Which wireless technology divides data streams and encodes them into small chunks called chips, which are spread over all available frequencies at the same time?

Which wireless technology divides data streams and encodes them into small chunks called chips, which are spread over all available frequencies at the same time?

• A. DSSS (Direct Sequence Spread Spectrum)
• B. FHSS (Frequency Hopping Spread Spectrum)
• C. Omnidirectional sequence
• D. CDMA (Code Division Multiple Access)

Answer: (C)

Direct Sequence Spread Spectrum is being described. In this approach, the data stream is converted into a stream of chips by multiplying it with a high-rate pseudorandom code. Those chips spread the signal across a wide bandwidth, so energy fills many frequencies at once rather than staying in a narrow band. At the receiver, the same pseudorandom code is used to correlate and recover the original data, providing resilience to interference and enabling multiple users to share the spectrum. This is different from frequency hopping spread spectrum, which spreads the signal by hopping among frequencies over time rather than occupying them all simultaneously. Omnidirectional sequence isn’t a standard term for this concept, and while CDMA uses spreading codes to allow multiple users, the description here matches the spreading process itself, i.e., Direct Sequence Spread Spectrum.

Direct Sequence Spread Spectrum is being described. In this approach, the data stream is converted into a stream of chips by multiplying it with a high-rate pseudorandom code. Those chips spread the signal across a wide bandwidth, so energy fills many frequencies at once rather than staying in a narrow band. At the receiver, the same pseudorandom code is used to correlate and recover the original data, providing resilience to interference and enabling multiple users to share the spectrum. This is different from frequency hopping spread spectrum, which spreads the signal by hopping among frequencies over time rather than occupying them all simultaneously. Omnidirectional sequence isn’t a standard term for this concept, and while CDMA uses spreading codes to allow multiple users, the description here matches the spreading process itself, i.e., Direct Sequence Spread Spectrum.