---
title: "Short note: LTE"
subject: "Wireless Communication"
chapter: 8
key: "semester_7/wireless_communication:lte-short-note"
source: https://www.bctengineer.com/q/semester_7/wireless_communication/lte-short-note
site: BCT Engineering
---

# Short note: LTE

Wireless Communication · Chapter 8: Wireless Systems and Standards

- Asked in: 2072 Asoj, 3 marks
- Video: [3.1 - LTE 4G ARCHITECTURE BASICS - INTRODUCTION](https://www.youtube.com/watch?v=1j4UwsdD9Qs) — LTE
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/wireless_communication/lte-short-note
- Whole chapter: https://www.bctengineer.com/md/semester_7/wireless_communication/chapter-8

## Question

Write a short note on LTE.

## Short answer

LTE is the 4G 3GPP standard (Release 8), using OFDMA downlink, SC-FDMA uplink, MIMO, and flexible bandwidths up to 20 MHz. Peak rates reach 300 Mbps down, 75 Mbps up, with sub-10 ms radio latency, and a flat all-IP architecture with eNodeBs and the Evolved Packet Core.

## Answer

**LTE (Long Term Evolution)** is the 4G mobile broadband standard of **3GPP (Release 8 onward)**, designed for high data rates, low latency and an all-IP network.

- **Air interface**: **OFDMA** in the downlink and **SC-FDMA** in the uplink (lower peak-to-average power for mobile batteries); QPSK, 16-QAM, 64-QAM; **MIMO** (up to 4×4).
- **Bandwidth**: flexible 1.4, 3, 5, 10, 15, 20 MHz; FDD and TDD.
- **Peak rates**: about 300 Mbps down and 75 Mbps up (Rel-8); LTE-Advanced reaches 1 Gbps with carrier aggregation.
- **Latency**: under 10 ms on the radio side.
- **Architecture**: flat — UE, **eNodeB**, and the Evolved Packet Core (MME, S-GW, P-GW, HSS); voice carried as VoLTE.

```text
 [UE]~~[eNodeB]--[MME / S-GW]--[P-GW]--Internet
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Which multiple access schemes does LTE use?
   A. SC-FDMA downlink, OFDMA uplink
   B. CDMA both
   C. OFDMA downlink, SC-FDMA uplink
   D. TDMA both
   Answer: C. SC-FDMA has lower PAPR, saving mobile battery. (Key point: Multiple access)

2. What channel bandwidths does LTE support?
   A. Only 1.25 MHz
   B. 1.4, 3, 5, 10, 15, 20 MHz
   C. Only 200 kHz
   D. 5 and 10 kHz
   Answer: B. LTE is flexible in bandwidth, FDD and TDD. (Key point: Bandwidth)