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Science and Technology Class 01

Previous Class Topic

  • Copper wire and optical fiber

Concept of “Mobile” and the Origin of the Term “Cell Phone”

  • Mobile is rooted in the idea of movement, contrasting with landline technologies.
  • The term cell phone arises from the presence of cells, each cell being the coverage area under a particular tower’s range.
  • When a phone user moves from one tower’s area (cell) to another, handover occurs between cells.

Mobile Generations

Zero Generation (0G) or Radio Phone/Taxi Phone

  • Introduced in 1971 in Finland.
  • Functioned like radio taxis, relying on radio waves and installed directly in vehicles.
  • Did not require towers, so it was mobile but not a cell-based phone.
  • Comparable to a modern walkie-talkie system, allowing limited-range communication.

First Generation (1G) – FDMA (Frequency Division Multiple Access)

  • Introduced in 1979 in Japan.
  • Marked the start of the cell phone era through the use of towers.
  • Relied on analog signals.
  • Characterized by substantial limitations:
    • Poor voice quality.
    • Large handset sizes.
    • High battery consumption.
    • Limited security.
    • Slow internet speed (~2.4 kbps).

Second Generation (2G) – TDMA and CDMA

  • Appeared in 1991 in Finland.
  • Transitioned to digital signals, addressing 1G’s constraints.
  • Enhanced voice quality, reduced handset size, better battery efficiency, improved security.
  • Achieved ~64 kbps internet speed.
  • Introduced text SMS services.

2.5G (GPRS)

  • General Packet Radio Services offered internet access via mobile networks.
  • Required compatible phones supporting GPRS to enable basic web browsing and email.
  • Speeds of roughly 144 kbps eventually became achievable.

2.75G (EDGE)

  • Enhanced Data Rate for GSM Evolution improved upon 2.5G.
  • Offered speeds up to about 384 kbps or sometimes aggregated to 432 kbps.
  • Demanded specific handset support and primarily competed with CDMA.

Third Generation (3G)

  • Globally introduced around 2001.
  • Provided higher speeds (up to around 3.1 Mbps) than 2G.
  • Enabled video conferencing, mobile TV, and early GPS services on phones.
  • Security and international roaming were notably improved.

Fourth Generation (4G)

  • Emerged globally by 2009.
  • Reached speeds up to 1 Gbps under ideal conditions.
  • Enabled features like LTE, VoLTE, WiMAX, and HSPA+.
  • Facilitated widespread high-speed applications, 4K video streaming, wearable device connectivity, and the Internet of Things.
  • Global mobility became more effortless without requiring additional arrangements for roaming.

Fifth Generation (5G)

  • Implemented around 2018 in many regions.
  • Offers speeds up to 10 Gbps or higher.
  • Provides extremely low latency, enhancing real-time applications such as live streaming, virtual reality, and high-speed IoT.
  • Operates on millimeter-wave (30–300 GHz) frequencies, deemed safe with minimal body absorption.

LTE vs. VoLTE (Within 4G)

  • Long Term Evolution (LTE)
    • Requires applications (e.g., internet calling apps) for voice calls over data.
    • Download speed may slow if a voice call arrives while downloading data.
  • Voice over Long Term Evolution (VoLTE)
    • Allows direct voice calls over the data network without a separate app.
    • Calls and data usage occur simultaneously without speed reduction.
    • Improves call quality and overall efficiency.

Standalone 5G vs. Non-Standalone 5G

5G Type Infrastructure Latency Deployment Speed Investment Core Network
Standalone Independent 5G Ultra-low latency Slower Higher cost Dedicated 5G core, does not rely on 4G
Non-Standalone Built on 4G Low latency Faster Lower initial cost Uses 4G core for control and operations

Standalone entails building entirely new infrastructure, ensuring more robust performance but requiring significant investment. Non-standalone leverages existing 4G infrastructure, enabling quicker installation at lower cost but with slightly higher latency compared to standalone.

Internet Governance and Data-Related Discussions

Data Localization and Data Protection

  • Many popular platforms store user data on foreign servers, potentially risking privacy if data leaves national boundaries.
  • Governments encourage or mandate data localization, requiring companies to host servers and data domestically for security.
  • The Justice Srikrishna Committee proposed guidelines for India’s data protection framework, influencing legislation like the Data Protection Bills of 2018 and 2023.
  • Edge computing and the establishment of local data centers address security, latency, and sovereignty concerns by keeping data closer to users.

Net Neutrality

  • Net neutrality means treating all internet traffic equally, without preferential speed or blocking.
  • Violations can include throttling or blocking specific sites or services, harming smaller businesses or individual users.
  • Regulatory bodies, such as India’s TRAI and corresponding commissions worldwide, often impose rules to preserve neutrality, ensuring no unfair advantage is given to particular platforms.
  • Certain specialized services (e.g., autonomous vehicles, telemedicine) may justifiably receive priority to ensure public safety and welfare.

Networking

Definition and Types of Networks

Networking involves connecting and sharing data across distances via communication technologies. Categorized by coverage range and connectivity:

  • PAN (Personal Area Network)
    Very short-range, connecting devices close to an individual. Examples include Bluetooth, NFC, and Wi-Fi Direct used for local connections such as file transfer or connecting wearables.
  • LAN (Local Area Network)
    Covers a limited geographical area like an office, home, or campus. Allows devices (computers, CCTV cameras, printers) within one building or cluster to communicate. Wi-Fi hotspots and cordless phones are often part of LAN connectivity.
  • MAN (Metropolitan Area Network)
    Spans a city-wide region, often using technologies like certain radio networks or potential expansions of WiMAX. FM radio and city-level wireless distribution systems can be viewed as MAN variants.
  • WAN (Wide Area Network)
    Extends over large distances, often national-scale or multi-regional. All India Radio broadcasts can serve as an example, or cross-regional phone connectivity with country codes.
  • GAN (Global Area Network)
    Operates at the global scale, exemplified by WWW (.com) and large-scale satellite or undersea cable networks connecting entire continents.

Wi-Fi Direct and Bluetooth

  • Wi-Fi Direct
    • Enables device-to-device communication without a central router.
    • Offers faster speeds (up to ~250 Mbps) and longer range (~600 ft) compared to basic Bluetooth.
    • Applications include Airdrop on certain devices, enabling rapid content sharing.
  • Bluetooth
    • Commonly operates in the 2.4–2.485 GHz radio band.
    • Lower transfer speeds (e.g., ~25 Mbps in Bluetooth 4.2, ~50 Mbps in newer versions).
    • Usually used for short-range data exchange like pairing headphones, keyboards, and other peripherals.

Wi-Fi (Wireless Fidelity)

Basics

  • Invented under the IEEE 802.11 standard in 1997.
  • Operates around 2.45 GHz, 5 GHz, and now 6 GHz frequencies, depending on the generation.

Generations of Wi-Fi

  • Wi-Fi 4 (802.11n) – Launched 2007, moderate data rates.
  • Wi-Fi 5 (802.11ac) – Launched 2013, higher speeds and better coverage.
  • Wi-Fi 6 (802.11ax) – Launched 2019, improved efficiency, speeds, and capacity for multiple devices.
  • Wi-Fi 6E – Introduced additional 6 GHz band in 2021 for lesser congestion.
  • Wi-Fi 7 (802.11be) – Anticipated around 2024, promises speeds up to 46 Gbps with multi-link operations and reduced latency.

Applications

  • Household routers providing home internet access.
  • Public hotspots in cafes, offices, educational institutions.
  • Supports concurrent connections for various devices, from laptops to smart TVs.

WiMAX (Worldwide Interoperability for Microwave Access)

  • Designed to cover broader areas than standard Wi-Fi (up to ~50 km).
  • Uses microwave frequencies, offering potential speeds of ~1 Gbps.
  • Intended for city-wide coverage without requiring multiple routers.
  • Despite promising features, large-scale adoption struggled due to implementation complexities, line-of-sight constraints, and competition from emerging cellular data technologies.

NFC (Near Field Communication)

  • Operates at 13.56 MHz with a range under ~4 cm to initiate communication.
  • Uses RFID (Radio-Frequency Identification) principles, often functioning without its own power in passive tags.
  • Commonly used for contactless payments, transit cards, and some smartphone-based transactions.
  • Transfer speeds vary (106–424 kbps), suited to secure, low-power operations.

Li-Fi (Light Fidelity)

  • Utilizes visible light (wavelength ~380–760 nm) from LED bulbs fitted with microchips for data transmission.
  • Invented by Harald Haas in 2011, with potential speeds up to 224 Gbps in experimental conditions.
  • Immune to electromagnetic interference, making it suitable for environments like airplanes or hospitals.
  • Cannot penetrate solid objects, meaning signals do not pass through walls.
  • Higher initial deployment cost, requiring multiple Li-Fi-enabled bulbs for thorough coverage.

VPN (Virtual Private Network)

  • Creates a secure, encrypted tunnel over a public or shared network.
  • Accessible via unique credentials (e.g., user ID and password) to ensure privacy.
  • Commonly used for accessing institutional resources or corporate intranets securely from off-site.
  • Ensures data confidentiality and integrity when communicating over potentially insecure networks.

Topic to be Discussed in the Next Class

  • Firewalls and cybersecurity