unit 2 Hinglish

Unit 2: Wireless WANs & Ad Hoc Wireless Networks

Wireless WANs (Wide Area Networks) aur Ad Hoc Networks wireless communication ka ek broad area cover karte hain. Ye communication systems modern technology ke base hain, jo logon aur devices ko seamlessly connect karte hain.

1. The Cellular Concept

Cellular systems wireless communication ka backbone hain. Inka primary goal hai large geographic areas ko efficiently cover karna aur spectrum reuse karna.

Key Features of Cellular Concept:

  1. Division into Cells: Ek bade geographic area ko multiple small regions (cells) mein divide kiya jata hai. Har cell ka ek Base Station (BS) hota hai.

    • Cells hexagonal shape mein visualize kiye jate hain (theoretical design), taaki efficient coverage ho aur overlapping avoid ho.

  2. Frequency Reuse: Alag cells ke beech same frequency reuse kiya jata hai, lekin unka distance aisa hota hai ki interference na ho. Example: Ek city mein same frequency multiple areas mein use ho sakti hai.

  3. Handover Mechanism: Jab ek user ek cell se dusre cell mein move karta hai, to call drop na ho iske liye handover mechanism implement hota hai. Example: Jab aap moving vehicle mein call karte hain aur signal seamless rehta hai.

Real-Life Scenario:

Aap jab ek crowded area mein ho aur sabhi mobile users apne phones use kar rahe hain, tabhi cellular network efficient coverage provide karta hai without interference.

2. Cellular Architecture

Cellular architecture ka primary goal hai wireless communication ko manage karna aur high capacity provide karna. Is architecture ke andar kai layers aur components hote hain jo ek network ko efficient banate hain.

Components of Cellular Architecture:

  1. Mobile Station (MS): Ye wo device hai jo user ke paas hoti hai, jaise mobile phones aur tablets.

  2. Base Station (BS): Ye ek fixed wireless transceiver hai jo ek particular cell ke andar communication ko manage karta hai.

  3. Mobile Switching Center (MSC): Ye ek network controller hai jo call switching aur routing operations karta hai.

  4. Base Station Controller (BSC): Ye multiple Base Stations ko manage karta hai aur handovers ko control karta hai.

  5. Gateway MSC (GMSC): Ye external networks (jaise PSTN ya internet) se connection establish karta hai.

Architecture Highlights:

  • Efficient frequency utilization ke liye cells ka design.

  • Seamless mobility ke liye handover mechanisms.

  • Call routing aur data management ke liye MSC.

3. Generations of Cellular Systems

Cellular systems ko development ke basis par generations mein divide kiya gaya hai.

1G (First Generation):

  • Technology: Analog

  • Features: Sirf voice communication. Poor quality aur security.

  • Example Devices: Early mobile phones (like Motorola DynaTAC).

2G (Second Generation):

  • Technology: Digital

  • Features:

    • Better voice quality

    • SMS (Short Message Service) aur MMS (Multimedia Messaging Service)

    • Improved security

  • Example Technologies: GSM (Global System for Mobile), CDMA (Code Division Multiple Access)

3G (Third Generation):

  • Technology: Digital with high-speed data

  • Features:

    • Faster internet

    • Video calling

    • Multimedia streaming

  • Example Technologies: WCDMA (Wideband CDMA), HSPA (High-Speed Packet Access)

Comparison Table:

Generation
Key Feature
Speed
Example Services

1G

Analog Voice

Low

Basic Voice Calls

2G

Digital Voice, SMS

14.4 Kbps

SMS, MMS, Voice Calls

3G

High-Speed Data

2 Mbps

Video Calls, Streaming

4. Wireless in Local Loop (WLL)

Wireless in Local Loop (WLL) ek technology hai jo fixed telephone lines ki jagah wireless communication ka use karti hai.

Advantages of WLL:

  1. No Wires: Infrastructure cost kaafi kam hota hai.

  2. Fast Deployment: Rural aur remote areas mein quickly deploy kiya ja sakta hai.

  3. Mobility: Limited mobility bhi provide karta hai.

Real-Life Use Case:

  • Rural areas mein landline telephone aur internet provide karne ke liye WLL ka use hota hai.

5. IEEE 802.11 Standard (Wi-Fi)

IEEE 802.11 ek wireless networking standard hai jo LANs (Local Area Networks) ke liye use hota hai.

Key Standards:

Standard
Frequency Band
Max Speed
Range

802.11a

5 GHz

54 Mbps

35 meters

802.11b

2.4 GHz

11 Mbps

38 meters

802.11g

2.4 GHz

54 Mbps

38 meters

802.11n

2.4/5 GHz

600 Mbps

70 meters

802.11ac

5 GHz

1 Gbps

100 meters

6. IEEE 802.16 Standard (WiMAX)

WiMAX (Worldwide Interoperability for Microwave Access) ek broadband wireless standard hai jo MANs (Metropolitan Area Networks) mein use hota hai.

Key Features of WiMAX:

  1. High-speed internet (up to 30 Mbps).

  2. Large range (10-50 kilometers).

  3. Suitable for both fixed and mobile connections.

Real-Life Example:

  • Rural areas mein broadband internet provide karne ke liye WiMAX ka use hota hai.

7. Wireless Internet & Mobile IP

Wireless Internet:

Wireless networks ke through internet access ko refer karta hai.

Mobile IP:

Ek protocol jo users ko ek network se dusre mein move karte waqt bhi stable connection deta hai.

Example Use Case:

Aap jab apne smartphone pe internet use karte hain aur ek Wi-Fi network se dusre Wi-Fi ya cellular network pe switch karte hain, to Mobile IP stable connection maintain karta hai.

8. Ad Hoc Wireless Networks

Ad Hoc networks wo networks hain jo infrastructure-less hote hain, jisme devices apas mein directly communicate karte hain.

Features of Ad Hoc Networks:

  1. Dynamic Topology: Devices freely move kar sakte hain.

  2. Self-Configuring: Central control ka absence.

  3. Scalability: Devices add/remove karna easy hota hai.

Real-Life Example:

  • Bluetooth sharing between two phones.

Detailed Mind Map

Wireless WANs & Ad Hoc Networks
    ├── Cellular Concept
    │     ├── Division into Cells
    │     ├── Frequency Reuse
    │     └── Handover Mechanism
    ├── Cellular Architecture
    │     ├── MS, BS, MSC
    │     ├── BSC, GMSC
    │     └── Call Routing
    ├── Generations of Cellular Systems
    │     ├── 1G: Analog Voice
    │     ├── 2G: Digital Voice, SMS
    │     └── 3G: High-Speed Data
    ├── Wireless in Local Loop (WLL)
    │     └── Landline Replacement
    ├── IEEE 802.11 Standard (Wi-Fi)
    │     ├── a/b/g/n/ac
    │     └── Frequency Bands
    ├── IEEE 802.16 Standard (WiMAX)
    │     └── Broadband MANs
    ├── Wireless Internet & Mobile IP
    │     └── Seamless Mobility
    └── Ad Hoc Wireless Networks
          ├── Decentralized
          └── Dynamic Topology

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