Wireless Networking
Wireless Networking
Wireless Networking enables communication without physical cables, using radio waves.
Types
| Type | Description |
|---|---|
| WLAN | Wireless Local Area Network |
| WWAN | Wide Area (cellular) |
| WPAN | Personal area (Bluetooth) |
Basic Architecture
Device → Access Point → Internet
Advantages
- Mobility
- Easy installation
- Flexibility
Wireless LAN (WLAN) Overview
A local wireless network connecting devices within limited area.
Components
- Access Point (AP)
- Wireless devices
- Router
WLAN Diagram
Laptop → AP → Router → Internet
Phone → AP
MAC Issues in WLAN
Problems
| Issue | Description |
|---|---|
| Hidden Terminal | Two nodes can't see each other |
| Exposed Terminal | Unnecessary blocking |
| Collision | Data conflict |
| Power Saving | Battery management |
Hidden Terminal Problem
A → B ← C
(A and C cannot hear each other)
IEEE 802.11 (Wi-Fi Standard)
Standard for wireless LAN communication.
Key Features
- Uses CSMA/CA (collision avoidance)
- Supports multiple speeds
- Operates in 2.4 GHz / 5 GHz
Versions
| Version | Speed |
|---|---|
| 802.11a | 54 Mbps |
| 802.11b | 11 Mbps |
| 802.11g | 54 Mbps |
| 802.11n | 600 Mbps |
Working
Device → Check Channel → Send Data → ACK
Bluetooth
Short-range wireless technology for device-to-device communication.
Features
- Low power
- Range ~10 meters
- Used in headphones, IoT
Bluetooth Network (Piconet)
Master Device → Slave Devices
Wireless Multiple Access Protocol
Protocols allowing multiple users to share same medium.
Types
| Protocol | Description |
|---|---|
| FDMA | Frequency division |
| TDMA | Time division |
| CDMA | Code division |
Comparison
| Method | Advantage |
|---|---|
| FDMA | Simple |
| TDMA | Efficient |
| CDMA | High capacity |
TCP over Wireless
Problem
TCP assumes no losses, but wireless has frequent losses.
Issues
| Issue | Description |
|---|---|
| Packet Loss | Due to signal errors |
| Latency | High delay |
| Throughput | Reduced speed |
Solutions
- TCP Reno/New Reno
- Split TCP
- Error correction
Wireless Applications
Examples
| Application | Description |
|---|---|
| Mobile Banking | Financial services |
| GPS Navigation | Location tracking |
| IoT Devices | Smart homes |
| Video Streaming | YouTube, OTT |
Data Broadcasting
Sending data to multiple users simultaneously.
Types
| Type | Description |
|---|---|
| Push-based | Server sends data |
| Pull-based | Client requests |
Broadcasting
Server → Multiple Clients
Mobile IP
Allows mobile devices to maintain same IP while moving.
Components
| Component | Description |
|---|---|
| Home Agent | Permanent IP manager |
| Foreign Agent | Temporary network |
| Care-of Address | Temporary IP |
Mobile IP Working
Mobile → Foreign Network → Home Agent → Internet
WAP (Wireless Application Protocol
Protocol for accessing web services on mobile devices.
WAP Architecture
Architecture Diagram
Mobile → WAP Gateway → Web Server
Components
- Mobile Device
- WAP Gateway
- Web Server
WAP Protocol Stack
Stack Layers
| Layer | Function |
|---|---|
| WAE | Application environment |
| WSP | Session layer |
| WTP | Transaction |
| WDP | Data transport |
WAP Application Environment (WAE)
Environment for running mobile applications.
Features
- Supports WML (Wireless Markup Language)
- Lightweight apps
WAP Working
User Request → WAP Gateway → Convert → Server → Response
WAP Applications
Examples
- Mobile browsing
- Email access
- News services
Important Exam Questions
Short Questions
- Define IEEE 802.11
- What is Bluetooth?
- What is Mobile IP?
Long Question
- Explain WLAN architecture and MAC issues
- Describe WAP architecture and protocol stack
- Explain TCP issues over wireless networks
Case-Based Questions
- Solve hidden terminal problem
- Explain Mobile IP with diagram
- Compare FDMA, TDMA, CDMA
Final Summary
- Wireless Networking → communication without cables
- IEEE 802.11 → Wi-Fi standard
- Bluetooth → short-range communication
- Mobile IP → mobility support
- WAP → mobile web protocol
- MAC issues → hidden/exposed terminal
Tags:
Mobile Computing