Although there are many different implementations of spread spectrum technology, what are the only types specified by the Federal Communications Commission (FCC) in CFR Part 15?

Although there are many different implementations of spread spectrum technology, what are the only types specified by the Federal Communications Commission (FCC) in CFR Part 15?

• A. Direct Sequencing Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).
• B. CDMA and OFDM.
• C. DSSS only.
• D. FHSS only.

Answer: (A)

Spread-spectrum implementations defined by the FCC under CFR Part 15 are two: Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum. In direct sequence spread spectrum, the data is combined with a high-rate pseudorandom code, spreading the signal across a wide bandwidth. The receiver uses the same code to despread and recover the original data. In frequency hopping spread spectrum, the carrier rapidly hops among multiple frequencies according to a pseudorandom sequence, so the energy is spread over time and frequency. Both methods are the two types specified by the regulation, which is why they’re the correct answer. CDMA is a broader concept that uses spreading but isn’t listed as a distinct spread-spectrum type in CFR Part 15, and OFDM is a modulation technique rather than a spread-spectrum type defined there.

Spread-spectrum implementations defined by the FCC under CFR Part 15 are two: Direct Sequence Spread Spectrum and Frequency Hopping Spread Spectrum.

In direct sequence spread spectrum, the data is combined with a high-rate pseudorandom code, spreading the signal across a wide bandwidth. The receiver uses the same code to despread and recover the original data. In frequency hopping spread spectrum, the carrier rapidly hops among multiple frequencies according to a pseudorandom sequence, so the energy is spread over time and frequency. Both methods are the two types specified by the regulation, which is why they’re the correct answer.

CDMA is a broader concept that uses spreading but isn’t listed as a distinct spread-spectrum type in CFR Part 15, and OFDM is a modulation technique rather than a spread-spectrum type defined there.