Wireless Communications & Mobile Technologies Flashcards

What is 'spectrum refarming' in the context of mobile networks?

Answer: Repurposing legacy spectrum bands (e.g., 2G/3G) for newer technologies like 4G/5G

Spectrum refarming involves reallocating frequency bands previously used by older technologies (such as 2G GSM) to newer, more efficient technologies like LTE or 5G NR.

Which metric measures the ratio of useful signal power to total interference plus noise power in a wireless link?

Answer: SINR (Signal-to-Interference-plus-Noise Ratio)

SINR quantifies link quality by comparing desired signal power against the combined interference from other sources and background noise.

What is the key characteristic of a 'small cell' compared to a macrocell tower?

Answer: Small cells have lower transmit power and shorter range, used to boost capacity in dense areas

Small cells (picocells, femtocells, microcells) use low power over short distances to add network capacity in dense urban or indoor areas.

What does 'beamforming' enable in 5G massive MIMO systems?

Answer: Redirecting radio energy toward specific users instead of broadcasting in all directions

Beamforming focuses radio signals toward individual users by adjusting antenna phase and amplitude, improving signal strength and reducing interference.

Which US regulatory body is responsible for licensing and regulating wireless spectrum?

Answer: NTIA (National Telecommunications and Information Administration) for federal use; FCC for commercial use

The FCC manages commercial and non-federal spectrum, while NTIA manages federal government spectrum use in the United States.

What is the primary technical difference between HSPA+ and LTE in terms of network architecture?

Answer: LTE uses a flat all-IP architecture; HSPA+ relies on the older 3G RNC/NodeB hierarchy

LTE introduced a flat, all-IP radio access network architecture (eNodeB without a separate RNC), simplifying the network and reducing latency compared to HSPA+.