Introduction: Challenges in Wireless Communication and the Need for Spread Spectrum Techniques
Modern wireless communication environments face constant jamming attempts and security threats. To counter these threats, spread spectrum techniques are essential for ensuring the stability and security of wireless communications. FHSS (Frequency Hopping Spread Spectrum) and DSSS (Direct Sequence Spread Spectrum) are representative spread spectrum technologies, each spreading the transmission signal in a unique way to increase resistance to jamming and make signal detection difficult. This post aims to help readers understand the core principles of FHSS and DSSS by examining the latest trends and practical applications.
Core Concepts and Principles: FHSS and DSSS
Spread spectrum technology intentionally broadens the bandwidth of a signal to reduce power density. This reduces the impact of jamming signals and effectively hides the signal itself. FHSS and DSSS are leading methods for implementing this spread spectrum.
FHSS (Frequency Hopping Spread Spectrum)
FHSS is a method of transmitting data while rapidly changing frequencies according to a predetermined pattern. The transmitter and receiver share the same frequency hopping sequence, using a specific frequency to transmit data for a short period before moving to the next frequency. This way, even if a jamming signal is concentrated on a specific frequency, FHSS can minimize the impact of jamming by quickly changing frequencies. According to 「Industrial frequency bands available without prior permission - GilliLab - TechLog (2025. 7. 3.)」, FHSS is a spread spectrum method that transmits by changing the frequency over time instead of fixing it.
DSSS (Direct Sequence Spread Spectrum)
DSSS broadens the bandwidth by multiplying the data signal to be transmitted by a long pseudo-random bit sequence called a 'chip.' The receiver uses the same chip sequence to restore the original data. DSSS not only increases resistance to jamming by reducing the power density of the signal but also allows multiple users to share the same frequency band in Code Division Multiple Access (CDMA) systems. According to 「Low Probability of Intercept Radar Technology and Survivability Enhancement in the Electronic Warfare Era (2025. 9. 30.)」, DSSS is effective for bandwidth expansion, power density reduction, and the generation of noise-like signals.
Latest Trends and Changes
Recent trends in wireless communication technology focus on further developing FHSS and DSSS and applying them to various fields. The Global Trends 2025 report analyzes the impact of wireless communication technologies, including FHSS and DSSS, on global development. In addition, LR-FHSS-based technology is increasingly being applied to satellite IoT communication to provide robustness against interference. Research comparing and analyzing the security performance of DSSS and FHSS in underwater acoustic channels is also actively underway.
Practical Application Methods
FHSS and DSSS are used in various practical environments. Diversity technology is a core technology for responding to wireless communication fading and utilizes both DSSS and FHSS methods. Stable communication can be implemented through FHSS and DSSS in wireless communication between drones and users, low-power wireless devices, and IoT devices. In particular, the technical standards for wireless equipment for wireless stations that can be established without notification under Article 45 of the 「Radio Act」 and Article 19 of the 「Radio Equipment Rules」 were revised on March 27, 2025, making it easier to build wireless communication systems using FHSS and DSSS technologies under specific conditions.
Expert Advice
💡 Technical Insight
Precautions When Introducing Technology: Before applying FHSS and DSSS to a real system, it is necessary to clearly understand the advantages and disadvantages of the technology and sufficiently verify its performance in a specific environment. In particular, frequency hopping sequence design, chip sequence selection, and synchronization method have a significant impact on system performance and should be carefully considered. It is also important to comply with related regulations and standards. 「The IEEE 802.11 standard is officially abolished when integrated into the latest version but tends to be used for marketing.」
Outlook for the Next 3-5 Years: FHSS and DSSS are expected to remain core technologies in wireless communication systems. In particular, the importance of FHSS and DSSS will increase in fields where wireless communication is essential, such as IoT, drones, and autonomous vehicles. In addition, research is expected to actively optimize the performance of FHSS and DSSS using Artificial Intelligence (AI) technology.
Conclusion
FHSS and DSSS are essential spread spectrum technologies for anti-jamming and security enhancement in wireless communication environments. FHSS minimizes the impact of jamming by quickly changing frequencies, and DSSS increases resistance to jamming by reducing the power density of the signal. Recent trends focus on further developing these technologies and applying them to various fields. The importance of FHSS and DSSS is expected to increase in fields where wireless communication is essential, such as IoT, drones, and autonomous vehicles. When introducing technology, it is important to clearly understand the advantages and disadvantages and comply with related regulations and standards.