| Concept | Description |
|---|---|
Definition | Network that uses radio waves, microwaves, or infrared signals to connect devices without physical cables. Enables mobility and flexibility. |
Characteristics | Shared medium, limited bandwidth, interference, mobility, security challenges |
Frequency Bands | ISM bands (2.4GHz, 5GHz), cellular bands (700MHz-3.5GHz), satellite bands |
| Wireless Technologies | Description |
|---|---|
WiFi (802.11) | Local wireless networking using various standards (a/b/g/n/ac/ax/ay) |
Cellular (1G-5G) | Mobile communication networks with increasing data rates and capabilities |
Bluetooth | Short-range wireless communication for device pairing |
Zigbee | Low-power, low-data-rate wireless networking for IoT devices |
| WiFi Standards | Description |
|---|---|
802.11a | 5GHz, up to 54 Mbps, OFDM modulation |
802.11b | 2.4GHz, up to 11 Mbps, DSSS modulation |
802.11g | 2.4GHz, up to 54 Mbps, OFDM modulation |
802.11n | 2.4GHz/5GHz, up to 600 Mbps, MIMO technology |
802.11ac | 5GHz, up to 6.9 Gbps, MU-MIMO |
802.11ax | WiFi 6, 2.4GHz/5GHz, up to 9.6 Gbps, OFDMA |
| Cellular Generations | Description |
|---|---|
1G | Analog voice communication (1980s) |
2G | Digital voice and SMS (GSM, CDMA) |
3G | Mobile internet, up to 2 Mbps |
4G/LTE | IP-based, up to 100 Mbps mobile, 1 Gbps stationary |
5G | Ultra-low latency, massive IoT, up to 20 Gbps |
| Network Topologies | Description |
|---|---|
Infrastructure | Devices connect through access points (APs) to wired network |
Ad-hoc | Peer-to-peer connections without central infrastructure |
Mesh | Devices relay data for other devices, self-healing network |
Cellular | Base stations cover geographic areas (cells) |
| Challenges | Description |
|---|---|
Interference | Signal degradation from other devices, physical obstacles |
Security | Vulnerabilities to eavesdropping, unauthorized access |
Mobility | Handoff between access points/base stations |
Power Management | Battery conservation in mobile devices |
| Protocols & Standards | Description |
|---|---|
MAC Protocols | CSMA/CA (WiFi), TDMA (cellular), frequency hopping |
Security | WEP, WPA, WPA2, WPA3 for WiFi; AKA for cellular |
Quality of Service | 802.11e for WiFi, QoS classes in cellular |
| Emerging Technologies | Description |
|---|---|
WiFi 6E/7 | 6GHz band, higher throughput, lower latency |
5G Advanced | Enhanced 5G with improved capabilities |
Li-Fi | Light-based wireless communication |
Satellite Internet | Low Earth Orbit (LEO) constellations (Starlink) |