Question 48 from UPSC CSE 2019 - Science & Technology

Question

With reference to communications technologies, what are the differences between LTE (Long-Term Evolution) and VoLTE (Voice over Long-Term Evolution)? 1. LTE is commonly marketed as 3G and VoLTE is commonly marketed as advanced 3G. 2. LTE is dataâonly technology and VoLTE is voiceâonly technology. Select the correct answer using the code given below.

A

1 only

B

2 only

C

Both 1 and 2

D

Neither 1 nor 2

IASCODEX · Accepted Answer

Correct Option: D. Neither 1 nor 2

Strategy: Spot the claims about LTE and VoLTE marketing and technology type. LTE is never marketed as 3G; it refers to 4G standards. VoLTE is not advertised as advanced 3G but as high-definition voice on 4G. The data‐only and voice‐only distinction is incorrect: LTE enables high-speed data (with older mobile voice falling back on 2G/3G), and VoLTE enables voice calls as data packets on LTE. Both statements are factually incorrect, so the answer is option D.

Key Info: LTE (Long-Term Evolution) is a standard for wireless broadband communications commonly known as 4G LTE, designed to provide high-speed mobile internet and greater network efficiency compared to 3G (UMTS/HSPA). LTE supports only packet-switched data; traditional circuit-switched voice calls usually fall back to older networks (2G/3G) unless VoLTE is implemented. VoLTE (Voice over Long-Term Evolution) is an enhancement that allows voice calls (which are typically circuit-switched) to be transmitted as data packets over the LTE (4G) network, enabling high-definition voice quality, simultaneous voice and data, faster call setup, and better spectral efficiency. Unlike the statements, LTE is not marketed as 3G but as 4G, and VoLTE is not marketed as advanced 3G—both relate to the 4G ecosystem. Neither technology is 'data-only' or 'voice-only'; LTE is data-only unless supplemented with a technology like VoLTE for voice. VoLTE enables both voice and data transmission concurrently on 4G networks. Major telecom operators worldwide use LTE and VoLTE for improved user experience, transitioning from legacy 2G/3G voice to all-IP voice networks.

IASCODEX · Answer

Option A: 1 only

IASCODEX · Answer

Option B: 2 only

IASCODEX · Answer

Option C: Both 1 and 2