ability to tolerate interference and noise. Understanding the distinctions between FHSS and DSSS is critical for determining the best method for specific wireless communication applications.

Updated on: 03-Apr-2023

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